27354 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 194

[FRL—6014–9]

RIN 2060–AG85

Criteria for the Certification and

Recertification of the Waste Isolation

Pilot Plant’s Compliance With the

Disposal Regulations: Certification

Decision

AGENCY: Environmental Protection

Agency.

ACTION: Final rule.

SUMMARY: The Environmental Protection

Agency (‘‘EPA’’) is certifying that the

Department of Energy’s (‘‘DOE’’) Waste

Isolation Pilot Plant (‘‘WIPP’’) will

comply with the radioactive waste

disposal regulations set forth at

Subparts B and C of 40 CFR Part 191

(Environmental Standards for the

Management and Disposal of Spent

Nuclear Fuel, High-Level and

Transuranic Radioactive Waste). The

EPA is required to evaluate whether the

WIPP will comply with EPA’s standards

for the disposal of radioactive waste by

the WIPP Land Withdrawal Act

(‘‘LWA’’) of 1992, as amended. EPA’s

certification of compliance allows the

emplacement of radioactive waste in the

WIPP to begin, provided that all other

applicable health and safety standards,

and other legal requirements, have been

met. The certification constitutes final

approval under the WIPP LWA for

shipment of transuranic waste from

specific waste streams from Los Alamos

National Laboratory for disposal at the

WIPP. However, the certification is

subject to four specific conditions, most

notably that EPA must approve sitespecific waste characterization measures

and quality assurance programs before

other waste generator sites may ship

waste for disposal at the WIPP. The

Agency is amending the WIPP

compliance criteria (40 CFR Part 194) by

adding Appendix A that describes

EPA’s certification, incorporating the

approval processes for waste generator

sites to ship waste for disposal at the

WIPP, and adding a definition for

‘‘Administrator’s authorized

representative.’’ Finally, EPA is

finalizing its decision, also pursuant to

the WIPP LWA, that DOE does not need

to acquire existing oil and gas leases

near the WIPP to comply with the

disposal regulations.

EFFECTIVE DATE: This decision is

effective June 17, 1998. A petition for

review of this final action must be filed

no later than July 17, 1998, pursuant to

section 18 of the WIPP Land

Withdrawal Act of 1992 (Pub. L. 102–

579), as amended by the WIPP LWA

Amendments (Pub. L. 104–201).

FOR FURTHER INFORMATION CONTACT:

Betsy Forinash, Scott Monroe, or Sharon

White; telephone number (202) 564–

9310; address: Radiation Protection

Division, Center for the Waste Isolation

Pilot Plant, Mail Code 6602–J, U.S.

Environmental Protection Agency, 401

M Street S.W., Washington, DC 20460.

For copies of the Compliance

Application Review Documents

supporting today’s action, contact Scott

Monroe. The Agency is also publishing

a document, accompanying today’s

action, which responds in detail to

significant public comments that were

received on the proposed certification

decision. This document, entitled

‘‘Response to Comments,’’ may be

obtained by contacting Sharon White at

the above phone number and address.

Copies of these documents are also

available for review in the Agency’s Air

Docket A–93–02.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. What is the WIPP?

II. What is the purpose of today’s action?

III. With which regulations must the WIPP

comply?

IV. What is the decision on whether the

WIPP complies with EPA’s regulations?

A. Certification Decision

B. Conditions

C. Land Withdrawal Act Section 4(b)(5)(B)

Leases

D. EPA’s Future Role at the WIPP

(recertification, enforcement of

conditions)

V. What information did EPA examine to

make its decision?

VI. In making its final decision, how did EPA

incorporate public comments on the

proposed rule?

A. Introduction and the Role of Comments

in the Rulemaking Process

B. Significant Changes Made to the Final

Rule in Response to Comments

VII. How did EPA respond to general

comments on its proposed certification

decision?

VIII. How did EPA respond to major

technical issues raised in comments?

A. Content of Compliance Certification

Application (§ 194.14)

1. Site Characterization and Disposal

System Design

(a) Shaft Seals

(b) Panel Closure System

2. Results of Assessments, Input

Parameters to Performance Assessments,

Assurance Requirements, and Waste

Acceptance Criteria

3. Background Radiation, Topographic

Maps, Past and Current Meteorological

Conditions

4. Other Information Needed for

Demonstration of Compliance

5. Conclusion

B. Performance Assessment: Modeling and

Containment Requirements (§§ 194.14,

194.23, 194.31 through 194.34)

1. Introduction

2. Human Intrusion Scenarios

(a) Introduction

(b) Spallings

(c) Air Drilling

(d) Fluid Injection

(e) Potash Mining

(f) Carbon Dioxide Injection

(g) Other Drilling Issues

3. Geological Scenarios and Disposal

System Characteristics

(a) Introduction

(b) WIPP Geology Overview

(c) Rustler Recharge

(d) Dissolution

(e) Presence of Brine in the Salado

(f) Gas Generation Model

(g) Two-Dimensional Modeling of Brine

and Gas Flow

(h) Earthquakes

(i) Conclusion

4. Parameter Values

(a) Introduction

(b) Distribution Coefficient (Kd)

(c) Actinide Solubility

(d) Brine Pockets

(e) Permeability of Borehole Plugs

5. Other Performance Assessment Issues

(a) Sensitivity Analysis

(b) Performance Assessment Verification

Test

6. Conclusions

C. General Requirements

1. Quality Assurance (§ 194.22)

2. Waste Characterization (§ 194.24)

3. Future State Assumptions (§ 194.25)

4. Expert Judgment (§ 194.26)

5. Peer Review (§ 194.27)

D. Assurance Requirements

1. Active Institutional Controls (§ 194.41)

2. Monitoring (§ 194.42)

3. Passive Institutional Controls (§ 194.43)

4. Engineered Barriers (§ 194.44)

5. Consideration of the Presence of

Resources (§ 194.45)

6. Removal of Waste (§ 194.46)

E. Individual and Ground-water Protection

Requirements (§§ 194.51–55)

IX. Does DOE need to buy existing oil and

gas leases near the WIPP?

X. Why and how does EPA regulate the

WIPP?

A. The WIPP Land Withdrawal Act

B. Limits of EPA’s Regulatory Authority at

the WIPP

C. Compliance with Other Environmental

Laws and Regulations

XI. How has the public been involved in

EPA’s WIPP activities?

A. Public Involvement Prior to Proposed

Rule

B. Proposed Certification Decision

C. Public Hearings on Proposed Rule

D. Additional Public Input on the Proposed

Rule

E. Final Certification Decision, Response to

Comments Document

F. Dockets

XII. How will the public be involved in

EPA’s future WIPP activities?

XIII. Where can I get more information about

EPA’s WIPP activities?

A. Technical Support Documents
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27355

1 Department of Energy National Security and

Military Applications of Nuclear Energy

Authorization Act of 1980, Pub. L. 96–164, section

213.

2WIPP Land Withdrawal Act, Pub. L. 102–579,

section 2(18), as amended by the 1996 WIPP LWA

Amendments, Pub. L. 104–201. 3WIPP LWA, section 8(d). 4WIPP LWA, § 7(b).

B. WIPP Information Line, Mailing List,

and Internet Homepage

XIV. Regulatory Analysis/Administrative

Requirements

A. Executive Order 12866

B. Regulatory Flexibility

C. Paperwork Reduction Act

D. Unfunded Mandates Reform Act

E. Executive Order 12898

F. Small Business Regulatory Enforcement

Fairness Act of 1996

G. National Technology Transfer &

Advancement Act of 1995

H. Executive Order 13045—Children’s

Health Protection

I. What is the WIPP?

The Waste Isolation Pilot Plant

(‘‘WIPP’’) is a potential disposal system

for radioactive waste. Developed by the

Department of Energy (‘‘DOE’’ or ‘‘the

Department’’), the WIPP is located near

Carlsbad in southeastern New Mexico.

The DOE intends to bury radioactive

waste 2150 feet underground in an

ancient layer of salt which will

eventually ‘‘creep’’ and encapsulate

waste containers. The WIPP has a total

capacity of 6.2 million cubic feet of

waste.

Congress authorized the development

and construction of the WIPP in 1980

‘‘for the express purpose of providing a

research and development facility to

demonstrate the safe disposal of

radioactive wastes resulting from the

defense activities and programs of the

United States.’’ 1 The waste which may

be emplaced in the WIPP is limited to

transuranic (‘‘TRU’’) radioactive waste

generated by defense activities

associated with nuclear weapons; no

high-level waste or spent nuclear fuel

from commercial power plants may be

disposed of at the WIPP. TRU waste is

defined as materials containing alphaemitting radio-isotopes, with half lives

greater than twenty years and atomic

numbers above 92, in concentrations

greater than 100 nano-curies per gram of

waste.2

Most TRU waste proposed for

disposal at the WIPP consists of items

that have become contaminated as a

result of activities associated with the

production of nuclear weapons (or with

the clean-up of weapons production

facilities), e.g., rags, equipment, tools,

protective gear, and organic or inorganic

sludges. Some TRU waste is mixed with

hazardous chemicals. Some of the waste

proposed for disposal at the WIPP is

currently stored at Federal facilities

across the United States, including

locations in Colorado, Idaho, New

Mexico, Nevada, Ohio, South Carolina,

Tennessee, and Washington. Much of

the waste proposed for disposal at the

WIPP will be generated in the future.

II. What Is the Purpose of Today’s

Action?

Before disposal of radioactive waste

can begin at the WIPP, the U.S.

Environmental Protection Agency

(‘‘EPA,’’ or ‘‘the Agency’’) must certify

that the WIPP facility will comply with

EPA’s radioactive waste disposal

regulations (Subparts B and C of 40 CFR

Part 191).3 The purpose of today’s action

is to issue EPA’s certification decision.

With today’s action, EPA will add to

the Code of Federal Regulations a new

Appendix A to 40 CFR Part 194

describing EPA’s certification decision

and the conditions that apply to the

certification. The Agency is adding a

new section, § 194.8, to the WIPP

compliance criteria (40 CFR Part 194)

that describes the processes EPA will

use to approve quality assurance and

waste characterization programs at

waste generator sites. The EPA is also

adding a definition of the term

‘‘Administrator’s authorized

representative’’ to the WIPP compliance

criteria. Except for these actions, the

certification decision does not otherwise

amend or affect EPA’s radioactive waste

disposal regulations or the WIPP

compliance criteria.

Today’s action also addresses the

provision of section 7(b)(2) of the WIPP

Land Withdrawal Act which prohibits

DOE from emplacing transuranic waste

underground for disposal at the WIPP

until, inter alia, it acquires specified oil

and gas leases, unless EPA determines

that such acquisition is not necessary.

III. With Which Regulations Must the

WIPP Comply?

The WIPP must comply with EPA’s

radioactive waste disposal regulations,

located at Subparts B and C of 40 CFR

Part 191. These regulations limit the

amount of radioactive material which

may escape from a disposal facility, and

protect individuals and ground water

resources from dangerous levels of

radioactive contamination. In addition,

the compliance certification application

(‘‘CCA’’) and other information

submitted by DOE must meet the

requirements of the WIPP compliance

criteria at 40 CFR Part 194. The

compliance criteria implement and

interpret the general disposal

regulations specifically for the WIPP,

and clarify the basis on which EPA’s

certification decision is made.

IV. What Is the Decision on Whether

the WIPP Complies With EPA’s

Regulations?

A. Certification Decision

The EPA finds that DOE has

demonstrated that the WIPP will

comply with EPA’s radioactive waste

disposal regulations at Subparts B and

C of 40 CFR Part 191. This decision

allows the WIPP to begin accepting

transuranic waste for disposal, provided

that other applicable environmental

regulations have been met and once a

30-day Congressionally-required waiting

period has elapsed.4 EPA’s decision is

based on a thorough review of

information submitted by DOE,

independent technical analyses, and

public comments. The EPA determined

that DOE met all of the applicable

requirements of the WIPP compliance

criteria at 40 CFR Part 194. However, as

discussed below, DOE must meet

certain conditions in order to maintain

a certification for the WIPP and before

shipping waste for disposal at the WIPP.

B. Conditions

As noted above, EPA determined that

DOE met all of the applicable

requirements of the WIPP compliance

criteria. In several instances, however,

EPA found that it is necessary for DOE

to take additional steps to ensure that

the measures actually implemented at

the WIPP (and thus the circumstances

expected to exist there) are consistent

with DOE’s compliance certification

application (‘‘CCA’’) and with the basis

for EPA’s compliance certification.

Regarding several requirements, DOE

demonstrated compliance with the

applicable compliance criteria for only

one category of waste at a single waste

generator site. To address these

situations, EPA is amending the WIPP

compliance criteria, 40 CFR Part 194,

and appending four explicit conditions

to its certification of compliance for the

WIPP.

Condition 1 of the certification relates

to the panel closure system, which is

intended over the long term to block

brine flow between waste panels in the

WIPP. In its CCA, DOE presented four

options for the design of the panel

closure system, but did not specify

which one would be constructed at the

WIPP. The EPA based its certification

decision on DOE’s use of the most

robust design (referred to in the CCA as

‘‘Option D’’). The Agency found the

Option D design to be adequate, but also
27356 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

determined that the use of a Salado

mass concrete—using brine rather than

fresh water—would produce concrete

seal permeabilities in the repository

more consistent with the values used in

DOE’s performance assessment.

Therefore, Condition 1 of EPA’s

certification requires DOE to implement

the Option D panel closure system at the

WIPP, with Salado mass concrete

replacing fresh water concrete. (For

more detail on the panel closure system,

refer to the preamble discussion of

§ 194.14.)

Conditions 2 and 3 of the final rule

relate to activities conducted at waste

generator sites that produce the

transuranic waste proposed for disposal

in the WIPP. The WIPP compliance

criteria (§§ 194.22 and 194.24) require

DOE to have in place a system of

controls to measure and track important

waste components, and to apply quality

assurance (‘‘QA’’) programs to waste

characterization activities. At the time

of EPA’s proposed certification

decision, the Los Alamos National

Laboratory (‘‘LANL’’) was the only site

to demonstrate the execution of the

required QA programs and the

implementation of the required system

of controls. Therefore, EPA’s

certification constitutes final approval

under the WIPP LWA for DOE to ship

waste for disposal at the WIPP only

from the LANL, and only for the

retrievably stored (legacy) debris at

LANL for which EPA has inspected and

approved the applicable system of

controls. Before DOE may ship any

mixed (hazardous and radioactive)

waste from the LANL—even if it is

encompassed by the waste streams

approved by EPA in this action—DOE

must obtain any other regulatory

approvals that may be needed,

including approval from the State of

New Mexico under the Resource

Conservation and Recovery Act to

dispose of such waste at the WIPP.

As described in the final WIPP

certification, before other waste may be

shipped for disposal at the WIPP, EPA

must separately approve the QA

programs for other generator sites

(Condition 2) and the waste

characterization system of controls for

other waste streams (Condition 3). The

approval process includes an

opportunity for public comment, and an

inspection (of a DOE audit) or audit of

the waste generator site by EPA. The

Agency’s approval of waste

characterization systems of controls and

QA programs will be conveyed in a

letter from EPA to DOE. In response to

public comments on these conditions,

EPA’s approval processes for waste

generator site programs have been

incorporated into the body of the WIPP

compliance criteria, in a new section at

§ 194.8. (For more information on this

change, see the preamble section

entitled, ‘‘Significant Changes to the

Final Rule Made in Response to Public

Comments.’’ For further discussion of

Conditions 2 and 3, refer to the

preamble discussions of § 194.22 and

§ 194.24, respectively.)

Condition 4 of the certification relates

to passive institutional controls

(‘‘PICs’’). The WIPP compliance criteria

require DOE to use both records and

physical markers to warn future

societies about the location and contents

of the disposal system, and thus to deter

inadvertent intrusion into the WIPP.

(§ 194.43) In its application, DOE

provided a design for a system of PICs,

but stated that many aspects of the

design would not be finalized for many

years (even up to 100) after closure. The

PICs actually constructed and placed in

the future must be consistent with the

basis for EPA’s certification decision.

Therefore, Condition 4 of the

certification requires DOE to submit a

revised schedule showing that markers

and other measures will be

implemented as soon as possible after

closure of the WIPP. The DOE also must

provide additional documentation

showing that it is feasible to construct

markers and place records in archives as

described in DOE’s certification

application. After closure of the WIPP,

DOE will not be precluded from

implementing additional PICs beyond

those described in the application. (See

the preamble discussion of § 194.43 for

more information on PICs.)

Although not specified in the

certification, it is a condition of any

certification that DOE must submit

periodic reports of any planned or

unplanned changes in activities

pertaining to the disposal system that

differ significantly from the most recent

compliance application. (§ 194.4(b)(3))

The DOE must also report any releases

of radioactive material from the disposal

system. (§ 194.4(b)(3)(iii), (v)) Finally,

EPA may request additional information

from DOE at any time. (§ 194.4(b)(2))

These reports and information will

allow EPA to monitor the performance

of the disposal system and evaluate

whether the certification must be

modified, suspended, or revoked for any

reason. (Modifications, suspensions,

recertification, and other activities are

also addressed in the preamble section

entitled, ‘‘EPA’s Future Role at the

WIPP.’’)

C. Land Withdrawal Act Section

4(b)(5)(B) Leases

The EPA finds that DOE does not

need to acquire existing oil and gas

leases (Numbers NMNM 02953 and

02953C) (referred to as the ‘‘section

4(b)(5)(B) leases’’) in the vicinity of the

WIPP in order to comply with EPA’s

final disposal regulations at 40 CFR Part

191, Subparts B and C. The EPA

concludes that potential activities at

these existing leases would have an

insignificant effect on releases of

radioactive material from the WIPP

disposal system and, thus, that they do

not cause the WIPP to violate the

disposal regulations.

D. EPA’s Future Role at the WIPP

(recertification, enforcement of

conditions)

The EPA will continue to have a role

at the WIPP after this certification

becomes effective. As discussed above,

DOE must submit periodic reports on

any activities or conditions at the WIPP

that differ significantly from the

information contained in the most

recent compliance application. The EPA

may also, at any time, request additional

information from DOE regarding the

WIPP. (§ 194.4) The Agency will review

such information as it is received to

determine whether the certification

must be modified, suspended, or

revoked. Such action might be

warranted if, for example, significant

information contained in the most

recent compliance application were no

longer to remain true. The certification

could be modified to alter the terms or

conditions of certification—for example,

to add a new condition, if necessary to

address new or changed activities at the

WIPP. (§ 194.2) The certification could

be revoked if it becomes evident in the

future that the WIPP cannot or will not

comply with the disposal regulations.

Either modification or revocation must

be conducted by rulemaking, in

accordance with the WIPP compliance

criteria. (§§ 194.65–66) Suspension may

be initiated at the Administrator’s

discretion, in order to promptly reverse

or mitigate a potential threat to public

health. For instance, a suspension

would take effect if, during

emplacement of waste, a release from

the WIPP occurred in excess of EPA’s

containment limits. (See § 194.4(b)(3).)

In addition to reviewing annual

reports from DOE regarding activities at

the WIPP, EPA periodically will

evaluate the WIPP’s continued

compliance with the WIPP compliance

criteria and disposal regulations. As

directed by Congress, this

‘‘recertification’’ will occur every five
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27357

5WIPP LWA, § 8(f). Congress also directed that

this periodic recertification ‘‘shall not be subject to

rulemaking or judicial review.’’

years.5 For recertification, DOE must

submit to EPA for review the

information described in the WIPP

compliance criteria (although, to the

extent that information submitted in

previous certification applications

remains valid, it can be summarized and

referenced rather than resubmitted).

(§ 194.14) In accordance with the WIPP

compliance criteria, documentation of

continued compliance will be made

available in EPA’s dockets, and the

public will be provided at least a 30-day

period in which to submit comments.

The EPA’s decision on recertification

will be announced in the Federal

Register. (§ 194.64)

In the immediate future, the Agency

expects to conduct numerous

inspections at waste generator sites in

order to implement Conditions 2 and 3

of the compliance certification. Notices

announcing EPA inspections or audits

to evaluate implementation of quality

assurance (‘‘QA’’) and waste

characterization requirements at

generator facilities will be published in

the Federal Register. The public will

have the opportunity to submit written

comments on the waste characterization

and QA program plans submitted by

DOE. As noted above, EPA’s decisions

on whether to approve waste generator

QA program plans and waste

characterization systems of controls—

and thus, to allow shipment of specific

waste streams for disposal at the

WIPP—will be conveyed by a letter from

EPA to DOE. A copy of the letter, as

well as any EPA inspection or audit

reports, will be placed in EPA’s docket.

(See the preamble sections entitled

‘‘Dockets’’ and ‘‘Where can I get more

information about EPA’s WIPP

activities?’’ for more information

regarding EPA’s rulemaking docket.)

The procedures for EPA’s approval have

been incorporated in the compliance

criteria at a new section, § 194.8.

As discussed previously, Condition 1

of the WIPP certification requires DOE

to implement the Option D panel

closure system at the WIPP, with Salado

mass concrete being used in place of

fresh water concrete. It will be possible

to evaluate the closure system only

when waste panels have been filled and

are being sealed. At that time, EPA

intends to confirm compliance with this

condition through inspections under its

authority at § 194.21 of the WIPP

compliance criteria.

Similarly, EPA will be able to

evaluate DOE’s compliance with

Condition 4 of the certification only

when DOE submits a revised schedule

and additional documentation regarding

the feasibility of implementing passive

institutional controls. This

documentation must be provided to

EPA no later than the final

recertification application. Once

received, the information will be placed

in EPA’s docket, and the Agency will

evaluate the adequacy of the

documentation. If necessary, EPA may

initiate a modification to the

certification to address DOE’s revised

schedule; any such modification would

be undertaken in accordance with the

public participation requirements

described in the WIPP compliance

criteria, §§ 194.65–66. During the

operational period when waste is being

emplaced in the WIPP (and before the

site has been sealed and

decommissioned), EPA will verify that

specific actions identified by DOE in the

CCA and supplementary information

(and in any additional documentation

submitted in accordance with Condition

4) are being taken to test and implement

passive institutional controls. For

example, DOE stated that it will submit

a plan for soliciting archives and record

centers to accept WIPP information in

the fifth recertification application. The

Agency can confirm implementation of

such measures by examining

documentation and by conducting

inspections under its authority at

§ 194.21.

Finally, the WIPP compliance criteria

provide EPA the authority to conduct

inspections of activities at the WIPP and

at all off-site facilities which provide

information included in certification

applications. (§ 194.21) The Agency

expects to conduct periodic inspections,

both announced and unannounced, to

verify the adequacy of information

relevant to certification applications.

The Agency may conduct its own

laboratory tests, in parallel with those

conducted by DOE. The Agency also

may inspect any relevant records kept

by DOE, including those records

required to be generated in accordance

with the compliance criteria. For

example, EPA intends to conduct

ongoing inspections or audits at the

WIPP and at waste generator sites to

ensure that approved quality assurance

programs are being adequately

maintained and documented. The EPA

plans to place inspection reports in its

docket for public examination.

V. What Information Did EPA Examine

to Make its Decision?

The EPA made its certification

decision by comparing relevant

information to the WIPP compliance

criteria (40 CFR Part 194) and ensuring

that DOE satisfied the specific

requirements of the criteria in

demonstrating compliance with the

disposal regulations. The primary

source of information examined by EPA

was a compliance certification

application (‘‘CCA’’) submitted by DOE

on October 29, 1996. (Copies of the CCA

were placed in EPA’s Air Docket A–93–

02, Category II–G.) The DOE submitted

additional information after that time.

On May 22, 1997, EPA announced that

DOE’s application was deemed to be

complete. (62 FR 27996–27998)

However, as contemplated by

Congress, EPA’s compliance

certification decision is based on more

than the complete application. The EPA

also relied on materials prepared by the

Agency or submitted by DOE in

response to EPA requests for specific

additional information necessary to

address technical sufficiency concerns.

The Agency also considered public

comments on the proposed rule which

supported or refuted technical

positions. Thus, EPA’s certification

decision is based on the entire record

available to the Agency, which is

contained in EPA’s Air Docket A–93–02.

The record consists of the complete

CCA, supplementary information

submitted by DOE in response to EPA

requests for additional information,

technical reports generated by EPA and

EPA contractors, EPA audit and

inspection reports, and public

comments submitted on EPA’s proposed

certification decision during the public

comment period.

In response to public comments

regarding the precise materials EPA

considered in reaching its certification

decision, the Compliance Application

Review Documents (‘‘CARDs’’)

supporting today’s decision reference

the relevant portion(s) of the October 29,

1996, CCA and any supplementary

information that the Agency relied on in

reaching a particular compliance

decision. (Docket A–93–02, Item V–B–2)

All materials which informed EPA’s

proposed and final decisions have been

placed in the WIPP dockets or are

otherwise publicly available. A full list

of the supporting documentation for

EPA’s certification decision and the

DOE compliance documentation

considered by the Agency is located at

Docket A–93–02, Item V–B–1. For

further information regarding the

availability of information EPA

examined, see the section entitled

‘‘Dockets’’ in this preamble.
27358 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

6WIPP LWA, § 8(d)(2).

7 5 U.S.C. 553

VI. In Making its Final Decision, how

did EPA Incorporate Public Comments

on the Proposed Rule?

A. Introduction and the Role of

Comments in the Rulemaking Process

Congress directed that EPA’s

certification decision for the WIPP be

conducted by informal (or ‘‘notice-andcomment’’) rulemaking pursuant to

Section 4 of the Administrative

Procedure Act (‘‘APA’’).6 Notice-andcomment rulemaking under the APA

requires that regulatory agencies

provide notice of a proposed

rulemaking, an opportunity for the

public to comment on the proposed

rule, and a general statement of the basis

and purpose of the final rule.7 The

notice of proposed rulemaking required

by the APA must ‘‘disclose in detail the

thinking that has animated the form of

the proposed rule and the data upon

which the rule is based.’’ (Portland

Cement Ass’n v. Ruckelshaus, 486 F.2d

375, 392–94 (D.C. Cir. 1973)) The public

is thus enabled to participate in the

process by making informed comments

on the Agency’s proposal. This provides

the Agency the benefit of ‘‘an exchange

of views, information, and criticism

between interested persons and the

agency.’’ (Id.)

For the WIPP certification decision,

there are two primary mechanisms by

which EPA explains the issues that were

raised in public comments and the

Agency’s reactions to them. First, broad

or major comments are discussed in the

succeeding sections of this preamble.

Second, EPA is publishing a document,

accompanying today’s action and

entitled ‘‘Response to Comments,’’

which contains the Agency’s response

to all significant comments received

during the comment period on the

proposed certification decision. (The

EPA also responded to comments

received on its advance notice of

proposed rulemaking (‘‘ANPR’’); for

further information on the ANPR, see

the preamble section ‘‘Public

Involvement Prior to the Proposed

Rule.’’) The Response to Comments

document provides more detailed

responses to issues which are addressed

in the preamble, and addresses all other

significant comments on the proposal.

All comments received by EPA, whether

written or oral, were given equal

consideration in developing the final

rule.

B. Significant Changes to the Final Rule

Made in Response to Public Comments

Today’s action finalizes EPA’s

proposed decision that the WIPP facility

will comply with the disposal

regulations and that DOE does not need

to acquire existing oil and gas leases in

the WIPP Land Withdrawal Area. (For

further information, refer to the

preamble section entitled, ‘‘What is the

decision on whether the WIPP complies

with EPA’s regulations?’’) Beyond these

broad determinations, EPA’s proposed

certification decision also included four

conditions related to the panel closure

system, quality assurance at waste

generator sites, waste characterization

measures at waste generator sites, and

passive institutional controls. The final

rule retains all of these conditions.

However, in response to comments

submitted on the proposal, the Agency

has made clarifying changes to Subpart

A of 40 CFR Part 194 to provide a

clearer explanation of the process for

determining compliance with the

conditions related to waste generator

sites.

Proposed Conditions 2 and 3 relate to

quality assurance (‘‘QA’’) programs and

waste characterization programs,

respectively, at waste generator sites

intending to ship waste for disposal at

the WIPP. Except for removal of the

procedural sections of the proposed

conditions from the appendix (as

proposed) to Subpart A of 40 CFR Part

194, to provide for a clearer enunciation

of the process for determining

compliance with the conditions, these

conditions are retained with minor

clarifications in the final rule. The

conditions restrict DOE from shipping

waste to the WIPP from any sites other

than the Los Alamos National

Laboratory until EPA separately

approves the QA and waste

characterization plans at other waste

generator sites. For both QA and waste

characterization programs, the proposed

approval process included: placement

in the docket of site-specific

documentation submitted by DOE,

publication of a Federal Register notice

by EPA announcing a scheduled

inspection or audit, a period of at least

30 days for the public to comment on

information placed in the docket, and

the Agency’s written decision regarding

the approval of these programs in the

form of a letter from EPA to DOE. The

EPA proposed to approve QA programs

on a site-wide basis. However, because

the features of waste streams can vary

widely and thus can require

significantly different characterization

techniques, EPA proposed to approve

waste characterization measures and

controls on the basis of waste streams

or, where multiple waste streams may

be characterized by the same waste

characterization processes and

techniques, groups of waste streams.

A number of commenters suggested

that in the waste generator site approval

process, EPA should delay the public

comment period until after completion

of an inspection or audit, and should

make the Agency’s approval decision

explicitly subject to judicial review.

Other comments questioned the

authority for, and the value of, a

separate site approval process by EPA.

The EPA finds that it is both

necessary and within the Agency’s

authority to evaluate and approve sitespecific QA and waste characterization

programs. The compliance criteria

expressly provide that any certification

of compliance ‘‘may include such

conditions as [EPA] finds necessary to

support such certification.’’ (§ 194.4(a))

Before waste is shipped for disposal at

the WIPP, EPA must be confident that

the waste will conform to the waste

limits and other waste-related

assumptions incorporated in DOE’s

performance assessment—that is, that

DOE adheres to the fundamental

information and assumptions on the

waste on which the certification of

compliance is based. Such confidence

can be assured only by confirmation

that the required QA and waste

characterization programs are in place

(i.e., established, implemented or

executed) at waste generator sites. The

EPA believes that an approval process

separate from DOE’s internal procedures

is beneficial because DOE’s process is

not geared solely to confirming that

programs adhere to EPA’s compliance

criteria, and because DOE’s process does

not provide for public participation.

Given the great public interest

regarding the WIPP, and waste

characterization in particular, EPA

believes it is important that the public

be informed of and have the opportunity

to be involved in the site approval

process. To that end, EPA’s approval

process includes docketing information

relevant to site-specific approvals, and

allowing the public to comment on such

information.

The EPA’s certification that the WIPP

will comply with the 40 CFR Part 191

radioactive waste disposal regulations is

based on the Agency’s determination

that the WIPP will comply with the

containment requirements and other

requirements of 40 CFR Parts 191 and

194 for the waste inventory described

for purposes of the performance

assessment. In the CCA, DOE purported

to demonstrate that the WIPP would

meet the 40 CFR Part 191 release limits
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27359

by modeling the WIPP’s behavior in its

performance assessment. The

performance assessment incorporated

certain upper and lower limiting values

of specified waste components, as

required by 40 CFR 194.24(c). The EPA

confirmed the results of the

performance assessment using the same

upper and lower limiting values in the

performance assessment verification test

(‘‘PAVT’’). Those upper and lower

limiting values apply to contacthandled, remote-handled, and to-begenerated waste from numerous

generator sites. Thus, in today’s action,

EPA certifies that the WIPP will comply

with the 40 CFR Part 191 containment

requirements to the extent that

emplaced waste falls within the waste

envelope limits that were shown by the

performance assessment, and confirmed

by the PAVT, to be compliant with the

40 CFR Part 191 standards. Proposed

Conditions 2 and 3 change neither the

performance assessment assumptions

nor the terms on which the WIPP is

authorized for disposal, but rather

ensure that the assumptions on which

the compliance certification is based are

adhered to in practice.

Based on public comments, EPA also

finds it necessary to clarify that the

compliance criteria at § 194.22 and

§ 194.24 were not intended to require

that DOE address their requirements—

including QA measures, and the use of

process knowledge—for all waste

streams in the certification application

for the initial certification. Clearly, it

would be impossible to do so for the tobe-generated waste. It is similarly

impossible for DOE to demonstrate

fully, in the initial certification

application, that the waste emplaced in

the disposal system actually conforms to

the waste envelope (i.e., upper and

lower waste limits) upon which the

certification is based, since waste

cannot be disposed of at the WIPP

before EPA grants an initial

certification. Confusion on these issues

arose because the compliance criteria at

40 CFR Part 194 apply to information in

compliance recertification applications

as well as the initial certification

application.

The fact that it was not EPA’s intent

to require DOE to have implemented QA

or measurement programs for all waste

at every site prior to initial certification

is supported by numerous statements

made by the Agency at the time the

compliance criteria were issued. The

EPA had great discretion in setting the

waste characterization requirements,

since they were part of the general

requirements of the WIPP compliance

criteria and not derived directly from

the disposal regulations. In the

Response to Comments for 40 CFR Part

194, EPA emphasized that compliance

with the requirements would be

confirmed through inspections or audits

and would not serve to re-open the

certification rulemaking. (Docket A–92–

56, Item V–C–1, pp. 6–5, 6–8, and 6–20)

The Agency stated that the certification

rulemaking would address DOE’s

analysis of waste characteristics and

components and documentation that a

system of controls had been established

at the WIPP to track the amount of

important waste components emplaced

in the disposal system. (Docket A–92–

56, Item V–C–1, p. 6–9) The certification

rulemaking has addressed these issues

and found DOE in compliance with the

requisite criteria. The EPA believes that

the comprehensive waste

characterization approach described by

DOE in the CCA—including the

approach to identification, limitation,

and confirmation of waste components

important to containment of waste in

the disposal system—is an appropriate

basis for granting an initial certification.

The EPA further believes that

confirmation of the QA and system of

controls at waste generator sites (i.e.,

measuring and tracking important waste

components) can be reasonably obtained

by a process of inspections and audits

in accordance with 40 CFR 194.21,

194.22(e), and 194.24(h).

The EPA declines to modify the

proposed approval process by delaying

the comment period until after the

issuance of EPA’s inspection or audit

report. The EPA does not believe it is

prudent to commit to a strict sequence

of events that will be adhered to for

every approval. In some cases, the

Agency may place records of a

completed inspection or audit in the

docket prior to or during the public

comment period. However, in other

cases, the Agency believes that the

public comment period may better serve

members of the public if it allows them

to provide comments on DOE’s

documentation prior to EPA’s

inspection or audit. In this way, public

comments could inform EPA’s

inspection criteria and process, or

provide information on which EPA may

take action to follow up in the

inspection or audit. Therefore, the

Agency does not believe that it is

prudent to specify when the comment

period may occur in relation to an

inspection or audit. Furthermore, EPA

declines to make any statement

regarding whether the approval

decisions are subject to judicial review.

Jurisdiction of U.S. Federal Courts is

governed by the enactments of the U.S.

Congress.

Nevertheless, in response to

comments requesting changes or

clarifications to EPA’s waste generator

site and waste stream approval

processes, EPA made certain changes to

the proposed conditions. In order to

clarify EPA’s original intent in the

compliance criteria regarding approval

of site-specific activities, EPA is

amending the compliance criteria at 40

CFR Part 194 to include the site-specific

approval process. (See 62 FR 58804,

58815) Thus, the procedures for

demonstrating compliance with the

proposed Conditions 2 and 3 are

incorporated in the final rule as a new

section at 40 CFR Part 194: § 194.8,

‘‘Approval Process for Waste Shipment

from Waste Generator Sites for Disposal

at the WIPP.’’ Also, in response to

comments advocating greater

transparency in the approval process,

EPA has clarified that scheduled

inspections or audits by EPA for the

purpose of approving quality assurance

programs at waste generator sites will be

announced by notice in the Federal

Register (§ 194.8(a)); this is consistent

with EPA’s commitment to do so for

inspections and audits of waste

characterization programs at generator

sites (§ 194.8(b)). Providing notice of

such inspections will alert the public to

upcoming EPA approval activities and

allow for more informed public

participation. While public notice will

be provided for the scheduled initial

phase of an inspection or audit, should

it prove necessary for EPA to conduct

follow-up activities or continuations of

inspections and audits, EPA reserves the

right to do so without providing

additional public notice. Such followup activities or continuations of audits

or inspections might be necessary to

obtain additional information or ensure

that corrective actions are being taken to

resolve initial findings. In no case will

EPA decide whether to approve sitespecific quality assurance or waste

characterization programs before

providing a minimum 30-day public

comment period on documentation of

the program plans, or before conducting

an inspection or audit at the relevant

site.

The Agency received some comments

related to Conditions 1 and 4 in the

proposed rule. EPA’s responses to these

comments are discussed in the preamble

sections related to § 194.14 and

§ 194.43, respectively. Conditions 1 and

4 were retained without change in the

final rule. The response to comments

document accompanying today’s action

provides more detailed responses

regarding the certification conditions

and all aspects of the final rule.
27360 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

8WIPP Land Withdrawal Act (‘‘WIPP LWA’’),

Pub. L. 102–579, as amended by the 1996 WIPP

LWA Amendments, Pub. L. 104–201, Section 8(d). 9 18 U.S.C. 1905

The EPA received no significant

comments on its proposed actions to

slightly modify the criteria by revising

the authority citation and adding a new

definition for Administrator’s

authorized representative. Therefore,

these actions take effect without change

from the proposed rule.

VII. How Did EPA Respond to General

Comments on Its Proposed Certification

Decision?

The EPA received many comments

which addressed broad issues related to

the proposed certification decision.

Many citizens simply expressed their

strong support for, or opposition to,

opening the WIPP. Some commenters

requested that EPA consider certain

factors in making its certification

decision. These factors include reviews

by organizations other than EPA, and

the political or economic motivations of

interested parties. The EPA’s

certification decision must be made by

comparing the scope and quality of

relevant information to the objective

criteria of 40 CFR Part 194. Where

relevant, the Agency has considered

public comments which support or

refute technical positions taken by DOE.

Emotional pleas and comments on the

motives of interested parties are factors

that are not relevant to a determination

of whether DOE has demonstrated

compliance with the disposal

regulations and the WIPP compliance

criteria, and are therefore outside the

scope of this rulemaking.

A number of commenters suggested

that EPA should explore alternative

methods of waste disposal, such as

neutralizing radioactive elements,

before proceeding with a certification

decision. Others stated that the WIPP

should be opened immediately because

underground burial of radioactive waste

is less hazardous than the current

strategy of above-ground storage. Such

considerations are all outside the scope

of this rulemaking. Congress did not

delegate to EPA the authority to

abandon or delay the WIPP in favor of

other disposal methods. Congress

mandated that EPA certify, pursuant to

Section 4 of the APA, whether the WIPP

will comply with the radioactive waste

disposal regulations.8 Thus, EPA is

obligated to determine whether the

WIPP complies with the disposal

regulations, regardless of the relative

risks of underground disposal compared

to above-ground storage.

Many members of the public

expressed a desire for EPA to oversee

other aspects of the WIPP’s operation. In

particular, the public was concerned

with the risks of transporting

radioactive materials from waste

generator sites to the WIPP. All

transportation requirements for the

WIPP are established and enforced by

regulators other than EPA. (For further

discussion on the source and limitations

of EPA’s authority to regulate the WIPP,

see preamble Section X, ‘‘Why and how

does EPA regulate the WIPP?’’) One

commenter stated that EPA should

survey electric and magnetic fields at

the WIPP. The EPA’s disposal

regulations apply only to ionizing

radiation. They do not apply to nonionizing radiations such as electric and

magnetic fields. These issues are beyond

the scope of EPA’s authority to regulate

waste disposal at the WIPP and are not

addressed in the certification

rulemaking.

The EPA received a number of

comments suggesting that the Agency

should have provided more or better

opportunities for public participation in

its decision making process. Comments

suggested, for example, that EPA should

have rescheduled public hearings,

responded more fully to comments

submitted prior to the proposed rule,

extended the public comment period,

and included the public in all meetings

between EPA and DOE. The EPA

provided numerous opportunities for

public participation in the WIPP

certification decision, including two

comment periods—one before and one

after the proposed decision—of at least

120 days (In fact, EPA accepted

comments on its advance notice of

proposed rulemaking announcing

receipt of DOE’s CCA for over 250

days.), two sets of public hearings in

New Mexico, Federal Register notices,

and a number of meetings with various

stakeholders. These measures exceed

the basic requirements for notice-andcomment rulemaking and are in full

compliance with the public

participation requirements of both the

WIPP compliance criteria and the

Administrative Procedure Act. Further

discussion on the measures taken by

EPA to involve the public can be found

in the preamble section entitled, ‘‘How

has the public been involved in EPA’s

WIPP activities?’’

Some members of the public

expressed doubt that EPA and its

contractors possessed the necessary

technical skills to evaluate DOE’s

application or were free from conflicts

of interest. Many comments requested

that EPA release the names and

qualifications of individual contractor

employees who provided technical

support for EPA’s certification

rulemaking. The EPA initially denied

this request because such information is

typically claimed as confidential

business information by federal

government contractors. (The Trade

Secrets Act prohibits EPA from

releasing confidential business

information, and imposes criminal

liability on federal employees for the

unauthorized disclosure of such

confidential information.9) However, in

response to the public interest regarding

this issue, EPA sought and obtained

from its contractors a limited waiver of

confidentiality to release the names and

qualifications of individual employees

who provided technical support related

to EPA’s certification decision. In

January 1998, EPA provided this

contractor information to several

stakeholders and also placed it in the

rulemaking docket. (Docket A–93–02,

Items IV–C–13 and IV–C–14) The

Agency also sent to stakeholders (and

docketed) a description of the measures

EPA has taken to ensure that contractors

do not have any conflict of interest in

providing technical support on the

certification rulemaking. While EPA

agreed to release the above information

to allay public concerns, such

information is not relevant to EPA’s

certification decision. Under notice-andcomment rulemaking, it is the substance

and basis for EPA’s decision that are at

issue.

Finally, several commenters stated

that EPA—by initially certifying the

WIPP to receive only certain waste from

the Los Alamos National Laboratory—is

granting a piecemeal certification, and

that such an action is illegal under

EPA’s regulatory authority. The EPA

disagrees with the assertion that its

actions constitute a phased certification.

The EPA’s certification is based on the

Agency’s determination that the WIPP

will comply with the disposal

regulations for the inventory described

in the performance assessment.

Conditions 2 and 3 of the certification

(related to waste generator sites) change

neither the performance assessment

assumptions nor the terms on which the

WIPP is authorized for disposal, but

ensure that DOE adheres to the

assumptions on which compliance is

based. The EPA believes this approach

is consistent with Congressional intent

(as reflected in the WIPP LWA) and

with the disposal regulations and

compliance criteria. For further

discussion of comments related to the

proposed conditions of certification,

refer to the preceding preamble section

entitled, ‘‘Significant Changes Made to
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27361

10Section 194.11 provides that EPA’s certification

evaluation would not begin until EPA notified DOE

of its receipt of a ‘‘complete’’ compliance

application. This ensures that the full one-year

period for EPA’s review, as provided by the WIPP

LWA, shall be devoted to substantive, meaningful

review of the application. (61 FR 5226)

the Final Rule in Response to

Comments.’’

VIII. How Did EPA Respond to Major

Technical Issues Raised in Comments?

A. Content of Compliance Certification

Applications (§ 194.14)

40 CFR Part 194 sets out those

elements which the Agency requires to

be in a complete compliance

application. In general, compliance

applications must include information

relevant to demonstrating compliance

with each of the individual sections of

40 CFR Part 194 to determine if the

WIPP will comply with the Agency’s

radioactive waste disposal regulations at

40 CFR Part 191, Subparts B and C. The

Agency published the ‘‘Compliance

Application Guidance for the Waste

Isolation Pilot Plant: A Companion

Guide to 40 CFR Part 194’’ (‘‘CAG’’)

which provided detailed guidance on

the submission of a complete

compliance application.10

Any compliance application must

include, at a minimum, basic

information about the WIPP site and

disposal system design, and must also

address all the provisions of the

compliance criteria; these requirements

are embodied in § 194.14. The

documentation required in the

compliance criteria is important to

enable a rigorous, thorough assessment

of whether the WIPP facility will

comply with the disposal regulations.

The EPA thoroughly reviewed DOE’s

compliance certification application

(‘‘CCA’’) and additional information

submitted by DOE, and proposed that

DOE complies with each of the

requirements of § 194.14, conditioned

upon DOE’s implementation of the most

robust panel closure system design

(designated as Option D) with slight

modification. The succeeding sections

address public comments related to

§ 194.14. (For more detailed

discussions, see Docket A–93–02, Item

V–B–2, CARD 14; and Item V–B–3.)

1. Site Characterization and Disposal

System Design

The EPA received numerous public

comments on issues related to the

requirements of §§ 194.14(a) and

194.14.(b), primarily related to the

geological features, disposal system

design and characteristics of the WIPP.

Since the geology and disposal system

characteristics are directly related to

performance assessment modeling and

the containment requirements of 40 CFR

Part 191, a discussion of EPA’s review

of the substantive comments (except for

those relating to shaft seals and panel

closures) can be found in the

Performance Assessment section of this

preamble. A discussion of the comments

on the engineered features related to

long term performance, specifically on

the shaft seal design and panel closure

system, are discussed below.

a. Shaft Seals. In the CCA, DOE

described the seals to be used in each

of the four shafts and included the

design plans and the material and

construction specifications for the seals.

(Docket A–93–02, Item II–G–1, CCA

Chapter 3.3.1, Chapter 8.1.1, and

Appendix SEAL) The purpose of the

shaft seal system is to limit fluid flow

within the shafts after the WIPP is

decommissioned and to ensure that the

shafts will not become pathways for

radionuclide release. The shaft seal

system has 13 elements that fill the shaft

with engineered materials possessing

high density and low permeability,

including concrete, asphalt, clay,

compacted salt, cementitious grout, and

earthen fill. The compacted salt column

component of the system within the

Salado is intended to serve as the

primary longterm barrier by limiting

fluid transport along the shaft during

the 10,000 year regulatory period. The

EPA proposed that DOE’s shaft seal

design is adequate because the system

can be built and is expected to function

as intended. (Docket A–93–02, Item V–

B–2, CARD 14, Section 14.E; and Item

V–B–3)

Commenters expressed concern that

dissolution of the salt column could

occur because the overlying Rustler

aquifer has karst features and cannot be

relied upon to retard the migration of

radionuclides. (For more information on

karst, refer to the preamble sections on

Performance Assessment, Geological

Scenarios.) Dissolution of salt (halite) in

the WIPP shafts would require a source

of water that is not saturated with salt,

and a sink, i.e., some location for the

water to flow to after it has dissolved

the salt in the shafts. Since all of the

ground water from the top of the Salado

downward is saturated with salt (i.e., it

is ‘‘brine’’), the unsaturated but highly

saline water would probably come

down the shaft from the Rustler

Formation. In order to reach the salt

component of the shaft seal, that water

would have to pass through or around

490 feet of concrete, asphalt, and

bentonite layers. Then, after flowing

through 550 feet of compacted salt

column, the saturated water would have

to flow through or around another

concreteasphalt water stop, another 100

feet of bentonite clay, and the shaft

station concrete plug. (Docket A–93–02,

Item V–B–2, CARD 14, Section 14.A)

Even if water were to pass through the

salt column, only a small fraction of the

salt column would be removed. Due to

the ongoing inward creep of the Salado

Formation, the salt column would still

be consolidated after such a dissolution

episode. Finally, DOE’s PA calculations

do not include ‘‘credit’’ for bentonite

swelling, capture of water by clay, or the

adsorption of water into dry halite’all

processes that would tend to reduce

water predicted to reach the salt

column’and the PA results are therefore

conservative. Therefore, EPA concludes

that dissolution of the salt column is not

a concern. (Docket A–93–02, Item V–B–

2, CARD 14, Section 14.E; Item V–B–3,

Section F.2)

Commenters questioned the ability of

the shaft seals to perform as expected

because the material and construction of

the seals have not been tested. However,

EPA found that DOE performed and

referenced numerous tests and

experiments to establish the material

characteristics of importance to

containment of waste at the WIPP. The

characteristic of primary importance is

the material’s permeability, the degree

to which fluids can travel through the

material. The permeability of concrete,

asphalt, and bentonite clay are well

documented, and DOE performed

numerous experiments to demonstrate

the applicability of these characteristics

to the WIPP’s site specific conditions

(e.g., high brine concentration). The

DOE documented many laboratory and

insitu tests of the permeability of

compacted crushed salt including a

largescale field test to demonstrate the

feasibility of implementing such a seal

measure. (Docket A–93–02, Item II–G–2,

Appendices SEAL, PCS, DEL, and

MASS)

The technology planned for

constructing the shaft seals has been

tested in the real world. The

construction equipment and procedures

necessary to emplace the seal materials

are in large part the same as those used

to excavate the WIPP, but used in

reverse. Except for salt, the shaft seal

component materials are commonly

used in construction. Salt has been

extensively tested to determine its

properties and behavior in the

conditions which will exist in the shafts

after the WIPP is closed. The EPA finds

that the shaft seal design has undergone

extensive technical review and testing

by DOE that shows it is feasible to

construct and is expected to perform as

intended. (Docket A–93–02, Item V–B–
27362 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

2, CARD 14, Section 14.E; Item V–B–3,

Section F.2)

As commenters pointed out, and EPA

agrees, many changes may occur in

knowledge of construction materials

and in construction methods and

equipment during the 35 years before

the WIPP is expected to be closed. The

DOE provided a final design for the

shaft seals which could be constructed.

However, EPA recognizes the fact that

technology may change and expects the

shaft seal plans to be periodically

reviewed and revised to take full

advantage of new knowledge or

construction equipment in the future.

Acknowledgment of this circumstance

does not mean that the existing plans

are inadequate, or that major changes in

the design are anticipated. Periodic

review of the WIPP authorization(s) to

operate is required by the various

statutes and regulations applicable to

the WIPP, including EPA’s review of

recertification applications every five

years, and the State of New Mexico’s

review of the hazardous waste permit at

least every ten years. Shaft seal design

changes may be proposed by DOE and

perhaps approved by EPA several times

before the end of the WIPP disposal

operations phase. Significant changes in

the designs will be required to go

through public noticeandcomment

procedures before approval by EPA.

(§ 194.65–66)

b. Panel Closure System. Panel

closures are needed primarily during

active disposal operations at the WIPP

and during preparations for final closure

of the entire facility. Relative to longterm performance, they can serve to

block the flow of brine between panels.

The DOE provided four options for a

panel closure system in the CCA, but

did not specify which panel closure

option would be used at WIPP. The EPA

reviewed the four panel closure system

options proposed by DOE and

considered that the intended purpose of

the panel closure system is to prevent

the existing disturbed rock zone

(‘‘DRZ’’) in the panel access drifts

(tunnels) from increasing in

permeability after panel closure (which

could allow greater brine flow). The

EPA considers the panel closure system

design identified as ‘‘Option D’’ to be

the most robust panel closure design.

(Docket A–93–02, Item II–G–1, CCA

Chapter 3 and Appendix PCS; Item V–

B–2, CARD 14, Section 14.E; Item V–B–

3, Section F.2) The EPA based its

evaluation of compliance for the

proposed rule on the Option D panel

seal design and proposed to establish a

certification condition requiring DOE to

implement the Option D design. The

EPA believes that the proposed design

on which compliance was based should

be actually implemented at the site. The

EPA also proposed to require DOE to

use Salado mass concrete (concrete

made with Salado salt) for construction

of the concrete barrier component of the

panel closure. This substitution

eliminates the potential for degradation

and decomposition of fresh water

concrete by infiltration of brine. The

EPA determined that implementation of

Option D is adequate to achieve the

long-term performance modeled in the

PA, since DOE shows that the use of a

concrete barrier component is capable of

providing resistance to inward

deformation of the surrounding salt and

prohibiting growth of the DRZ from its

initial state. (Docket A–93–02, Item V–

B–13)

Contrary to public comments, EPA

found that the panel closures can be

constructed using currently available

and widely used technology. Mixing

and transportation of concrete, using

special measures to prevent segregation

of fine and coarse particles (as required

in the Panel Closure System

construction specifications), and

placement in confined spaces by

pumping, is used routinely in bridge

and building foundations, dams, and in

water supply, subway and highway

tunnels. The steel forms in which the

concrete will be confined are somewhat

unusual in shape, but the methods of

construction are fairly simple and

standardized. The Salado mass concrete

mix is specially formulated for use in

the WIPP, but it has been extensively

tested to determine its properties (e.g.,

strength and resistance to chloride

degradation) as explained in

‘‘Variability in Properties of Salado

Mass Concrete.’’ (Docket A–93–02, Item

II–G–1, Ref. No. 662)

One commenter asked that EPA revise

its panel seal design condition so that

DOE may reassess the engineering of

panel closures when panels are to be

closed in the future. The EPA proposed

a certification condition (Condition 1)

requiring DOE to implement the panel

seal design that it designated as Option

D in the CCA. The Option D design shall

be implemented as described in the

CCA, except that DOE is required to use

Salado mass concrete rather than fresh

water concrete. Nothing in this

condition precludes DOE from

reassessing the engineering of the panel

seals at any time. Should DOE

determine at any time that

improvements in materials or

construction techniques warrant

changes to the panel seal design, DOE

must inform EPA. If EPA concurs, and

determines that such changes constitute

a significant departure from the design

on which certification is based, the

Agency is authorized under § 194.65 to

initiate a rulemaking to appropriately

modify the certification. The EPA has

retained the proposed Condition 1,

related to the panel closure system,

without change in the final rule. (See

also ‘‘Conditions’’ and ‘‘Significant

Changes to the Final Rule’’ sections of

this preamble.)

2. Results of Assessments, Input

Parameters to Performance Assessments,

Assurance Requirements, and Waste

Acceptance Criteria

Sections 194.14(c) through (f) require

DOE to submit the results of

assessments conducted in accordance

with 40 CFR Part 194; a description of

the input parameters associated with

such assessments and the basis for

selecting such parameters;

documentation of measures taken to

meet the assurance requirements of 40

CFR Part 194; and a description of the

waste acceptance criteria and actions

taken to assure adherence to such

criteria. The EPA proposed that DOE

complied with §§ 194.14(c) through (f)

based on EPA’s finding that DOE

submitted the information required. The

EPA received numerous public

comments on the results of assessments,

input parameters to the PA, assurance

requirements, and the waste acceptance

criteria. A discussion of EPA’s

responses to substantive comments can

be found in the corresponding sections

of the preamble. Based on these

responses, EPA finds that DOE complies

with §§ 194.14(c) through (f). For further

discussion, refer to CARD 14, Sections

14.C, 14.D, 14.E, 14.F (Docket A–93–02,

Item V–B–2) and Sections H.2, I.2, J.2,

and K.2 of the technical support

document for § 194.14 (Docket A–93–02,

Item V–B–3).

3. Background Radiation, Topographic

Maps, Past and Current Meteorological

Conditions

For the CCA, DOE was required to

describe the background radiation in air,

soil and water in the vicinity of the

disposal system and the procedures

employed to determine such radiation

(§ 194.14(g)), provide topographic maps

of the vicinity of the disposal system

(§ 194.14(h)), and describe past and

current climatic and meteorological

conditions in the vicinity of the disposal

system and how these conditions are

expected to change over the regulatory

time frame (§ 194.14(i)). The EPA

proposed that DOE complied with the

requirements of §§ 194.14 (g), (h), and

(i). The EPA did not receive substantive

comments on these issues, except for

dissolution related to climate change. A
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27363

discussion of EPA’s response to the

substantive comments on dissolution

can be found in the Performance

Assessment, Geological Scenarios and

Disposal System Characteristics section

of this preamble. The EPA finds that

DOE complies with §§ 194.14 (g)

through (i). For further discussion, refer

to Sections 14.K, 14.L, and 14.M of

CARD 14 (Docket A–93–02, Item V–B–

2) and Sections H.2, L.2, N.2 and N.4 of

the technical support document for

§ 194.14 (Docket A–93–02, Item V–B–3).

4. Other Information Needed for

Demonstration of Compliance

The DOE was also required, under

§ 194.14(j), to provide additional

information, analyses, tests, or records

determined by the Administrator or the

Administrator’s authorized

representative to be necessary for

determining compliance with 40 CFR

Part 194. After receipt of the CCA dated

October 29, 1996, EPA formally

requested additional information from

DOE in seven letters dated December 19,

1996, and February 18, March 19, April

17, April 25, June 6, and July 2, 1997.

(Docket A–93–02, Items II–I–1, II–I–9,

II–I–17, II–I–25, II–I–27, II–I–33, and II–

I–37, respectively) The information

requested in these letters was necessary

for EPA’s completeness determination

and technical review. EPA staff and

contractors also reviewed records

maintained by DOE or DOE’s

contractors (e.g., records kept at the

Sandia National Laboratories Records

Center in Albuquerque, New Mexico).

No additional laboratory or field tests

were conducted by DOE at EPA’s

specific direction; however, DOE did

conduct and document laboratory tests

after October 29, 1996, in order to

present additional data to the

Conceptual Model Peer Review Panel.

(Docket A–93–02, Item II–A–39)

The EPA proposed that DOE complied

with § 194.14(j) because it responded

adequately to EPA’s formal requests for

additional information, analyses, and

records. The EPA did not formally

request additional information from

DOE after publication of the proposed

rule. However, in response to

comments, EPA did verbally ask DOE

and Sandia National Laboratory for

information and other assistance in

calculations related to the Hartman

scenario, drilling into fractured

anhydrite, and the CCDFGF code and

quasi-static spreadsheet with regard to

air drilling. (Docket A–93–02, Items IV–

E–24, IV–E–25, IV–E–26, and IV–E–27)

In addition, DOE voluntarily submitted

information on the proposed rule that

was considered as comments.

All documents sent to EPA regarding

certification of the WIPP are available in

EPA Air Docket A–93–02. Additional

information relevant to EPA’s

certification evaluation that was

reviewed by the Agency (e.g., DOE data

records packages, quality assurance

records, and calculations of actinide

solubility for americium, plutonium,

thorium and uranium) is also publicly

available. Documentation of peer review

panel meetings conducted after receipt

of the CCA has been placed in the EPA

docket. See Docket A–93–02, Item V–B–

1 for further information on the location

of all documentation reviewed by EPA.

5. Conclusion

The EPA received numerous public

comments on the proposed rule

regarding § 194.14. EPA has thoroughly

reviewed the public comments and

addressed all issues raised therein. On

the basis of its evaluation of the CCA

and supplementary information, and the

issues raised in public comments, EPA

finds that DOE complies with all

subsections of 40 CFR 194.14, with the

condition that DOE must fulfill the

requirements set forth in Condition 1 of

the final rule. For additional

information on EPA’s evaluation of

compliance for § 194.14, see CARD 14.

(Docket A–93–02, Item V–B–2)

B. Performance Assessment: Modeling

and Containment Requirements

(§§ 194.14, 194.23, 194.31 through

194.34)

1. Introduction

The disposal regulations at 40 CFR

Part 191 include requirements for

containment of radionuclides. The

containment requirements at 40 CFR

191.13 specify that releases of

radionuclides to the accessible

environment must be unlikely to exceed

specific limits for 10,000 years after

disposal. At the WIPP, the specific

release limits are based on the amount

of waste in the repository at the time of

disposal. (§ 194.31) Assessment of the

likelihood that the WIPP will meet these

release limits is conducted through the

use of a process known as performance

assessment (‘‘PA’’).

The WIPP PA process culminates in a

series of computer simulations that

attempts to describe the physical

attributes of the disposal system (site

characteristics, waste forms and

quantities, engineered features) in a

manner that captures the behaviors and

interactions among its various

components. The computer simulations

require the use of conceptual models

that represent physical attributes of the

repository. The conceptual models are

then expressed as mathematical

relationships, which are solved with

iterative numerical models, which are

then translated into computer code.

(§ 194.23) The results of the simulations

are intended to show the potential

releases of radioactive materials from

the disposal system to the accessible

environment over the 10,000-year

regulatory time frame.

The PA process must consider both

natural and man-made processes and

events which have an effect on the

disposal system. (§§ 194.32 and 194.33)

It must consider all reasonably probable

release mechanisms from the disposal

system and must be structured and

conducted in a way that demonstrates

an adequate understanding of the

physical conditions in the disposal

system. The PA must evaluate potential

releases from both human-initiated

activities (e.g., via drilling intrusions)

and natural processes (e.g., dissolution)

that would occur independently of

human activities. The DOE must justify

the omissions of events and processes

that could occur but are not included in

the final PA calculations.

The results of the PA are used to

demonstrate compliance with the

containment requirements in 40 CFR

191.13. The containment requirements

are expressed in terms of ‘‘normalized

releases.’’ The results of the PA are

assembled into complementary

cumulative distribution functions

(‘‘CCDFs’’) which indicate the

probability of exceeding various levels

of normalized releases. (§ 194.34)

As described above, 40 CFR Part 194

contains several specific requirements

for the performance assessment of

WIPP. It is often difficult to discuss one

of the requirements in isolation from the

others. For example, several public

comments raised concern about the

CCA’s screening of the fluid injection

scenario from the PA and EPA’s

subsequent analysis. In order for EPA to

adequately address the fluid injection

issue, the Agency must discuss multiple

requirements related to geology and

other characteristics specific to the

WIPP site (§ 194.14), models and

computer codes (§ 194.23), and the

screening process for both humaninitiated releases and releases by natural

processes (§§ 194.32 and 194.33).

Because so many of the PA issues have

similarly overlapping requirements and

are often complex, EPA has chosen to

combine the discussions. Therefore, the

following discussions are framed in

terms of the PA issues raised in

comments, rather than according to

specific PA requirements of the

compliance criteria. The following

sections discuss the major PA issues
27364 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

11 ‘‘Cuttings’’ refers to material, including waste,

that is cut by a drill bit during drilling and is

carried to the surface by the drilling fluid as it is

pumped out of the borehole.

12 ‘‘Cavings’’ refers to material that falls from the

walls of a borehole as a drill bit drills through.

Cavings are carried to the surface by the drilling

fluid as it is pumped out of the borehole.

13 ‘‘Spallings’’ refers to releases of solids pushed

up and out by gas pressure in the repository during

a drilling event.

that were raised during public hearings

and the public comment period. For

more information on performance

assessment and related issues, refer to

CARDs 14, 23, 32, and 33. (Docket A–

93–02, Item V–B–2)

2. Human Intrusion Scenarios

a. Introduction. Section 194.32

requires DOE to consider, in the PA,

both natural and man-made processes

and events which can have an effect on

the disposal system. Of all the features,

events, and processes (‘‘FEPs’’) that are

considered for the PA calculations, the

human-intrusion scenarios related to

drilling have been shown to have the

most significant impact on the disposal

system and its ability to contain waste.

(§ 194.33)

In preparing the CCA, DOE initially

identified 1,200 potential FEPs, both

natural and human-initiated, for the

WIPP PA. These FEPs were reduced in

number in the final PA calculations.

The DOE may eliminate FEPs from

consideration in the PA for three

reasons:

• Regulatory—FEPs can be omitted

based on regulatory requirements. For

example, drilling activities that occur

outside the Delaware Basin do not have

to be considered in the PA, according to

§§ 194.33(b)(3)(i) and 194.33(b)(4)(i).

• Probability—FEPs can be omitted

because of the low probability that the

FEP will occur. For example, DOE

determined that the probability of a

meteorite landing in the vicinity of the

WIPP is so low that it does not need to

be considered in the PA. (§ 194.32(d))

• Consequences—FEPS can be

omitted because the consequences

resulting from the FEP, even if it does

occur, are so small. For example, there

would be no consequences on the

repository or the containment of waste

if an archeological excavation took place

on the surface in the vicinity of the

WIPP. (§ 194.32(a))

The following sections discuss the

major public comments on human

intrusion scenarios. Generally, public

comments related to whether or not the

scenario was appropriately screened by

DOE and to EPA’s subsequent

evaluation of this screening. Some

comments addressed whether DOE’s

modeling of events was appropriate.

The human intrusion scenarios

discussed below are: spallings releases,

air drilling, fluid injection, potash

mining, and carbon dioxide injection.

For more information on human

intrusion scenarios, refer to CARDs 32

and 33. (Docket A–93–02, Item V–B–2)

b. Spallings. The DOE’s models for

the PA included five ways in which

radioactive waste could leave the

repository and escape to the accessible

environment: cuttings,11 cavings,12

spallings,13 direct brine release, and

transport of dissolved radionuclides

through the anhydrite interbeds (i.e.,

layers of rock immediately above the

repository). The first four of these

potential release pathways involve

direct releases of radiation to the earth’s

surface in cases where people drill a

borehole while searching for resources.

The DOE’s model for computing

releases of radiation due to spallings

was of particular concern to the

Conceptual Models Peer Review Panel

which reviewed each of the conceptual

models developed for the purposes of

the PA. (See Docket A–93–02, Item V–

B–2, CARD 23, Section 7.) The peer

review panel found the spallings

conceptual model inadequate because it

did not fully model all potential

mechanisms that may cause pressuredriven solid releases to the accessible

environment. (Docket A–93–02, Item II–

G–12, p. 74) The DOE presented

additional experimental evidence and

the results of other modeling to the peer

review panel and requested that it

consider whether the spallings volumes

predicted by the original inadequate

spallings model were reasonable for use

in the PA. (Docket A–93–02, Items II–G–

22 and II–G–23) After considering this

additional information, the peer review

panel concluded that the spallings

values in the CCA are reasonable for use

in the PA. The panel concluded that,

while the spallings model does not

accurately represent the future state of

the repository, its inaccuracies are

conservative and, in fact, may

overestimate the actual waste volumes

that would be expected to be released by

a spallings event. (Docket A–93–02,

Item II–G–22, Section 4, p. 18)

The spallings conceptual model

relates to the following requirements of

§ 194.23: documentation of conceptual

models used in the PA (§ 194.23(a)(1));

consideration and documentation of

alternative conceptual models

(§ 194.23(a)(2)); and reasonable

representation of future states of the

repository in conceptual models

(§ 194.23(a)(3)(i)). The EPA proposed

that DOE met the requirements of

§ 194.24(a)(1) and (a)(2), and, for all

conceptual models except the spallings

conceptual model, § 194.24(a)(3)(i). The

EPA did not propose, however, to

determine that the spallings model

incorporated in the CCA PA ‘‘reasonably

represents possible future states of the

repository,’’ as stated in § 194.24(a)(3)(i).

The EPA proposed to accept the

spallings model for the purposes of

demonstrating compliance with

§ 194.23(a)(3)(i) on the basis that it has

been determined to produce

conservative overestimates of potential

spallings releases. (62 FR 58807) The

Agency now concludes that DOE has

met the requirements of § 194.23 in its

final rule. (See Docket A–93–02, Item

V–B–2, CARD 23, Section 7.4.)

The public commented on four

aspects of DOE’s spallings modeling and

EPA’s evaluation of that modeling:

adequacy of DOE’s spallings modeling,

purpose and approach of EPA’s

spallings modeling, use of DOE’s

GASOUT code for modeling spallings,

and the need to include additional

spallings mechanisms.

Some commenters expressed concern

that DOE’s conceptual model for

spallings used in the PA did not

adequately represent spallings releases,

as stated initially by the Conceptual

Model Peer Review Panel. However,

others indicated that DOE had worked

on the spallings model extensively since

the peer review panel’s review, and that

the spallings model demonstrated that

the volume of releases due to spalling

would be small.

The EPA agrees that the spallings

conceptual model was inadequate to

represent possible future states of the

repository. In response to the

Conceptual Models Peer Review Panel,

DOE did substantial additional work,

developed a separate mechanisticallybased model and provided supporting

experimental data. The peer review

panel concluded that the spallings

model used in the CCA PA calculated

release volumes that were reasonable

and probably conservative. (Docket A–

93–02, Item II–G–22) On the basis of

this additional work, EPA concludes

that the spallings release volumes

calculated by the CCA spallings model

are acceptable. Based upon this work,

the Agency also agrees with those

commenters who stated that spallings

would result in only a small volume of

waste being released to the accessible

environment through spallings.

Commenters asked for clarification of

EPA’s purpose in producing its

spallings evaluation reports for the

proposed rule. (Docket A–93–02, Items

III–B–10 and III–B–11) They also

questioned EPA’s technical approach in

these reports, particularly the

discretization (time and space intervals).
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27365

14Tensile strength is resistance to being pulled

apart.

15 ‘‘Stuck pipe’’ means a situation where high gas

pressures in the repository would break off

radioactive waste and press it against a drill string

hard enough to stop or greatly reduce drilling. In

order to continue drilling, a drill operator would

raise and lower the drill string and, in the process,

could transport waste to the surface.

16 ‘‘Gas erosion’’ means a situation where

radioactive waste breaks off slowly due to high gas

pressures in the repository, enters drilling mud

surrounding the drill, and is transported to the

earth’s surface in the mud.

17 ‘‘Waste permeability’’ is the degree to which

fluid can move through the waste.

18 ‘‘Porosity’’ is the fraction of space present that

is open and can store gases or liquids, as opposed

to space filled by solid matter.

Discretization is important because if

intervals are too large, modeling may

not calculate or may incorrectly

calculate some important events, and if

intervals are too small, modeling will be

time-consuming and inefficient.

The EPA prepared its Spallings

Evaluation and Supplemental Spallings

Evaluation for the proposed rule in

order to model simplistically the

transport of spallings releases up a

borehole during blowout. The spallings

model used in the CCA PA did not

examine transport; rather, DOE’s

spallings model took the approach that

all waste broken loose and able to move

would actually reach the earth’s surface.

The Agency used an independent model

to investigate if DOE’s spallings

conceptual model would give

conservative estimates of spallings

releases. The EPA believed this would

determine if the calculated spallings

releases were potentially acceptable for

use in PA, despite the flaws in DOE’s

model. The EPA undertook these

studies early in its own review, and in

the Conceptual Models Peer Review

Panel’s review of the spallings

conceptual model, when both the Panel

and the Agency were concerned about

the results of the model.

After EPA completed its own

modeling, DOE performed additional

studies using an alternative,

mechanistic conceptual model for

spallings. (Hansen et al., Spallings

Release Position Paper, Docket A–93–

02, Item II–G–23) DOE’s additional

studies showed that its original

spallings conceptual model always

predicted a greater volume of releases

than the mechanistic spallings

conceptual model that used a more

realistic approach to calculate spallings

releases. As a result, both the

Conceptual Models Peer Review Panel

and EPA concluded that released

volumes estimated using the original

CCA spallings conceptual model were

reasonable and conservative. The EPA

found DOE’s analysis in the Spallings

Release Position Paper to be more

conclusive than the Agency’s studies in

its Spallings Evaluation and

Supplemental Spallings Evaluation.

DOE’s analysis was an improvement

over EPA’s analysis because it was more

thorough, it used much finer

discretization (smaller time and space

intervals) which allowed more specific

predictions, and it predicted both

volumes and activity of spallings

releases. As described in the proposed

rule, EPA examined the Spallings

Release Position Paper and concluded

that the spallings release volumes

calculated by the spallings model used

in the PA are conservative and,

therefore, acceptable to demonstrate

compliance with the waste containment

requirements of 40 CFR 191.13. (62 FR

58807) This conclusion is based not on

the EPA’s spallings reports prepared for

the proposed rule, which have been

questioned by commenters, but on the

additional spallings analysis performed

by DOE, presented to the Conceptual

Models Peer Review Panel, and found

by EPA to demonstrate that the spallings

release volumes used in the CCA PA are

conservative. (Docket A–93–02, Item III–

B–2; Item V–B–2, CARD 23; and Item V–

C–1)

Some commenters expressed concern

about the stability of Sandia National

Laboratory’s GASOUT computer code

that calculates spallings releases. One

individual had used this code to

calculate spallings releases due to air

drilling, but other commenters stated

that it was not appropriate to apply the

GASOUT code to the air drilling

scenario. (Air drilling refers to the

practice of using air or other substances

lighter than mud as a drilling fluid.)

The EPA agrees that the GASOUT

code may not be stable under some

conditions. GASOUT was designed to

model blowout of waste during the first

few seconds after borehole penetration,

where the driller uses mud in the

borehole to reduce friction during

drilling. The GASOUT code was only

intended to be used under specific

conditions of waste tensile strength 14

and permeability. (Docket A–93–02,

Item II–E–9) Within its range of

applicability, GASOUT produces results

that are consistent with results obtained

by other modeling approaches, such as

the quasi-static model and the coupled

numerical model. (Docket A–93–02,

Item II–G–23) However, if GASOUT is

not used as designed, it may well be

unstable or may calculate invalid

results. In particular, EPA agrees with

those commenters stating that it is

inappropriate to use GASOUT to

analyze the releases of spallings due to

air drilling. The programmer of the

GASOUT code himself has said that this

code was not designed to model drilling

using compressible fluids such as air.

(Docket A–93–02, Item II–E–9) For

further discussion of the GASOUT code,

see the discussion of air drilling below

in this preamble.

Some commenters stated that DOE

had erroneously excluded from the PA

the stuck pipe 15 and gas erosion 16

spallings mechanisms, two additional

ways by which high gas pressure

conditions in the repository could result

in releases of solid radioactive waste to

the accessible environment. In

particular, commenters asserted that

DOE had selected an incorrect value for

the threshold waste permeability, 17

above which the gas erosion and stuck

pipe mechanisms would not occur.

They also stated that DOE’s assumptions

did not take into consideration the

presence of magnesium oxide (MgO)

backfill, which would affect both waste

permeability and tensile strength. These

commenters suggested that EPA should

do further analysis, should require DOE

to do more analysis, or should reject

DOE’s spallings models and mandate

new models. Other commenters

countered that stuck pipe and gas

erosion would not occur because of the

physical and mechanical properties of

the waste.

The EPA has analyzed the validity of

DOE’s decision to exclude stuck pipe

and gas erosion mechanisms from the

PA. In order for these mechanisms to

occur, there must be a combination of

high gas pressure, low waste

permeability, and low waste strength.

First, the gas pressure in the repository

must be sufficiently high to move waste

to and up the borehole. Low waste

permeability is necessary to maintain

the high pressure during the drilling

event. Finally, low waste tensile

strength is necessary to allow the waste

to break off and move toward the

borehole. The DOE has fabricated

simulated samples of waste that have

corroded or degraded and have

generated gas, as is expected to occur in

the WIPP once waste is emplaced, and

has measured the porosity 18 of these

samples. Waste porosity and gas

pressure are related. This is because a

greater porosity means a greater volume

of spaces that gas can fill. By the ideal

gas law, when the same number of gas

molecules fill a larger volume, they will

have a lower gas pressure. The waste

porosity also affects waste permeability,
27366 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

19 In this discussion, the term ‘‘air drilling’’ refers

to all forms of drilling using drilling substances

lighter than mud.

since more open space in waste means

more space where a liquid or gas can

penetrate. Based upon DOE’s

measurements of the porosity of

surrogate waste samples, EPA found

that it is extremely unlikely that the

required conditions of high gas pressure

and low waste permeability will exist in

the WIPP. The high pressure necessary

to support gas erosion or stuck pipe

mechanisms would expand the WIPP

waste, creating a higher porosity (and

higher permeability). Thus, for the

characteristics of the WIPP waste, the

permeability would not become low

enough (less than 10¥16 square meters)

to create a gas erosion or stuck pipe

event. (Docket A–93–02, Item V–B–2,

CARD 23, Section 7.4) If the

permeability is not low enough for gas

erosion or stuck pipe, releases may still

occur, but the release mechanism will

be a short-lived blowout (spallings)

rather than gas erosion or stuck pipe.

Therefore, EPA concludes that DOE

correctly modeled only the ‘‘blowout’’

process in its spallings model and

appropriately excluded stuck pipe and

gas erosion.

c. Air Drilling. Shortly before

publication of the proposed certification

decision, and after EPA’s cutoff date for

addressing ANPR comments, EPA

received a comment containing a

technical report stating that DOE should

have included the human intrusion

scenario of air drilling in the PA, rather

than screening it out. (Docket A–93–02,

Item IV–D–01) Normally, oil drillers

will use mud in the borehole to reduce

friction and to carry away solids that

break free as the drill bit bores into the

ground. However, in some cases, drillers

might instead use air, mist, foam, dust,

aerated mud or light weight solid

additives as the fluid in the borehole.

Public comments noted that the air

drilling 19 scenario was not included by

DOE in the CCA, and raised the

following issues:

• Air drilling technology is currently

successfully used in the Delaware Basin.

• Air drilling is thought to be a viable

drilling technology under the

hydrological and geological conditions

at the WIPP site.

• Air drilling could result in releases

of radionuclides that are substantially

greater than those considered by DOE in

the CCA.

In response to these concerns, EPA

prepared a study on air drilling and its

likely impact on the WIPP (Docket A–

93–02, Item IV–A–1), placed it in the

docket, and allowed for a public

comment period of 30 days. (63 FR

3863; January 27, 1998) The EPA’s study

examined the frequency of air drilling

near the WIPP, the likelihood that

drillers would use air drilling under the

conditions at the WIPP, and the

potential volume of radioactive waste

that could be released using air drilling.

In the report, the Agency concluded that

air drilling is not a common practice in

the Delaware Basin, and that air drilling

through the Salado, the geologic salt

stratum where the WIPP is located, is

not presently used in the Delaware

Basin near the WIPP. Because the use of

air as a drilling fluid is not current

practice in the Delaware Basin, EPA

found that DOE is not required to

include air drilling in the PA.

(§ 194.33(c)(1)) Nevertheless, the

Agency also modeled potential releases

of radioactive waste during air drilling,

and found that any releases would be

within the range calculated in the CCA

PA for mud-based drilling.

The EPA received a number of

comments on its air drilling report.

Some members of the public stated that

air drilling is a proven technology and

the frequency of its use by the oil and

gas industry is increasing. They

suggested that air drilling techniques are

not currently being used more widely

because of the limited knowledge of

new developments and the industry’s

resistance to changing methods. The

commenters implied that if these

obstacles are overcome, air drilling will

occur widely in the future. One

commenter recommended that the

Agency require DOE to consider air

drilling using a frequency of 30% of all

wells, based upon a projected estimate

from DOE of the use of air drilling in the

entire U.S. in the year 2005. In contrast,

other commenters stated that air drilling

would be less economic than mud

drilling if the driller encountered any

interruption in the air drilling process.

The Agency recognizes that air

drilling is a proven technology for

extraction of oil and gas under

appropriate conditions. However, EPA

believes that it is inappropriate to use

speculative projections of future

practices in the oil and gas industry

across the U.S. in the PA or to guess that

a practice will be used more in the

future because some drillers may

currently misunderstand the

technology. The EPA’s compliance

criteria require DOE to assume that

future drilling practices and technology

will remain consistent with practices in

the Delaware Basin at the time a

compliance application is prepared.

(§ 194.33(c)(1)) The EPA included this

requirement in the compliance criteria

to prevent endless speculation about

future practices, and to model situations

that are representative of the Delaware

Basin, rather than a wider area that is

not representative of conditions at the

WIPP site. (61 FR 5234; Docket A–92–

56, V–C–1, p. 12–12) The Agency chose

to use current drilling practices for

resources exploited in the present and

past as a stand-in for potential future

resource drilling practices. (61 FR 5233)

The specific frequency suggested by the

commenter is arbitrary because it

applies to the entire U.S. rather than the

Delaware Basin and because the

commenter provides no reason for

selecting an estimated frequency of air

drilling in 2005 rather than in some

other year. The DOE must abide by the

requirement of § 194.33(c)(1) to assume

that future drilling practices remain

consistent with practices in the

Delaware Basin at the time the CCA was

prepared (1996). Thus, the pertinent

issues are whether air drilling

constitutes current practice in the

Delaware Basin and, if so, how it could

affect potential releases from the WIPP.

Some commenters said that air

drilling is already occurring in the

Delaware Basin, and thus, should be

considered in the PA. One commenter

noted that EPA should look at the

frequency of air drilling in the Texas

portion of the Delaware Basin, as well

as in the New Mexico portion of the

Delaware Basin, consistent with

§ 194.33(c)(1). Commenters also raised a

concern that EPA’s examination of well

files might underestimate the

occurrence of air drilling because

information on the drilling fluid used is

not always clear in the records. Another

commenter suggested that air drilling

could be left out of the PA only if it has

a probability of less than one chance in

ten thousand, under § 194.32(d).

The EPA agrees that the frequency of

air drilling needs to be examined in the

entire Delaware Basin. In response to

these public comments, EPA

supplemented the analysis in its initial

air drilling report by conducting a

random sample of wells drilled in the

New Mexico and Texas portions of the

Delaware Basin and has determined the

frequency of air drilling in the entire

Delaware Basin. (The initial report is

located at Docket A–93–02, Item IV–A–

1; the supplemented report is located at

Docket A–93–02, Item V–B–29.) The

Agency found that air drilling is not

used more frequently in the Delaware

Basin as a whole than in the New

Mexico portion of the Basin. At the 95%

statistical confidence level, EPA found

that, at most, only 1.65% of all wells in

the Delaware Basin may have been

drilled with air. In those records

examined, none of the wells were
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27367

20 The fluid injection discussed here refers to

either (1) brine disposal from oil activities, (2)

maintenance of pressure in existing oil production,

Continued

drilled through the salt-bearing geologic

formation, as would be required to

penetrate the WIPP. This additional

information confirms the Agency’s

conclusion (as stated initially in Docket

A–93–02, Item IV–A–1) that air drilling

is not a current practice in the Delaware

Basin.

The EPA agrees that the well drilling

records examined in its random sample

may not by themselves be conclusive

about whether air drilling was used at

specific wells. As an independent

confirmation of the extent of air drilling

in the Delaware Basin (and near the

WIPP specifically), EPA also

interviewed knowledgeable industry

contacts, many of whom were

experienced in air drilling. These

individuals independently confirmed

that air drilling is rarely practiced in the

Delaware Basin and that it is virtually

nonexistent in the vicinity of WIPP.

(Docket A–93–02, Item V–B–29) The

DOE also found similar results in an

exhaustive analysis of 3,349 wells in the

Delaware Basin. (Docket A–93–02, IV–

G–7) These independent sources of

information further verify EPA’s

conclusion that air drilling is not a

current practice in the Delaware Basin.

In particular, air drilling through the

salt section (where the waste is present)

is not consistent with current drilling

practices in the Delaware Basin.

The EPA disagrees that the frequency

of air drilling must be less than one in

ten thousand wells in order for DOE to

leave it out of the PA. Section

194.33(c)(1) requires DOE to look at

‘‘drilling practices at the time a

compliance application is prepared.’’

This requirement refers to typical

industry practices in the Delaware Basin

at the time a compliance application is

prepared. (See 61 FR 5230; Docket A–

92–56, Item V–C–1, p. 12–18; Docket A–

93–02, Item II–B–29, p. 50.) It was not

intended to apply to experimental

procedures, emergency procedures, or

conjectured future practices. The

Agency finds it unrealistic to consider a

specific deep drilling method to be

current practice or typical of drilling in

the Delaware Basin when it is used for

only a small percentage of all wells in

the Basin. As indicated in § 194.32,

deep drilling and shallow drilling are

events to be considered in the PA. The

Agency believes that DOE has correctly

implemented the requirements of

§ 194.32(d) by including the general

technique of deep drilling as a scenario

in the PA, rather than separately

analyzing the probability of each

potential kind of deep drilling.

One commenter stated that air drilling

is a viable technique under the

conditions in the vicinity of the WIPP

site. This commenter said that drilling

with air may even become the method

of choice in the WIPP area, since a

driller will prefer to use a technology

such as air drilling, which avoids loss

of circulation. Another commenter

expressed concern about the

conclusions of EPA’s Analysis of Air

Drilling at WIPP (Docket A–93–02, Item

IV–A–1) that water inflow upon drilling

would prevent air drilling near the

WIPP and that air drilling is not an

economically feasible drilling method

near the WIPP. This commenter also

stated that EPA’s estimates of the water

flow rate that can be tolerated during air

drilling were too low.

The EPA examined a report from a

commenter that found that water

inflows from the Culebra would not

prevent air drilling at the WIPP site. The

report based this premise on the

transmissivity in some parts of the WIPP

site. However, EPA disagrees that the

transmissivity threshold mentioned in

the report would provide sufficient

reason to conclude that air drilling was

currently practical in that area. The

range of transmissivities at the WIPP

site shows that air drilling is definitely

not feasible in some parts of the site,

and is unsuitable in other portions of

the site. The EPA also found that the

possibility of excessive water inflow

was only one of the reasons mentioned

by industry contacts as to why air

drilling was not used in the vicinity of

WIPP. Other reasons, cited in EPA’s Air

Drilling Report, include sections of

unconsolidated rock above the salt

section and the potential for hitting

brine pockets in the Castile Formation.

(Docket A–93–02, Item V–B–29)

Because of the reasons industry contacts

gave for not conducting air drilling near

the WIPP, the Agency disagrees that air

drilling would ever become a preferred

method of drilling at the WIPP site.

Commenters were concerned that

there might be greater releases of waste

with air drilling than with mud drilling.

This is because air and foam are less

dense than mud, so it would take less

pressure inside the repository to push

waste toward the surface as solid waste

(spallings) or as waste dissolved in brine

(direct brine release). One individual

calculated spallings releases due to air

drilling using DOE’s GASOUT computer

code, and found that releases due to air

drilling were several orders of

magnitude higher than the releases

computed in the CCA PA. (Docket A–

93–02, Item II–D–120) Other

commenters countered that the

GASOUT code was not designed to

model spallings using air drilling, and

therefore, that the GASOUT code could

not be applied in this situation.

Although EPA concluded that there

was no need to include air drilling in

the PA, the Agency conducted its own

modeling of spallings due to air drilling

to respond to public concerns. (Docket

A–93–02, Item V–B–29, Section 6 and

Appendix A) The EPA used the quasistatic model developed by DOE as a

mechanistic model of spallings, an

approach that provides greater modeling

flexibility than with the GASOUT code.

The quasi-static model tends to

overestimate releases of radioactive

waste because it predicts the total

volume of waste that is available for

transport. The total volume available for

transport would not all be released in

actuality because pressurized gas would

not be able to lift large, heavy particles

up to the earth’s surface. Studies have

shown that the quasi-static model

generally predicts larger spalled

volumes than the model incorporated in

the GASOUT code. (Docket A–93–02,

Item II–G–23, Table 3–3) For air drilling

conditions, EPA estimated volumes of

releases to be within the range of

spallings values predicted by the CCA

and used in the PAVT evaluation.

The EPA also examined the effects of

air drilling on the combined,

complementary cumulative distribution

functions (‘‘CCDFs’’) used to show

graphically whether the WIPP meets

EPA’s containment requirements for

radioactive waste. (Docket A–93–02,

Item V–B–29, Section 6) The EPA found

that the CCDFs produced by DOE were

not significantly different from those

produced in the PAVT. In fact, releases

from the WIPP were still below the

containment requirements of § 191.13

by more than an order of magnitude

when air drilling is included as a

scenario.

The EPA determines that DOE does

not need to include air drilling in the

PA because it is not current practice in

the Delaware Basin. Further analyses,

conducted by EPA solely to allay the

public’s concerns on this issue, showed

that spallings releases calculated in the

CCA and the PAVT encompass the

potential impacts of air drilling (were it

to occur) on compliance with the

containment requirements.

See CARD 32 for further discussion of

the screening of features, events, and

processes. (Docket A–93–02, Item

V–B–2)

d. Fluid Injection Commenters stated

that DOE should not have screened out

the human intrusion scenario of fluid

injection 20 from the final PA
27368 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

or (3) water flooding to increase oil recovery. In the

Delaware Basin, the fluid would most likely be

brine.

21 BRAGFLO predicts gas generation rates, brine

and gas flow, and fracturing within the anhydrite

marker beds in order to calculate the future of the

repository.

calculations. Brine could be injected

into existing boreholes, enter the

repository, become contaminated and

flow to various release points. In

§ 194.32(c), EPA’s compliance criteria

specifically require DOE to analyze the

effects of boreholes or leases that may be

used for fluid injection activities near

the disposal system soon after disposal.

The fluid injection scenario has been

of particular concern to the public

because of events that occurred in the

Rhodes-Yates oil field, about 40 miles

east of WIPP but outside the Delaware

Basin in a different geologic setting. An

oil well operator, Mr. Hartman

encountered a brine blowout in an oil

development well while drilling in the

Salado Formation in the Rhodes-Yates

Field. In subsequent litigation, the court

found that the source of the brine flow

was injection water from a long-term

waterflood borehole located more than a

mile away. A fluid injection scenario

causing the movement of fluid under

high pressure is referred to as ‘‘the

Hartman Scenario’’ after this case.

The DOE initially screened out this

activity from the PA because the

Department’s modeling of fluid

injection indicated that it would result

in brine inflow values within the range

calculated in the CCA PA where there

is no human intrusion. (Docket A–93–

02, Item II–A–32) Both EPA and public

commenters on the Advance Notice of

Proposed Rulemaking did not believe

that DOE had performed sufficient

analyses to rule out the potential effects

of fluid injection related to oil

production on the disposal system.

Therefore, the Agency required DOE to

model fluid injection using more

conservative geologic assumptions

about the ability of Salado anhydrite to

transmit fluid. (Docket A–93–02, Item

II–I–17) This more conservative

modeling showed that fluid injection

would have little impact on the results

of the PA. (Docket A–93–02, Item II–I–

36) Based on this modeling and other

information submitted by DOE on the

frequency of fluid injection well

failures, EPA proposed that DOE’s

screening was sufficient and realistic.

(62 FR 58806, 58822) Thus, EPA

concluded that fluid injection could be

screened out of the final PA calculations

based on low consequences to the

disposal system.

The EPA performed its own

independent review of fluid injection,

which showed that the injection

analysis must include the nature of

anhydrites, duration of injection

activities, and presence of leaking

boreholes. (Docket A–93–02, Item V–B–

22) As part of its analysis, the Agency

performed additional modeling of the

injection well scenario. The EPA

concluded that, although scenarios can

be constructed that move fluid to the

repository via injection, the probability

of such an occurrence, given the

necessary combination of natural and

human-induced events, is very low.

Several commenters stated that either

EPA or DOE needed to model the

Hartman Scenario. One commenter

stated that it should be proven that

DOE’s BRAGFLO 21 code can reproduce

what is believed to have happened in

the Hartman case. Some members of the

public also referred to modeling

performed by Bredehoeft and by

Bredehoeft and Gerstle which found

that the Hartman scenario could cause

releases in excess of the disposal

regulations (Docket A–93–02, Item II–D–

116 Attachment (b)); these commenters

stated that neither EPA nor DOE had

satisfactorily modeled the Hartman

Scenario.

The EPA examined Bredehoeft and

Gerstle’s modeling of fluid injection at

the WIPP and finds their assumptions

highly unrealistic. In particular, the

report assumes that all brine is directly

injected into one anhydrite interbed in

the Salado Formation. The anhydrite

interbeds in the Salado are only a few

feet thick. Therefore, a driller would

need to plan specifically to deliberately

inject brine into the anhydrite interbeds

to have such a situation occur at the

WIPP. Also, well operators using fluid

injection for oil or gas recovery would

be attempting to inject brine into

formations where petroleum and gas

reserves are found, which are thousands

of feet below the Salado. If flooding due

to fluid injection occurred accidentally

in the vicinity of the WIPP, the flow of

fluid would not be limited to the narrow

band of one anhydrite interbed in the

Salado. Also, Bredehoeft and Gerstle’s

report assumes that fractures in the

anhydrite will extend for three or more

kilometers and will remain open. This

would require extremely high pressures

to be generated by the brine injection

process. The EPA agrees that under very

unrealistic conditions, modeling can

show fluid movement toward the WIPP

under an injection scenario. However,

when using more realistic but still

conservative assumptions in the

modeling, fluid movement sufficient to

mobilize radioactive waste in the

disposal system does not occur.

In response to public comments, the

Agency tried to reproduce several of the

results obtained with Bredehoeft’s

model using DOE’s BRAGFLO model. In

two cases, EPA’s modeling produced

flows similar to those in the March 1997

Bredehoeft report. (Docket A–93–02,

Item II–D–116) However, because the

Agency’s study looked at flows in

multiple locations and Bredehoeft’s

study does not specify the location of its

predicted flows, the results are not

directly comparable. The EPA also

attempted to replicate Bredehoeft’s

modeling of high pressure conditions

that would be mostly likely to cause a

catastrophic event. However, the

Agency found that critical aspects of

Bredehoeft’s work are not documented

sufficiently to make meaningful

comparisons using the BRAGFLO

computer code. In particular, the grid

spacing used in the model predictions

were unclear. This information is

necessary in order to recreate

Bredehoeft’s simulation. Also, EPA was

unable to determine whether the length

to which fractures grow are based on

completely opened or partially opened

fractures. The Agency contacted the

primary author of the paper in order to

obtain additional critical information.

However, the author was not certain

how they had treated these aspects of

modeling and had no further

documentation. (Docket A–93–02, Item

IV–E–23) Because of insufficient

documentation of vital aspects of

modeling, the Agency could not

replicate Bredehoeft’s results. In

addition, due to lack of proper

documentation it was not clear to EPA

that Bredehoeft’s modeling represented

the Hartman Scenario. Therefore, EPA

finds that lack of agreement between the

Bredehoeft model and BRAGFLO does

not indicate that DOE’s modeling is

inadequate. (Docket A–93–02, Item V–

B–22)

Several commenters had concerns

about EPA’s Fluid Injection Analysis,

including its conclusions that the

geology and the current well

construction practices near the WIPP are

extremely different from the geology

and well construction practices that

occurred in the Hartman case. In

contrast, other commenters stated that

fluid injection is unlikely to occur near

WIPP and current well construction

practices in the area will prevent

injection well leakage. Some

commented that EPA’s probability

estimates for the chain of events that

could lead to a blowout caused by fluid

injection were overly optimistic and

that the probability estimate ignores
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27369

experience with severe water flows in

New Mexico.

The EPA concluded that current well

construction practice makes it unlikely

that there could be a well failure of the

nature of the ‘‘Hartman scenario’’ that

occurred in the Rhodes-Yates field

outside the Delaware Basin. This is

because regulatory requirements for

drilling are much more rigorous near the

WIPP than was the case at the RhodesYates field at the time of the Hartman

case. Also, the Agency reiterates that

there are significant differences in the

geology near the WIPP and in the

Rhodes-Yates field where the Hartman

case occurred, that should not be

ignored. The vertical distance between

the formation where brine would be

injected for disposal and the formation

where the repository is located is greater

than the vertical distance that fluid is

believed to have traveled in the

Hartman case. This distance, and effects

of friction, would make it more difficult

for fluids to travel vertically upward at

the WIPP than in the Hartman case.

Interbeds near the WIPP site are more

numerous and are likely to be thinner

than in the Hartman case, thereby

reducing the likelihood of flow between

the repository and the WIPP boundary.

The Agency concludes that the geology

in the WIPP area will play an active role

in reducing fluid movement, or in an

extreme case, preventing a massive well

blowout. (Docket A–93–02, Item V–B–

22)

While EPA accepted DOE’s argument

that the fluid injection scenario can be

screened out of the PA on the basis of

low consequence, DOE presented

supplemental information that also

indicated that the probability of a

catastrophic well failure would be low.

The EPA’s Fluid Injection Analysis for

the proposed rule also examined the

chain of events necessary to cause

catastrophic failure for a well. The EPA

estimated that the probability of this

chain of events occurring for a given

well in the vicinity of the WIPP was

low’within the range of one in 56,889 to

one in 667 million. (Docket A–93–02,

Item III–B–22) These estimates of

probability were intended to illustrate

in this hypothetical failure scenario the

chain of events that must all occur for

an injection well to impact the WIPP.

The commenters objected to the lowest

probability estimate, but did not state

which probabilities or assumptions in

the chain of events that they believed

EPA had incorrectly selected. The EPA

notes that this estimate of low

probability was only one of many

reasons cited in the technical support

document for EPA’s proposed

determination that fluid injection could

be screened from the PA. (Docket A–93–

02, Item III–B–22) After considering

geologic information, well history and

age, construction standards, and

operating practices, the Agency

concludes that reported water flows in

the Salado Formation in other areas of

New Mexico are not representative of

conditions in the vicinity of the WIPP.

(Docket A–93–02, Item V–B–22) Even if

an injection event takes place, the

predicted low consequence is sufficient

reason to remove it from consideration

in the PA.

One commenter stated that EPA

should require DOE to revise its PA

model to include the Hartman Scenario

and perform another PA. In contrast,

another commenter stated that fluid

injection events will not impact

repository performance, even with

conservative assumptions, so fluid

injection can be excluded from the PA.

The Agency finds that:

• Commenters’ modeling of fluid

injection that predicted potential

releases exceeding EPA standards was

based upon unrealistic assumptions that

would maximize releases.

• The EPA tried to replicate scenarios

similar to the Hartman case using DOE’s

BRAGFLO model. Some results were

similar in magnitude to modeling

results presented by commenters, but

not directly comparable.

• Modeling by DOE predicts that

fluid injection will cause low flows that

will not significantly impact the results

of PA.

• Well construction procedures near

the WIPP have changed due to

regulatory requirements; therefore, it is

unreasonable to assume that the same

well procedures from the Hartman case

will occur near the WIPP.

• There are significant geological

differences between the WIPP site and

the Rhodes-Yates field in the Hartman

case.

For all of these reasons, EPA

concludes that it is not necessary to

repeat the PA using the scenario of fluid

injection. (Docket A–93–02, Item V–B–

22; Also, see Docket A–93–02, Item V–

B–2, CARDs 23 and 32 for further

discussion of fluid injection.)

A related issue raised by commenters

was DOE’s modeling of fractures in the

anhydrite interbeds directly above the

WIPP. Such fractures could allow

injected brine to enter the repository, to

dissolve waste, and to release

radioactivity outside the WIPP.

Commenters stated that DOE’s model for

anhydrite fracturing was inadequate to

describe observed changes at the WIPP

and was not based on sufficient

experimental data. Some commenters

stated that DOE’s model significantly

understates the length of fractures

compared to another modeling

technique, Linear Elastic Fracture

Mechanics (‘‘LEFM’’). Shorter fractures

would mean that contaminated brine

does not travel as easily, which lessens

releases.

The Agency disagrees that DOE’s

modeling of anhydrite fracturing is

inadequate. The independent

Conceptual Models Peer Review Panel

found that the ‘‘type of fracture

propagation and dilation used in the

conceptual model has been

substantiated by in situ tests.’’ The

Panel also found that the conceptual

model was adequate. (Docket A–93–02,

Item II–G–1, Appendix PEER.1) The

EPA finds that the mathematical

‘‘porosity model’’ used in the CCA PA

adequately implements the conceptual

model for anhydrite fracturing. This

mathematical model used a combination

of field test data at lower pressures and

the theory of continuum mechanics at

higher pressures.

Some features of LEFM are not

appropriate for representing the

anhydrite interbeds. LEFM predicts that

a single, long fracture hundreds of feet

long will be created in a homogeneous

medium. The Agency finds that this

approach is inappropriate for the

anhydrite interbeds in the Salado at the

WIPP, which already contain numerous

small fractures. (Docket A–93–02, Item

IV–G–34, Attachment 5; Item V–C–1,

Section 194.23) Field tests found that

fractures branched into a series of

fractures following preexisting fractures

or weaknesses near the injection hole,

rather than producing a single, longdistance fracture. In the case of fluid

injection, these fractures would store

fluid, which would slow down and

shorten further fractures. The preexisting fractures will produce a fracture

front, such as that modeled by

BRAGFLO, rather than a single fracture

radius, as modeled by an LEFM. Two

studies cited by commenters as support

for use of LEFM in fact question the

applicability of LEFM to WIPP

anhydrites and recommend that DOE

consider alternative conceptual models.

(e.g., Docket A–93–02, Item IV–G–38)

The EPA concludes that BRAGFLO is

more appropriate to use for WIPP than

a pure linear elastic fracture mechanics

model because there are pre-existing

fractures in the anhydrite layers that

must be accounted for in the conceptual

model. The EPA finds that the

conceptual model based on a single

fracture is fundamentally flawed for

application in WIPP anhydrites. The

Agency also finds that the model

incorporated in the PA is appropriate,
27370 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

and that further modeling with revised

computer codes is not necessary.

e. Potash Mining. Public comments

raised concerns about DOE’s estimates

of the potash reserves in the vicinity of

the WIPP and DOE’s evaluation of the

solution mining scenario. The primary

effects that mining could have on the

repository are opening existing fractures

in the geologic formations above the

WIPP and increasing hydraulic

conductivity as a result of subsidence.

These effects could change the flow and

path of ground water through the

Culebra dolomite.

Several commenters stated that DOE

underestimated the amount of potash in

the vicinity of the WIPP and therefore

underestimated the impact that

extracting the additional potash would

have on the performance of the

repository. In the CCA, DOE provided

estimates of the mineable potash

reserves both outside and within the

WIPP Land Withdrawal Area. The

compliance criteria require DOE to

consider excavation mining of only

those mineral resources which are

extracted in the Delaware Basin.

(§ 194.32(b)) Therefore, potash resources

of a type or quality that are currently not

mineable for either technological or

economic reasons need not be addressed

in DOE’s analysis. The EPA determined,

through an independent analysis, that

the CCA appropriately represents the

extent of currently mined resources, in

accordance with the criteria. The EPA

also determined that DOE appropriately

considered the impact that such

resources and excavation mining could

have on the performance of the

repository. (Docket A–93–02, Item V–B–

2, CARD 32)

Additional comments were received

on DOE’s screening of solution mining

from the PA. The DOE determined that

solution mining of potash is not

occurring in the vicinity of the WIPP

and can be omitted from the PA based

on the regulatory requirement that only

currently occurring (or near-future)

practices be considered in the PA.

(§ 194.32(c)) The EPA agrees with DOE

that solution mining is not a current

practice and can be omitted from the PA

on regulatory grounds.

The DOE submitted supplemental

information which related to the

potential effects of solution mining for

potash. (Docket A–93–02, Item II–I–31)

The DOE concluded that the impacts of

solution mining for potash would be the

same as those for room and pillar

mining, and that the potential

subsidence-induced hydraulic effects in

the Culebra would be similar to those

for typical mining practices. Some

comments disputed this conclusion,

stating that the effects of solution

mining on the repository would be

substantially different than those from

conventional mining and could cause

the WIPP to exceed the containment

requirements. After examining these

comments, EPA concluded that the

scenarios set forth in the comments

were not realistic and that the

commenter’s conclusion was based on

an extreme example of subsidence from

solution mining. The EPA disagrees

with the comments and concludes that

subsidence in the vicinity of the WIPP

would not vary significantly with

solution mining compared to

conventional mining.

The EPA concludes that solution

mining for potash is appropriately

omitted from the PA because it is not a

current practice, and therefore, is not an

activity expected to occur prior to or

soon after disposal. As added assurance,

the Agency also finds that even if

solution mining of potash were to occur

in the vicinity of the WIPP, the potential

effects of such mining are consistent

with those from conventional

techniques and are therefore already

accounted for in the PA. (Docket A–93–

02, Item V–C–1, Section 8)

f. Carbon Dioxide Injection. Public

comments raised concerns that carbon

dioxide (CO2) injection is a current

drilling practice in the Delaware Basin

that DOE inappropriately omitted from

the PA calculations. Carbon dioxide

flooding is the injection of CO2 into an

oil reservoir to improve recovery. CO2

injection is typically used in tertiary

recovery processes after the economic

limits for waterflooding have been

reached. When CO2 is injected and

mixing occurs, the viscosity of the crude

oil in the reservoir is reduced. The CO2

increases the bulk and relative

permeability of the oil, and increases

reservoir pressure so that the resulting

mixture flows more readily toward the

production wells. When CO2 begins to

appear at the producing well, it is

typically recovered, cleaned of

impurities, pressurized and re-injected.

The use of CO2 flooding for enhanced

oil recovery in west Texas and southern

New Mexico began in 1972. In this area,

most CO2 injection activity is located on

the Central Basin Platform and on the

Northwest Shelf. A limited number of

CO2 flooding projects have occurred in

the Texas portion of the Delaware Basin.

Economy of scale, oil prices, proximity

to CO2 supply and reservoir

heterogeneity are several of the

controlling factors that strongly

influence whether this technique is

applied at a given well. (Docket A–93–

02, Item V–C–1, Section 8)

In the CCA (Appendix SCR), DOE

determined that CO2 injection is not a

current drilling practice in the Delaware

Basin and therefore omitted it from

consideration in the PA. For the

proposed rule, EPA concurred with DOE

that CO2 injection was not a current

practice. However, as a result of the

public comments, EPA reviewed the

issue and determined that CO2 injection

does occur in the Texas portion of the

Delaware Basin. In responding to

comments, EPA found no evidence of

CO2 injection practices in the New

Mexico portion of the Delaware Basin.

(Docket A–93–02, Item V–C–1, Section

8) All CO2 injection projects found in

New Mexico occurred outside the

Delaware Basin. The EPA found that

CO2 injection has only limited potential

for use around WIPP because of sitespecific concerns related to reservoir

size, proximity to existing pipelines and

reservoir heterogeneity. However,

because EPA confirmed that CO2

injection is practiced in the Delaware

Basin, EPA conducted an analysis of the

consequences that CO2 injection could

have on the PA calculations.

In order to investigate the potential

effect of CO2 injection should it occur in

the future, EPA conducted some

bounding calculations. (Docket A–93–

02, Item V–C–1, Section 8) Using

numerous conservative assumptions,

EPA estimated the rate of CO2 flow

through a hypothetical wellbore

annulus into an anhydrite interbed at

the depth of the WIPP repository. For

example, grout in the wellbore annulus

is expected to degrade only along

portions of the wellbore; however, EPA

assumed that such degradation would

occur along the entire wellbore, thus

providing a continuous pathway for CO2

migration. Other conservative

assumptions included a long time frame

for injection, constant CO2 pressures at

the point of injection and at the

intersection of the interbed with the

borehole, and a high permeability in the

interbed. The EPA’s calculations also

assumed that CO2 would be injected

into the Delaware Mountain Group

below WIPP and readily migrate to

Marker Bed 139, through which CO2 is

assumed to flow toward the repository.

These assumptions increase the

potential effect of the gas injection and

therefore increase the predicted

radionuclide releases that are calculated

for the performance of the WIPP

repository.

These simple but conservative

calculations for a hypothetical CO2

flood indicate that, even if it were to

occur, CO2 injection does not pose a

threat to WIPP. For the very

conservative assumptions specified in
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27371

this study, even for long periods of time,

there is little potential for injected CO2

to ever reach the repository. In

summary, DOE determined that CO2

injection was not a current drilling

practice in the Delaware Basin and

therefore screened it from the PA based

on regulatory requirements. Based on

public comments, EPA identified

limited CO2 injection activities in the

Delaware Basin. The EPA conducted an

analysis of the effects of CO2 injection

on the repository and found that CO2

injection can be omitted from the PA

because of the minimal consequences

that would occur as a result of CO2

injection.

g. Other Drilling Issues. A few public

comments raised concerns about other

human intrusion related scenarios. For

example, some comments disagreed

with the drilling rates that were set forth

in the CCA. Other comments contended

that natural gas storage exists in the

Delaware Basin and should be

considered in the PA.

Several public comments stated that

the CCA did not provide drilling rates

that are consistent with the extensive

drilling throughout the area. The EPA

required DOE to include the effects of

drilling into a WIPP waste panel in the

PA. The DOE was required to separately

examine the rate of shallow and deep

drilling. Shallow drilling is defined in

§ 194.2 as drilling events that do not

reach a depth of 2,150 feet below the

surface and therefore do not reach the

depth of the WIPP repository. Deep

drilling is defined in § 194.2 as drilling

events that reach or exceed the depth of

2,150 feet and therefore reach or exceed

the depth of the repository. Both types

of drilling events include exploratory

and developmental wells. (See Docket

A–93–02, Item V–B–2, CARD 33 for

further discussion of drilling rates.)

The EPA accepted DOE’s finding that

shallow drilling would not be of

consequence to repository performance

and was therefore not included in the

PA. (Docket A–93–02, Item V–B–2,

CARD 32, Section 32.G) The future rate

of deep drilling was considered in

DOE’s PA. The deep drilling rate set

forth in the CCA for the Delaware Basin

is 46.775 boreholes per square kilometer

per 10,000 years.

Several commenters suggested that

DOE should use other, higher deep

drilling rates in the PA. Comments

stated that these higher rates, based on

drilling over limited areas near the

WIPP or on time periods shorter than

100 years (such as the last year or the

last 50 years), would be more consistent

with current drilling rates. The EPA’s

criteria require that the deep drilling

rate be based on drilling in the Delaware

Basin over the 100-year period

immediately prior to the time that the

compliance application is prepared.

(§ 194.33(b)(3)) Although the drilling

rate dictated by EPA’s requirements may

be lower than the current drilling rate,

the use of a 100-year drilling rate more

adequately reflects the actual drilling

that may be expected to take place over

the long term. (See Response to

Comments for 40 CFR Part 194, Docket

A–92–56, Item V–C–1, p. 12–11.) The

future rate of deep drilling in the PA

was set equal to the average rate at

which that type of drilling has occurred

in the Delaware Basin during the 100-

year period immediately prior to the

time that the compliance application

was prepared. Commenters did not

suggest that DOE had failed to include

known drilling events or had calculated

the rate inconsistently with EPA’s

requirements. Therefore, EPA finds that

the approach taken by DOE meets the

regulatory requirements set forth in

§ 194.33(b). (Docket A–93–02, Item V–

B–2, CARD 33)

Natural gas storage facilities, in

underground cavities, are known to

exist in the Salado Formation outside

the Delaware Basin. However, neither

EPA nor DOE is aware of any natural gas

storage in the Salado Formation of the

Delaware Basin. Because there is no

known gas storage in the Delaware

Basin, DOE is permitted to omit it from

the PA according to the requirements of

§ 194.32(c).

In addition to determining that there

is no known gas storage in the Delaware

Basin, EPA conducted an analysis of the

effects that this activity would have on

the repository. The EPA’s analysis,

presented in the response to comments,

shows that natural gas storage would

not affect the ability of the WIPP

repository to successfully isolate waste

because the migration potential of the

gas would be minimal.

3. Geological Scenarios and Disposal

System Characteristics

a. Introduction. 40 CFR 194.14(a)

requires DOE to describe the natural and

engineered features that may affect the

performance of the disposal system.

Among the features specifically required

to be described are potential pathways

for transport of waste to the accessible

environment. This information is

crucial to the conceptual models and

computer modeling that is done to

determine compliance with the

containment requirements and the

individual and ground-water protection

requirements. In addition to a general

understanding of the site, EPA required

specific information on hydrologic

characteristics with emphasis on brine

pockets, anhydrite interbeds, and

potential pathways for transport of

waste. The EPA also required DOE to

project how geophysical, hydrogeologic

and geochemical conditions of the

disposal system would change due to

the presence of waste. Geology also

relates to criteria at §§ 194.32 and

194.23, which require DOE to model

processes which may affect the disposal

system, and to use models that

reasonably represent possible future

states of the disposal system.

The EPA examined the CCA and the

supplemental information provided by

DOE and proposed to find that it

contained an adequate description of

the WIPP geology, geophysics,

hydrogeology, hydrology and

geochemistry of the WIPP disposal

system and its vicinity, and how these

conditions change over time. (62 FR

58798–58800) Several commenters

suggested that the WIPP site geology

and disposal system characteristics have

been incorrectly assessed or

inaccurately modeled. Commenters

expressed concern with the WIPP site

regarding Rustler recharge; dissolution,

including karst; presence of brine in the

Salado; use of two dimensional

modeling with the BRAGFLO computer

code instead of modeling the disposal

system using a three-dimensional

representation (2D/3D BRAGFLO),

earthquakes, and the gas generation

conceptual model. The EPA’s response

to these comments is discussed below.

b. WIPP Geology Overview. The WIPP

is located in the Delaware Basin of New

Mexico and Texas and is approximately

26 miles southeast of Carlsbad, New

Mexico. This area of New Mexico is

currently arid, but potential future

precipitation increases were accounted

for in the PA. The Delaware Basin

contains thick sedimentary deposits

(over 15,000 feet, or 4572 meters, thick)

that overlay metamorphic and igneous

rock (1.1 to 1.5 billion years old). The

WIPP repository is a mine constructed

approximately 2,150 feet (655 meters)

below ground surface in the Permian

age (6200–250 million years old) Salado

Formation, which is composed

primarily of salt (halite).

The DOE considered the primary

geologic units of concern to be (from

below the repository to the surface): (1)

the Castile Formation (‘‘Castile’’),

consisting of anhydrite and halite with

pressurized brine pockets found locally

throughout the vicinity of the WIPP site;

(2) the Salado Formation (‘‘Salado’’),

consisting primarily of halite with some

anhydrite interbeds and accessory

minerals and approximately 2,000 feet

(600 meters) thick; (3) the Rustler

Formation (‘‘Rustler’’), containing salt,
27372 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

anhydrite, clastics, and carbonates

(primarily dolomite), with the Culebra

dolomite member of the Rustler as the

unit of most interest; and (4) the Dewey

Lake Red Beds Formation (‘‘Dewey

Lake’’), consisting of sandstone,

siltstone and silty claystone. The

geologic formations below these were

included in the screening of features,

events, and processes, but were not

included in the PA calculations because

they did not affect the performance of

the disposal system. See CARD 32,

Sections 32.A and 32.F, for a detailed

discussion of screening of features,

events, and processes. (Docket A–93–02,

Item V–B–2)

c. Rustler Recharge. Numerous

comments on the proposed rule were

related to whether the Rustler

Formation, primarily the Culebra

dolomite member, would be recharged;

that is, whether water will infiltrate

through the soil and underlying rock

and into the Culebra. Commenters

linked high infiltration to the potential

dissolution of the Culebra and other

members of the Rustler, concluding that

karst has been formed and contributes to

ground water flow. Commenters

claimed that the presence of karst

features would render DOE’s ground

water flow models invalid. Site

characterization data and DOE’s ground

water modeling indicate that infiltration

is very low and limited, if any,

dissolution is ongoing, contrary to

commenters statements.

The DOE indicated that the units

above the Salado (i.e., the Rustler, the

Dewey Lake and the Santa Rosa) are

classified as a single hydrostratigraphic

unit (i.e., equivalent to a geologic unit

but for ground water flow) for

conceptual and computer modeling. The

Rustler is of particular importance for

WIPP because it contains the most

transmissive units above the repository

(i.e., has the highest potential rate of

ground water flow). In particular, the

Culebra dolomite member of the Rustler

Formation is considered to be the

primary ground water pathway for

radionuclides because it has the fastest

ground water flow in the Rustler

Formation. The Culebra dolomite is

conceptualized as a confined aquifer in

which the water flowing in the Culebra

is distinct from rock units above or

below it and interacts very slowly with

other rock units. In general, fluid flow

in the Rustler is characterized by DOE

as exhibiting very slow vertical leakage

through confining layers and faster

lateral flow in conductive units. (Docket

A–93–02, Item V–B–2, CARD 14,

Sections 14.B.4 and 14.B.5) The DOE

stated that the Culebra member

conceptually acts as a ‘‘drain’’ for the

units around it, but that it takes up to

thousands of years for the Culebra to

respond to changes in the environment.

DOE’s modeling indicates that the

Culebra ground water is still responding

to changes in precipitation from the

latest ice age. DOE’s explanation for the

ground water flow in the units above the

Salado is embodied in the ground water

basin model which was introduced in

Chapter 2 of the CCA. The EPA did not

consider treatment of this issue in the

CCA to be adequate and requested

additional information. (Docket A–93–

02, Item II–I–17) The DOE provided

additional information in response to

this request. (Docket A–93–02, Item II–

I–31)

The ground water basin model, which

simulates recharge passing slowly

through the overlying strata before

reaching the portion of the Culebra

within the boundaries of the WIPP site

recognizes the possibility of localized

infiltration. (Docket A–93–02, Item V–

B–2, CARD 23) The DOE included

ground water recharge in its ground

water basin modeling for the Culebra

Member of the Rustler formation. The

DOE also acknowledged the waterbearing capabilities of the Dewey Lake

and considered this possibility in the

PA evaluations. The DOE assumed that

the water table would rise in response

to increased recharge caused by up to

twice the current site precipitation.

Essentially, DOE’s conceptual model

of flow in the Culebra assumes that the

Culebra is a confined aquifer in which

the flow slowly changes directions over

time, depending on climatic conditions.

The ground water basin model also

accounts for the current ground water

chemistry. Current geochemical

conditions are the result of past climatic

regimes and ground water responses to

those changes; because the ground water

chemistry is still adjusting to the current

conditions, it does not reflect the

current ground water flow direction in

the Culebra. This new interpretation

allows for limited but very slow vertical

infiltration to the Culebra through

overlying beds, although the primary

source of ground water will be lateral

flow from the north of the site. The EPA

reviewed DOE’s conceptualization of

ground water flow and recharge, and

believes that it provides a realistic

representation of site conditions

because it plausibly accounts for the

inconsistencies in the current ground

water flow directions and the

geochemistry. The EPA examined this

treatment of recharge in the PA

modeling and determined it to be an

appropriate approach that reasonably

bounds and accounts for the impact of

potential future recharge. (See Docket

A–93–02, Item V–B–2, CARD 14,

Sections 14.B.4 and 14.B.5; CARD 23,

Section 2.4; and CARD 32, Section

32.F.4 for detailed discussions of

hydrogeology.)

Commenters also stated that DOE’s

estimate of the age of ground water is

based on an unreliable methodology and

that the stable isotopic compositions of

most samples of ground water from the

Rustler Formation were found to be

similar to the composition of other,

verifiably young, ground water in the

area. The age of the ground water is

important because the ground water

basin model is based on the assumption

that the Rustler water is ‘‘fossil’’ water,

having been recharged under climatic

conditions significantly different from

the present. Because the isotopic data

can be interpreted differently, EPA

examined the entire spectrum of data

that could be used to assess infiltration

rates, including DOE’s ground water

basin model, Carbon-14 data, and

tritium data. Based on these data, EPA

concluded that the ground water basin

model provides a plausible description

of ground water conditions in the

Culebra. The EPA also points out that

recent Carbon-14 data indicate that a

minimum age of 13,000 years is

appropriate for Culebra waters. Further,

different geochemical zones in the WIPP

are explained by differences in regional

recharge and long residence time.

(Docket A–93–02, Item II–I–31) The EPA

examined all data pertaining to ground

water flow in the Rustler, and believes

the DOE’s total conceptualization

adequately described system behavior

for the purposes of the PA.

d. Dissolution. In the CCA, DOE

indicated that the major geologic

process in the vicinity of the WIPP is

dissolution. The DOE proposed that

three principal dissolution mechanisms

may occur in the Delaware Basin:

lateral, deep and shallow. (Docket A–

93–02, Item V–B–2, CARD 14, section

14.B.4) Deep dissolution refers to that at

the base of or within the salt section

along the Bell Canyon Castile

Formation; lateral dissolution occurs

within the geological units above the

Salado (progressing eastward from Nash

Draw); and shallow dissolution,

including the development of karst and

dissolution of fracture fill in Salado

marker beds and the Rustler, would

occur from surface-down infiltration of

undersaturated water. Lateral, stratabound dissolution can occur without

shallow dissolution from above.

To the west, the slight dip in the beds

has exposed the Salado to near-surface

dissolution processes; however, DOE

estimated that the dissolution front will

not reach the WIPP site for hundreds of
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27373

thousands of years. Near-surface

dissolution of evaporitic rocks (e.g.,

gypsum) has created karst topography

west of the WIPP site, but DOE

contended that karst processes do not

appear to have affected the rocks within

the WIPP site itself. The DOE indicated

that while deep dissolution has

occurred in the Delaware Basin, the

process of deep dissolution would not

occur at such a rate near the WIPP that

it would impact the waste containment

capabilities of the WIPP during the

regulatory time period. The DOE

concluded that the potential for

significant fluid migration to occur

through most of these pathways is low.

However, DOE also concluded that fluid

migration could occur within the

Rustler and Salado anhydrite marker

beds and included this possibility in PA

calculations. In the proposed rule, EPA

concluded that deep, lateral, and

shallow dissolution (including karst

features and breccia pipes) will not

serve as significant potential

radionuclide pathways and that the

potential for significant fracture-fill

dissolution during the regulatory time

period is low. (Docket A–93–02, Item V–

B–2, CARD 14, Section 14.B.5; Item V–

B–3, Section B.3.t)

Comments on the proposed rule

stated that shallow dissolution and karst

features occur at WIPP and will affect its

containment capabilities. The EPA does

not agree with DOE’s assertion that the

distribution of salt in the Rustler is

solely a depositional feature because

Rustler transmissivity (which is related

to fracture occurrence in the Rustler)

corresponds somewhat to the

occurrence of salt in the Rustler. This

implies that some post-Rustler

dissolution has occurred which impacts

the fracturing in Rustler rocks. However,

the evidence observed by EPA indicate

many Rustler features were formed

millions of years ago (e.g., the breccia

zone in the exhaust shaft, or at WIPP–

18, where anhydrite/clay-rich strata may

be halite dissolution residues). Other

Rustler features (e.g., salt distribution in

the Rustler) could have occurred

sometime after the Rustler was

deposited, but there is no evidence to

indicate that ongoing dissolution of

soluble material in the Rustler or at the

Rustler-Salado contact will modify the

existing transmissivity to the extent that

the results of PA will be affected.

(Docket A–93–02, Item V–B–2, CARD

14, Section 14.B.5)

The EPA concurs that the presence of

fractures and related fracture fill that

could be attributed to dissolution or

precipitation could significantly impact

ground water transport in the Rustler.

The DOE modeled the presence of

fractures using a dual porosity model,

and has accounted for permeability

variability by developing transmissivity

fields based upon measured field data

which reflect the varying transmissivity

values. This dual porosity conceptual

model recognizes that fluid may flow

through both the rock matrix and

fractures at the site. The use of dual

porosity assumes ground water flows

through fractures, but allows solutes to

diffuse into the matrix. The EPA

concludes that while fractures are

present in Rustler Formation units and

slow vertical infiltration does occur,

there is no evidence that indicates

fractures are conduits for immediate

dissolution of Rustler or Salado salts, or

that pervasive infiltration and

subsequent dissolution of the Salado

Formation or Rustler is a rapid, ongoing

occurrence at the WIPP site. Further,

ground water quality differences

between the more permeable units of

the Rustler Formation support relative

hydrologic isolation (i.e., the water in

the Magenta member interacts very little

with the water in the Culebra member),

or at least they support very slow

vertical infiltration that has not allowed

for extensive geochemical mixing of

ground waters in these units.

Many commenters suggested that

WIPP cannot contain radionuclides

because WIPP is in a region of karst

(topography created by the dissolution

of rock). Karst terrain typically exhibits

cavernous flow, blind streams, and

potential for channel development that

would enhance fluid and contaminant

migration. Numerous geologic

investigations have been conducted in

the vicinity and across the WIPP site to

assess the occurrence of dissolution

(karst) and the presence of dissolutionrelated features. The EPA reviewed

information and comments submitted

by DOE, stakeholders, and other

members of the public regarding the

occurrence and development of karst at

the WIPP. (Docket A–93–02, Item V–B–

2, CARD 14, section 14.B.5) The EPA

acknowledges that karst terrain is

present in the vicinity of the WIPP site

boundary near the surface. Near-surface

dissolution of evaporitic rocks (e.g.,

gypsum) have created karst topography

west of the WIPP site. Nash Draw,

which (at its closest to WIPP) is

approximately one mile west of the

WIPP site, is attributed to shallow

dissolution and contains karst features.

(Docket A–93–02, Item V–B–3, Section

B.3.t) The EPA also recognizes the

potential importance of karst

development on fluid migration.

The EPA agrees that karst features

occur in the WIPP area but concluded

that karst features are not pervasive over

the disposal system itself. The EPA

examined hydrogeologic data (e.g.,

transmissivity and tracer tests) from

DOE’s wells at and near the WIPP site

and found no evidence of cavernous

ground water flow typical of karst

terrain at the WIPP site. Similarly, a

field investigation conducted by EPA

during the summer of 1990 to assess the

occurrence of karst features showed no

evidence of significant karst features,

such as large channels, dolines,

sinkholes, or collapsed breccias (other

than those at, for example, at WIPP–33

and Nash Draw) in the immediate WIPP

vicinity. (55 FR 47714) Available data

suggest that dissolution-related features

occur in the immediate WIPP area (e.g.,

WIPP–33 west of the WIPP site), but

these features are not pervasive and are

not associated with any identified

preferential ground water flow paths or

anomalies at the WIPP site. (Docket A–

93–02, Item V–B–2, CARD 14, Section

14.B.5) Therefore, the groundwater

modeling in the PA is adequate.

Several commenters stated that poor

Rustler Formation core recovery at

WIPP indicates the presence of karst.

The commenters state that fragmented

core samples containing dissolution

residues are a clear indication of

unconsolidated or cavernous zones

capable of transmitting water with little

resistance. However, core recovery is

related to rock strength, and does not

necessarily have an association with

local hydrologic conditions. In the case

of WIPP, cores that were attempted

through fractured material, including

the Culebra, exhibited poor recoveries.

The EPA agrees that fractured Rustler is

′present at test well H–3. However, EPA

does not believe that the presence of

fractured material in the Rustler

indicates that karst processes are active.

In fact, the development of fractures can

occur for various reasons unrelated to

dissolution (e.g., removal of overlying

rock due to erosion). The DOE

recognized the presence of fractures

within the Culebra, and included this

dual porosity system in the PA

modeling. In addition, core loss is a

common occurrence in the drilling of all

kinds of rocks, sometimes associated

with fracture and other causes related to

drilling technology, as well as the

occurrence of soft or incompetent rock.

The EPA concludes that to interpret all

zones of lost core as zones of karst is

inappropriate, as other rock features

contribute to core loss which have

nothing to do with cavernous porosity.

The EPA reviewed information

pertinent to the potential development

of karst in the WIPP area and believes

that the near continuous presence of the

more than half-million year old
27374 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

Mescalero Caliche over the WIPP site is

a critical indicator that recharge from

the ground surface to the bedrock

hydrologic regime has not been

sufficient to dissolve the caliche at the

site. If active dissolution of the

evaporites in the subsurface were

occurring in the WIPP area, it would be

expected that collapse features would be

evident in the Mescalero above the area

where the dissolution is, or has

occurred. As noted above, EPA has

found no evidence of direct

precipitation-related flow increases

typical of karst terrain, and no field

evidence of large channels or other karst

features. The relative pervasiveness of

the Mescalero Caliche over a long

period of time is also an indication that

there has been an arid climate and very

low recharge conditions over a long

period of time at the WIPP site. This,

combined with DOE’s near-future

precipitation assumptions, led EPA to

conclude that karst feature development

will neither be pervasive nor impact the

containment capabilities of the WIPP

during the 10,000 year regulatory

period. (Docket A–93–02, Item V–B–2,

CARD 14, Section 14.B.5; Item V–B–3,

Section 3.B.t)

The EPA concludes that dissolution

has occurred in the WIPP area outside

of the WIPP site, as evidenced by karst

features like Nash Draw. It is possible

that dissolution has occurred at the

WIPP site sometime in the distant past

(i.e., millions of years ago for stratabound features) associated with a

geologic setting other than that currently

present at WIPP; however dissolution in

the Culebra is not an ongoing process at

the WIPP site. Thus EPA finds that

DOE’s modeling (which assumes no

karst within the WIPP site boundary) is

consistent with existing borehole data

and other geologic information.

e. Presence of Brine in the Salado.

Numerous commenters stated the

Salado Formation will be wet and that

brine is weeping into the repository at

a slow but significant rate, leading to a

wet repository which will corrode the

waste containers. This, the commenters

stated, would invalidate the basic

premises of the WIPP that dry salt beds

would creep and encapsulate the waste

canisters.

The EPA agrees that brine will enter

the repository from the Salado

Formation via anhydrite marker beds.

The EPA also notes that the presence of

brine within the Salado is a key element

of the PA modeling; brine inflow is

assumed to occur and the impact of

brine inflow on gas generation is

assessed. Brine is necessary for both of

the processes that may cause gas

generation: either drum corrosion or

microbial respiration. If there is no

inflow of brine into the repository,

neither corrosion of iron drums nor

survival of microbes would occur, so gas

generation would not occur. Therefore,

although the commenters correctly

noted that initial WIPP studies did

assume the salt to be ‘‘dry,’’ the

presence of interstitial brine has long

been recognized and is accounted for in

the PA. (Docket A–93–02, Item V–B–2,

CARD 14, Section 14.E.5; Item V–B–3,

Section F.2)

In the CCA discussion of the gas

generation conceptual model, DOE

indicates that brine is expected to be

present in the repository due to a

natural inflow of brine. Corrosion of the

waste containers, generation of gases

resulting from waste corrosion and

microbial degradation, and the effects of

these processes on the disposal system

components have been addressed in the

DOE PA and the EPA-mandated PAVT.

(Docket A–93–02, Item V–B–2, CARD

14, Section 14.D; Item V–B–2, CARD 23,

Section 2.4; Item V–B–3, Section E.2)

The DOE also considered that additional

brine could be introduced to the waste

area if a drilling event passed through

the waste and subsequently hit a brine

pocket. The presence of a pressurized

brine pocket beneath WIPP was

addressed in the PA under the Human

Intrusion Scenarios whereby the

reservoir is penetrated by a borehole

and brine is subsequently released into

and mixed with the waste and

eventually discharged either into the

Culebra or at the ground surface. The

EPA concludes that DOE adequately

considered the presence of brine in PA

modeling because it included the

possibility of encountering a brine

pocket in its intrusion scenarios, and

because the potential effects of brine on

corrosion rates and gas generation were

incorporated in PA models. For more

information on brine pocket parameter

values, see the subsequent discussion of

Parameter Values in the Performance

Assessment sections of this preamble.

f. Gas Generation Model. Some

chemical reactions could occur in the

WIPP because metal containers holding

waste may corrode and waste made

from organic materials such as rubber

may decompose if water is available and

if other conditions are conducive to

such decomposition. The corrosion

reaction would create hydrogen gas

(H2). The decomposition of organic

waste would create carbon dioxide (2)

and methane (CH4). These gases would

build up in the repository after it is

sealed, increasing pressure inside the

waste rooms.

The DOE developed a gas generation

conceptual model to describe this

situation. The Department’s gas

generation conceptual model

incorporates the following basic

premises:

• Gas is generated primarily by metal

corrosion and microbial processes;

• Gas generation is closely linked to

other processes;

• Gas generation from microbial

processes will not always occur;

• High gas pressures in the repository

can cause the Salado anhydrite

interbeds to fracture; and

• High gas pressure is necessary

before spalling and direct brine releases

can begin.

The DOE performed experiments on

gas generation rates for the 1992 PA and

updated these experiments more

recently. (Telander, M.R. and R.E.

Westerman, 1997. ‘‘Hydrogen

Generation by Metal Corrosion in

Simulated Waste Isolation Pilot Plant

Environments,’’ SAND96–2538; see

Docket A–93–02, Item V–B–1.) The gas

generation rates are important in The

PA because build-up of high gas

pressures increases the chance for

releases if a drill bores into the

repository.

During the public comment period,

commenters questioned the gas

generation rates used in the gas

generation conceptual model. One

commenter stated that calculated

corrosion rates were too low because

they are based upon long-term tests that

show lower rates than short-term tests,

they assume a high pH, and they

include a minimum rate of zero,

perhaps by assuming that salt

crystallization will prevent corrosion.

The commenter also stated that

corrosion rates used in the model

should account for the fact that direct

contact with salt and backfill increases

the rate. The commenter further stated

that DOE seemed to use the observed

data to set the upper limit of a

distribution of corrosion rates, rather

than the midpoint of such a

distribution, which would

systematically understate the corrosion

rate because most values would be less

than the values taken from DOE’s

observed data. Finally, the commenter

stated that aluminum corrosion is as

significant as corrosion of steel, and that

it is likely to take place in the repository

because CO2 and iron will be present

and will enhance aluminum corrosion.

The EPA examined DOE’s studies on

gas generation rates. The EPA disagrees

that the assumptions of long-term rates,

pH, and minimum corrosion rate are not

well-founded. Since the results of the

corrosion testing are used to develop a

long-term hydrogen gas generation rate

for the repository that applies over
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27375

hundreds of years, it is appropriate that

DOE developed the rate based on

hydrogen generation over a longer time

(12 to 24 months) rather than for a

shorter time. Data indicate that during

the first few months of the test, the

corrosion reaction had not yet stabilized

at equilibrium, producing more

hydrogen gas than would have been

expected at equilibrium for the amount

of iron present. (Docket A–93–02, Item

II–G–1, CCA Reference #622) Therefore,

the higher rate of gas generation

observed in the short-term is unlikely to

represent what happens in the

repository over hundreds of years.

The DOE’s assumption of high pH

(about 10) is consistent with data on the

use of magnesium oxide (MgO) backfill.

Because DOE has committed to using

MgO backfill in the repository in the

CCA, EPA finds it reasonable to assume

this pH in the repository. (See the

preamble section ‘‘Engineered Barriers’’

for further discussion of MgO backfill.)

Furthermore, even if the MgO were not

fully effective and the pH were to drop

from near 10 to between 7 and 8, the

enhanced corrosion rate expected at that

lower pH is already reflected in the

probability distribution for the corrosion

rate parameter. DOE’s experimental data

show that MgO backfill will function as

assumed in the CCA. Therefore, EPA

concludes that DOE considered the

issue of pH and realistically

incorporated it into the model.

The DOE took its minimum corrosion

rate of zero from studies on steel

corrosion rates when the steel is in a

humid environment and also when steel

is submerged in brine. The DOE found

that virtually no corrosion occurred and

no hydrogen gas was generated under

humid conditions. Also, the studies

show that the steel has an extremely low

corrosion rate when it is submerged in

brine at the higher pH expected in the

WIPP. Some DOE studies also found

that salt films may prevent corrosion, as

the commenter mentioned. (Docket A–

93–02, Item II–G–1, CCA Appendix

MASS, Attachment MASS 8–2) Based

on all these studies, EPA concludes that

DOE’s minimum corrosion rate is

supported and appropriate.

The DOE assumed that the corrosion

rates of steel submerged in brine were

uniformly distributed from zero to 0.5

micrometers per year. The EPA believes

that the bases for the parameter

assumptions are adequately

documented and the use of the

particular parameter distribution is

consistent with demonstrating the

concept of reasonable expectation for

the H2 gas generation rates used in the

CCA. However, EPA was concerned that

the maximum corrosion rate value

selected by DOE did not fully reflect

other uncertainties. These uncertainties

included the accelerated corrosion of

steel in reactions with other materials

such as backfill and aluminum. Data

from DOE tests indicated that corrosion

rates might be twice as high as those

used in the PA. (Docket A–93–02, Item

V–B–14) Thus, in the PAVT, EPA

required DOE to double the maximum

corrosion rate to assure that these other

uncertainties were more fully reflected.

(Docket A–93–02, Item II–G–28)

(Doubling the corrosion rate would be

expected to cause the gas generation rate

to rise but not necessarily double, since

other factors such as microbial

degradation also influence gas

generation.) This and other changes

made in the PAVT showed that the

repository remained in compliance with

the standards.

The commenter correctly notes that

the corrosion data from DOE’s studies

were used to set the upper limit of a

uniform distribution of corrosion, rather

than a mid-point. (Telander, M.R. and

R.E. Westerman, 1997. See Docket A–

93–02, Item V–B–1.) However, EPA does

not agree that this practice would

systematically understate the corrosion

rate under the conditions expected to

occur in the repository. The

experimental rate was obtained under

pH conditions substantially lower than

those expected in the repository (i.e., 7.4

to 8.4 versus 9.2 to 9.9). The corrosion

rate is expected to be at least an order

of magnitude lower at the higher pH

than at the pH expected in the

repository in the presence of MgO.

(Docket A–93–02, Item V–B–14)

Therefore, the higher corrosion values

(i.e., those based on the study) represent

extreme conditions, rather than those

expected in the repository, and the

parameter range would account for all

values that are likely to occur. In

addition, as noted above, EPA required

that the maximum corrosion rate be

doubled in the PAVT to account for

uncertainties in this parameter. The

Agency believes that this addresses the

concerns raised by the commenter.

The commenter notes that CO2 and

iron will enhance the corrosion of

aluminum. Although EPA agrees this is

true, the Agency believes it does not

affect the results of the PA. Carbon

dioxide reacts with MgO, so CO2 will

not be available to reduce the brine pH

and to enhance corrosion. Second,

accelerated corrosion of aluminum is

not a significant factor in the WIPP’s

performance, since brine will be

consumed in corrosion reactions and

will lead to smaller direct brine releases.

(This is also discussed in the following

preamble section concerning two

dimensional modeling of brine and gas

flow.) The results of DOE’s modeling

show that iron is consistently left over

after reacting with all available brine.

(Docket A–93–02, Item II–G–7, Fig.

2.2.9) Based upon data on these

reactions, the Agency concludes that

enhanced corrosion of aluminum due to

CO2 and iron will not increase releases

of radioactivity because brine will not

be left over to go to the surface as direct

brine releases. (Docket A–93–02, Item

V–C–1)

g. Two-Dimensional Modeling of Brine

and Gas Flow. The DOE modeled the

flow of brine and gases within the

repository in the BRAGFLO computer

code. The DOE simplified this model by

representing the repository as a space in

two dimensions rather than in three

dimensions, as it is in reality. The

Department made this simplification in

order to speed up computer calculations

significantly. The DOE performed a

screening analysis titled S1: Verification

of 2D-Radial Flaring Using 3D Geometry

to see if the two-dimensional BRAGFLO

model would predict similar results to

a three-dimensional model. (WPO

#30840) In Appendix MASS,

Attachment 4–1 of the CCA, DOE

explained that the results of the

screening analysis showed that a threedimensional model would not give

significantly different results from the

two-dimensional model used in the PA.

The EPA examined DOE’s

documentation to determine if the CCA

complied with EPA’s requirements for

documentation of conceptual models

and consideration of alternative

conceptual models under §§ 194.23(a)(1)

and (a)(2). The EPA reviewed the

screening analysis and concluded in the

proposal that DOE sufficiently

documented its rationale and approach

behind using a two-dimensional model

for brine and gas flow in the repository.

(62 FR 58808)

One commenter stated that DOE’s

screening analysis suggested that the

two-dimensional (‘‘2D’’) BRAGFLO

model might underestimate releases of

radionuclides to the surface under

higher gas pressures. The commenter

stated that several three-dimensional

(‘‘3D’’) BRAGFLO simulations of the

repository should be performed using

parameter values from the CCA PA. The

recommended analysis would include

calculations of direct brine releases

(releases of brine contaminated with

radioactive waste) and spallings

(releases of solid waste pushed out of

the repository under high pressure), and

an assessment of how much brine

would be consumed by chemical

reactions. Another commenter stated

that the screening analysis had been
27376 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

22Lithostatic pressure is the pressure exerted by

overlying rock layers.

misinterpreted because details of the

assumptions used in the original

screening analysis had not been

considered. This commenter also stated

that results of additional analysis

submitted by DOE as comments showed

that the two-dimensional BRAGFLO

code used in the CCA PA results in a

conservative estimate of the releases

when compared to results from a threedimensional code.

The EPA examined the screening

analysis mentioned by the commenters.

The Agency found that the divergence

between the results of the twodimensional and three-dimensional

versions of BRAGFLO occurred only at

very high (lithostatic 22) pressures that

would occur seldom if ever in the

repository. (Docket A–93–02, Item V–C–

1, Section 5) For simulations at the gas

generation rates used in the CCA PA,

the two-dimensional BRAGFLO code

predicted greater brine inflows than the

three-dimensional code. (Greater brine

inflows could potentially lead to greater

direct brine releases.)

The EPA also considered how much

brine would be consumed in chemical

reactions. One of DOE’s studies showed

that brine is consumed by corroding

steel barrels and leaves behind at least

20 percent of the original steel at the

end of 10,000 years for 99 percent of the

sets of simulated conditions tested in

the CCA PA. (Docket A–93–02, Item II–

G–7, p. 2–12) Based on this study, EPA

concluded that even if the 3D model

predicted additional brine inflow

(beyond that predicted in the current 2D

model), this brine will simply be

consumed in chemical reactions (i.e.,

corrosion of metal drums), and will not

go to the surface as direct brine releases.

In addition, the Agency looked at results

of additional simulations that DOE

conducted to compare BRAGFLO 2D

and 3D results. (Docket A–93–02, Item

IV–G–34, Attachment 1 and February

25, 1998, memorandum) DOE’s results

show that the use of a two dimensional

representation does not result in an

underestimate of direct brine release

during human intrusion. In all cases

investigated, the two dimensional

simulations consistently predict either

the same or higher repository pressures

and brine saturations than their

corresponding three-dimensional

simulations, leading to larger releases.

The Agency, therefore, concludes that

the two-dimensional BRAGFLO code

results in conservative estimates of

releases from the repository compared

to results from a three-dimensional

model.

In addition, EPA found that DOE

sufficiently documented its

development of conceptual models and

scenarios, including alternative

conceptual models considered, in the

CCA and additional documentation

submitted to the Agency. Therefore,

EPA finds DOE in compliance with the

requirements of §§ 194.23(a)(1) and

(a)(2) with respect to modeling of brine

and gas flow.

h. Earthquakes. Several public

comments raised concerns about the

effect that earthquakes could have on

the repository and the containment of

waste. Several commenters refer to a

recent (January 4, 1998) earthquake in

New Mexico, over 100 miles from the

WIPP site, as an indication of the

weakness of the WIPP site for disposal

purposes.

In the CCA, DOE examined seismicity

as part of its features, events, and

processes, analyses, and concluded

earthquakes could be excluded from the

PA calculations based on low

consequences. This conclusion is drawn

from a wealth of knowledge about the

seismic activity and processes in the

region, but is based primarily on the fact

that the intensity of ground shaking (the

primary cause of destruction from an

earthquake) is significantly less

underground than at the surface. In

addition, the ductile nature of a salt

deposit makes it deform differently than

typical hard rocks, so the displacement

due to rupture (if any) will be less. The

EPA reviewed DOE’s earthquake

(seismic) scenario in the Technical

Support Document for 194.14: Content

of Compliance Application, Section

IV.B.4.f. (Docket A–93–02, Item V–B–3)

The EPA concurs with DOE’s analysis,

that the probability of a release of

radionuclides from the repository due to

the opening of fracture pathways caused

by an earthquake is very small.

Many years of seismological

monitoring, microseismal studies and

geologic study demonstrate that there

are no probable sources of large

earthquakes at or near the WIPP site.

(Docket A–93–02, Item II–G–1, Chapter

2.6) The only sources of significant

earthquakes in the region lie far to the

west of the site along the Rio Grande rift

or to the south along major plate

tectonic features in Mexico, although

measurable earthquakes have occurred

closer to the WIPP. (Docket A–93–02,

Item II–G–1, Chapter 2 and Appendix

SCR) Micro-earthquakes (magnitude 3.0

or smaller on the Richter scale), most of

which are too small to be felt, or small,

shallow teleseismal ground motion

related to distant earthquakes are the

only seismicity expected at the WIPP

site during the very short period that the

repository will persist as an

underground opening. The EPA notes

that the site of the January 4, 1998,

earthquake is located in the Rio Grande

Rift—over 100 miles east of WIPP—and

seismic activity in that area, including

the January 4, 1998 earthquake, was too

small to have an impact at WIPP.

Therefore, EPA finds that the effects of

earthquakes need not be considered in

performance assessments. (See Docket

A–93–02, Item V–B–2, CARD 32,

Section G)

i. Conclusion. The EPA finds that

DOE adequately assessed the site

characteristics for the purposes of the

PA and use in comparison with EPA’s

radioactive waste disposal standards

and WIPP compliance criteria. The

results of EPA’s review of the CCA and

additional information provided by DOE

is provided in CARDs 14, 23, 32 and 33.

(Docket A–93–02, Item V–B–2)

4. Parameter Values

a. Introduction. Parameters are

numerical values or ranges of numerical

values used in the PA to describe

different physical and chemical aspects

of the repository, the geology and

geometry of the area surrounding the

WIPP, and possible scenarios for human

intrusion. Some parameter values are

well-established physical constants,

such as the Universal Gas Constant or

atomic masses of radionuclides.

Parameters also can be physical,

chemical or geologic characteristics that

DOE established by experimentation.

The DOE has also assigned parameters

to aspects of human intrusion scenarios,

such as the diameter of a drill bit used

to drill a borehole that might penetrate

the repository.

Section 194.23(c)(4) requires detailed

descriptions of data collection

procedures, data reduction and analysis,

and code input parameter development.

Section 194.14(d) requires DOE to

describe the input parameters to the PA

and to discuss the basis for their

selection. Section 194.14(a) requires

DOE to describe the characteristics of

the WIPP site, including the natural and

engineered features that may affect the

performance of the disposal system,

which is part of the process of

parameter development.

The Agency reviewed the CCA,

parameter documentation, and record

packages for approximately 1,600

parameters used as input values to the

CCA PA calculations. The EPA further

reviewed parameters record packages

and documentation in detail for 465

parameters important to performance of

the disposal system. The Agency

selected parameters to review in depth

based on the following criteria:
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27377

23 Dissolved waste migrating out of the disposal

site would migrate as atoms with a positive

electrical charge, or cations; these could be cation

species such as Pu∂4 or U∂6. When liquid such as

brine carries the cations through sediment or rock,

some of the cations become attached to the surface

of these solids. Therefore, the cations travel more

slowly than the liquid as a whole. The rate of

advance of the cation as the liquid migrates can be

described with a number called a retardation factor.

Distribution coefficients, or Kd’s, are used in

calculating the retardation factor.

• Parameters that were likely to

contribute significantly to releases or

seemed to be poorly justified;

• Parameters that control various

functions of the CCA PA computer

codes that were likely to be important

to calculations of releases and important

to compliance with the containment

requirements of § 191.13; and

• Other parameters EPA used to

evaluate the overall quality of Sandia

National Laboratory’s (‘‘SNL’’)

documentation traceability.

After its initial review, EPA found

that DOE had a great deal of

documentation available in the SNL

Records Center supporting most of the

parameters used in the CCA PA.

However, EPA had some concerns about

the completeness of the list of CCA PA

parameters in the CCA and the SNL

Records Center, the description and

justification to support the development

of some code input parameters, and the

traceability of data reduction and

analysis of parameter-related records.

The Agency did not agree with the

technical justification of some

parameter values and probability

distributions.

The Agency later required DOE to

perform additional calculations in a

Performance Assessment Verification

Test (‘‘PAVT’’) in order to verify that the

cumulative impact of all required and

other corrections to input parameters,

conceptual models, and computer codes

used in the PA was not significant

enough to necessitate a new PA. The

EPA directed DOE to incorporate

modified values or distributions for

twenty-four parameters in the PAVT.

(Docket A–93–02, Item II–I–27) The

PAVT showed that the calculated

releases may increase by up to three

times from those in the original CCA

PA, but that the WIPP is still an order

of magnitude below the containment

requirements in § 191.13. The DOE

satisfied EPA’s concerns about the

parameters by incorporating EPA’s

changes to the parameter values and

parameter distributions in the PAVT.

During the public comment period on

the proposed rule, members of the

public expressed concern about a few

specific parameters used in the PAVT:

distribution coefficients (Kd), the

permeability of borehole plugs, the

characteristics of a potential brine

pocket, and the solubility of different

actinide ions in brine. Commenters

stated these particular parameters could

have an especially great impact on

releases, and therefore, on the results of

the PA.

b. Distribution Coefficient (Kd). As the

primary radionuclide pathway during

an intrusion, the Culebra was the

subject of many public comments,

especially related to distribution

coefficients 23 (Kd values). In DOE’s

conceptual model the Culebra is

characterized as a fractured dolomite

that has dual-porosity and acts to

physically retard movement of

contaminants. In a dual-porosity rock

unit, ground water is believed to flow

through the fractures, but water and

contaminants can access the pore space

within the rock matrix away from the

fractures. Movement of water and

contaminants into the pore space slows

(retards) their respective forward

movement. This physical retardation is

necessary in order to have chemical

retardation. In the process of chemical

retardation, contaminants diffuse from

the fractures into the pore space where

they can adsorb onto the rock mass.

This adsorption is described by

distribution coefficients, or Kd values.

The CCA indicated that there were no

contributions to total releases from the

ground water pathway. (Docket A–93–

02, Item II–G–1, Chapter 2) This was

due to the limited amount of

contaminated brine predicted to reach

the Culebra and the fact that

radionuclides adsorbed into the Culebra

dolomite did not move with the ground

water flow. That is, the movement of the

radionuclides were retarded with

respect to the ground water flow. The

estimate of the extent of the retardation

(i.e., the Kd value) was based on

laboratory tests using crushed rocks and

small columns of rock. (CCA, Docket A–

93–02, Item II–G–1, Chapter 6)

The EPA reviewed DOE’s Kd values in

detail. (Docket A–93–02, Item V–B–4)

Based upon the review of DOE’s data,

methodologies, and conclusions, EPA

proposed that the Kd ranges suggested

by DOE were sufficient for the PA. (62

FR 58799) The EPA also concluded that

the laboratory tests were conducted

appropriately and that the Kd values

DOE derived from this testing are

reasonable, given the experimental

evidence, and sufficient for PA

purposes. (Docket A–93–02, Item V–B–

2, CARD 14, Section 14.B.5)

Commenters stated that DOE’s

experiments did not produce Kd values

that are representative of conditions in

the Culebra. The DOE data on actinide

Kd values are derived directly from the

results of a number of experiments (e.g.,

crushed rock, column tests) conducted

with brine solutions that are

representative of brines in the disposal

system. The DOE used samples of the

Culebra Dolomite and brine solutions

that are considered to be representative

of the field situation. These data were

supplemented by experiments with

other natural dolomites and column

experiments, in which the effects of a

field-realistic solid to solution ratio

could be investigated. The laboratoryderived Kd values are expected to

overestimate the mobilities of the

actinides, making them reflective of

upper bounds for predicting the

maximum possible rates of actinide

migration in the PA calculations.

Therefore, it is reasonable to expect that

the range of actinide Kd values obtained

from the DOE experiments are inclusive

of any scale-effects that might produce

a different average Kd value than the

experimental average in either the

greater or lesser directions. Docket A–

93–02, Item V–B–4, Section 4.4 presents

EPA’s analysis of field Kd testing.

The DOE’s experimental results show

that each of the actinides tested is

adsorbed to the rock matrix to varying

extents; hence, they will not migrate as

fast as the overall rate of horizontal

water flow (i.e., the actinides will be

attenuated). These results are consistent

with general theories of the adsorptive

behavior of cationic solutes under

alkaline pH conditions.

The EPA reviewed DOE’s actinide Kd

values and concluded that the

population of Kd values determined in

DOE experiments was not wellrepresented by a uniform distribution.

The Agency recommended that a

loguniform distribution be used in the

PA calculations. In the PAVT,

loguniform distributions for the actinide

Kd values were used. (WPO# 47258;

Docket No A–93–02, Item II–G–39) The

results of PAVT still resulted in

compliance with regulatory release

limits. Therefore, EPA determined that

the CCA PA was adequate for the

purpose of determining compliance.

(Docket A–93–02, Item V–B–4)

The DOE also performed bounding

calculations using the minimum Kd

values necessary to achieve compliance

with EPA limits. The bounding

estimates were obtained for plutonium

(239Pu) and americium (241Am), which

are critical actinides with respect to

releases to the accessible environment.

Results of DOE’s bounding assumptions

(whereby all other factors are set to the

least favorable value) indicate that a Kd

of 3 milliliter per gram (ml/g) is

sufficient for compliance for 239Pu and
27378 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

241Am. Estimates based on typical CCA

sample sets indicate that Kd values

greater than 1 ml/g are sufficient for

compliance. (A higher Kd value

indicates greater retardation—or less

movement—of radionuclides.) The Kd

ranges determined from DOE column

experiments, conducted since

submission of the CCA, for 239Pu and

241Am are typically greater than 100 ml/

g, thus inferring that Kd values used in

the PA are more than sufficient to

ensure compliance with EPA limits with

respect to accessible environment

release through the Culebra. For these

reasons, the actinide Kd values

developed by DOE are considered to be

adequate for representing actinide

mobilities in the PA calculations.

(Docket A–93–02, Item V–B–2, CARD

14, Section 14.G.5)

The EPA reviewed and responded to

the public comments on Kd values and

finds the Kd values used in the PA are

sufficient. Refer to EPA Technical

Support Document for Section 194.14:

Assessment of Kd Values Used in the

CCA for EPA’s detailed review. (Docket

A–93–02, Item V–B–4)

c. Actinide Solubility. Actinide

solubilities are used in the computer

codes to calculate the actinide

concentrations released from the

repository. They are important because

as radionuclides dissolve in brine, they

are more easily released from the

disposal system through direct brine

release mechanisms. Commenters

questioned the analysis of certain

chemical conditions in the disposal

system relating to backfill, ligands,

uncertainty, and oxidation state

analogy.

An important factor influencing

actinide solubility is the magnesium

oxide (MgO) backfill DOE proposed to

emplace in the WIPP. The DOE

indicated that MgO backfill emplaced

with transuranic waste would mitigate

the solubility-enhancing effects of

carbon dioxide from waste degradation.

The DOE proposed to emplace a large

amount of MgO in and around waste

drums in order to provide an additional

factor of safety and thus account for

uncertainties in the geochemical

conditions that would affect CO2

generation and MgO reactions.

Commenters stated that DOE has not

shown the predicted MgO chemical

processes will take place. The DOE

provided documentation in the CCA

and supplementary information that

MgO can effectively reduce actinide

solubility in the disposal system. While

the conceptual model peer review panel

initially rejected DOE’s

conceptualization of the Chemical

Conditions Model, DOE provided

additional information on MgO

processes and the peer review panel

later concluded that MgO processes will

indeed take place as initially postulated

by DOE. The EPA concluded that DOE’s

qualitative justification was sufficient to

show that the emplacement of MgO

backfill in the repository will help

prevent or substantially delay the

movement of radionuclides toward the

accessible environment by helping to

maintain alkaline conditions in the

repository, which in turn favors lower

actinide solubilities. Furthermore,

DOE’s bounding of pH levels to a

narrow range greatly reduces the

uncertainty associated with pH and

actinide solubility in the PA. Refer to

CARD 24, Section 24.B.6, and CARD 44

for further discussion of the effects of

MgO. (Docket A–93–02, Item V–B–2)

The EPA received numerous

comments regarding DOE’s lack of a

sensitivity analysis on the effects of

organic ligands and that organic ligands

other than ethylene diaminetetraacetic

acid (‘‘EDTA’’) should have been

considered. Organic ligands are

important since they can increase more

mobile fractions, i.e., can make more

radionuclides available for transport.

Organic chemicals are expected to be

part of the waste, especially because

many were used in the separation of

actinides during chemical processing of

nuclear materials. DOE’s bounding

calculations and incorporation of

uncertainty ranges to represent actinide

concentrations in the PA calculations

indicate that organic ligands will have

only a minor effect on the solubilities of

actinide solids under the expected

repository conditions. The EPA found,

through independent calculations, that

there is no substantive information that

could be gained by conducting a

sensitivity analysis on the effects of

organic ligands or conducting the

calculations with citrate rather than

EDTA, since EDTA provides a

conservative assessment of the effects of

ligands on solubility of actinide solids.

(Docket A–93–02, Item V–B–2, CARD

24, Section 24.E.5) The EPA agrees with

the conclusions of the Waste

Characterization Independent Review

Panel ‘‘that under the conditions of

MgO backfill, chelating agents (e.g.,

organic ligands) will have a negligible

effect on repository performance. The

Panel notes that, even at the basic pH in

the repository, the availability of

transition metals may be enhanced due

to the formation of soluble halo

complexes, making an even stronger

case that base metals control ligand

chemistry.’’

Commenters also expressed concern

about the solubility uncertainty range

used in the PA computer codes. The

DOE determined that the available

experimental data for the oxidation state

+IV actinides (i.e., plutonium, uranium,

and neptunium) were insufficient for

making such comparisons. However, the

experimental procedures for

determining the solubilities of +IV

actinide solids are not substantially

different from those used to determine

the solubilities of +III and +V actinide

solids. Therefore, EPA concluded that

the uncertainties determined for the +III

and +V actinide solids would be

inclusive of those that would be

obtained for +IV actinide solids, which

are based on experimental

measurements of thorium oxide. This

expectation is based on the fact that

DOE used the outermost limits of the

differences between model results and

experimental results for all data

examined to define the breadth of the

uncertainty limits. This procedure

greatly expands the size of the

uncertainty bounds beyond what might

be calculated from statistical treatment

of the distribution of the differences.

(Docket A–93–02, Item V–B–2, CARD

24, Section 24.B.6; and Item V–B–17)

The EPA therefore finds that the

uncertainty bounds on actinide

solubility are adequate for use in the

PA.

Finally, commenters raised issues

regarding the limitations of the

oxidation state analogy in the Actinide

Source Term Dissolved Species Model.

In short, the actinide oxidation analogy

means that actinides of the same

oxidation state tend to have similar

chemical properties under similar

conditions. The oxidation state analogy

is based on standard inorganic

chemistry principles. This

generalization can be made because

chemical reactions involving ionic

species are related primarily to the

charge densities of the reacting species.

Actinides with the same oxidation state

have the same core electronic structure;

hence they have similar ionic radii and

charge densities, which in turn leads to

analogous chemical behavior in

solubility and aqueous speciation

reactions. In addition to the theoretical

basis, DOE conducted experimental

studies that confirmed the validity of

the oxidation state analogy, and

subsequently employed it in its

representation of the solubilities of

actinides. The EPA finds that the

actinide oxidation state is adequate for

use in the PA. (Docket A–93–02, Item

V–B–2, CARD 24, Section 2.B.6)

For details regarding chemical

reactions of MgO, see CARD 24 (Waste

Characterization) and CARD 44

(Engineered Barriers). For further
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27379

information regarding the PA modeling

of solubility and chemical conditions in

the repository, see CARD 23 (Models

and Computer Codes). CARDs can be

found in Docket A–93–02, Item V–B–2.

d. Brine Pockets. The Castile

Formation lies underneath the Salado

Formation, where the WIPP is located.

This stratum contains pockets of brine

under pressure. One of the parameters

in the PA that commenters believed to

be important is the probability that a

driller will hit a brine pocket in the

Castile. The CCA PA models the

possibility that a drill bit could

penetrate a brine pocket in the Castile

Formation, allowing brine to rise up the

borehole and into the repository. The

brine could then dissolve radioactive

waste and could carry it to the earth’s

surface if another driller bored a hole

into the repository. This could increase

the amount of radioactive waste

reaching the accessible environment.

Some commenters expressed concern

that brine from brine pockets in the

Castile Formation could travel up to the

level of the repository, or even to the

earth’s surface. The EPA believes that

this is not a problem unless the

repository is disturbed by human

intrusion. Because it is difficult for

water to travel in the Salado and Castile

formations (i.e., they have low

permeability), there is no natural

connection between a Castile brine

pocket and the waste panel area under

undisturbed conditions. These brines

are also either saturated or nearly

saturated with soluble minerals such as

salt (halite), and thus, the brine in

pockets will not dissolve the

surrounding material. (Docket A–93–02,

Item II–G–1, CCA Chapter 2, Table 2–5)

However, in the case of a deep drilling

intrusion that goes through a waste

panel and into the Castile, it is possible

that the driller will intercept brine in

the Castile and create a pathway for

Castile brine to flow into the repository

and interact with the waste. The

probability of human intrusion through

the WIPP repository to an underlying

Castile brine pocket is a key component

of the PA.

The 1992 draft PA considered the

probability of a driller hitting a brine

pocket under the waste area with a

range of 25 percent to 62 percent, based

on geophysical work that suggested

brine may be present. (Docket A–93–02,

Item II–G–1, Reference #563) In the CCA

PA, DOE assigned a probability of

hitting a brine pocket of 8 percent,

based upon a geostatistical analysis of

oil and gas wells in the vicinity of

WIPP. The Agency believed that the

assigned probability was low, based

upon data from one particular DOE

study using the Time Domain

Electromagnetic (‘‘TDEM’’) method. In

addition, EPA found there was

considerable uncertainty in this

parameter. Therefore, in the PAVT the

Agency required DOE to change the

constant value of this parameter to a

uniform probability distribution from 1

percent to 60 percent, based upon data

in the TDEM study. (Docket A–93–02,

Item II–I–27)

Many commenters questioned the use

of a uniform distribution from 1 percent

to 60 percent as the range for the

probability of hitting a brine pocket that

EPA specified be used in the PAVT.

Some believed that EPA should require

DOE to examine a probability of 100

percent for hitting a brine pocket, based

upon data from DOE’s WIPP–12

borehole, which suggested that a large

reservoir of brine might lie in the Castile

Formation under the WIPP Land

Withdrawal Area. Others recommended

that EPA require DOE to repeat the PA

assuming a constant probability of 60

percent.

The EPA carefully evaluated the

potential occurrence of brine pockets

below the WIPP. The EPA agrees that

there is significant uncertainty

concerning the existence of a brine

pocket beneath the repository. For this

reason, EPA required DOE to reevaluate

the probability of hitting a brine pocket

in the PAVT using a probability

distribution rather than a constant

value.

The EPA also considered the

possibility that the brine pocket

indicated by WIPP–12 data may

underlie 100 percent of the repository.

Based on reservoir volume and

thickness data from WIPP–12,

commenters found that a cylindricallyshaped reservoir could underlie the

entire repository. However, EPA

considers this unlikely because brine in

the Castile does not reside in

homogeneous and well-defined

reservoirs. Instead, it is believed to

reside in vertical or subvertical fracture

systems, which may be extensive and

contain significant volumes of brine.

(Docket A–93–02, Item II–G–1,

Appendix MASS, Attachment 18–6)

Although EPA agrees that part of the

WIPP–12 reservoir may underlie part of

the repository, the time-domain

electromagnetic (‘‘TDEM’’) survey data

do not support speculation of a 100%

probability of an encounter. (Docket A–

93–02, Item II–G–1, Chapter 2.2.1.2.2,

Item V–B–3, section IV; Item V–B–14,

Sections 4.1, 4.4, and 4.5) In addition,

as pointed out by one of the commenters

recommending a probability of 60

percent, some boreholes adjacent to

brine-producing boreholes near the

WIPP site are known to be dry. In view

of the lack of support from the TDEM

data and the other concerns expressed

above, EPA concludes that available

data do not support a 100 percent

probability of hitting a brine pocket.

The EPA established its 1 percent to

60 percent range of probability for

hitting a brine pocket based upon data

from the TDEM survey. The Agency

examined the data and found that the

probability distributions for

encountering brine under the WIPP

varied widely, depending on whether or

not one assumed that brine pockets exist

below the bottom of the Anhydrite III

layer near the top of the Castile

Formation. Using the base of the

anhydrite layer as the cutoff, EPA’s

simulations showed that the fraction of

the excavated area of the repository

underlain by brine varies from 1 to 6

percent of the excavated area. Using the

base of the Castile as the cutoff, the

fraction of the excavated area of the

repository underlain by brine would

range from about 35 to 58 percent.

According to the 1992 WIPP PA, Castile

Formation brines are generally found in

the uppermost anhydrite layer (usually

Anhydrite III), rather than all the way

through the Castile. (Docket A–92–03,

Item II–G–1, CCA Reference #563, Vol.

3, p. 5–4) If brine is confined to the

upper (Anhydrite III) layer, which is the

more probable case based on geologic

information, the maximum fraction of

the repository area underlain by brine is

6 percent. However, in order to examine

the possible effects of the more

conservative case, EPA chose to assume

an equal probability that a driller would

hit a brine pocket in either the upper

Anhydrite III layer or the base of the

Castile. Therefore, EPA used a

probability range in the PAVT with a

low value of 1 percent based on the

upper anhydrite layer and the high

value of 60 percent derived by rounding

up the highest value from the TDEM

survey. The EPA believes that existing

information supports the range used in

the PAVT as valid, and probably

conservative, values for the probability

of hitting a brine pocket.

The Agency also notes that a

sensitivity analysis of the PA parameters

submitted in comments showed that the

final results of the PA were not

significantly affected by increasing the

probability of hitting a brine pocket.

Even when the Castile brine encounter

probability was increased to 100

percent’the highest possible

probability’there was no significant

difference between the resulting mean

CCDF and the mean CCDF in the CCA,

which was based upon a brine

encounter probability of 8 percent.
27380 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

(Docket A–93–02, Item IV–G–43) The

EPA believes that 100 percent is an

unrealistically high probability. The

results of this study confirm that

examining such a probability in more

detail would provide little added

information about the performance of

the WIPP.

Commenters stated that the range of

the compressibility of rock surrounding

a Castile brine pocket used in the CCA

PA was too wide. They also believed

that the brine pocket volume values

used in the PA were too small. Castile

rock compressibility is one of several

parameters that affects the volume of

brine pockets in the Castile. This is

important because a drill bit would be

more likely to hit a large brine pocket

than a small one.

The EPA agrees with commenters that

DOE’s parameters for rock

compressibility in the Castile and

representation of brine pocket size/

volume in the CCA PA were not

consistent with available information.

The EPA also believes that the

parameters of the Castile brine pockets

are highly uncertain. In order to capture

this uncertainty, the Agency believed it

would be appropriate to sample from a

range of parameter values, rather than to

use a single estimate, as DOE did in the

CCA PA. In the PAVT, EPA required

DOE to use a range of possible brine

pocket volumes. (WPO#41887. See

Docket A–93–02, Item V–B–1. See also

Docket A–93–02, Item V–B–14.)

Changing the rock compressibility of the

Castile and the Castile porosity

effectively modified the sampled brine

pocket volume to include, more

representatively, the possibility of larger

brine pocket volumes like those

expected based on data from the WIPP–

12 borehole. The EPA found that

modification of these parameters in the

PAVT did not result in releases that

exceed EPA’s containment standards.

Based on these results, EPA has

concluded that the CCA PA was

adequate for the purpose of

demonstrating compliance.

e. Permeability of Borehole Plugs. In

the PA modeling, DOE assumed that

people drilling for resources would

follow standard practice and plug the

boreholes left behind. As long as these

borehole plugs remain intact, the

pressure of gases generated from the

waste will build up inside the

repository. The more permeable the

borehole plugs are, the more gas will be

capable of escaping from the repository.

This would reduce pressure in the

repository and therefore would reduce

the potential for releases of radioactivity

through spallings or direct brine release

from a future drilling event. In the CCA

PA, DOE modeled a situation in which

borehole plugs between the Castile and

Bell Canyon Formations would remain

impermeable, and most borehole plugs

closer to the earth’s surface would

disintegrate after two hundred years and

would become more permeable.

One commenter stated that the CCA

does not model the gas buildup which

would result from impermeable plugs.

The EPA does not agree that the CCA

does not model gas buildup. In the CCA

PA and PAVT, gas pressure is allowed

to build up in the undisturbed

repository. Pressure would be released if

a borehole is drilled into the repository.

In some of the PA simulations, pressure

builds up again, although not to

undisturbed levels, after it is released

during a borehole intrusion. (Docket A–

93–02, Item II–G–7, Figure 3.3.1)

However, EPA was concerned about

DOE’s assumption that a relatively small

number of borehole plugs would have

low permeability. In the CCA PA, DOE

assumed that 98 percent of the

boreholes would be plugged with either

two or three plugs, where the top plug

would degrade and become more

permeable, and 2 percent of the

boreholes were plugged with a single

low permeability plug. The EPA was

concerned that an assumption that only

2 percent of the boreholes had low

permeability might not be conservative.

Therefore, EPA required that the

permeability range for borehole plugs in

the PAVT be broadened to include

lower values (at which gas will not

escape at a significant rate). This

parameter change ensured that the

PAVT would more frequently

incorporate low borehole permeability

and gas pressure buildup for more

simulations than in the CCA PA,

providing a more conservative result.

Other commenters expressed concern

that the borehole plug permeabilities

used in the CCA PA and the PAVT were

too high, and might underestimate

releases of radioactive material from the

WIPP. One commenter pointed out that

EPA retained the permeability used by

DOE as a high value and then added a

range of permeabilities extending to

lower values after the Agency rejected

DOE’s initial value as too high.

In the PAVT, EPA required that two

changes be made regarding the

permeability of the borehole plugs.

First, the Agency required that the

permeability of the intact plugs during

the first two hundred years of the plug

lifetime be treated as a variable or

probability distribution rather than as a

fixed parameter, with a range bounded

by values found in the literature. The

range of values included borehole plug

permeabilities both higher and lower

than the constant permeability used in

the CCA. In addition, EPA required DOE

to use a range of permeability values to

represent the permeability of borehole

plugs that have started to degrade. The

upper end of the new range was the

same permeability as that used in the

CCA, but the lower end of the range was

reduced by three orders of magnitude

and the median was reduced by an

order of magnitude. The Agency

believed that the upper end of the range

chosen by DOE, based upon the

permeability of silty sand, was

reasonable because an abandoned

borehole plug could degrade to this type

of debris over long periods of time.

Since the permeability of the actual

borehole fill material at some time well

into the future is unknowable, the

Agency believes that the use of data

based on natural materials is a

reasonable approach. However, the

Agency was not satisfied with the

rationale for the lower end of the range

originally chosen by DOE. The EPA

believes that there is some probability

that the concrete borehole plugs will not

degrade as assumed in the CCA PA.

Consequently, in the PAVT, EPA set the

lower end of the range at a permeability

value consistent with intact concrete.

One commenter stated that DOE had

not sufficiently accounted for

uncertainty in the lifetime of a borehole

plug before it degrades. (A borehole

plug with a longer lifetime would take

longer to become more permeable and

would allow more gas to build up in the

repository.) This commenter stated that

DOE should perform additional

calculations to investigate how borehole

plug lifetimes could influence

repository conditions and compliance

with the containment requirements.

The EPA also initially had concerns

that uncertainty about the lifetime of

borehole plugs had not been sufficiently

represented in the CCA PA. In order to

reflect this uncertainty, the Agency

required DOE to use a probability

distribution of borehole plug

permeabilities for intact plugs during

the first two hundred years of their

lifetime in the PAVT, rather than a

constant value. The sampled range of

permeabilities includes values

representing the permeability of both

intact (newer) plugs and disintegrating

(older) plugs. Therefore, EPA believes

that this change made in the PAVT

adequately addresses the effects of

uncertainty in borehole plug life.

5. Other Performance Assessment Issues

The EPA used many methods to

analyze specific scenarios or

characteristics that DOE included in the

PA. Commenters had concerns about
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27381

24BRAGFLO predicts gas generation rates, brine

and gas flow, and fracturing within the anhydrite

marker beds in order to predict the future state of

the repository.

25BRAGFLO—DBR calculates the amount of

waste that dissolves in brine and travels in the

contaminated brine as a direct brine release.

26CUTTINGS—S predicts the volume of solid

waste released from the repository because of

human intrusion drilling. This includes releases

from cavings (material that falls from the walls as

a drill bit drills through), cuttings (material that is

actually cut by a drill bit during drilling, including

any waste), and spallings (releases of solids pushed

up and out by gas pressure in the repository).

27SOURCE TERM calculates actinide solubilities

within the repository. The solubility values are then

used in the NUTS and PANEL codes to calculate

the actinide concentrations in brine released from

the repository.

28CCDFGF calculates the complementary,

cumulative distribution functions (‘‘CCDFs’’) used

to show compliance with EPA’s containment

requirements.

these methods, since the soundness of

EPA’s conclusions would depend upon

the soundness of the methods used to

reach those conclusions. Commenters

disagreed with aspects of a few types of

analyses in particular: sensitivity

analysis, and the PA verification test

(‘‘PAVT’’). Sensitivity analysis is a

computer modeling technique that

examines whether results of computer

modeling will change significantly if a

particular parameter value is changed.

The EPA’s approach to sensitivity

analysis is documented in EPA’s

Technical Support Document for

Section 194.23: Sensitivity Analysis.

(Docket A–93–02, V–B–13) The PAVT

was a set of 300 simulations of

additional performance assessment

calculations required by EPA. The

PAVT implemented DOE’s PA modeling

using the same sampling methods as the

CCA PA, but incorporating parameter

values that were selected by EPA.

Because some commenters disagreed

with DOE’s approach to the PA and

EPA’s approach to its analysis, they

recommended that the Agency require

DOE to repeat the PA using different

scenarios or characteristics of the WIPP

and its surroundings; these issues are

discussed in preceding sections of this

preamble related to the PA.

a. Sensitivity Analysis. Computer

modelers perform a sensitivity analysis

for a parameter in a model to find out

if results of modeling are sensitive to

(significantly affected by) that

parameter. If the results of modeling are

not sensitive to the parameter, then the

exact value of the parameter is not

important to the results of modeling.

The compliance criteria require DOE

to document the development of input

parameters for the PA under

§§ 194.14(d), 194.23(c)(4), and

194.34(b). As part of its parameter

development, DOE conducted a

sensitivity analysis of parameters used

in the CCA PA. (Docket A–93–02, Item

II–G–1, Appendix SA, Volume XVI) The

EPA reviewed this and supplementary

information that documents DOE

sensitivity analysis of the parameters

sampled in the PA. (Docket A–93–02,

Item II–G–7) As the Agency continued

in its review of the CCA and supporting

documentation, EPA found that there

were three categories of parameters not

fully documented in the CCA

documents or in the Sandia National

Laboratory WIPP Records Center. These

categories were: (1) parameters lacking

supporting evidence; (2) parameters

having data records that support values

other than those selected by DOE; and

(3) parameters that are not explicitly

supported by the relevant data or

information. The EPA expressed

concern about 58 parameters of the 465

parameters that EPA reviewed in detail.

(Docket A–93–02, Item II–I–17) For

these 58 parameters, EPA evaluated

whether changing the parameter values

would have a significant impact on the

results of computer modeling, primarily

through the use of a sensitivity analysis.

(Docket A–93–02, Item V–B–13)

(Distribution coefficients, or Kd values,

were examined in separate calculations

and analyses conducted by EPA.

(Docket A–93–02, Items V–B–4, V–B–7,

and V–B–8)) In its sensitivity analysis,

the Agency examined changes in output

from the PA models’ major submodels

that calculate releases and solubility of

actinides: BRAGFLO 24, BRAGFLO—

DBR25, CUTTINGS—S 26, SOURCE

TERM 27, and CCDFGF 28. The EPA

found that 27 of the 58 parameters have

a significant impact on the results of

modeling and that 31 of the 58

parameters did not have a significant

impact. Some of these parameters (both

significant and insignificant to results)

were subsequently determined to be

adequately supported based on

additional documentation provided by

DOE or Sandia National Laboratory.

(Docket A–93–02, Items II–I–25 and II–

I–27) For parameters that might have an

impact on the results of the PA and

were found not to be adequately

supported, EPA required DOE to

perform a Performance Assessment

Verification Test with revisions to the

significant parameters.

Commenters stated that they had

concerns about the submodel approach

used in EPA’s sensitivity analysis. One

commenter stated that EPA had not

justified this approach, beyond stating

that it was ‘‘a more sensitive method’’

than examining the final results of the

complete PA model. Another

commenter stated that EPA had not

shown that the submodel approach for

testing sensitivity related in any

particular way to the compliance

demonstration with the containment

requirements. This commenter also

stated that EPA had not explained or

justified why the analysis used the

average of changes in the outputs of the

submodels, and that averaging output

changes might disguise the significance

of a parameter value change if some

outputs change in direct response and

others change inversely.

The DOE’s PA model uses almost

1600 parameters. Even an important

parameter may change the final results

of the PA by a relatively small

percentage because so many parameters

contribute to the final results. The

different submodels contain far fewer

parameters than the complete PA.

Therefore, a change in any one

parameter will cause a greater

percentage change in the output from a

submodel than in the final result of the

entire PA modeling. It is for this reason

that EPA chose to use submodels. This

approach provided intermediate results

that would be a more sensitive measure

of reactions of a model to changes in

input parameters than the resultant

complementary cumulative distribution

functions (‘‘CCDFs’’) used to determine

compliance.

The submodel outputs that EPA

analyzed for sensitivity included the

outputs most closely linked with

radionuclide release and the ability of

the WIPP to meet EPA’s containment

requirements. Examples of submodel

outputs are gas pressure in the

repository; cumulative brine release into

the Culebra dolomite; cumulative

cavings release and cumulative

spallings release to the earth’s surface;

and brine flow into the anhydrite

interbeds away from the repository. If a

parameter changes the submodel

outputs significantly, it may have a

significant impact on the final results of

the PA; however, if a parameter does not

change the submodel output

significantly, then it cannot change the

final results of the PA significantly. In

addition, EPA notes that the nature of

the testing—which included three

model runs at low, average, and high

parameter values—means that it is not

practical to develop mean CCDFs. It

would be necessary to run all of the PA

codes for each parameter change a

hundred times to create a single CCDF.

Therefore, except for those parameters

included in the CCDFGF code, it would

have been extremely cumbersome and

time-consuming to perform a sensitivity

analysis on the final results of the PA.

The Agency disagrees that averaging

the submodel outputs disguises the

significance of a parameter value change
27382 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

29Absolute value is the magnitude of a number,

without a positive or negative sign. For example,

positive three and negative three both have an

absolute value of three.

if some outputs change in direct

response and others change inversely.

The EPA used absolute values 29 of the

percent changes in computing the

average percent changes. If two

parameters had inverse relationships,

those relationships would not cancel

each other out because the final results

would be an average of the absolute

values. Averaging of the percent

changes in the key submodel outputs

was a significant step only for the

parameters in the BRAGFLO code,

where average changes to output were

developed based on 11 model outputs.

The EPA averaged the results of these

eleven outputs in order to give equal

weight to each in determining the

sensitivity of BRAGFLO parameters.

Several members of the public

commented that most of the sensitivity

analyses varied only one parameter,

rather than varying several parameters

at a time, which potentially could show

a significant combined result. The EPA

varied single parameters in most of the

analyses to identify those parameters

that were most important to the PA

results. One of the problems with

varying multiple parameters

simultaneously is that it is difficult to

determine which parameter (or

parameters) led to the observed result.

Analysis of groups of parameters

requires the Agency to find that the

entire group of parameters is sensitive

or not sensitive. In addition, if some

parameters in a group increase releases

while others reduce releases, a group

analysis may not detect actual

sensitivity for individual parameters.

This is because the sensitivity analysis

typically looks at low, high, and average

values for all parameters in the group

simultaneously. Without examining the

sensitivity of individual parameters, the

analyst would not always know enough

about the parameters to be able to

predict the most extreme situation with

the greatest consequences of releases.

The ability to determine the significance

of individual parameters is important

because this allows one to improve the

model’s predictive capability by

focusing resources on those parameters

that are most sensitive and have the

greatest impact on results. It is true that

EPA did not perform a separate

sensitivity analysis run on groups of

parameters that it determined were

insensitive through individual

parameter tests. The Agency believes

that this is not necessary because the

cumulative calculated sensitivity of

these insensitive parameters is so small

compared to the sensitive parameters.

For example, the sum of the percent

changes for all 33 insensitive parameters

in BRAGFLO together was 47 percent

(ranging from 0 percent to 10 percent

each), while the percent change for the

individual sensitive parameters ranged

from 101 percent to 103,611 percent

each. (Docket A–93–02, Item V–B–13,

Table 3.1–1) Therefore, EPA concluded

that those parameters it found

insensitive through analysis of

individual parameters will not have a

significant effect on results of the PA

and do not need to be re-analyzed in

groups.

In addition to performing its own

sensitivity analysis on parameters, the

Agency required DOE to complete a

comprehensive recalculation of the

entire PA in the Performance

Assessment Verification Test (‘‘PAVT’’).

The purpose of the PAVT was to

perform a complete evaluation of the

synergistic effects of changing important

and questionable parameters on the

outcome of the PA calculations. The

results of the PAVT indicate that the

calculated releases would increase

when changes are made to the sensitive

parameters identified by the Agency,

but the revised results of the PA with

these more conservative parameter

values would still be an order of

magnitude less than the containment

requirements of 40 CFR 191.13.

A commenter stated that EPA’s

sensitivity analysis did not vary

conceptual models. The Agency agrees

that this is true. The objective of EPA’s

sensitivity analysis was to determine the

importance of selected individual

parameters and groups of parameters to

the PA results. The purpose of a

sensitivity analysis on conceptual

models would be to determine if model

results would change significantly using

different assumptions or using

alternative conceptual models. The EPA

examined the conceptual models and

alternatives, under §§ 194.23(a)(1) and

(a)(2). As a result of this review, EPA

required DOE to conduct a sensitivity

analysis on Culebra transmissivity and

to examine the assumption that the

Culebra acts as a fully confined system

as it pertains to hydrogeochemistry of

the Culebra. (Docket A–93–02, Item II–

I–17) The EPA found that the sensitivity

analysis results supported DOE’s

treatment of Culebra transmissivity and

treatment of the Culebra as a confined

system because of the minimal impact

on results when changing assumptions.

(Docket A–93–02, Item II–I–31) In

addition, the Conceptual Models Peer

Review Panel reviewed the conceptual

models, as required by §§ 194.27 and

194.23(a)(3)(v). The Agency finds that it

is not necessary to perform further

sensitivity analysis on conceptual

models because both the Agency’s and

the Panel’s reviews accomplished the

purpose of evaluating the impact of

using different assumptions or using

alternative conceptual models. These

reviews found all the conceptual models

except the spallings model to be

adequate for use in the PA, and

concluded that the spallings values used

in the CCA PA are reasonable for use in

the PA. (Docket A–93–02, Item V–B–2,

CARD 23, Section 7)

The EPA determined that DOE

adequately provided a detailed listing of

the code input parameters; listed

sampled input parameters; provided a

description of parameters and the codes

in which they are used; discussed

parameters important to releases;

described data collection procedures,

sources of data, data reduction and

analysis; and described code input

parameter development, including an

explanation of quality assurance

activities. The DOE also documented

the probability distribution of these

parameters, as required by § 194.34(b).

The Agency analyzed parameter values

used in the CCA, including DOE’s

documentation of the values and EPA’s

sensitivity analysis. The EPA also

required DOE to change these parameter

values in the PAVT and found that the

WIPP is still an order of magnitude

below the containment requirements in

§ 191.13. (For further discussion of

values for several specific parameters,

refer to the preceding preamble

discussion, ‘‘Parameter values.’’ See also

Docket A–93–02, Item V–B–2, CARD 23,

Sections 8 and 9.) Therefore, the Agency

determines that the CCA complies with

§§ 194.14(d), 194.23(c)(4) and 194.34(b).

b. Performance Assessment

Verification Test. The containment

requirements at § 191.13 indicate that a

disposal system is to be tested through

a PA that predicts the likelihood of

occurrence of all significant processes

and events that may disturb the disposal

system and affect its performance, and

that predicts the ability of the disposal

system to contain radionuclides. Section

191.13 requires that a disposal system

be designed so that there is reasonable

expectation that cumulative releases (1)

have a probability of less than one in ten

(0.1) of exceeding the calculated release

limits, and (2) have no more than a one

in one thousand (0.001) chance of

exceeding ten times the calculated

release limits.

In the process of reviewing the CCA,

the Agency found problems with some

computer codes and with

documentation of parameter
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27383

development. Commenters also voiced

concerns about some parameters used in

the CCA PA during the public comment

period for the Advanced Notice of

Proposed Rulemaking. The Conceptual

Models Peer Review Panel initially

found that one of the conceptual models

used for the PA, the spallings

conceptual model, was not adequate.

The DOE itself found some problems

with some of its codes, particularly

concerning code stability. Because of

these many concerns, the Agency

required DOE to perform additional

calculations in a Performance

Assessment Verification Test (‘‘PAVT’’)

in order to verify that the cumulative

impact of all changes to input

parameters, conceptual models, and

computer codes used in the PA was not

significant enough to necessitate a new

PA. (PAVT, Docket A–93–02, Items II–

G–26 and II–G–28) The PAVT used

modified parameter values and ranges,

selected by EPA, in DOE’s PA model.

Many of these parameter values were

suggested by public comments. The

PAVT results showed releases that were

higher, on average, than DOE’s original

calculations in the CCA. However, the

PAVT results were still well within the

EPA release limits stated in 40 CFR

191.13.

During the public comment period on

EPA’s proposed certification decision

for the WIPP, commenters raised several

issues about the PAVT and about the PA

in general. Some commenters stated that

the PAVT incorporated extremely

conservative ranges for 24 critical

parameters, and that the PA in general

was done in a conservative fashion.

Other commenters stated that specific

parameter values needed to be changed

in order to make more conservative

assumptions. In particular, the public

mentioned parameters for actinide

solubility, distribution coefficients (Kd),

the probability of hitting a brine pocket,

and the permeability of borehole plugs.

(These parameters are discussed above.)

Commenters also said that DOE needed

to investigate possible human intrusion

scenarios more thoroughly. Among the

human intrusion scenarios commenters

identified for further study were air

drilling, fluid injection, CO2 injection,

and potash mining. Members of the

public commented that DOE had

incorrectly assessed geology of the WIPP

site and the future state of the waste to

go into the WIPP. They stated concerns

about the potential for dissolution, for

the recharge of ground water in the

Rustler Formation with contaminated

brine, for earthquakes, and for water

entering the Salado layer and the

modeling of gas generation and flow of

brine and gas in the repository. Many

commenters stated that the Agency

should require DOE to run another PA

using different assumptions about these

topics.

The EPA initially had many of the

same concerns as those mentioned by

the public, particularly concerning

parameters and human intrusion

scenarios. As discussed in the above

preamble sections on the PA, EPA

questioned the values and distributions

of many values of the parameters. The

Agency even required DOE to revise

some parameter values for the PAVT.

The EPA also asked DOE to investigate

fluid injection further. After receiving

public comments, the Agency did

independent work on the possible

impacts of fluid injection and air

drilling, as well as analysis of the

likelihood of air drilling and CO2

injection in the Delaware Basin. (Docket

A–93–02, Item V–C–1, Sections 5 and 8)

After reviewing the information

available, the Agency concludes that

DOE’s PA incorporates the appropriate

human intrusion scenarios and geologic

and disposal system characteristics. The

PAVT and additional analyses of

intrusion scenarios by both DOE and

EPA have adequately addressed

concerns raised by commenters.

Based upon results of the CCA PA (as

confirmed by the PAVT), EPA finds that

the WIPP complies with the

containment requirements by a

comfortable margin, even when using

more conservative parameter values that

were changed significantly from those

in the CCA PA. This modeling shows

that the WIPP will contain waste safely

under realistic scenarios, and even in

many extreme cases. The EPA found

that the scenarios and parameter

changes suggested by commenters either

had already been adequately addressed

by DOE, were inappropriate for the

Delaware Basin, would impact neither

releases nor the results of the PA

sufficiently to justify further analysis, or

were not realistic. Therefore, the Agency

concludes that no further PA is required

to determine if the WIPP is safe or to

make its certification decision.

Many comments were based on a

philosophy that DOE should use an

unrealistically conservative approach to

the PA. For example, a commenter

stated that air drilling should be

incorporated in the PA at the most

conservative rate predicted by DOE in

the near future for the entire U.S., even

if air drilling is not currently a standard

practice in the Delaware Basin. Another

commenter suggested using the most

conservative value from the PAVT for

the probability of hitting a brine pocket,

even after the commenter’s own

sensitivity analysis showed that this

parameter did not have a significant

impact on WIPP compliance at still

higher values. A different commenter

stated that DOE and EPA should analyze

actinide solubilities as if DOE were not

adding MgO to reduce those solubilities,

even though the Department has

committed to adding MgO. The Agency

found all of these suggestions to be

inappropriate, either because they were

unrealistic or because they required

additional analysis when the change

had already been demonstrated to have

little or no impact on the PA results.

The Agency believes that the PA should

be a reasonable assessment with some

conservative assumptions built in,

rather than an assessment comprised

entirely of unrealistic assumptions and

worst-case scenarios. The disposal

regulations at 40 CFR Part 191 require

the PA to show there is a reasonable

expectation that cumulative releases

will meet the containment

requirements. This philosophy is

reflected elsewhere in EPA’s

requirements, such as in the

requirement for the mean CCDF to

comply with the containment

requirement, rather than for every CCDF

to comply. If unrealistically

conservative assumptions were used in

the PA, then results of the PA would not

reflect reality and would not be a

reasonable measure of the WIPP’s

capability to contain waste.

6. Conclusions

Section 194.23 sets forth specific

requirements for the models and

computer codes used to calculate the

results of performance assessments

(‘‘PA’’) and compliance assessments. In

order for these calculations to be

reliable, DOE must properly design and

implement the computer codes used in

the PA. To that end, § 194.23 requires

DOE to provide documentation and

descriptions of the PA models,

progressing from conceptual models

through development to mathematical

and numerical models, and finally to

their implementation in computer

codes.

The CCA and supporting documents

contain a complete and accurate

description of each of the conceptual

models used and the scenario

construction methods used. The

scenario construction descriptions

include sufficient detail to understand

the basis for selecting some scenarios

and rejecting others and are adequate for

use in the CCA PA calculations. Based

on information provided in the CCA,

together with supplementary

information provided by DOE in

response to specific EPA requests, EPA
27384 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

concluded that DOE provided an

adequate and complete description of

alternative conceptual models seriously

considered but not used in the CCA.

The information on peer review in the

CCA and in supplementary information

demonstrates that all conceptual models

have undergone peer review consistent

with the requirements of § 194.27.

Related issues discussed above in

today’s preamble include spallings,

fluid injection, air drilling, CO2

injection, and the gas generation

conceptual model. The Agency

determines that the DOE has

demonstrated compliance with the

requirements of §§ 194.23 (a)(1), (a)(2)

and (a)(3)(v).

The Conceptual Models Peer Review

Panel found all the conceptual models

to reasonably represent possible future

states of the repository and to be

adequate for use in the PA except the

spallings conceptual model. However,

as discussed above in this preamble,

additional modeling conducted by DOE,

and additional data presented by DOE,

provide a substantial basis for EPA to

conclude that the results of the spallings

model are adequate and useful for the

purpose for which conceptual models

are intended, i.e., to aid in the

determination of whether the WIPP will

comply with the disposal regulations

during the regulatory time period.

Public comments received on this issue

are discussed above in the preamble

section on spallings. Because the

spallings model produces reasonable

and conservative results, and because

the Peer Review Panel found that all

other conceptual models reasonably

represent possible future states of the

repository, EPA finds DOE in

compliance with § 194.23(a)(3)(i).

Based on information contained in the

CCA and supporting documentation for

each code, EPA concludes that the

mathematical models used to describe

the conceptual models incorporate

equations and boundary conditions

which reasonably represent the

mathematical formulation of the

conceptual models. Some of the specific

issues related to this criterion are in the

section of the preamble entitled, ‘‘Twodimensional modeling of brine and gas

flow.’’ Based on the CCA and

supplementary information provided by

DOE, the Agency determines that DOE

provided sufficient technical

information to document the numerical

models used in the CCA. Based on

verification testing, EPA also

determined that the computer codes

accurately implement the numerical

models and that the computer codes are

free of coding errors and produce stable

solutions. The DOE resolved coding

error problems and stability problems

identified in numerical models by

completing code revisions and

supplementary testing requested by the

Agency. Therefore, the Agency

concludes that DOE has demonstrated

compliance with §§ 194.23(a)(3) (ii), (iii)

and (iv).

Based on EPA audits and CCA review,

EPA found that code documentation

meets the quality assurance

requirements of ASME NQA–2a–1990

addenda, part 2.7, to ASME NQA–2–

1989 edition. Thus, the Agency finds

that DOE complies with § 194.23(b).

Based on DOE’s documentation for

each code and supplementary

information requested by EPA, the

Agency found that DOE provided

adequate documentation so that

individuals knowledgeable in the

subject matter have sufficient

information to judge whether the codes

are formulated on a sound theoretical

foundation, and whether the code has

been used properly in the PA. The EPA

found that the CCA and supplementary

information included an adequate

description of each model used in the

calculations; a description of limits of

applicability of each model; detailed

instructions for executing the computer

codes; hardware and software

requirements to run these codes; input

and output formats with explanations of

each input and output variable and

parameter; listings of input and output

files from sample computer runs; and

reports of code verification, bench

marking, validation, and QA

procedures. The EPA also found that

DOE adequately provided a detailed

description of the structure of the

computer codes and supplied a

complete listing of the computer source

code in supplementary documentation

to the CCA. The documentation of

computer codes describes the structure

of computer codes with sufficient detail

to allow EPA to understand how

software subroutines are linked. The

code structure documentation shows

how the codes operate to provide

accurate solutions of the conceptual

models. The EPA finds that DOE did not

use any software requiring licenses.

Therefore, EPA determines that DOE has

complied with the requirements of

§§ 194.23(c) (1),(2),(3) and (5).

The EPA determined that DOE, after

additional work and improvement of

records in the SNL Record Center,

adequately provided a detailed listing of

the code input parameters; listed

sampled input parameters; provided a

description of parameters and the codes

in which they are used; discussed

parameters important to releases;

described data collection procedures,

sources of data, data reduction and

analysis; and described code input

parameter development, including an

explanation of QA activities. The EPA

determined that the CCA and

supplementary information adequately

discussed how the effects of parameter

correlation are incorporated, explained

the mathematical functions that

describe these relationships, and

described the potential impacts on the

sampling of uncertain parameters. The

CCA also adequately documented the

effects of parameter correlation for both

conceptual models and the formulation

of computer codes, and appropriately

incorporated these correlations in the

PA. Public comments regarding

parameters are discussed above in the

preamble in the section titled

‘‘Parameter Values.’’ The Agency finds

that DOE has demonstrated compliance

with the requirements of § 194.23(c) (4)

and (6).

Because DOE provided EPA with

ready access to the necessary tools to

permit EPA to perform independent

simulations using computer software

and hardware employed in the CCA,

EPA finds DOE in compliance with

§ 194.23(d).

Section 194.31 of the compliance

criteria requires DOE to calculate release

limits for radionuclides in the WIPP in

accordance with 40 CFR Part 191,

Appendix A. Release limits are to be

calculated using the activity, in curies,

from radioactive waste that will exist in

the WIPP at the time of disposal. The

CCA PA and the PAVT were calculated

using release limits calculated according

to Appendix A of 40 CFR Part 191 using

DOE’s projected inventory of waste

radioactivity at the time of disposal.

Therefore, EPA concludes that DOE has

met the requirements of § 194.31.

Section 194.32 requires DOE to

consider, in the PA, both natural and

man-made processes and events which

can have an effect on the disposal

system. The EPA expected DOE to

consider all features, events and

processes (‘‘FEPs’’) that may have an

effect on the disposal system, including

both natural and human-initiated

processes. The Department is not

required to consider FEPs that have less

than one change in 10,000 of occurring

over 10,000 years.

The EPA concluded that the initial

FEP list assembled by DOE was

sufficiently comprehensive, in

accordance with §§ 194.32(a) and (e)(1).

Based on quantitative and qualitative

assessments provided in the CCA and

supporting documents, EPA concluded

that DOE appropriately rejected those

FEPs that exhibit low probability of

occurrence during the regulatory period,
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27385

in accordance with § 194.32(d). In

addition, EPA found DOE’s inclusion of

various scenarios in the PA to be

reasonable and justified, and meets the

requirement of § 194.32(e)(2). The DOE

provided documentation and

justification for eliminating those FEPs

that were not included in the PA. In

some cases (e.g., fluid injection, CO2

injection, potash mining and

dissolution), the CCA did not initially

provide adequate justification or

convincing arguments to eliminate FEPs

from consideration in the PA. However,

DOE provided supplemental

information and analyses, which EPA

determined was sufficient to

demonstrate compliance with

§ 194.32(e)(3).

The EPA verified, through review of

the CCA and supporting documents,

that DOE included, in the PA,

appropriate changes in the hydraulic

conductivity values for the areas

affected by mining. The area considered

to be mined for potash in the controlled

area is consistent with the requirement

of § 194.32(b), that the mined area be

based on mineral deposits of those

resources currently extracted from the

Delaware Basin. Thus, EPA finds that

DOE complies with § 194.32(b).

In accordance with § 194.32(c), DOE

considered the possibility of fluid

injection, identified oil and gas

exploration and exploitation, and water

and potash exploration as the only near

future human-initiated activities that

need to be considered in the PA. The

EPA’s review of the CCA and supporting

documents referenced in the CCA with

respect to § 194.32(c), indicated that

DOE adequately analyzed the possible

effects of current and future potential

activities on the disposal system. In

response to concerns expressed by EPA

and stakeholders, DOE conducted

additional analyses and submitted

follow-up information. In addition, EPA

has performed its own analysis of fluid

injection. Public comments concerning

human intrusion FEPs are discussed in

the preamble sections above titled,

‘‘Fluid injection,’’ ‘‘Potash mining,’’ and

‘‘CO2 injection.’’ The collected

information provided by DOE was

adequate. Therefore, EPA concludes that

DOE’s analysis meets the requirements

of § 194.32(c).

Section 194.33 requires DOE to make

specific assumptions about future deep

and shallow drilling in the Delaware

Basin. The EPA found that the

documentation in the CCA

demonstrated that DOE thoroughly

considered deep and shallow drilling

activities and rates within the Delaware

Basin in accordance with § 194.33 (a)

and (b). The EPA found that DOE

appropriately screened out shallow

drilling from consideration in the PA.

The EPA also found that DOE

appropriately incorporated the

assumptions and calculations for

drilling into the PA as stipulated in

§§ 194.33 (b) and (c). In accordance with

§ 194.33(c), DOE evaluated the

consequences of drilling events

assuming that drilling practices and

technology remain consistent with

practices in the Delaware Basin at the

time the certification application was

prepared. Public comments concerning

this issue are discussed in the preamble

section above titled, ‘‘Air drilling.’’ The

EPA determined that the PA models did

not incorporate the effects of techniques

used for resource recovery, as allowed

by § 194.33(d). The EPA further

concludes that the drilling information

in the CCA is consistent with available

data. Therefore, the Agency finds DOE

in compliance with the requirements of

§ 194.33.

Section 194.34 of the compliance

criteria provides specific requirements

for presenting the results of the PA for

the WIPP. Section 194.34 requires DOE

to use complementary cumulative

distribution functions (‘‘CCDFs’’) to

express the results of the PA. The

Department also must document the

development of probability

distributions, and the computational

techniques used for drawing random

samples from these probability

distributions, for any uncertain

parameters used in the PA. The PA must

include a statistically sufficient number

of CCDFs. The CCA must display the

full range of CCDFs generated. Finally,

the CCA must demonstrate that the

mean of the population of CCDFs meets

the containment requirements of

§ 191.13 with at least a 95 percent level

of statistical confidence.

The CCA presented the results of the

PA in the form of CCDFs. The PA used

Latin Hypercube Sampling to sample

values randomly from probability

distributions of uncertain parameters.

Parameter values and their distributions

were documented in the CCA and in

Sandia National Laboratory’s Records

Center. The CCA presented the full

range of the 300 CCDFs generated in the

PA, as well as mean CCDF curves. The

CCDFs showed that the mean CCDF

curve met the containment requirements

of § 191.13. Less than one percent of

CCDF curves in the CCA PA exceeded

one times the release limit, and no

CCDF curves exceeded ten times the

release limit. Based on these results,

DOE concluded that the WIPP met

EPA’s requirements.

The EPA also examined the results of

the PAVT in light of the requirements of

§ 194.34. The PAVT presented the

results of the PA in CCDFs, and

presented the complement of 300

CCDFs. DOE’s documentation and

EPA’s separate analysis demonstrated

that 300 CCDFs are sufficient,

statistically speaking. The PAVT used

the same random sampling technique of

Latin Hypercube Sampling that the PA

model used for the CCA PA. The DOE

used parameter values assigned by EPA,

as well as other parameter values and

their distributions documented earlier

for the CCA PA. The mean CCDF curve

for the PAVT showed that releases were

roughly three times those calculated in

the CCA PA, but releases still met the

containment requirements of § 191.13

by more than an order of magnitude at

the required statistical confidence level.

Less than ten percent of CCDF curves in

the PAVT exceeded one times the

release limit, and no CCDF curves

exceeded ten times the release limit.

The PAVT confirmed that the CCA PA

was adequate for determining

compliance. Therefore, EPA concludes

that the CCA PA meets EPA’s

containment requirements and that DOE

complies with the requirements of

§ 194.34.

C. General Requirements

1. Quality Assurance (§ 194.22)

Section 194.22 establishes quality

assurance (‘‘QA’’) requirements for the

WIPP. QA is a process for enhancing the

reliability of technical data and analyses

underlying DOE’s CCA. Section 194.22

requires DOE to (a) establish and

execute a QA program for all items and

activities important to the containment

of waste in the disposal system, (b)

qualify data that were collected prior to

implementation of the required QA

program, (c) assess data for their quality

characteristics, to the extent practicable,

(d) demonstrate how data are qualified

for their use, and (e) allow verification

of the above measures through EPA

inspections/audits. The DOE’s QA

program must adhere to specific Nuclear

Quality Assurance (‘‘NQA’’) standards

issued by the American Society of

Mechanical Engineers (‘‘ASME’’).

The EPA assessed compliance with

the QA requirements in two ways. First,

EPA reviewed general QA information

submitted by DOE in the CCA and

reference documents. The EPA’s second

level of review consisted of visits to the

WIPP site, as well as WIPP-related

facilities, to perform independent audits

and inspections to verify DOE’s

compliance with the QA requirements.

The proper establishment and execution

of a QA program is verified strictly by

way of inspections and audits.
27386 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

30NQA–1 (Element II–2) requires that

organizations responsible for activities affecting

quality (in the case of the WIPP, affecting the

containment of waste in the disposal system) must

have documented QA programs in accordance with

the applicable NQA requirements. The

documentation for such programs is commonly

referred to as a ‘‘quality assurance program plan,’’

or ‘‘QAPP.’’ For WIPP waste generator sites, the role

of the QAPP is fulfilled by documents with other

titles, such as the QAP and the QAPjP. The ‘‘TRU

QAPP’’ referenced by DOE in the CCA is not a

QAPP as described by the NQA standards; rather,

it is a technical document that describes the quality

control requirements and performance standards for

characterization of TRU waste coming to the WIPP

facility. The TRU QAPP is addressed more

specifically in the preamble discussion of § 194.24,

Waste Characterization.

31The terms ‘‘audits’’ and ‘‘inspections’’ are not

synonymous. At waste generator sites, EPA may

either conduct its own audits or inspect audits

conducted by DOE. (The DOE–CAO conducts audits

to evaluate waste characterization programs at

waste generator sites.) The difference is that for an

inspection, EPA’s role is to review DOE’s QA

checks, and not actually conduct all of the checks

itself.

Therefore, EPA conducted audits to

verify the proper execution of the QA

program at DOE’s Carlsbad Area Office

(‘‘CAO’’), Sandia National Laboratories

(‘‘SNL’’), and Westinghouse’s Waste

Isolation Division (‘‘WID’’) at the WIPP

facility. The EPA auditors observed

WIPP QA activities, interviewed WIPP

personnel, and reviewed voluminous

records required by the NQA standards,

but not required to be submitted as part

of the CCA.

Section 194.22(a)(1) requires DOE to

adhere to a QA program that

implements the requirements of the

following: (1) ASME NQA–1–1989

edition; (2) ASME NQA–2a–1990

addenda, part 2.7, to ASME NQA–2–

1989 edition; and (3) ASME NQA–3–

1989 edition (excluding Section 2.1 (b)

and (c), and Section 17.1). The EPA

verified that DOE established these

requirements in the Quality Assurance

Program Document (‘‘QAPD’’) contained

in the CCA. The QAPD is the

documented QA program plan for the

WIPP project, as a whole, to comply

with the NQA requirements. The QAPD

is implemented by DOE’s CAO, which

has the authority to audit all other

organizations associated with waste

disposal at the WIPP (such as WID, SNL

and waste generator sites) to ensure that

their lower-tier QA programs establish

and implement the applicable

requirements of the QAPD. The EPA

audited DOE’s QA program at CAO and

determined that DOE properly adhered

to a QA program that implements the

NQA standards. Therefore, EPA finds

DOE in compliance with § 194.22(a)(1).

Section 194.22(a)(2) requires DOE to

include information in the CCA that

demonstrates that the requisite QA

program has been ‘‘established and

executed’’ for a number of specific

activities. Section 194.22(a)(2)(i)

requires DOE to include information

which demonstrates that the QA

program has been established and

executed for waste characterization

activities and assumptions. In the CCA,

DOE provided the QAPD, which is

DOE’s central QA document program

plan that then must be incorporated into

site-specific QA program plans. The

DOE generator sites will prepare site

certification Quality Assurance Plans

(‘‘QAPs’’) that, together with Quality

Assurance Project Plans (‘‘QAPjPs’’),

will constitute site-specific QA program

plans.30 The EPA finds that the QAPD,

as it applies to waste characterization, is

in conformance with the NQA

requirements and that DOE’s QA

organization can properly perform

audits to internally check the QA

programs of the waste generator sites.

However, as discussed below, the

Agency will verify the establishment

and execution of site-specific QA

programs.

The compliance criteria require that

QA programs be established and

executed specifically with respect to the

use of process knowledge and a system

of controls for waste characterization.

(§§ 194.22(a)(2)(i) and 194.24(c)(3)

through (5)) To accomplish this, waste

generator site-specific QA programs and

plans must be individually examined

and approved by EPA to ensure

adequate QA programs are in place

before EPA allows individual waste

generator sites to transport waste for

disposal at the WIPP. Since waste

characterization activities have not

begun for most TRU waste generator

sites and storage facilities, EPA has not

yet evaluated the compliance of many

site-specific QA plans and programs.

To date, one WIPP waste generator

site, Los Alamos National Laboratory

(‘‘LANL’’), has been approved by EPA to

have established an adequate QA

program plan and to have properly

executed its QA program in accordance

with the plan. Prior to approval of

LANL’s site-specific QA program, EPA

conducted an audit of DOE’s overall

WIPP QA program and approved its

capability to perform audits in

accordance with the requirements of

NQA–1. The EPA then inspected three

DOE audits of LANL’s QA program.

Based on the results of the inspections,

the EPA inspectors determined that the

QA program had been properly

executed at LANL.31 Therefore, EPA

finds that the requirements of

§ 194.22(a)(2)(i) have been met for waste

characterization activities at LANL.

With respect to other waste generator

sites, EPA will verify compliance with

§ 194.22(a)(2)(i) conditioned on

separate, subsequent approvals from

EPA that site-specific QA programs for

waste characterization activities and

assumptions have been established and

executed in accordance with applicable

NQA requirements at each waste

generator site.

As waste generator facilities establish

QA programs after LANL, EPA will

assess their compliance with NQA

requirements. The approval process for

site-specific QA programs includes a

Federal Register notice, public

comment period, and on-site EPA audits

or inspections to evaluate

implementation. For further information

on EPA’s approval process, see

Condition 2 and § 194.8. For further

discussion of waste characterization

programs and approval of the processes

used to characterize waste streams from

generator sites, see the discussion of

§ 194.24 below in this preamble.

Section 194.22(a)(2)(ii) requires DOE

to include information which

demonstrates that the QA program has

been established and executed for

environmental monitoring, monitoring

of performance of the disposal system

and sampling and analysis activities.

Westinghouse’s WID was responsible for

establishing this requirement under the

WID QAPD described in the CCA. The

EPA conducted an audit of the WID and

found that the requisite QA program

had been established and executed for

environmental monitoring, sampling

and analysis activities. The EPA also

finds that Chapter 5 of the CCA and

referenced documents contain a

satisfactory description of compliance

with this section. Therefore, EPA finds

the WIPP in compliance with

§ 194.22(a)(2)(ii).

Section 194.22(a)(2)(iii) requires DOE

to include information which

demonstrates that the QA program has

been established and executed for field

measurements of geologic factors,

ground water, meteorologic, and

topographic characteristics. WID is

responsible for conducting field

measurements of geologic factors,

ground water, meteorologic and

topographic characteristics. The EPA

conducted an audit of the WID QA

program and found it to be properly

established and executed in accordance

with the applicable NQA requirements.

The EPA also finds that Chapter 5 of the

CCA and referenced documents contain

a satisfactory description of compliance

with this section. Therefore, EPA finds

DOE in compliance with

§ 194.22(a)(2)(iii).
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27387

Section 194.22(a)(2)(iv) requires DOE

to include information to demonstrate

that the QA program has been

established and executed for

computations, computer codes, models

and methods used to demonstrate

compliance with the disposal

regulations. SNL and WID are

responsible for computations and

software items. The EPA reviewed

information in the CCA and conducted

audits of both SNL and WID QA

programs. The Agency found that

computer codes were documented in a

manner that complies with the

applicable NQA requirements, and that

software QA procedures were

implemented in accordance with ASME

NQA–2a, part 2.7. The EPA also finds

that Chapter 5 of the CCA and

referenced documents contain a

satisfactory description of compliance

with this section. The EPA therefore

finds that DOE complies with

§ 194.22(a)(2)(iv).

Section 194.22(a)(2)(v) requires DOE

to include information which

demonstrates that the QA program has

been established and executed for

procedures for implementation of expert

judgment elicitation. CAO and CAO’s

Technical Assistance Contractor were

responsible for developing the

procedures for the expert elicitation that

was conducted (after the publication of

the CCA). The EPA found that the

requirements of this regulation were met

by the development and

implementation of CAO Team

Procedure 10.6 (Revision 0), CAO Team

Plan for Expert Panel Elicitation

(Revision 2), and CAO Technical

Assistance Contractor Experimental

Programs Desktop Instruction No.1

(Revision 1). The EPA finds DOE in

compliance with § 194.22(a)(2)(v). The

process of expert judgment elicitation is

discussed in further detail in the section

of this preamble related to § 194.26 of

the compliance criteria.

Section 194.22(a)(2)(vi) requires DOE

to include information which

demonstrates that the QA program has

been established and executed for

design of the disposal system and

actions taken to ensure compliance with

the design specifications. Most of the

WIPP’s design was conducted before the

EPA required a QA program. Design

work for the repository sealing system

was conducted under the SNL QA

program. The QA procedures

established and implemented by SNL

and WID address the requirements of

the NQA standards; design verification

was accomplished by a combination of

NQA–1 Supplement 3S–1 methods. The

EPA audits of SNL and WID showed

that the QA programs are properly

established and executed. The EPA also

finds that Chapter 5 of the CCA and

referenced documents contain an

adequate description of compliance

with this section. Therefore, EPA finds

DOE in compliance with

§ 194.22(a)(2)(vi).

Section 194.22(a)(2)(vii) requires DOE

to include information which

demonstrates that the QA program has

been established and executed for the

collection of data and information used

to support compliance applications.

SNL was responsible for this activity.

SNL adequately addressed these

requirements by implementing

numerous QA procedures to ensure the

quality of data and information

collected in support of the WIPP. The

EPA’s audit of SNL concluded that the

QA program is properly established and

executed. Therefore, EPA finds DOE in

compliance with § 194.22(a)(2)(vii).

Section 194.22(a)(2)(viii) requires

DOE to include information which

demonstrates that the QA program has

been established for any other item or

activity not listed above that is

important to the containment of waste

in the disposal system. The DOE has not

identified any other item or activity

important to waste isolation in the

disposal system that require QA

controls to be applied as described in

the CAO QAPD. To date, the EPA has

also not identified any other items or

activities which require controls. The

EPA audits determined that the QA

organizations of CAO, WID, and SNL

have sufficient authority, access to work

areas, and organizational freedom to

identify other items and activities

affecting the quality of waste isolation.

Therefore, EPA finds DOE in

compliance with § 194.22(a)(2)(viii).

Section 194.22(b) requires DOE to

include information which

demonstrates that data and information

collected prior to the implementation of

the QA program required by

§ 194.22(a)(1) have been qualified in

accordance with an alternate

methodology, approved by the

Administrator or the Administrator’s

authorized representative, that employs

one or more of the following methods:

peer review; corroborating data;

confirmatory testing; or a QA program

that is equivalent in effect to

§ 194.22(a)(1) ASME documents.

The EPA conducted two audits that

traced new and existing data to their

qualifying sources. The two audits

found that equivalent QA programs and

peer review had been properly applied

to qualify existing data used in the PA.

The EPA also concluded that the use of

existing data from peer-reviewed

technical journals was appropriate,

since the level of such reviews was

equivalent to NUREG–1297 peer

reviews conducted by DOE. Therefore,

EPA finds DOE in compliance with

§ 194.22(b). Furthermore, the Agency is

approving the use of any one of the

following three methods for

qualification of existing data: (1) peer

review, conducted in a manner that is

compatible with NUREG–1297; (2) a QA

program that is equivalent in effect to

ASME NQA–1–1989 edition, ASME

NQA–2a–1990 addenda, part 2.7, to

ASME NQA–2–1989 edition, and ASME

NQA–3–1989 edition (excluding Section

2.1(b) and (c) and Section 17.1); or (3)

use of data from a peer-reviewed

technical journal.

Sections 194.22(c)(1) through (5)

require DOE to provide information

which describes how all data used to

support the compliance application

have been assessed, to the extent

practicable, for specific data quality

characteristics (‘‘DQCs’’). In the CCA,

DOE stated that in most cases it was not

practicable to document DQCs for

performance assessments, but asserted

that the intent of DQCs was fulfilled by

other QA programs and quality control

measures.

The Agency agrees with DOE that it

is not appropriate to apply DQCs

retroactively to all of the parameters and

existing data used in the PA, but

believes that they can and should be

applied to measured data (i.e., field

monitoring and laboratory experiments)

as they are developed and used. The

EPA found that, because DOE deemed it

impractical to apply DQCs in some

instances, the CCA and supplementary

information did not systematically or

adequately address DOE’s consideration

of DQCs for measured data related to the

PA. Therefore, EPA reviewed parameter

records to determine whether DOE

could in fact show that various data

quality characteristics had been

considered for measured data. The

Agency reviewed additional materials,

primarily data record packages at the

SNL records center, to independently

determine whether DQCs had been

assessed for data used in the PA. The

EPA found that for recent data (five to

ten years old), DOE’s experimental

program plans in the data record

packages generally addressed data

quality in measured data, including

accuracy, precision, representativeness,

completeness, and comparability during

measurement and collection.

For older existing data, EPA found

less documentation of assessment of

DQCs. However, laboratory

notebooks’which provide first-hand

documentation of measurement

procedures and results’supporting data
27388 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

record packages provided some

information related to the quality of

measurements (e.g., how well DOE’s

measured values compared with values

found in peer-reviewed publications).

Many existing data were also subject to

peer review in order to qualify them for

use in the CCA; EPA concluded that the

peer review panels considered the use

of DQCs in determining that such data

were adequate. The EPA also agreed

with DOE’s argument in supplementary

information that for most of the existing

data, collection under a program

equivalent to the NQA standards in

§ 194.22(a)(1) provided adequate

evidence that the quality of data had

been evaluated and controlled. Finally,

EPA concurred with DOE’s conclusion

that the uncertainties in measured data

reflected in DQCs have a small effect on

compliance certainty, compared to other

uncertainties in the PA (such as

extrapolation of processes over 10,000

years).

The EPA found that data quality

received considerable attention from

peer reviewers and Independent Review

Teams assembled by DOE, and was

subject to NQA requirements as

specified in the Quality Assurance

Program Document (‘‘QAPD’’). Section

§ 194.22(a) requires DOE to implement

NQA–3–1989 in its quality assurance

program. NQA–3–1989 states, ‘‘Planning

shall establish provisions for data

quality evaluation to assure data

generated are valid, comparable,

complete, representative, and of known

precision and accuracy.’’ This

requirement was satisfactorily

incorporated in the QAPD, which is the

quality assurance ‘‘master’’ document

that establishes QA requirements for all

activities overseen by the DOE Carlsbad

Area Office. The EPA determined by

means of audits that DOE adequately

implemented the requirements of the

QAPD, and also determined that DOE

adequately qualified existing data in

accordance with Section § 194.22(b).

(See Docket A–93–02, Item V–B–2,

CARD 22, Sections 22.A.6 and 22.J.5.)

Therefore, EPA finds that DOE’s data

qualification was sufficiently rigorous to

account for the DQCs identified in the

WIPP compliance criteria.

Based on its review of data record

packages and the QAPD, the Agency

finds that DOE has assessed DQCs, to

the extent practicable, for data used in

the CCA. The EPA thus finds that DOE

complies with § 194.22(c). The Agency

expects that DOE will assess DQCs for

future waste characterization and

monitoring activities.

Section 194.22(d) requires DOE to

provide information which describes

how all data are qualified for use. SNL

generated a table providing information

of how all data in the PA were qualified.

The EPA audited the existing QA

programs and determined that the data

were qualified for use by independent

and qualified personnel in accordance

with NQA requirements. On this basis,

EPA finds DOE in compliance with

§ 194.22(d).

Section 194.22(e) allows EPA to verify

execution of QA programs through

inspections, record reviews, and other

measures. As discussed above, EPA has

conducted numerous audits of DOE

facilities, and intends to conduct future

inspections of waste generator sitespecific QA plans under its authority.

The Agency also intends to conduct

inspections or audits to confirmed

DOE’s continued adherence to QA

requirements for which EPA is

certifying compliance.

In summary, EPA finds DOE in

compliance with the requirements of

§ 194.22 subject to the condition that

EPA separately approve the

establishment and execution of sitespecific QA programs for waste

characterization activities at waste

generator sites. (See Condition 2 of the

proposed Appendix A to 40 CFR Part

194.)

The EPA received many public

comments on § 194.22, but the most

significant issue identified by

commenters was the lack of objective

evidence in the CCA to justify meeting

the requirements at § 194.22(a)(2). The

comments posed the fundamental

question of whether or not EPA could

certify, based solely on information

provided by DOE in the CCA, that DOE

established and executed a QA program

for the eight areas considered important

to the containment of waste in the

disposal system. In response to such

concerns, EPA believes it is necessary to

explain and clarify the verification of

these QA requirements.

The CCA does not alone provide all

the documentation to verify compliance

with the requirement of § 194.22(a)(2).

Section § 194.22(e) requires EPA to

verify that DOE has established and

executed a QA program for the areas

indicated in § 194.22(a)(2). The

‘‘objective evidence’’ for determining

whether or not a QA program has been

established and executed exists at the

WIPP-related facilities and generator

sites, and is gathered in the field audits

and inspections. The function of the

audits and inspections is to gather

objective evidence to determine

compliance of the QA programs with

the applicable NQA standards.

Several WIPP organizations are

responsible for establishing and

executing the activities and items listed

in the eight areas of § 194.22(a)(2). The

CCA states that DOE provides the

overall QA program requirements for

WIPP via the CAO QAPD. The CAO

QAPD requirements are further

supported and amplified by the next tier

of QA program documents, which

includes the SNL quality assurance

procedures (SNL QAPs), the WID

Quality Assurance Program Description,

and the individual site quality

assurance program plans (e.g., QAPjPs).

More documentation is found in DOE,

WID and SNL implementing procedures

and QA records. For example,

‘‘Corrective Action Reports’’ and ‘‘Audit

Reports’’ provide objective evidence of

implementation of certain NQA

elements. Therefore, EPA finds that

sufficient information for compliance

with § 194.22(a)(2)(ii)–(viii), and for QA

program implementation for waste

characterization activities at LANL

(§ 194.22(a)(2)(i)) was provided in the

CCA and supporting documents to the

extent practical.

The EPA verified that QA programs

were established in accordance with

§ 194.22 through the CAO QAPD and

supporting documents. The EPA

expected to find objective evidence of

compliance or noncompliance with the

QA requirements within the QA records

and activities of the WIPP organizations,

including CAO, SNL, and WID. In

accordance with § 194.22(e), the Agency

conducted audits of these WIPP

organizations to verify the appropriate

execution of QA programs. (Docket A–

93–02; Items II–A–43, II–A–44, II–A–45,

II–A–46, II–A–47, II–A–48, and II–A–49)

Documentation of evidence of audits

that verified the execution of the QA

programs is found in EPA’s audit

reports. The EPA’s audits of CAO, SNL,

and WID covered all aspects of the

programs including, but not limited to:

the adoption of the requirements of

§ 194.22 through the CAO QAPD,

quality assurance procedures (‘‘QAPs’’),

reports from previous audits,

surveillance reports, and corrective

action reports (‘‘CARs’’). The audits

assessed the adequacy and

implementation of the SNL and WID

quality assurance programs in

accordance with the requirements of

§ 194.22(a)(1). For example, for

§ 194.22(a)(2)(iv), the ‘‘computations,

computer codes, models and methods

used to demonstrate compliance with

the disposal regulations,’’ EPA

conducted audits of the SNL and WID

quality assurance programs for

computations, computer codes, methods

and models. For all of the other areas in

§ 194.22(a)(2), CARD 22 (Section 22.B)

should be consulted for information and
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27389

citations to audit reports. (Docket A–93–

02, Item V–B–2)

In summary, EPA certifies compliance

with the eight areas in § 194.22(a)(2)

through inspections and audits. Most of

the evidence demonstrating compliance

is found at the WIPP-related facilities

and generator sites. Such evidence was

unreasonable to include in the CCA due

to the voluminous nature of the

information.

2. Waste Characterization (§ 194.24)

Section 194.24, waste

characterization, generally requires DOE

to identify, quantify, and track the

chemical, radiological and physical

components of the waste destined for

disposal at the WIPP that can influence

disposal system performance.

Section 194.24(a) requires DOE to

describe the chemical, radiological and

physical composition of all existing and

to-be-generated waste, including a list of

waste components and their

approximate quantities in the waste.

The DOE provided the required

information on existing waste (35% of

the total WIPP inventory) by combining

similar waste streams into waste stream

profiles. The waste stream profiles

contain information on the waste

material parameters, or components,

that could affect repository

performance. For to-be-generated waste

(65% of the total WIPP inventory), DOE

extrapolated information from the

existing waste streams to determine the

future amount of waste. The EPA

reviewed this information and

determined that DOE’s waste stream

profiles contained the appropriate

specific information on the components

and their approximate quantities in the

waste. Therefore, EPA finds DOE in

compliance with § 194.24(a).

Section 194.24(b) requires DOE to

analyze waste characteristics and waste

components for their impact on disposal

system performance. Waste components

affect waste characteristics and are

integral to disposal system performance.

The DOE identified waste-related

elements pertinent to the WIPP as part

of its screening for features, events, and

processes. The features, events, and

processes used in the performance

assessment (‘‘PA’’) served as the basis

from which characteristics and

associated components were identified

and further analyzed. (For further

information on features, events, and

processes, see Docket A–93–02, Item V–

B–2, CARD 32; and the above preamble

sections related to the PA.)

The DOE concluded that six

characteristics were expected to have a

significant effect on disposal system

performance and were used in the PA as

parameters or in conceptual models:

solubility, formation of colloidal

suspensions containing radionuclides,

gas generation, shear strength of waste,

radioactivity of specific isotopes, and

transuranic (‘‘TRU’’) activity at disposal.

The DOE identified eight waste

components influencing the six

significant waste characteristics: ferrous

metals, cellulose, radionuclide

identification, radioactivity of isotopes,

TRU activity of waste, solid waste

components, sulfates, and nitrates.

Finally, DOE provided a list of waste

characteristics and components

assessed, but determined not to be

significant for various reasons such as

negligible impact on the PA. The EPA

found that DOE used a reasonable

methodology to identify and assess

waste characteristics and components.

The analysis appropriately accounted

for uncertainty and the quality of

available information. Therefore, EPA

finds DOE in compliance with

requirements in § 194.24(b).

Section 194.24(c)(1) requires DOE to

specify numeric limits on significant

waste components and demonstrate

that, for those component limits, the

WIPP complies with the numeric

requirements of §§ 194.34 and 194.55.

Either upper or lower limits were

established for components that must be

controlled to ensure that the PA results

comply with the containment

requirements. The DOE explicitly

included numeric limits, identified as

fixed values with no associated

uncertainty, for four waste components.

Lower limits were established for (1)

ferrous and (2) non-ferrous metals (not

included in DOE’s original list of

components, but added later due to its

binding effect on organic ligands); upper

limits were established for (3)

cellulosics and (4) free water (not

included in DOE’s original list of

components, but added later due to its

inclusion in the Waste Acceptance

Criteria).

The three components related to

radioactivity (radionuclide

identification, radioactivity of isotopes,

TRU activity of waste) were effectively

limited by the inventory estimates used

in the PA and the WIPP LWA fixedvalue limits. Both the PA inventory

estimates and the WIPP LWA fixedvalue limits were included in the PA

calculations through parameters closely

related to these components, and the

results demonstrated compliance with

EPA’s standards.

Explicit limits were not identified for

solid waste, sulfates, and nitrates, even

though DOE identified these as

components significant to performance.

For solid waste, EPA determined that in

the PA, DOE took no credit for the

potential gas-reducing effects of solid

waste (i.e., assumed a lower limit of

zero) and demonstrated that the WIPP

would still comply. For nitrates and

sulfates, EPA determined that these

components would not significantly

affect the behavior of the disposal

system as long as cellulosics were

limited. Thus, EPA concurred that it is

unnecessary to specify limits for

nitrates, sulfates, and solid waste.

The EPA finds DOE in compliance

with § 194.24(c)(1). The EPA concurred

with DOE that it was not necessary to

provide estimates of uncertainty for

waste limits, so long as the PA

demonstrated compliance at the fixed

limits. However, since DOE’s waste

limits do not address uncertainty, the

Department must account for

uncertainty in the quantification of

waste components when tracking

compliance with the waste limits. That

is, the fixed waste limits essentially

constitute an upper confidence level (in

the case of limits on the maximum

amount of a waste component) or a

lower confidence level (in the case of

limits on the minimum amount of a

component) for measurements or

estimates of waste components that

must be tracked. The DOE must

demonstrate that the characterized

waste components, including associated

uncertainty (i.e., margin of error), meet

the fixed waste component limits.

Section 194.24(c)(2) requires DOE to

identify and describe the methods used

to quantify the limits of important waste

components identified in § 194.24(b)(2).

The DOE proposed to use nondestructive assay (‘‘NDA’’), nondestructive examination (‘‘NDE’’), and

visual examination (‘‘VE’’) as the

methods used to quantify various waste

components. (See Docket A–93–02, Item

V–B–2, CARD 24, Section 24.F.1 for

further information about the methods.)

The DOE described numerous NDA

instrument systems and described the

equipment and instrumentation found

in NDE and VE facilities. The DOE also

provided information about

performance demonstration programs

intended to show that data obtained by

each method could meet data quality

objectives established by DOE. The EPA

found that these methods, when

implemented appropriately, would be

adequate to characterize the important

waste components. Therefore, EPA finds

DOE in compliance with § 194.24(c)(2).

Section 194.24(c)(3) requires DOE to

demonstrate that the use of process
27390 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

32Process knowledge refers to knowledge of waste

characteristics derived from information on the

materials or processes used to generate the waste.

This information may include administrative,

procurement, and quality control documentation

associated with the generating process, or past

sampling and analytic data. Usually, the major

elements of process knowledge include information

about the process used to generate the waste,

material inputs to the process, and the time period

during which the waste was generated.

33See Docket A–93–02, Item II–I–70 for a list of

the systems and processes audited by DOE. See

Docket A–93–02, Item II–I–51 for a description of

the waste identifier and a discussion of the items

and activities inspected by EPA. They include

characterization methodologies and relevant

procedures, such as that used for entering data into

the WWIS database.

knowledge 32 to quantify components in

waste for disposal conforms with the

quality assurance (‘‘QA’’) requirements

found in § 194.22. The DOE did not

submit site-specific information on the

process knowledge to be used at waste

generator sites as part of the CCA. The

EPA requires such information to

conduct proper review of whether use of

the process knowledge is appropriate

and reliable. The DOE provided some

information on its overall plans for

using process knowledge in the CCA.

The DOE did not, however, provide

specific information on the use of

process knowledge or Acceptable

Knowledge (‘‘AK’’—hereafter only ‘‘AK’’

is used; process knowledge is a subset

of acceptable knowledge) at any waste

generator site in the CCA, nor did it

provide information demonstrating

establishment of the required QA

programs.

After submission of the CCA, EPA

subsequently received information

regarding AK to be used at the Los

Alamos National Laboratory (‘‘LANL’’).

The EPA determined that DOE

adequately described the use of AK for

legacy debris waste at LANL. The EPA

has confirmed establishment and

execution of the required QA programs

at that waste generator site through

inspections. Therefore, EPA finds that

DOE has demonstrated compliance with

the § 194.24(c)(3) QA requirement for

LANL. The EPA does not find, however,

that DOE has adequately described the

use of AK for any waste at LANL other

than the legacy debris waste which can

be characterized using the processes

examined in EPA’s inspection. (See

Docket A–93–02, Item V–B–15 for

further information on the conclusions

of EPA’s inspection. See Docket A–93–

02, Item II–I–70 for a list of the items

and processes inspected by EPA.)

Furthermore, DOE has not demonstrated

compliance with § 194.24(c)(3) for any

other waste generator site. For any

LANL waste streams using other

characterization processes or any other

waste generator site, before waste can be

shipped to the WIPP, EPA must

determine that the site has provided

information on how AK will be used for

waste characterization of the waste

stream(s) proposed for disposal at the

WIPP. Condition 3 of the final rule

embodies this limitation. The sitespecific use of process knowledge must

conform with QA requirements, as

addressed by Condition 2. (For further

information on EPA’s approval process,

see § 194.8, ‘‘Approval Process for

Waste Shipment from Waste Generator

Sites for Disposal at the WIPP.’’)

Sections 194.24(c) (4) and (5) require

DOE to demonstrate that a system of

controls has been and will continue to

be implemented to confirm that the

waste components emplaced in the

WIPP will not exceed the upper limit or

fall below the lower limit calculated in

accordance with § 194.24(c)(1) and that

the system of controls conforms to the

QA requirements specified in § 194.22.

The DOE described a system of controls

over waste characterization activities,

such as the requirements of the TRU QA

Program Plan (‘‘TRU QAPP’’) and the

Waste Acceptance Criteria (‘‘WAC’’).

The EPA found that the TRU QAPP

established appropriate technical

quality control and performance

standards for sites to use in developing

site-specific sampling plans. Further,

DOE outlined two phases in waste

characterization controls: (1) waste

stream screening/verification (preshipment from waste generator site);

and (2) waste shipment screening/

verification (pre-receipt of waste at the

WIPP). The tracking system for waste

components against their upper and/or

lower limits is found in the WIPP Waste

Information System (‘‘WWIS’’). The EPA

finds that the TRU QAPP, WAC, and

WWIS are adequate to control important

components of waste emplaced in the

WIPP. The EPA audited DOE’s QA

programs at Carlsbad Area Office,

Sandia National Laboratory and

Westinghouse Waste Isolation Division

and determined that DOE properly

adhered to QA programs that implement

the applicable Nuclear Quality

Assurance standards and requirements.

(See the preamble discussion of

§ 194.22, Quality Assurance, for further

information.) However, in the CCA,

DOE did not demonstrate that the WWIS

is fully functional and did not provide

information regarding the specific

system of controls to be used at

individual waste generator sites.

After submission of the CCA, EPA

subsequently received information

regarding the system of controls

(including measurement techniques) to

be used at LANL. The Agency

confirmed through inspections that the

system of controls—and in particular,

the measurement techniques—is

adequate to characterize waste and

ensure compliance with the limits on

waste components for some waste

streams, and also confirmed that a QA

program had been established and

executed at LANL in conformance with

Nuclear Quality Assurance

requirements. Moreover, DOE

demonstrated that the WWIS is

functional with respect to LANL—i.e.,

that procedures are in place at LANL for

adding information to the WWIS

system, that information can be

transmitted from LANL and

incorporated into the central database,

and that data in the WWIS database can

be compiled to produce the types of

reports described in the CCA for

tracking compliance with the waste

limits. At the same time, DOE

demonstrated that the WWIS is

functional with respect to the WIPP

facility—i.e., that information

incorporated into the central database

can be retrieved at the WIPP and

compiled to produce reports for tracking

compliance with the waste limits.

Therefore, EPA finds DOE in

compliance with §§ 194.24(c)(4) and (5)

for legacy debris waste at LANL. (Docket

A–93–02, Items V–B–15 and V–B–2,

CARD 24) The EPA’s decision is limited

to the waste that can be characterized

using the systems and processes audited

by DOE, inspected by EPA, and found

to be adequately implemented at

LANL.33 The EPA does not find,

however, that DOE has demonstrated

compliance with § 194.24(c)(4) for any

other waste stream at LANL, or with

§§ 194.24(c)(4) and (5) at any other

waste generator site.

For any LANL waste streams using

other characterization processes or any

other waste generator site, before waste

can be shipped to the WIPP, EPA must

determine that the site has implemented

a system of controls at the site, in

accordance with § 194.24(c)(4), to

confirm that the total amount of each

waste component that will be emplaced

in the disposal system will not exceed

the upper limiting value or fall below

the lower limiting value described in

the introductory text of paragraph (c) of

§ 194.24. The implementation of such a

system of controls shall include a

demonstration that the site has

procedures in place for adding data to

the WWIS, and that such information

can be transmitted from that site to the

WWIS database; and a demonstration

that measurement techniques and

control methods can be implemented in

accordance with § 194.24(c)(4) for the
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27391

waste stream(s) proposed for disposal at

the WIPP. Condition 3 prohibits DOE

from shipping waste for disposal at

WIPP until EPA has approved sitespecific waste characterization programs

and controls. The system of controls

must also be implemented in

accordance with the QA requirements of

40 CFR 194; see Condition 2. (For

further information on EPA’s approval

process, see § 194.8, ‘‘Approval Process

for Waste Shipment from Waste

Generator Sites for Disposal at the

WIPP.’’)

Section 194.24(d) requires DOE either

to include a waste loading scheme

which conforms to the waste loading

conditions used in the PA and in

compliance assessments, or to assume

random placement of waste in the

disposal system. The DOE elected to

assume that radioactive waste would be

emplaced in the WIPP in a random

fashion. The DOE examined the possible

effects of waste loading configurations

on repository performance (specifically,

releases from human intrusion

scenarios) and concluded that the waste

loading scheme would not affect

releases. The DOE incorporated the

assumption of random waste loading in

its performance and compliance

assessments (pursuant to §§ 194.32 and

194.54, respectively).

The EPA determined that, because the

DOE had assumed random waste

loading, a final waste loading plan was

unnecessary. The EPA determined that,

in the PA, DOE accurately modeled

random placement of waste in the

disposal system. Since EPA concurred

with DOE that a final waste loading plan

was unnecessary, DOE does not have to

further comply with § 194.24(f),

requiring DOE to conform with the

waste loading conditions, if any, used in

the PA and compliance assessment.

Therefore, EPA finds that DOE complies

with §§ 194.24(d) and (f).

Section 194.24(e) prohibits DOE from

emplacing waste in the WIPP if its

disposal would cause the waste

component limits to be exceeded.

Section 194.24(g) requires DOE to

demonstrate that the total inventory

emplaced in the WIPP will not exceed

limitations on TRU waste described in

the WIPP LWA. Specifically, the WIPP

LWA defines limits for: surface dose

rate for remote-handled (‘‘RH’’) TRU

waste, total amount (in curies) of RH–

TRU waste, and total capacity (by

volume) of TRU waste to be disposed.

(WIPP LWA, Section (7)(a)) In order to

meet the §§ 194.24(e) and (g) limits,

DOE intends to rely on the TRU QAPP,

WAC, and a two-phase system of

controls for waste characterization—preshipment (at waste generator sites) and

pre-receipt (at the WIPP). The DOE

stated that the WWIS will be used to

track specific data related to each of the

WIPP LWA limits; by generating routine

WWIS reports, DOE will be able to

determine compliance with the imposed

limits. The WWIS will also be used to

track information on each of the

important waste components for which

limits were established. The EPA finds

that the WWIS is adequate to track

adherence to the limits, and that the

WWIS has been demonstrated to be

fully functional at the WIPP facility; as

discussed above, waste generator sites

will demonstrate WWIS procedures

before they can ship waste for disposal

at the WIPP. Therefore, EPA finds DOE

in compliance with §§ 194.24(e) and (g).

Section 194.24(h) allows EPA to

conduct inspections and record reviews

to verify compliance with the waste

characterization requirements. As

discussed above, EPA intends to

monitor execution of waste

characterization and QA programs at

waste generator sites through

inspections and record reviews.

In summary, EPA finds that DOE is in

compliance with § 194.24, and that

LANL has demonstrated compliance

with §§ 194.24(c)(3) through (5) for

legacy debris waste and may therefore

ship TRU waste for disposal at the WIPP

(as such shipments relate solely to

compliance with EPA’s disposal

regulations; other applicable

requirements or regulations still may

need to be fulfilled before disposal may

commence). The EPA’s final

determination of compliance is limited

to the EPA’s decision is limited to the

legacy debris waste that can be

characterized using the systems and

processes audited by DOE, inspected by

EPA, and found to be adequately

implemented at LANL. It is important to

note that EPA’s LANL approval does not

imply that DOE’s internal certification

processes can substitute for EPA’s

approval of waste generator sites or

processes used to characterize waste

stream(s)—including QA measures, use

of process knowledge, and the system of

controls (other than LANL’s legacy

debris waste approved in today’s

action). The EPA will inspect the

individual certification process for each

waste generator site and for one or more

waste stream(s). (For further information

on EPA’s approval process, see § 194.8,

‘‘Approval Process for Waste Shipment

from Waste Generator Sites for Disposal

at the WIPP.’’)

The DOE may not ship other waste

streams for emplacement at the WIPP

until EPA determines that (1) DOE has

provided adequate information on how

process knowledge will be incorporated

into waste characterization activities for

a particular waste stream (or group of

waste streams) at a generator site, and

(2) DOE has demonstrated that the

system of controls described in

§ 194.24(c)(4) and (5) has been

established for the site. In particular,

DOE must demonstrate that the WWIS

system is functional for any waste

generator site before waste may be

shipped, and that the system of controls

(including measurement techniques)

can be implemented for each waste

stream which DOE plans to dispose in

the WIPP. As discussed in the preamble

for § 194.22, DOE must also demonstrate

that sites have established and executed

the requisite QA programs described in

§§ 194.22(a)(2)(i) and 194.24(c)(3) and

(5).

The EPA received many public

comments on § 194.24. The majority of

the comments focused primarily on

whether or not DOE could adequately

characterize waste to be sent to the

WIPP. In response to such concerns,

EPA believes it is useful to explain and

clarify the general process of waste

characterization as required by § 194.24,

and to describe the activities EPA

expects to monitor for future waste

characterization. First, § 194.24(a)

requires DOE to describe the chemical,

radiological, and physical composition

of the wastes to be emplaced in the

WIPP. Second, DOE must conduct an

analysis that substantiates that: (1) all

characteristics of the wastes which may

influence containment in the repository

have been identified and assessed

(§ 194.24(b)(1)); (2) all components of

the wastes which influence such waste

characteristics have been identified and

assessed (§ 194.24(b)(2)); and (3) any

decision not to consider a waste

characteristic or component on the basis

that it will not significantly influence

containment of the waste.

(§ 194.24(b)(3)) Third, for each waste

component identified as being

significant, DOE is to specify a ‘‘limiting

value’’ of the total inventory of such

waste components to be emplaced in the

repository. (§ 194.24(c)) Fourth, DOE

must demonstrate that, for the total

inventory of waste proposed to be

emplaced in the disposal system, the

WIPP will comply with the numeric

requirements of §§ 194.34 and 194.55

for the upper and lower limiting values

of the identified waste components.

(§ 194.24(c)(1)) Fifth, DOE must identify

and describe the methods used to

quantify the limits of waste

components. (§ 194.24(c)(2))

At this point, § 194.24 imposes

requirements that shift the focus from

information on, and assessment of, the

total waste inventory to procedures for
27392 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

34AK is used by DOE to (1) delineate waste

streams to facilitate further characterization; (2)

identify radionuclide content as a basis for further

radioassay (‘‘NDA’’) determinations, and identify

the combustible and metal content to determine the

radionuclide content as a basis for radiography and/

or visual examination (‘‘NDE/VE’’); and (3) make

hazardous waste determinations for wastes

regulated under the Resource Conservation and

Recovery Act.

35All waste containers will undergo NDA

techniques to allow an item to be tested without

altering its physical or chemical form. NDA

techniques approved for use on WIPP containers

can be classified as active or passive. Passive NDA

methods measure spontaneously emitted radiations

produced through radioactive decay of isotopes

inside the waste containers. Active NDA methods

measure radiations produced by artificially

generated reactions in waste material.

36Results of head-space gas sampling and

chemical analyses are compared with acceptable

knowledge determinations to assess the accuracy of

acceptable knowledge. Additional analysis of headspace gas for volatile organic compounds, and

additional use of NDA, radiography, and other

characterization methods may be employed to

further characterize waste to meet regulations that

apply to the hazardous (but not necessarily

radioactive) portions of the WIPP waste. The

requirements for hazardous waste are enforced by

the State of New Mexico.

characterization of the waste at

individual waste generator sites and

accurate assessment of the waste

inventory. First, DOE must show that

the AK used to quantify the waste

components at the waste generator sites

will conform with QA requirements of

§ 194.22. Then, to ensure that the

generator sites ship only waste that

conforms with the waste component

limits, a system of controls must be

implemented that tracks and measures

the waste components destined for the

WIPP. This system of controls must also

comply with the QA requirements of

§ 194.22.

The approval process for site-specific

waste characterization controls and QA

programs includes a Federal Register

notice, public comment period, and onsite EPA audits or inspections to

evaluate implementation. (See

Condition 2, Condition 3, and § 194.8.)

Prior to an EPA audit or inspection, EPA

expects to receive certain documents

from DOE. To determine that the

procedures used to characterize waste

(e.g., measuring and testing, sample

control, equipment assessments) are

based on good technical practices, and

the personnel are qualified to perform

the task, EPA expects to receive the

following general documents which

conform with the requirements of

§ 194.22: Site-Specific Quality

Assurance Program Plan (‘‘QAPP’’) and

a report or reports from CAO’s QA

organization that verifies the

establishment and implementation of

the Nuclear Quality Assurance

requirements identified in § 194.22.

Likewise, DOE will provide technical

documents prior to an audit or

inspection to verify the methods for

characterizing, quantifying, and tracking

waste. Such technical documents will

include information on the use of both

process knowledge and measurement

methods for waste characterization.

First, for measurement equipment such

as NDA, NDE, and VE, DOE may

provide information on measuring and

testing, equipment assessments, sample

control, data documentation, and

software control. For AK, DOE may

provide the AK package which provides

information on the areas and buildings

from which the waste stream was

generated, the waste stream volume and

time period of generation, the waste

generating process described for each

building, the process flow diagrams, and

the material inputs or other information

that identifies the chemical and

radionuclide content of the waste

stream and the physical waste form. In

addition, the following supplemental

information may be provided for AK

records: process design documents,

standard operating procedures,

preliminary and final safety analysis

reports and technical safety

requirements, waste packaging logs, site

databases, information from site

personnel, standard industry

information, previous analytical data

relevant to the waste stream, material

safety data sheets or other packaging

information, sampling and analysis data

from comparable or surrogate waste

streams, and laboratory notebooks that

detail the research processes and raw

materials used in experiments.

The fundamental objective of EPA’s

review of DOE’s waste characterization

at waste generator sites is to ensure that

the proposed system of controls can

quantify and track both the

radionuclides and the four waste

component limits identified as

important for the repository

performance. Because DOE’s defense

missions varied at the sites, the waste

generated and the methods to

characterize waste vary accordingly.

These variations in practices and

methods result in the need to review

two general areas: (1) AK packages and

(2) the system of controls, including

measurement methods and tracking

procedures. Therefore, EPA finds that it

is important to clarify what is entailed

by both general areas.

Thirty-five percent of WIPP waste is

currently classified as ‘‘retrievably

stored waste,’’ which is TRU waste

generated after the 1970’s but before the

implementation of the TRU Waste

Characterization Quality Assurance

Program Plan (‘‘QAPP’’). Retrievably

stored waste containers will be

classified into waste streams using

acceptable knowledge.34 All retrievably

stored waste containers will be

examined using radiography or visual

examination to confirm the physical

waste form (or ‘‘Summary Category

Group’’), to verify the absence of

prohibited items, and to determine the

waste characterization techniques to be

used. To confirm the results of

radiography, a statistically selected

number of the Contact-Handled

Transuranic waste container population

will be visually examined by opening

the containers to inspect waste contents

to verify the radiography results. If

visual examination results for a drum

conflict with the results of radiography,

the drum and possibly the entire waste

stream is reclassified, and a higher

percentage of future drums will be

required to undergo visual examination.

Representativeness of containers

selected for visual examination will be

validated by reviewing documents that

show that true random samples were

collected. Repackaged retrievably stored

waste may be handled as newly

generated waste, with the Summary

Category Group confirmed by using

visual examination instead of

radiography. Retrievably stored waste

will be assayed using Non Destructive

Assay (‘‘NDA’’) 35, and will undergo

headspace-gas sampling and analysis for

volatile organic compound

concentrations.36

Sixty-five percent of all WIPP waste is

to-be-generated TRU waste. To-begenerated waste characterization will

begin with verification that processes

generating the waste have operated

within established written procedures.

Waste containers will be classified into

waste streams using acceptable

knowledge. Hazardous and radioactive

constituents in to-be-generated wastes

will be documented and verified at the

time of generation to provide acceptable

knowledge for the waste stream.

Verifying that the physical form of the

waste (Summary Category Group)

corresponds to the physical form of the

assigned waste stream is accomplished

by visual examination during packaging

of the waste into the drums. This

process consists of operator

confirmation that the waste is assigned

to a waste stream that has the correct

Summary Category Group for the waste

being packaged into the drums. If

confirmation cannot be made, corrective

actions will be taken. A second

operator, who is equally trained to the

requirements of the WAC and TRU

Waste Characterization QAPP, will

provide additional verification by

reviewing the contents of the waste
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27393

container to ensure correct reporting. If

the second operator cannot provide

concurrence, corrective actions will be

taken. To-be-generated waste will not

undergo radiography, as the waste will

be identified by visual examination

during packaging. All to-be-generated

waste containers will undergo

headspace-gas analysis for volatile

organic compound and their

concentrations, and NDA for

radioisotopes and their activities.

Acceptable knowledge, visual

examination during packing, NDA and

headspace-gas sampling and analysis

are used to further characterize

homogeneous solids, soils/gravel, and

debris waste. In addition, newly

generated streams of such wastes will be

randomly sampled a minimum of once

per year and analyzed for total volatile

and semi-volatile organic compounds

and metals.

A system of controls is used to

confirm that the total amount of each

waste component that will be emplaced

in the disposal system does not exceed

the upper limiting value or fall below

the lower limiting value for the

component. The system of controls for

WIPP waste has two phases for DOE’s

internal process. Phase I entails Waste

Stream Screening and Verification,

which will occur before waste is

shipped to the WIPP, and is a three-step

process. First, an initial audit of the site

will be conducted by DOE’s Carlsbad

Area Office as part its audit program

before the WIPP could begin the process

of accepting waste from a site. The audit

provides on-site verification of

characterization procedures, data

package preparation and recordkeeping.

Second, the generator site personnel

perform the waste characterization data

package completeness/accuracy review

and either accept or reject the data.

Third, if the data are accepted, the site

waste characterization data are

transferred manually or electronically

via the WWIS to the WIPP. At the WIPP,

screening includes verification that all

of the required elements of a waste

characterization data package are

present and that the data meet

acceptance criteria required for

compliance. Waste stream approval or

rejection to ship to the WIPP is the

outcome of Phase I.

Phase II includes examination of a

waste shipment after it has arrived at

the WIPP, and is a three-step process.

First, upon receipt of a waste shipment,

the WIPP personnel determine manifest

completeness and sign the manifest

before the driver may depart. Second,

WIPP personnel determine waste

shipment completeness by checking the

bar-coded identification number found

on each TRU waste container. The barcoded identification number is noted

and checked against the WWIS. The

WWIS maintains waste container

receipt and emplacement information.

Third, waste shipment irregularities or

discrepancies are identified and

resolved. If there are discrepancies, the

generator site is contacted for

resolution. Finally, WIPP personnel

compare the container identification

number with a list of those approved for

disposal at the WIPP. Waste shipment

approval or rejection for disposal at the

WIPP is the outcome of Phase II. (For

further information on the system of

controls, see Docket A–93–02, Item V–

B–2, CARD 24, Section 24.H.2.)

In summary, all waste sent to WIPP

will be appropriately and thoroughly

characterized. First, the acceptable

knowledge provides essential waste

content information that later

determines the waste categories. The AK

process undergoes quality assurance

checks to confirm good technical

practices and qualified personnel. Then,

the measurement techniques (NDA,

NDE, VE) confirm the AK data, and

further define the content and limits of

the waste. Further confirmation of the

accuracy of the waste characterization is

provided by the extensive tracking

system. Again, quality assurance checks

are applied to the tracking and

measurement controls. The waste

characterization process, if

implemented accordingly, provides

complete and thorough characterization

of the waste. The DOE has committed to

implement this process. No waste

generator site will be allowed to ship

proposed waste streams to the WIPP

until the waste characterization process

detailed above is met at that generator

site for the given waste stream(s).

3. Future State Assumptions (§ 194.25)

Section 194.25 stipulates that

performance assessments (‘‘PA’’) and

compliance assessments ‘‘shall assume

that characteristics of the future remain

what they are at the time the

compliance application is prepared,

provided that such characteristics are

not related to hydrogeologic, geologic or

climatic conditions.’’ Section 194.25

also requires DOE to provide

documentation of the effects of potential

changes of hydrogeologic, geological,

and climatic conditions on the disposal

system over the regulatory time frame.

The purpose of the future state

assumptions is to avoid unverifiable and

unbounded speculation about possible

future states of society, science,

languages, or other characteristics of

mankind. The Agency has found no

acceptable methodology that could

make predictions of the future state of

society, science, languages, or other

characteristics of mankind. However,

the Agency does believe that established

scientific methods can make plausible

predictions regarding the future state of

geologic, hydrogeologic, and climatic

conditions. Therefore, § 194.25 focuses

the PA and compliance assessments on

the more predictable significant features

of disposal system performance, instead

of allowing unbounded speculation on

all developments over the 10,000-year

regulatory time frame.

The EPA proposed to find DOE in

compliance with the requirements of

§ 194.25 because the future state

assumptions that DOE made and

documented in the CCA were inclusive

of all relevant elements of the PA and

compliance assessments and were

consistent with the requirements of

§ 194.25. (62 FR 58816–7) The Agency

reviewed the future state assumptions

DOE made about hydrogeologic and

geologic characteristics and found that

DOE accurately characterized, screened,

and modeled the potential changes from

current conditions. For climatic

changes, EPA found DOE’s approach to

be conservative and consistent with the

compliance criteria, since DOE

examined the worst-case scenario of

increased precipitation at the WIPP

rather than the potential effects of global

warming, which could be beneficial to

the WIPP. (§ 194.25(b)(3)) The EPA

found that DOE’s incorporation of these

changes into the PA was adequate.

Finally, EPA found that the CCA’s

approach to dealing with uncertainty,

including use of conservative

assumptions to compensate for

uncertainty, are consistent with the

features, events, and processes list,

screening arguments, and model

descriptions.

The EPA received no public

comments on this topic beyond those

addressed in the proposal, and so finds

DOE in compliance with the

requirements of § 194.25. For further

information concerning EPA’s

evaluation of compliance with § 194.25,

see CARD 25. (Docket A–93–02, Item V–

B–2) For additional information on the

features, events, and processes included

in the PA and compliance assessments,

see CARD 32 (Docket A–93–02, Item V–

B–2) and the preamble discussion of

performance assessment issues (Section

VIII.B). For additional information on

both geologic and hydrogeologic

conditions of the WIPP, see the

preamble discussion of § 194.14.

4. Expert Judgment (§ 194.26)

The requirements of 40 CFR 194.26

apply to expert judgment elicitation.
27394 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

Expert judgment is typically used to

elicit two types of information:

numerical values for parameters

(variables) that are measurable only by

experiments that cannot be conducted

due to limitations of time, money, and

physical situation; and essentially

unknowable information, such as which

features should be incorporated into

passive institutional controls to deter

human intrusion into the repository. (61

FR 5228) Quality assurance

requirements (specifically

§ 194.22(a)(2)(v)) must be applied to any

expert judgment to verify that the

procedures for conducting and

documenting the expert elicitation have

been followed.

The requirements of 40 CFR Part 194

prohibit expert judgment from being

used in place of experimental data,

unless DOE can justify that the

necessary experiments cannot be

conducted. Expert judgment may

substitute for experimental data only in

those instances in which limitations of

time, resources, or physical setting

preclude the successful or timely

collection of data.

The CCA did not identify any formal

expert elicitation activities. During the

Agency’s review of performance

assessment (‘‘PA’’) parameters, EPA

found inadequate explanation and

information for 149 parameters that

DOE claimed had been derived using

professional judgment. The compliance

criteria do not provide for utilization of

‘‘professional judgement.’’ Input

parameters are to be derived from data

collection, experimentation, or expert

elicitation. The EPA requested that DOE

provide additional information on the

derivation of the 149 parameters.

(Docket A–93–02, Items II–I–17, II–I–25,

and II–I–27)

The DOE responded to EPA’s requests

by adding information to and improving

the quality of the records stored in the

Sandia National Laboratory (‘‘SNL’’)

Records Center in order to enhance the

traceability of parameter values. The

EPA deemed the documentation

provided by DOE adequate to

demonstrate proper derivation of all but

one of the ‘‘professional judgment’’

parameters—the waste particle size

distribution parameter. For a

comprehensive discussion of the

technical review of PA parameters, see

the preamble discussion of performance

assessment, CARD 23 (Section 12.0),

and EPA’s ‘‘Parameter Report’’ and

‘‘Parameter Justification Report.’’

(Docket A–93–02, Items V–B–2, V–B–

12, V–B–14) The EPA required DOE to

use the process of expert elicitation to

develop the value for the waste particle

size distribution parameter. (Docket A–

93–02, Item II–I–27)

The waste particle size parameter is

important in performance assessments

because the distribution of waste

particle diameters affects the quantity of

radioactive materials released in

spallings from inadvertent human

intrusion. Because particle diameters

are uncertain and cannot be estimated

either directly from available data or

from data collection or experimentation,

the waste particle size parameter had to

be based on an elicitation of expert

judgment.

The DOE conducted the expert

judgment elicitation on May 5–9, 1997.

The results of the expert elicitation

consisted of a model for predicting

waste particle size distribution as a

function of the processes occurring

within the repository, as predicted by

the PA. The DOE completed a final

report entitled, ‘‘Expert Elicitation on

WIPP Waste Particle Size

Distributions(s) During the 10,000-Year

Regulatory Post-closure Period.’’

(Docket A–93–02, Item II–I–34) The

particle size distribution derived from

the expert elicitation was incorporated

in the PA verification test (‘‘PAVT’’)

calculations.

The EPA’s review of DOE’s

compliance with the requirements of

§ 194.26 principally focused on the

conduct of the elicitation process, since

§ 194.26 sets specific criteria for the

performance of an expert judgement

elicitation. The EPA observed DOE’s

elicitation process and conducted an

audit of the documentation prepared in

support of DOE’s compliance with

§ 194.26. The scope of the audit covered

all aspects of the expert judgment

elicitation process, including: panel

meetings, management and team

procedures, curricula vitae of panel

members, background documents, and

presentation materials. The EPA also

assessed compliance with the quality

assurance requirements of

§ 194.22(a)(2)(v). The EPA found that

the documentation was appropriate, that

the panel members were appropriately

qualified, and that the results of the

elicitation were used consistent with the

stated purpose; EPA, therefore,

proposed to find DOE in compliance

with § 194.26. (62 FR 58817–18)

Comments on EPA’s proposed

decision for § 194.26 related to two

main issues: (1) Commenters questioned

DOE’s statement that it did not conduct

any expert judgement activities in

developing the CCA; and (2)

commenters questioned the use or role

of ‘‘professional judgement’’ in the

development of input parameters used

in the CCA. The DOE’s understanding of

expert judgment was consistent with

EPA’s use of the term ‘‘expert

judgment’’ in the compliance criteria,

namely a formal, highly structured

elicitation of expert opinion. (Response

to Comments for 40 CFR Part 194,

Docket A–92–56, Item V–C–1, p. 8–4)

However, EPA agrees that the CCA

initially did not contain adequate

information to ascertain whether a large

number of the input parameters had

been properly derived. The DOE

subsequently provided additional

information, and substantially improved

the quality of the records at the SNL

Records Center, which enabled EPA to

confirm that all but one of the

parameters were adequately supported.

In regard to the use of professional

judgement in the development of input

parameters, the compliance criteria in

§ 194.26 do not provide for derivation of

input parameters through ‘‘professional

judgement.’’ Input parameters used in

the PA are to be derived from data

collection, experimentation, or expert

elicitation. The Agency, however,

recognizes that raw data resulting from

data collection or experimentation may

require ‘‘professional judgment’’ in the

development of input parameters.

Professional scientific judgment may be

used to interpolate, extrapolate,

interpret, and apply data to develop

parameter values but cannot substitute

for data. (Expert judgment may

substitute for data, but only when

information cannot reasonably be

obtained through data collection or

experimentation.) The applicability of

§ 194.26 does not extend to professional

scientific judgment used in such

circumstances. (Docket A–92–56, Item

V–C–1, p. 8–5)

Based on its review of documentation

developed by DOE and its contractors,

the results of EPA’s audit, and

consideration of public comments, EPA

concludes that DOE complied with the

requirements of § 194.26 in conducting

the required expert elicitation. For

further information on EPA’s evaluation

of compliance with § 194.26, see CARD

26. (Docket A–93–02, Item V–B–2)

5. Peer Review (§ 194.27)

Section 194.27 requires DOE to

conduct peer review evaluations related

to conceptual models, waste

characterization analyses, and a

comparative study of engineered

barriers. A peer review involves an

independent group of experts who are

convened to determine whether

technical work was performed

appropriately and in keeping with the

intended purpose. The required peer

reviews must be performed in

accordance with the Nuclear Regulatory
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27395

Commission’s NUREG–1297, ‘‘Peer

Review for High-Level Nuclear Waste

Repositories,’’ which establishes

guidelines for the conduct of a peer

review exercise. Section 194.27 also

requires DOE to document in the

compliance application any additional

peer reviews beyond those explicitly

required.

The EPA proposed to find DOE in

compliance with the requirements of

§ 194.27 because EPA’s independent

audit established that DOE had

conducted and documented the

required peer reviews in a manner

compatible with NUREG–1297. The

Agency also proposed that DOE

adequately documented additional peer

reviews in the CCA. The EPA received

no public comments on this topic

beyond those addressed in the proposal

(62 FR 58818), and so finds DOE in

compliance with the requirements of

§ 194.27. For further information

concerning EPA’s evaluation of

compliance with § 194.27, see CARD 27.

(Docket A–93–02, Item V–B–2)

D. Assurance Requirements

1. Active Institutional Controls

(§ 194.41)

Section 194.41 implements the active

institutional controls (‘‘AICs’’)

assurance requirement. The disposal

regulations define AICs as ‘‘controlling

access to a disposal site by any means

other than passive institutional controls,

performing maintenance operations or

remedial actions at a site, controlling or

cleaning up releases from a site, or

monitoring parameters related to

disposal system performance.’’ (40 CFR

191.12) Section 194.41 requires AICs to

be maintained for as long a period of

time as is practicable after disposal;

however, contributions from AICs for

reducing the rate of human intrusion in

the PA may not be considered for more

than 100 years after disposal.

The DOE proposed to: construct a

fence and roadway around the surface

footprint of the repository; post warning

signs; conduct routine patrols and

surveillance; and repair and/or replace

physical barriers as needed. The DOE

also identified other measures that

function as AICs, such as DOE’s

prevention of resource exploration at

the WIPP and DOE’s construction of

long-term site markers. The DOE will

maintain the proposed AICs for at least

100 years after closure of the WIPP, and

the WIPP PA assumed that AICs would

prevent human intrusion for that period.

The EPA reviewed the proposed AICs

in connection with the types of

activities that may be expected to occur

in the vicinity of the WIPP site during

the first 100 years after disposal (i.e.,

ranching, farming, hunting, scientific

activities, utilities and transportation,

ground water pumping, surface

excavation, potash exploration,

hydrocarbon exploration, construction,

and hostile or illegal activities) and

examined the assumptions made by

DOE to justify the assertion that AICs

will be completely effective for 100

years. The DOE stated in the CCA that

the proposed AICs will be maintained

for 100 years, and that regular

surveillance could be expected to detect

a drilling operation in a prohibited area

that is set up in defiance or ignorance

of posted warnings.

The EPA received public comments

on its proposed certification decision

stating that it was unreasonable to

assume that AICs could be completely

effective for 100 years. While EPA

recognizes that 100 percent

effectiveness of AICs over 100 years

cannot be established with certainty, the

proposed AICs are fully within DOE’s

present capability to implement and

may be expected to be enforceable for a

period of 100 years. Therefore, EPA

found it reasonable for DOE to assume

credit in the PA for 100 years. The EPA

found the assumptions regarding

longevity and efficacy of the proposed

AICs to be acceptable based on the fact

that the types of inadvertent intrusion

which AICs are designed to obviate are

not casual activities, but require

extensive resources, lengthy procedures

for obtaining legal permission, and

substantial time to set up at the site

before beginning.

Contributions from AICs in the PA are

considered as a reduction in the rate of

human intrusion. The EPA reviewed the

CCA and the parameter inputs to the PA

and determined that DOE did not

assume credit for the effectiveness of

active institutional controls for more

than 100 years after disposal. The EPA

found DOE’s assumptions to be

sufficient to justify DOE’s assertion that

AICs will completely prevent human

intrusion for 100 years after closure.

Because DOE adequately described the

proposed AICs and the basis for their

assumed effectiveness and did not

assume in the PA that AICs would be

effective for more than 100 years, EPA

finds DOE in compliance with § 194.41.

For further information on EPA’s

evaluation of compliance for § 194.41,

refer to CARD 41. (Docket A–93–02,

Item V–B–2)

2. Monitoring (§ 194.42)

Section 194.42 requires DOE to

monitor the disposal system to detect

deviations from expected performance.

The monitoring requirement

distinguishes between pre-and postclosure monitoring because the

monitoring techniques that may be used

to access the repository during

operations (pre-closure) and after the

repository has been backfilled and

sealed (post-closure) are different.

Monitoring is intended to provide

information about the repository that

may affect the predictions made about

the PA or containment of waste. The

EPA proposed that DOE was in

compliance with this requirement. (62

FR 58827)

Public comments on EPA’s proposed

decision stated that the monitoring plan

presented by DOE does not comply with

certain hazardous waste (Resource

Conservation and Recovery Act) and

Nuclear Regulatory Commission

(‘‘NRC’’) requirements. However, the

monitoring techniques and parameters

suggested by commenters are not

required by § 194.42, which requires

only that the post-closure monitoring

plan be complementary to certain

applicable hazardous waste monitoring

requirements. The purpose of this

language is to eliminate potential

overlap with hazardous waste

monitoring requirements while ensuring

that monitoring will be conducted even

if not required by the applicable

hazardous waste regulations. (Response

to Comments for 40 CFR Part 194,

Docket A–92–56, Item V–C–1, p. 14–7)

One commenter stated that DOE

should monitor additional parameters

and perform remote monitoring to

prolong the length of time that data is

gathered. The EPA determined that

monitoring the additional parameters

would provide no significant benefit

because these parameters were not

identified as significant to the

containment of waste or to verifying

predictions made about the repository.

The EPA also determined that

additional remote monitoring of the

panel rooms would neither provide

significant information on the

performance of the repository nor verify

predictions about its performance.

The plans in the CCA addressed both

pre-closure and post-closure monitoring

and included the information required

by the compliance criteria. Therefore,

EPA finds that DOE is in compliance

with the requirements of § 194.42.

Under its authority at § 194.21, EPA

intends to conduct inspections of DOE’s

implementation of the monitoring plans

that DOE has set forth. For further

information on EPA’s evaluation of

compliance for § 194.42, see CARD 42.

(Docket A–93–02, Item V–B–2)
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3. Passive Institutional Controls

(§ 194.43)

The compliance criteria at § 194.43

require a description of passive

institutional controls (‘‘PICs’’) that will

be implemented at the WIPP. The EPA

defined PICs in the disposal regulations

as markers, public records and archives,

government ownership of and

restrictions on land use at a site, and

any other means of preserving

knowledge of a site. (40 CFR 191.12)

PICs are intended to deter unintentional

intrusions into a disposal system by

people who otherwise might not be

aware of the presence of radioactive

waste at the site.

Section 194.43 requires DOE to: (1)

identify the controlled area with

markers designed, fabricated, and

emplaced to be as permanent as

practicable; (2) place records in local

State, Federal, and international

archives and land record systems likely

to be consulted by individuals in search

of resources; and (3) employ other PICs

intended to indicate the location and

dangers of the waste. In accordance with

§ 194.43(b), DOE also must indicate the

period of time that PICs are expected to

endure and be understood by potential

intruders. Finally, DOE is permitted to

propose a credit for PICs in the PA, as

explained in § 194.43(c). This credit

must be based on the proposed

effectiveness of PICs over time, and

would take the form of reduced

likelihood in the PA of human intrusion

over several hundred years. The

compliance criteria prohibit DOE from

assuming that PICs could entirely

eliminate the likelihood of future

human intrusion into the WIPP.

The EPA proposed that DOE complied

with § 194.43(a) and (b) because the

measures proposed in the CCA are

comprehensive, practicable, and likely

to endure and be understood for long

periods of time. The EPA also proposed

a condition that DOE submit additional

information concerning the schedule for

completing PICs, the fabrication of

granite markers, and commitments by

various recipients to accept WIPP

records. (62 FR 58827–29) The EPA did

not receive any comments disputing this

decision, and so finds DOE in

compliance with § 194.43(a) and (b).

However, DOE must fulfill Condition 4

of Appendix A to 40 CFR Part 194 no

later than the final recertification

application. For further information on

EPA’s evaluation of compliance with

§ 194.43, see CARD 43. (Docket A–93–

02, Item V–B–2)

Some commenters expressed the

concern that PICs in general, and DOE’s

plan in particular, would not be

sufficient to prevent drilling or other

intrusions into the WIPP over 10,000

years. The EPA has never asserted that

PICs, as an assurance measure, could or

must be sufficient to prevent human

intrusion into a site entirely or for a

specified period (such as 10,000 years).

In fact, the WIPP compliance criteria

prohibit DOE from assuming that PICs

can completely eliminate the likelihood

of human intrusion. (§ 194.43(c)) DOE’s

design incorporates features that will

serve to promote the endurance and

comprehensibility of PICs over time,

such as: redundant markers, highly

durable materials with low intrinsic

value, messages in multiple languages,

and record storage in multiple locations.

Also, the CCA clearly discusses the

manner in which DOE accounted in the

design for possible, realistic failures.

The Agency believes that the existence

of site-specific markers and records,

designed to be durable over long periods

of time, will greatly improve the

chances that future generations will

retain knowledge of the hazard posed by

waste stored at the WIPP.

The EPA proposed to deny DOE’s

request under § 194.43(c) that the

likelihood of human intrusion into the

WIPP during the first 700 years after

closure be reduced by 99 percent based

on the anticipated effectiveness of PICs.

The EPA denied the credit because DOE

did not use an expert judgment

elicitation to derive the credit, as

explicitly envisioned by the Agency.

The EPA expected that an expert

judgment elicitation that makes use of

the best available information and

expertise would be used to account for

the considerable uncertainties

associated with a prediction of the

ability of PICs to prevent human

intrusion hundreds of years into the

future. Since the WIPP is located in an

area of resource exploitation, the

uncertainty was not sufficiently

reflected in the near 100 percent credit

proposed in the CCA.

The Agency received comments both

supporting and refuting this decision.

Comments supporting EPA’s proposed

decision tended to reflect the position

that any PICs credit would be too

uncertain for use in the PA. In

opposition to EPA’s decision, comments

stated that EPA drew improper

conclusions about DOE’s use of expert

judgment and treatment of uncertainty.

These comments requested that EPA

reverse its denial of PICs credit, or at

least consider future credit proposals,

but did not identify why EPA’s

conclusions were incorrect other than to

reiterate positions taken in the CCA that

were explicitly assessed by EPA in the

proposal. (62 FR 58828) Therefore, EPA

sees no cause to reverse its decision to

deny DOE’s request for PICs credit

under § 194.43(c). However, EPA’s final

decision today applies only to the credit

proposal in the CCA and should not be

interpreted as a judgment on the use of

PICs credit in performance assessments

generally. In the future, DOE may

present to EPA additional information

derived from an expert elicitation of

PICs credit. Any future PICs credit

proposals will be considered in the

context of a modification rulemaking,

and will be subject to public

examination and comment.

4. Engineered Barriers (§ 194.44)

Section 194.44 requires DOE to

conduct a study of available options for

engineered barriers at the WIPP and

submit this study and evidence of its

use with the compliance application.

Consistent with the assurance

requirement found at 40 CFR 191.14,

DOE must analyze the performance of

the complete disposal system, and any

engineered barrier(s) that DOE

ultimately implements at the WIPP must

be considered in the PA and EPA’s

subsequent evaluation. Based on the

comparative study that constitutes

Appendix EBS of the CCA, DOE

proposed magnesium oxide (MgO)

backfill as an engineered barrier and

proposed to emplace bags of MgO

between and around waste containers in

the repository. The EPA proposed to

find DOE in compliance with § 194.44

because DOE conducted and

documented the required study in a

manner consistent with the WIPP

compliance criteria and proposed to

implement an engineered barrier to

delay the movement of water or

radionuclides. (62 FR 58829)

Public comments on the proposal

stated that the waste should be treated

before being placed in the repository.

Commenters stated that treatment of

waste could serve to provide additional

confidence in the safety of the disposal

system beyond that demonstrated by the

performance assessment, based on the

assumption that waste treatment would

reduce the potential effects of a

repository breach. Commenters

therefore urged EPA to encourage DOE

to treat the waste in order to add

additional assurance in the predicted

performance of the WIPP.

Section 194.44 of the compliance

criteria requires DOE to perform a

comparison of the benefits and

detriments of waste treatment options

(referred to as ‘‘engineered barriers’’ by

EPA and as ‘‘engineered alternatives’’ by

DOE). DOE’s evaluation incorporated

such treatment methods as vitrification

and shredding. Based on this
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27397

evaluation, DOE selected the use of

MgO as an engineered barrier. The EPA

determined that MgO will be an

effective barrier, based on DOE’s

scientific evaluation of the proposed

barrier’s ability to prevent or

substantially delay the movement of

radionuclides toward the accessible

environment.

Section 194.44 does not require

specific engineered barriers or the

implementation of more than one

engineered barrier. Since DOE will

employ the use of a barrier as required

by this section, and since the

performance assessment results showed

compliance with the containment

requirements with the use of this

barrier, EPA does not consider it

necessary to require DOE to treat waste

prior to emplacement. However, EPA

agrees that waste treatment or additional

barriers may further enhance the

containment ability of the WIPP. In the

future, if DOE were to select a new

treatment option (such as vitrification)

that differs significantly from the option

in the most recent compliance

application, DOE must inform EPA prior

to making such a change.

(§ 194.4(b)(3)(i) and (vi)) The EPA will

evaluate the information provided by

DOE and determine if the certification

warrants modification.

Other commenters expressed concern

that DOE failed to consider alternatives

to the proposed 55-gallon steel waste

drums that could reduce releases or the

formation of gas in the repository due to

the degradation of carbon. Commenters

further stated that DOE failed to

consider adequately how engineered

barriers could reduce releases from four

human intrusion scenarios: fluid

injection, air drilling, stuck pipe, and

direct brine release.

The EPA recognized that gas

production from waste drum

degradation was a relevant issue and so

included consideration of ‘‘improved

waste containers’’ in the list of factors

for DOE to consider when evaluating

engineered barriers. (40 CFR 194.44(b))

The DOE did, in fact, consider various

aspects of waste packages in the

engineered barrier study. Appendix A of

Appendix EBS (p. A–10) states that the

‘‘improved waste container’’ options

scored low in a qualitative assessment

because of their minimal ability to

improve conditions with respect to

waste solubility and shear strength. As

explained in CARD 44 (Docket A–93–

02, Item V–B–2), DOE also examined the

effects of engineered barriers on the

long-term performance of the WIPP

using the Design Analysis Model

(‘‘DAM’’), which provided a relative

comparison of the potential benefits of

the different barriers on the performance

of the repository. There was no attempt

to determine the absolute effect of the

barriers on the performance of the

repository since the objective of the

study (in accordance with the WIPP

compliance criteria) was only to provide

DOE with information for use in the

selection or rejection of additional

engineered barriers. (Docket A–93–02,

Item V–B–2, CARD 44, Section 44.C.4)

It was not necessary for DOE to show

the absolute effect of each barrier on the

WIPP’s performance in the face of a

specific human intrusion scenario such

as air drilling. Rather, it was sufficient

for DOE to consider the relative ability

of barriers to prevent or delay

radionuclide migration in the event of

human intrusion.

Other comments expressed concern

that the ‘‘containment’’ and ‘‘assurance’’

requirements were not kept separate, as

was intended by EPA’s disposal

standards. The separation of the

requirements is valid only to the extent

that engineered barriers may be used to

meet the containment requirements, but

must be used to meet the assurance

requirements. The effects of all

engineered barriers employed at the

WIPP must be considered in

performance assessments. Excluding

such barriers from consideration would

result in inaccurate modeling of the

disposal system, which is defined in

§ 191.12(a) to include engineered

barriers. (Response to Comments for 40

CFR Part 194, Docket A–92–56, Item V–

C–1, pp. 16–10, 16–13) Although not

required to comply with § 194.44, DOE

and others performed calculations

showing that the WIPP can comply with

the containment requirements with or

without the use of MgO as an

engineered barrier. (Docket A–93–02,

Items IV–D–12 and IV–G–7)

The EPA finds that DOE complies

with § 194.44. The EPA found that DOE

conducted the requisite analysis of

engineered barriers and selected an

engineered barrier designed to prevent

or substantially delay the movement of

water or radionuclides toward the

accessible environment. The DOE

provided sufficient documentation to

show that MgO can effectively reduce

actinide solubility in the disposal

system. The DOE proposed to emplace

a large amount of MgO around waste

drums in order to provide an additional

factor of safety and thus account for

uncertainties in the geochemical

conditions that would affect CO2

generation and MgO reactions. For

further information on EPA’s evaluation

of compliance for § 194.44, see CARD

44. (Docket A–93–02, Item V–B–2) For

further information regarding the PA

modeling of solubility and chemical

conditions in the repository, see CARD

23—Models and Computer Codes.

(Docket A–93–02, Item V–B–2)

5. Consideration of the Presence of

Resources (§ 194.45)

Section 194.45 implements the

assurance requirement that the disposal

system be sited so that the benefits of

the natural barriers of the disposal

system will compensate for any

increased probability of disruptions to

the disposal system resulting from

exploration and development of existing

resources. (61 FR 5232) In issuing the

WIPP compliance criteria, EPA

determined that the performance

assessment (‘‘PA’’) is the appropriate

tool to weigh the advantages and

disadvantages of the WIPP site because

the PA demonstrates whether potential

human intrusion will cause

unacceptably high releases of

radioactive material from the disposal

system. Comments on § 194.45 for the

proposed certification decision did not

address the question of compliance with

this requirement but instead focused on

the criterion itself, stating that it was

inconsistent with the original basis for

the assurance requirements to be

qualitative in nature. The EPA believes

that the presence of resources

requirement is reasonable because the

performance assessment must account

for the increased potential for human

intrusion into the disposal system due

to the presence of known resources,

based on historical rates of drilling and

mining in the vicinity of the WIPP.

(Docket A–92–56, Item V–C–1, p. 17–1)

In any case, it is beyond the scope of the

certification rulemaking to

fundamentally re-examine or change the

disposal regulations or compliance

criteria as they relate to the presence of

resources.

Because the PA incorporated human

intrusion scenarios and met EPA’s

release limits in accordance with the

WIPP compliance criteria, EPA

determines that DOE has demonstrated

compliance with § 194.45. For

discussion of comments on human

intrusion scenarios, results, and other

aspects of the PA, refer to Section B

(‘‘Performance Assessment: Modeling

and Containment Requirements’’) of this

preamble. For further information on

EPA’s evaluation of compliance for

§ 194.45, refer to CARD 45. (Docket A–

93–02, Item V–B–2)

6. Removal of Waste (§ 194.46)

Section 194.46 requires DOE to

provide documentation that the removal

of waste from the disposal system is

feasible for a reasonable period of time
27398 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

after disposal. In the proposed

certification decision on WIPP, EPA

proposed that DOE was in compliance

with this requirement.

Public comments on EPA’s proposed

decision expressed concern that there

would be no way to remove the waste

once the WIPP repository is sealed. The

technology used to dispose of the waste

is substantially the same as the

technology that would be used to

remove it. This technology may

reasonably be expected to remain

available for at least 100 years after the

repository is sealed. Public comments

also stated that EPA and DOE should

identify the limitations of DOE’s

removal of waste plan. In Appendix

WRAC of the CCA, DOE acknowledges

the expense and hazard of removing the

waste from the repository. The purpose

of the requirement at § 194.46 is to

demonstrate that the removal of waste

remains possible, not necessarily simply

or inexpensive, for a reasonable period

of time after disposal. (50 FR 38082)

The DOE demonstrated that it is

possible to remove waste from the

repository for a reasonable period of

time after disposal. Therefore, EPA

determines that DOE is in compliance

with § 194.46. For further information

on EPA’s evaluation of compliance with

§ 194.46, see CARD 46. (Docket A–93–

02, Item V–B–2)

E. Individual and Ground-water

Protection Requirements (§§ 194.51–55)

Sections 194.51 through 194.55 of the

compliance criteria implement the

individual protection requirements of

40 CFR 191.15 and the ground-water

protection requirements of Subpart C of

40 CFR Part 191. Assessment of the

likelihood that the WIPP will meet the

individual dose limits and radionuclide

concentration limits for ground water is

conducted through a process known as

compliance assessment. Compliance

assessment uses methods similar to

those of the PA (for the containment

requirements) but is required to address

only undisturbed performance of the

disposal system. That is, compliance

assessment does not include human

intrusion scenarios (i.e., drilling or

mining for resources). Compliance

assessment can be considered a

‘‘subset’’ of performance assessment,

since it considers only natural

(undisturbed) conditions and past or

near-future human activities (such as

existing boreholes), but does not include

the long-term future human activities

that are addressed in the PA.

Section 194.51 requires DOE to

assume in compliance assessments that

an individual resides at the point on the

surface where the dose from

radionuclide releases from the WIPP

would be greatest. The EPA required

that the CCA identify the maximum

annual committed effective dose and the

location where it occurs, and explain

how DOE arrived at those results.

In DOE’s analysis, an individual

receives the highest dose if one assumes

that the individual takes drinking water

directly from the Salado Formation at

the subsurface boundary of the WIPP

area. The DOE assumed that an

individual would receive the maximum

estimated dose regardless of location on

the surface and calculated the resultant

doses accordingly. EPA found this

approach to be conservative and

proposed that DOE complied with

§ 194.51. The Agency received no public

comments on this topic beyond those

addressed in the proposal (62 FR

58831), and so finds DOE in compliance

with the requirements of § 194.51.

Section 194.52 requires DOE to

consider in compliance assessments all

potential exposure pathways for

radioactive contaminants from the

WIPP. The DOE must assume that an

individual consumes two liters per day

of drinking water from any underground

source of drinking water outside the

WIPP area.

The DOE considered the following

pathways: an individual draws drinking

water directly from the Salado

Formation; an individual ingests plants

irrigated with contaminated water or

milk and beef from cattle whose stock

pond contained contaminated water

from the Salado; and an individual

inhales dust from soil irrigated with

contaminated water from the Salado.

Intended to result in the maximum

dose, DOE’s assumption that water is

ingested directly from the Salado

actually is so conservative as to be

unrealistic, since Salado water is highly

saline and would have to be greatly

diluted in order to function as drinking

or irrigation water.

The EPA proposed that DOE complied

with § 194.52 because DOE considered

all potential exposure pathways and

assumed that an individual consumes

two liters of Salado water a day,

following dilution. The Agency received

no public comments on this topic

beyond those addressed in the proposal

(62 FR 58831), and so finds DOE in

compliance with the requirements of

§ 194.52. For further information

concerning EPA’s evaluation of

compliance for §§ 194.51 and 194.52,

see CARD 51/52. (Docket A–93–02, Item

V–B–2)

Section 194.53 requires DOE to

consider in compliance assessments

underground sources of drinking water

(‘‘USDWs’’) near the WIPP and their

interconnections. A USDW is defined at

40 CFR 191.22 as ‘‘an aquifer or its

portion that supplies a public water

system, or contains a sufficient quantity

of ground water to do so and (i)

currently supplies drinking water for

human consumption or (ii) contains

fewer than 10,000 mg per liter of total

dissolved solids.’’

The DOE identified three potential

USDWs near the WIPP—the Culebra

Member of the Rustler Formation, the

Dewey Lake Red Beds, and the Santa

Rosa Sandstone of the Dockum Group—

despite incomplete data showing that

they meet the regulatory definition of a

USDW. The DOE did not analyze

underground interconnections among

these water bodies, instead assuming

conservatively that people would draw

water directly from the Salado

Formation, bypassing other USDWs

closer to the surface and thus resulting

in greater exposure.

The EPA proposed that DOE complied

with § 194.53 because DOE adequately

considered potential USDWs near the

WIPP. The Agency received a few

public comments that raised questions

about DOE’s approach to evaluating

USDWs. For example, some commenters

questioned DOE’s assertion that USDWs

such as Laguna Grande de la Sal would

not be contaminated if the WIPP is left

undisturbed. In fact, the compliance

assessments assumed that water in the

Salado Formation constituted a

hypothetical USDW that would provide

drinking water after being diluted.

Radionuclide concentrations would be

expected to be greatest in the Salado at

the subsurface boundary of the WIPP,

since the disposal system is located in

that geologic formation. Thus, by

demonstrating that EPA’s drinking

water standards would be met where

radioactive contamination would be

greatest, DOE also showed that other,

more distant potential aquifers also

would comply. This conservative

approach compensates for substantial

uncertainties that would otherwise be

involved in the calculation of

radionuclide transport to potential

USDWs.

Even using an analysis that was

designed to maximize radionuclide

releases, DOE showed that the WIPP

will comply with EPA’s limits for

radionuclides in ground water by a wide

margin. The EPA therefore finds DOE in

compliance with § 194.53. For further

information concerning EPA’s

evaluation of compliance with § 194.53,

see CARD 53. (Docket A–93–02, Item V–

B–2)

Sections 194.54 and 194.55 relate to

the scope and results of compliance

assessments conducted to determine
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27399

37Pub. L. 102–579, sections 4(b)(5) and 7(b)(2).

compliance with the individual dose

and ground-water protection

requirements. The EPA found that DOE

appropriately evaluated and screened

out natural features, processes, and

events related to undisturbed

performance, and proposed to find DOE

in compliance with § 194.54. (62 FR

58832) The Agency received no specific

comments on this decision. Comments

on issues that could affect predictions of

undisturbed performance, such as site

characterization or ground-water

modeling, are discussed separately in

this preamble and did not necessitate

changes to compliance assessments.

(See ‘‘Geologic Scenarios and Disposal

System Characteristics’’ under the

Performance Assessment sections of this

preamble.) The EPA therefore finds that

DOE complies with § 194.54. For further

information on EPA’s evaluation of

compliance with § 194.54, see CARD 54.

(Docket A–93–02, Item V–B–2)

The EPA found that compliance

assessments conducted by DOE

appropriately documented uncertainty,

documented probability distributions

for uncertain parameters, randomly

sampled across the distributions, and

generated and displayed a sufficient

number of estimates of radiation doses

and ground-water concentrations.

Further, the resulting estimates of

radiation doses and radionuclide

concentrations in ground water (and

independent calculations by EPA) were

well below the limits in § 191.15 and

Subpart C of 40 CFR Part 191. In its

proposal, the Agency found that DOE is

in compliance with the requirements of

§ 194.55, and received no comments

disputing this decision, which is

therefore finalized. For further

information on EPA’s evaluation of

compliance for § 194.55, see CARD 55.

(Docket A–93–02, Item V–B–2)

IX. Does DOE Need to Buy Existing Oil

and Gas Leases Near the WIPP?

The EPA finds that DOE does not

need to acquire existing oil and gas

leases in the vicinity of the WIPP in

order to comply with EPA’s disposal

regulations. These existing leases, and

EPA’s need to evaluate their effects on

the WIPP, are addressed by the 1992

WIPP Land Withdrawal Act (‘‘LWA’’)

which provides for EPA’s regulatory

authority at the WIPP.37 (See Section X

of this preamble, entitled ‘‘Why and

How Does EPA Regulate the WIPP,’’ for

more information on the WIPP LWA.)

The 1992 WIPP LWA withdrew the

geographic area containing the WIPP

facility from all forms of entry,

appropriation, and disposal under

public land laws. The WIPP LWA

transferred jurisdiction of the land to

the Secretary of Energy explicitly for the

use of constructing, operating, and

conducting other authorized activities

related to the WIPP. The WIPP LWA

prohibits all surface or subsurface

mining or oil or gas production is

prohibited at all times on or under the

land withdrawal area. (WIPP LWA,

section 4(b)(5)(A)) However, section

4(b)(5)(B) states that existing rights

under two oil and gas leases (Numbers

NMNM 02953 and 02953C) (referred to

as ‘‘the section 4(b)(5)(B) leases’’) shall

not be affected unless the Administrator

determines, after consultation with DOE

and the Department of the Interior, that

the acquisition of such leases by DOE is

required to comply with EPA’s final

disposal regulations.

Before DOE can emplace waste in the

WIPP, DOE must acquire the leases,

unless EPA determines that such

acquisition is not required. (WIPP LWA,

section 7(b)(2)) This determination is

separate and apart from the WIPP LWA

requirement for EPA to conduct the

certification decision by notice-andcomment rulemaking. (WIPP LWA,

section 8(d)). Nonetheless, the Agency

chose to address this matter as part of

the certification process because the

determination of whether potential

drilling on the leases could possibly

affect the integrity of the WIPP is closely

related to similar determinations that

must be made to determine compliance

with the disposal regulations and WIPP

compliance criteria. (See §§ 194.32(c),

194.54(b))

As discussed in the proposed

certification decision, EPA examined

DOE’s analysis of a number of potential

activities in the life cycle of a welldrilling, fluid injection (for both

waterflooding and brine disposal), and

abandonment—that could affect the

WIPP disposal system. The Agency

agreed with DOE that the effects of

drilling a borehole would be highly

localized, due to well casing procedures

and borehole plugging practices. The

EPA found that the effects of fluid

injection can also be expected to be

localized, due to underground injection

control requirements. Finally, even

abandoned boreholes would have little

consequence on waste panels more than

a meter away. Because the closest

possible approach of a borehole drilled

from the section 4(b)(5)(B) leases is over

2400 meters (8000 feet) from the WIPP

waste disposal rooms, EPA determined

that such a borehole would have an

insignificant effect on releases from the

disposal system (and in turn, on

compliance with the disposal

regulations). (62 FR 58835–58836)

For the reasons discussed above, EPA

concluded in its proposed rule that the

Secretary of Energy does not need to

acquire Federal Oil and Gas Leases No.

NMNM 02953 and No. NMNM 02953C.

(62 FR 58836) A number of comments

on the proposed rule suggested that

DOE conducted inadequate performance

assessment analyses on drilling

activities occurring prior to or soon after

disposal in the vicinity of the WIPP, but

only one commenter took issue directly

with EPA’s decision to not require the

Secretary of Energy to acquire the

Section 4(b)(5)(B) leases. This

commenter questioned the impact of

drilling activities by lease holders.

The DOE’s analysis of drilling for the

performance assessment indicated that

wells drilled into the controlled area,

but away from the waste disposal room

and panels, will not adversely affect the

disposal system’s capability to contain

radionuclides. A slant-drilled borehole

from outside the Land Withdrawal Area,

into the section 4(b)(5)(B) lease area at

least 6000 feet below the surface, would

be at least 2400 meters (8000) feet away

from the WIPP disposal rooms and

would thus have an insignificant effect

on releases from the disposal system or

compliance with the disposal

regulations. The EPA finds that

potential activities at the section

4(b)(5)(B) leases will not cause the WIPP

to violate the disposal regulations. (For

more information on drilling scenarios,

see the preamble discussions related to

performance assessment.) Therefore,

EPA determines that it is not necessary

for the Secretary of Energy to acquire

the Federal Oil and Gas Leases No.

NMNM 02953 and No. NMNM 02953C.

X. Why and How Does EPA Regulate

the WIPP?

The WIPP Land Withdrawal Act is the

statute that provides EPA the authority

to regulate the WIPP. The EPA’s

obligations and the limitations on EPA’s

regulatory authority under that law are

discussed below.

A. The WIPP Land Withdrawal Act

The EPA’s oversight of the WIPP

facility is governed by the WIPP Land

Withdrawal Act (‘‘LWA’’), passed

initially by Congress in 1992 and

amended in 1996. (Prior to the passage

of the WIPP LWA in 1992, DOE was

self-regulating with respect to the WIPP;

that is, DOE was responsible for

determining whether its own facility

complies with applicable regulations for

radioactive waste disposal.) The WIPP

LWA delegates to EPA three main tasks,

to be completed sequentially, for

reaching a compliance certification

decision. First, EPA must finalize
27400 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

38WIPP LWA, section 8(b).

39 50 FR 38066–38089 (September 19, 1985) and

58 FR 66398–66416 (December 20, 1993).

40 61 FR 5224–5245 (February 9, 1996).

41WIPP LWA, section 8(d).

42WIPP LWA, section 8(f). 43WIPP LWA, sections 7(b)(3) and 9.

general regulations which apply to all

sites—except Yucca Mountain—for the

disposal of highly radioactive waste.38

These regulations, located at Subparts B

and C of 40 CFR Part 191 (‘‘disposal

regulations’’), were published in the

Federal Register in 1985 and 1993.39

Second, EPA must develop, by

rulemaking, criteria to implement and

interpret the general radioactive waste

disposal regulations specifically for the

WIPP. The EPA issued the WIPP

compliance criteria, which are found at

40 CFR Part 194, in 1996.40

Third, EPA must review the

information submitted by DOE and

publish a certification decision.41

Today’s action constitutes EPA’s

certification decision as required by

section 8 of the WIPP LWA.

Today’s action also addresses the

requirement at section 7(b)(2) that,

before DOE can emplace waste in the

WIPP, DOE must acquire existing oil

and gas leases near the WIPP unless

EPA determines that such acquisition is

not required in order for DOE to comply

with the disposal regulations. The EPA

determines that acquisition of the leases

is not necessary. For further discussion

of this requirement, refer to the

preamble section entitled, ‘‘Does DOE

need to buy existing oil and gas leases

near the WIPP?’’

Besides requiring EPA to issue a

certification decision, the WIPP LWA

also requires the Agency to conduct

periodic recertifications, if the facility is

initially certified. Every five years, EPA

must determine whether documentation

submitted by DOE demonstrates that the

WIPP continues to be in compliance

with the disposal regulations.42

Recertifications are not conducted

through rulemaking, and are not

addressed by today’s action. However,

the WIPP compliance criteria address

the process by which EPA intends to

conduct recertifications, including

publishing public notices in the Federal

Register and providing a public

comment period. (§ 194.64) For further

information on recertification, refer to

the preamble sections entitled, ‘‘EPA’s

Future Role at the WIPP’’ and ‘‘How

will the public be involved in EPA’s

future WIPP activities?’’

B. Limits of EPA’s Regulatory Authority

at the WIPP

As discussed above, the WIPP LWA

conveys specific responsibilities on EPA

to ensure the safety of the WIPP as a

permanent disposal facility. The

Agency’s primary responsibility,

described in section 8 of the WIPP

LWA, is to determine whether the WIPP

facility will comply with EPA’s disposal

regulations. Members of the public have

expressed, in written comments and in

oral testimony on the proposed rule, a

desire for the Agency to oversee other

aspects of the WIPP’s operation. In

response to such concerns, EPA must

clarify that its authority to regulate DOE

and the WIPP is limited by the WIPP

LWA and other statutes which delineate

EPA’s authority to regulate radioactive

materials in general. The limitations on

EPA’s authority necessarily limit the

scope of the present rulemaking.

A number of commenters suggested

that EPA should explore alternative

methods of waste disposal, such as

neutralizing radioactive elements,

before proceeding with a certification

decision. Others stated that the WIPP

should be opened immediately because

underground burial of radioactive waste

is less hazardous than the current

strategy of above-ground storage. In the

WIPP LWA, Congress did not delegate

to EPA the authority to abandon or

delay the WIPP because future

technologies might evolve and eliminate

the need for the WIPP. Also, Congress

did not delegate to EPA the authority to

weigh the competing risks of leaving

radioactive waste stored above ground

compared to disposal of waste in an

underground repository. These

considerations are outside the authority

of EPA as established in the WIPP LWA,

and thus outside the scope of this

rulemaking. However, as technologies

evolve over the operating period of the

WIPP, DOE may incorporate them into

the facility design through a

modification or during the required

recertification process. The EPA will

evaluate how any such changes in

design or activities at the WIPP may

affect compliance with the radioactive

waste disposal regulations.

Some commenters requested that EPA

consider certain factors in making its

certification decision. These factors

include reviews by organizations other

than EPA, and the political or economic

motivations of interested parties. The

EPA’s certification decision must be

made by comparing the scope and

quality of relevant information to the

objective criteria of 40 CFR Part 194.

Where relevant, the Agency has

considered public comments which

support or refute technical positions

taken by DOE. Emotional pleas and

comments on the motives of interested

parties are factors that are not relevant

to a determination of whether DOE has

demonstrated compliance with the

disposal regulations and WIPP

compliance criteria, and are therefore

outside the scope of this rulemaking.

Finally, the hazards of transporting

radioactive waste from storage sites to

the WIPP is of great concern to the

public. Transportation is entirely

outside EPA’s general authority for

regulating radioactive waste. Moreover,

in the WIPP LWA, Congress did not

authorize any role for EPA to regulate

transportation. Instead, the WIPP LWA

reiterated that DOE must adhere to

transportation requirements enforced by

the U.S. Nuclear Regulatory

Commission and the U.S. Department of

Transportation. (WIPP LWA, section 16)

Because all transportation requirements

for the WIPP are established and

enforced by other regulators, EPA does

not address the issue further in today’s

action.

The preamble section entitled, ‘‘What

is EPA’s response to general comments

received on the certification decision?’’

provides further discussion of general

issues, including several related to the

scope of EPA’s certification rulemaking.

C. Compliance With Other

Environmental Laws and Regulations

The WIPP must comply with a

number of other environmental and

safety regulations in addition to EPA’s

disposal regulations—including, for

example, the Solid Waste Disposal Act

and EPA’s environmental standards for

the management and storage of

radioactive waste. Various regulatory

agencies are responsible for overseeing

the enforcement of these Federal laws.

For example, the WIPP’s compliance

with EPA’s radioactive waste

management regulations, found at

Subpart A of 40 CFR Part 191, is

addressed by an EPA guidance

document which describes how EPA

intends to implement Subpart A at the

WIPP. (Copies of the WIPP Subpart A

Guidance are available by calling the

WIPP Information Line at 1–800–331–

WIPP or from EPA’s WIPP home page at

www.epa/gov/radiation/wipp.)

Enforcement of some parts of the

hazardous waste management

regulations has been delegated to the

State of New Mexico. The State’s

authority for such actions as issuing a

hazardous waste operating permit for

the WIPP is in no way affected by EPA’s

certification decision. It is the

responsibility of the Secretary of Energy

to report the WIPP’s compliance with all

applicable Federal laws pertaining to

public health and the environment.43

Compliance with environmental or
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27401

44 5 U.S.C. 553.

public health regulations other than

EPA’s disposal regulations and WIPP

compliance criteria is not addressed by

today’s action.

XI. How Has the Public Been Involved

in EPA’s WIPP Activities?

Section 8(d)(2) of the WIPP LWA

requires that the Administrator’s

certification decision be conducted by

informal (or ‘‘notice-and-comment’’)

rulemaking pursuant to Section 4 of the

Administrative Procedure Act (‘‘APA’’).

Notice-and-comment rulemaking under

the APA requires that an agency provide

notice of a proposed rulemaking, an

opportunity for the public to comment

on the proposed rule, and a general

statement of the basis and purpose of

the final rule.44

The WIPP compliance criteria, at

Subpart D of 40 CFR Part 194,

established a process of public

participation that exceeds the APA’s

basic requirements, and provides the

public with the opportunity to

participate in the regulatory process at

the earliest opportunity. The WIPP

compliance criteria contain provisions

that require EPA to: publish an advance

notice of proposed rulemaking

(‘‘ANPR’’) in the Federal Register; allow

public comment on DOE’s compliance

certification application (‘‘CCA’’) for at

least 120 days, prior to proposing a

certification decision; hold public

hearings in New Mexico, if requested,

on the CCA; provide a minimum of 120

days for public comment on EPA’s

proposed certification decision; hold

public hearings in New Mexico on

EPA’s proposal; produce a document

summarizing the Agency’s

consideration of public comments on

the proposal, and maintain

informational dockets in the State of

New Mexico to facilitate public access

to the voluminous technical record,

including the CCA. The EPA has

complied with each of these

requirements.

A. Public Involvement Prior to Proposed

Rule

The EPA received DOE’s CCA on

October 29, 1996. Copies of the CCA

and all the accompanying references

submitted to EPA were placed in EPA’s

dockets in New Mexico and

Washington, DC. On November 15,

1996, the Agency published in the

Federal Register (61 FR 58499) an

ANPR announcing that the CCA had

been received, and announcing the

Agency’s intent to conduct a rulemaking

to certify whether the WIPP facility will

comply with the disposal regulations.

The notice also announced a 120-day

public comment period, requested

public comment ‘‘on all aspects of the

CCA,’’ and stated EPA’s intent to hold

public hearings in New Mexico.

The EPA published a separate notice

in the Federal Register announcing

hearings to allow the public to address

all aspects of DOE’s certification

application. (62 FR 2988) Public

hearings were held on February 19, 20

and 21, 1997, in Carlsbad, Albuquerque

and Santa Fe, New Mexico, respectively.

In addition to the public hearings, EPA

held three days of meetings in New

Mexico, on January 21, 22 and 23, 1997,

with the principal New Mexico

Stakeholders. Detailed summaries of

these meeting were placed in Docket A–

93–02, Category II–E.

The Agency received over 220 sets of

written and oral public comments in

response to the ANPR. The Agency

reviewed all public comments

submitted during the ANPR 120-day

comment period or presented at the

preliminary meetings with stakeholders.

The EPA provided responses to these

comments in the preamble to the

proposed certification as well as in the

compliance application review

documents (‘‘CARDs’’) for the proposed

certification decision. The CARDs also

addressed late comments—and

comments on the completeness of DOE’s

CCA—received after the close of the

public comment period (on March 17,

1997) but before August 8, 1997. (62 FR

27996–27998) All relevant public

comments, whether received in writing,

or orally during the public hearings,

were considered by the Agency as the

proposed certification decision was

developed. For further discussion of

EPA’s completeness determination and

other pre-proposal activities, see the

preamble to the proposed certification

decision, 62 FR 58794–58796.

B. Proposed Certification Decision

On October 30, 1997, EPA published

a Notice of Proposed Rulemaking in the

Federal Register, fulfilling the

requirements of the WIPP compliance

criteria at § 194.62. (62 FR 58792–

58838) The notice announced the

Administrator’s proposed decision,

pursuant to section 8(d)(1) of the WIPP

LWA, as amended, to issue a

certification that the WIPP facility will

comply with the disposal regulations,

and solicited comment on the proposal.

The notice also marked the beginning of

a 120-day public comment period on

EPA’s proposed certification decision.

Finally, the notice announced that

public hearings would be held in New

Mexico during the public comment

period.

C. Public Hearings on Proposed Rule

Further information on the hearings

was provided in a Federal Register

notice published on December 5, 1997.

(62 FR 64334–64335) The Agency

conducted hearings in three cities in

New Mexico—Carlsbad, Albuquerque,

and Santa Fe—on January 5 through 9,

1998. The EPA took a number of steps

to ensure that citizens were aware of the

hearings and to accommodate requests

to testify before the EPA panel. For

example, EPA placed forty-six notices in

newspapers across the State to advertise

the hearings and provided a manned,

toll-free telephone line for preregistration. The Agency also allowed

on-site registration, and extended the

hours of the hearings in both

Albuquerque and Santa Fe in order to

allow everyone present who wished to

testify the opportunity to do so.

D. Additional Public Input on the

Proposed Rule

In addition to the public hearings,

EPA held two days of meetings in New

Mexico, on December 10–11, 1997, with

the principal New Mexico stakeholders,

including the New Mexico Attorney

General’s Office, the New Mexico

Environmental Evaluation Group

(‘‘EEG’’), Concerned Citizens for Nuclear

Safety, Citizens for Alternatives to

Radioactive Dumping, and Southwest

Research and Information Center.

Detailed summaries of these meetings

were placed in Docket A–93–02, Item

IV–E–8. Additional meetings were also

held in January 1998 in New Mexico

and Washington, DC with the New

Mexico EEG (IV–E–10 and IV–E–11) and

other stakeholders (IV–E–11).

In response to concerns expressed in

meetings with stakeholders and in

public hearings, EPA performed

additional analyses of air drilling (a

specialized drilling method which

stakeholders raised as an issue which

could potentially affect the WIPP if it

occurred near the site). In light of the

significant public interest in this issue,

EPA conducted its analysis and released

its report during the comment period on

the proposed rule, in order to allow an

opportunity for the public to comment

on EPA’s technical analysis. The

Agency published a Federal Register

notice of availability for the report and

provided a 30-day public comment

period. (63 FR 3863; January 27, 1998)

The report was placed in the public

docket and also sent electronically to a

number of interested stakeholders,

including the New Mexico Attorney

General, the New Mexico

Environmental Evaluation Group,

Citizens for Alternatives to Radioactive
27402 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

Dumping, Concerned Citizens for

Nuclear Safety, and Southwest Research

and Information Center.

E. Final Certification Decision, Response

to Comments Document

Today’s notice of EPA’s final

certification decision pursuant to

section 8(d)(1) of the WIPP LWA fulfills

the requirement of the WIPP compliance

criteria at § 194.63(a). Also in

accordance with § 194.63(b), EPA is

publishing a document, accompanying

today’s action and entitled ‘‘Response to

Comments,’’ which contains the

Agency’s response to all significant

comments received during the comment

period on the proposed certification

decision. (Docket A–93–02, Item V–C–1)

(For further discussion of EPA’s

treatment of ANPR and other preproposal comments, refer to the

preamble to the proposed rule, 62 FR

58794–58796.) All comments received

by EPA, whether written or oral, were

given equal consideration in developing

the final rule. All comments received by

the Agency were made available for

public inspection through the public

docket. (Docket A–93–02, Categories IV–

D, IV–F, and IV–G)

F. Dockets

In accordance with 40 CFR 194.67,

EPA maintains a public docket (Docket

A–93–02) that contains all information

used to support the Administrator’s

proposed and final decisions on

certification. The Agency established

and maintains the formal rulemaking

docket in Washington, D.C., as well as

informational dockets in three locations

in the State of New Mexico (Carlsbad,

Albuquerque, and Santa Fe). The docket

consists of all relevant, significant

information received to date from

outside parties and all significant

information considered by the

Administrator in reaching a certification

decision regarding whether the WIPP

facility will comply with the disposal

regulations. The EPA placed copies of

the CCA in Category II–G of the docket.

The Agency placed supplementary

information received from DOE in

response to EPA requests in Categories

II–G and II–I.

The final certification decision and

supporting documentation can be found

primarily in the following categories of

Docket A–93–02: Category V–A (final

rule and preamble), Category V–B

(Compliance Application Review

Documents and Technical Support

Documents), and Category V–C

(Response to Comments document).

The hours and locations of EPA’s

public information dockets are as

follows: Docket No. A–93–02, located in

room 1500 (first floor in Waterside Mall

near the Washington Information

Center), U.S. Environmental Protection

Agency, 401 M Street, S.W.,

Washington, D.C., 20460 (open from

8:00 a.m. to 4:00 p.m. on weekdays); 2)

EPA’s docket in the Government

Publications Department of the

Zimmerman Library of the University of

New Mexico located in Albuquerque,

New Mexico, (open from 8:00 a.m. to

9:00 p.m. on Monday through Thursday,

8:00 a.m. to 5:00 p.m. on Friday, 9:00

a.m. to 5:00 p.m. on Saturday, and 1:00

p.m. to 9:00 p.m. on Sunday); 3) EPA’s

docket in the Fogelson Library of the

College of Santa Fe in Santa Fe, New

Mexico, located at 1600 St. Michaels

Drive (open from 8:00 a.m. to 12:00

midnight on Monday through Thursday,

8:00 a.m. to 5:00 p.m. on Friday, 9:00

a.m. to 5:00 p.m. on Saturday, 1:00 p.m.

to 9:00 p.m. on Sunday); and 4) EPA’s

docket in the Municipal Library of

Carlsbad, New Mexico, located at 101 S.

Halegueno (open from 10:00 a.m. to 9:00

p.m. on Monday through Thursday,

10:00 a.m. to 6:00 p.m. on Friday and

Saturday, and 1:00 p.m. to 5:00 p.m. on

Sunday). As provided in 40 CFR Part 2,

a reasonable fee may be charged for

photocopying docket materials.

XII. How Will the Public be Involved in

EPA’s Future WIPP Activities?

The EPA’s regulatory role at the WIPP

does not end with its initial certification

decision. The Agency’s future WIPP

activities will include periodic

recertifications, review of DOE reports

on activities at the WIPP, assessment of

waste characterization and QA programs

at waste generator sites, announced and

unannounced inspections of the WIPP

and other facilities, and possibly

modification, revocation, or suspension

of the certification for cause. These

activities are described above in the

preamble section entitled ‘‘EPA’s Future

Role at the WIPP.’’ The EPA has

provided for public involvement in

these activities through rulemaking

procedures, Federal Register notices

and public comment periods, and by

making information available in its

public dockets. (See the preamble

sections entitled ‘‘Dockets’’ and ‘‘Where

can I get more information about EPA’s

WIPP activities?’’ for more information

regarding EPA’s rulemaking docket.)

While a suspension may be initiated

at the discretion of the Administrator in

order to promptly reverse or mitigate a

potential threat to public health, any

modification or revocation of the

certification will be conducted through

rulemaking. (§§ 194.65–66) To modify

or revoke the certification, EPA will first

publish a Notice of Proposed

Rulemaking in the Federal Register.

This notice will announce EPA’s

proposed action, describe the basis for

the decision, and provide the

opportunity for public comment on the

proposal. Documentation related to the

decision will be made available to the

public through EPA’s docket. Any final

rule on modification or revocation will

also be published in the Federal

Register. In addition, EPA will release a

document which summarizes and

responds to significant public comments

received on its proposal.

The recertification process—EPA’s

periodic review of the WIPP’s continued

compliance with the disposal

regulations and WIPP compliance

criteria—will include many of the same

elements as notice-and-comment

rulemaking. For example, EPA will

publish a Federal Register notice

announcing its intent to conduct such

an evaluation. The certification

application for recertification will be

placed in the docket, and at least a 30-

day period will be provided for

submission of public comments. The

Agency’s decision on whether to

recertify the WIPP facility will again be

announced in a Federal Register notice.

(§ 194.64)

Although not required by the APA,

the WIPP LWA, or the WIPP compliance

criteria, EPA intends to place in the

docket all inspection or audit reports

and annual reports by DOE on

conditions and activities at the WIPP.

The Agency also plans to docket

information pertaining to the

enforcement of certification conditions.

For the enforcement of Conditions 2 and

3 (regarding quality assurance (‘‘QA’’)

and waste characterization programs at

waste generator sites), a number of

additional steps will be taken. As

described in § 194.8 of the WIPP

compliance criteria, before approving

QA and waste characterization controls

at generator sites, EPA will publish a

Federal Register notice announcing

EPA inspections or audits. The requisite

plans and other appropriate inspection

or audit documentation will be placed

in the docket, and the public will be

allowed the opportunity to submit

written comments. A comment period of

at least 30 days will be provided. Thus,

EPA’s decisions on whether to approve

waste generator QA program plans and

waste characterization controls’—and

thus, to allow shipment of specific

waste streams for disposal at the

WIPP’—will be made only after EPA has

conducted an inspection or audit of the

waste generator site and after public

comment has been solicited on the

matter. The Agency’s decisions will be

conveyed by a letter from EPA to DOE.
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27403

A copy of the letter, as well as the

results of any inspections or audits, will

be placed in EPA’s docket.

XIII. Where Can I Get More

Information About EPA’s WIPP

Activities?

The EPA’s docket functions as the

official file for Agency rulemakings. The

EPA places all information used to

support its proposed and final decisions

in the docket, which is available for

review by the public. For the WIPP

certification rulemaking, information is

placed in Air Docket Number A–93–02.

The official docket is located in

Washington, DC, and informational

dockets are provided in three cities in

New Mexico. (See the ‘‘Dockets’’ section

of this preamble for more information

on the location and hours of EPA’s

WIPP dockets.) The contents of the

docket include technical information

received from outside parties and other

information considered by EPA in

reaching a certification decision, as well

as the Agency’s rationale for its

decision. The technical support

documents which describe the basis for

EPA’s certification decision are

discussed below; sources of more

general information on EPA’s WIPP

activities are also addressed.

A. Technical Support Documents

For more specific information about

the basis for EPA’s certification

decision, there are a number of

technical support documents available.

The Compliance Application Review

Documents, or CARDs, contain the

detailed technical rationale for EPA’s

certification decision. This document is

found at Docket A–93–02, Item V–B–2.

The CARDs discuss DOE’s

compliance with the individual

requirements of the WIPP compliance

criteria. Each CARD is a section in the

document which is numbered according

to the section of 40 CFR Part 194 to

which it pertains. For example, CARD

23 addresses § 194.23, ‘‘Models and

Computer Codes.’’ Each CARD: restates

the specific requirement, identifies

relevant information expected in the

CCA, explains EPA’s compliance review

criteria, summarizes DOE’s approach to

compliance, and describes EPA’s

compliance review and decision. The

CARDs also list additional EPA

technical support documents and any

other references used by EPA in

rendering its decision on compliance.

All technical support documents and

references are available in Docket A–93–

02 with the exception of generally

available references and those

documents already maintained by DOE

or its contractors in locations accessible

to the public. (Instructions for obtaining

access to DOE documents can be found

at Docket A–93–02, Item V–B–1.)

B. WIPP Information Line, Mailing List,

and Internet Homepage

For more general information and

updates on EPA’s WIPP activities,

interested citizens may contact EPA’s

toll-free WIPP Information Line at 1–

800–331–WIPP. The hotline offers a

recorded message, in both English and

Spanish, about current EPA WIPP

activities, upcoming meetings, and

publications. Callers are also offered the

option of joining EPA’s WIPP mailing

list. Periodic mailings, including a WIPP

Bulletin and fact sheets related to

specific EPA activities, are sent to

members of the mailing list (currently

numbering over 800). The WIPP internet

homepage, at www.epa.gov/radiation/

wipp, provides general information on

EPA’s regulatory oversight of the WIPP.

Federal Register notices are also

announced on the homepage, and a

number of documents (ranging from

outreach materials and hearings

transcripts to technical support

documents) are available to review or

download.

XIV. With What Regulatory and

Administrative Requirements Must

This Rulemaking Comply?

A. Executive Order 12866

Under Executive Order 12866, (58 FR

51735; October 4, 1993), the Agency

must determine whether the regulatory

action is ‘‘significant’’ and therefore

subject to OMB review and the

requirements of the Executive Order.

The Order defines ‘‘significant

regulatory action’’ as one that is likely

to result in a rule that may: (1) have an

annual effect on the economy of $100

million or more or adversely affect in a

material way the economy, a sector of

the economy, productivity, competition,

jobs, the environment, public health or

safety, or State, local, or tribal

governments or communities; (2) create

a serious inconsistency or otherwise

interfere with an action taken or

planned by another agency; (3)

materially alter the budgetary impact of

entitlements, grants, user fees, or loan

programs or the rights and obligations of

recipients thereof; or (4) raise novel

legal or policy issues arising out of legal

mandates, the President’s priorities, or

the principles set forth in the Executive

Order. Pursuant to the terms of

Executive Order 12866, it has been

determined that this final rule is a

‘‘significant regulatory action’’ because

it raises novel policy issues which arise

from legal mandates. As such, this

action was submitted to OMB for

review. Changes made in response to

OMB suggestions or recommendations

are documented in the public record.

B. Regulatory Flexibility

The Regulatory Flexibility Act

(‘‘RFA’’) generally requires an agency to

conduct a regulatory flexibility analysis

of any rule subject to notice and

comment rulemaking requirements

unless the agency certifies that the rule

will not have a significant economic

impact on a substantial number of small

entities. Small entities include small

businesses, small not-for-profit

enterprises, and small governmental

jurisdictions. This final rule will not

have a significant impact on a

substantial number of small entities

because it sets forth requirements which

apply only to Federal agencies.

Therefore, I certify that this action will

not have a significant economic impact

on a substantial number of small

entities.

C. Paperwork Reduction Act

The EPA has determined that this

proposed rule contains no information

collection requirements as defined by

the Paperwork Reduction Act (44 U.S.C.

3501 et seq).

D. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates

Reform Act of 1995 (‘‘UMRA’’), Pub. L.

104–4, establishes requirements for

Federal agencies to assess the effects of

their regulatory actions on State, local

and tribal governments and the private

sector. Pursuant to Title II of the UMRA,

EPA has determined that this regulatory

action is not subject to the requirements

of sections 202 and 205, because this

action does not contain any ‘‘federal

mandates’’ for State, local, or tribal

governments or for the private sector.

The rule implements requirements that

are specifically set forth by the Congress

in the Waste Isolation Pilot Plant Land

Withdrawal Act (Pub. L. 102–579) and

that apply only to Federal agencies.

E. Executive Order 12898

Pursuant to Executive Order 12898

(59 FR 7629, February 16, 1994),

entitled ‘‘Federal Actions to Address

Environmental Justice in Minority

Populations and Low-Income

Populations,’’ the Agency has

considered environmental justice

related issues with regard to the

potential impacts of this action on the

environmental and health conditions in

low-income, minority, and native

American communities. The EPA has

complied with this mandate. The

requirements specifically set forth by
27404 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

the Congress in the Waste Isolation Pilot

Plant Land Withdrawal Act (Pub. L.

102–579), which prescribes EPA’s role

at the WIPP, did not provide authority

for EPA to examine impacts in the

communities in which wastes are

produced, stored, and transported, and

Congress did not delegate to EPA the

authority to consider alternative

locations for the WIPP.

The EPA involved minority and lowincome populations early in the

rulemaking process. In 1993 EPA

representatives met with New Mexico

residents and government officials to

identify the key issues that concern

them, the types of information they

wanted from EPA, and the best ways to

communicate with different sectors of

the New Mexico public. The feedback

provided by this group of citizens

formed the basis for EPA’s WIPP

communications and consultation plan.

To help citizens, including a significant

Hispanic population in Carlsbad and the

nearby Mescalero Indian Reservation,

stay abreast of EPA’s WIPP-related

activities, the Agency developed many

informational products and services.

The EPA translated into Spanish many

documents regarding WIPP, including

educational materials and fact sheets

describing EPA’s WIPP oversight role

and the radioactive waste disposal

standards. The EPA also established a

toll-free WIPP Information Line,

recorded in both English and Spanish,

providing the latest information on

upcoming public meetings,

publications, and other WIPP-related

activities. The EPA also developed a

vast mailing list, which includes many

low-income, minority, and native

American groups, to systematically

provide interested parties with copies of

EPA’s public information documents

and other materials. Even after the final

rule, EPA will continue its efforts

toward open communication and

outreach.

F. Small Business Regulatory

Enforcement Fairness Act of 1996

The Congressional Review Act, 5

U.S.C. 801 et seq., as added by the Small

Business Regulatory Enforcement

Fairness Act of 1996, generally provides

that before a rule may take effect, the

agency promulgating the rule must

submit a rule report, which includes a

copy of the rule, to each House of the

Congress and to the Comptroller General

of the United States. Section 804,

however, exempts from section 801 the

following types of rules: rules of

particular applicability; rules relating to

agency management or personnel; and

rules of agency organization, procedure,

or practice that do not substantially

affect the right or obligations of nonagency parties. (5 U.S.C. 804(3)) The

EPA is not required to submit a rule

report regarding today’s action under

section 801 because this is a rule of

particular applicability.

G. National Technology Transfer &

Advancement Act of 1995

Section 12 of the National Technology

Transfer & Advancement Act of 1995 is

intended to avoid ‘‘re-inventing the

wheel.’’ It aims to reduce the costs to

the private and public sectors by

requiring federal agencies to draw upon

any existing, suitable technical

standards used in commerce or

industry. To comply with the Act, EPA

must consider and use ‘‘voluntary

consensus standards,’’ if available and

applicable, when implementing policies

and programs, unless doing so would be

‘‘inconsistent with applicable law or

otherwise impractical.’’ The EPA has

determined that this regulatory action is

not subject to the requirements of

National Technology Transfer &

Advancement Act of 1995 as this

rulemaking is not setting any technical

standards.

H. Executive Order 13045—Children’s

Health Protection

This final rule is not subject to E.O.

13045, entitled ‘‘Protection of Children

from Environmental Health Risks and

Safety Risks’’ (62 FR 19885, April 23,

1997), because it does not involve

decisions on environmental health risks

or safety risks that may

disproportionately affect children.

List of Subjects in 40 CFR Part 194

Environmental protection,

Administrative practice and procedure,

Nuclear materials, Radionuclides,

Plutonium, Radiation protection,

Uranium, Transuranics, Waste treatment

and disposal.

Dated: May 13, 1998.

Carol M. Browner,

Administrator.

For the reasons set out in the

preamble, 40 CFR Part 194 is amended

as follows.

PART 194—CRITERIA FOR THE

CERTIFICATION AND RECERTIFICATION OF THE WASTE

ISOLATION PILOT PLANT’S

COMPLIANCE WITH THE 40 CFR PART

191 DISPOSAL REGULATIONS

1. The authority citation for part 194

is revised to read as follows:

Authority: Pub. L. 102–579, 106 Stat. 4777,

as amended by Pub. L. 104–201,110 Stat.

2422; Reorganization Plan No. 3 of 1970, 35

FR 15623, Oct. 6, 1970, 5 U.S.C. app. 1;

Atomic Energy Act of 1954, as amended, 42

U.S.C. 2011–2296 and 10101–10270.

2. In § 194.2, a definition is added in

alphabetical order to read as follows:

§ 194.2 Definitions.

* * * * *

Administrator’s authorized

representative means the director in

charge of radiation programs at the

Agency.

3. Section 194.8 is added to subpart

A to read as follows:

§ 194.8 Approval Process for Waste

Shipment from Waste Generator Sites for

Disposal at the WIPP

(a) Quality Assurance Programs at

Waste Generator Sites. The Agency will

determine compliance with

requirements for site-specific quality

assurance programs as set forth below:

(1) Upon submission by the

Department of a site-specific quality

assurance program plan the Agency will

evaluate the plan to determine whether

it establishes the applicable Nuclear

Quality Assurance (NQA) requirements

of § 194.22(a)(1) for the items and

activities of §§ 194.22(a)(2)(i),

194.24(c)(3) and 194.24(c)(5). The

program plan and other documentation

submitted by the Department will be

placed in the dockets described in

§ 194.67.

(2) The Agency will conduct a quality

assurance audit or an inspection of a

Department quality assurance audit at

the relevant site for the purpose of

verifying proper execution of the sitespecific quality assurance program plan.

The Agency will publish a notice in the

Federal Register announcing a

scheduled inspection or audit. In that or

another notice, the Agency will also

solicit public comment on the quality

assurance program plan and appropriate

Department documentation described in

paragraph (a)(1) of this section. A public

comment period of at least 30 days will

be allowed.

(3) The Agency’s written decision

regarding compliance with the requisite

quality assurance requirements at a

waste generator site will be conveyed in

a letter from the Administrator’s

authorized representative to the

Department. No such compliance

determination shall be granted until

after the end of the public comment

period described in paragraph (a)(2) of

this section. A copy of the Agency’s

compliance determination letter will be

placed in the public dockets in

accordance with § 194.67. The results of

any inspections or audits conducted by

the Agency to evaluate the quality

assurance programs described in

paragraph (a)(1) of this section will also
Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations 27405

be placed in the dockets described in

§ 194.67.

(4) Subsequent to any positive

determination of compliance as

described in paragraph (a)(3) of this

section, the Agency intends to conduct

inspections, in accordance with

§§ 194.21 and 194.22(e), to confirm the

continued compliance of the programs

approved under paragraphs (a)(2) and

(a)(3) of this section. The results of such

inspections will be made available to

the public through the Agency’s public

dockets, as described in § 194.67.

(b) Waste Characterization Programs

at Waste Generator Sites. The Agency

will determine compliance with the

requirements for use of process

knowledge and a system of controls at

waste generator sites as set forth below:

(1) For each waste stream or group of

waste streams at a site, the Department

must:

(i) Provide information on how

process knowledge will be used for

waste characterization of the waste

stream(s) proposed for disposal at the

WIPP; and

(ii) Implement a system of controls at

the site, in accordance with

§ 194.24(c)(4), to confirm that the total

amount of each waste component that

will be emplaced in the disposal system

will not exceed the upper limiting value

or fall below the lower limiting value

described in the introductory text of

paragraph (c) of § 194.24. The

implementation of such a system of

controls shall include a demonstration

that the site has procedures in place for

adding data to the WIPP Waste

Information System (‘‘WWIS’’), and that

such information can be transmitted

from that site to the WWIS database;

and a demonstration that measurement

techniques and control methods can be

implemented in accordance with

§ 194.24(c)(4) for the waste stream(s)

proposed for disposal at the WIPP.

(2) The Agency will conduct an audit

or an inspection of a Department audit

for the purpose of evaluating the use of

process knowledge and the

implementation of a system of controls

for each waste stream or group of waste

streams at a waste generator site. The

Agency will announce a scheduled

inspection or audit by the Agency with

a notice in the Federal Register. In that

or another notice, the Agency will also

solicit public comment on the relevant

waste characterization program plans

and Department documentation, which

will be placed in the dockets described

in § 194.67. A public comment period of

at least 30 days will be allowed.

(3) The Agency’s written decision

regarding compliance with the

requirements for waste characterization

programs described in paragraph (b)(1)

of this section for one or more waste

streams from a waste generator site will

be conveyed in a letter from the

Administrator’s authorized

representative to the Department. No

such compliance determination shall be

granted until after the end of the public

comment period described in paragraph

(b)(2) of this section. A copy of the

Agency’s compliance determination

letter will be placed in the public

dockets in accordance with § 194.67.

The results of any inspections or audits

conducted by the Agency to evaluate the

plans described in paragraph (b)(1) of

this section will also be placed in the

dockets described in § 194.67.

(4) Subsequent to any positive

determination of compliance as

described in paragraph (b)(3) of this

section, the Agency intends to conduct

inspections, in accordance with

§§ 194.21 and 194.24(h), to confirm the

continued compliance of the programs

approved under paragraphs (b)(2) and

(b)(3) of this section. The results of such

inspections will be made available to

the public through the Agency’s public

dockets, as described in § 194.67.

4. Appendix A to Part 194 is added

to read as follows:

Appendix A to Part 194—Certification

of the Waste Isolation Pilot Plant’s

Compliance With the 40 CFR Part 191

Disposal Regulations and the 40 CFR

Part 194 Compliance Criteria

In accordance with the provisions of the

WIPP Compliance Criteria of this part, the

Agency finds that the Waste Isolation Pilot

Plant (‘‘WIPP’’) will comply with the

radioactive waste disposal regulations at part

191, subparts B and C, of this chapter.

Therefore, pursuant to Section 8(d)(2) of the

WIPP Land Withdrawal Act (‘‘WIPP LWA’’),

as amended, the Administrator certifies that

the WIPP facility will comply with the

disposal regulations. In accordance with the

Agency’s authority under § 194.4(a), the

certification of compliance is subject to the

following conditions:

Condition 1: § 194.14(b), Disposal system

design, panel closure system. The

Department shall implement the panel seal

design designated as Option D in Docket A–

93–02, Item II–G–1 (October 29, 1996,

Compliance Certification Application

submitted to the Agency). The Option D

design shall be implemented as described in

Appendix PCS of Docket A–93–02, Item II–

G–1, with the exception that the Department

shall use Salado mass concrete (consistent

with that proposed for the shaft seal system,

and as described in Appendix SEAL of

Docket A–93–02, Item II–G–1) instead of

fresh water concrete.

Condition 2: § 194.22: Quality Assurance.

The Secretary shall not allow any waste

generator site other than the Los Alamos

National Laboratory to ship waste for

disposal at the WIPP until the Agency

determines that the site has established and

executed a quality assurance program, in

accordance with §§ 194.22(a)(2)(i),

194.24(c)(3) and 194.24(c)(5) for waste

characterization activities and assumptions.

The Agency will determine compliance of

site-specific quality assurance programs at

waste generator sites using the process set

forth in § 194.8.

Condition 3: § 194.24: Waste

Characterization. The Secretary may allow

shipment for disposal at the WIPP of legacy

debris waste at the Los Alamos National

Laboratory (‘‘LANL’’) that can be

characterized using the systems and

processes inspected by the Agency and

documented in Docket A–93–02, Item II–I–

70. The Secretary shall not allow shipment

of any waste from any additional LANL

waste stream(s) or from any waste generator

site other than LANL for disposal at the WIPP

until the Agency has approved the processes

for characterizing those waste streams for

shipment using the process set forth in

§ 194.8.

Condition 4: § 194.43, Passive institutional

controls.

(a) Not later than the final recertification

application submitted prior to closure of the

disposal system, the Department shall

provide, to the Administrator or the

Administrator’s authorized representative:

(1) a schedule for implementing passive

institutional controls that has been revised to

show that markers will be fabricated and

emplaced, and other measures will be

implemented, as soon as possible following

closure of the WIPP. Such schedule should

describe how testing of any aspect of the

conceptual design will be completed prior to

or soon after closure, and what changes to the

design of passive institutional controls may

be expected to result from such testing.

(2) documentation showing that the granite

pieces for the proposed monuments and

information rooms described in Docket A–

93–02, Item II–G–1, and supplementary

information may be: quarried (cut and

removed from the ground) without cracking

due to tensile stresses from handling or

isostatic rebound; engraved on the scale

required by the design; transported to the

site, given the weight and dimensions of the

granite pieces and the capacity of existing

rail cars and rail lines; loaded, unloaded, and

erected without cracking based on the

capacity of available equipment; and

successfully joined.

(3) documentation showing that archives

and record centers will accept the documents

identified and will maintain them in the

manner identified in Docket A–93–02, Item

II–G–1.

(4) documentation showing that proposed

recipients of WIPP information other than

archives and record centers will accept the

information and make use of it in the manner

indicated by the Department in Docket A–

93–02, Item II–G–1 and supplementary

information.

(b) Upon receipt of the information

required under paragraph (a) of this

condition, the Agency will place such

documentation in the public dockets

identified in § 194.67. The Agency will

determine if a modification to the
27406 Federal Register / Vol. 63, No. 95 / Monday, May 18, 1998 /Rules and Regulations

compliance certification in effect is

necessary. Any such modification will be

conducted in accordance with the

requirements at §§ 194.65 and 194.66.

[FR Doc. 98–13100 Filed 5–15–98; 8:45 am]

BILLING CODE 6560–50–P