58792 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 194

[FRL–5915–1]

RIN 2060–AG85

Criteria for the Certification and ReCertification of the Waste Isolation

Pilot Plant’s Compliance With the 40

CFR Part 191 Disposal Regulations:

Certification Decision

AGENCY: Environmental Protection

Agency.

ACTION: Proposed rule; opening of

public comment period.

SUMMARY: The Environmental Protection

Agency (‘‘EPA’’) is proposing to certify

that the Department of Energy’s (‘‘DOE’’)

Waste Isolation Pilot Plant (‘‘WIPP’’)

will comply with the radioactive waste

disposal regulations set forth at 40 CFR

Part 191 (Environmental Standards for

the Management and Disposal of Spent

Nuclear Fuel, High-Level and

Transuranic Radioactive Waste). 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, if finalized, would allow

the emplacement of radioactive waste in

the WIPP to begin, provided that all

other applicable health and safety

standards have been met. The proposed

certification would allow Los Alamos

National Laboratory to ship TRU waste

from specific waste streams for disposal

at the WIPP. However, the proposed

certification is subject to several

conditions, notably that EPA must

approve site-specific waste

characterization measures and quality

assurance plans before allowing other

waste generator sites to ship waste for

disposal at the WIPP. The Agency

proposes to amend 40 CFR Part 194 by

adding an appendix describing EPA’s

certification, and by adding a definition.

Finally, EPA is proposing its decision,

also pursuant to the LWA, that DOE

does not need to acquire existing oil and

gas leases near the WIPP in order to

meet the disposal regulations. Today’s

notice marks the beginning of a 120-day

public comment period on EPA’s

proposed certification decision, and on

the other proposed actions described

above.

DATES: Comments on today’s proposal

must be received by February 27, 1998.

Public hearings on today’s proposal will

be held in New Mexico. A separate

announcement will be published in the

Federal Register to provide public

hearing information.

ADDRESSES: Comments should be

submitted, in duplicate, to: Docket No.

A–93–02, Air Docket, Room M–1500

(LE–131), U.S. Environmental

Protection Agency, 401 M Street, SW.,

Washington, DC 20460. See additional

docket information in the

SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT:

Betsy Forinash or Scott Monroe;

telephone number (202) 233–9310;

address: Radiation Protection Division,

Center for the Waste Isolation Pilot

Plant, Mail Code 6602-J, U.S.

Environmental Protection Agency, 401

M Street SW., Washington, DC 20460.

For copies of the Compliance

Application Review Documents

supporting today’s proposal, contact

Scott Monroe at the above phone

number and address.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background

II. Statutory Authority

III. Purpose and Scope of Today’s Action

IV. Limits of EPA’s Regulatory Authority at

the WIPP

V. Public Participation

A. Advance Notice of Proposed

Rulemaking (ANPR)

B. Public Hearings on ANPR

C. Additional Public Input

D. Public Comments on ANPR

E. Completeness Determination

F. Public Comments on Completeness

G. Proposed Certification Decision

H. Final Certification Decision

I. Dockets

VI. National Academy of Sciences Report on

the WIPP

VII. Codification of EPA’s Certification

Decision

VIII. Determination of Whether the WIPP

Complies with the Disposal Regulations

A. Basis for EPA’s Compliance

Determination

B. Compliance Application Review

Documents (CARDs)

IX. Section 194.14, Content of Compliance

Certification Application

A. Site Characterization

B. Disposal System Design

C. Results of Assessments

D. Input Parameters to Performance

Assessments

E. Assurance Requirements

F. Waste Acceptance Criteria

G. Background Radiation

H. Topographic Maps

I. Past and Current Meteorological

Conditions

J. Other Information Needed for

Demonstration of Compliance

K. Conclusion

X. General Requirements

A. Section 194.22, Quality Assurance

B. Section 194.23, Models and Computer

Codes

1. Conceptual models

a. Description of conceptual models

b. Alternative conceptual models

c. Future states of the disposal system and

peer review

d. Public comments

2. Progression from conceptual models to

computer codes

a. Mathematical models

b. Public comments on mathematical

models

c. Numerical models

d. Computer codes

3. Quality assurance

4. Documentation of models and codes

a. Theoretical background

b. Descriptions of models

c. Parameters

d. Public comments on parameter values

e. Software licenses

f. Parameter correlation

5. EPA’s independent testing

C. Section 194.24, Waste Characterization

D. Section 194.25, Future State

Assumptions

E. Section 194.26, Expert Judgment

F. Section 194.27, Peer Review

XI. Containment Requirements

A. Section 194.31, Application of Release

Limits

B. Section 194.32, Scope of Performance

Assessments (PA)

C. Section 194.33, Consideration of Drilling

Events in PA

D. Section 194.34, Results of PA

1. Complementary cumulative distribution

functions (CCDFs)

2. Generation of the full range of CCDFs

3. Probability distributions and random

sampling of uncertain parameters

4. Sufficient number of CCDFs generated

5. Compliance of the mean CCDF

XII. Assurance Requirements

A. Section 194.41, Active Institutional

Controls

B. Section 194.42, Monitoring

C. Section 194.43, Passive Institutional

Controls

D. Section 194.44, Engineered Barriers

E. Section 194.45, Consideration of the

Presence of Resources

F. Section 194.46, Removal of Waste

XIII. Individual and Ground-water Protection

Requirements

A. Section 194.51, Consideration of

Protected Individual

B. Section 194.52, Consideration of

Exposure Pathways

C. Section 194.53, Consideration of

Underground Sources of Drinking Water

D. Section 194.54, Scope of Compliance

Assessments (CA)

E. Section 194.55, Results of CA

1. Uncertainty of CA

2. Probability distributions for uncertain

parameters

3. Sampling of uncertain parameters

4. Sufficient number of estimates generated

5. Display full range of CA results

6. Compliance with radiation dose and

radionuclide concentration limits

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

Leases

XV. Administrative Requirements

A. Executive Order 12866

B. Regulatory Flexibility

C. Paperwork Reduction Act
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58793

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, section 8(b).

5 50 FR 38066–38089 (September 19, 1985) and 58

FR 66398–66416 (December 20, 1993).

6 61 FR 5224–5245 (February 9, 1996), ‘‘Criteria

for the Certification and Re-certification of the

Waste Isolation Pilot Plant’s Compliance with the

40 CFR Part 191 Disposal Regulations.’’ (Certain

aspects of the Compliance Criteria were challenged

in the Court of Appeals for the D.C. Circuit. The

Court upheld the Compliance Criteria in their

entirety. State of New Mexico v. Envt’l Protection

Agency, No. 96–1107 (D.C. Cir. June 6, 1997)).

7WIPP LWA, section 8(d).

8 62 FR 9188 (February 28, 1997), Notice of

Availability for ‘‘Guidance for the Implementation

of EPA’s Radiation Protection Standards for

Continued

D. Unfunded Mandates Reform Act

E. Executive Order 12898

I. Background

Congress authorized development and

construction of the Waste Isolation Pilot

Plant (‘‘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

U.S. Department of Energy (‘‘DOE’’ or

‘‘the Department’’) is developing the

WIPP near Carlsbad in southeastern

New Mexico as a potential deep

geologic repository for the disposal of

defense transuranic (‘‘TRU’’) radioactive

waste. TRU waste consists of materials

containing alpha-emitting radioisotopes, with half-lives greater than

twenty years and atomic numbers

greater than 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, 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 on Federal lands 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 as weapons

are disassembled and additional

facilities are decontaminated and

decommissioned.

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.3 The purpose of today’s

action is to propose EPA’s certification

decision.

II. Statutory Authority

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.

The LWA delegates to EPA three main

tasks, to be completed sequentially, for

reaching a compliance certification

decision. First, EPA must finalize

general regulations which apply to all

sites—except Yucca mountain—for the

disposal of highly radioactive waste.4

The regulations, located at Subparts B

and C of 40 CFR Part 191 (‘‘disposal

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. The disposal regulations

were published in the Federal Register

in 1985 and 1993.5

Second, EPA must develop, by

rulemaking, criteria to implement and

interpret the generic radioactive waste

disposal regulations specifically for the

WIPP. EPA issued these ‘‘WIPP

Compliance Criteria,’’ which are found

at 40 CFR Part 194, in 1996.6 The

criteria describe in detail what

information DOE must submit for EPA’s

review, and clarify the basis on which

EPA’s compliance determination will be

made.

Third, EPA must review information

submitted by DOE and publish a

certification decision.7 Today’s action

constitutes EPA’s proposed certification

decision as required by section 8 of the

LWA. On October 29, 1996, DOE

submitted a compliance certification

application (‘‘CCA’’) containing

information intended to demonstrate

that WIPP will comply with the disposal

regulations. Since then, DOE has

submitted additional information. On

May 22, 1997, EPA announced that

DOE’s application was deemed to be

complete. (62 FR 27996–27998) EPA’s

evaluation of whether the WIPP will

comply with the disposal regulations is

made by comparing the CCA and other

relevant information—including

supplementary information requested

by EPA from DOE, and the results of

EPA’s confirmatory audits and

inspections—to the WIPP Compliance

Criteria. The Administrator’s

certification of compliance depends on

DOE demonstrating that it has satisfied

the specific requirements of the WIPP

Compliance Criteria.

III. Purpose and Scope of Today’s

Action

Today’s action is limited primarily to

the certification decision required under

section 8(d) of the LWA. In addition, the

proposal addresses the provision of

section 4(b)(5)(B) of the LWA which

requires EPA to determine whether

existing oil and gas leases in the vicinity

of the WIPP must be acquired by DOE.

EPA has decided that it is appropriate

to include this determination in this

rulemaking because Congress explicitly

conditioned emplacement of wastes in

the repository on DOE’s acquisition of

the specified leaseholds, unless EPA

determines that such acquisition is not

required. (LWA, section 7(b)(2)) While

Congress’ mandate that EPA make this

determination is separate and apart from

the section 8(d) mandate to conduct the

WIPP certification proceeding pursuant

to notice-and-comment rulemaking

procedures, EPA nonetheless believes it

appropriate to address the leases in this

rulemaking. The determination of

whether potential drilling on the

specified leases could possibly affect the

integrity of the repository is closely

related to the similar determinations

that must be made under §§ 194.32(c)

and 194.54(b) of the Compliance

Criteria. Moreover, EPA is committed to

the intent of Congress, clearly expressed

in the LWA, that the public be involved

in these important regulatory

determinations. Therefore, by including

this decision in this proposal, EPA is

providing the public with the

opportunity for input on this matter.

The Agency is proposing to add to the

Compliance Criteria an appendix

describing EPA’s certification decision

and to define the term ‘‘Administrator’s

authorized representative.’’ Except for

these additions, EPA’s proposed

decision regarding WIPP’s compliance

does not otherwise amend or affect the

final disposal regulations (at Subparts B

and C of 40 CFR Part 191), or the final

WIPP Compliance Criteria (at Subparts

A through D of 40 CFR Part 194).

Today’s proposal does not address all

the actions required of EPA by the LWA.

For example, the proposal does not

address compliance with EPA’s

radioactive waste management

regulations—found in Subpart A of 40

CFR Part 191—which are referenced in

section 9(a)(1)(A) of the LWA. Instead,

the Agency has issued, in a separate

action, guidance describing how EPA

intends to implement Subpart A at the

WIPP.8 For copies of the WIPP Subpart
58794 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

Management and Storage of Transuranic Waste at

the Waste Isolation Pilot Plant (’WIPP Subpart A

Guidance’).’’ 9 5 U.S.C. 553.

A Guidance (Document Number EPA

402–R–97–001), call the EPA WIPP

Information Line at 1–800–331–WIPP,

or write to Betsy Forinash, Center for

the Waste Isolation Pilot Plant, Mail

Code 6602–J, U.S. Environmental

Protection Agency, 401 M Street, SW.,

Washington, DC 20460.

Finally, today’s proposal does not

address requirements of the LWA which

must be fulfilled by other regulatory

agencies. Enforcement of some parts of

the hazardous waste regulations, for

example, 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 constrained by EPA’s

proposed certification decision.

IV. Limits of EPA’s Regulatory

Authority at the WIPP

As discussed above, the 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 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 Advanced Notice

of Proposed Rulemaking for today’s

proposal, a desire for the Agency to

oversee other aspects of WIPP’s

operation. In response to such concerns,

EPA must clarify that its authority to

regulate DOE and the WIPP is limited by

the 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

current rulemaking.

Several 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. EPA

must conduct its WIPP activities in

accordance with the intent of Congress

as expressed in the 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 the EPA as established in

the LWA and, thus, necessarily outside

the scope of this rulemaking.

Some commenters requested that EPA

consider certain factors in making its

certification decision. These factors

include: reviews by organizations other

than EPA, safety at other DOE facilities,

and the political or economic

motivations of interested parties.

Pursuant to the LWA, EPA’s

certification decision must be made

based on the WIPP Compliance Criteria

at 40 CFR Part 194, and in accordance

with requirements governing informal

rulemaking proceedings. EPA is tasked

only with examining the scope and

quality of relevant information, and

comparing such information to the

objective criteria of 40 CFR Part 194.

Where relevant, the Agency has

considered public comments and

outside reviews which support or refute

technical positions taken by DOE.

Emotional pleas, comments on the

motives of interested parties, and the

safety of sites or disposal methods other

than the WIPP are factors that are not

relevant to a determination of whether

DOE has demonstrated compliance with

the WIPP Compliance Criteria, and are

therefore outside the scope of this

rulemaking.

In addition, the hazards of

transporting radioactive waste from

storage sites to the WIPP have been of

great concern to the public. EPA has

received numerous public comments,

oral and written, concerning the

possible transport of TRU waste to the

WIPP. Transportation is entirely outside

EPA’s general authority for regulating

radioactive waste. Moreover, in the

LWA, Congress did not authorize any

role for EPA with respect to

transportation. Congress addressed

transportation issues by requiring DOE

to (1) use only shipping containers

approved by the Nuclear Regulatory

Commission; (2) notify in advance

States and Indian Tribes of the transport

of TRU waste through their

jurisdictions; (3) provide technical

assistance and funding to ensure that

jurisdictions along WIPP transportation

routes receive appropriate training for

accident prevention and emergency

preparedness; (4) provide transportation

safety assistance to States or Indian

tribes through whose jurisdictions TRU

waste will be transported; and (5) study

transportation alternatives. (LWA,

section 16) Transportation of radioactive

waste is regulated by the Nuclear

Regulatory Commission and the U.S.

Department of Transportation. Because

all transportation requirements for the

WIPP are established and enforced by

other regulators, EPA does not address

the issue further in this proposal.

V. Public Participation

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

that the Administrator’s certification

decision be conducted by informal (or

‘‘notice-and-comment’’) rulemaking

pursuant to Section 553 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 adopted.9

The WIPP is a first-of-a-kind project,

and New Mexico citizens have

expressed a great deal of interest in the

safety of the site. 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. EPA either has or

will comply with each of these

requirements.

In addition, EPA has taken other

measures to assure that the public is

involved in the present rulemaking.

EPA allowed the New Mexico

Environment Department, the New

Mexico Environmental Evaluation

Group, and more recently, the New

Mexico Attorney General’s Office as

well, to observe meetings between EPA

and DOE staff to discuss technical

issues during the pre-proposal period.

EPA also committed to summarize all

meetings between EPA and DOE

(including management level meetings
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58795

and meetings between EPA and DOE

legal staff) and to place such summaries

in the public docket. While these

commitments are not required by the

APA, EPA believes that they are useful

given the importance of this rulemaking

to the nation as a whole, and New

Mexico in particular.

A. Advance Notice of Proposed

Rulemaking (ANPR)

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. Upon

receipt of the CCA, EPA immediately

began its review of the application in

accordance with 40 CFR 194.11,

‘‘Completeness and accuracy of

compliance applications.’’ 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.

B. Public Hearings on ANPR

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.

All individuals who requested an

opportunity to address the EPA panel

during the hearings were afforded five

minutes if they were representing

themselves, or ten minutes if they were

representing a group. In Albuquerque

and Santa Fe, EPA extended the hours

of the hearings in order to accommodate

all individuals who requested that they

be allowed to address the panel.

C. Additional Public Input

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, including the New

Mexico Attorney General’s Office, the

New Mexico Environmental Evaluation

Group, 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,

Category II–E.

D. Public Comments on ANPR

The Agency received over 220 sets of

written and oral public comments in

response to the ANPR. All comments

received on the ANPR were made

available to members of the public

through the public docket. (Docket A–

93–02, Category II–H) In accordance

with 40 CFR 194.61(f), DOE submitted

to the Agency additional information

specifically addressing many of the

comments received; these submittals

were treated by EPA as public

comments.

The Agency reviewed all public

comments submitted during the ANPR

120-day comment period or presented at

the preliminary meetings with

stakeholders. Public comments received

in response to the ANPR generally

focused on the completeness of the

CCA, specific technical issues relating

to compliance with the disposal

regulations, and EPA’s approach to

public participation in accordance with

the provisions of the WIPP Compliance

Criteria, and pursuant to the LWA and

the APA.

The EPA is providing responses to

these comments in this preamble as well

as in the compliance application review

documents (‘‘CARDs’’) which are part of

today’s proposed certification decision.

The CARDs also address late

comments—and comments on

completeness (see below)—received

after the close of the public comment

period (on March 17, 1997) but before

August 8, 1997. 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. Comments received after

August 8 were considered by EPA, to

the extent possible, in its development

of the proposed rule, but were not

addressed in CARDs because of time

constraints. Such comments will be

addressed in the Response to Comments

document for EPA’s final certification

decision.

E. Completeness Determination

Section 8(d)(1)(B) of the LWA

establishes a one-year time frame for the

Administrator to reach a certification

decision regarding WIPP’s compliance

with the disposal regulations. Section

8(d)(4) of the LWA requires that EPA

make its certification determination

only after DOE has submitted the ‘‘full

application’’ to EPA. The Compliance

Criteria, at § 194.11, interpret these

requirements to mean one year from

receipt of a ‘‘complete’’ certification

application from DOE. This assures that

the one-year review period is devoted

exclusively to substantive, meaningful

review of the CCA.

Upon receipt of the CCA in October

1996, EPA began reviewing the CCA for

both completeness and, to the extent

possible, technical adequacy. Pursuant

to section 8(d)(1) of the LWA, EPA

provided requests to DOE for specific

information needed for completeness on

December 19, 1996. (Docket A–93–02,

Item II–I–1, Attachment 1) DOE

submitted the requested information

with letters dated January 17, January

24, February 7, February 14, and

February 26, 1997. (This

correspondence is available in Docket

A–93–02, Category II–I.) On May 16,

1997, the Administrator informed the

Secretary, in writing, that the CCA was

complete. The completeness

determination was announced in the

Federal Register on May 22, 1997. (62

FR 27996–27998)

The determination of completeness

meant only that all sections of the

disposal regulations and Compliance

Criteria had been addressed in the CCA.

The completeness determination did not

state or imply that compliance with the

disposal regulations or WIPP

Compliance Criteria had been achieved.

In short, the completeness

determination was an interim

administrative step to announce that the

CCA contained the information

necessary for the Agency to proceed

with its technical evaluation of

compliance.

Moreover, section 8(d)(1) of the LWA

specifically allows EPA to request

additional information ‘‘as needed to

certify’’ at any time. EPA made such

additional requests in letters to DOE

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–32, and II–I–37, respectively)

F. Public Comments on Completeness

The Agency received numerous

public comments regarding the timing

of the Administrator’s completeness

determination. While some comments

stated that the CCA was

administratively complete upon

submission, others argued that the CCA

was incomplete and simply should be

returned to DOE. The latter set of

commenters expressed that it was not

appropriate for the Agency to close the

public comment period on the ANPR

prior to the Administrator’s

determination of completeness, and that

the public hearings should be delayed

until after the completeness

determination. Other commenters
58796 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

10 National Research Council (NRC), ‘‘The

Disposal of Radioactive Wastes on Land’’ (National

Academy Press 1957).

requested an additional 120-day

comment period after the completeness

determination was issued, as well as an

additional set of public hearings during

such a comment period.

In making its completeness

determination, EPA considered public

comments which explicitly addressed

the issue of completeness and were

submitted to the docket or to EPA’s

Office of Radiation and Indoor Air. In

response to concerns expressed by

commenters, the Agency notified the

public in the Federal Register

announcement regarding the

completeness determination that EPA

would continue to accept public

comments on the CCA subsequent to the

completeness determination. (62 FR

27997) (Comments on completeness

received before August 8, 1997, are

addressed in more detail in the CARDs

supporting this proposal. Comments

received after August 8 will be

addressed in the Response to Comments

document for EPA’s final certification

rule.) In accordance with § 194.62, the

public is being afforded a 120-day

period in which to comment on today’s

proposal. This comment period will

provide the public with another

opportunity to comment on DOE’s CCA,

as well as an opportunity to address

EPA’s proposed certification decision.

Public comments received during and

after the ANPR comment period also

requested that EPA clarify what specific

material constitutes the ‘‘complete’’

CCA. This concern was raised because,

at EPA’s request, DOE supplemented the

docket with substantial additional

materials beyond what was initially

submitted on October 29, 1996. Many of

the issues raised by public comments

were addressed in a December 19, 1996

letter to DOE in which EPA identified

additional information necessary for the

CCA to constitute a complete

application. (Docket A–93–02, Item II–I–

1, Attachment 1) To address

completeness concerns, EPA requested

additional information on (among other

topics) site conditions, documentation

of computer codes, and the effects of

explosions—issues all identified in

public comments. DOE submitted the

requested information with letters dated

January 17, January 24, February 7,

February 14, and February 26, 1997. The

complete CCA consists of the

application that was submitted to EPA

on October 29, 1996, and supplementary

materials provided by DOE that were

identified by EPA, in the December 19

letter, as necessary for completeness. A

list of the specific items that comprise

the complete application is located in

Docket A–93–02, Item II–G–29. All

correspondence between DOE and EPA

regarding completeness of the CCA is

available in the Agency’s public

dockets. (Docket A–93–02, Category II–

I)

Other issues raised by commenters,

such as fluid injection scenarios, were

not considered relevant to the

completeness determination and instead

were addressed by EPA in its technical

comments to DOE.

G. Proposed Certification Decision

Today’s Notice of Proposed

Rulemaking for certification fulfills the

requirements of the WIPP Compliance

Criteria at § 194.62. Today’s notice

announces the Administrator’s

proposed decision, pursuant to section

8(d)(1) of the LWA, as amended, to issue

a certification that the WIPP facility will

comply with the disposal regulations,

and solicits comment on the proposal.

Today’s notice also marks the beginning

of a 120-day public comment period on

EPA’s proposed certification decision.

Finally, today’s notice announces that

public hearings will be held in New

Mexico during the public comment

period. Further information on the

hearings will be provided in a

subsequent Federal Register notice. Any

comments received on today’s notice

will be made available for inspection in

Docket A–93–02, Category IV–D.

H. Final Certification Decision

The Agency will publish a final rule

in the Federal Register announcing the

Administrator’s final decision, pursuant

to section 8(d)(1) of the LWA and in

accordance with the Compliance

Criteria at 40 CFR 194.63, whether to

issue a certification that the WIPP

facility will comply with the disposal

regulations. EPA will review comments

submitted on EPA’s proposed decision.

(Comments regarding the ANPR and

completeness that are addressed in the

CARDs for the proposed rule have

already been considered and will not be

addressed again in the Response to

Comments document for the final rule.)

A document summarizing significant

comments and issues arising from

comments received on today’s Notice of

Proposed Rulemaking, as well as the

Administrator’s response to such

significant comments and issues, will be

prepared and will be made available for

inspection in Docket A–93–02.

I. Dockets

In accordance with 40 CFR 194.67,

EPA maintains a public docket (Docket

A–93–02) that will contain 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 proposed

certification decision regarding whether

the WIPP facility will comply with the

disposal regulations. Copies of the CCA

were placed in Category II–G of the

docket. Supplementary information

received from DOE in response to EPA

requests was placed in Categories II–I

and II–G.

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.

VI. National Academy of Sciences

Report on the WIPP

The National Academy of Sciences

(‘‘NAS’’) has long considered the issue

of proper disposal of radioactive wastes.

The NAS first discussed the likely

suitability of salt formations as a

medium for geologic disposal of highlevel radioactive wastes in 1957.10 A

later study recommended the use of
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58797

11 NRC, ‘‘Disposal of Solid Radioactive Wastes in

Bedded Salt Deposits’’ (National Academy Press

1970).

12 NRC, ‘‘The Waste Isolation Pilot Plant: A

Potential Solution for the Disposal of Radioactive

Waste’’ (National Academy Press 1996), p. 12.

13 NAS never submitted official comments on

proposed 40 CFR Part 194. In contexts other than

the WIPP report, however, NAS has acknowledged

the impossibility of making decisions regarding

nuclear waste disposal based solely on scientific

information: ‘‘[I]t became clear in the course of our

work that designing the standards requires making

decisions based as much or more on policy

considerations than on science. It is equally clear

that there is no sharp dividing line between science

and policy.’’ [NRC, Technical Bases for Yucca

Mountain Standards (National Academy Press,

1995), p. viii] The rulemaking process used to

develop the WIPP compliance criteria provided a

forum for EPA to gather and weigh scientific

evidence, public concerns, and other policy issues

regarding the treatment of human intrusion in PA.

14 See, e.g., the RCRA Conditional No-Migration

Petition, 55 FR 47709.

bedded salt formations for geologic

disposal. 11

The NAS has provided specific

scientific and technical guidance to

DOE regarding the WIPP since the

inception of the NAS WIPP Committee

in 1978. In October 1996, the NAS

released a report assessing the long-term

safety and performance of the WIPP

disposal system. The report is available

in Docket A–93–02, Item II-A–38. The

WIPP committee’s schedule did not

allow for review of the CCA submitted

to EPA in October 1996; instead, the

committee examined a preliminary

performance assessment (‘‘PA’’)

conducted in 1992, and draft versions of

DOE’s CCA. For this reason and others,

the NAS noted that the report was ‘‘a

review of ongoing activities and should

be viewed as a progress report rather

than a final evaluation.’’ 12

The report reiterates NAS belief that

salt is an attractive medium for geologic

isolation of radioactive waste. Based on

its review of the 1992 PA, the committee

found no credible or probable scenario

for release of radionuclides from the

WIPP if it is undisturbed by human

intrusion. The report concluded that

disturbed scenarios—i.e., those

involving deliberate or unintentional

human intrusion—could compromise

the integrity of the disposal system.

Finally, the committee recommended

several changes intended to produce a

more technically defensible and more

easily understood PA.

EPA considered the NAS report in

developing its proposed certification

decision. Specific recommendations on

alternative modeling approaches or

other improvements to the 1992 PA

were considered by EPA in evaluating

whether the CCA is adequate. The

Agency treated such recommendations

as public comments on the ANPR, and

responds in detail to particular issues in

the CARDs supporting today’s proposal.

EPA did not give substantial

consideration to the committee’s general

conclusions on the PA because,

subsequent to the NAS review, EPA

required numerous changes to the

preliminary PA considered by the

committee. The committee

recommended that human intrusion

scenarios could be made less

speculative by refining probability

estimates for the occurrence of future

human activities, but suggested neither

a methodology for doing so, nor an

alternative approach to human intrusion

which could be implemented within the

framework of the Compliance Criteria.13

VII. Codification of EPA’s Certification

Decision

The requirements which apply to the

rulemaking process used to develop

EPA’s certification decision (including

measures for soliciting and considering

public input) do not prescribe what

form the final decision must take. In

analogous situations where EPA issues

or denies hazardous waste no-migration

petitions for landfills or other sites,

public notice of the decision is provided

by publication in the Federal Register,

and such notice serves as the record of

EPA’s action. 14 Because of the one-of-akind nature of the WIPP facility, EPA

has determined that it is appropriate to

provide a more permanent record of the

Agency’s decision. To that end, EPA’s

decision is being published in the

Federal Register and also will be

codified as an appendix to the WIPP

Compliance Criteria at 40 CFR Part 194.

A lasting record of EPA’s certification

decision will be established since the

appendix will be included each time in

the future that the Code of Federal

Regulations is compiled and published.

VIII. Determination of Whether the

WIPP Complies With the Disposal

Regulations

The proposed rule states the Agency’s

determination that the WIPP will

comply with the disposal standards and

Compliance Criteria, taken as a whole.

In addition, the proposal specifies all

conditions which apply to the

certification. As noted previously, EPA’s

certification of compliance depends on

DOE satisfying the specific requirements

of the WIPP Compliance Criteria. The

ensuing sections of the SUPPLEMENTARY

INFORMATION address each of the

technical WIPP Compliance Criteria in

turn; the Agency describes the basis for

evaluating compliance with each

criterion, and discusses briefly how the

CCA submitted by DOE, and other

relevant information, demonstrated

compliance with EPA’s requirements.

CARDs provide more detailed support

for EPA’s proposed decisions regarding

compliance with individual criteria.

The CARDs are available for public

review in Docket A-93–02, Category IIIB. See ‘‘additional docket information’’

in the SUPPLEMENTARY INFORMATION.

Not all sections of the WIPP

Compliance Criteria are discussed

below because not all the provisions of

40 CFR Part 194 are directly relevant to

an evaluation of compliance with the

disposal regulations. Some sections of

40 CFR Part 194—such as § 194.1,

‘‘Purpose, scope and applicability’’—are

entirely administrative in nature. Other

sections, including those related to

public participation, address procedural

aspects of the certification rulemaking.

Still others refer to future actions which

may occur, such as inspections or the

need to suspend an existing

certification. Such criteria are not

relevant to EPA’s analysis of whether

information in the CCA and elsewhere

demonstrates that the WIPP site will

comply with EPA’s disposal regulations.

Some of these criteria are addressed

elsewhere in the SUPPLEMENTARY

INFORMATION. For example, EPA’s

adherence to the public participation

requirements of the LWA and 40 CFR

Part 194 is documented under ‘‘public

participation.’’

A. Basis for EPA’s Compliance

Determination

EPA’s proposed certification decision

is based on the entire record available

to the agency, which is contained in

Docket A-93–02. The record consists of

the complete DOE CCA, supplementary

information submitted by DOE in

response to EPA requests for additional

information for technical sufficiency,

technical reports generated by EPA and

EPA contractors, EPA audit reports, and

public comments submitted on EPA’s

ANPR for the certification decision.

Thus, as contemplated by Congress,

EPA’s compliance determination is

based on more than the ‘‘complete’’

application. (LWA, section 8(d)(1)) 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.

Examples of such documents include

EPA technical and audit reports and

letters submitted by DOE (i.e., those

contained in Docket A–93–02, Category

II–I).

In response to public comments

regarding the precise materials EPA

considered in reaching today’s proposed

decision, the CARDs reference the
58798 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

relevant portion(s) of the October 29,

1996, CCA and any supplementary

information that was relied on in

reaching a particular proposed

compliance decision. All materials

which informed EPA’s proposed

decision have been placed in the WIPP

dockets or are otherwise publicly

available. EPA has specified in the

docket the location of all reference

materials to aid the public in its

evaluation of such information. A full

description of the supporting

documentation for EPA’s proposed

decision and a full list of the DOE

compliance documentation considered

by the Agency are located at Docket A–

93–02, Item III–B–1. Through these

means, the Agency believes the public

will have a clear indication of what

materials constitute the complete CCA,

and what materials constitute the record

basis for EPA’s proposed certification

decision.

B. Compliance Application Review

Documents (CARDs)

The preamble for today’s proposed

rule describes the basis for the Agency’s

compliance determination for each of

the relevant WIPP Compliance Criteria.

The detailed technical rationale for

EPA’s proposed decision is contained in

the Compliance Application Review

Documents (CARDs) supporting today’s

action. Taken as a whole, the CARDs are

analogous to the Background

Information Document usually provided

for EPA rulemakings. These documents

are found at Docket A–93–02, Item III–

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.’’ In the section of each

CARD called ‘‘Compliance Review

Criteria,’’ EPA restates the specific

requirement and identifies the relevant

information expected in the CCA, as

described in the ‘‘Compliance

Application Guidance for the WIPP: A

Companion Guide to 40 CFR Part 194’’

(‘‘CAG,’’ EPA 402–B–95–014, March

1996). EPA also clarifies the Agency’s

rationale for evaluating the CCA’s

completeness and technical adequacy.

After explaining the Agency’s

compliance review criteria, each CARD

summarizes DOE’s approach to

compliance and describes EPA’s

compliance review. CARDs also list

additional EPA technical support

documents and any other references

used by EPA in rendering a proposed

decision on compliance. All technical

support documents and references are

found 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. DOE

has committed to make such documents

readily available to the public.

Instructions for obtaining access to DOE

documents can be found at Docket A–

93–02, Item III–B–1.

Finally, CARDs contain EPA’s

response to comments received on the

Agency’s ANPR of November 15, 1996

(61 FR 58499) and on other comments

received prior to August 8, 1997. For

more discussion of EPA’s response to

these comments, see ‘‘Public

Participation’’ in the SUPPLEMENTARY

INFORMATION.

For technical information or more

detailed discussion on EPA’s evaluation

of compliance with any individual

provision of 40 CFR Part 194, readers

should refer to the corresponding CARD

in Docket A–93–02, Item III–B–2.

IX. Section 194.14, Content of

Compliance Certification Application

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.

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.

Much of the information referenced

by DOE as demonstrating compliance

with § 194.14, and EPA’s review of the

information, was principally used to

demonstrate compliance with other

sections of the Compliance Criteria.

Thus, this section of the preamble

discusses many of the requirements of

§ 194.14 only briefly because they are

fully discussed in other sections of the

preamble. EPA thoroughly reviewed

DOE’s compliance certification

application (‘‘CCA’’) submitted on

October 29, 1996, and additional

information submitted by DOE.

A. Site Characterization

40 CFR 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. The

characteristics of the site and

identification of potential pathways are

crucial to the conceptual models and

computer modeling that is done to

determine compliance with the

containment requirements at 40 CFR

191.13 and the individual and groundwater 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. EPA also required DOE to project

how geophysical, hydrogeologic and

geochemical conditions of the disposal

system would change due to the

presence of waste.

EPA examined the CCA and

determined that it and the supplemental

information provided by DOE 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. The CCA discussed that very few

potential pathways exist for

radionuclide transport. DOE projected

future geophysical, hydrogeologic and

geochemical conditions due to the

presence of waste. A brief overview of

the site is provided below.

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

precipitation increases were accounted

for in the performance assessment

(‘‘PA’’). The Delaware Basin contains

thick sedimentary deposits (over 15,000

feet (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 (∼200–250 million years old) Salado

Formation, which is composed

primarily of salt (halite).

DOE considered the primary geologic

units of concern to be (from below the

repository to the surface): (1) Castile

Formation (‘‘Castile’’), consisting of
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58799

anhydrite and halite with pressurized

brine pockets found locally throughout

the vicinity of the WIPP site; (2) Salado

Formation (‘‘Salado’’), consisting

primarily of halite with some anhydrite

interbeds and accessory minerals and

approximately 2,000 feet (600 meters)

thick; (3) Rustler Formation (‘‘Rustler’’),

containing salt, anhydrite, clastics, and

carbonates (primarily dolomite), with

the Culebra dolomite member of the

Rustler as the unit of most interest; and,

(4) 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 PA calculations because

they did not affect the performance of

the disposal system. See § 194.32 for a

detailed discussion of screening of

features, events, and processes.

DOE indicated that the major geologic

process in the vicinity of the WIPP is

dissolution. To the west, the slight (one

degree) dip in the Salado has exposed

the formation to dissolution processes,

and commenters argued that lateral

dissolution processes will affect the

WIPP’s ability to contain radionuclides.

However, DOE estimated that the

dissolution front will not reach the

WIPP site for at least hundreds of

thousands of years—well past the

regulatory time frame. EPA agrees with

DOE’s conclusion that while deep

dissolution has occurred elsewhere in

the Delaware Basin, the process of deep

dissolution, if it occurs under the WIPP

site, would occur at such a slow rate

that it would not affect the containment

capabilities of the WIPP during the

regulatory time period.

Many commenters suggested that

WIPP can not contain radionuclides

because WIPP is in a region of karst

(topography created by the dissolution

of rock). EPA reviewed information

submitted by DOE and stakeholders

regarding the occurrence and

development of karst at the WIPP (e.g.,

Docket A–93–02, Items II–H–46 and II–

D–102). EPA concluded that while the

WIPP site is in a karst region and karst

features are found to the west of the site

in Nash Draw, only limited evidence

exists that dissolution-related features

occur near the WIPP boundary (e.g.,

well WIPP–33). These features are

neither pervasive nor associated with

any identified preferential groundwater

flow paths or anomalies. WIPP field

mapping and site-specific hydrologic

information (e.g., well tracer tests) do

not indicate that any cavernous or other

karst-related flow is present at the WIPP

site. As stated in a technical document

submitted by one commenter, ‘‘the karst

phenomena do not appear to warrant a

rejection of the WIPP site.’’ (Docket A–

93–02, Item II–D–102) EPA agrees and

concludes that karst is not a problem at

WIPP and that geologic evidence of the

last approximately 500,000 years and

results from DOE’s groundwater

modeling indicate that future

development of karst at the WIPP is not

likely.

DOE conducted geologic studies and

field measurements as part of its

evaluation of the hydrology of the WIPP

site and identified two potential

pathways for radionuclides in the

disposal system: the Culebra dolomite

and Salado anhydrite markerbeds 138

and 139. However, only the Culebra

dolomite has the capability to transmit

significant amounts of radionuclides.

The Salado markerbeds have very low

permeability and are the primary

pathways in the undisturbed case. The

results of the CCA PA indicated that

radionuclide transport through the

anhydrites does not contribute

significantly to total releases. The

Culebra dolomite is a potential pathway

only in intrusion scenarios. Commenters

stated that the Dewey Lake should be

considered a potential pathway and

thus needed better characterization;

however, the CCA PA results indicated

that no contaminated brine traveled up

an intrusion borehole past the Culebra

to the Dewey Lake or other units. While

DOE did identify the Dewey Lake as a

potential underground source of

drinking water, the CCA PA results

indicated that the Dewey Lake did not

play an active role in radionuclide

release scenarios. EPA concludes that

the Culebra dolomite and the Salado

anhydrite markerbeds 138 and 139 are

the only ground-water radionuclide

transport pathways in the disposal

system.

As the primary radionuclide pathway

during an intrusion, the Culebra was the

subject of many public comments,

especially related to karst (discussed

above), Kd values (distribution

coefficients used in calculating the

retardation factor) and geochemistry and

flow directions. In DOE’s conceptual

model the Culebra is characterized as a

fractured dolomite that has dualporosity and acts to physically retard

movement of contaminants. In a dualporosity 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.

The CCA indicated that there were no

contributions to total releases from the

ground-water pathway. This was due, in

large part, to 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

was based on laboratory tests using

crushed rocks and small columns of

rock. EPA concluded that the laboratory

tests were conducted appropriately and

that the Kd values DOE derived from

this testing are reasonable given the

experimental evidence. However, EPA

believes that a lognormal distribution is

a more appropriate representation of the

data distribution, and required the use

of a lognormal distribution in the

Performance Assessment Verification

Test (PAVT). For further discussion of

the PAVT, refer to the preamble for

§ 194.34.

DOE indicated in the CCA that there

is considerable variation in the

groundwater chemistry of the Culebra

member of the Rustler Formation. In

addition, DOE provided supplemental

information pertaining to Culebra

groundwater flow and geochemistry

which contended that the observed

geochemistry and flow directions can be

explained with the ground-water basin

modeling. (Docket A–93–02, Item II–I–

17) The ground-water basin model

addressed near surface hydrologic

conditions (including the water table

and potential recharge areas) and

reconciled inconsistencies between the

geochemistry data and the current

ground-water flow direction.

The probability of intercepting a

Castile brine reservoir (i.e., brine

pocket) and the characteristics of a brine

reservoir once it has been hit were the

subject of many public comments as

well as a source of EPA concern.

Because of the low permeability of the

Salado Formation, there is no natural

connection between a Castile brine

pocket and the waste panel area.

However, in the case of a deep drilling

intrusion that goes through a waste

panel and into the Castile, it is possible

that the drilling will intercept brine in

the Castile and create a pathway for

Castile brine to flow into the repository

and interact with the waste.

In the 1992 PA, Sandia National

Laboratory (‘‘SNL’’) considered the

probability of hitting a brine pocket

under the waste area an uncertain

parameter that required sampling over a
58800 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

range of 0.25 to 0.62. This range of

probabilities was based on geophysical

work that suggested brine may be

present. For the CCA PA, SNL

conducted a new analysis based on a

geostatistical analysis of oil and gas

wells in the vicinity of WIPP. From this

study, SNL identified the probability of

hitting brine as 0.08, partly because the

brine is expected to be in fractures that

are oriented vertically or slightly less

than vertical. EPA reviewed the CCA

and public comments and concluded

that, while the probability of hitting a

brine pocket may be low, there was no

justification for assuming a fixed value

for such an uncertain parameter. EPA

therefore directed DOE, for the PAVT, to

change the probability of hitting a brine

pocket to a range that incorporated low

to moderate probabilities (0.01 to 0.6).

The potential volume of brine

reservoirs was also the subject of

numerous comments claiming that, in

the PA, DOE underestimated the brine

volume. DOE assumed that passive

institutional controls (‘‘PICs’’) will limit

the available brine pocket volume to

that within the area covered by the

surface berm used to mark the

subsurface location of the waste panels.

EPA reviewed information in the CCA,

public comments, and the SNL Records

Center. EPA concluded that the

approach of excluding Castile brine

pocket volumes based on the waste

panel ‘‘foot print’’ is inappropriate

because the efficacy of drilling in the

area outside the berm cannot be

reasonably defined. EPA directed DOE,

for the PAVT, to change the brine

pocket volume to a volume that is more

representative of data from site

characterization activities (i.e., the

WIPP–12 exploratory well). The PAVT

also omits the credit for PICs.

The results of the PAVT indicated

that changing the probability of hitting

a brine pocket has a negligible effect on

releases, but changing the brine volume

from 160,000 cubic meters to 17 million

cubic meters does have a noticeable

effect on releases for the scenarios in

which a brine pocket is hit.

Nevertheless, the PAVT results

indicated that, even with these changes

combined with other parameter

changes, the PAVT results are similar to

those in the CCA and still meet the

containment requirements by more than

one order of magnitude. EPA believes

that the PAVT verifies that the original

CCA Castile brine reservoir parameters

were adequate for use in PA and

comparison against the radioactive

waste containment requirements. See

the preamble for § 194.34(f) for

additional information on the results of

the PAVT.

EPA agrees with DOE’s conclusion in

the CCA that the most important

extractable resources near the WIPP are

hydrocarbons, potassium salts (potash),

and water. DOE indicated that some of

the geologic formations below the

repository area contain oil and gas

resources that are currently being

exploited in the Delaware Basin.

According to DOE’s analysis, most of

the water in the vicinity of the WIPP is

highly saline, with the closest

dependable potable aquifer associated

with the Capitan Reef at the edge of the

Basin. With respect to potash, the CCA

indicated that only the 4th and 10th

potash zones qualify as economic

reserves. Commenters noted that the

extent of potash identified by DOE is

different than that identified by the

Bureau of Land Management in its map

of resources. EPA concludes that DOE’s

presentation is reasonable, given the 40

CFR Part 194 requirements that DOE

assess resources relative to those

currently being mined.

The projected effect of waste on the

disposal system are primarily limited to

gas generation that increases repository

pressure and actinide solubility. Gas

will be generated: (1) By corrosion of

metals and (2) as a byproduct of

microbial degradation of cellulosics,

plastics and rubbers. Gas generation

primarily affects spallings (due to high

pressures) and direct brine releases (due

to high pressures and increasing

solubility). DOE indicated that

magnesium oxide (‘‘MgO’’) backfill

emplaced with transuranic waste would

mitigate the solubility-enhancing effects

of carbon dioxide from waste

degradation. EPA concurs with DOE’s

assessment. Refer to § 194.44 for further

discussion of the effects of MgO.

Although commenters questioned

DOE’s characterization of the WIPP site,

especially the hydrology, EPA

concluded after extensive review that

DOE identified, characterized, and used

in the calculations the major

components of the geologic and

hydrologic system around the WIPP.

DOE provided a detailed discussion of

the geology and identified the few

geologic units that are important to PA.

DOE also identified that very few

geologic units could transmit fluids and

transport radionuclides; after an

intrusion, only the Culebra dolomite is

a significant pathway above the Salado

with other overlying units not receiving

any contaminated brine. EPA reviewed

DOE’s discussion on dissolution and

karst and concludes that these processes

are not currently significant and will not

affect WIPP over the regulatory time

period. EPA disagreed with DOE’s

characterizations of the Castile brine

pocket and required changes for the

PAVT; however, PAVT results verified

that the original parameters were

acceptable for use in the PA.

B. Disposal System Design

Section 194.14(b) requires DOE to

describe the design of the disposal

system, including natural and manmade materials, and architectural and

structural aspects of the disposal

system. DOE also must describe the

computer codes and standards that have

been applied to the design and

construction of WIPP.

The CCA contained a general

description of the WIPP facility and a

detailed description of the underground

disposal system (including the

engineered barriers in the repository

and shaft system as well as the geologic

units). The WIPP repository is an

underground mine that will eventually

have eight panels (each of which will

include seven football-field long rooms)

connected by drifts. Waste will be

emplaced in the WIPP through the

waste shaft. An exhaust shaft, salt

handling shaft, and air intake shaft also

penetrate the WIPP repository. The

underground mine is attended by

surface equipment and buildings that

will handle waste prior to its

emplacement in the WIPP. DOE intends

to pack bags of magnesium oxide

(‘‘MgO’’) around the waste containers,

and will seal each panel after it is filled

with waste. The Salado salt will

eventually ‘‘creep’’ and close WIPP

rooms and panels. The WIPP was

designed to take advantage of this

encapsulation so that transuranic waste

emplaced in the WIPP will be

completely enveloped by salt, thus

minimizing the potential for waste

migration.

The major disposal system engineered

features related to long-term

performance are the general design,

shaft seals, panel closures, borehole

plugs, and the additional engineered

barrier of backfill around the waste. 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 disposal system 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, clay, compacted

salt, cementitious grout, and earthen fill.

DOE identified the compacted salt

column as the most critical element in

the long-term performance of the shaft

seal. The compacted salt column

component of the system within the

Salado is intended to serve as the
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primary long-term barrier by limiting

fluid transport along the shaft during

the 10,000-year regulatory period. The

other components of the shaft seal

within the Salado are intended to

prevent migration of radionuclides in

the short term and protect the

compacted salt column until it is

sufficiently consolidated to act as an

effective long-term barrier. Components

of the seal system within the Rustler are

intended to limit the commingling of

groundwater between the water bearing

members. The seal system overlying the

Rustler will consist of compacted

earthen fill. The shaft seal design in the

CCA received extensive technical

review by DOE, and was also subjected

to an independent design review. EPA

concludes that the shaft seal design is

adequate because the system can be

built and is expected to function as

intended.

The purpose of borehole plugs is to

mitigate the potential for migration of

contaminants toward the accessible

environment. DOE indicated that it will

abide by the applicable State oil and gas

well plugging requirements. While there

are four deep research wells drilled in

the disposal system, DOE stated that

‘‘the ERDA–9 exploratory hole was the

only hole within the underground

development area which was permitted

to penetrate the Salado formation to the

underground facility horizon.’’ ERDA–9

did not penetrate an area that will

become a waste panel and DOE has

indicated that abandoned boreholes

more than a meter away from the waste

can be screened out of PA due to low

consequence. EPA agrees with DOE’s

assessment that these boreholes are not

significant to performance of the

disposal system and can be screened out

of PA.

The primary long-term effect of the

panel closure will be to block the flow

of brine between panels. DOE provided

four design options for panel closures

but did not specify in the CCA which

panel closure option would be used at

WIPP, an omission that was pointed out

in public comments. (Docket A–93–02,

Item II–H–10) In reviewing the four

panel closure design options, EPA

identified Option D in the CCA as the

most robust design, and reviewed that

design as the basis for an evaluation of

compliance. EPA found that the design

for Option D would be expected to

perform as described, but that the use of

a Salado mass concrete (consistent with

the type specified for the shaft seal

system) rather than fresh water concrete

would be more consistent with the

permeability assumptions used in PA.

EPA determined that such a design is

adequate to achieve the long-term

performance modeled in PA, and

therefore proposes to find that DOE

complies with § 194.14(b). However,

because EPA is basing its proposed

compliance determination on the

Option D panel seal design, the EPA is

also proposing to establish a

certification condition requiring DOE to

implement the Option D design, with

Salado mass concrete replacing fresh

water concrete. (See Condition 1 in the

proposed Appendix A to 40 CFR Part

194.) Although EPA’s sensitivity

analysis indicates that the panel closure

permeability is not a sensitive

parameter, especially with the disturbed

rock zone at the same or higher

permeability, the Agency believes it is

important to ensure that the proposed

design on which compliance was based

is actually implemented at the site.

Because of the presence of the disturbed

rock zone, EPA expects that gas flow

between panels for long-term

performance purposes would be

relatively unaffected by the design

choice.

C. Results of Assessments

Section 194.14(c) requires the CCA to

present the results of assessments of the

WIPP’s performance, given human

intrusion into the disposal system

(performance assessment) and

undisturbed conditions (compliance

assessment). EPA determined that

DOE’s results showed compliance with

the containment (§ 191.13), individual

(§ 191.15), and ground water (40 CFR

Part 191, Subpart C) requirements of the

disposal regulations. Refer to

discussions of § 194.34 and § 194.55 for

EPA’s full evaluation of results of

assessments. Based on EPA’s finding

that information submitted by DOE was

sufficient for compliance with §§ 194.34

and 194.55, the Agency proposes to find

that DOE also complies with § 194.14(c).

D. Input Parameters to Performance

Assessments

40 CFR 194.14(d) requires DOE to

describe the input parameters to the PA

and discuss the basis for their selection.

DOE provided descriptions of input

parameters to the PA. EPA’s evaluation

of this information is addressed in the

discussion of § 194.23 of this preamble.

Based on EPA’s finding that information

was sufficient for compliance with

§ 194.23, the Agency proposes to find

that DOE also complies with

§ 194.14(d).

E. Assurance Requirements

Section 194.14(e) requires

documentation of measures taken to

meet the assurance requirements. EPA

considers DOE to have complied with

§ 194.14(e) if it provided the

information required for §§ 194.41

through 194.46. Based on EPA’s

determination of compliance for all six

assurance requirements (active

institutional controls, monitoring,

passive institutional control, engineered

barriers, consideration of the presence

of resources, and removal of waste),

EPA proposes to find that DOE also

complies with § 194.14(e).

F. Waste Acceptance Criteria

Section 194.14(f) requires DOE to

describe waste acceptance criteria and

the measures taken to assure adherence

to such criteria. EPA reviewed

documentation provided by DOE and

observed DOE audits and other

activities, and concluded that DOE

provided satisfactory descriptions of

actions that will be followed to ensure

adherence to the waste acceptance

criteria. EPA therefore proposes to find

DOE in compliance with § 194.14(f).

Refer the preamble discussion of

§ 194.24 for a complete discussion of

EPA’s review of waste acceptance

criteria and other waste characterization

information.

G. Background Radiation

40 CFR 194.14(g) requires DOE 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.

DOE provided information regarding the

levels of background radiation in air,

soil, surface water, sediments,

groundwater, and biota. DOE also

provided a description of the

procedures used to determine the

background radiation. DOE indicated

that background radiation in the vicinity

of the WIPP site is influenced by natural

sources of radiation, fallout from

nuclear tests, and one local research

project (Project Gnome, which involved

the underground detonation of a nuclear

device on December 10, 1961, at a site

approximately 8 miles (13 kilometers)

southwest of the WIPP site).

EPA found that DOE provided

sufficient discussion of background

radiation levels and associated

procedures to monitor these media for

radiation. EPA, therefore, proposes to

find that DOE complies with § 194.14(g).

H. Topographic Maps

40 CFR 194.14(h) requires DOE to

provide one or more topographic maps

of the vicinity of the disposal system. At

least one map must show boundaries of

the controlled area and the location of

active, inactive and abandoned injection

and withdrawal wells in the controlled

area and in the vicinity of the disposal
58802 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

system. The CCA must include

topographic maps with a contour

interval sufficient to show clearly the

pattern of surface water flow in the

vicinity of the disposal system.

DOE provided four topographic maps

that show the pattern of surface water

flow in the vicinity of the WIPP. The

CCA included three figures showing the

locations of the controlled area within

the U.S. Public Land Survey coordinate

system, as well as a map showing the

location of active, inactive, and

abandoned injection and withdrawal

wells in the controlled area and in the

vicinity of the disposal system. EPA

reviewed the topographic maps

provided in the CCA to determine their

sufficiency. EPA determined that DOE

met the requirements of § 194.14(h)

because it provided multiple,

appropriately scaled, topographic maps

of the vicinity of the disposal system.

I. Past and Current Meteorological

Conditions

40 CFR 194.14(i) requires DOE to

describe past and current climatologic

and meteorological conditions in the

vicinity of the disposal system. DOE is

also required to project how these

conditions are expected to change over

the regulatory time frame.

DOE described past glaciation events,

climatic changes, and precipitation and

temperature averages. DOE also

discussed how historical climatic

conditions were used to anticipate

climatic conditions 10,000 years in the

future. DOE described current climatic

conditions in the WIPP area, including

summaries of recent rainfall,

temperature, and wind data. DOE

discussed how climate changes were

incorporated in conceptual models.

Based on public comments and EPA’s

review of the CCA, EPA requested

additional information on dissolution.

Supplemental information submitted by

DOE addressed EPA’s concerns. EPA

concluded that the description of past

and present climatic changes and

associated impacts on the WIPP

disposal system were adequately

addressed, and therefore proposes to

find DOE in compliance with

§ 194.14(i).

J. Other Information Needed for

Demonstration of Compliance

40 CFR 194.14(j) requires DOE 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.

The preamble for other sections of the

Compliance Criteria discuss in greater

detail DOE’s responses to EPA’s formal

requests for additional information and

any other supplementary information

reviewed by EPA after October 29, 1996.

All documents sent to EPA are available

in the EPA docket. Additional

documentation that was not sent to EPA

but was reviewed by the Agency (e.g.,

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 III–B–1 for

further information on the location of all

documentation reviewed by EPA.

EPA determined that DOE responded

adequately to EPA’s formal requests for

additional information, analyses, and

records; and therefore proposes to find

that DOE complies with § 194.14(j).

K. Conclusion

Based on the information provided in

the CCA and additional information

submitted by DOE, EPA proposes that

DOE demonstrates compliance with all

subsections of § 194.14. For additional

information on EPA’s evaluation of

compliance for § 194.14, see CARD 14.

X. General Requirements

The general requirements of 40 CFR

Part 194, Subpart C, are intended to

ensure that any compliance certification

application (‘‘CCA’’) is based on

dependable and verifiable information

and that EPA has the right to confirm

the accuracy of such information.

Although they have no direct corollary

in the disposal regulations, EPA issued

these requirements in implementing the

disposal regulations because the Agency

believes that a reasonable expectation of

compliance with the containment

requirements (discussed in subsequent

portions of this preamble) can be

achieved only if the information and

methods used to conduct performance

assessments are valid and reliable. To

that end, the general requirements at

§§ 194.22 through 194.27 establish

requirements for quality assurance

programs, models and computer codes,

waste characterization, future state

assumptions, expert judgment, and peer

review.

A. Section 194.22, Quality Assurance

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

(including waste characterization

activities, environmental monitoring,

field measurements, computer codes,

procedures for expert elicitation,

disposal system designs, and data), (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 in the CCA, and (e) allow

verification of the above measures

through EPA inspections. The DOE’s

QA program must adhere to specific

Nuclear Quality Assurance (‘‘NQA’’)

standards and requirements issued by

the American Society of Mechanical

Engineers (‘‘ASME’’).

The EPA assessed compliance with

the QA requirements in two ways. First,

EPA reviewed QA information in the

CCA and associated reference

documents. EPA’s second level of

review consisted of visits to the WIPP

site, as well as WIPP-related facilities, to

perform audits and inspections to verify

DOE’s compliance with the QA

requirements. For example, 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. In this

way, EPA was able to review

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–
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15NQA–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 or 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.’’

1989 edition (excluding Section 2.1 (b)

and (c), and Section 17.1). DOE

incorporated these requirements in the

Quality Assurance Program Document

(‘‘QAPD’’) contained in the CCA. The

QAPD is the documented plan for the

WIPP project, as a whole, to comply

with the NQA requirements; it applies

to all activities and items important to

containment of waste in the WIPP. The

QAPD addresses the 18 basic

requirements of NQA–1, including

supplemental requirements as

established by NQA–1; the computer

software requirements as established by

NQA–2a, part 2.7; and the collection of

scientific and technical information

requirements for site characterization of

high level nuclear waste repositories as

established by NQA–3. The QAPD is

implemented by DOE’s CAO, which

provides overall coordination of WIPP

activities and has 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 conform to the QAPD. EPA

audited DOE’s QA program at CAO and

determined that DOE properly adhered

to a QA program that implements the

NQA standards and requirements.

Therefore, EPA proposes to find DOE in

compliance with § 194.22(a)(1). (For

information on the incorporation of

NQA requirements into lower tier

program plans, refer to the subsequent

discussion of § 194.22(a)(2), which

addresses specific activities under the

direct control of organizations other

than DOE’s CAO.)

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 and referenced criteria for the

review and approval of a site-specific

Quality Assurance Project Plan

(‘‘QAPjP’’) to address technical criteria

and implementation procedures. The

CCA listed five waste generator site

QAPjPs that have been approved by

DOE. DOE proposed that sites also will

prepare site certification Quality

Assurance Plans (‘‘QAPs’’) that, together

with the QAPjPs, are intended to

establish all the NQA requirements

applicable to waste characterization.15

EPA finds that the QAPD, as it applies

to waste characterization, is in

conformance with the NQA

requirements. As discussed below, the

Agency intends to verify the adequacy

of site-specific QA programs in the

future.

Another important activity related to

waste characterization is the ability to

track waste shipped to and emplaced in

the WIPP. The WIPP Waste Information

System (‘‘WWIS’’) is a computer

database and reporting program that

will track and tally the waste that comes

to the WIPP. The WWIS is covered by

QA programs both at the WID and at

waste generator sites. At Westinghouse,

the WID QAPD, which addresses the

specific requirements of the NQA

standards, governs operation of the

system. In September 1997, EPA

performed an inspection of the WID QA

program applicable to the WWIS. At

that time, the WWIS was demonstrated

to be operational, and EPA determined

that a QA program had been properly

executed for the WWIS in accordance

with the applicable NQA requirements.

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 waste characterization

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 (QAPs and, where applicable,

QAPjPs) and programs.

To date, one WIPP waste generator

site, Los Alamos National Laboratory

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

have established adequate QA programs

(encompassed in a QAP and QAPjP) and

to have properly executed QA

procedures in accordance with the

applicable NQA requirements. 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. 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.

Therefore, EPA proposes to find that the

requirements of § 194.22(a)(2)(i) have

been met for the WID QAPD, the WWIS,

and waste characterization activities at

LANL.

With respect to other waste generator

sites, EPA proposes to certify

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

subsequent to LANL establish QA

programs, EPA will assess their

compliance with NQA requirements. In

making any determination to approve a

site-specific QA program for a waste

generator, EPA will conduct an audit or

an inspection of a DOE audit of a waste

generator site. EPA will publish a notice

in the Federal Register announcing its

scheduled audit or inspection of a DOE

audit and will provide at least a 30-day

comment period during which

interested parties may submit written

comments. EPA will place in the docket

copies of the site-specific QA program

documents and other documentation

relevant to the audit or audit inspection.

Thus, the Agency’s decision whether to

approve the establishment and

execution of a QA program at a specific

waste generator site will be informed by

both public comments and the results of

the Agency’s own independent

evaluation of the site’s compliance with

the applicable NQA requirements.

EPA believes that approval of site

specific QA programs is required by,

and that this proposed procedure is

consistent with the provisions of

§ 194.22(a)(2)(i) because it requires DOE

to demonstrate ‘‘establishment and

execution’’ of quality assurance

programs for waste characterization

assumptions and activities at the

individual waste generator sites prior to

shipment of wastes from such sites. EPA

requests comment on whether the

Agency should place a condition on its

certification of compliance at WIPP

consisting of future demonstrations by

DOE that QA programs have been

established and executed at individual

waste generator sites, prior to shipment

of TRU waste to WIPP from such sites.

In particular, EPA requests comment on
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its preliminary conclusion that the

proposed procedures for determining

whether adequate quality assurance

programs have been established and

executed by DOE are consistent with

Part 194. However, if, based upon

public comment on today’s proposed

action, EPA concludes that it would be

appropriate to make clarifying changes

to Part 194 that specifically set forth

these procedures, EPA may do so as part

of its final action on today’s proposal.

EPA will indicate its approval of sitespecific QA programs by a letter from

the Administrator’s authorized

representative to the Department; a copy

of the letter will be placed in EPA’s

public docket. (As part of the

certification rulemaking, EPA is

proposing to define the Administrator’s

authorized representative as the

‘‘director in charge of radiation

programs at the Agency,’’ in order to

clarify the delegation of responsibilities

for 40 CFR Part 194, including activities

such as requesting additional

information from DOE, and inspecting

and approving quality assurance

programs.) After approval of sitespecific QA programs, EPA will exercise

its authority under §§ 194.21 and

194.22(e) to conduct unfettered

inspections of approved waste generator

sites to confirm that the approved plans

are being properly maintained for waste

characterization activities. For specific

language on the quality assurance

conditions of compliance, see Condition

2 of the proposed Appendix A to 40

CFR Part 194. For further discussion of

waste characterization programs and

certification of individual waste streams

from generator sites, see the discussion

of § 194.24 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

implementing this requirement under

the WID QAPD described in the CCA.

The WID developed a WIPP

Environmental Monitoring Plan

(‘‘EMP’’), which applies to current site

characterization and also to proposed

pre-closure monitoring in accordance

with § 194.42. The EMP included QA

procedures for radiological and nonradiological environmental monitoring.

Also included in the EMP were sample

handling, laboratory procedures,

required records and reports, and data

analyses guidelines. DOE stated that the

EMP is consistent with applicable

elements of ASME NQA–1.

The EPA determined during its audit

of WID that the requisite QA program

had been established and executed for

environmental monitoring, sampling

and analysis activities. Therefore, EPA

proposes to certify compliance with

§ 194.22(a)(2)(ii). Continued adherence

to the executed QA program as it

applies to disposal system monitoring

will be confirmed by EPA in future

inspections under its authority at

§§ 194.21 and 194.22(e).

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,

groundwater, meteorologic, and

topographic characteristics. EPA

conducted an audit of the WID QA

program and found the QAPD to be

adequate and to be implemented in

accordance with the applicable NQA

requirements. Therefore, EPA proposes

to find DOE in compliance with

§ 194.22(a)(2)(iii).

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. In the CCA, DOE provided

the CAO QAPD, which incorporates the

application NQA requirements for

computation and computer code

information. Software development and

management are controlled in

accordance with criteria established by

SNL software QA procedures and the

WID QAPD. EPA reviewed information

in the CCA and conducted audits of

both SNL and WID QA programs. The

Agency found that DOE’s computer

codes were documented in a manner

that complies with the applicable NQA

requirements, and that DOE’s software

QA procedures were implemented in

accordance with ASME NQA–2a, part

2.7. EPA therefore proposes to

determine 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. EPA found that the

requirements of this regulation were met

with the implementation of CAO Team

Procedure (‘‘TP’’) 10.6 (Revision 0),

CAO Team Plan for Expert Panel

Elicitation (Revision 2), and CAO

Technical Assistance Contractor

(‘‘CTAC’’) Experimental Programs

Desktop Instruction No.1 (Revision 1).

EPA proposes to find DOE in

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

process of expert judgment elicitation is

discussed in further detail in the

preamble for § 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. Design work

for the repository sealing system was

conducted under the SNL QA program.

The repository seal system design was

extensively reviewed by DOE, SNL,

WID, and CAO Technical Assistance

Contractor personnel, as well as

independent design reviewers. 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. EPA audits of SNL and

WID showed that the QA programs are

adequate and properly executed.

Therefore, EPA proposes to find 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 adequately addressed these

requirements by implementing

numerous QA procedures to ensure the

quality of data and information

collected in support of the WIPP. EPA’s

audit of SNL concluded that the QA

program was adequate and

appropriately implemented. Therefore,

EPA proposes to find 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. 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. EPA has also not

identified to date any other items or

activities which require controls.

However, EPA has reviewed the CAO

QAPD and conducted audits of the

CAO, SNL, and WID QA programs. 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 proposes to find DOE in

compliance with § 194.22(a)(2)(viii).
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58805

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

CCA listed existing data that were

reviewed by an Independent Review

Team and that DOE determined to have

been collected under a QA program

equivalent to the NQA standards. DOE

also provided information on NUREG–

1297 peer reviews that were conducted

to qualify existing data for engineered

systems, natural barriers, waste form,

and disposal room data. Finally, DOE

identified data from literature sources.

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.

EPA also concluded that the use of

existing data from peer-reviewed

technical journals was appropriate,

since the level of such reviews was

likely to provide QA equivalent to

NUREG–1297 peer reviews conducted

by DOE. Therefore, EPA proposes to

find DOE in compliance with

§ 194.22(b). Furthermore, the Agency is

proposing to approve 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

parameters, but asserted that the intent

of DQCs was fulfilled by other QA

programs and quality control measures.

In response to EPA’s request for

additional information, DOE clarified

but did not substantially alter its

approach. (Docket A–93–02, Items II–I–

17 and II–I–24)

The Agency agrees that it is not

appropriate to apply DQCs to

parameters in the PA (e.g., anhydrite

permeability parameter), but believes

that they can be applied to measured

data (i.e., field monitoring and

laboratory experiments) on which

parameter values are based. Because

DOE misinterpreted EPA’s requirements

as applying to parameters, EPA found

that the CCA and supplementary

information did not systematically or

adequately address DOE’s consideration

of DQCs for measured data. Therefore,

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 PA.

Data record packages document

measured data considered by DOE in

developing parameter values. 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

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 compliance application; EPA

concluded that the peer review panels

considered the use of DQCs in

determining that such data were

adequate. 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).

Based on its review of data record

packages, the Agency finds that DOE

has assessed DQCs, to the extent

practicable, for data used in the

compliance application. EPA thus

proposes to find that DOE complies

with § 194.22(c). The Agency expects

that DOE will assess DQCs for future

waste characterization and monitoring

activities; EPA will confirm assessment

of DQCs for such measured data through

inspections and evaluation of any

compliance re-certification applications.

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.

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

proposes to find 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 plans to conduct additional

inspections, including audits, of CAO,

SNL, and WID prior to publishing a

final certification decision. The purpose

of these inspections will be to verify

that the QA programs for these

organizations—which have already been

found to be properly executed in

accordance with the applicable NQA

requirements—are being appropriately

maintained. EPA will docket the results

of these inspections, but will not

consider them for the purpose of the

proposed or final rule unless the

inspections result in new information

that indicates that the programs are no

longer in conformance with the

applicable NQA requirements.

In summary, EPA proposes to find

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.) For further information on EPA’s

evaluation of compliance for § 194.22,

refer to CARD 22.

B. Section 194.23, Models and

Computer Codes

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
58806 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

16 ‘‘Spallings’’ refers to releases of solids forced

up and out of an intrusion borehole by gas pressure

in the repository.

the PA. Design of computer codes

begins with the development of

conceptual models. Conceptual models

consider the design of the repository

and the features, events, processes, and

scenarios that may occur at the WIPP

which could affect the containment or

release of radionuclides. In order for the

final computer codes to obtain realistic

solutions, the underlying conceptual

models must be sound. DOE must next

develop mathematical models from the

conceptual models. Mathematical

models set up a mathematical

expression to describe the conditions in

the repository and its surroundings.

Numerical models are then created to

describe how to solve the equations in

the mathematical models. Since most of

the mathematical models are

sufficiently complex that analytical

solutions are not possible, numerical

models are used to provide iterative,

approximate solutions to the

mathematical models. Finally, DOE

must program the numerical solutions

from the numerical models into

computer codes that perform

calculations to estimate the cumulative

releases of radionuclides caused by all

significant processes and events.

In examining models and computer

codes, EPA evaluated the development

of the underlying conceptual models,

evaluated the derivation of

mathematical models and

implementation of numerical models

and computer codes, verified the quality

assurance of computer codes, and

performed its own independent

computer calculations. In order to allow

EPA to evaluate the underlying

conceptual models, § 194.23 of the

compliance criteria requires

descriptions of conceptual models and

scenario construction (§ 194.23(a)(1)),

consideration of alternative conceptual

models (§ 194.23(a)(2)), and

documentation of peer review of the

conceptual models (§ 194.23(a)(3)(v)).

To ensure proper implementation of

these conceptual models, § 194.23 also

requires documentation that: future

states of the disposal system are

reasonably represented by conceptual

models (§ 194.23(a)(3)(i)); mathematical

models (or algorithms) reasonably

represent the conceptual models

(§ 194.23(a)(3)(ii)); numerical models (or

solution methods) provide stable

solutions to the mathematical models

(§ 194.23(a)(3)(iii)); and computer codes

accurately implement the numerical

models and are free from coding errors

and produce stable solutions

(§ 194.23(a)(3)(iv)). In addition, DOE

must describe the theoretical

background of models and their method

of analysis; how the computer codes

operate and were developed; methods of

data collection, data reduction and

analysis; parameters developed from

source data; the structure of the

computer codes and a complete listing

of source codes; and the effects of

parameter correlation (§§ 194.23(c)(1)

through (6)). Section 194.23(b) requires

DOE to document that models and

computer codes were developed in

accordance with the specified QA

requirements contained in the ASME

NQA standards. Finally, § 194.23(d)

requires DOE to provide all necessary

data, information, software, and any

other material to enable EPA to conduct

its own independent computer

simulations.

1. Conceptual Models

a. Description of Conceptual Models.

Section 194.23(a)(1) requires the CCA to

describe the conceptual models and the

scenarios used in the CCA PA

calculations. DOE developed 24

conceptual models to describe the WIPP

disposal system. DOE also undertook an

extensive screening process to

determine which features, events, and

processes (FEPs) were applicable to the

disposal system. From the list of

applicable FEPs, DOE developed

scenarios to describe both undisturbed

performance (natural processes and

events) and disturbed performance

(human intrusion, including mining and

deep drilling) of the repository. The

CCA included scenarios that satisfy the

specific requirements of §§ 194.32 and

194.33 concerning the scope of PA and

consideration of drilling events in PA.

(See preamble discussions of §§ 194.32

and 194.33 for further details.)

EPA reviewed the descriptions of the

24 conceptual models and the scenario

construction methods in the CCA and

supplementary information and found

them to be presented with sufficient

clarity to permit full understanding of

the descriptions and methods. However,

both EPA and public commenters 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, EPA required DOE to

perform additional analyses of fluid

injection. Based on supplementary

information provided by DOE, EPA

concluded that fluid injection can be

screened out from the PA based upon

low consequences to disposal system

performance. EPA and commenters also

had concerns about DOE’s conceptual

model for spallings.16 The results of the

spallings model were eventually

determined to be reasonable and

adequate for use in PA. For further

discussion of the spallings model, refer

to the discussion of models and

computer codes later in this section.

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

conceptual models include those

characteristics and attributes of the

WIPP disposal system and its

surroundings that adequately describe

the possible future performance of the

disposal system. The conceptual models

contain appropriate simplifications of

the characteristics, attributes, and

processes of the disposal system. 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 its review of DOE’s descriptions of

the conceptual models and the scenario

construction procedures presented in

the CCA and supporting documents, the

Agency proposes to determine that the

DOE has demonstrated compliance with

the requirements of § 194.23(a)(1).

b. Alternative Conceptual Models.

Section 194.23(a)(2) requires the CCA to

describe plausible, alternative

conceptual models that DOE seriously

considered but did not use to support

compliance, and to explain why DOE

decided the alternative conceptual

model does not accurately portray

performance of the disposal system.

This requirement allows EPA to

evaluate whether the conceptual models

underlying the PA and compliance

assessment are appropriate and

adequate.

DOE provided information on

alternative conceptual models in the

CCA, both in its discussion of FEPs and

in its documentation of the conceptual

models peer review panel. The peer

review panel identified no major issues

concerning alternative models.

EPA reviewed information on

alternative conceptual models in the

CCA and in documentation from the

peer review panel. EPA requested, and

DOE provided, supplementary

information containing a focused,

detailed description of plausible

alternative conceptual models

considered but not used in the PA. DOE

also explained the reasons why these

alternative models were not used to
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58807

describe the performance of the

repository. EPA determined that DOE

sufficiently documented the rationale

and approach used to select the

conceptual models employed in the

CCA PA and to reject other models. As discussed elsewhere in this

section, the conceptual models peer

review panel and EPA had concerns

specifically with the spallings

conceptual model. Because the

conceptual models peer review panel

initially judged the spallings model

used in the CCA to be inadequate, DOE

developed an alternative

mechanistically-based computational

approach to estimate the volume of

spallings released to the accessible

environment. The volumes of

radioactive waste to be released that

were calculated by the alternative

mechanistically-based model were less

than one tenth those predicted in the

model used in the CCA. Because the

original spallings model results used in

the CCA were conservative, the

conceptual models peer review panel

and EPA found the predicted results

from the original model to be acceptable

for use in the PA.

Based on information provided in the

CCA together with supplementary

information provided by DOE in

response to specific EPA requests, EPA

concluded that DOE provided an

adequate and complete description of

alternative conceptual models seriously

considered but not used in the CCA.

DOE provided adequate discussion of

why these alternative models were not

deemed to adequately portray the

performance of the disposal system.

Therefore, EPA proposes to find DOE in

compliance with § 194.23(a)(2).

c. Future States of the Disposal

System and Peer Review. Section

194.23(a)(3)(i) requires the CCA

conceptual models and scenarios to

reasonably represent future states of the

disposal system. Section 194.23(a)(3)(v)

requires the CCA to document that

conceptual models have undergone peer

review in accordance with § 194.27,

which requires that the peer review

meets the guidance of NUREG–1297.

Under this guidance, the peer review

must include the following: A listing of

the reviewers; requirements for the

acceptability of each reviewer;

individual statements by peer reviewers

reflecting dissenting views, if any; a

discussion of the conceptual models

peer reviewed; an evaluation of data and

information used to develop conceptual

models; an evaluation of the validity of

conceptual model assumptions; an

evaluation of alternative conceptual

models; an evaluation of the uncertainty

in the conceptual models and a

discussion of consequences if the

conceptual model chosen is

inappropriate for the site; a statement

indicating the adequacy of the

conceptual models used for the disposal

system; a statement of the accuracy of

the results based on the conceptual

models employed; and a discussion of

the validity of the conclusions drawn

based on the conceptual models. As part

of the review of adequacy of the

conceptual models, peer reviewers

considered whether conceptual models

reasonably represented future states of

the disposal system. The NUREG–1297

requirements and the process of peer

review are discussed in greater detail in

the preamble for § 194.27.

DOE convened a conceptual models

peer review panel to review the 24

conceptual models used in the CCA PA.

During the initial review, the panel

found that 11 models were not adequate

and 13 models were adequate for use in

PA. The panel initially found the 11

conceptual models to be inadequate for

a variety of reasons, mostly related to

the adequacy of assumptions

incorporated in the conceptual models

and the amount of supporting data or

analyses for certain features of the

conceptual models. Based on additional

information provided by DOE and three

subsequent review sessions, the panel

found all the models to be adequate for

use in PA except the spallings model.

They found that the original CCA PA

spallings model did not reasonably

represent possible future states of the

disposal system because it did not fully

model all potential mechanisms that

may cause pressure-driven solid

releases. The panel ultimately

concluded, based on substantial

analytical and experimental work

provided by DOE, that the spallings

values used in the CCA are reasonable

for use in PA. The panel found that,

while the spallings model does not

accurately represent the future state of

the disposal system, its inaccuracies are

of an overly conservative nature, and in

fact, may overestimate the actual waste

volumes that would be expected to be

released by the spallings process.

EPA concurs with the conceptual

model peer review panel’s findings,

based upon the results of DOE’s analysis

and development of an alternative

model for spallings, which showed that

the CCA PA spallings model

overestimates spallings releases by up to

ten times or more. The peer review

panel’s findings considered whether

conceptual models reasonably

represented future states of the disposal

system. EPA does not propose to

determine that the spallings model

‘‘reasonably represents possible future

states of the repository.’’ The additional

modeling conducted by DOE, and the

additional data developed by DOE,

however, 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.

Because the spallings model produces

reasonable and conservative results,

EPA proposes to accept it for purposes

of demonstrating compliance with

§ 194.23(a)(3)(i).

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.

Therefore, the Agency proposes to find

that DOE has demonstrated compliance

with the requirements of

§ 194.23(a)(3)(v).

d. Public Comments. During the

public comment period on the Advance

Notice of Proposed Rulemaking

(‘‘ANPR’’), EPA received numerous

comments challenging various aspects

of the spallings model. EPA and the

conceptual models peer review panel,

among others, shared concerns about

the adequacy of the spallings model and

on numerous occasions informed DOE

of their concerns. In response to these

concerns, DOE did substantial

additional work, developed a

mechanistically-based model and

supported this model with 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. On this basis, and as

discussed above, EPA proposes that it is

appropriate to accept the results from

the spallings model for purposes of

demonstrating compliance with

§ 194.23(a)(3)(i).

EPA also received public comments

on the ANPR concerning modeling of

fluid injection. Commenters expressed

concern that the CCA PA calculations

did not model possible effects of

pressurized brine injection that may

fracture the anhydrite beds near WIPP,

enter the repository, become

contaminated and flow to various

release points. EPA required DOE to

perform extensive supplementary

analyses to evaluate the effects that

brine injection could have on the

repository. EPA also performed

independent analyses to address

concerns related to brine injection. EPA

has determined that brine injection does

not pose an unacceptable risk and that

associated scenarios can be reliably

screened from further consideration.
58808 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

17A functional requirement specifies how the

code is intended to operate, including inputs and

outputs.

2. Progression From Conceptual Models

to Computer Codes

Most of the requirements of

§ 194.23(a)(3) concern the Agency’s

evaluation of the progression from

conceptual models to computer codes

used in the CCA PA and compliance

assessment. Each requirement in

§§ 194.23(a)(3)(i) through (iv) is

intended to ensure that DOE has

correctly implemented the steps

between development of the underlying

conceptual models and encoding the

computer software that implements the

PA and compliance assessment

calculations. The initial step of

evaluating the fundamental conceptual

models is discussed above.

a. Mathematical Models. Section

194.23(a)(3)(ii) requires the CCA to

document that mathematical models

incorporate equations and boundary

conditions which reasonably represent

the mathematical formulation of the

conceptual models. This requirement is

intended to ensure that PA calculations

are based upon mathematical equations

that truly implement the conditions in

the fundamental conceptual models.

Many of the mathematical equations are

partial differential equations, which

consider rates of change; thus, codes

incorporating these mathematical

models need initial and boundary

conditions between which the rates of

change in the equations will operate.

DOE documented the development of

each computer code used in PA and

compliance assessment, including the

associated mathematical models and

numerical models. This information was

contained primarily in Users Manuals,

Validation Documents, Implementation

Documents, and Requirements

Document & Verification and Validation

Plans for each CCA PA computer code.

EPA reviewed information

supplemental to the CCA for each CCA

PA computer code and evaluated

whether the mathematical models

incorporate equations and boundary

conditions which reasonably represent

the mathematical formulation of the

conceptual models.

EPA reviewed the mathematical

model equations and boundary

conditions for the following codes:

PANEL, BRAGFLO, NUTS, FMT,

SANTOS, BRAGFLOlDBR, GRASP–

INV, SECOFL2D, SECOTP2D, CCDFGF,

and CUTTINGSlS. These are the codes

DOE used to model the behavior of the

repository and its surroundings and to

compute results of the PA calculations.

The codes PANEL, BRAGFLO, NUTS,

FMT, and SANTOS incorporate

mathematical model equations that

implement the conceptual models for

predicting future characteristics of the

waste repository. These five codes

simulate the following effects,

respectively: concentrations of

radioactive waste in brine within the

waste-containing panels in the

repository; flow of brine and gas in the

repository; solubility and transport of

radionuclides released from the

repository; solubility of radionuclides in

the repository; and collapse of the

repository through salt creep closure of

the Salado. The computer code

BRAGFLOlDBR describes waste

dissolution in brine and transport of the

contaminated brine through direct brine

releases. The three computer codes

GRASP–INV, SECOFL2D, and

SECOTP2D mathematically describe

flow and transport of waste-laden brine

in the Culebra dolomite. The computer

code CUTTINGSlS incorporates

mathematical model equations

modeling releases of radioactive waste

upon intrusion of a drill bit into the

repository. The computer code CCDFGF

computes complementary cumulative

distribution functions (‘‘CCDFs’’) for the

results of PA.

In general, EPA found that the

descriptions of mathematical

formulations were adequately explained

and were reasonable. The Agency found

that DOE adequately documented and

described simplifications of conceptual

models in the CCA. EPA also concluded

that DOE provided an adequate

technical basis to support the

mathematical formulations. EPA tested

each of the codes with functional tests

to verify that each computer code would

perform according to its functional

requirements.17 This analysis and

testing indicated that equations and

boundary conditions were properly

incorporated into the mathematical

models and that boundary conditions

were reasonable representations of how

the conceptual models should be

implemented.

EPA encountered problems with the

governing equations of the mathematical

models and the representation of the

boundary conditions in the codes

CUTTINGSlS, SECOFL2D, SECOTP2D,

NUTS and BRAGFLO. EPA specified

that the equations in the codes be

corrected and that the changes to the

codes be documented. 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 necessary corrections to

input parameters, conceptual models,

and computer codes used in PA was not

significant enough to necessitate a new

PA. For the PAVT, DOE used corrected

versions of the BRAGFLO, NUTS and

SECOTP2D computer codes. The results

of the PAVT demonstrate that the

cumulative impact of all these necessary

corrections did not require new PA

runs. DOE resolved all of EPA’s

questions related to the equations that

make up the mathematical models and

the incorporation of the boundary

conditions of the various codes by

correcting the codes and performing the

PAVT.

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. DOE resolved all

issues raised by the Agency. DOE has

provided an adequate technical basis to

support the mathematical formulations

used in the PA. Therefore, the Agency

proposes to find DOE in compliance

with § 194.23(a)(3)(ii).

b. Public Comments on Mathematical

Models. During the public comment

period on the ANPR, EPA received

comments on aspects of the

mathematical models. Several

commenters felt that the mathematical

models in the CCA PA, particularly

those related to ground-water flow in

the Culebra dolomite, did not account

sufficiently for three-dimensional

processes and boundary conditions. A

DOE report provided a detailed

sensitivity analysis of ground-water

flow characteristics in the Culebra. This

report concluded that the majority of

ground-water flow through the Culebra

is horizontal. (Docket A–93–02, Item II–

G–1, Reference #147) From the

perspective of calculating the potential

consequences to repository

performance, neglecting vertical leakage

into and out of the Culebra is

conservative. EPA believes that the twodimensional modeling approach used in

the PA for ground-water flow in the

Culebra dolomite is conservative and

adequate. EPA also reviewed the FEP

screening analysis related to flow of

brine and gas in the repository and

concluded that there are only minor

differences between the twodimensional and three-dimensional

computations. Therefore, EPA believes

that the two-dimensional geometry used

in the BRAGFLO computer code is

reasonable and appropriate for the CCA

PA.

EPA also received public comments

on the ANPR concerning the modeling
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58809

of ground-water flow and radionuclide

transport processes in the Culebra.

Commenters stressed that scientific

understanding of ground-water flow in

fractured rock systems is still

developing and that DOE requires

greater documentation of processes and

parameters embodied in the CCA PA.

EPA notes in response to public

comments that DOE conducted an

extensive investigative program to

improve its theories of ground-water

flow and radionuclide transport through

the Culebra. Although these activities

have greatly improved the

understanding of the geohydrologic

system, EPA recognizes that a degree of

uncertainty will always exist when

attempting to make predictions about

the performance of WIPP 10,000 years

into the future. EPA required DOE to

address this uncertainty in its PA by

assigning ranges and distributions to

uncertain variables, such as fracture

spacings, distribution coefficients,

porosities and transmissivity. EPA also

required DOE to perform further

analysis using different parameter

values and distributions in the PAVT.

EPA believes that this approach to

handling uncertainty is appropriate

because the uncertainty will be captured

by the ranges and distributions assigned

to parameters.

c. Numerical Models. Section

194.23(a)(3)(iii) requires documentation

that numerical models provide

numerical schemes which enable the

mathematical models to obtain stable

solutions. Although some mathematical

models can be solved directly, many of

the mathematical equations used in PA

for the WIPP are so complex that they

require the use of numerical solution

methods to provide an approximate

solution. It is important that solutions to

the mathematical models be stable

because unstable solutions may make it

impossible to proceed to the next step

in obtaining PA results or may call into

question the results of the model.

The relevant information was

contained in supplemental information

from DOE, including Analysis Packages

for each code and the documents

described in the previous section. This

documentation includes testing results

for problems that are very similar to

those solved by the code(s) in the CCA

PA, in order to evaluate the stability of

solutions from the numerical schemes

used to solve the mathematical model

equations. DOE also maintained a

computational record of whether any of

the codes experienced stability

problems during the CCA PA

calculations. The codes that use

numerical solvers include: SANTOS,

CUTTINGSlS, SECOFL2D, SECOTP2D,

PANEL, BRAGFLO, BRAGFLOlDBR,

NUTS, and GRASP–INV.

EPA reviewed all the relevant

documentation on numerical solution

schemes contained in the CCA and

supplementary information about each

code. EPA also executed DOE code

verification tests to search for possible

stability problems. EPA’s review

identified stability concerns related to

the following codes: CUTTINGSlS,

SECOFL2D, SECOTP2D, and NUTS. In

the case of the NUTS and SECOTP2D

codes, DOE was able to make minor

changes to the codes to correct their

stability problems. EPA’s concerns

regarding potential stability problems

with CUTTINGSlS and SECOFL2D

were alleviated after DOE provided

results from further stability and code

verification testing that showed these

problems had been corrected. DOE

satisfactorily resolved all EPA concerns

regarding code stability issues.

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 determined that the numerical

models produced stable solutions. DOE

resolved stability problems with the

BRAGFLO, NUTS, SECOFL2D and

SECOTP2D computer codes by

completing code revisions and

supplementary testing requested by the

Agency. Therefore, EPA proposes to

find DOE in compliance with

§ 194.23(a)(3)(iii).

d. Computer Codes. Section

194.23(a)(3)(iv) requires documentation

that computer models accurately

implement the numerical models, such

that computer codes are free of coding

errors and produce stable solutions.

This is the final step to ensure that the

underlying conceptual models are

implemented correctly in the PA

calculations and to ensure that the PA

calculations will yield valid results.

To ensure that PA computer codes

accurately implement the numerical

models and are free of coding errors,

DOE adopted a number of Quality

Assurance Procedures for each step in

the software development process. (See

also the preamble discussions of

§§ 194.22 and 194.23(b).) DOE

documented information on the

software development process in Users

Manuals, Validation Documents,

Implementation Documents and

Requirements Document & Verification

and Validation Plans for each computer

code.

EPA performed an independent

review of the CCA PA computer codes

used to support the PA. As part of this

review, EPA executed functional tests

established by DOE for each of the codes

to verify that each computer code

performed according to its functional

requirements, and to verify that the

computer codes accurately implemented

the numerical models, were free of

coding errors, and produced stable

solutions. The codes that EPA reviewed

and tested include: SANTOS,

CUTTINGSlS, SECOFL2D, SECOTP2D,

CCDFGF, LHS, PANEL, BRAGFLO,

BRAGFLOlDBR, FMT, NUTS, GRASP–

INV and ALGEBRA. EPA also reviewed

all of the relevant documentation

pertaining to each of the major codes

described above.

EPA identified issues related to

coding errors for the following codes:

SECOFL2D, SECOTP2D, and NUTS. To

address these concerns, EPA requested

that DOE perform a number of

additional analyses. In the process of

responding to EPA’s concerns, DOE

discovered, rectified and documented

several minor coding errors. Results

from an impact analysis by DOE

indicated that the coding errors would

have very little impact on the WIPP’s

compliance with the disposal

regulations. These issues were resolved

to EPA’s satisfaction.

Based on the CCA and supplementary

information, the Agency determined

that DOE provided sufficient technical

information to document the numerical

models used in the CCA. Based on

verification testing, EPA determined

that the computer codes accurately

implement the numerical models and

that the computer codes are free of

coding errors and produce stable

solutions. DOE resolved coding error

problems that EPA initially encountered

by performing code revisions and

supplementary testing requested by the

Agency. Therefore, the Agency proposes

to conclude that DOE has demonstrated

compliance with § 194.23(a)(3)(iv).

3. Quality Assurance

Section 194.23(b) requires that

computer codes used in the CCA must

be documented in a manner that

complies with the quality assurance

requirements of ASME NQA–2a–1990

addenda, part 2.7, to ASME NQA–2–

1989 edition. This requirement is

intended to ensure proper development

and documentation of software and to

identify any potential problems. Based

on EPA audits and CCA review, EPA

found that code documentation meets

the NQA requirements, and thus

proposes to find that DOE complies

with § 194.23(b). See the preamble

discussion of § 194.22(a)(2)(iv), Quality

assurance, for further discussion of

EPA’s evaluation of compliance.
58810 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

18 ‘‘Source code’’ means the written description of

each step the computer code will follow when it is

executed.

19LHS, or Latin Hypercube Sampling, is a code

that selects or ‘‘samples’’ a numerical value from a

distribution of probable values for a parameter. For

more information on LHS, see the preamble

discussion of the requirements of § 194.34.

20The ALGEBRA computer code manipulates

input data and initial conditions that allow other

codes to perform their calculations.

21 Verification, bench marking and validation are

steps in testing computer codes to ensure they

operate as intended. Verification means that the

aspect of the code being tested matches known

solutions. Bench marking means that solutions from

the code are compared to results from an outside

reference or ‘‘bench mark’’ calculation, for more

complicated situations where the solutions to a

problem may not be known exactly. Validation

means all aspects of the code work together

properly.

4. Documentation of Models and Codes

Sections 194.23(c)(1) through (6)

contains a number of requirements

related to documentation of models and

computer codes. These requirements

allow EPA to evaluate the design of the

models, to evaluate the numerical

values selected to describe the

repository and its surroundings, and to

operate the software used to perform the

PA calculations.

DOE documented the development of

computer software in a series of

documents that supplement the CCA.

The information that EPA reviewed was

contained primarily in Analysis

Packages, User’s Manuals, Validation

Documents, Implementation Documents

and Requirements Document &

Verification and Validation Plans for

each code. DOE used these documents

to track development of software codes

beginning from the conceptual model

stage, and continuing through

derivation of the mathematical

equations and their solutions, setting

computational requirements for

computer codes, designing the computer

software, programming the software,

and testing the codes after they are

programmed. Among the types of

information found in these documents

are general descriptions of the models,

descriptions of the theoretical

background of models, discussions of

the limits of the models, instructions for

executing computer codes, information

on the required input and output

formats with examples, reports on

testing of the computer codes, structure

of the computer codes, source codes,18

and sources of data used to support

parameter values used in the models

and codes.

a. Theoretical Background. Section

194.23(c)(1) requires the CCA to

describe the theoretical backgrounds of

each model and the method of analysis

or assessment used by each model. EPA

evaluated whether DOE’s descriptions

of the computer codes provided

sufficient detail to determine if the

codes are formulated on a sound

theoretical foundation, and whether

DOE provided clear documentation

describing exactly how each of the

codes was used to support the PA. The

codes that EPA reviewed include:

CUTTINGSlS, SECOFL2D, SECOTP2D,

CCDFGF, LHS,19 PANEL, BRAGFLO,

BRAGFLOlDBR, NUTS, FMT, GRASP–

INV, SANTOS and ALGEBRA.20 These

codes describe the repository, the

movement of radionuclides in

contaminated brine through the

overlying Culebra dolomite, releases of

radionuclides when a drill penetrates

the repository, and calculations of

releases for final results of the PA. EPA

located the majority of the information

in the Users Manuals and Analysis

Packages for each code, found in the

Sandia National Laboratories WIPP

Record Center.

In a few cases, EPA initially found the

theoretical description of the computer

codes to be inadequate. Most notably,

the mathematical description of the

solution precipitation model contained

in the NUTS code, which predicts

radionuclide transport in the repository

and in units underlying the Culebra,

was absent from the documentation.

DOE addressed EPA’s concerns by

providing supplementary reports that

describe in detail those theoretical

discussions that were originally

deficient. With respect to the

documentation pertaining to the method

of analysis, EPA found the descriptions

in the Analysis Packages for each code

to be sufficiently complete. In several

instances, EPA requested that DOE

clarify the written documentation,

which DOE did.

Based on information contained in the

Users Manual and Analysis Packages for

each code and supplementary

information requested by EPA to

address specific problems uncovered in

the course of the compliance review,

EPA found that DOE has provided

sufficient 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. EPA also

found that the level of documentation is

consistent with the ASME requirements

for quality assurance as well as

consistent with recent standards on

ground-water modeling published by

the American Society for Testing and

Materials (ASTM). Therefore, EPA

proposes to determine that DOE has

complied with the requirements of

§ 194.23(c)(1).

b. Descriptions of Models. Section

194.23(c)(2) requires the CCA to

document the following kinds of

information: general descriptions of the

models; discussions of the limits of

applicability of each model; detailed

instructions for executing the computer

codes, including hardware and software

requirements; input and output formats

with explanations of each input and

output variable and parameter; listings

of input and output files from a sample

computer run; and reports on code

verification, bench marking,

validation,21 and quality assurance

(‘‘QA’’) procedures. Section 194.23(c)(3)

requires documentation of the structure

of the computer codes in detail and

complete listings of the source codes.

The codes that EPA reviewed include:

CUTTINGSlS, SECOFL2D, SECOTP2D,

CCDFGF, LHS, PANEL, BRAGFLO,

BRAGFLOlDBR, NUTS, FMT, GRASP–

INV, SANTOS and ALGEBRA. The

supplemental information from DOE

that documented code development was

described above in this section. DOE

also set forth a number of objectives

regarding issues that must be covered in

code documentation to meet the QA

criteria outlined in Sections 4 and 6 of

the ASME NQA–2a–1990 addenda, part

2.7, to ASME NQA–2–1989.

EPA reviewed the supplemental

documents, executed the computer

codes, and evaluated the code

verification, bench marking, and

validation documentation. During its

review, EPA identified a number of

areas where the Agency initially judged

the documentation to be inadequate.

EPA required the Department to perform

an analysis on the NUTS computer

code, to develop a code requirement and

test the statistical validity of certain

aspects of the GRASP–INV code, to

provide evidence that the GRASP–INV

code was tested in a manner consistent

with its implementation in the PA, and

to document a sample computer run

that corresponds to calculation of the

CCA PA results. DOE provided this

additional supporting analysis and

documentation and satisfied EPA’s

concerns.

DOE submitted all of the source code

listings and a detailed description of the

structure of computer codes in the

Implementation Documents for each

code. With this information, a user can

compile the source code and install it

on a computer system identical to that

used in the CCA PA calculation. EPA

found that DOE submitted all of the

source code listings. EPA identified no
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58811

problems with the detailed descriptions

of the structure of the computer codes.

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

that are adequate for use in the CCA PA.

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.

Therefore, EPA proposes to determine

that DOE has demonstrated compliance

with §§ 194.23(c) (2) and (3).

c. Parameters. Section 194.23(c)(4)

requires detailed descriptions of data

collection procedures, data reduction

and analysis, and code input parameter

development. Parameters are numerical

values or ranges of numerical values

used 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. 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.

DOE discussed information

supporting parameter development in

the CCA and in parameter records

located in the SNL WIPP Record Center.

The records at SNL Record Center

include WIPP parameter entry forms,

Parameter Records Packages, Principal

Investigator Records Packages, Data

Records Packages, and Analysis

Packages. DOE uses all of these

documents to explain the full

development of parameter values used

as inputs to the CCA PA calculations.

The Agency reviewed the CCA,

parameter documentation and record

packages for approximately 1,600

parameters used as input values to the

CCA PA calculations. 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:

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 the Agency used

to evaluate the overall quality of SNL’s

documentation traceability. The Agency

examined DOE’s parameter

documentation to see if the following

elements were present: detailed listings

of code input parameters and the

parameters that were sampled; codes in

which the parameters were used and the

computer code names of the sampled

parameters; descriptions of the sources

of data; descriptions of the parameters,

data collection procedures, data

reduction and analysis, and code input

parameter development; discussions of

the linkage between input parameter

information and data used to develop

the input information; discussions of

the importance of the sampled

parameters relative to final calculations

of releases, correlations among sampled

parameters, and how these are

addressed in PA; a listing of the sources

of data used to establish parameters; and

data reduction methodologies used for

CCA PA parameters, including an

explanation of QA activities.

After its initial review, the Agency

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, 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 did not find

adequate documentation to support one

of DOE’s professional judgement

parameters, the waste particle size value

(expressed as a particle diameter). Other

parameters such as professional

judgment parameters and some

parameters that were used in DOE’s

1992 PA calculations were found to

have adequate documentation to

support the value used in the CCA PA

calculations.

During its review, EPA found that the

following types of documentation were

necessary to improve DOE’s records: a

comprehensive database of all

parameters used in the CCA PA, a

database of all parameters based on

experimental data, ‘‘roadmaps’’ that

document and link CCA PA parameters

to their sources, complete record

packages in the SNL Record Center,

background documentation on the

development of those parameters that

were originally used in DOE’s 1992 PA

calculations and again were used in the

CCA PA calculation, and adequate

explanations of why the 149

professional judgment parameters in the

comprehensive parameter database did

not need expert elicitation. DOE

provided all of these pieces of

documentation, primarily by improving

the quality of the records stored in the

SNL WIPP Records Center. The Agency

did not accept the use of professional

judgement to derive the waste particle

size parameter, and thus required DOE

to use the process of expert elicitation

to develop the value for this parameter.

(See also the preamble discussion for

§ 194.26 regarding expert elicitation for

the waste particle size.) After

subsequent review and evaluation of the

SNL WIPP Record Center records and

after completion of expert elicitation,

EPA was satisfied with the additional

documentation provided by DOE for

these areas of concern.

The Agency requested further

documentation from DOE, expressing

concern about information supporting

58 parameters. EPA divided these

parameters into those parameters

lacking supporting evidence, those

parameters that have records supporting

values other than those selected by

DOE, and those parameters that are not

explicitly supported by the relevant data

or information. DOE provided

additional information supporting some

of the parameters of concern to EPA.

The Agency also performed its own

sensitivity analyses for the parameters

to determine if changes to some

parameters have a significant impact on

the final computer calculations. The

Agency’s concerns were resolved for

thirty-four of these parameters, either by

DOE’s submission of additional

documentation or by the results of

sensitivity analyses conducted by EPA

that indicated that changes to certain

parameter values would not
58812 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

significantly impact results of computer

calculations.

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 PA was not significant enough

to necessitate a new PA. EPA directed

DOE to incorporate modified values or

distributions for twenty-four parameters

in the PAVT. 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.

For further information about results of

the PAVT, see the preamble for § 194.34,

‘‘Results of PA.’’ DOE satisfied EPA’s

concerns about the parameters by

incorporating EPA’s changes to the

parameter values and parameter

distributions in the PAVT.

Upon subsequent review and

evaluation, 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. Therefore,

the Agency proposes to determine that

the CCA complies with § 194.23(c)(4).

d. Public Comments on Parameter

Values. During the public comment

period for the ANPR, EPA received

comments on specific parameter values.

After the end of the ANPR public

comment period, EPA also received

comments on parameter distribution

values that the Agency mandated DOE

include in the PAVT.

The Agency performed a thorough

review of the parameters and the

parameter development process, as

discussed in the previous section. In its

initial review, the Agency found that

DOE had a great deal of documentation

supporting most of the parameters used

in the CCA PA available in the SNL

Records Center. EPA specifically

requested DOE to perform the PAVT in

order to determine the effects of

different parameter distributions for

those parameters that concerned EPA

and that appeared to have a significant

impact on the results of PA.

e. Software Licenses. Section

194.23(c)(5) requires the CCA to

document any licenses necessary for

software used in the PA. DOE stated that

it did not use any software requiring

licenses, since software was developed

by DOE or its contractors. EPA concurs

with DOE’s statement, and thus

proposes to find that the CCA complies

with § 194.23(c)(5).

f. Parameter Correlation. Section

194.23(c)(6) requires the CCA to provide

an explanation of the manner in which

models and computer codes incorporate

the effects of parameter correlation.

Parameters are correlated if they are not

completely independent of each other.

For example, if two parameters are

programmed into computer codes so

that both increase or decrease under the

same conditions, the two parameters are

correlated. Such a correlation can be

directly programmed as an explicit

correlation specified by the computer

user. A parameter correlation also can

be programmed into computer codes

indirectly through an induced

correlation when one parameter is used

to derive a second parameter in the

code. EPA evaluated parameter

correlation in the CCA because an

improper parameter correlation may call

into question some parameter values

and may even call into question the

validity of the results from PA,

depending on how significant the

correlated parameters are.

User-specified (explicit) parameter

correlations are introduced into the CCA

PA calculations using a correlation

matrix or table in the Latin Hypercube

Sampling (LHS) computer program. Of

all the parameters, only rock

compressibility and permeability are

explicitly correlated in the LHS

computer code input file. When values

that are sampled using the LHS

computer code are used to calculate

other values in the CCA PA

calculations, an induced correlation

parameter relationship is created

through mathematical formulas used in

subsequent computer codes. This is the

prevalent method of correlation used in

DOE’s PA.

EPA reviewed the documentation in

the LHS Users Manual that explains

how parameter correlation is included

in the parameter sample process. EPA

also reviewed information in the CCA

which discussed the mathematical

methods used to incorporate parameter

correlation into the CCA PA

calculations. EPA also reviewed DOE’s

sensitivity analysis of the parameters

sampled in the CCA PA, which includes

a discussion of the impacts of parameter

correlations.

Based on its review of CCA

documentation and supplementary

information, EPA determined that DOE

has adequately demonstrated the

manner in which the models and

computer codes incorporate the effects

of parameter correlation. Specifically,

the CCA contains adequate: (1)

Discussions that explain how the effects

of parameter correlation are

incorporated; (2) explanations of the

mathematical functions that describe

these relationships; and (3) descriptions

of 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. Thus, the Agency proposes to find

that DOE has demonstrated compliance

with the requirements of § 194.23(c)(6).

5. EPA’s Independent Testing

Section 194.23(d) allows EPA to

verify the results of computer

simulations used in the CCA by

performing independent simulations.

This requirement also requires DOE to

provide EPA with data files, source

codes, executable versions of computer

software for each model, other material

or information needed to permit EPA to

perform independent simulations, and

to access necessary hardware to perform

such simulations within 30 days of a

request from EPA. This requirement

ensures that EPA can verify calculations

in the CCA and analyze the potential

impact of changes to the PA calculations

if changes are made to computer codes

or parameters.

DOE provided EPA with unrestricted

access to computer hardware required to

perform simulations related to the CCA.

DOE also provided EPA with access to

data files, source codes, and executable

computer codes for each model used in

the CCA. DOE provided staff to assist

EPA in executing various verification

tests and sensitivity analyses with DOE

hardware and software. EPA performed

code verification tests on all CCA PA

computer codes using CCA hardware

and software. In some cases, EPA

required DOE to perform additional

verification tests. EPA conducted

extensive parameter sensitivity tests

using the same system of CCA PA

computer codes. The PAVT was an

independent computer simulation of the

WIPP’s performance conducted under

EPA’s authority to require independent

verification computer simulations under

§ 194.23(d). DOE provided assistance in

all of this work on a timely basis.

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,
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58813

EPA proposes to find DOE in

compliance with § 194.23(d). For further

information on EPA’s evaluation of

compliance for § 194.23, see CARD 23.

C. Section 194.24, Waste

Characterization

Section 194.24, waste

characterization, generally requires DOE

to identify and describe quantitative

information on the chemical,

radiological and physical characteristics

of the waste proposed for disposal at the

WIPP that can influence disposal system

performance. The DOE has not

demonstrated compliance with all the

requirements of § 194.24 as they pertain

to waste characterization activities at

generator sites. Therefore, EPA is

proposing certification of compliance

with these requirements, with the

condition that DOE must submit

additional information to demonstrate

full compliance for waste generator

sites. The proposed conditions of

certification are addressed under EPA’s

discussion of the requirements at

§§ 194.24(c)(3) through (5).

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.

DOE described the existing waste by

combining like waste streams into

eleven final waste forms and waste

stream profiles. A waste stream is

defined by DOE as waste material

generated from a single process or

activity that is similar in material,

physical form, isotopic make-up, and

hazardous constituents. The waste

stream profiles contained information

on the waste material parameters, or

components, that could affect repository

performance. DOE extrapolated

information from the existing waste

streams to determine the amount of tobe-generated waste. DOE’s waste

profiles contained appropriate specific

information on the components and

their approximate quantities in the

waste. Therefore, EPA proposes to find

DOE in compliance with § 194.24(a).

Sections 194.24(b)(1) through (3)

require 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. For

example, the waste characteristic gas

generation is controlled, in part, by the

type and amount of waste components

such as metal waste containers and

plastic material. DOE identified wasterelated elements pertinent to the WIPP

as part of its screening for features,

events, and processes (‘‘FEPs’’). The

FEPs used in the performance

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

from which characteristics and

associated components were identified

and further analyzed. (Refer to the

preamble discussion of § 194.32, ‘‘Scope

of PA,’’ for additional information

pertaining to FEPs.)

DOE concluded that six

characteristics were expected to have a

significant effect on disposal system

performance and were used in PA (i.e.,

parameters were identified for each):

solubility, formation of colloidal

suspensions containing radionuclides,

gas generation, shear strength of waste,

radioactivity of specific isotopes, and

TRU activity at disposal. 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 PA. 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 proposes to find DOE in

compliance with requirements in

§§ 194.24(b)(1) through (3).

Section 194.24(c)(1) requires DOE to

specify numeric limits on significant

waste components and demonstrate

that, for those 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. DOE

explicitly included numeric limits,

identified as fixed values with no

associated uncertainty, for four waste

components. Lower limits were

established for ferrous and non-ferrous

metals; upper limits were established

for cellulosics and free water. The three

components related to radioactivity and

radionuclides were effectively limited

by the inventory estimates used in the

PA. The fixed-value limits and

radionuclide inventory estimates were

included in the PA calculations through

parameters closely related to these

components, and the results

demonstrated compliance with EPA’s

standards. 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.

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.

Therefore, EPA proposes to find DOE in

compliance with § 194.24(c)(1).

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).

DOE proposed to use non-destructive

assay (‘‘NDA’’) (e.g., passive active

neutron assay), non-destructive

examination (‘‘NDE’’) (e.g.,

radiography), and visual examination

(‘‘VE’’) as the methods used to quantify

various waste components. The CCA

described numerous NDA instrument

systems and described the equipment

and instrumentation found in NDE and

VE facilities. 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. EPA found that

these methods, when implemented

appropriately, would be adequate to

characterize the important waste

components. Therefore, EPA proposes

to find that DOE has demonstrated

compliance with § 194.24(c)(2).

(Implementation of measurement

programs at waste generator sites is

addressed below for the requirements at

§§ 194.24(c)(4) and (5).)

Section 194.24(c)(3) requires DOE to

demonstrate that the use of process

knowledge to quantify components in

waste for disposal conforms with the

quality assurance (‘‘QA’’) requirements

found in § 194.22. EPA expected DOE to

submit specific information on the

process knowledge to be used at waste

generator sites as part of DOE’s

certification application. EPA requires

such information to conduct proper

regulatory review of whether use of the

process knowledge is appropriate and

reliable. DOE provided some

information on its overall plans for

using process knowledge in the CCA.

DOE did not, however, provide specific

information on the use of process

knowledge at any waste generator site in

the CCA, nor did it provide information
58814 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

22See Docket A–93–02, Item II–I–70 for a list of

these systems and processes. They include

characterization methodologies and relevant

procedures, such as that used for entering data into

the WWIS database.

demonstrating establishment of the

required QA programs.

After submission of the CCA, EPA

subsequently received information

regarding process knowledge to be used

at the Los Alamos National Laboratory

(‘‘LANL’’). EPA determines DOE to have

adequately described the use of process

knowledge for retrievably stored

(legacy) debris waste streams at LANL.

EPA has confirmed establishment and

execution of the required QA programs

at that waste generator site through

inspections. (See the preamble

discussion of § 194.22, ‘‘Quality

Assurance,’’ for further information on

inspections.) Therefore, the Agency

determines that DOE has demonstrated

compliance with the § 194.24(c)(3) QA

requirement for LANL. EPA does not

find, however, that DOE has adequately

described the use of process knowledge

for any other waste streams at LANL

(other than the retrievably-stored

(legacy) debris waste streams discussed

above). Furthermore, DOE has not

demonstrated compliance with

§ 194.24(c)(3) for any other waste

generator site.

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). The

system of controls must conform to the

QA requirements specified in § 194.22

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’’).

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: waste stream

screening/verification (pre-shipment)

and 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’’). If

implemented as proposed, EPA believes

that the TRU QAPP, WAC, and WWIS

are adequate to control important

components of waste emplaced in the

WIPP. EPA audited DOE’s QA programs

at CAO, SNL and WID and determined

that DOE properly adhered to QA

programs that implement the applicable

NQA standards and requirements. (See

the preamble discussion of § 194.22 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 to be

used at LANL. The Agency confirmed

through inspections that the system of

controls is adequate to characterize

waste and ensure compliance with the

limits on waste components, and also

confirmed that a QA program had been

established and executed at LANL in

conformance with NQA 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. Therefore, EPA determines DOE

to have demonstrated compliance with

§§ 194.24(c)(4) and (5) for several waste

streams in the category of retrievably

stored (legacy) debris waste at LANL.

EPA’s proposed determination of

compliance is limited to those

retrievably stored (legacy) debris waste

streams that can be characterized using

the systems and processes audited by

DOE, inspected by EPA, and found to be

adequately implemented at LANL. 22

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.

In order to ship transuranic waste

from other waste generator sites for

emplacement at the WIPP, DOE will

have to demonstrate compliance with

the § 194.24(c)(3) through (5)

requirements. Compliance with the

requirements as they relate to QA

programs will be evaluated and

approved for each generator site in

accordance with the language in

Condition 2 (‘‘Quality Assurance’’) of

the proposed Appendix A to 40 CFR

Part 194. To fully comply with these

requirements, DOE must also submit—

and EPA must approve—for each waste

stream or group of waste streams,

information on how process knowledge

will be incorporated into waste

characterization activities, and on the

system of controls proposed for (a) given

waste stream(s). A waste stream is

defined by DOE as waste material

generated from a single process or

activity that is similar in material,

physical form, isotopic make-up, and

hazardous constituents. EPA expects

that this information will be contained

in site-specific documents including, for

example, site certification quality

assurance plans (‘‘QAPs’’) and quality

assurance project plans (‘‘QAPjPs’’). All

such documentation submitted by DOE

regarding plans for waste

characterization of specific waste

streams will be placed in EPA’s dockets

for public inspection.

As waste generator sites establish

waste characterization programs for new

waste streams (or groups of waste

streams), EPA will assess their

compliance with the §§ 194.24(c)(3) and

(4) requirements. EPA will conduct an

audit or inspection of a DOE audit at

each site to evaluate the use of process

knowledge and the establishment of a

system of controls for each waste stream

or group of waste streams. In order for

a site to demonstrate the

implementation of a system of controls,

the WWIS must be demonstrated to be

functional at any waste generator site

before any waste stream(s) may be

shipped from that site for disposal at the

WIPP. By this, EPA means that a waste

generator site must demonstrate that it

has procedures in place for entering

data into the WWIS tracking system,

and that such data can be transmitted to

the WWIS database so that it is available

for compilation and reporting. In order

for EPA to confirm that a system of

controls has been adequately executed

in accordance with § 194.24(c)(4), DOE

must demonstrate that measurement

techniques and control methods can be

implemented for each waste stream or

streams which DOE plans to emplace in

the WIPP.

As described in the proposed

certification condition, EPA’s decision

to approve site-specific plans for the use

of process knowledge and the system of

controls—and thus to approve a site to

transport a waste stream for disposal at

the WIPP—would be made only after

public comment has been solicited and

after EPA has conducted an audit or an

inspection of a DOE audit of the waste

generator site. Therefore, before making

any determination to approve the use of

process knowledge or the system of

controls, EPA would publish a notice in

the Federal Register announcing its

intent to evaluate waste characterization

programs for a given waste stream (or

waste streams) at one or more sites.

There would be allowed at least a 30-

day comment period on DOE’s proposed

programs for process knowledge and a
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58815

system of controls for one or more

specific waste streams.

EPA believes that approval of site

specific QA programs is required by,

and that this proposed procedure is

consistent with the provisions of

Section 194.24(c)(3)–(5) because it

requires DOE to (1) demonstrate

application of established and executed

quality assurance programs to use of

process knowledge; (2) demonstrate

implementation of the required system

of controls; and (3) demonstrate

application of established and executed

quality assurance programs to the

system of controls, at the individual

waste generator sites prior to shipment

of wastes from such sites. EPA requests

comment on whether the Agency should

place a condition on its certification of

compliance at WIPP consisting of future

demonstrations by DOE that the

§§ 194.24(c)(3)–(5) requirements have

been met, prior to shipment of TRU

waste to WIPP from such sites. In

particular, EPA requests comment on its

preliminary conclusion that the

proposed procedures for determining

whether adequate quality assurance

programs have been established and

executed by DOE are consistent with 40

CFR Part 194. However, if, based upon

public comment on today’s proposed

action, EPA concludes that it would be

appropriate to make clarifying changes

to 40 CFR Part 194 that specifically set

forth these procedures, EPA may do so

as part of its final action on today’s

proposal.

EPA’s written determination that DOE

has demonstrated compliance with

these requirements, as well as the

results of any audits or inspections,

would be placed in the public dockets.

EPA will confirm ongoing compliance

with these requirements through

unfettered access to waste generator

sites for the purpose of conducting

inspections under its authority at

§§ 194.21 and 194.24(h).

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. DOE elected to assume

that radioactive waste would be

emplaced in the WIPP in a random

fashion. 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. 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

DOE had assumed random waste

loading and also had found that

potential non-random loading of waste

would not affect releases, a final waste

loading plan was unnecessary. EPA

determined that DOE cross-referenced

the resultant waste distribution

assumptions from the waste loading

plan with the waste distribution

assumptions used in PA, and 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. EPA proposes to find 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 LWA. Specifically, the LWA defines

limits for: surface dose rate for remotehandled (‘‘RH’’) TRU waste, total

amount (in curies) of RH–TRU waste,

and total capacity (by volume) of TRU

waste to be disposed. (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 two-phase

waste characterization (pre-shipment at

generator sites, and pre-receipt at the

WIPP). The CCA stated that the WWIS

will be used to track specific data

related to each of the 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. 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 proposes to

find 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 proposes to find

that DOE is in compliance with

§ 194.24, and that LANL has

demonstrated compliance with

§§ 194.24(c)(3) through (5) for certain

retrievably stored (legacy) debris waste

streams 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). EPA’s

proposed determination of compliance

is limited to those retrievably stored

(legacy) debris waste streams that can be

characterized using the systems and

processes audited by DOE, inspected by

EPA, and found to be adequately

implemented at LANL.

The Agency also proposes to certify

compliance subject to the condition that

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 at a generator

site, and (2) DOE has demonstrated that

the system of controls described in

§ 194.24(c)(4) 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 can be

implemented for each waste stream

which DOE plans to dispose in the

WIPP. As discussed in the preamble for

§ 194.22 (and in Condition 2 of the

proposed Appendix A to 40 CFR Part

194), 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 Agency proposes that the

decision to allow a waste generator site

to dispose of a waste stream at the WIPP

will be made only after public

comments have been solicited on DOE’s

proposed site-specific programs and

after EPA has conducted an audit or an

inspection of a DOE audit of the waste

generator site. EPA will make available,

in its public docket, the site-specific

program documents being considered by

the Agency, and will publish a notice in

the Federal Register announcing its

intent to evaluate such plans. There will

be allowed at least a 30-day public

comment period for interested parties to

comment on DOE’s proposed programs

for process knowledge and a system of

controls for one or more specific waste

streams. EPA also plans to conduct an
58816 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

audit or an inspection of a DOE audit at

each site to evaluate the execution of

such plans for pertinent waste streams.

EPA’s approval of the plans relevant

to compliance with §§ 194.24(c)(3) and

(4) will be indicated in a letter from the

Administrator’s authorized

representative to the Department. EPA is

proposing to define the Administrator’s

authorized representative as ‘‘the

director in charge of radiation programs

at the Agency’’ to clarify the delegation

of responsibilities described in the

Compliance Criteria and in the

proposed conditions of certification. A

copy of the approval letter, as well as

the results of any inspections, will be

placed in the public dockets. After

approval of the site-specific plans for

characterization of (a) waste stream(s),

EPA will confirm the execution of the

programs at each waste generator site

and continued compliance with the

requirements of §§ 194.24(c)(3) through

(5) through inspections and audits

under its authority at §§ 194.21,

194.22(e) and 194.24(h). Results of such

inspections will be made available to

the public through the Agency’s public

dockets, as described in § 194.67.

For specific language on the waste

characterization conditions of

certification, see Condition 3 of the

proposed Appendix A to 40 CFR Part

194; for specific language on the quality

assurance requirements that relate to

waste characterization, see Condition 2

of the proposed appendix. For further

information on EPA’s evaluation of

compliance for § 194.24, refer to CARD

24.

D. Section 194.25, Future State

Assumptions

Section 194.25 stipulates that

performance assessments (‘‘PA’’) and

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

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.

EPA required DOE to identify and

document all future state characteristics

and conditions that are used in the PA

and CA. For all elements of the PA and

CA that do not relate to hydrogeologic,

geologic or climatic conditions, DOE

was required to assume that

characteristics of the future remain what

they are at the time the compliance

application was prepared. DOE was

required to document the effects of

potential changes to hydrogeologic,

geologic and climatic conditions on the

disposal system. For geologic

conditions, EPA required DOE to

address dissolution, near surface

geomorphic features and processes, and

subsidence in the geologic units of the

disposal system. For climatic

conditions, EPA required DOE use

current climatic conditions for

comparison and to consider cycles of

increased precipitation.

In accordance with § 194.25(a), DOE

provided a description of the future

state assumptions for the features,

events and processes (‘‘FEPs’’) used in

the PA and CA. Except where specified

otherwise (i.e., §§ 194.32 and 194.33),

DOE assumed that current

characteristics for the FEPS not related

to hydrogeology, geology and climatic

conditions will remain constant

throughout the 10,000-year regulatory

time frame. EPA reviewed the

information in the CCA and agrees with

the future state assumptions that DOE

has made. EPA found this information

to be inclusive of all relevant elements

of the PA and CA.

To fulfill the requirements of

§ 194.25(b)(1), DOE predicted the

potential future hydrogeologic

conditions at the WIPP. DOE developed

several future state assumptions about

the hydrogeological conditions of the

WIPP, such as increased precipitation

impacts on recharge location and

capacity, hydraulic gradient, and

transmissivity in the Culebra member of

the Rustler and Dewey Lake formations.

In a few cases, DOE found that

hydrogeologic conditions can change

with time and can possibly affect the

PA. DOE addressed these potential

changes in the PA. EPA reviewed the

adequacy of the uncertainty of key

parameter assumptions, such as the

impacts of mining subsidence on

Culebra transmissivity. EPA found that

DOE adequately addressed the effects of

mining-induced subsidence on Culebra

hydrogeologic conditions. EPA

reviewed the future state assumptions

DOE made about hydrogeologic

conditions and concludes that DOE has

accurately characterized and modeled

the potential changes from current

conditions. EPA found that DOE’s

incorporation of these changes into the

PA was adequate. Other potential

changes to hydrogeologic conditions,

notably those associated with climate

change, are addressed in the discussion

of § 194.25(b)(3).

Section 194.25(b)(2) requires DOE to

consider the effects of potential changes

to geologic conditions on the disposal

system. DOE predicted potential future

geologic conditions at the WIPP. DOE

analyzed the stratigraphy and

physiography of undistributed geologic

conditions, salt creep and excavationinduced stress changes, geochemistry,

seismic activity, disturbed rock zone,

dissolution, and mining in the McNutt

potash zone above the repository. DOE

also analyzed the geologic effects of

existing boreholes, brine reservoirs, and

drilling intrusions. EPA found DOE’s

assumptions of the future geologic

conditions to cover the significant

geologic units and conditions that affect

PA and determined that the screening

arguments adequately justify the

exclusion of the majority of the

geological FEPs from the PA and CA.

For additional information on the FEPs

included in the PA and CA, see

§ 194.32. EPA evaluated the CCA and

additional information provided by DOE

at EPA’s request regarding the

uncertainty associated with deep

dissolution and considers DOE’s

analysis adequate. For additional

information on both geologic and

hydrogeologic conditions of the WIPP,

see § 194.14(a).

Section 194.25(b)(3) requires DOE to

consider the effects of potential changes

to climatic conditions on the disposal

system. At the WIPP, availability of

water for recharge is the primary

concern related to global climate

change. Future global warming would

be expected to continue the trend to less

precipitation in the vicinity of the WIPP

(which would be beneficial to disposal

system performance). DOE concluded

that global cooling—and increased

precipitation—is the worst case scenario

for the WIPP. In accordance with

§ 194.25(b)(3), DOE identified and

described the effects of increased

precipitation in future cooler climate

cycles on the repository. DOE

considered potential increased

participation over the next 10,000 years

and incorporated the uncertainty of the

effects of this climate change in the PA

through modeling of dissolution,

groundwater flow, and potential

radionuclide transport in groundwater.

DOE described climate change due to
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58817

potential natural causes and the

resulting changes in recharge rates,

groundwater flow velocity, and flow

direction. DOE included models of the

impact of potential climate changes on

groundwater flow in the Culebra over

the regulatory time period.

EPA found that the CCA included

adequate discussions of the current and

previous climate at the WIPP site and

found that DOE addressed the impacts

of potential climate change over the

regulatory time frame. EPA concludes

that DOE appropriately considered

climate-related factors such as

precipitation, temperature, and

evapotranspiration that might affect

groundwater flow in the regional threedimensional groundwater basin model.

EPA also examined DOE’s descriptions

of recharge associated with potential

climate change effects and found that

DOE adequately described the

uncertainties associated with potential

change to the future climate cycles. For

additional information on climate

change ground water flow, see

§§ 194.14(a) and (i).

In addition, EPA evaluated potential

hydrogeologic changes related to

climate change, including: groundwater

recharge, Culebra flow rate variations,

and water table elevation. EPA

evaluated the additional information

DOE provided at EPA’s request

regarding vertical inflow to the Dewey

Lake Formation and three-dimensional

groundwater flow modeling, and

concluded that DOE provided adequate

documentation to sufficiently address

the issues. EPA verified that the CCA

acknowledges and quantifies

uncertainties in hydrogeologic

conditions found in the site

characterization data descriptions and

modeling assumptions. EPA also found

that DOE modeled the effects of climate

changes during the next 10,000 years on

the groundwater flow in the Culebra.

After reviewing the CCA and the

additional information provided by DOE

at EPA’s request, EPA concluded that

DOE’s explanation of uncertainty

associated with the potential wetter

climate impacts on Culebra

transmissivities resulting from potential

dissolution of fracture infillings is

acceptable.

EPA determined that the overall CCA

approach to dealing with uncertainty,

and the examples of conservative

assumptions used to compensate for

uncertainty, is consistent with the FEPs

list, screening arguments, and model

descriptions. EPA proposes to find DOE

in compliance with § 194.25. For further

information on EPA’s evaluation of

compliance with § 194.35, refer to

CARD 25.

E. Section 194.26, Expert Judgment

The requirements of § 194.26 apply to

expert judgment elicitation. 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 (‘‘QA’’)

requirements in accordance with

§ 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 § 194.26(a)

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 and timely

collection of data.

The CCA submitted on October 29,

1996, did not identify any expert

elicitation activities. During the

Agency’s review of PA parameters, EPA

found that inadequate explanation and

information was provided on the

derivation of 149 parameters identified

in the CCA as resulting from

professional judgment (e.g., code control

parameters, physical constants). The

Compliance Criteria do not provide for

utilization of ‘‘professional judgment.’’

Input parameters are to be derived from

data collection, experimentation, or

expert elicitation. EPA requested in

letters to DOE dated March 19, April 17,

and April 25, 1997, 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) In

the absence of data collection or

experimentation, EPA expected DOE to

derive these input parameters through

expert elicitation.

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 to enhance the

traceability of parameter values. EPA

deemed the documentation provided by

DOE adequate to demonstrate proper

derivation of all but one of the so-called

professional judgment parameters—the

waste particle size distribution

parameter. The remaining parameters

questioned by EPA were found to have

adequate documentation to support the

values used in the CCA PA calculations.

For further discussion of the technical

review of PA parameters, see the

preamble for § 194.23. EPA required

DOE to use the process of expert

elicitation to develop the value

distribution for the waste particle size

parameter. (Docket A–93–02, Item II–I–

27)

The waste particle size parameter is

important in the PA because it 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.

DOE conducted the expert judgment

elicitation on May 5 through May 9,

1997. The process included: definition

of technical issues; public notification;

selection of experts; general orientation

and elicitation training; presentation

and review of issues; preparation of

expert analysis by elicitor; discussion of

analysis by panel members; elicitation;

recomposition; review and approval of

dissenting opinions provided by

experts; and documentation of the

process and results. 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. This

particle size distribution was

incorporated in the PAVT calculations;

for a detailed discussion on the

sampling of uncertain parameter

distributions, refer to the preamble

discussion of § 194.34, ‘‘Results of PA.’’

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)

EPA proposes to find that DOE complies

with § 194.26(a) because the Agency

found adequate support for the

derivation of all parameter values with

the exception of the waste particle size

parameter, for which DOE undertook an

expert elicitation.

EPA’s review of DOE’s compliance

with the requirements of § 194.26

principally focused on the conduct of

the elicitation process. Sections 194.26

(b) and (c) set specific criteria for the

performance of an expert judgment

elicitation. DOE must: identify the

expert judgments used to support the

compliance application; identify the

experts involved in the process;

describe the process of eliciting expert
58818 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

judgment; document the results;

document that the experts have the

necessary independence and

qualifications for addressing the

questions and issues presented; explain

the connection between the questions

posed to the expert panel and the

manner in which the final report of the

panel is used in the compliance

application; adhere to requirements on

the composition of the expert panel,

including the fraction of the panel

members who are employed by DOE;

assure the public be given the

opportunity to present their views in the

expert judgment process; and document

the elicitation process so as to

demonstrate a logical progression from

the first statement of issue given to the

panel to the combination and

presentation in the final report.

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, curriculum vitae

of panel members, background

documents, and presentation materials.

EPA also assessed compliance with the

QA requirements of § 194.22. EPA found

that the documentation provided by

DOE addressed the requirements of

§ 194.26(b)(2).

In accordance with § 194.26(b)(1),

DOE identified the individual experts

on the panel. EPA found that the expert

panel was composed of six experts,

including four from consulting firms

and two associated with universities.

Two of the six panel members were

DOE contractors at the time of the

elicitation.

Therefore, in accordance with

§ 194.26(b)(7), the panel included at

least five individuals, two-thirds of

whom were not employed by DOE or

DOE contractors. In accordance with

§ 194.26(b)(3), the panel did not include

individuals who will use the judgments

or who maintain, at any organizational

level, a supervisory role or who are

supervised by those who will utilize the

judgment. EPA found DOE’s

documentation to demonstrate

compliance with these requirements.

Based on its review of curriculum

vitaes and completed organizational

conflict of interest forms, EPA

determined that the experts on the panel

demonstrated the required

independence and level of knowledge

required by the questions or issues

presented. (§ 194.26(b)(4)) EPA found

the background and orientation

materials addressed the relationship

among information and issues as well as

the purpose and intent of the judgment,

in accordance with § 194.26(b)(5). The

Agency determined that the expert

elicitation met the requirement at

§ 194.26(b)(6) since the result of the

process was a parameter distribution

that could be implemented directly in

the PA. EPA also found that DOE

afforded the public an opportunity to

present scientific and technical views to

the expert panel. (§ 194.26(c))

Based on the review of expert

elicitation supporting documentation

developed by DOE and its contractors,

as well as the results of the EPA audit

to verify compliance, EPA proposes to

determine that DOE complies with the

requirements of § 194.26 in conducting

the required expert elicitation.

Numerous public comments were

received on DOE’s statement that it did

not conduct any expert judgement

activities in developing the CCA. As

many commenters correctly pointed out,

the CCA did not contain adequate

information to allow a reviewer to

ascertain whether a large number of the

input parameters were properly derived

in accordance with the explicit

requirements of the Compliance

Criteria. DOE subsequently provided

additional information, and

substantially improved the quality of

the records at the SNL Records Center

to make it possible to confirm that all

but one of the suspect input parameters

were adequately supported. For further

discussion of EPA’s evaluation of

compliance with § 194.26 and related

public comments, see CARD 26.

F. Section 194.27, Peer Review

Section 194.27(a) requires DOE to

conduct peer review evaluations related

to conceptual models, waste

characterization analyses, and the

evaluation of engineered barriers. This

section, at §§ 194.27(b) and (c)(1), also

requires DOE to submit documentation

showing that the required peer reviews

were conducted in a manner compatible

with NUREG–1297, ‘‘Peer Review for

High-Level Nuclear Waste

Repositories.’’ (Docket A–92–56, Item

III–B–1h) NUREG–1297 is incorporated

by reference in the Compliance Criteria.

As stated in NUREG–1297, the purpose

of peer review is to provide confidence

in the validity of technical and

programmatic judgments involving

scientific uncertainty or ambiguity by

subjecting those judgments to the

evaluation of qualified, independent

specialists. (NUREG–1297, p. 2)

DOE completed the required peer

reviews and included a description of

the peer review process in the CCA.

EPA’s CAG indicates the types of

documentation necessary for § 194.27(b)

to demonstrate that peer reviews were

conducted in accordance with the

NUREG–1297 guidance. For example,

the CCA should show the process by

which peer review panels deliberated,

should present the conclusions they

reached, and should show that panel

members were qualified and free of

conflicts of interest. EPA reviewed the

CCA to determine whether DOE’s

procedures and plans for the required

peer reviews were consistent with the

CAG and whether the required peer

reviews had actually been conducted in

accordance with those procedures and

plans.

Many of the documents detailing

DOE’s implementation of NUREG–1297

are kept by DOE as quality assurance

(‘‘QA’’) records and were not included

in the CCA but were made available to

EPA. EPA first reviewed the CCA and

supplementary reports and confirmed

that the required peer reviews had been

conducted. To evaluate the peer review

process further, EPA conducted an audit

of DOE’s QA records for peer review in

February 1997. The audit consisted of

an extensive review of DOE’s records

and interviews with DOE staff and

contractors who managed the required

peer reviews. The audit raised several

isolated findings, but none of these was

sufficient to lead EPA to conclude that

any of the peer reviews had been

conducted in a manner incompatible

with NUREG–1297.

EPA proposes to find DOE in

compliance with §§ 194.27(a) and (b).

DOE submitted documentation in the

CCA showing that the required peer

reviews had been conducted. DOE’s

procedures for the conduct of peer

review satisfactorily incorporated the

essential elements of NUREG–1297, as

identified in the CAG. The audit

conducted by EPA verified that DOE

properly followed its procedures for

peer review.

Section 194.27(c)(1) requires DOE to

show that the three required peer

reviews, if conducted prior to

promulgation of 40 CFR Part 194, were

conducted in accordance with an

alternative process substantially

equivalent to NUREG–1297. Because

DOE conducted the required peer

reviews after the promulgation of 40

CFR Part 194, this requirement is not

applicable.

Section 194.27(c)(2) requires DOE to

document any peer reviews conducted

by DOE other than those required by

§ 194.27(a). The additional peer reviews

were not required to be compatible with

the guidance in NUREG–1297, but EPA

recommended in the CAG that they be

documented in a manner similar to the

required peer reviews. EPA expected
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58819

23 ‘‘Disposal’’ is defined as ‘‘[P]ermanent isolation

of . . . radioactive waste from the accessible

environment with no intent of recovery whether or

not such isolation permits the recovery of such fuel

or waste. For example, disposal of waste in a mined

geologic repository occurs when all of the shafts to

the repository are backfilled and sealed.’’ 40 CFR

191.02(l)

that documentation would be sufficient

to identify the purpose, scope,

membership, and findings of a given

peer review.

DOE developed a list of criteria, based

principally on guidance in NUREG–

1297, to determine whether a review

activity conducted prior to

promulgation of the Compliance Criteria

constituted a peer review. DOE then

identified past activities that met the

criteria and incorporated relevant

documentation in the CCA. EPA

reviewed the materials provided and

found that sixteen peer reviews were

properly included in the CCA. EPA also

found that the CCA contained sufficient

documentation to allow EPA to identify

the purpose, scope, membership, and

findings of those sixteen peer review

activities. Therefore, EPA proposes to

find DOE in compliance with

§ 194.27(c)(2).

Comments received in regard to peer

review expressed mainly two concerns.

First, commenters considered the CCA

incomplete because some peer reviews

were reopened after the CCA was sent

to EPA in October 1996. EPA requested,

received, and docketed pertinent

documentation resulting from the

reopened peer reviews prior to

determining that the CCA was complete.

Second, commenters questioned the

findings of some peer reviews. EPA’s

compliance review for § 194.27(b)

focused on the extent to which the

required peer reviews were conducted

in a manner compatible with NUREG–

1297. The Agency believes that the

critical evaluation of peer review

findings is necessary but not directly

relevant to DOE’s compliance with

§ 194.27. EPA carefully examined the

findings of all peer reviews conducted

after the promulgation of 40 CFR Part

194 and discusses them under the

relevant technical sections: quality

assurance (§ 194.22), conceptual models

(§ 194.23), waste characterization

(§ 194.24), passive institutional controls

(§ 194.43), and engineered barriers

(§ 194.44). For further information of

EPA’s evaluation of compliance for

§ 194.27, see CARD 27.

XI. Containment Requirements

The disposal regulations include

requirements for containment of

radionuclides. The containment

requirements at 40 CFR 191.13 specify

that release of radionuclides to the

accessible environment shall not exceed

specific limits, which are based on the

amount of waste in the WIPP at the time

of disposal. (§ 194.31) Assessment of the

likelihood that the WIPP will meet these

release limits is conducted through use

of a process known as performance

assessment (‘‘PA’’). The WIPP PA

essentially consists of a series of

computer simulations that attempt to

describe the physical attributes of the

disposal system (site, geology, 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 then translated into computer code.

The results of the simulations show the

potential releases of radioactive

materials from the disposal system to

the accessible environment over the

10,000-year regulatory time frame.

(Models and computer codes are

addressed in more detail in the

preamble for § 194.23 of the general

requirements.)

The PA must include both natural and

man-made processes and events which

have an effect on the disposal system. It

must consider all reasonable potential

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 both

human-initiated releases (e.g., via

drilling intrusions) and releases by

natural processes that would occur

independently of human activities. The

requirements at §§ 194.32 and 194.33

address the scope of PA and the types

of human intrusion which must be

considered in PA.

The results of 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’’ (discussed in more depth in

subsequent sections of this preamble).

The results of PA are assembled into

complementary cumulative distribution

functions (‘‘CCDFs’’) which indicate the

probability of exceeding various levels

of normalized releases. Section 194.34

of the WIPP Compliance Criteria

imposes specific statistical requirements

on the results of PA and on the single

curve used to judge compliance with the

containment requirements.

A. Section 194.31, Application of

Release Limits

Section 194.31 indicates that DOE is

to quantify releases of radionuclides

from the WIPP in terms of ‘‘cumulative

releases,’’ which are calculated from

‘‘release limits.’’ Release limits for

radionuclides at a radioactive waste

disposal facility must be calculated in

accordance with 40 CFR Part 191,

Appendix A. There, a ‘‘release limit’’ for

a radionuclide is introduced as a

measure of the cumulative amount of

radioactivity, measured in curies, that is

allowed to reach the accessible

environment (that is, land surface, the

atmosphere, surface waters, oceans, and

all the land beyond the boundary of the

WIPP land withdrawal area) over the

10,000 years after the disposal 23 of

radioactive waste. Release limits are to

be calculated using the activity from

radioactive waste, in curies, that will

exist in the WIPP at the time of disposal.

To calculate normalized releases and

release limits, DOE must first identify

all the radionuclides that are present in

the waste that it plans to put in the

WIPP (e.g., plutonium-238). Next, the

Department projects which

radionuclides will be present in the

waste at the time of disposal, including

those isotopes created by radioactive

decay between the time of the waste

inventory (approximately 1995) and the

time of disposal (estimated to be the

year 2033). DOE then determines which

of these radionuclides emit alphaparticles, have an atomic number greater

than that of uranium (transuranic), and

have half-lives greater than twenty

years. These radionuclides comprise the

‘‘TRU component’’ of the waste. The

total activity of the TRU component of

the waste, in curies, divided by one

million curies, is called the ‘‘waste unit

factor.’’ For the WIPP, Table 1 of

Appendix A of 40 CFR Part 191 presents

values of release limits (in curies) per

unit of this ‘‘waste unit factor.’’

To obtain the release limit for a

radionuclide, DOE must multiply each

release limit value in Table 1 by the

numerical value of the waste unit factor.

Finally, to obtain the normalized release

for a scenario, DOE must divide the

projected estimated release (obtained

from PA modeling), in curies, for every

radionuclide (whether TRU or nonTRU) by its respective release limit, and

sum these quotients.

In the CCA, the Department provided

an inventory of the various

radionuclides in the waste expected at

the time of disposal, including those

radionuclides in the waste inventory

that are currently stored at different

DOE sites, those radionuclides that are

projected to be generated at different

DOE sites between 1995 and the time of
58820 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

disposal, and those radionuclides that

would be created by radioactive decay

between the time of the waste inventory

in 1995 and the time of disposal,

approximately in the year 2033. The

waste inventory showed that plutonium

and americium produce almost all of the

radioactivity from waste that would be

in the WIPP at the time of disposal.

Based on the fifteen radionuclides in the

inventory that were transuranic, alphaemitting, and had half-lives greater than

twenty years, DOE calculated that the

relevant total activity at the time of

disposal would be 3.44 million curies

and that the waste unit factor would be

3.44.

DOE used the waste unit factor to

obtain the release limit for each

radionuclide found in Table 1 in

Appendix A of 40 CFR Part 191. These

release limits were then used in the

calculation of cumulative releases. The

Department designated six transuranic

radionuclides that contributed more

than 99.9 percent of the activity as

‘‘major radionuclides.’’ The Department

calculated the release limits and relative

contributions to releases for the six

major radionuclides using a computer

program called EPAUNI. The

Department verified the computer

calculations with sample hand

calculations.

EPA reviewed DOE’s description of

the procedure used to estimate the

activity of waste proposed for disposal,

examined DOE’s hand calculations, and

verified the computer code and output

to determine whether DOE correctly

calculated the waste unit factor,

including radioactive decay up to the

year 2033. EPA also evaluated whether

DOE appropriately calculated release

limits for each major radionuclide and

identified the relative contribution of

each major radionuclide.

EPA found DOE’s simplification of

using the six transuranic radionuclides

that contribute the greatest activity in

computer calculations to be appropriate.

Because these six radionuclides would

make up more than 99.9 percent of the

activity from the transuranic waste,

DOE’s simplification could contribute at

most an error of 0.1 percent to its

calculations of the contribution to

releases from individual radionuclides,

which would not have a significant

impact upon the calculation of release

limits or the contribution to releases

from individual radionuclides.

EPA found that the TRU waste

component used to calculate the waste

unit factor of 3.44 omitted some waste

stored at an off-site facility at Savannah

River. DOE corrected this error by

recalculating the waste unit factor based

on a TRU inventory that included the

Savannah River waste; the revised waste

unit factor was 3.59. EPA did not

require DOE to recalculate the release

limits based on the new value for the

waste unit factor, because using the

larger revised factor would have

resulted in higher release limits (and

thus, lower normalized releases). That

is, the use of the incorrect value in the

CCA is more conservative than using the

correct value of 3.59. The correction of

the error would only show that the

WIPP will comply with the disposal

regulations by a wider margin than had

been previously demonstrated.

The Agency confirmed that the

Department calculated the waste unit

factor of 3.44 and the release limits at

the time of disposal in accordance with

the requirements of Appendix A of 40

CFR Part 191. In addition, the Agency

found that the Department correctly

identified the relative contribution of

each major radionuclide to releases.

Finally, the Agency confirmed that the

computer codes, model results, and

hand calculations were consistent and

thus supported the use of the computer

codes. Because the Agency’s review

concluded that the Department

calculated release limits for the WIPP

using an appropriate methodology and

conservative waste inventory estimates,

the Agency proposes that the

requirements of § 194.31 have been met.

For further information on EPA’s

evaluation of compliance for § 194.31,

see CARD 31.

B. Section 194.32, Scope of Performance

Assessments (PA)

Section 194.32 requires DOE to

consider, in the performance assessment

(‘‘PA’’), both natural and man-made

processes and events which can have an

effect on the disposal system. EPA

expected DOE to consider all features,

events and processes (‘‘FEPs’’) that may

have an effect on the disposal system. In

particular, EPA expected DOE to

consider mining effects on hydraulic

conductivity, fluid injection, future

development of leases and existing

boreholes in the scope of the PA. The

CCA was also expected to document

which FEPs (or sequences or

combinations of FEPs) are included in

the PA. DOE is required to document

the decision not to include any feature,

event, or process in the PA. Deep and

shallow drilling, over the regulatory

time frame, are addressed in more detail

in the preamble discussion of § 194.33.

To fulfill the requirements of

§§ 194.32(a), (d) and (e), DOE developed

and followed a process for considering

FEPs in the PA. DOE initially identified

1,200 FEPs from a list of FEPs

developed by the Swedish Nuclear

Power Inspectorate (‘‘SKI’’). This list

was compiled and categorized based on

location of occurrence and cause by

nine organizations world wide. DOE

modified this list to make it relevant to

WIPP. DOE’s final list of FEPs was then

classified and screened for

consideration in the PA. DOE screened

FEPs from consideration in the PA

based on regulatory exemption, low

probability and low consequence. FEPs

were then combined to form scenarios.

Scenarios were also screened based on

regulations, probability or consequence.

The remaining scenarios were retained

for implementation in the PA. The CCA

documents DOE’s decision not to

include specific FEPs in the PA.

Approximately 237 FEPs were

retained for screening. DOE concluded

that 17 of 72 initial natural FEPs should

be retained for the PA, including

stratigraphy, shallow dissolution,

saturated groundwater, infiltration,

precipitation, and climate change. Of

108 waste and repository-induced FEPs,

DOE concluded that 51 of these should

be retained for the PA, including

disposal geometry, waste inventory, salt

creep, backfill chemical composition,

actinide solubility, spallings, and

cavings. DOE concluded that 15 of the

57 human-initiated events and

processes should be retained for the PA,

including oil and gas exploration.

Examples of FEPs screened from use in

the PA include: lateral dissolution,

regional tectonics, salt deformation,

mechanical effects of backfill, liquid

waste disposal and groundwater

extraction.

EPA concluded that the initial FEP

list assembled by DOE was sufficiently

comprehensive, in accordance with

§§ 194.32(a) and (e)(1). In compiling this

list, DOE appropriately screened out

events and processes on the basis of

probability, consequence or regulatory

requirements. DOE considered and

incorporated into the PA numerous

natural processes and events, mining,

and deep drilling. DOE considered

shallow drilling and appropriately

screened it out on the basis of low

consequence. (See preamble for

§ 194.33.)

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,

in accordance with § 194.32(d).

Review of the CCA and the submitted

supporting documents confirms that

DOE used a thorough process to identify

all the appropriate FEPs as well as the

related combinations and sequences that

can potentially occur within the
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58821

regulatory time frame and affect

disposal system performance. EPA

determined that the process is

sufficiently documented and that DOE

justified the retention and elimination

of FEPs. 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). DOE

provided documentation and

justification for eliminating those FEPs

that were not included in the PA. In

some cases (e.g., fluid injection and

dissolution), the CCA did not provide

adequate justification or convincing

arguments to eliminate FEPs from

consideration in PA. (Fluid injection is

discussed in more detail below, relative

to compliance with § 194.32(c).)

However, DOE provided supplemental

information and analyses to

demonstrate compliance with

§ 194.32(e)(3). EPA found this

supplementary information to be

adequate in fulfilling the requirements

to justify FEP exclusion from the PA.

For disturbed scenarios (i.e., human

activities), DOE discussed how mining

was incorporated into the PA. DOE

identified potash as the only natural

resource currently being mined near the

WIPP. DOE, in accordance with

§ 194.32(b), used the EPA-specified

mining probability and considered

changes in hydraulic conductivity up to

1000 times the base hydraulic

conductivity of the Culebra. In its

calculation of the potash area to be

mined, DOE considered minable

reserves inside and outside of the

controlled area. The Compliance

Criteria require DOE to examine only

currently extractable resources, not to

speculate on what other resources may

become economically viable.

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.

These values for hydraulic conductivity

considered the impact of institutional

controls on mining, mining practices

and mineral resources. 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. EPA

proposes to find that DOE complies

with § 194.32(b).

EPA’s review of the CCA raised

questions regarding DOE’s analysis, in

accordance with § 194.32(c), of humaninitiated activities, including fluid

injection. 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. An oil well operator,

Mr. Hartman, drilling in the Salado

Formation in the Rhodes-Yates Field,

encountered a salt water blowout in an

oil development well. In subsequent

litigation, the court found that the

source of the water flow was injection

water from a long-term waterflood

borehole located more than a mile away.

DOE addressed the fluid injection

scenario in the CCA with an analysis of

waterflooding (for enhanced oil

recovery) and brine disposal activities.

(Docket A–93–02, Item II–G–1,

Reference #611) In accordance with

§ 194.32(c), DOE determined that these

two activities were the only fluid

injection scenarios that were currently

occurring or could be initiated in the

near future in the vicinity of the WIPP.

DOE identified the Bell Canyon

Formation under the Salado and Castile

Formations as the primary target for

fluid injection for brine disposal. DOE

stated that this scenario had the

potential to produce more brine inflow

to the WIPP. DOE modeled the fluid

injection scenario using WIPP geology,

and again using the geology identified

in the Rhodes-Yates Field. The two sites

differ significantly because the Castile

Formation, which underlies the Salado

at the WIPP, is absent in the RhodesYates Field. DOE assumed that fluid

injection activities would occur

continuously for 50 years, and evaluated

the subsequent effects of such injection

activities over the entire 10,000-year

regulatory time frame. The modeling

results indicated that some brine could

potentially get into the WIPP from fluid

injection activities. However, the

amount of brine from the worst case

scenario (the ‘‘Rhodes-Yates’’ scenario)

was low compared to the amount of

brine expected to enter the waste area

naturally. DOE thus screened out the

fluid injection scenario on the basis of

low consequence.

EPA’s review of the CCA raised

additional questions regarding DOE’s

screening analysis of fluid injection.

EPA believes that 50 years is an accurate

estimate for the life of a single oil field,

but that it does not account for the

possibility of multiple fields. Because

drilling restrictions currently applicable

to potash areas in the Delaware Basin

could be lifted, it is possible that

multiple oil fields could be developed

in the foreseeable future near the WIPP.

Based on the current resources and

leases in the vicinity of the WIPP, EPA

estimated that oil could still be drilled

up to 150 years from now. EPA thus

required DOE to extend the 50-year time

frame in its models to 150 years. EPA

also required DOE to use modified

values for some input parameters, and

to model the behavior of the disturbed

rock zone consistent with assumptions

used in the PA. (Docket A–93–02, Item

II–I–17) Finally, EPA required DOE to

provide additional information on the

frequency of fluid injection well

failures.

In supplemental work on fluid

injection, DOE addressed all the issues

identified by EPA. DOE modified the

computer model grid configuration and

added a new model to address concerns

raised by both EPA and stakeholders.

DOE researched injection well operating

practices and construction in the

Delaware and identified significant

differences between those in the vicinity

of the WIPP and the Rhodes-Yates Field.

For example, wells near the WIPP are

typically less than ten years old and are

constructed to much higher mechanical

standards than the older, less robust

wells found in the Rhodes-Yates Field.

DOE identified a range of well failure

scenarios, from undetectable brine flow

to catastrophic well failure. DOE’s data

indicated that the probability of a

catastrophic well failure in the vicinity

of the WIPP is extremely low. DOE

confirmed that the presence of the

Castile at the WIPP also substantially

inhibits injected brine movement into

the Salado anhydrite markerbeds.

Public comments on this issue

included a detailed report that

contradicted the DOE fluid injection

modeling and indicated that fluid

injection activities could overwhelm the

WIPP with brine. (Docket A–93–02, Item

II–H–28) EPA has reviewed the report

and considers it to model conditions

that are highly unrealistic for the WIPP.

For example, all modeled scenarios

assumed that the entire volume of brine

was injected directly into the anhydrite

marker beds in the Salado Formation. In

addition, the report modeled the

occurrence of fluid injection well

beyond the time frame contemplated by

§ 194.32(c). The report also ignored

current well construction and fluid

injection operating practices, which are

more robust than that used in the 45-

year-old Rhodes-Yates Field.

EPA agreed with commenters that the

original fluid injection screening was

not adequate. Thus EPA required DOE

to provide additional information and to

do additional modeling. The additional

modeling showed rates of brine inflow

(and thus effects on the disposal system)

even smaller than those estimated by

the original CCA screening analysis.

DOE provided documented evidence

that the well construction and operating

practices near the WIPP are much more

robust than that in the Rhodes-Yates
58822 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

well. Both DOE’s research and EPA’s

own review of fluid injection, indicated

that the probability of a long-term fluid

injection well failure is below the

regulatory cutoff of 1 in 10,000 over

10,000 years. Based on DOE’s modeling

and examination of fluid injection

practices, EPA believes that a salt water

blowout situation in the Rhodes-Yates

Field is extremely unlikely to occur and

affect WIPP’s ability to contain

radionuclides. Thus, EPA concurs with

DOE that fluid injection is a lowprobability scenario that can be

screened out of the PA based on low

consequence.

DOE, in accordance with § 194.32(c),

also 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. DOE included

and assessed the potential effects of

existing boreholes as part of its FEPs

screening analysis. DOE concluded that

natural borehole fluid flow through

abandoned boreholes would be of little

consequence during current and

operational phase activities. In addition,

DOE screened out the occurrence of

flow through undetected boreholes

based on low probability.

To further address § 194.32(c), DOE

assessed scenarios ranging from the

effects of deep and shallow drilling and

mining to undisturbed disposal system

performance. DOE retained the FEPs

describing both undisturbed and

disturbed system performance. DOE

identified the specific locations in the

CCA that related to modeling of the

individual FEPs. These discussions

focused on conceptual model

development, but often linked the

conceptualizations with associated

computational (computer) models.

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. However, DOE inadequately

analyzed in the application some future

activities in the vicinity of the disposal

system, including injection of drilling

fluids for brine disposal and enhanced

oil recovery, solution mining, and full

extraction potential of the leaseholds (in

the vicinity of WIPP). In response to the

concerns expressed by EPA and

stakeholders, DOE conducted additional

analyses and submitted follow-up

information. This information was

adequate and EPA concurred with the

conclusions, concluding that DOE’s

analysis met the requirements of

§ 194.32(c).

In summary, EPA proposes to find

DOE in compliance with § 194.32. For

further information on EPA’s evaluation

of compliance for § 194.32, refer to

CARD 32.

C. Section 194.33, Consideration of

Drilling Events in PA

Section 194.33 requires DOE to make

specific assumptions about future deep

and shallow drilling in the Delaware

Basin. Section 194.33 requires that the

following assumptions be incorporated

into the PA: drilling will occur

randomly in space and time; the drilling

rate may vary with the resources;

drilling practices will remain constant

for a single resource but may be

different for others; and plugging

practices will remain constant, but the

permeability of a borehole may change

with time. Deep and shallow drilling

practices and related activities can

directly impact the cumulative potential

for contaminant release to ground,

surface or geologic units.

For this requirement, EPA required

DOE to discuss the resources for which

deep and shallow drilling occur in the

Delaware Basin. DOE was also required

to describe the techniques and rates for

deep and shallow drilling for each

resource. In these analyses, DOE was

required to document assumptions and

sources of information. EPA also

required DOE to document assumptions

that DOE made in analyzing the

consequences of drilling events in PA.

Finally, DOE was required to evaluate

the effects of boreholes on the properties

of the disposal system.

To fulfill the requirements of

§ 194.33(a), DOE identified several deep

and shallow drilling activities as being

present in the Delaware Basin. DOE

identified oil and gas exploration and

exploitation, and water and potash

exploration, as the principal drilling

activities to be considered in the PA.

The shallow drilling components of

these activities were screened from

inclusion in the PA because DOE

considered these activities to be of low

consequence to PA calculations. DOE

considered three scenarios in PA for

deep drilling: (1) One or more boreholes

penetrate(s) the Castile brine reservoir

and also intersect(s) a repository panel,

(2) one or more boreholes intersect(s) a

repository panel, and (3) multiple

penetrations of waste panels, by

boreholes of the first or second type, at

many possible combinations of

intrusion times, locations and

combinations of borehole types. EPA

found that the PA incorporated deep

and shallow drilling events, in

accordance with § 194.33(a).

To comply with the requirements of

§ 194.33(b), DOE incorporated

assumptions into the PA about the

severity, frequency and randomness of

human intrusion. DOE considered

intermittent and inadvertent drilling,

including exploratory and

developmental drilling, as the most

severe human intrusion scenarios and

used them to calculate cumulative

radionuclide releases. The drilling rate

is one of the most important parameters

affecting compliance with the

containment requirements. Using a

publicly available petroleum database,

DOE established the rate of future deep

drilling to be 46.8 boreholes per square

kilometer per 10,000 years. EPA found

that DOE identified the number of deep

drilling events for each resource, and

that sources of information used to do

so were thorough and appropriate. (The

rate of shallow drilling in the Delaware

Basin was not needed because, as noted

above, shallow drilling was screened

from inclusion in the PA based on low

consequence.) DOE applied the deep

drilling rate in the PA by randomly

sampling with respect to: (1) The

location of a borehole in the repository

footprint, and (2) the time of occurrence

during the regulatory time frame. EPA

therefore proposes to find DOE in

compliance with § 194.33(b).

DOE evaluated, in accordance with

§ 194.33(c), 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. DOE evaluated borehole

drilling and borehole seal degradation

for their effects on properties of the

disposal system and their impact on

radionuclide migration and transport.

DOE determined that boreholes can

impact radionuclide migration and

transport through cuttings, cavings,

spallings and direct brine releases. In

addition, DOE considered the effects of

borehole degradation and its impact on

the permeability of borehole plugs.

EPA and public commenters

disagreed with the constant value DOE

used in the PA for the short-term (up to

200 years after disposal) borehole plug

permeability. EPA therefore directed

DOE to use a range of borehole plug

permeabilities when conducting the

EPA-mandated Performance Assessment

Verification Test (‘‘PAVT’’). While

EPA’s sensitivity analysis indicated that

the short-term plug permeability

affected some performance measures,

the results of the PAVT demonstrated

that the range of short-term plug

permeability values, compared to the

long-term borehole permeability, had

little impact on the results of modeling.
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58823

EPA and public commenters also

disagreed with DOE’s use of a small

range of values for the long-term

borehole plug permeability. (Docket A–

93–02, Item II–I–17) For example, one

commenter asserted that DOE should

evaluate both ‘‘perfect plugs’’ (i.e., low

permeability) and plugs that ‘‘fail’’ (i.e,

very high permeability). (Docket A–93–

02, Item II–E–34, comment #113) In the

PAVT, the long-term borehole plug

permeability was changed so that the

sampled parameter range included both

low and high permeability values to

simulate perfect plugs and borehole

plug failure, respectively. Low

permeability plugs did increase releases

by increasing repository pressure and

allowing more spallings and direct brine

releases. However, the PAVT results

indicated that changing the long-term

borehole permeability, in combination

with several other changes requested in

public comments (notably those related

to pressurized brine pockets), still

would not cause predicted releases to

violate the containment requirements;

this indicates that the original CCA

parameter values were acceptable for

comparison to the containment

requirements. (See preamble discussion

of § 194.34 for further information on

the PAVT.)

EPA reviewed the information

contained in the CCA and concluded

that DOE demonstrated that the effects

of drilling events have been adequately

considered. EPA found that the

documentation in the CCA

demonstrated that DOE thoroughly

considered deep and shallow drilling

activities and rates within the Delaware

Basin. EPA found that DOE

appropriately screened out shallow

drilling from consideration in the PA.

EPA also found that DOE appropriately

incorporated the assumptions and

calculations for drilling into the PA as

stipulated in §§ 194.33(b) and (c). EPA

determined that the PA models did not

incorporate the effects of techniques

used for resource recovery, in

accordance with § 194.33(d). EPA

further concludes that the information

in the CCA is consistent with available

data. EPA proposes to find DOE in

compliance with the requirements of

§ 194.33. For further information on

EPA’s evaluation of compliance for

§ 194.33, see CARD 33.

D. Section 194.34, Results of PA

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 194.34 of

the Compliance Criteria provides

specific requirements for presenting the

results of the PA for the WIPP.

The restriction on releases of

radioactive material is expressed in

terms of ‘‘normalized releases’’ or

‘‘cumulative releases.’’ Normalized

releases refer to amounts of radioactivity

projected (by means of the mathematical

models of the PA) to be released from

the repository over 10,000 years under

various physical conditions and

intrusion scenarios. To calculate the

normalized release for a given intrusion

scenario, one first obtains the

normalized release separately for each

individual radionuclide; this involves

dividing the amount projected to be

released, in curies, by its radionuclidespecific release limit, as calculated in

accordance with Appendix A of 40 CFR

Part 191. (See the discussion of release

limits for § 194.31 in today’s preamble.)

One then adds together the normalized

releases for all radionuclides to

determine the overall normalized

release for the scenario. Section 191.13

requires that a disposal system be

designed so that there is reasonable

assurance 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.

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 PA. The

PA must include a statistically sufficient

number of CCDFs; in particular, the

number of CCDFs must be large enough

to ensure that the maximum CCDF

curve exceeds the 99th percentile of the

population of CCDFs, with at least a 95

percent probability, at the specific

values of 1 and 10 for normalized

releases. 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.

EPA found that the CCA PA

demonstrated that the WIPP meets the

containment requirements of § 191.13

by more than an order of magnitude in

probability. The largest release at any

point on the mean CCDF curve was a

normalized release of only 0.3. The PA

calculations indicated no cases where

cumulative releases would be ten times

greater than the release limits.

In the process of reviewing the CCA,

the Agency and public commenters

raised concerns about certain

assumptions and specific parameter

values incorporated into the PA. Also,

DOE found some coding problems in the

PA computer software. The Agency

therefore directed the Department to

conduct additional modeling that

included corrections to computer

coding problems and modifications to

parameter values and distributions. The

PAVT also excluded the assumption of

credit for passive institutional controls.

EPA required this additional modeling

in the PAVT in order to determine

whether the cumulative impact of the

changes in the PA codes and parameters

would be small enough that the WIPP

would still meet the containment

requirements of § 191.13. (For further

discussion of parameter values, see the

discussion of parameters in the

preamble for § 194.23.) The results of

the PAVT showed somewhat higher

cumulative release values than the

original CCA PA. However, even these

higher cumulative release values were

more than an order of magnitude lower

than the containment requirements, at

the probability levels prescribed by

§ 191.13. Based upon the results of the

CCA PA and the PAVT, EPA proposes

to find that the WIPP meets the

containment requirements of § 191.13.

Further discussion of the specific

compliance criteria of § 194.34 follows.

1. Complementary Cumulative

Distribution Functions (CCDFs)

Section 194.34(a) requires DOE to

report the results of the PA in the form

of ‘‘complementary, cumulative

distribution functions’’ (‘‘CCDFs’’),

which may be presented graphically as

a set of curves. A CCDF curve presents

the probability that releases from the

repository, caused by all significant

processes and events, might exceed any

particular level of cumulative

(normalized) release. That is, a point on

a CCDF curve displays, on the vertical

axis, the relative number of release

scenarios or ‘‘futures’’ that could result

in calculated releases larger than the

corresponding normalized release value

found on the horizontal axis. Each

CCDF curve starts with a maximum

probability of one on the left side of the

graph (i.e., there is a 100% probability

that cumulative releases from the

disposal system will be either zero or

greater, and will not take on negative

values); and then decreases toward the

right as the normalized release becomes
58824 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

larger, and as relatively fewer

simulations yield releases that exceed

the corresponding normalized release

value.

Each CCDF curve in the CCA is

calculated using 10,000 simulations or

‘‘futures,’’ each of which models a tenthousand year period in which a series

of human intrusion events may occur.

(For further information about how the

possible effects of human intrusion are

included in the PA, see the preamble

discussions of §§ 194.32 and 194.33.) A

single CCDF curve uses a fixed set of

uncertain physical, chemical and

geologic characteristics at the WIPP and

its surroundings, but uses 10,000

different, randomly-determined

sequences of intrusion events. Different

CCDF curves are developed by using

different information about the

uncertain physical, chemical and

geologic characteristics of the WIPP and

its surroundings. The CCA PA included

300 different CCDF curves so that, in all,

it calculated normalized releases for

three million different possible futures.

EPA reviewed features, events and

processes, scenarios, conceptual models

and computer codes that support CCDF

generation. EPA found that all

significant features, events and

processes and scenarios were included

in the generation of CCDFs. (See

preamble discussions of §§ 194.32 and

194.33 for more detailed information on

EPA’s evaluation of PA scenarios.) DOE

used the same approach in calculating

and presenting results of the

Performance Assessment Verification

Test (‘‘PAVT’’).

The Agency found that DOE

assembled the results of the CCA PA

and the PAVT into CCDFs incorporating

all significant processes and events.

Therefore, the Agency proposes to find

DOE in compliance with the

requirements of § 194.34(a).

2. Generation of the Full Range of

CCDFs

Section 194.34(e) requires the CCA to

display the full range of CCDFs

generated. The CCA included all three

hundred CCDFs. These were presented

in three graphs, one for each replicate of

one hundred CCDF curves. In addition,

DOE provided summary CCDF curves

for descriptive statistics. DOE generated

a mean CCDF curve, 95th-percentile

confidence bound curves for the mean,

a 10th percentile curve, a median curve,

and a 90th percentile curve for each

replicate, and generated a mean curve

and 95th-percentile confidence bound

curves for the mean of all three

replicates. The Department also

provided the same information for the

PAVT.

EPA determined that the CCA

displayed the full range of CCDF curves

over the full range of CCDF values and

displays normalized releases relevant to

the determination of DOE’s compliance

with § 194.34(e). EPA also concluded

that DOE applied the same methodology

to the PAVT for displaying the full

range CCDF curves over the full range

of probabilities and normalized releases.

Therefore, EPA proposes to find that

DOE has demonstrated compliance with

§ 194.34(e).

3. Probability Distributions and Random

Sampling of Uncertain Parameters

Section 194.34(b) requires DOE to

develop and document probability

distributions for uncertain disposal

system parameter values used in PA.

Section 194.34(c) requires DOE to use

and to document computational

techniques which draw random samples

from across the entire range of these

probability distributions to generate

CCDFs.

Parameters are numerical values or

ranges of numerical values used 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 parameters are

well-established chemical and physical

constants, such as Avogadro’s Number

or the Universal Gas Constant. Other

parameters describe characteristics

unique to the WIPP, such as the

solubility and mobility of specific

actinides in brines in the WIPP. It is not

possible to determine a single, constant

value to describe particular

characteristics of the WIPP, in which

case one must consider a range of

values. The relative probabilities of

occurrence of different uncertain

parameter values within that range can

be presented as a mathematical

expression known as a probability

distribution. A probability distribution

may be described in terms of statistical

parameters such as the average (mean),

median, maximum and minimum

values of the parameter, or standard

deviation. Section 194.34(b) requires

development and documentation of

these probability distributions.

DOE selected 57 uncertain parameters

whose values were to be obtained

through random sampling in the PA.

DOE also performed a sensitivity

analysis to show if changes to some

parameter values would affect the

results of PA.

The uncertainty in the value of a

parameter is built into PA computer

codes by programs that ‘‘sample,’’ or

select, numeric values from within the

probability distribution for that

parameter. Section 194.34(c) requires

these sampling techniques to draw

random samples from across the entire

range of each probability distribution.

This requirement ensures that PA

calculations fully consider the possible

extremes of calculated releases of

radioactivity without systematically

underestimating or overestimating

releases.

The Department used the Latin

Hypercube Sampling (‘‘LHS’’) code to

sample the parameter distributions

related to physical, chemical and

geologic conditions of the repository

and its surroundings. DOE used Monte

Carlo-type random sampling to

determine the effects of human

intrusion through drilling or mining.

Both codes select values from across the

entire range of the probability

distributions. The LHS code requires

fewer samples to cover the entire range

of the distribution because it samples

randomly within divisions spread

across the entire probability

distribution.

EPA reviewed the parameters used in

the modeling, the probability

distributions for the sampled parameters

and DOE’s sensitivity analysis. As a

result of its review, the Agency found

that 58 parameter values and

distributions were not well supported

by the data available. (See the preamble

discussion of § 194.23 for further details

on EPA’s review of parameters.) EPA

performed its own sensitivity analysis

on some parameters to determine if

uncertainties in the parameter values of

concern would have a significant impact

on the PA. The Agency concluded that

many of the parameters of concern had

little impact, but twenty-four parameters

could significantly affect the PA results,

either individually or in combination

with other parameters.

As a result of the parameter review,

EPA requested that DOE perform

additional modeling. This additional

modeling, the PAVT, included, among

other things, parameter value and

distribution modifications to twentyfour parameters that the Agency

believed might have a significant impact

on the results of PA. DOE conducted the

PAVT using the same computer codes

and the same sampling methodologies

as for the CCA PA, but changed the 24

parameters in accordance with EPA’s

direction and modified some of the

computer codes in response to EPA’s

questions about the codes. DOE

conducted 300 simulations for the

PAVT, resulting in 300 CCDF curves,

just as for the CCA PA. The results of

the PAVT showed higher normalized

releases than those in the CCA PA, but

were still more than an order of
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58825

magnitude below the containment

requirements at § 191.13. Thus, the

PAVT incorporated changes that

addressed EPA’s concerns about PA,

and showed that the resulting releases

were still within the containment

requirements. Because the PAVT used

identical technical methods to the CCA

PA, EPA concludes that the PAVT

results are numerically equivalent to

those that would be obtained by

performing a new PA incorporating the

changes required in the PAVT. EPA

believes that the PAVT verifies that the

original CCA PA was adequate for

comparison against the radioactive

waste containment requirements.

Because DOE has developed and

documented the probability

distributions for uncertain disposal

system parameter values used in the PA,

EPA proposes to find the DOE to be in

compliance with § 194.34(b). After

reviewing the results of sensitivity

analyses and of the PAVT, the Agency

concludes that the probability

distributions are adequate. The Agency

found that the LHS and Monte Carlo

sampling techniques draw random

samples from across the entire ranges of

the probability distributions used for the

uncertain disposal system parameters in

the PA. The use of these computational

techniques are documented in the CCA.

Therefore, EPA proposes to find that

DOE has demonstrated compliance with

§ 194.34(c).

4. Sufficient Number of CCDFs

Generated

Section 194.34(d) requires DOE to

generate a sufficiently large number of

CCDF curves to ensure that, at

cumulative releases of 1 and 10, the

maximum CCDF exceeds the 99th

percentile of the population of CCDFs

with at least a 95-percent probability.

Section 194.34(d) also requires DOE to

calculate cumulative release values

according to Note 6 of Table 1 in

Appendix A of 40 CFR Part 191.

The PA process uses techniques based

upon probability theory to calculate the

potential for releases. Because of the

many sources of uncertainty, a

computer model could calculate results

of billions of situations without

exhausting every possibility. However,

running billions of simulations is not

feasible given the cost and time

involved. Furthermore, this is not

necessary in order to provide a

reasonable expectation that a disposal

system will contain waste and protect

human health and the environment. So

long as the PA includes a large enough

number of randomly-produced

simulations covering the full range of

possible calculated release values, the

results of PA will yield a valid result

that shows whether or not a disposal

system meets the containment

requirements of § 191.13. (61 FR 5230)

Section 194.34(d) provides a statistical

test to determine if the CCA contains

enough CCDF curves: there must be at

least a 95 percent probability that the

CCDF curve generated in PA with the

highest cumulative release exceeds the

99th percentile of the entire population

of CCDFs (that is, the full range of

possible calculated release values).

As was mentioned above in this

section, each CCDF is generated using a

specific set of sampled values from

distributions of uncertain parameters

related to the physical, chemical and

geologic conditions of the repository

and its surroundings. In the case of the

WIPP, the CCA PA included three sets

or replicates of one hundred CCDF

curves, for a total of 300 CCDF curves.

Each of the CCDF curves is based upon

a sample of 57 uncertain parameters.

DOE used the LHS code to take

samples of the parameter values. The

Department also presented a

probabilistic analysis, based on the

definition of the 99th percentile, and

determined that there would be a 0.95

probability that at least one CCDF curve

will exceed the 99th percentile so long

as the PA includes at least 298 CCDF

curves. Since the CCA PA included 300

CCDF curves, DOE concluded that this

was enough CCDF curves to meet the

requirements of § 194.34(d).

EPA agreed with DOE’s argument

based upon probability and the

definition of the 99th percentile, and

concluded that the CCA PA generated a

sufficient number of CCDFs. As another

approach to evaluating compliance with

§ 194.34(d), EPA also examined the

statistical characteristics of the 300

CCDF curves in the CCA PA. EPA

compared the CCDF curves in the CCA

PA to a statistical distribution that the

Agency believes is a plausible

description of what the entire

population of all possible CCDFs would

produce. EPA found that the maximum

CCDF curve in the CCA PA had a higher

cumulative release than the 99th

percentile predicted using the

probability distribution which

represents the entire population of

CCDFs. Based upon this statistical

analysis, the Agency concluded that

there was at least a 95 percent

probability that the maximum CCDF

curve would exceed the 99th percentile

of the population of CCDFs.

Section 194.34(d) also requires PA to

calculate cumulative release values

according to Note 6 of Table 1 in

Appendix A of 40 CFR Part 191. DOE’s

approach to calculating cumulative

release (or ‘‘normalized release’’) values

is described in the introduction to this

section of the preamble. EPA found

DOE’s approach to be consistent with

Note 6 of Table 1 in Appendix A of 40

CFR Part 191.

EPA found that DOE generated 300

CCDF curves in the PA, using the

appropriate method to calculate

cumulative releases, as specified in Note

6 of Table 1 in Appendix A of 40 CFR

Part 191. Because of the statistical

arguments described above, EPA is

satisfied that the number of CCDFs is

large enough such that, at cumulative

releases of 1 and 10, the maximum

CCDF generated exceeds the 99th

percentile of the population of CCDFs

with at least a 0.95 probability.

Therefore, EPA proposes to find that

DOE has demonstrated compliance with

§ 194.34(d).

5. Compliance of the Mean CCDF

Section 194.34(f) requires the CCA to

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. This statistical

demonstration allows DOE to

demonstrate compliance using a finite

number of CCDFs, rather than having to

generate the entire (infinitely large)

population of CCDFs.

In order to meet the requirements of

§ 194.34(f), DOE must calculate the

mean CCDF curve from all 300 CCDF

curves generated in the CCA PA, must

compute the 95 percent confidence

limits for that overall mean curve, and

must compare the 95 percent upper

confidence limit CCDF curve to the

containment requirements of § 191.13.

The DOE must show that the mean of its

300 CCDF curves, and the 95th

percentile upper confidence limit on the

mean, both lie below a probability of 0.1

at a cumulative release value of 1, and

lie below a probability of 0.001 at a

cumulative release value of 10.

In the CCA, DOE presented the steps

used in its PA to generate the 300 CCDF

curves. DOE also showed how it then

calculated the mean of all CCDFs, by

first computing the mean CCDF for each

of the three replicates of 100 curves, and

then averaging those three mean CCDF

curves. Using the three mean CCDF

curves, DOE calculated the 95 percent

confidence limits for the overall mean

CCDF curve. DOE identified the mean of

all CCDFs generated and the 95 percent

confidence limits and showed that both

the mean CCDF and the CCDF for the

upper confidence limit satisfy the

containment requirements by more than

an order of magnitude.
58826 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

EPA examined DOE’s calculations of

the mean CCDF curve and the CCDF

curve for the 95 percent confidence

limit on the mean, and found that they

were appropriate and were correctly

executed. EPA concurred with DOE’s

conclusion that both the mean CCDF

and the CCDF for the upper confidence

limit satisfy the containment

requirements by more than an order of

magnitude.

As discussed above, EPA was

dissatisfied with many of the parameter

ranges and values used in PA and had

concerns about some codes and the

assumption of credit for passive

institutional controls. EPA required

DOE to perform the PAVT to determine

whether the cumulative impact of the

changes in PA codes and parameters

would require additional PA runs. DOE

applied the same methodology in the

CCA PA and in the PAVT for calculating

the mean CCDF curve and the 95

percent upper confidence limit. The

PAVT results demonstrate that the level

of statistical confidence is significantly

greater than 95% that the mean of the

CCDFs meets the § 191.13 containment

requirements. Therefore, EPA concludes

that the final results of the PAVT are

also in compliance with the

containment requirements of § 191.13

and that the results are presented in

accordance with § 194.34(f).

A public comment received on EPA’s

Advance Notice of Proposed

Rulemaking (ANPR) expressed concern

about the fact that at least some of the

CCDF curves in the CCA PA indicated

that there would be releases into the

accessible environment. EPA’s

containment requirements limit the

likelihood of releases at specific levels,

but do not require DOE to demonstrate

that no releases of any magnitude will

occur. EPA recognized that some

parameters used in CCA PA were

questionable, and required DOE to

perform a PAVT that included revised

parameters in order to alleviate

concerns such as those raised by the

commenter. Less than one percent of

CCDF curves in the CCA PA exceeded

normalized releases of one. EPA

concludes that the probabilities of such

releases are still well below the EPA

release limits.

The CCA demonstrates that there is at

least a 95 percent level of statistical

confidence that the mean of the

population of CCDFs meets the

containment requirements of § 191.13.

(The PAVT results indicate that PA

would still demonstrate that the WIPP is

in compliance with the containment

requirements of § 191.13, even

including substantial modifications to

some of the significant uncertain

parameters used in PA.) Therefore, EPA

proposes that the WIPP complies with

the containment requirements of

§ 191.13 and with § 194.34(f). EPA

believes that the WIPP will safely

contain radioactive waste for up to

10,000 years after disposal and will

protect public health and the

environment. For further information on

the EPA’s evaluation of compliance for

§ 194.34, or on the results of the PA or

the PAVT, see CARD 34.

XII. Assurance Requirements

In 40 CFR 191.14, EPA included six

qualitative assurance requirements to

assure that the desired level of

protection is achieved at disposal

facilities. (60 FR 5777) The assurance

requirements address active

institutional controls, monitoring,

passive institutional controls,

engineered barriers, consideration of the

presence of resources, and removal of

waste. These measures are designed to

compensate for the inherent uncertainty

in projecting the behavior of natural and

engineered components of the

repository for many thousands of years.

(50 FR 38072) The assurance

requirements are implemented at the

WIPP by §§ 194.41 through 194.46 of the

WIPP Compliance Criteria.

A. Section 194.41, Active Institutional

Controls

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 may

not be considered in the PA for more

than 100 years after disposal.

In evaluating DOE’s compliance with

§ 194.41, EPA sought a detailed

description of DOE’s proposed AICs and

how those controls would be

implemented. EPA reviewed this

description for thoroughness, feasibility,

and likely effectiveness. 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. 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.

DOE stated that it would maintain the

proposed AICs for at least 100 years

after closure of the WIPP, and that the

WIPP PA assumed that AICs would

prevent human intrusion for that period.

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,

groundwater pumping, surface

excavation, potash exploration,

hydrocarbon exploration, construction,

and hostile or illegal activities). EPA

also examined the assumptions made by

DOE to justify the assertion that AICs

will be completely effective for 100

years. The assumptions were that: (1)

The fence and signs will convey the

message that the WIPP site is hazardous

and protected; (2) legal prohibitions on

resource recovery activities will be

enforced; and (3) the time required to

initiate a resource extraction operation

will allow routine site patrols to

discover and halt such activities.

EPA found the assumptions regarding

longevity and efficacy of the proposed

AICs to be acceptable. This finding was

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.

Section 194.41 prohibits the

consideration of contributions from

AICs in the PA for more than 100 years

after disposal. Contributions from AICs

in the PA are considered as a reduction

in the rate of human intrusion. 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.

EPA found the description of each

active control measure (fence, signs,

roadways, site maintenance, and

security patrols) and its location to be

adequate to support its intended

function. Also, 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 proposes to

find DOE in compliance with § 194.41.

For further information on EPA’s
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58827

evaluation of compliance for § 194.41,

refer to CARD 41.

B. Section 194.42, Monitoring

Section 194.42 implements the

assurance requirement that DOE

monitor the disposal system to detect

deviations from expected performance.

The monitoring requirement

distinguishes between pre- and postclosure monitoring because of the

differences in the monitoring techniques

that may be used during operations (preclosure) and once the repository has

been backfilled and sealed (postclosure). Monitoring is intended to

provide information about the

repository that may affect the results of

the PA or containment of waste.

To meet the criteria of § 194.42, EPA

required DOE to conduct an analysis of

the effects of disposal system

parameters on the containment of waste.

At a minimum, this analysis must

include the seven specific parameters

listed in § 194.42(a). DOE was required

to present the analysis methodology,

assumptions and results. DOE also was

required to justify the decision not to

monitor any of the parameters analyzed.

(§ 194.42(b))

Section 194.42 requires that the

screening of parameters be conducted to

develop plans for pre- and post-closure

monitoring described in §§ 194.42(c)

and (d). In accordance with § 194.42(e),

these monitoring plans must: (1)

identify the parameters to be monitored

and how the baseline data will be

determined, (2) indicate how the

parameters will be used to evaluate

deviations from the expected

performance of the disposal system, and

(3) discuss the length of time over

which each parameter will be

monitored.

DOE conducted an analysis of

disposal system parameters that

included the parameters specified in

§ 194.42(a), along with other parameters.

The analysis assigned high, medium or

low significance to each parameter for

its importance to the containment of

waste and to the verification of

predictions about disposal system

performance. DOE then screened

parameters out of consideration for

monitoring based on the ability of the

parameter to produce meaningful data

during the monitoring period and on

whether parameters can be monitored

without violating disposal system

integrity.

EPA evaluated the analysis and

screening of parameters, including the

methodology, assumptions, and results.

EPA found that the analysis included

the required parameters and adequately

justified both the selection and rejection

of parameters for inclusion in

monitoring plans. Therefore, EPA

proposes to find DOE in compliance

with §§ 194.42(a) and (b).

Based on the results of its analysis,

DOE submitted plans that identified ten

parameters that will be monitored for

pre-closure monitoring, five of which

will also be monitored for post-closure

monitoring. The pre-closure monitoring

parameters are: (1) Culebra groundwater

composition, (2) change in Culebra

groundwater flow, (3) probability of

encountering a Castile brine reservoir,

(4) drilling rate, (5) subsidence

measurements, (6) waste activity, (7)

creep closure and stresses, (8) extent of

deformation, (9) initiation of brittle

deformation and (10) displacement of

deformation features. Parameters one

through five are also post-closure

monitoring parameters. The parameters

selected for monitoring included several

of those listed in § 194.42(a), such as

creep closure and stresses, extent of

deformation, initiation of brittle

deformation, displacement of

deformation features, Culebra ground

water composition and flow and Castile

brine reservoir location.

The CCA described how DOE intends

to implement monitoring programs for

both pre-and post-closure parameters.

The monitoring plans included

information on establishing baseline

data, how monitoring data will be used

to evaluate deviations from expected

performance and on the length of time

each parameter will be monitored. EPA

finds that DOE submitted monitoring

plans in accordance with §§ 194.42(c),

(d), and (e). The monitoring plans in the

CCA addressed both pre-closure

monitoring (planned to begin before

emplacement of waste) and post-closure

monitoring (using methods that would

not jeopardize containment of waste in

the disposal system), and included

information required by the Compliance

Criteria.

EPA proposes to find DOE in

compliance with the requirements of

§ 194.42. In accordance with its

authority under § 194.21, EPA intends

to conduct an inspection of the preclosure monitoring activities prior to

emplacement of waste to confirm

implementation of the plans detailed in

the CCA. The results of this inspection

will be placed in the public dockets

described under § 194.67. For further

information on EPA’s evaluation of

compliance for § 194.42, see CARD 42.

C. Section 194.43, Passive Institutional

Controls

The Compliance Criteria at § 194.43

require a description of passive

institutional controls (PICs) that will be

implemented at the WIPP. PICs are

measures that do not require human

intervention in order to warn away

potential intruders from disposal sites.

EPA defined PICs in the disposal

regulations as markers, public records

and archives, government ownership of

a site and restrictions on land use at the

site, and any other means of preserving

knowledge of a site. (50 FR 38085) PICs

are intended to deter unintentional

intrusions by people who otherwise

might not be aware of the presence of

radioactive waste at the site.

Sections 194.43(a)(1) through (3) of

the Compliance Criteria implement the

disposal regulations by requiring DOE

to: (1) identify the controlled area by

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). Such 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.

The PICs design proposed by DOE in

the CCA calls for the construction at the

WIPP site of a large earthen berm,

dozens of granite monuments, and three

granite information rooms, two of which

will be buried for their protection. DOE

also proposed to bury thousands of

small markers at shallow depths around

the site. All markers except the berm

will be engraved with warning messages

in several languages and of varying

complexity.

DOE plans to distribute WIPP records

and other information to over one

hundred archives, record centers,

professional organizations, and

commercial enterprises in the United

States and abroad. Finally, DOE points

to its ownership of the WIPP site as a

measure that will identify the site as

Federal property and off limits to

resource exploration.

EPA evaluated whether the proposed

markers are ‘‘as permanent as

practicable’’ by considering the manner

in which DOE accounted for potential

marker failures and by confirming that
58828 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

the proposed markers could be

fabricated. EPA’s analysis of the

proposed markers suggests that they are

practicable, although DOE may decide

to revise the design as implementation

proceeds. Any such revisions would

constitute a modification of the design

and would therefore require EPA

approval in accordance with §§ 194.65

and 194.66. Also, the CCA showed that

the proposed design incorporates

features intended to promote the

endurance of markers. Examples of

these features are: redundant markers,

highly durable materials with low

intrinsic value, large dimensions, and

location both above and below the

surface. EPA proposes to find that the

proposed markers are designed to be as

permanent as practicable, in accordance

with § 194.43(a)(1).

With regard to placement of records,

DOE has prioritized archives and record

centers in order to target those closest to

the WIPP and most likely to be

consulted by resource exploration

industries nationally and abroad. The

additional PICs proposed by DOE,

which involve placement of WIPP

information on maps and in various

reference materials, also appear to be

practicable. Therefore, EPA proposes to

find that DOE complies with

§§ 194.43(a)(2) and (3).

DOE estimated the amount of time

that most of the proposed PICs are

expected to endure by comparing them

to analogues with similar properties that

have survived to the present. The

estimates of endurance, the lowest of

which is at least 2,400 years and the

greatest of which is at least 5,000 years,

vary according to the age of analogues.

DOE estimated the length of time that

messages and records are expected to be

understood (at least 1,000 years) by

making assumptions about the future

and then stating why those assumptions

are reasonable. Because DOE based its

design on sound principles, took into

account likely failures of PICs, based

estimates of endurance on relevant

analogues, and based estimates of

comprehensibility on a reasonable

framework of assumptions, EPA

believes that the proposed design for

markers meets the criterion of ‘‘as

permanent as practicable’’ and that

DOE’s estimates for that purpose are

acceptable for compliance with

§ 194.43(b).

DOE proposed to take most of the

steps necessary for implementing the

proposed PICs, such as making

arrangements with archives and record

centers and refining marker messages,

during the WIPP’s operational period.

However, DOE also plans to extend

some activities, particularly testing of

markers, over nearly 100 years after

closure (i.e., during the proposed active

institutional control period) before

finalizing important aspects of the

design, in the belief that future

technology may improve the design.

EPA cannot base a regulatory

determination that DOE has

demonstrated compliance with the

requirements at § 194.43 on a

speculative plan to finalize the required

design during the active institutional

control period. It would be inconsistent

with Congress’ intent in the LWA for

EPA to allow DOE to alter the approved

PICs design after EPA’s regulatory

function comes to an end.

Rather, EPA’s determination must be

based on the design proposed in the

CCA. EPA acknowledges that future

technological developments might

improve the design of certain PICs

components. Should DOE develop

evidence that aspects of the proposed

design can be improved during the

operational period, DOE could then

request modification of the approved

plan in a recertification application.

DOE also will not be precluded in the

future from implementing other

measures in addition to those

comprising the final design. During the

period that EPA exercises regulatory

oversight over the WIPP, DOE may not

alter or delete aspects of the approved

plan in the CCA without notifying EPA

and subjecting the certification to

modification, if EPA deems it necessary.

Given that EPA considered the design

proposed in the CCA to be final for the

purposes of its compliance review, EPA

finds that DOE has not justified

sufficiently the need for additional

testing of markers after closure of the

repository or the need to delay

implementation for many years after

closure. EPA believes that PICs should

be implemented as soon as possible

after the WIPP facility is sealed, and that

measures necessary to prepare for such

implementation should be

accomplished during the operational

period for the WIPP, unless doing so

would compromise the effectiveness of

the CCA design. For example, EPA

believes that it is appropriate and

practicable during the operational

period for DOE to establish agreements

with national archives to accept and

maintain records related to the WIPP.

EPA therefore proposes to find DOE in

compliance with the PICs requirements

at §§ 194.43(a) and (b), on the condition

that DOE submit additional information

to EPA for approval. No later than the

final re-certification application

submitted prior to closure of the

disposal system, DOE must provide a

schedule for implementing PICs 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

disposal system. DOE also must

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 may be expected

to result from such testing. (See

Condition 4 of the proposed Appendix

A to 40 CFR Part 194.)

DOE proposed to take a credit of 99

percent over 700 years in the PA. In

other words, DOE requested that the

likelihood of human intrusion into the

WIPP during the first 700 years after

closure be reduced to one percent of the

drilling rates calculated in accordance

with the requirements of §§ 194.33(b)(3)

and (4). The proposed credit was based

largely on DOE’s approach to

compliance with § 194.43(b), which led

DOE to conclude that all PICs are

‘‘virtually certain’’ to endure and be

understood for at least 700 years. DOE

identified drilling in the wrong location

on a properly issued lease as the only

plausible scenario whereby the

proposed PICs could fail to deter an

inadvertent intrusion. DOE then

surveyed the Delaware Basin and other

areas for such failures and determined

that wells were drilled in the wrong

location in 5 out of 429,000 instances,

a rate of 0.001 percent. Finally, DOE

bounded the failure rate (of 0.001) at 1.0

percent for the sake of conservatism.

EPA agrees with DOE that the

proposed PICs appear likely to endure

and be understood for hundreds of

years. However, EPA proposes to deny

DOE’s request for PICs credit. The

reasons for EPA’s denial of PICs credit

are discussed briefly below.

First, in promulgating its PICs credit

criterion, EPA explicitly stated that ‘‘the

degree to which PICs might reduce the

future drilling rate can be reliably

determined only through informed

judgment.’’ (61 FR 5232) EPA clearly

expected the proposed PICs credit to be

derived through an expert elicitation

conducted in accordance with the

requirements at 40 CFR 194.26. DOE

instead prepared a justification and

submitted it to peer review. EPA regards

peer review as qualitatively different

from expert judgment, in which the

independent panel itself prepares the

justification.

Second, § 194.43(c) states, ‘‘In no case

. . . shall passive institutional controls

be assumed to eliminate the likelihood

of human intrusion entirely.’’ DOE’s

rationale for the proposed credit

repeatedly states that PICs are ‘‘virtually

certain’’ to eliminate the likelihood of

human intrusion. EPA believes that the
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58829

assertion that PICs are virtually certain

(i.e, 99.9 percent) to endure and be

understood is equivalent in effect to

assuming that they eliminate the

likelihood of human intrusion entirely.

Furthermore, DOE’s estimate of the

effectiveness of PICs does not

adequately account for the considerable

uncertainty associated with quantifying

the effectiveness of PICs for use in the

PA. Specifically, there are potential

failure scenarios that DOE did not

account for in developing the proposed

credit. For example, within the next 700

years, someone could drill based on an

incorrect permit, permits may be

mistakenly granted, records of the WIPP

could be lost, or a system of permits to

control drilling may be abandoned.

While DOE’s proposal does not account

conservatively for uncertainty, EPA

recognizes that any level of credit EPA

would propose in place of DOE’s

estimate would be arbitrary. Finally,

EPA found that the issue of quantitative

credit for PICs is of little consequence

for the purpose of evaluating the WIPP’s

performance, since the removal of PICs

credit from computer models (in the

Performance Assessment Verification

Test) produced no signification effect on

the WIPP’s compliance with EPA’s

numerical standards.

EPA proposes to determine that DOE

complies with § 194.43, on the

condition that additional information on

the final PICs design be submitted for

EPA’s review no later than the final recertification application. For additional

information on EPA’s evaluation of

compliance for § 194.43, see CARD 43.

D. Section 194.44, Engineered Barriers

Section 194.44 requires that DOE

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,

which requires the use of one or more

engineered barriers, 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.

To comply with this requirement,

EPA expected DOE to describe the

engineered barrier(s) selected for

implementation at the WIPP. EPA also

expected the CCA to document how the

engineered barrier(s) prevents or

substantially delays the movement of

water or radionuclides to the accessible

environment, and how it reduces

uncertainties in modeling performance

of the disposal system. EPA expected

DOE to conduct a comprehensive

evaluation of engineered barrier

alternatives in order to compare the

benefits and detriments of various

barriers and then use the results of such

a comparison to justify selecting or

rejecting a barrier(s).

In accordance with § 194.44(b), EPA

observed DOE’s scoping study and

screening process during March and

April 1995. The scoping effort produced

a list of 111 potential barriers and

combinations of barriers (including the

barriers described in § 194.44(b)), of

which 18 were evaluated against the

factors described in § 194.44(c).

Although DOE did not specifically

address the waste categories in

§ 194.44(d), the study effectively

accounted for the categories by

analyzing three waste types (sludges,

solid organics, and solid inorganics) and

considering multiple waste processing

schemes. DOE’s evaluation of

engineered barriers was peer reviewed

in accordance with § 194.27(a)(3). See

§ 194.27, ‘‘Peer Review,’’ for details of

EPA’s evaluation of the general peer

review process. On the basis of its

evaluation of the benefits and

detriments of eighteen engineered

barrier types, DOE concluded that a

chemically-buffering backfill was a

high-benefit, low-cost, and practicable

engineered alternative. DOE selected

magnesium oxide (MgO) backfill as an

engineered barrier, and proposed to

emplace bags of MgO between and

around waste containers in the

repository. DOE stated that the backfill

will serve to: (1) substantially delay

movement of radionuclides by

controlling chemical conditions in the

underground waste panels so that the

solubility of radionuclides in water is

reduced, (2) delay movement of water

by reacting with brine to reduce free

water in the disposal system, and (3) fix

pH levels within a narrow range,

thereby bounding an important

modeling parameter whose value might

otherwise be highly uncertain.

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. DOE provided substantial

documentation in the CCA and

supplementary information that MgO

can effectively reduce actinide

solubility in the disposal system. EPA

agrees that the chemical reactions that

DOE associated with MgO can occur

under predicted repository conditions.

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. (For

details regarding chemical reactions of

MgO, see CARD 24, ‘‘Waste

Characterization.’’ For further

information regarding the PA modeling

of solubility and chemical conditions in

the repository, see CARD 23, ‘‘Models

and Computer Codes.’’)

Public comments received on EPA’s

Advance Notice of Proposed

Rulemaking (‘‘ANPR’’) questioned two

aspects of DOE’s treatment of

engineered barriers in the CCA. First,

commenters disagreed that borehole

plugs, shaft seals, and panel seals

should be treated by DOE as engineered

barriers for the purpose of complying

with § 194.44. EPA found that DOE had

treated plugs and seals as part of the

baseline design of the disposal system,

not as additional barriers for the

purpose of assurance. The effectiveness

of plugs and seals is discussed as part

of EPA’s evaluation of the disposal

system design under § 194.14, ‘‘Content

of Compliance Certification

Applications.’’ Second, commenters

expressed concern that the CCA did not

support conclusions about the

effectiveness of MgO with experimental

data or other documentation. EPA

shared this concern and so requested

that DOE provide additional

documentation showing that backfill

could be emplaced in the required

manner and would function in the

disposal system as proposed. EPA

believes that supplementary information

sent by DOE adequately addressed

insufficiencies in the CCA.

EPA proposes to find DOE in

compliance with § 194.44. For further

information on EPA’s evaluation of

compliance for § 194.44, see CARD 44.

E. Section 194.45, Consideration of the

Presence of Resources

Section 194.45 implements the

assurance requirement that the disposal

system be sited such that the benefits of

the natural barriers of the disposal

system compensate for the increased

probability of disruptions to the

disposal system resulting from

exploration and development of existing

resources. (61 FR 5232) In promulgating

this requirement, EPA determined that

the performance assessment (‘‘PA’’) is

the appropriate tool to weigh the

advantages and disadvantages of the

WIPP site because PA demonstrates

whether potential human intrusion will

cause unacceptably high releases of

radioactive material from the disposal

facility.
58830 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

In accordance with the Compliance

Criteria, DOE must demonstrate that PA

has incorporated the potential effects of

human activities near the WIPP prior to

disposal, and of drilling and excavation

mining over the regulatory time frame.

DOE also must document that the

results of the PA demonstrate

compliance with the containment

requirements at 40 CFR 191.13. No

further demonstration of compliance is

needed for § 194.45.

The Agency confirmed that PA

incorporated human intrusion scenarios

and met EPA’s release limits in

accordance with the WIPP Compliance

Criteria. Based on EPA’s findings that

DOE complied with requirements

related to scope of PA, conduct of PA,

mining and drilling activities over the

regulatory time frame, results of PA, and

pertinent assurance requirements, EPA

proposes to determine that DOE has

demonstrated compliance with § 194.45.

For further explanation of EPA’s

proposed compliance decisions for

these related compliance criteria, see

preceding preamble discussions for

§ 194.14, § 194.23, § 194.32, § 194.33,

§ 194.34, § 194.41, and § 194.43. For

further information on EPA’s evaluation

of compliance for § 194.45, refer to

CARD 45.

F. Section 194.46, Removal of Waste

Section 194.46 requires

documentation that the removal of

waste from the disposal system is

feasible for a reasonable period of time

after disposal. (61 FR 5244) The intent

of this provision is to implement the

assurance requirement at 40 CFR

191.14(f) that ‘‘disposal systems be

selected so that removal of most of the

waste is not precluded for a reasonable

period of time after disposal.’’ To meet

the criteria of § 194.46, EPA expected

the CCA to provide a comprehensive

strategy that showed the manner in

which waste could be removed from the

repository for a reasonable period of

time after closure and an estimate of

how long after disposal removal of

waste would remain technologically

feasible. Although the eventual

disposition of the waste is an important

environmental concern, 40 CFR Part 194

does not require DOE to speculate on

the possible location or hazards of the

waste once it is removed from the

repository.

In the CCA, DOE presented a fivephase approach to removing waste from

the WIPP repository, including:

planning and permitting; initial aboveground set-up and shaft sinking;

underground excavation and facility setup; waste location and removal

operations; and decontamination and

decommission of the facility. The CCA

included a discussion of techniques that

could be used to remove the waste given

the repository conditions at the time of

removal, and also discussed several

existing mining techniques that could

be used to remove waste from the WIPP

repository.

EPA reviewed the CCA to assess the

completeness of the strategy for

removing the waste and the justification

of the proposed technology for removing

the waste. EPA believes that the five

phases described for waste removal

provide an orderly sequence of planning

and implementation procedures that

could be implemented. EPA agrees that

the proposed activities, techniques, and

equipment that would be necessary to

remove the waste are all presently

feasible.

EPA reviewed the CCA for an estimate

of how long after disposal it would

remain technologically feasible to

remove the waste. DOE stated that,

using the system and equipment

proposed in the CCA, it would be

feasible to remove the waste any time

after emplacement. Thus, DOE appeared

to conclude that no features of the

disposal system (such as salt creep) will

prevent the removal of waste from the

repository as long as the technology

described in the CCA remains available.

The CCA did not address how long the

technology might remain available.

EPA agrees that waste removal would

be feasible as long as current technology

remains available, but does not believe

it is reasonable to assume that the

technology will remain available over

the entire regulatory time frame. To

estimate the length of time for which

waste removal would be feasible, EPA

considered how long the technology

described in the CCA might remain

available. The Agency concluded that,

as long as our present society remains

stable, it is reasonable to conclude that

there will likely be a continuity or

advancement of technology which

would allow waste removal to occur. In

the disposal regulations, EPA identified

100 years after disposal as a realistic but

conservative limit on how long active

controls could be assumed to be

effective—i.e., how long present

institutions would remain in place

continuously to enforce such controls.

(50 FR 38080) Based on this same

rationale, EPA believes it is reasonable

to assume that current technology will

remain available for the 100-year period

after disposal, and therefore that waste

removal will remain feasible for that

time. EPA believes that 100 years

constitutes a reasonable period of time

after disposal, in accordance with

§ 194.46. Therefore, EPA concludes that

DOE has met the regulatory

requirements for the removal of waste,

and proposes to find DOE in compliance

with § 194.46. For further information

on EPA’s evaluation of compliance for

§ 194.46, see CARD 46.

XIII. Individual and Ground-water

Protection Requirements

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 radiation dose limits and

radionuclide concentration limits for

ground water is conducted through use

of a process known as compliance

assessment (‘‘CA’’). Compliance

assessments use methods similar to

those of PA (for the containment

requirements) but are required to

address only undisturbed performance

of the disposal system. Sections 194.51

and 194.52 specify the requirements

which must be incorporated into CA in

the analyses of individual radiation

doses to protected individuals. Section

194.53 addresses underground sources

of drinking water. Finally, the criteria

specify the scope of CA and establish

statistical requirements on the results of

CA in demonstrating compliance with

the individual and ground-water

protection requirements (§§ 194.54 and

194.55).

A. Section 194.51, Consideration of

Protected Individual

Section 194.51 requires DOE to

assume in compliance assessments

(‘‘CA’’) that an individual resides at the

point on the surface where the dose

from radionuclide releases from the

WIPP would be greatest. 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.

DOE’s analysis of the WIPP’s

compliance with § 194.51 and related

sections of the Compliance Criteria was

contained in the CCA and in

supplementary information. DOE

described its analysis as a ‘‘bounding

analysis’’ because it assumed that the

maximum concentration of

radionuclides was available in

underground sources of drinking water

(‘‘USDWs’’) and that humans using that

water would therefore receive the

maximum dose possible from that

pathway.

The bounding analysis was derived

from the performance assessment for the

undisturbed scenario. DOE analyzed all

potential routes of release of radioactive
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58831

waste from the repository that could

lead to exposure of an individual and

determined that the only release to the

accessible environment would be

passage of contaminated water through

the interbeds in the Salado Formation,

where the WIPP is situated. In the

analysis, DOE demonstrated that

radionuclides migrated horizontally to

the accessible environment in only nine

out of 300 realizations.

DOE then assumed that the highest

concentration of radionuclides from the

nine realizations was present at the

subsurface boundary of the accessible

environment, and that individuals

would take water for consumption or

agricultural use directly from this

location in the Salado. DOE stated that

it was not necessary to identify a single

point of maximum dose because the

analysis assumed that the maximum

radionuclide concentration was

available to individuals in brine taken

from the Salado Formation; therefore,

the dose from various pathways would

be maximized regardless of an

individual’s location on the surface of

the accessible environment. For more

discussion of DOE’s consideration of

pathways in the bounding analysis, see

§ 194.52, ‘‘Consideration of Exposure

Pathways.’’

EPA agrees that it was conservative

for DOE to base its calculations of

individual dose on the maximum

predicted radionuclide concentrations.

EPA also accepts as technically sound

DOE’s rationale for not identifying a

single geographic point at which

individual committed effective dose is

greatest, since under DOE’s

assumptions, all points on the surface

would result in the same maximum

dose. Therefore, EPA proposes to find

DOE in compliance with § 194.51. EPA

discusses whether the results of DOE’s

dose calculations comply with the

individual protection requirements at 40

CFR 191.15 under the evaluation for

§ 194.55, ‘‘Results of CA.’’ Due to the

relatedness of the requirements, EPA

combined the discussion of DOE’s

compliance for §§ 194.51 and 194.52

(‘‘Consideration of Exposure Pathways’’)

in a single Compliance Application

Review Document (CARD 51/52).

B. Section 194.52, Consideration of

Exposure Pathways

The individual protection

requirements focus on the annual

radiation dose of a hypothetical

maximally-exposed person living on the

surface just outside the boundary to the

accessible environment. Section 194.52

requires DOE’s compliance assessments

for the individual protection

requirements to consider all potential

exposure pathways for radioactive

contaminants from the WIPP. DOE must

assume that an individual consumes 2

liters per day of drinking water from any

underground source of drinking water

in the accessible environment. EPA

expected that DOE would postulate

several release pathways and calculate

the dose resulting from each pathway.

In the CAG, EPA stated that DOE could

employ simplified exposure models

provided that DOE showed them to be

more conservative than more detailed

models. (CAG, pp. 67–68)

DOE’s modeling identified only one

possible release of radionuclides to the

accessible environment for the

undisturbed performance scenario,

resulting from contaminated brine

flowing through the Salado Formation

interbeds. DOE’s modeling indicated

that this release could occur if there

were a significant buildup of gas and

fluid pressure within the WIPP’s waste

panels.

To assess this potential exposure

pathway, DOE conservatively assumed

that Salado brine would be available for

human use once it reached the

subsurface boundary of the accessible

environment. Water in the Salado

interbeds is actually a highly

concentrated brine unsuitable for

drinking; DOE has measured the average

concentration of total dissolved (nonradioactive) solids (‘‘TDS’’) in Salado

brine as 324,000 milligrams per liter

(mg/L). DOE therefore assumed that

brine would have to be diluted with

pure water in order to bring the

concentration of TDS down to the

highest allowable amount under the

standard for potable water (10,000

mg/L TDS). DOE assumed that this

diluted Salado brine would be

consumed at the rate of two liters per

day and then calculated the dose

resulting from this single pathway of

water ingestion.

EPA required DOE to expand its

analysis to include additional pathways.

This expanded analysis is described in

supplementary information sent by

DOE. (Docket A–93–02, Item II-I–10)

DOE examined pathways whereby

humans either inhale dust from soil

irrigated with contaminated water or

consume agricultural products irrigated

with contaminated water. In the latter

case, pathways included plants eaten

directly by humans and milk or beef

from cattle whose stock pond contained

contaminated water.

Based on the CCA and the

supplementary information described

above, EPA found that DOE assumed in

its analysis of pathways that individuals

consume 2 liters per day of water from

underground sources. EPA also

conducted independent calculations

and concluded that DOE had reliably

reported the doses expected to result

from all pathways considered. EPA

discusses whether the results of DOE’s

dose calculations comply with the

specific requirements of 40 CFR 191.15

under 194.55, ‘‘Results of Compliance

Assessments.’’

EPA found that the simplified

‘‘bounding analysis’’ employed by DOE

(described under § 194.51 above) was

sufficiently conservative not to require

the use of more detailed models. The

bounding analysis was conservative

because it assumed unrealistically that

brine in the Salado Formation would be

used as a source of water for drinking

and irrigation. In fact, brine in the

Salado is not likely to be used as an

underground source of drinking water

because it has an extremely high

concentration of TDS. Salado brine

would require considerable dilution in

order to meet the criteria for potable

water, and dilution would serve to

reduce radionuclide concentrations.

There are other, more likely sources of

water than the Salado in the vicinity of

the WIPP (see § 194.53 below), but

DOE’s modeling demonstrated that

radionuclides from the WIPP would not

reach these sources in the undisturbed

scenario.

EPA therefore proposes to find the

WIPP in compliance with § 194.52. Due

to the relatedness of the requirements,

EPA combined the discussion of DOE’s

compliance with §§ 194.51

(‘‘Consideration of the Protected

Individual’’) and 194.52 in a single

Compliance Application Review

Document (CARD 51/52).

C. Section 194.53, Consideration of

Underground Sources of Drinking Water

Section 194.53 requires that

compliance assessments of the

undisturbed performance scenario

consider underground sources of

drinking water (‘‘USDWs’’) near the

WIPP and their interconnections. The

undisturbed scenario assumes that the

disposal system will not be disturbed by

human activities such as drilling or

mining. 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) supplies drinking

water for human consumption or (ii)

contains fewer than 10,000 mg per liter

of total dissolved solids.’’

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
58832 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

they in fact meet the regulatory

definition of a USDW. However, DOE

did not identify a plausible release

scenario in undisturbed conditions in

which radionuclides from the WIPP

reached these potential USDWs. DOE

found instead that the only plausible

release scenario in undisturbed

conditions involved transport of

radionuclides by brine laterally through

the Salado Formation (where the WIPP

is situated) to the subsurface boundary

of the accessible environment. The

concentration of radionuclides at the

subsurface boundary in this scenario

represents the maximum level possible

in the accessible environment.

DOE assumed that brine at the

subsurface boundary would be directly

available to a hypothetical individual on

the surface for use as drinking water. In

other words, DOE assumed that people

would draw water directly from the

Salado, thereby bypassing other

potential USDWs, and would thus be

exposed to the maximum concentration

of radionuclides. Because DOE assumed

the worst-case scenario and did not

attempt to demonstrate in the analysis

that transport of radionuclides through

geological formations in the accessible

environment would lower their

concentrations, DOE concluded that it

was not necessary to analyze

underground interconnections among

water bodies.

EPA agrees that the Culebra, Santa

Rosa, and Dewey Lake Formations are

the most likely potential USDWs. Also,

EPA agrees that it was not necessary to

identify USDW interconnections

because of DOE’s conservative

assumption that individuals, regardless

of their location on the surface of the

accessible environment, would be

exposed to the maximum available

concentration of radionuclides in

drinking water.

Based on information provided in the

CCA, EPA concluded that DOE

adequately considered USDWs in

compliance assessments. EPA therefore

proposes to find that DOE complies

with § 194.53. EPA discusses whether

the results of DOE’s calculations comply

with the requirements of § 191.15 and

Subpart C of 40 CFR Part 191 in

§ 194.55, ‘‘Results of CA.’’ For further

discussion of EPA’s evaluation of

compliance for § 194.53, see CARD 53.

D. Section 194.54, Scope of Compliance

Assessments (CA)

Section 194.54 addresses the scope of

compliance assessments (‘‘CA’’)

conducted to determine compliance

with the individual dose and groundwater protection requirements of the

disposal regulations. The CA must

account for the undisturbed

performance of the disposal system; that

is, the predicted behavior of the

disposal system if it is not disrupted by

human intrusion or the occurrence of

unlikely natural events (§ 191.12). As

with performance assessment, the CA

must consider features, events, and

processes (‘‘FEPs’’) and associated

uncertainties. The CA can be considered

a ‘‘subset’’ of performance assessment,

as CA considers only natural/

undisturbed conditions and past/nearfuture human induced activities, but

does not include long-term future

human-induced activities that are

included in performance assessment.

EPA required DOE to consider FEPs

that relate to undisturbed performance

of the disposal system. EPA required

DOE to identify how these FEPs were

screened, combined, and used in the

CA. DOE was required to document why

any undisturbed scenario FEPs were not

included in the CA. EPA also required

the CA to consider activities that occur

in the vicinity of the WIPP and their

effect on radionuclide migration from

the site. Specifically, DOE was required

to consider existing boreholes and near

future lease development.

To fulfill the requirements of

§ 194.54(a), DOE developed and

followed a process for considering FEPs

in the CA. Out of the initial list of

approximately 72 natural FEPs, DOE

eventually included 17 in the CA. This

is the same process that was used in

identifying FEPs for PA; EPA’s

evaluation of the process is addressed in

the preamble discussion of § 194.32.

EPA concluded that the initial FEP list

assembled by DOE was sufficiently

comprehensive, in accordance with the

requirements of § 194.54(a). This list

appropriately screened out events and

processes on the basis of probability,

consequence or regulatory requirements.

DOE considered and incorporated into

CA numerous natural processes and

events. DOE adequately documented the

decision not to include FEPs in the CA.

(See preamble discussion for § 194.32.)

DOE, in accordance with the

requirements of § 194.54(b), conducted

an analysis of the activities that are

expected to occur in the vicinity of the

WIPP in the near future. DOE’s

assessment of existing boreholes

indicated that natural fluid flow through

abandoned boreholes would be of very

little consequence in the near future and

was therefore not included in the CA. In

addition to existing boreholes, DOE

addressed a number of activities that

could occur in the vicinity of the WIPP

in the near future. These activities were:

oil and gas exploration, exploitation and

extraction; potash exploration and

exploitation; fluid injection related to

oil and gas production; sulfur coreholes;

hydrocarbon/gas storage; brine wells for

solution mining; and water supply

wells. DOE determined that none of

these activities will have an impact on

the disposal system in the near future

and therefore did not include them in

the CA. DOE examined fluid injection

for inclusion in the CA, but screened it

out based on low consequences to the

disposal system if it happened. DOE

also provided information on leases in

the WIPP area.

EPA reviewed the CCA analysis of

existing boreholes in the vicinity of the

WIPP and their potential impact on

radionuclide migration and agrees with

DOE’s conclusion that existing

boreholes will not affect the disposal

system. EPA and public commenters

disagreed with DOE’s initial analysis of

the effects of fluid injection and salt

water mining. Upon reviewing

supplemental modeling of these

scenarios, conducted by DOE and also

independently by EPA, EPA agrees that

these activities were correctly omitted

from the CA. (See the preamble for

§ 194.32 for further discussion of this

additional modeling.) DOE satisfactorily

identified leases near the WIPP and

appropriately estimated the life of the

leases for consideration in the CA.

EPA proposes to find DOE in

compliance with the requirements of

§ 194.54. For further information on

EPA’s evaluation of compliance for

§ 194.54, see CARD 54.

E. Section 194.55, Results of CA

Section 194.55 establishes

requirements for analyzing the WIPP’s

compliance with the individual and the

ground-water protection requirements of

the disposal regulations. These

requirements: (1) limit the possible

radiation dose from the WIPP to

individuals in the accessible

environment, and (2) limit the degree of

radioactive contamination of

groundwater for which the WIPP might

be responsible. Both limitations are

required to be analyzed for undisturbed

performance of the disposal system for

10,000 years. (See the discussion for

§ 194.54 in today’s preamble.)

40 CFR 191.15, the individual

protection requirements, requires that

there must be a reasonable expectation

that undisturbed performance of the

WIPP disposal system will not cause the

annual committed effective dose

equivalent to exceed 15 millirems (150

microsieverts) to any member of the

public in the accessible environment.

Subpart C of 40 CFR Part 191, the

ground-water protection requirements,

sets requirements on the radiation levels
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58833

in underground sources of drinking

water (‘‘USDWs’’) by referencing the

standards of the Safe Drinking Water

Act at 40 CFR Part 141. In order to

determine compliance with these

requirements, DOE must calculate the

maximum individual radiation dose

from all pathways, the maximum

concentrations of specific radionuclides

in any USDW, and the maximum annual

dose equivalents from radioactivity in

any USDW.

Section 194.55 establishes six

requirements for computing, presenting,

and evaluating the results of compliance

assessments (‘‘CA’’). The requirements

of §§ 194.55(b) through (f) are analogous

to the requirements of §§ 194.34(b)

through (f) for the results of

performance assessment (‘‘PA’’). As a

result, DOE has been able to use the

same computational techniques and the

same computer codes to perform both

PA and CA. The major differences

between the analyses for PA and CA are

that: (1) CA considers only undisturbed

performance of the WIPP, and thus does

not consider scenarios of human

intrusion; (2) CA requires calculations

of doses and radioactivity

concentrations in USDWs, as well as

cumulative releases; and (3) CA results

are expressed as a set of dose and

concentration values, while PA results

are expressed as a series of

complementary cumulative distribution

function (‘‘CCDF’’) curves.

1. Uncertainty of CA

Section 194.55(a) requires the CA to

consider and to document uncertainty

in the performance of the disposal

system. There are two general sources of

such uncertainty. The first is the

uncertainty associated with physical,

chemical and geologic conditions

within and around the repository. The

CA deals with this by running 300

different undisturbed-site scenarios,

with 300 independent sets of sampled

values for the most important uncertain

parameters (i.e., parameters either that

vary from place to place or that simply

are not known with precision, but

which have been determined to have a

significant effect on the WIPP’s ability

to contain radionuclides). The second

source of uncertainty is the lack of

detailed knowledge of the ways in

which contaminated ground water

might be pumped out and utilized by

persons living near the site in the future.

DOE handles this uncertainty through a

conservative bounding calculation on

individual doses, which is intended to

demonstrate compliance regardless of

any uncertainties. The bounding

calculation is discussed in further detail

in the discussions of §§ 194.51 and

194.52 in this preamble.

DOE evaluated uncertainty in the

amount of contaminants transported

underground using the same method as

in the PA, except that uncertainty from

human intrusion scenarios was not

considered. For further information on

the treatment of uncertainty in PA, see

the discussion of § 194.34 in today’s

preamble. EPA found that the

conservative bounding calculation is

appropriate, in lieu of further

uncertainty analysis, and that DOE’s

treatment of uncertainty in CA is

sufficient. Therefore, the Agency

proposes to find that WIPP complies

with § 194.55(a).

2. Probability Distributions for

Uncertain Parameters

Section 194.55(b) requires DOE to

develop and document probability

distributions for uncertain disposal

system parameter values used in CA.

This is similar to the requirement for

parameter values used in the PA. DOE

uses the same probability distributions

for uncertain disposal system parameter

values in both PA and CA calculations.

This involves performing calculations

with 300 independent sets of sampled

parameter values for each of the 57

important parameters associated with

uncertain physical, chemical and

geological conditions in the repository

and its surroundings. EPA conducted

the same evaluation of probability

distributions for CA as for PA.

Upon reviewing DOE’s models and

computer codes, the Agency questioned

a number of important input parameter

values and distributions used in the PA

and in CA. EPA determined that

corrections were necessary for certain

input parameters and conceptual

models. Because of concerns that the

necessary corrections to these

parameters and conceptual models

could have significant effects on the

actual results of modeling, EPA required

DOE to demonstrate that the combined

effect of all the parameter and computer

code changes required by EPA was not

significant enough to necessitate a new

PA. EPA required DOE to perform 300

simulations in additional PA and CA

calculations as a Performance

Assessment Verification Test (‘‘PAVT’’).

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. CA results of the

PAVT are discussed below for

requirement § 194.55(f) and PA results

of the PAVT are discussed above in

§ 194.34 of this preamble. The PAVT

results confirmed that the original PA is

sufficiently conservative and indicated

that further PA and CA analysis is not

required.

After considerable analyses, including

the PAVT, EPA was satisfied that the

parameter values and distributions were

adequate for determining compliance.

See the discussion of the requirements

of § 194.34 of this preamble. For the

reasons discussed in that section, EPA

also proposes to find the CCA in

compliance with § 194.55(b).

3. Sampling of Uncertain Parameters

Section 194.55(c) requires CA to use

computational techniques which draw

random samples from across the entire

range of probability distributions of

uncertain parameters. These

computational techniques then must be

used to calculate the ranges of estimated

radiation doses to individuals received

from all pathways; radionuclide

concentrations in USDWs; and radiation

doses received from USDWs. This

requirement is parallel to § 194.34(c),

which requires techniques for random

sampling from parameter distributions

in the computation of CCDF curves for

the results of PA.

The statistical technique that DOE

used in selecting parameter values in

PA, Latin Hypercube Sampling (‘‘LHS’’),

is also employed in the calculations of

radionuclide concentrations in ground

water (which are then used to calculate

individual doses) for the CA. The CA

generated 300 values of contaminant

concentrations in ground water (at the

boundary to the accessible environment)

and individual annual radiation doses

to assess compliance with § 194.55.

EPA found the LHS technique for

drawing samples randomly from

probability distributions of uncertain

parameters to be sufficient, as discussed

in this preamble for § 194.34. In

addition, EPA determined that DOE’s

conceptual model for determining

maximum individual exposure and the

GENII-A computer code used to

calculate radiation doses were adequate.

The Agency found that DOE has used an

appropriate computational technique,

LHS, for sampling widely from the

parameter distributions described in

§ 194.55(b), and has used it to generate

ranges of radionuclide concentrations in

USDWs, doses from the ingestion of

water from USDWs, and all-pathways

doses. Therefore, EPA proposes to find

that DOE has demonstrated compliance

with § 194.55(c).

4. Sufficient Number of Estimates

Generated

Section 194.55(d) requires that the

number of estimates of radionuclide

concentrations in USDWs, doses from
58834 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

24The Agency agrees with DOE that

concentrations of less than 10¥18 curies per liter are

negligibly small. Such small concentrations found

in the analysis could be due to calculational error

rather than true indicators of radioactive

contamination of USDWs.

the ingestion of water from USDWs, and

all-pathways doses must be large

enough such that the maximum

estimates of doses and concentrations

generated exceed the 99th percentile of

the population of estimates with at least

0.95 probability. This requirement is

similar to the requirement of § 194.34(d)

for determining if there is a sufficient

number of CCDF curves in PA analysis.

Both requirements have the purpose of

ensuring that enough simulations are

generated so that conclusions drawn

from their analyses are statistically

justified.

DOE produced 300 CA calculations

and used the same statistical arguments

to justify both the number of

calculations for CA and the number of

CCDF curves. See the discussion for

§ 194.34 in this preamble for a further

explanation of DOE’s justification and

EPA’s review. EPA found that, for

random sampling, 300 individual

estimates will provide 0.95 probability

that at least one of them will exceed the

population 99th percentile value. Thus,

EPA proposes to determine that the CCA

satisfies the requirement of § 194.55(d).

5. Display full range of CA results

Section 194.55(e) requires the CCA to

display the full range of estimated

radiation doses and radionuclide

concentrations. Section 194.34(e) has a

parallel requirement for displaying the

full range of CCDFs generated.

DOE’s CA analysis of individual doses

started with the findings of the PA of

contamination that has migrated to the

accessible environment in the anhydrite

interbeds immediately surrounding the

repository in the case of an undisturbed

repository. This analysis generated a full

range of radionuclide concentrations in

the ground water. DOE found that only

nine of the three hundred estimates

were not negligibly small (that is, less

than 10¥18 curies/liter) 24. Starting with

the concentrations in the interbeds, DOE

conducted bounding calculations on

individual dose, both from the ingestion

of drinking water and from all exposure

pathways combined. These calculations

adopted assumptions that resulted in

upper-bound estimates of dose that are

much greater than what any individual

might reasonably be expected to receive.

DOE performed this bounding

calculation in lieu of providing

descriptive statistics for the estimates

such as mean, median and standard

deviation, as stated in EPA’s

‘‘Compliance Application Guidance for

the WIPP’’ (‘‘CAG’’). The criteria and the

CAG allow the use of a bounding

calculation as long as the simplified

model is more conservative than more

detailed and more complex modes.

(CAG, p. 68)

EPA reviewed the CCA and found that

DOE performed a full range of the

necessary calculations to demonstrate

compliance with § 191.15 and Subpart C

of 40 CFR Part 191. EPA independently

estimated and tabulated the all-pathway

and USDW doses in a dose verification

analysis. EPA’s results generally agreed

with those of the DOE analysis,

although EPA found DOE’s calculations

to be conservative. EPA calculated

descriptive statistics such as the mean

and the 95 percent confidence interval

for doses and concentrations to provide

added assurance of the adequacy of

DOE’s methodology. Because the CCA

presents specific estimates for each of

the non-zero simulations or the upper

bound estimate for those simulations

and presents the full ranges of

radionuclide concentrations and

radiation doses, EPA proposes to find

that DOE has demonstrated compliance

with § 194.55(e).

6. Compliance With Radiation Dose and

Radionuclide Concentration Limits

Section 194.55(f) requires the CCA to

document that there is at least a 95

percent level of statistical confidence

that the mean and the median of the

range of estimated radiation doses and

the range of estimated radionuclide

concentrations meet the requirements of

§ 191.15 and Subpart C of 40 CFR Part

191. This requirement is analogous to

§ 194.34(f), which requires at least a 95

percent level of statistical confidence

that the mean of the population of

CCDFs meets the containment

requirements of § 191.13. In order to

meet this requirement, it is necessary to

calculate the lower and upper limits of

the range, the mean, and the median of

the estimated doses and of the

radionuclide concentrations.

The limit for individual doses in

§ 191.15 is an annual committed

effective dose, from all pathways, of 15

mrem/year. The limits for doses and

radionuclide concentrations in USDWs

under Subpart C of 40 CFR Part 191 are

a total radioactivity concentration for

radium-226 and radium-228 in any

USDW of 5 picocuries per liter of water

(pCi/L); a gross alpha particle

radioactivity (including radium-226 but

excluding radon and uranium) in any

USDW of 15 pCi/L; and an annual dose

equivalent to the total body or any

internal organ from beta particle and

photon radioactivity in any USDW of 4

mrem/year. DOE calculated a maximum

annual committed effective dose

equivalent from exposure through all

pathways of 0.93 mrem/year. The CCA

reported that the maximum estimated

radium concentration in ground water is

2.0 pCi/L. The CCA contained the 300

estimated concentrations for the five

radionuclides 241Am, 239Pu, 238Pu, 234U, and 230Th, and only nine of these

were not negligibly small. The CCA

reported the maximum gross alpha

particle concentration as 7.81 pCi/L

from 241Am, 239Pu, 238Pu, 230Th and

all isotopes of Ra. DOE used its

bounding calculation for dose due to all

radionuclides from drinking USDWs to

show that the annual dose equivalent to

the whole body from beta particle and

photon radioactivity would be no more

than 0.47 mrem/year. Supplemental

analyses conducted by DOE also

showed that the maximum beta particle

and photon dose equivalent to any

internal organ was well below the 4

mrem/year regulatory limit; bone

surface was identified as the critical

organ for that calculation. The

maximum estimate concentration or

dose for each of these is less than the

standard. Because the maximum value

for each of these values was less than

the applicable standard, and because the

bounding analysis accounted for sources

of uncertainty, DOE concluded that the

mean, median and 95 percent

confidence interval values also met the

standards of § 191.15 and Subpart C of

40 CFR Part 191.

EPA commissioned an independent

analysis to verify DOE’s dose

calculations. In general, EPA’s analysis

calculated values similar to those

calculated by DOE. EPA also calculated

the mean, median and 95 percent

confidence intervals of concentrations

and doses. EPA’s analysis confirmed

that the mean and median values are in

compliance with the requirements of

§ 191.15 and Subpart C of Part 191.

The PAVT computed thirteen

simulations with non-negligible

concentrations of radionuclides in

ground water, compared with nine in

the CCA CA. All of these thirteen

simulations computed doses of less than

1 mrem/year, compared to the standard

of 15 mrem/year for individuals. PAVT

calculations also demonstrated that the

doses to internal organs and from beta

particle and photon radiation in ground

water were several orders of magnitude

less than the standard. Thus, PAVT

results indicated that the mean and

median dose values and ground-water

concentrations will meet the

requirements of § 191.15 and Subpart C

of Part 191.
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58835

Based on the CCA, supplementary

documentation provided by DOE, and

the Agency’s independent studies, EPA

has determined that there is at least a 95

percent level of statistical confidence

that the mean and the median of the

range of estimated radiation doses and

the range of estimated radionuclide

concentrations meet the requirements of

§ 191.15 and Subpart C of 40 CFR Part

191. Therefore, EPA proposes to find

that DOE has demonstrated compliance

with § 194.55(f). For further information

on EPA’s evaluation of compliance for

§ 194.55, see CARD 55.

XIV. Land Withdrawal Act Section

4(b)(5)(B) Leases

The 1992 WIPP Land Withdrawal Act

(‘‘LWA’’) (Public Law 102–579)

withdrew the geographical area

containing the WIPP facility from all

forms of entry, appropriation, and

disposal under public land laws. The

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. Further, the LWA

established responsibilities for DOE to

manage the land withdrawal area and

required submittal of a management

plan for that purpose. Under DOE’s

management plan, all surface or

subsurface mining or oil or gas

production is prohibited at all times on

lands on or under the withdrawal area.

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

LWA exempted, from the prohibition on

oil and gas production, two leases

already in existence. Section 4(b)(5)(B)

states that the existing rights under the

two oil and gas leases (Nos. NMNM

02953 and 02953C) (hereafter, ‘‘the

section 4(b)(5)(B) leases’’) shall not be

affected unless the Administrator

determines, after consultation with DOE

and the Department of Interior, that the

acquisition of such leases by DOE is

required to comply with EPA’s final

disposal regulations at 40 CFR Part 191,

Subparts B and C. Before DOE can

emplace waste in the WIPP, DOE must

either acquire the leases or the EPA

must determine that such acquisition is

not required. (LWA, section 7(b)(2))

In 1977, DOE purchased the leases in

the land withdrawal area between the

surface and 6,000 feet (1829 meters)

below the surface. Since DOE owns all

land rights down to 6,000 feet, no

drilling is permitted from the surface of

the LWA leases. Any drilling that takes

place on the LWA section 4(b)(5)(B)

leases must therefore be slant drilling

that is initiated from outside the land

withdrawal area. Oil and gas resources

in the southwest area of the site, where

the section 4(b)(5)(B) leases are located,

are expected to occur below 6000 feet

down to approximately 16,000 feet.

The EPA’s determination of whether

the section 4(b)(5)(B) leases must be

acquired by DOE depends on an

evaluation of drilling activities very

similar to that conducted by DOE for

performance assessment (‘‘PA’’) related

to the containment requirements at 40

CFR 191.13. In fact, § 194.32(c) of the

WIPP Compliance Criteria requires DOE

to analyze the effects of any activities

that occur in the vicinity of the disposal

system prior to or soon after disposal,

including the ‘‘development of any

existing leases.’’ Therefore, in its

examination of the effects of the section

4(b)(5)(B) leases, EPA relied on the

closely related PA analyses conducted

by DOE for the purpose of compliance

with § 194.32(c).

For an oil or gas well, the potential

life cycle may consist of: drilling;

resource recovery (production); fluid

injection for enhanced secondary

production (either by waterflooding

techniques or injection to maintain oil

reservoir pressure); reinjection of waste

fluids for disposal; and abandonment. In

the PA for the compliance certification

application (‘‘CCA’’), DOE conducted

several analyses to identify the potential

effects of these activities on the disposal

system, with the exception of

production, which is exempted from

consideration by regulation

(§ 194.33(d)). EPA examined each of

DOE’s analyses in its evaluation for the

section 4(b)(5)(B) leases.

In its analyses for the PA, DOE

concluded that the drilling of a deep

well would adversely affect the disposal

system only if the borehole intersected

a waste panel in the underground

portion of the WIPP. Drilling is of

concern if the borehole penetrates the

waste, and forces it to the surface, or

allows a pathway for long-term

transport of radionuclides. EPA agrees

that the effects of drilling a borehole—

and similarly, the effects of resource

recovery (oil or gas production)—would

be highly localized, for several reasons.

Current oil and gas production drilling

in the area near the WIPP site includes

well casing procedures and borehole

plugging practices that would mitigate

the potential impact of future drilling

activities. Wells drilled in the Delaware

Basin (which encompasses the entire

land withdrawal area) include at least

two sets of steel casing lining the

borehole (deeper wells use three sets of

steel casing). Also, production and

injection wells contain an additional set

of tubing used to produce the oil or gas,

or to inject fluid into the well. Present

day practice would require multiple

failures in these steel casings and

tubings to cause any flow from the oilor gas-producing zone towards the

disposal system.

Borehole plugging practices near the

WIPP site also employ multiple levels of

protection that mitigate the potential

impact of oil and gas operations in the

immediate area. The State of New

Mexico regulates borehole plugging

practices with a robust series of

requirements that control the flow of

fluid in the subsurface (New Mexico Oil

Conservation Division, Order R–III–P).

The use of these measures reduce the

chance of any fluid flow toward or into

the repository using current methods

and technology.

Fluid injection for brine disposal,

waterflood, or pressure maintenance

could affect the disposal system if the

injected brine were to reach the waste

area by way of migration through Salado

anhydrites (calcium sulfate rock)

(markerbeds 138 or 139). DOE analyzed

this scenario in two different modeling

studies (Docket A–93–02, Item II–G–1,

Reference #611, and Item II–I–36) as

well as in a study that identified well

construction and operating practices in

the vicinity of WIPP. The results of the

modeling studies showed that little or

no brine would be expected to reach the

WIPP waste area through the anhydrite

interbeds. The amount of brine that is

modeled to reach the repository in the

initial study (Docket A–93–02, Item II–

G–1, Reference #611) is within the

amount that is already accounted for in

PA, and does not cause the WIPP to

violate the disposal regulations.

An examination of current practice for

fluid injection techniques confirms that

the effects of fluid injection can also be

expected to be highly localized. All

injection operations in the vicinity of

the WIPP site are controlled by the

underground injection control

requirements of the EPA. (40 CFR Parts

144 and 146) The requirements limit the

flow rates of injection fluids and the

maximum pressures that can be used in

all injection wells. In addition, the

injection well operator is required to

evaluate the area of influence of any

injection well before injection

operations can be approved, and the

State of New Mexico monitors the

performance of injection operations

periodically by requiring stringent

reporting procedures.

Regarding abandonment, DOE

indicated (Appendix SCR.3.3.1.4.2 of

the CCA) that abandoned deep

boreholes that do not intersect waste

panels have been eliminated from the

PA calculations on the basis of low

consequence to the performance of the

disposal system. This is because the rate

of fluid flow through a borehole located
58836 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

more than a meter away from the waste

panels is so small that it would have an

insignificant impact on releases.

EPA’s review of DOE’s modeling

studies and analyses of well

construction and operating practices

found that the parameterization (e.g.,

injection rate and volumes) and model

representation (e.g., incorporation of

stratigraphy) used in DOE’s modeling

are consistent with those characteristics

identified independently by EPA for the

region in the southwest part of the land

withdrawal area (the location of the

section 4(b)(5)(B) leases). (Docket A–93–

02, Item III–B–27) DOE’s analysis of

drilling for the PA indicated that deep

wells drilled into the controlled area,

but away from the waste disposal rooms

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

(and in turn, on compliance with the

disposal regulations). Based on EPA’s

findings that DOE adequately modeled

human intrusion scenarios in PA, and

on the additional analyses described

above, EPA concludes that potential

activities at the section 4(b)(5)(B) leases

do not cause the WIPP to violate the

disposal regulations. 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.

XV. Administrative Requirements

A. Executive Order 12866

Under Executive Order 12866, (58 FR

51,735; 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 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 will be 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

proposed rule would 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

Unfunded Mandates Reform Act of 1995

(UMRA) (Pub. L. 104–4), 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

specifically set forth by the Congress in

the Waste Isolation Pilot Plant Land

Withdrawal Act (Pub. L. 102–579).

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 and minority communities.

EPA has complied with this mandate.

EPA involved minority and low-income

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 assist 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. 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. 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. EPA also developed a vast

mailing list, which includes many lowincome and minority groups, to

systematically provide interested parties

with copies of EPA’s public information

documents and other materials. EPA

will continue its efforts toward open

communication and outreach during the

development of the final rule.

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: October 23, 1997.

Carol M. Browner,

Administrator.

For the reasons set out in the

preamble, 40 CFR Part 194 is proposed

to be amended as follows.
Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules 58837

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: The Waste Isolation Pilot Plant

Land Withdrawal Act of 1992, Pub. L. 102–

579, 106 Stat. 4777, as amended by the 1996

LWA Amendments, Pub. L. 104–201;

Reorganization Plan No. 3 of 1970, 5 U.S.C.

app. 1; Atomic Energy Act of 1954, as

amended, and Nuclear Waste Policy Act of

1982, 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. 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 Seal 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 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 Item II–G–1) instead of fresh

water concrete.

Condition 2: § 194.22, Quality

Assurance. (a) 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.

(b) Upon submission by DOE of sitespecific quality assurance program

plans, EPA will evaluate the relevant

quality assurance program at the

relevant waste generator site by

conducting a quality assurance audit or

an inspection of a DOE quality

assurance audit. EPA will publish a

notice in the Federal Register

announcing its intent to evaluate the

relevant quality assurance program, and

soliciting public comment on the

quality assurance program plans and

appropriate audit documentation. A

public comment period of at least 30

days will be allowed.

(c) EPA’s written approval that the

requisite quality assurance requirements

have been met at a waste generator site

will be conveyed in a letter from the

Administrator’s authorized

representative to the Department. No

such approval shall be granted until

after the end of the public comment

period described in paragraph (b) of this

condition. A copy of EPA’s approval

letter will be placed in the public

dockets in accordance with § 194.67.

The results of any audits or inspections

conducted by the Agency to evaluate the

quality assurance programs described in

paragraph (a) of this condition will also

be placed in the dockets described in

§ 194.67.

(d) EPA will conduct inspections, in

accordance with §§ 194.21 and

194.22(e), to confirm the continued

compliance of the programs approved

under paragraphs (2)(b) and (c) of this

condition. The results of such

inspections will be made available to

the public through the Agency’s public

dockets, as described in § 194.67.

Condition 3: § 194.24, Waste

Characterization. (a) The Secretary may

allow shipment for disposal at the WIPP

of retrievably stored (legacy) debris

waste streams, at the Los Alamos

National Laboratory (‘‘LANL’’), that can

be characterized using the systems and

processes documented in Docket A–93–

02, Item II–I–70. The Secretary shall not

allow shipment of any waste from any

other LANL waste streams or from any

other waste generator site for disposal at

the WIPP until the Agency determines

that the site has:

(1) provided information on how

process knowledge will be used for

waste characterization of the waste

stream(s) proposed for disposal at the

WIPP,

(2) 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 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.

(b) The Agency will conduct an audit

or an inspection of a DOE 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 audit or

inspection in the Federal Register. In

that notice, the Agency will also solicit

public comment on all appropriate audit

documentation, which will be placed in

the dockets described in § 194.67. A

public comment period of at least 30

days will be allowed.

(c) EPA’s written approval of the

waste characterization programs

described in paragraph (a) of this

condition 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 approval shall be granted until

after the end of the public comment

period described in paragraph (b) of this

condition. A copy of EPA’s approval

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 (a)(1) and

(2) of this condition will also be placed

in the dockets described in § 194.67.

(d) The Administrator’s authorized

representative(s) will conduct

inspections, in accordance with

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

continued compliance of the plans

approved under paragraphs (b) and (c)

of this condition. The results of such

inspections will be made available to
58838 Federal Register / Vol. 62, No. 210 / Thursday, October 30, 1997 / Proposed Rules

the public through the Agency’s public

dockets, as described in § 194.67.

Condition 4: § 194.43, Passive

Institutional Controls. (a) Not later than

the final re-certification 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 a 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 DOE 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, EPA will place such

documentation in the public dockets

identified in § 194.67. The Agency will

determine if a modification to the

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. 97–28647 Filed 10–29–97; 8:45 am]

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