U.S. NUCLEAR REGULATORY COMMISSION PLAN FOR

MONITORING DISPOSAL ACTIONS TAKEN BY THE 

U.S. DEPARTMENT OF ENERGY AT THE IDAHO NATIONAL

LABORATORY IDAHO NUCLEAR TECHNOLOGY AND

ENGINEERING CENTER TANK FARM FACILITY

IN ACCORDANCE WITH THE NATIONAL DEFENSE

AUTHORIZATION ACT FOR FISCAL YEAR 2005

April 13, 2007
ii

CONTENTS

Section Page

FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

ACRONYMS AND ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

1 INTRODUCTION ......................................................1

1.1 Background ....................................................1

1.2 Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 Interfacing With the State of Idaho ...................................1

2 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.40—

GENERAL REQUIREMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.41—PROTECTION OF

GENERAL POPULATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1 Technical Reviews of KMAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.1.1 KMA 1—Residual Waste Sampling ............................4

3.1.2 KMA 2—Grout Formulation and Performance ....................9

3.1.3 KMA 3—Hydrological Uncertainties . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1.4 KMA 5—Engineered Surface Barrier/Infiltration Reduction . . . . . . . . . . 13

3.1.5 Performance Assessment Process Review . . . . . . . . . . . . . . . . . . . . . 16

3.1.6 Review of Environmental Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.2 Onsite Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.2.1 Residual Waste Sampling (KMA 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.2.2 Grout Formulation, Sampling, and Placement (KMA 2) . . . . . . . . . . . . 22

3.2.3 Engineered Surface Barrier Construction (KMA 5) . . . . . . . . . . . . . . . . 23

3.2.4 Environmental Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3.2.5 Site Access Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.3 Potential Long-Term Compliance Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . 26

4 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.42—PROTECTION

FROM INADVERTENT INTRUSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.1 Technical Reviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4.2 Onsite Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.43—

PROTECTION DURING OPERATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1 Technical Review of KMA 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

5.1.1 Review of Radiation Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
iii
iv

CONTENTS (continued)

Section Page

5.1.2 Review of Environmental Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.2 Onsite Observations of KMA 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.2.1 Radiation Protection Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5.2.2 Environmental Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

6 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.44—

SITE STABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.1 Technical Reviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6.2 Onsite Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

7 DOCUMENTATION OF FINDINGS AND IMPLEMENTATION PLAN REVISIONS . . . 35

7.1 Onsite Observation Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

7.2 Annual Compliance Monitoring Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

7.3 Noncompliance Letters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

APPENDIX A—FACTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

APPENDIX B—SUMMARY OF MONITORING ACTIVITIES . . . . . . . . . . . . . . . . . . . . . . . . . . 45

CONTRIBUTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
v

FIGURES

Figure Page

1 Conceptual Design Features of the Infiltration-Reducing Cap . . . . . . . . . . . . . . . . . . . 15

2 Conceptual Design Features of the Worker Protection Cap . . . . . . . . . . . . . . . . . . . . 15

3 INTEC Monitor Well and Lysimeter Locations (Taken From DOE Idaho, 2006f) . . . . . 20

4 Idaho DEQ Monitoring Locations <http://www/deq.state.id.us/> . . . . . . . . . . . . . . . . . 21

5 Topical Areas Expected in the Annual Monitoring Report . . . . . . . . . . . . . . . . . . . . . . 37

6 Potential Sources of DOE Noncompliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
vi

TABLES

Table Page

1 Assumed Single Tank Inventories for Tanks WM-187 Through WM-190 ...........7

2 Assumed Tank WM-187 Sand Pad Inventory ................................8

3 Types of Notification Letters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
vii

ACRONYMS AND ABBREVIATIONS

ALARA As Low As Is Reasonably Achievable

ASTM American Society of Testing and Materials

CERCLA Comprehensive Environmental Response, Compensation, and

Liability Act

CNWRA Center for Nuclear Waste Regulatory Analyses

DEQ Department of Environmental Quality

DOE U.S. Department of Energy

DQA Data Quality Assessment

DQO Data Quality Objective

HCM Hydrogeologic Conceptual Model

HRR Highly Radioactive Radionuclide

HWMA Hazardous Waste Management Act

Idaho DEQ Idaho Department of Environmental Quality

INL Idaho National Laboratory

INTEC Idaho Nuclear Technology and Engineering Center

KMA Key Monitoring Area

M&O Management and Operation

NDAA National Defense Authorization Act for Fiscal Year 2005

PA Performance Assessment

RAI Request for Additional Information

RCRA Resource Conservation and Recovery Act

ROD Record of Decision

RPP Radiation Protection Program

SAP Sampling and Analysis Plan

SRPA Snake River Plain Aquifer

TER Technical Evaluation Report

TFF Tank Farm Facility

USGS U.S. Geological Survey
viii

DEFINITIONS

Closed activity A monitoring activity where a key assumption made or key

parameter used by the U.S. Department of Energy (DOE) in its

assessment has been either substantiated or determined not to

be important in meeting the performance objectives of

10 CFR Part 61, Subpart C.

Disposal The isolation of radioactive wastes from the biosphere.

Highly radioactive

radionuclides

Those radionuclides that contribute most significantly to risk to

the public, workers, and the environment.

Key monitoring area Areas that the U.S. Nuclear Regulatory Commission (NRC) has

determined to be important, through the review of DOE waste

determination that describes its waste disposal actions, to

demonstrating that performance objectives listed in

10 CFR Part 61, Subpart C, will be met.

Monitoring activities NRC and state activities to monitor DOE disposal actions to

assess compliance with the performance objectives listed in 

10 CFR Part 61, Subpart C. 

Noncompliance A conclusion that DOE’s disposal actions will not be in

compliance with the performance objectives of 10 CFR Part 61,

Subpart C, or that there is an insufficient basis to assess

whether DOE’s waste disposal action will result in compliance

with the performance objectives.

Onsite Areas of the DOE site where monitoring activities will be carried

out. This may include areas of the site outside of the Tank

Farm Facility. 

Open activity Monitoring activity that has not been closed and for which

sufficient information has not been obtained to fully assess

compliance with a 10 CFR Part 61, Subpart C, performance

objective.

Open-noncompliant

activity

An ongoing monitoring activity that has provided evidence that

the performance objectives of 10 CFR Part 61, Subpart C, are

currently not being met or will not be met in the future or for

which insufficient competent technical bases have been

provided to determine that the performance objectives will be

met.
ix

DEFINITIONS (continued)

Operations The time frame during which DOE carries out its waste disposal

actions, through the end of the institutional control period. For

the purpose of this plan, DOE actions involving waste disposal

are considered to include performance assessment

development (analytical modeling), waste removal, grouting,

stabilization, observation, maintenance, or other similar

activities. 

Performance assessment A type of systematic (risk) analysis that addresses (a) what can

happen, (b) how likely it is to happen, (c) what the resulting

impacts are, and (d) how these impacts compare to specifically

defined standards.

Performance objectives NRC 10 CFR Part 61, Subpart C, requirements for low-level

waste disposal facilities that include protection of the general

population from releases of radioactivity (10 CFR 61.41),

protection of individuals from inadvertent intrusion 

(10 CFR 61.42), protection of individuals during operations 

(10 CFR 61.43), and stability of the disposal site after

closure (10 CFR 61.44).

Waste determination (or

non-high-level waste

determination)

DOE documentation required by Section 3116 of the Ronald

Reagan National Defense Authorization Act of Fiscal Year

2005, that to demonstrates a specific waste stream is not highlevel waste.

Worker DOE personnel or contractors who carry out operational

activities at the disposal facility. For the purpose of this plan,

10 CFR Part 835 dose limits (comparable to 10 CFR Part 20)

would apply for radiation workers.
x

EXECUTIVE SUMMARY

The Ronald Reagan National Defense Authorization Act for Fiscal Year 2005 (NDAA)

authorizes the U.S. Department of Energy (DOE) in consultation with the 

U.S. Nuclear Regulatory Commission (NRC) to determine whether certain radioactive waste

related to reprocessing of spent nuclear fuel is not high-level waste, provided certain criteria are

met. The NDAA only applies to DOE facilities in South Carolina and Idaho. The NDAA also

requires NRC to coordinate with the covered state (i.e., South Carolina or Idaho) to monitor

DOE disposal actions to assess compliance with 10 CFR Part 61, Subpart C, performance

objectives for low-level waste. These performance objectives include (i) protection of the

general population from releases of radioactivity (10 CFR 61.41), (ii) protection of individuals

against inadvertent intrusion (10 CFR 61.42), (iii) protection of individuals during operations

(10 CFR 61.43), and (iv) stability of the disposal site after closure (10 CFR 61.44). This

monitoring plan details NRC plans to assess compliance with each of these performance

objectives for residual waste remaining in the high-level waste tanks at the Idaho National

Laboratory (INL) near Idaho Falls, Idaho. NRC began interacting with the State of Idaho (see

Section 1.3) while performing its consultative role with DOE under the NDAA. 

On September 7, 2005, DOE submitted a draft waste determination for residual waste

incidental to reprocessing, including sodium-bearing waste, in the Idaho Nuclear Technology

and Engineering Center Tank Farm Facility (INTEC TFF) at INL. DOE prepared a draft waste

determination and supporting performance assessment (PA) to demonstrate compliance with

NDAA criteria including demonstration of compliance with the performance objectives listed

above. In its consultative role, the NRC staff reviewed the draft waste determination and PA

and concluded with reasonable assurance that NDAA criteria could be met for residual waste

stored in the INTEC TFF. NRC documented the results of its review in a technical

evaluation report (TER) issued in October 2006. DOE issued a final waste determination

in November 2006 taking into consideration the assumptions, conclusions, and

recommendations documented in NRC’s TER. 

NRC identified key attributes of the disposal facility, or key monitoring areas (KMAs), in its TER

that are important to mitigating releases of radioactivity to the environment or that are otherwise

important to DOE’s demonstration of compliance with 10 CFR Part 61, Subpart C, performance

objectives listed above. These KMAs are reproduced in Appendix A of this monitoring plan and

are discussed in detail in the sections that follow. NRC plans to perform three types of activities

to fulfill its NDAA monitoring responsibilities, focusing on these KMAs: (i) technical reviews,

(ii) onsite observations, and (iii) data reviews. Technical reviews generally focus on obtaining

additional model support for assumptions DOE makes in its PA that are considered important to

DOE’s compliance demonstration. For each of the technical review areas, onsite observations

will be generally performed to either (i) ensure data collected for detailed technical review are of

sufficient quality (e.g., observation of waste sampling used to generate data on residual waste

inventories evaluated under KMA 1, “Residual Waste Sampling”) or (ii) to observe key disposal

(or closure) activities related to technical review areas (e.g., slag and other material storage,

grout formulation and preparation, and grout placements related to KMA 2, “Grout Formulation

and Performance”). Data reviews will supplement technical reviews focusing on real-time

monitoring data that may also indicate future system performance (e.g., sampling and analysis

of perched water underneath grouted vaults for changes in chemical conditions) or review of

records or reports that can be used to directly assess compliance with performance objectives
xi

(e.g., review of radiation records). 

DOE typically uses a PA to demonstrate compliance with requirements provided in

10 CFR 61.41 and 61.42, recognizing that long-term modeling predictions are needed to

establish compliance with performance objectives today. NRC considers sufficient PA model

support coupled with observation of disposal actions that are carried out in conformance with

detailed closure plans necessary for NRC to assess that these performance objectives can be

met in the future. For example, NRC developed KMA 1, “Residual Waste Sampling,” to ensure

that the final postcleaning inventory that is developed for each cleaned tank is consistent with

assumptions made in DOE’s waste determination and PA model regarding the final waste

inventory at closure (see Sections 3.1.1, 3.2.1, 4.1, and 4.2). The final inventory of cleaned

tanks is important to DOE’s demonstration of compliance with 10 CFR 61.41 and 61.42. NRC

will also perform technical reviews and observations related to KMA 2, “Grout Formulation and

Performance” (see Sections 3.1.2 and 3.2.2) to ensure that reducing conditions will be

maintained in the grouted tank and that the short-term performance of the grouted vaults will

mitigate the release of Tc-99 and short-lived radionuclides from the disposal facility,

respectively (important model assumptions in DOE’s demonstration of compliance with 10 CFR

61.41). Technical reviews and onsite observations of KMAs 3 and 5 related to “Hydrological

Uncertainty” and “Engineered Surface Barrier and Infiltration Reduction” (see Sections 3.1.3,

3.1.4, and 3.2.3) are also important to DOE’s 10 CFR 61.41 compliance demonstration,

providing additional model support for infiltration rates and other modeling assumptions

regarding natural attenuation processes operable in the subsurface at INTEC. If cementitious

materials do not perform as well as expected, KMAs 3 and 5 can provide an additional safety

margin. Environmental data reviews (see Sections 3.1.6 and 3.2.4) will also be important to

supporting technical reviews and onsite observations related to KMAs 2, 3, and 5 by providing

performance indicator data and support for modeling assumptions regarding both engineered

and natural system performance.

Any change to DOE’s PA affects its compliance demonstration; therefore, NRC will also

evaluate any future revisions or updates to DOE’s PA (see Section 3.1.5). Additionally, onsite

observations of access controls are important to verify DOE’s assumptions regarding the

compliance point for members of the public, including inadvertent intruders, during the

institutional control period; therefore, NRC will also ensure that controls to limit site access by

members of the public are effective (see Sections 3.2.5 and 4.2). 

Compliance with the 10 CFR 61.43 performance objective can be more easily assessed by

direct observation of DOE closure activities. NRC plans to perform a graded review of DOE’s

radiological protection program while observing DOE’s most risk-significant closure activities

(e.g., tank cleaning and grout placement activities) to assess compliance with 10 CFR 61.43. 

For example, NRC will review radiation records and environmental data or reports, possibly

interview workers during closure activities, or observe environmental data collection to assess

compliance with 10 CFR 61.43, “Protection of Individuals During Operations,” addressed under

KMA 4 (see Sections 5.1 and 5.2). Finally, monitoring activities to assess compliance with

10 CFR 61.44, “Stability of the Disposal Site After Closure,” (see Sections 6.1 and 6.2) partially

overlap the technical review and onsite observation performed for KMA 2 discussed above. 

Observations of disposal facility maintenance may also be conducted to gain insights regarding

the potential long-term performance of engineered barriers. 

This monitoring plan also provides information regarding the types of monitoring reports NRC
xii

plans to prepare to document its monitoring activities (see Section 7). For example, NRC plans

to issue a report following each onsite observation and will summarize monitoring activities and

changes to the status of its monitoring activities in periodic reports. If NRC is unable to

conclude that performance objectives are currently being met or will be met in the future, NRC

will notify DOE, the covered State, and Congress. The types of notification letters related to a

finding of noncompliance are listed in Section 7.3. Appendix B summarizes NRC planned

monitoring activities by the performance objectives and monitoring plan chapter.
1

 For the first two non-high-level waste determinations under the NDAA, DOE provided NRC staff a draft waste

determination for NRC technical review as part of the consultation process. Following completion of NRC staff’s

technical evaluation, DOE finalized the waste determinations, taking into consideration the NRC’s analyses and

technical comments documented in the TERs.

1

1 INTRODUCTION

1.1 Background

To initiate consultation activities under the National Defense Authorization Act for Fiscal

Year 2005 (NDAA) for the Idaho Nuclear and Engineering Center (INTEC) tank farm facility

(TFF) at the Idaho National Laboratory (INL), U.S. Department of Energy (DOE) submitted its

draft waste determination to the U.S. Nuclear Regulatory Commission (NRC) (DOE Idaho,

2005), on September 7, 2005. This waste determination addressed waste incidental to

reprocessing, including sodium-bearing waste, stored in the INTEC TFF. NRC concluded that

there is reasonable assurance that the applicable criteria of the NDAA could be met for the

INTEC TFF in its technical evaluation report (TER) issued in October 2006 (NRC, 2006b). In

the TER, NRC staff identified several key monitoring areas (KMAs) that would assess whether

DOE is in compliance with performance objectives listed in 10 CFR Part 61, Subpart C. These

KMAs are listed and described in Section 4.4 of NRC staff’s TER (see Appendix A). 

On November 19, 2006, DOE issued its final waste determination1

 for waste incidental to

reprocessing, including sodium-bearing waste, stored in the INTEC TFF at INL in Idaho Falls,

Idaho. The disposal plans described in the final waste determination were generally consistent

with plans described in the draft waste determination. The specific technical guidance in this

monitoring plan is based on the analyses of DOE’s draft waste determination as documented in

NRC’s TER. Consequently, changes that DOE may have made to the disposal plan since the

September 7, 2005, submittal of the draft waste determination are not necessarily reflected in

this document. NRC staff expects to update this monitoring plan as necessary to reflect

changes in DOE’s disposal plans. 

1.2 Objective

The NDAA requires NRC to coordinate with the covered state (i.e., South Carolina or Idaho) to

monitor DOE disposal actions to assess compliance with 10 CFR Part 61, Subpart C,

performance objectives for low-level waste. These performance objectives include (i) protection

of the general population from releases of radioactivity (10 CFR 61.41), (ii) protection of

individuals against inadvertent intrusion (10 CFR 61.42), (iii) protection of individuals during

operations (10 CFR 61.43), and (iv) stability of the disposal site after closure (10 CFR 61.44).

This document describes the NDAA-required activities that NRC will use to monitor DOE

actions related to in-situ disposal of residual waste stored at the INTEC TFF at INL. The focus

of the monitoring is specifically tailored for each waste determination. This document includes

NRC plans for monitoring the INTEC TFF at INL; additional monitoring information can be found

in NRC’s guidance document for waste incidental to reprocessing consultation activities. 

1.3 Interfacing With the State of Idaho

Regarding DOE’s INTEC TFF waste determination, the staff began interacting with State of
2

Idaho during the consultation phase with DOE. Through discussions with staff at Idaho

Department of Environmental Quality (Idaho DEQ), it was established that State of Idaho has

two primary regulatory responsibilities related to the INTEC TFF: (i) Resource Conservation

and Recovery Act (RCRA) closure under the Hazardous Waste Management Act (HWMA) and

(ii) Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)

regulatory activities associated with historical releases from ancillary equipment associated with

the TFF that resulted in soil and groundwater contamination. 

Additionally, Idaho DEQ participates in a wide variety of nonregulatory sampling activities at the

INL site. A division of Idaho DEQ, INL Oversight, performs various activities including

environmental surveillance, impact assessment, emergency planning and response, and risk

communication. INL Oversight maintains an independent environmental surveillance program

(e.g., air, surface water, groundwater, soil, and milk sampling from onsite and offsite). The

environmental surveillance program verifies and supplements DOE Idaho monitoring programs. 

The environmental surveillance data collected by INL Oversight can be accessed through the

Idaho DEQ website. INL Oversight uses specifically designed data collection to assess

background radiation levels, to determine the impact of radioactivity releases from facilities on

the environment, and to provide valuable information regarding contaminant transport in the

environment and potential pathways of exposure to human and ecological receptors. 

INL Oversight also maintains real-time radiological and meteorological information to assist

responders in the event of an emergency. Additionally, INL Oversight publishes technical

reports and a newsletter to let the public know how INL affects the environment. 

To the extent that Idaho DEQ continues to collect environmental and radiological data at the

site, the NRC will seek to leverage the state’s review and not duplicate the efforts by performing

a similar review. For example, the NRC may be able to rely upon Idaho DEQ review of

environmental data for assessing whether or not there have been releases to the environment

or exposures to offsite members of the public. However, the NRC may still need to review

some environmental data for other purposes (e.g., to address issues related to KMA 3). Idaho

DEQ’s review of this data should allow the NRC to reduce the scope and level of its review.
3

2 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.40—

GENERAL REQUIREMENT

Section 3116 (a)(3)(A) and (B) of the NDAA states that for radioactive waste from reprocessing

of spent nuclear fuel to be determined to be non-high-level waste, it must be shown that it will

be disposed of in compliance with the performance objectives in Subpart C of Part 61 of Title

10, Code of Federal Regulations. Subpart C of 10 CFR Part 61 requires that disposal facilities

must be sited, designed, operated, closed, and controlled after closure to ensure compliance

with the performance objectives in 10 CFR 61.41 through 61.44, according to requirements in

10 CFR 61.40. To assess compliance with the requirements of §61.40 for INTEC TFF waste

disposal, NRC will rely upon its assessment of DOE’s compliance with 10 CFR 61.41 through

61.44. Specifically, the U.S. Department of Energy (DOE) will be viewed as being in

compliance with 10 CFR 61.40 as long as it is viewed as being in compliance with the other

performance objectives.
4

3 MONITORING TO ASSESS COMPLIANCE WITH

10 CFR 61.41—PROTECTION OF GENERAL POPULATION

10 CFR 61.41—Protection of the general population from releases of radioactivity. 

“Concentrations of radioactive material that may be released to the general environment in

groundwater, surface water, air, soil, plants, or animals must not result in an annual dose

exceeding an equivalent of 25 millirems to the whole body, 75 millirems to the thyroid, and

25 millirems to any other organ of any member of the public. Reasonable effort should be

made to maintain releases of radioactivity in effluents to the general environment as low as is

reasonably achievable.”

To assess compliance with 10 CFR 61.41, the U.S. Nuclear Regulatory Commission (NRC) will

review the U.S. Department of Energy’s (DOE’s) (i) performance assessment that

demonstrates the performance objective will be met, (ii) environmental data that can provide an

early indication of the facility performance, and (iii) the as low as is reasonably achievable

(ALARA) provision in 10 CFR 61.41. NRC plans to carry out three primary activities to assess

compliance with 10 CFR 61.41: technical reviews (Section 3.1), onsite observations (Section

3.2), and long-term monitoring (Section 3.3).

Section 4.4 of the technical evaluation report (TER) summarizes the key monitoring area (KMA)

staff determined to be important in assessing DOE compliance with 10 CFR Part 61, Subpart C. 

Of the five KMA identified, all but one (KMA 4, which deals with assessing compliance with 10

CFR 61.43) relate to assessing compliance with 10 CFR 61.41.

3.1 Technical Reviews of KMAs

3.1.1 KMA 1—Residual Waste Sampling

“DOE should sample tanks WM-187 through WM-190 after cleaning as stated in Section 2.3 of

the Draft Section 3116 Determination Idaho Nuclear Technology and Engineering Center Tank

Farm Facility (DOE Idaho, 2005). Sampling data and analysis of tanks WM-187 through

WM-190 after cleaning should be reviewed to ensure that the inventory for these tanks was not

significantly underestimated (i.e., similar or better waste retrieval will be achieved)

(NRC, 2006b).”

The assumed inventory for the uncleaned tanks is an important parameter that affects

demonstration of compliance with NDAA criteria (e.g., removal to the maximum extent

practical), including the performance objectives in 10 CFR Part 61, Subpart C, germane to

NRC’s monitoring responsibilities. DOE Idaho cleaned and sampled tanks WM-180 through

WM-186 from 2002 to 2005. The inventory of the remaining uncleaned tanks (WM-187 through

WM-190) was estimated using sampling data from one cleaned tank and an assumption

regarding the cleaning efficiency for uncleaned tanks. Although the NRC TER concluded

(NRC, 2006b) that DOE Idaho used reasonable approaches in developing the TFF inventory,

NRC staff recognized the importance of obtaining additional sampling data after the remaining

tanks are cleaned to support the assumptions made in DOE Idaho’s analysis. 

One of the most significant issues NRC identified with respect to DOE’s approach to developing

a final inventory was related to the number and quality of solid sample results obtained from the
5

cleaned tanks. Note that most of the radionuclide inventory for the Tank Farm Facility (TFF) is

associated with the solid residual waste, and only a small amount of activity is associated with

the liquid residual waste. DOE Idaho was not able to meet its data quality objectives (DQOs)

for solids analysis for any of the samples taken from cleaned tanks. Nonetheless, DOE Idaho

analyzed and presented results for a composite sample for one cleaned tank, WM-183, which

was used as the basis for almost the entire TFF inventory. 

Future sampling and analysis plans (SAPs) and data quality assessments (DQAs) prepared for

tanks WM-187 through WM-190 should be evaluated as part of NRC monitoring activities. For

each cleaned tank, a SAP was developed that used the DQO process to determine the

sampling strategy, location and number of samples, laboratory methods, data management,

and quality assurance controls to be used to collect, analyze, and evaluate data to support the

decisionmaking process for TFF closure. The sampling data is used to determine whether

(i) the waste is characteristic hazardous waste due to toxicity or corrosivity, (ii) Hazardous

Waste Management Act (HWMA)/Resource Conservation and Recovery Act (RCRA) action

levels for closure can be met, and (iii) DOE performance objectives for low-level waste disposal

(consistent with 10 CFR Part 61, Subpart C) can be met. The DQO process helps ensure that

the type, quantity, and quality of data used in decisionmaking are appropriate for the intended

data application. Due to the anticipated effectiveness of cleaning activities and difficulty in

obtaining a solid sample from the cleaned tanks, NRC staff recommended that DOE Idaho use

lessons learned from previous sampling campaigns to identify a sampling strategy with the

highest probability of success of obtaining representative samples of the waste for the

uncleaned tanks (e.g., use of a small submersible pump moved across the bottom of the tank

to collect residual heel samples to capture a representative collection of residual materials from

a larger portion of the tank). NRC staff should evaluate the sampling approach DOE used to

ensure that it is reasonably robust and will, to the extent practical, obtain quality data for the

uncleaned tanks despite the sampling difficulties inherent in characterizing the small quantity

of waste residuals remaining following waste retrieval activities. Specifically, NRC staff

should confirm that DOE develops and follows an SAP that addresses appropriately

defined DQOs related to sampling to assess compliance with 10 CFR Part 61, Subpart C,

performance objectives. 

A series of DQA reports provides a scientific and statistical evaluation of the quality of the

cleaned tank data to determine whether the DQOs established for sampling can be met (DOE

Idaho, 2005). NRC staff was concerned about the variability in concentrations of highly

radioactive radionuclides (HRRs) from tank to tank that could potentially affect the conclusions

in the waste determination. Based on information that DOE Idaho presented to support their

inventory estimates in response to a request for additional information (DOE Idaho, 2006a),

NRC staff analyzed solids data from a number of additional pre- and postcleaning sampling

events. After reviewing this limited information, NRC staff concluded that there is significant

variability (an order of magnitude or higher) in the solid concentrations from tank to tank

(e.g., Sr-90 and Cs-137). There is also significant variability in concentration from pre- and

postcleaning sampling for certain radionuclides (e.g., Sr-90 concentrations vary over an order

of magnitude). Uncleaned tank WM-188 appears to have a significantly higher concentration of

the relatively insoluble constituent Cs-137 than is present in cleaned tanks. The Cs-137

variability is especially important for the intruder analysis performed to demonstrate compliance

with 10 CFR 61.42 (see Section 5), because Cs-137 is the single most important radionuclide

contributing to dose for the intruder analyses. Additionally, tank WM-187 is the holding tank for

waste removed from tanks WM-180 through WM-186; therefore, additional challenges with
6

cleaning tank WM-187 may arise due to solid residual accumulation from multiple cleaned

tanks. NRC staff included this KMA to address these uncertainties with the inventory for the

uncleaned tanks. NRC staff should evaluate the postcleaning sampling inventories for tanks

WM-187 through WM-190 to be presented in DOE Idaho-developed DQAs. These DQAs

should ensure that HRR concentration variability is appropriately addressed in DOE Idaho’s

waste determination (DOE Idaho, 2005) for tanks WM-187 through WM-190.

The HRRs for groundwater that are particularly pertinent to NRC staff’s assessment of

compliance with 10 CFR 61.41 are Sr-90, Tc-99, I-129, and C-14. NRC staff’s independent

analysis using site-specific sorption coefficients also identified U-234, Am-241, and Np-237 as

potential HRRs for groundwater, however, NRC staff managed this uncertainty through review

of monitoring well data from historical contamination from the TFF. This data currently shows

low or nondetectable levels of these constituents in perched groundwater and saturated

groundwater below the site, possibly due to significant attenuation in the subsurface. Because

in-growth of Np-237 may increase the concentration and potential risk of Np-237 over time, it is

important to assess any early indication of greater than expected mobility of this constituent in

the subsurface at INL, as discussed in Section 3.1.6. Any potential HRRs for groundwater DOE

Idaho does not identify in its screening analysis will be addressed through review of monitoring

data described in Sections 3.1.3, 3.1.6, and 3.2.4. 

Tables 1 and 2 provide the assumed inventory for HRRs for the groundwater pathway, as well

as other HRRs identified for intruder and worker risk for the bounding tank (tank WM-182) and

bounding, single sand pad. To close this KMA, NRC staff must conclude that the inventory

DOE used in its performance assessment reasonably represents the inventory remaining in the

tanks after cleaning. To complete this assessment, NRC staff must evaluate DOE Idaho’s

sampling methodology, results, and analysis to estimate the postcleaning inventory for tanks

WM-187 through WM-190, expected to be completed before the scheduled year of closure,

2012. This would also entail review of DOE Idaho’s calculation of the remaining solid residual

volume in the tanks left to be cleaned [e.g., solid residual depth estimates and kriging analysis

– see Sections 3.1.1 and 3.2.2 of the INL TER (NRC, 2006b)] and the assumed density of the

solid residual heel. NRC staff should be particularly cognizant of interference issues that have

historically plagued Tc-99 and I-129 analysis, making it necessary for DOE Idaho to use

modeling to determine the inventories for these two radionuclides in the past [e.g., ORIGEN2

modeling was used to develop the inventories in DOE’s performance assessment (DOE Idaho,

2003)]. DOE Idaho addressed analytical issues associated with these two radionuclides in

updating the inventory estimates for tanks WM-180 through WM-186 to support the

postcleaning inventory presented in its waste determination (DOE Idaho, 2005). DOE Idaho

should continue to sample all HRRs to support the postcleaning inventory estimates for tanks

WM-187 through WM-190. 

NRC staff should evaluate sampling data associated with the tank WM-187 vault to determine

whether the sand pad inventory developed to address first-cycle extraction fluid contamination

of the tank WM-187 vault from a 1962 back-siphoning event is bounding. DOE Idaho used

indirect analysis from the vault samples in cleaned tank WM-185, which was also contaminated

in 1962 from a back-siphoning event, to demonstrate that the sand pad inventory it developed

through modeling is bounding. The sand pad inventory for Sr-90 is particularly relevant for

assessing compliance with 10 CFR 61.41, as short-lived radionuclides have the greatest

potential to drive the risk from TFF waste residuals (e.g., Sr-90 release and transport have the

Table 1. Assumed Single Tank Inventories for Tanks WM-187

Through WM-190
7

Radionuclide

Total Residuals (Ci)

From DOE Waste

Determination*†

Am-241 4.2 × 10!01‡

Ba-137m§ 1.14 × 10+03

Cm-242 1.32 × 10!03

Cs-137 1.14 × 10+03

C14 4.96 × 10!06

Co-602 6.3 × 10!02

I-129 7.74 × 10!04

H-3 7.17 × 10!01

Nb-94 2.06 × 10!01

Ni-59 2.51 × 10!02

Ni-63 2.86

Np-237 4.70 × 10!02

Pu-238 1.14 × 10+01

Pu-239 3.4

Pu-240 1.35

Pu-241 1.95 × 10+01

Pu-242 9.88 × 10!04

Sr-90 2.34 × 10+01

Tc-99 7.64 × 10!01

Y-90 2.34 × 10+01

Total Ci all radionuclides 2.4 × 10+03

*1Ci = 3.7C104 MBq.

†Draft waste determination radionuclide inventories are based on (i) waste

residuals estimated using remote video inspection of cleaned tank internals to

map out depth estimates of remaining residual solids and liquids across tank

bottoms using tank internal reference points of known height, (ii) best estimate

radionuclide concentrations from past and recent samples, and (iii) radioactive

decay to 2012. Analytical results for tank WM-182 were used to calculate the

liquids inventory at closure for Am-241, C-14, Cs-137, Eu-154, H-3, I-129, 

Np-237, Pu-238, Pu-239, Pu-241, Sb-125, Sr-90, Tc-99, U-234, and Y-90. 

Analytical results for Tank WM-183 were used to calculate the solids inventory at

closure for Am-241, Ba-137m, Co-60, Cs-137, I-129, Nb-94, Pu-238, Pu-239, Sb125, Sr-90, Tc-99, U-234, and Y-90.

‡The value of 0.42 Ci was taken from Table A-7 and A-12 of DOE Idaho (2005). 

The value in Table 1 of DOE Idaho (2005) appears to be a typographical error.

§A 1:1 ratio is assumed for Cs-137 to Ba-137m as a conservative estimate of

radionuclide inventory; based on decay probability, Ba-137m is approximately 95

percent of the Cs-137 inventory.

2Co-60 was not listed in Table 1 of the draft waste determination (DOE Idaho,

2005); however, it is listed in Table 2 of 10 CFR 61.55 and is therefore an HRR by

default (using DOE Idaho’s methodology). It is also included on DOE Idaho

Table 5 of HRRs (2005).

Radionuclides shown are contributors in PA dose calculations or regulated by

concentration limits in 10 CFR 61.55. The waste determination total is based on

the entire inventory of radionuclides.
8

Table 2. Assumed Tank WM-187 

Sand Pad Inventory

Radionuclides (Ci)*†

Am-241‡ 1.89 

Ba-137m 1.65 × 103 

Cm-242 1.38 × 10-5

Cs-137‡ 1.65 × 103

C-14‡ 3.90 × 10-7 

I-129‡ 1.08 × 10-6 

H-3 3.10 × 10!22 

Nb-94 2.29 × 10!2 

Ni-63 1.69 × 10!10 

Np-237 3.72 × 10!4 

Pu238‡ 2.06

Pu-239‡ 1.57 

Pu-240‡ 3.54 × 10!1

Pu-241 2.28 

Pu-242 5.69 × 10!5 

Sr-90‡ 2.49 × 102 

Tc-99‡ 2.02 × 10!12 

Y-90 2.49 × 102 

Total Ci§ 3.85 × 103

*1Ci = 3.7 × 104 Mbq.

†Radioactive decay to 2012.

‡Radionuclides based on results from the PA (DOE Idaho,

2003).

§Radionuclides shown are contributors in DOE PA dose

calculations or regulated by concentration limits in

10 CFR 61.55. The total is based on the entire inventory of

radionuclides, not just the highly radioactive radionuclides

presented in this table.

greatest uncertainty and potential consequences compared to other HRRs DOE Idaho identified 

for the groundwater pathway). Additional conceptual model implementation and sensitivity

analysis DOE Idaho performed (DOE Idaho, 2006a) in response to an NRC request for

additional information showed that the inventory for Sr-90 and other radionuclides could be

around an order of magnitude higher. Based on calculations and analysis performed by DOE

and NRC staff, it appears that, at least for Sr-90, the inventory for the sand pad is bounding. 

NRC staff should evaluate liquid vault samples from tank WM-187 using the approach detailed
9

in Section 3.2.6 of NRC’s TER for INL (NRC, 2006b) to determine whether the inventory

developed for the sand pad presented in Table 3 is also bounding for the tank WM-187

sand pad. 

The status of this KMA will remain open until postcleaning sampling and analysis of tanks 

WM-187 through WM-190 is completed (expected prior to 2012). At that time, the status of this

KMA can be closed if (i) the postcleaning inventory estimates for tanks WM-187 through

WM-190 are less than or equal to the values provided in Table 1 and (ii) analysis of sampling

data shows the sand pad inventory for tank WM-187 is expected to be bounded by the values

provided in Table 2. If the assumed inventory is less than the actual inventory based on

postcleaning sampling and analysis, NRC staff may need to have DOE Idaho evaluate the

significance of the inventory underestimation with respect to DOE Idaho demonstration of

compliance with 10 CFR 61.41 and 61.42 performance objectives.

3.1.2 KMA 2—Grout Formulation and Performance

“The final grout formulation used to stabilize the TFF waste should be consistent with design

specifications or significant deviations should be evaluated to ensure that they will not

negatively impact the expected performance of the grout. The reducing capacity of the tank

grout is important to mitigating the release of Tc-99. Short-term performance of as-emplaced

grout should be similar to or better than that assumed in the performance assessment (PA)

release modeling or significant deviations should be evaluated to determine their significance

with respect to the conclusions in the PA and TER. The short-term performance of the grouted

vault is especially important to mitigate the release of short-lived radionuclides such as Sr-90

from the contaminated sand pads that could potentially dominate the predicted doses from the

TFF within the first few hundred years (NRC, 2006b).”

In its technical evaluation of the INTEC TFF (NRC, 2006b), NRC staff concluded that the 

10 CFR Part 61.41 performance objective could be met based on the assumed performance of

a combination of multiple barriers that mitigate the release of radioactivity into the environment,

including the performance of the grouted concrete vault and tank system. For example, NRC

staff identified the reducing capacity of the tank grout as an important barrier to mitigate the 

Tc-99 release due to the presence of ground blast furnace slag in the grout formulation. The

hydration of slag in the grout mixture releases sulfide species, predominantly S2!

, into the pore

fluid, which imposes strongly reducing conditions on the system and chemically binds several

contaminants as insoluble species. Technetium is believed to react with the sulfide to form

Tc3S10 (Lukens, et al., 2005), mitigating the potential release of Tc-99 through the groundwater

pathway. Thus, the reducing capacity of the tank grout is important to DOE Idaho’s

demonstration of compliance with 10 CFR 61.41.

The effectiveness of blast furnace slag in mitigating Tc-99 release depends on its sulfide

content. The sulfide sulfur content of commercial blast furnace slag typically varies from 0.7 to

1.1 wt%. In response to an NRC staff request for additional information [clarifying request for

additional information (RAI) 3], DOE Idaho (DOE Idaho, 2006a) provided information on the

vendor slag specification to be used in the TFF encapsulation pours and, in a followup

response to NRC clarifying RAI 3 (DOE Idaho, 2006b), indicated the vendor will be contractually

required to meet American Society of Testing and Materials (ASTM) C-989 

(ASTM International, 2006). Although ASTM C-989 sets a maximum sulfide content limit
10

of 2.5 wt%, no minimum sulfide content is specified in the standard. Thus, meeting the

requirements of ASTM C–989 does not necessarily mean sulfide will be present in the 

vendor-supplied ground blast furnace slag in sufficient concentration to ensure that reducing

conditions will be maintained. DOE Idaho (DOE Idaho, 2006b) indicated that its vendor slag

specifications will require a minimum amount of sulfide sulfur that it believes will be sufficient to

induce a reducing environment. However, DOE Idaho did not specify the minimum amount. 

DOE needs to provide the minimum sulfide content it will require in its vendor slag specification. 

Because the minimum slag content required to achieve reducing conditions is uncertain,

closure of this KMA will require information on the reducing capacity of the grout. This will

demonstrate that the minimum value selected for the specific DOE grout formulation will result

in a reducing condition sufficient to mitigate the release of technetium for the specific

formulation. A procedure for such measurements is presented in Kaplan, et al. (2005).

In addition, although blast furnace slag is stable under most conditions, deterioration of the

quality and chemical reactivity of the slag can occur if it is not stored properly or is exposed to

moisture. In a followup response to an NRC clarifying RAI 3, DOE Idaho indicated it plans to

store the grout mixture in a silo to prevent contact with moisture. NRC staff onsite observations

will be necessary to confirm that the grout components are being stored in watertight silos or

bins (see Section 3.2.2).

NRC staff’s conclusion that the 10 CFR Part 61.41 performance objective could be met is also

dependent on the assumed short-term performance of the as-emplaced grout (e.g., the grouted

vault maintains its structural integrity and ability to serve as an effective hydraulic barrier in the

near term). While NRC staff generally concluded that DOE’s concrete vault and grout

performance assumptions were pessimistic, it is not clear whether DOE explicitly considered

the effects of Big Lost River seepage on the degradation of the vaults and grout [DOE’s

PORFLOW (ACRI, 2000) model results indicated that Big Lost River seepage significantly

affects flow in the immediate vicinity of the TFF, although there is uncertainty regarding the

significance of this effect]. Additionally, it is not clear whether DOE considered the potential

impact of infiltration of highly acidic waste into the TFF vaults. The short-term performance of

the grouted vault is especially important to mitigate the release of short-lived radionuclides such

as Sr-90 from the contaminated sand pads. Some method to ascertain that the short-term

performance of the grout is similar to or better than assumed in the PA release model is

necessary. For example, a monitoring system could be put in place to detect early release of

Sr-90 from the sand pad. The monitoring system could involve measuring the Sr-90

concentration in perched groundwater samples taken from monitoring wells located underneath

or adjacent to the grouted vaults. Such a system could use sampling methodologies already

used at other DOE sites, such as the West Valley Demonstration Project (Klenk, 2005) and the

Hanford site (Washington State Department of Health, 2006). Where perched water is not

present, water samples from the hydrologically unsaturated horizon could be taken. Sampling

from the unsaturated zone would be more difficult, but techniques are available to do this [some

are discussed in Orr et al. (2006)]. In addition, new technologies currently under development,

such as the Sr-90 sensor being tested for the Advanced Monitoring Systems Initiative of DOE

(http://www.nv.doe.gov/emprograms/environment/technology/amsi/default.htm),

could eventually be deployed to monitor early release of Sr-90 or Cs-137 from the sand pad.

The status of this KMA will be considered open until DOE Idaho’s demonstration 

(i) substantiates that reducing slag will provide enough sulfur content to support reducing
11

conditions in the tank grout (expected to be addressed within 5 years of closure or the

year 2017) and (ii) substantiates that the short-term performance of the grouted tank and vault

system will mitigate the release of Sr-90 and other short-lived radionuclides.

3.1.3 KMA 3—Hydrological Uncertainties

“Relevant recent and future monitoring data and modeling activities should continue to be

evaluated to ensure that hydrological uncertainties that may significantly alter the conclusions in

the PA and TER are addressed. If significant new information is found, this information should

be evaluated against the PA and TER conclusions (NRC, 2006b).”

DOE Idaho’s PA assumptions regarding the natural system performance are important to its

demonstration of compliance. Based on the assumptions made in DOE’s performance

assessment, DOE Idaho must take credit for a combination of both engineered and natural

system barriers to meet the 10 CFR 61.41 performance objective. This KMA was developed as

a result of NRC staff’s analysis that showed a number of uncertainties associated with DOE

Idaho’s groundwater model. These uncertainties include the following:

• Hydrogeologic Conceptual Model (HCM)—NRC staff analysis of groundwater data

reflecting contamination of the subsurface from historical releases from the TFF

revealed that the HCM implemented in DOE Idaho’s groundwater model (PORFLOW

model) may not be supported. DOE’s PORFLOW model predicts 600 m [2,000 ft] of

lateral transport away from the TFF (DOE Idaho, 2003), which does not appear

consistent with monitoring data in the perched and saturated zones underneath the

INTEC TFF. The uncertainty in travel paths and distances is especially important for

short-lived radionuclides such as Sr-90 that can decay to insignificant levels during

transport through the unsaturated zone prior to entry into the saturated zone where a

receptor could be exposed.

• Infiltration Rates—Infiltration rates used in a recent Comprehensive Environmental

Response, Compensation, and Liability Act (CERCLA) risk assessment model for the

INTEC TFF (DOE Idaho, 2006c) were much higher than assumed in DOE Idaho’s PA

model (DOE Idaho, 2003). Increased infiltration rates could lead to decreased travel

times and dilution of contaminants in the Snake River Plain Aquifer (SRPA). Thus,

assumed infiltration rates significantly affect predicted doses to potential receptors,

particularly for short-lived radionuclides such as Sr-90.

• Big Lost River Seepage Rates—NRC staff evaluated Big Lost River seepage rates in

the PORFLOW model and concluded that the seepage rates may have unrealistically

diluted concentrations of radiological constituents in the unsaturated zone. 

Incorporation of constant Big Lost River seepage rates as a boundary condition in the

PORFLOW model resulted in the addition of a significant amount of water to the system. 

Overly optimistic dilution factors affect predicted concentrations and dose for all

constituents.

Based on its own calculations, NRC staff provided a defensible dilution factor for SRPA flow

that was sufficient for DOE Idaho to demonstrate compliance with performance objectives. 

NRC staff concluded that with more optimistic assumptions regarding engineered barrier
12

system performance, the Sr-90 risk could be completely eliminated (i.e., Sr-90 activity can be

reduced to insignificant levels prior to release from the grouted vaults). Thus, if short-term

performance of the grouted tank and vault system is significantly better than assumed in the

PA, then hydrological uncertainty associated with Sr-90 becomes irrelevant. If short-term

performance of the grouted tank and vault system is significantly worse than assumed in the PA

(evaluated under KMA 2), then hydrological uncertainties associated with the transport of Sr-90

in the subsurface basalt and sedimentary interbeds will need to be addressed [e.g., the

expected flow paths, direction, and attenuation (dilution and sorption) of Sr-90 in the

unsaturated zone]. Sedimentary interbed sorption provides a significant barrier to mitigate the

release of Sr-90 to the unsaturated zone. A significant amount of information (e.g., laboratory

and field-derived sorption coefficients) has been collected for Sr-90 sorption to basalts and

sedimentary interbeds. However, less information is available regarding the potential for TFF

infiltration to bypass sedimentary interbeds along preferential flow pathways through fractured

basalt. This information is important to predicting natural attenuation of Sr-90 in the subsurface

at TFF. 

Based on DOE’s performance assessment, a combination of performance from both

engineered and natural barriers is needed to meet the performance objectives for Tc-99 and

I-129. If the tank grout performance (evaluated under KMA 2) becomes an issue, natural

system performance for Tc-99 and I-129 becomes increasingly important. However, natural

attenuation of Tc-99 and I-129 in the subsurface is primarily limited to dilution and dispersion,

as these two constituents are relatively nonsorbing in the subsurface at TFF. DOE could take

additional credit for infiltration controls (see Section 3.1.4), if needed, once a final remedial

decision under the CERCLA program is made for the INTEC TFF.

Closure of KMAs 2 and 3 are intimately related for all constituents. NRC staff should continue

to stay abreast of relevant monitoring and modeling activities conducted by DOE, other

agencies [e.g., U.S. Geological Survey (USGS), Idaho Department of Environmental Quality

(Idaho DEQ), National Oceanic and Atmospheric Administration], or independent research. For

example, NRC staff should request any new and significant information related to hydrological

studies at INTEC or INL, if relevant, and continue to review monitoring data (e.g., perched

groundwater and saturated zone monitoring well data collected and reports generated as part of

the CERCLA remedial alternative for the TFF, groundwater data collected, and reports

generated by USGS and Idaho DEQ) until such time that NRC staff thinks that risk-significant

hydrologic uncertainties are adequately addressed and overall system performance is

adequately constrained.

Although not required to demonstrate compliance with performance objectives, NRC staff

recommended that DOE Idaho consider updating or revising its PA model to reflect recent

monitoring data (e.g., calibration to existing groundwater data) and modeling activities

performed for the TFF under the CERCLA program (e.g., DOE Idaho, 2006b, 2004) to ensure

HCM uncertainty is appropriately addressed. Specific recommendations included consideration

of (i) the effects of historical releases on future releases from the INTEC TFF, (ii) additional

data to support a hydrology model oriented in the principal unsaturated zone flow direction

(i.e., generally to the southeast) if a two-dimensional model is retained for modeling

contaminant flow and transport in the PA, and (iii) consideration of additional data on Big Lost

River seepage rates and underflow rates. DOE Idaho should also consider the effects of

infiltration controls and future construction of a cap over the TFF on contaminant flow and

transport. If DOE Idaho revises its PA model to address these recommendations, these issues
13

may be relevant to evaluations performed under Section 3.1.5, Performance Assessment

Process Reviews.

The status of this KMA will remain open until KMA 2 related to grout performance is closed. If

issues arise during evaluation of KMA 2 (e.g., NRC staff have concerns that the tank grout will

provide reducing conditions and that the grouted tank and vault system will provide a hydraulic

barrier in the short term), then KMA 3 will become increasingly important. KMAs 2 and 3 are

therefore expected to be closed in tandem.

3.1.4 KMA 5—Engineered Surface Barrier/Infiltration Reduction

“INTEC infiltration controls and construction and maintenance of an engineered cap over the

TFF under the CERCLA program should be monitored to ensure that PA assumptions related to

infiltration and contaminant release are bounding (NRC, 2006b).”

The infiltration rate through the grouted waste form was found to be an important parameter in

DOE Idaho’s PA model (DOE Idaho, 2003), significantly affecting DOE Idaho’s demonstration

of compliance with 10 CFR 61.41. Among other things, the assumed infiltration rate affects

mass flux into the unsaturated zone and the amount of dilution in the SRPA. Predicted

concentrations and dose from short-lived, sorbing constituents such as Sr-90 are especially

sensitive to this parameter value as increased infiltration rates lead to decreased transport

times and decay. The infiltration rate DOE Idaho used in its PA (DOE Idaho, 2003) compliance

case of 4 cm/yr [2 in/yr] was significantly less than the infiltration rate of 18 cm/yr [7 in/yr] used

in the latest Remedial Investigation/Baseline Risk Assessment (RI/BRA) that evaluated the

risks associated with historical releases from TFF piping (DOE Idaho, 2006c). The increased

infiltration rate is thought to be due to impervious areas at INTEC that focus much of the

surface runoff into gravelly areas or unlined drainage ditches (DOE Idaho, 2006c). Therefore,

future infiltration controls implemented under the CERCLA program to mitigate risks associated

with TFF soils and groundwater are important to demonstrating that 10 CFR Part 61, Subpart

C, performance objectives can be met. 

Additionally, Idaho DEQ has identified another positive effect associated with construction of an

engineered cap: it dramatically slows corrosion and degradation of the grouted tank and vault

system and associated piping to help ensure that these systems, structures, and components

remain intact for at least 100 years after closure. The PA model assumption that the vault will

not degrade until after 100 years is important to demonstrating compliance with the

10 CFR 61.41 performance objective for Sr-90 as discussed under KMA 2. Idaho DEQ reached

its conclusions regarding the benefits of an infiltration barrier on engineered barrier

performance by reviewing grouting literature (both DOE and independent research) that

describes grouting longevity and various methodologies used for stabilizing residual tank waste

(Hardesty, 2006). Note that Big Lost River seepage and underflow may also affect TFF vault

and tank degradation, providing a driving force for increased infiltration of deleterious species

into cracks that may form in these structures. However, the direct contribution Big Lost River

underflow and seepage has on flow in the vicinity of the TFF is uncertain.

DOE Idaho selected a preferred remedial alternative for contaminated soils and groundwater at

the INTEC under the CERCLA program that includes an infiltration-reducing cap and worker

protection cap (DOE Idaho, 2006d). The U.S. Environmental Protection Agency and Idaho
14

DEQ concur with DOE Idaho’s selection. The infiltration-reducing cap is less than 0.3 m [1 ft]

thick and will consist of a 10-cm [4-in] infiltration-reducing layer and a 15-cm [6-in] layer of

gravel constructed over the existing tank farm soils. The cap will have a minimum slope of one

percent and a concrete drainage collection ditch for surface water runoff. This cap requires

ongoing )
15

Figure 1. Conceptual Design Features of the Infiltration-Reducing Cap

Figure 2. Conceptual Design Features of the Worker Protection Cap

maintenance (e.g., patching to ensure its effectiveness and lift stations to remove surface water

accumulating in low areas and to transport this water to a lined evaporation pond (see Figure

1). The worker protection cap varies in thickness from 1.8 m [6 ft] at the edges to 5.5 m [18 ft]

at the crown and will protect workers from external exposures, as well as reduce water

infiltration and prevent biointrusion (see Figure 2). This type of cap requires less maintenance

than the infiltration cap because it minimizes recharge by storing moisture and returning it to the

air using plants and evaporation. 

The preferred alternative will be implemented in stages with the worker protection cap

constructed on top of the infiltration-reducing cap over the central tank farm once the interfering

infrastructure is demolished (DOE Idaho, 2006d).
16

DOE Order 435.1 requires that the environmental monitoring program for the disposal facility be

designed to include measuring and evaluating releases, migration of radionuclides, disposal

unit subsidence, and changes in disposal facility and disposal site parameters that may affect

long-term performance. Although the infiltration barrier will affect long-term performance of the

disposal facility, DOE Idaho did not take credit for a robust engineered barrier in its PA (DOE

Idaho, 2003); therefore, it is not clear whether DOE plans to monitor the infiltration barrier

installed under the CERCLA program. Nonetheless, NRC staff should remain cognizant of

activities related to construction and maintenance of the infiltration-reducing cap to ensure that

it will be properly constructed to reduce infiltration to levels equal to or below those assumed in

the PA model (DOE Idaho, 2003). Technical reviews should focus on design, construction, and

maintenance activities during the institutional control period. This will ensure the engineered

barrier can mitigate the releases of short-lived radionuclides into the environment.

The main concern is to ensure that failure of the barrier does not create a situation that

enhances infiltration into the facility beyond what would naturally occur. NRC staff should

review any projected water balance analysis associated with the infiltration control design. 

Components of the water budget would include precipitation, surface drainage and runoff,

evapotranspiration, subsurface drainage away from the vaults, cap water storage, and

infiltration. Attention should be paid to the seasonal variation in precipitation and infiltration

(e.g., increased infiltration from spring snowmelts) and evapotranspiration. Staff should be

cognizant of final construction of the surface barrier as either one closure cap covering all of the

TFF boundary or constructed in sections over the TFF during and following closure. Changes

in the gradation at the surface and within the hydrologic barrier due to erosion or nonuniform

subsidence between the areas covering the TFF should be investigated to ensure that these

processes are not negatively affecting system performance. Staff should understand how the

engineered surface barrier is designed, constructed, and performs over time.

The technical review activity shall be considered closed when sufficient support demonstrates

that PA assumptions regarding infiltration rates in the compliance case are effective during and

possibly beyond the assumed institutional control period. Drainage, runoff, and infiltration rates

of the final closure cap may be measured and monitored for a designated time period to fully

substantiate the model assumption concerning infiltration rates at the TFF. Various techniques

related to monitoring moisture content in the unsaturated zone are discussed under KMA 2. 

These techniques can be used to ensure the cap is functioning as designed.

3.1.5 Performance Assessment Process Review

DOE performance assessment is a critical element for demonstrating compliance with the

performance objectives for 10 CFR 61.41 and 42 because it considers the types of releases

that could occur, transport of radionuclides through the environment, and doses to humans. In

its PA for the INTEC TFF, DOE undertook a series of sequential analyses to predict doses that

a hypothetical residential farmer could receive. Specifically, DOE performed the following

analyses: (i) DUST-MS (Sullivan, 2001) was used to estimate the rate of release of

radionuclides; (ii) the flux of radionuclides calculated leaving the source area were then input

into the PORFLOW code, which was used to analyze their transport through the unsaturated

and saturated zones to a hypothetical well; and (iii) a DOE-developed FORTRAN program

calculated the resulting all-pathway doses. 
17

With respect to the PA model, NRC staff identified a number of issues with the release and

groundwater submodels. These concerns included the following:

• Orientation of the model—NRC staff analysis of perched water levels, structure contour

maps, and the geometry of the Big Lost River in relation to the TFF revealed that the

two-dimensional PORFLOW model should have been more appropriately oriented in a

northwest-to-southeast versus north-to-south orientation. 

• Discretization of model—NRC staff analysis of DOE Idaho’s PORFLOW model revealed

that the discretization of the hydrostratigraphy (i.e., sedimentary interbeds) may have

artificially created thicker, more continuous low permeability zones. In general,

discretization of hydrostratigraphic layers can significantly affect constituent travel

distances and times. 

• Calibration of model—It was not clear to NRC staff whether DOE Idaho’s PORFLOW

model was well calibrated to water-level or analytical measurements. In fact, monitoring

data appeared to be inconsistent with model predictions. Additionally, DOE Idaho did

not consider or address pertinent analytical data that would provide more confidence in

DOE Idaho’s model and model predictions. Future analyses should consider insights

gained through evaluation of historical releases. Additional data is also needed to

support the assumed Big Lost River seepage and underflow rates that significantly

affect contaminant flow and transport and potentially engineered barrier system

performance.

• NRC staff also recommended that DOE Idaho continue to evaluate and enhance

radionuclide release models for grouted systems, which may include assessing (i) the

applicability of the Kd approach, (ii) the appropriateness of using cementitious material

Kds for waste that may not be thoroughly mixed with the poured grout, (iii) the need for

leaching experiments on expected wasteforms in the potential range of physical and

chemical conditions, and (iv) grout pore water chemistry effects on future releases from

the TFF.

Although not required to demonstrate compliance with performance objectives, given the

nature and extent of these issues and new insights gained from other assessments at INL,

DOE may revise or update its PA model to support future waste determinations at INTEC. 

Further, DOE Order 435.1 requires that DOE’s PA be reviewed and revised when there are

changes in its waste form or containers, radionuclide inventories, facility design or operation,

or closure concepts or there is an improved understanding of facility performance. On at least

an annual basis, DOE should determine the continued adequacy of its performance

assessment considering the results of data collected and analyses from research, field studies,

and monitoring. 

Given the importance of the PA to the performance demonstration, NRC staff must evaluate the

adequacy of future revisions and updates to DOE PA. Presumably, revisions to the PA should

be developed to provide greater confidence in the results. However, even an analysis that is

intended to be conservative may be nonconservative in some areas. Previous PAs completed

by DOE for the INTEC TFF have been deterministic analyses. Accordingly, any future revisions

or updates to the PA may also be deterministic. If so, it is important for the analysis to

appropriately account for uncertainty in demonstrating that the performance objectives will be
2

A legally binding public document that identifies the remedy that will be used at a group of sites under the CERCLA

program and explains why this remedy was selected. Public comments on remedial alternatives are also addressed

in this document.

18

met. Therefore, NRC staff review of PA revisions must ensure the PA adequately

demonstrates that the performance objectives can be met. Sensitivity and uncertainty analyses

can be especially useful in determining the effects and importance of changes to the

performance assessment model(s). In reviewing updates or revisions to DOE’s PA, NRC staff

should evaluate how DOE has addressed the issues listed above. 

DOE may continue to revise its PA throughout its waste disposal activities and into facility

closure. DOE may develop a final PA to represent the updated HCM and consider the final

design of the infiltration barrier constructed as part of the final action under the CERCLA

program. Thus, activities related to reviewing DOE’s PA may continue through closure of the

INTEC TFF.

3.1.6 Review of Environmental Data

Environmental monitoring is a relatively direct method of assessing compliance with the

performance objectives in 10 CFR Part 61, Subpart C (i.e., concentrations of radionuclides in

the environment can be used to assess potential doses to receptors using an exposure model

or using concentration to dose ratios calculated from risk model results). However, analysis of

direct environmental monitoring data at INTEC is confounded by the presence of significant

radioactivity released into the environment from accidental leaks and direct injection of

radioactivity into the SRPA. Additionally, because NRC must assess compliance with today’s

performance objectives based on PA modeling predictions of natural and engineered barrier

performance over a long time frame (e.g.,10,000 years), collection of short-term, environmental

data when a receptor may be exposed thousands of years in the future is of limited use. 

Nonetheless, other types of environmental data collected by DOE, other agencies, and

independent researchers is also valuable with respect to validating long-term PA model

predictions. For example, as discussed in Sections 3.1.2 through 3.1.4, NRC staff should

review all types of environmental monitoring data (e.g., moisture content within or underneath

engineered barriers, suction lysimeter and perched groundwater analytical data, Big Lost River

seepage rates, neutron moisture logging data to estimate infiltration rates) DOE collects to both

evaluate hydrogeological conceptual model uncertainty and alert NRC of potential early failure. 

Performance indicators such as changes in alkalinity below the TFF can be used as an early

warning system of potential failure of the engineered barrier system (e.g., early warning of

preferential flow paths through the engineered barrier system). 

Because the subsurface at INTEC is contaminated, NRC staff must evaluate baseline

monitoring and trend data to identify and evaluate significant changes in geochemical data. A

significant amount of groundwater monitoring data has been collected at INTEC to characterize

the subsurface, to provide data for three-dimensional modeling implementation and calibration

to estimate risks to potential receptors, and as part of remedial alternative selection for INTEC

under the CERCLA program. For example, a record of decision2

 (ROD) for INTEC perched

water was completed in 1999. This ROD requires that perched water zones be monitored to

assess perched water drain out and downward contaminant flux to the SRPA. The “Long-Term

Monitoring Plan for OU–3–13, Group 4 Perched Water” specifies the wells to be sampled, as
19

well as the required field and laboratory parameters, to satisfy ROD requirements. More

information regarding the monitoring plan and DQOs for monitoring can be found in the latest

report entitled “Annual INTEC Water Monitoring Report for Group 4–Perched Water” (2005)

published in January 2006 (DOE Idaho, 2006d). Additionally, groundwater sampling will be

performed as part of the remedial alternative for saturated groundwater. An updated Remedial

Investigation/Baseline Risk Assessment (DOE Idaho, 2006c), Feasibility Study (DOE Idaho,

2006d), and Proposed Plan (DOE Idaho, 2006e) for remediation of INTEC soils and

groundwater under the CERCLA program were completed in 2006. An ROD is expected to be

issued in 2007. Following issuance of this ROD, DOE will develop a plan for INTEC that will list

the DQOs for monitoring. The monitoring plan will specify the locations, frequency, field, and

laboratory parameters to be sampled, as well as the quality assurance procedures to be

followed as part of the monitoring program.

NRC staff should particularly note environmental data that serve as performance indicators to

evaluate engineered barrier performance. These data reviews should be coordinated with

reviews of KMAs 2 and 3 discussed previously. NRC staff should become familiar with

groundwater conditions at the site (e.g., INL groundwater is oxidized and slightly basic). 

Geochemical changes such as increasing trends in pH or concentrations of more mobile

species such as Tc-99 (the bulk of mass of more mobile species have already been transported

away from the near-field environment at TFF) in moisture samples obtained directly underneath

the TFF may be an early indication of cementitious material degradation. Likewise, increasing

concentrations of Sr-90 in suction lysimeters or perched groundwater may also signal problems

with engineered barrier performance. As discussed in Section 3.1.1, NRC staff should also

monitor the relative mobility of key groundwater constituents identified in NRC’s independent

modeling (e.g., U-234, Am-241, and Np-237). Although these constituents have not been

detected in perched water samples to date, these constituents may be slightly less mobile than

other constituents such as Sr-90 that are pervasive in perched water today or may become a

greater risk in the future due to increased activity from in-growth over time (e.g., Np-237). 

Thus, analysis of groundwater trend data collected under the CERCLA program will be a useful

tool in evaluating key modeling assumptions and assessing compliance with the 10 CFR 61.41

performance objectives. Figure 3 shows locations of monitoring well and suction lysimeters

at INTEC.

Idaho DEQ also conducts an environmental monitoring and survelliance program on and

around the INL site (see Figure 4 for monitoring well locations). The Idaho DEQ environmental

monitoring program includes collecting air, water (surface water and groundwater), soil, and

milk samples. This data collection allows an evaluation of impacts of radioactivity releases from

INL facilities and provides information regarding potential pathways of exposure. This

monitoring data may be of less use to NRC in assessing compliance with 10 CFR 61.41 (due to

the scale of monitoring), but may be more useful in assessing compliance with 10 CFR 61.43

(see Section 5.1.2). A team led by S.M. Stoller Corporation collects monitoring data and

compiles an
20

Figure 3. INTEC Monitor Well and Lysimeter Locations (Taken From DOE Idaho, 2006f)
21

Figure 4. Idaho DEQ Monitoring Locations (http://www.deq.state.id.us/)

annual report for DOE Idaho. The last report published as of the date of this monitoring plan is

entitled “Idaho National Engineering and Environmental Laboratory Site Environmental Report

Calendar Year 2004.” DOE Idaho concluded that radioactivity from current operations could not

be distinguished from worldwide fallout and natural radioactivity in the region surrounding the

INL site. The 2005 report is expected to be published during the first quarter of 2007. 

Additionally, the Management and Operating (M&O) contractor is responsible for monitoring

effluents from operating facilities. 

Monitoring will continue for an indefinite period under the CERCLA program. The monitoring

program for INTEC is quite extensive and should meet the needs of NRC staff in monitoring

short-term performance of engineered barriers. This data has also been used (and should

continue to be used) by NRC staff to address hydrogeological uncertainty at INTEC (NRC,

2006b). NRC staff evaluating this monitoring area should remain cognizant of the future

monitoring plan that will address soil and SRPA contamination under the CERCLA program

once a final ROD is issued. Changes made to INTEC monitoring plans over time should be

evaluated to ensure that DOE’s monitoring program can adequately assess compliance with
22

10 CFR Part 61, Subpart C, performance objectives. If the scope of monitoring under the

CERCLA program does not appear adequate, then NRC staff should determine whether

hydrological uncertainty has been adequately constrained in DOE’s performance

assessment modeling or additional information is needed to provide confidence in long-term

modeling predictions.

The review of environmental data to assess compliance with 10 CFR 61.41 will be an open

issue at the onset of monitoring and will remain open indefinitely. The environmental

monitoring data should be reviewed annually, and the conclusions should be included in the

annual monitoring report (it may be necessary to review quarterly reports because annual

reports for the previous year may not be available until the year after sampling). It is anticipated

that the initial reviews of DOE’s monitoring plans, which include the DQOs for monitoring, will

require more effort on the part of NRC staff, but in subsequent years, only review of monitoring

data collected and analyzed in accordance with these plans will be necessary. 

3.2 Onsite Observations

3.2.1 Residual Waste Sampling (KMA 1)

As discussed in Section 3.1.1, the inventory of radionuclides disposed of in the INTEC TFF is

important to assessing compliance with 10 CFR 61.41. To accurately estimate the 

postcleaning inventory disposed of in tanks WM-187 through WM-190 (and the contaminated

tank WM-187 vault), DOE Idaho must obtain quality solids data from these tanks (and vaults)

subsequent to cleaning activities scheduled to be completed by 2012. This onsite observation

supports the technical review described for KMA 1 in Section 3.1.1. Thus, technical review

efforts performed for waste sampling under KMA 1 should be coordinated with onsite

observations of waste sampling that are performed to evaluate whether samples are being

collected in accordance with SAPs and the quality of data is sufficient to meet DQOs. NRC

staff should also observe DOE Idaho’s use of video equipment to estimate solids residual

depths; this is used as input data for the kriging analysis that estimates the residual volume in

the cleaned tanks.

This monitoring activity supports KMA 1 “Residual Waste Sampling;” therefore, the status of

this monitoring activity should be open after the INTEC TFF final waste determination is issued. 

This onsite monitoring area can be closed with KMA 1, after cleaning activities and subsequent

postcleaning sampling activities are completed for tanks WM-187 through WM-190. 

3.2.2 Grout Formulation, Sampling, and Placement (KMA 2)

For 10 CFR Part 61.41, “Protection of the General Population,” NRC staff should evaluate

DOE’s final grout formulation used to stabilize the TFF waste for consistency with design

specifications assumed in the final waste determination (DOE Idaho, 2006g). Significant

deviations from the design specifications should be evaluated to ensure the expected grout

performance will not be negatively affected. In addition, NRC staff should evaluate DOE’s

program for sampling, testing, and accepting grout materials to ensure the materials conform to

DOE specifications and national standards, such as ASTM C–989. The verification program

should incorporate a comprehensive record-keeping system to include, for example: (i) plant

operation records, (ii) ground granulated blast furnace slag production records, (iii) laboratory
23

test results of composite or grab samples, and (iv) certification of shipping records. The sulfur

sulfide content listed in DOE vendor slag specifications should sufficiently ensure a reducing

environment in the tank grout, as determined by laboratory measurements of the reducing

capacity of the grout formulation. 

During onsite observations, NRC staff should verify that the actual grout formulation DOE uses

to stabilize the tank waste is consistent with the formulation specified in the waste

determination. Also, NRC staff should evaluate the adequacy of the verification program

pertaining to its supply of grout components, such as blast furnace slag. NRC staff’s evaluation

should be based, to the extent practicable, on direct observation of ongoing activities and

interviews with key DOE personnel. The review should evaluate certain aspects of the

program, such as

• Representativeness of the samples collected

• Adequacy of the analytical equipment

• Calibration of the analytical equipment

• Adequacy of verification records

To minimize the degradation in the quality and chemical reactivity of the slag and Portland

cement, the material must be stored in weather-tight silos or bins to prevent contact with

moisture. During onsite observations, NRC staff should examine the silos or bins for storage of

the slag and cementitious materials. This monitoring activity supports 

KMA 2 “Grout Formulation and Performance”; therefore, the status of this monitoring activity will

remain open until KMA 2 is closed (see Section 3.1.2).

In addition to the grout formulation, curing conditions are also expected to have a significant

effect on the short- and long-term performance of the emplaced grout. Numerous studies have

shown that improper curing results in a variety of undesirable effects, such as lower strength,

high permeability, and several types of cracking. For example, early age cracking could occur

due to thermal and self-dessication stresses. Thus, staff performing onsite observations should

verify grout placement is conducted under proper temperature and humidity conditions, or that

steps are taken to ensure proper curing of the grout.

3.2.3 Engineered Surface Barrier Construction (KMA 5)

As discussed in Section 3.1.4, the proposed engineered cap that will be constructed over the

TFF will serve multiple purposes, including (i) limiting infiltration into the tanks and tank facility,

(ii) protecting workers, and (iii) slowing the degradation of the grouted tanks and tank system. 

In terms of demonstrating compliance with the requirements of 10 CFR 61.41, because the

vaults are assumed to remain intact for 100 years within the PA, the cap is expected to have

some bearing on the ability of the facility to achieve that goal.

A conceptual design for the cap is described in Section 3.1.4 (see Figure 2). However, the final

cap design may change before cap installation begins. Any changes in the cap design should

be evaluated in terms of their effect on the performance demonstration. This should be

undertaken as part of the activities under Section 3.1.4. Staff should also be cognizant of cap

design changes based upon site observations or through discussion with DOE staff. 
24

Assuming that the final cap design is consistent with the features described in Section 3.1.4,

the infiltration barrier is expected to require active maintenance to ensure its effectiveness, at

least until the final cap is constructed. For example, the cap is expected to periodically require

patching. Further, lift stations will be used to remove surface water accumulating in low areas

and will transport it to a lined evaporation pond. NRC staff, as part of onsite observation

activities, should evaluate the effectiveness of maintenance activities on the cap. This may

provide insights on long-term cap performance.

NRC staff will monitor construction and maintenance activities of the cap throughout the

institutional control period as maintenance of the cap may provide valuable information on the

long-term performance, which could be important to protecting members of the public

(i.e., 10 CFR 61.41).

3.2.4 Environmental Sampling

As discussed in Section 3.1.6, NRC staff review of environmental data collected by DOE Idaho

is important to assess compliance with performance objectives in 10 CFR Part 61, Subpart C. 

Review of environmental data provides a straightforward method of determining whether doses

to members of the public meet dose-based criteria [e.g., 0.25 mSv/yr [25 mrem/yr] total

effective dose equivalent to a member of the general population from releases of radioactivity

from the disposal facility], as well as valuable information to provide confidence in long-term

modeling predictions that are used to demonstrate compliance with performance objectives. 

The onsite observation of DOE’s environmental sampling program supports the data review

discussed in Section 3.1.6. NRC staff should be cognizant of results of onsite observations of

environmental sampling programs to ensure that samples are collected in accordance with

SAPs and that the quality of data is sufficient to meet DQOs established for sampling. NRC

staff’s evaluation of environmental sampling should be based, to the extent practical, on direct

observation of ongoing activities and interviews with key DOE personnel. The review could

include evaluation or direct observation of certain aspects of the environmental sampling

program such as

• Installation of wells, lysimeters, or piezometers

• Well development

• Well purging

• Sample collection, preservation, storage, and shipment 

• Management of investigation-derived wastes

• Quality assurance and control

Types of documentation NRC staff could review prior to the onsite observation include DOE

Idaho standard operating procedures related to instrumentation installation and sampling

(e.g., Technical Procedure 6572, “Installing Lysimeters and Sampling Soil Pore Water;”

GDE–126, “Measuring Groundwater Levels;” GDE–127, “Sampling Groundwater;” GDE–162,

“Decontaminating Sampling Equipment”) and relevant well installation and monitoring plans as

discussed in more detail next. 

New well construction may be observed to ensure that quality groundwater data are collected to

assess compliance with performance objectives. All new wells are installed in accordance with

monitoring installation plans. For example, new INTEC wells were recently installed under the
25

“INTEC 2005 Monitoring Well Installation Plan.” This plan provides information regarding the

selection of well locations (e.g., based on colloidal boroscope monitoring well results that

provided flow direction information away from the contaminated zone), drilling methods (e.g., air

rotary drill), downhole geophysical logging (e.g., video, gamma, caliper, and neutron moisture

logging), management of investigation-derived wastes (e.g., management of contaminated drill

cuttings, aquifer and perched purge water, personal protective equipment, and equipment), and

document management (e.g, field log books, chain of custody forms, sample packaging for

shipment to analytical laboratories) related to well installation and associated sampling. NRC

staff should review this information prior to the onsite observation and observe well installation

activities (e.g., drilling, geophysical logging, development, and waste management) against

applicable DOE Idaho procedures and provisions discussed in the installation plans. Wells

should be constructed properly to ensure that vertical cross-contamination is avoided. 

Information obtained during downhole logging (e.g., identification of stratigraphy, fracture

zones, perched zones) provides valuable litho- and hydrostratigraphic information that can be

used to identify zones to be targeted for monitoring, as well as information that can be used to

construct complex groundwater models. Following well installation, NRC staff can compare well

construction information regarding screen depths with geologic interpretations of the subsurface

at INTEC to ensure that wells are screened in the proper or intended locations (e.g., upper

perched zones, lower perched zones, or upper SRPA). NRC staff may also want to review well

completion reports or other documentation for the existing well network to verify that older wells

were installed and are functioning properly. Field data obtained during sampling (e.g., field

notes, purge volumes, and water quality parameters) can be reviewed for all wells to ensure

that sample data obtained from these wells is of sufficient quality. 

NRC staff can also prepare for onsite observations of DOE Idaho’s environmental sampling

program by reviewing relevant monitoring plans (e.g, “Long-Term Monitoring Plan for Operable

Unit 3-13, Group 4, Perched Water”) that provide important information regarding constituents

of concern to be monitored, frequency of sampling, and types of groundwater samples to be

taken (e.g., analytical measurements or water levels from wells, piezometers, and suction

lysimeters and soil matric potential from tensiometers and pressure transducers). NRC staff

should focus on ensuring that sampling procedures, field quality assurance (e.g., field

duplicates, equipment blanks, field blanks), laboratory quality assurance (e.g., calibration,

laboratory control samples, matrix spikes), and other quality assurance and control plans are in

place and followed. Because most analytical analyses are performed at offsite laboratories

(e.g., General Engineering Laboratory in Charleston, South Carolina), NRC staff may not be

able to directly observe laboratory quality assurance and control programs, but can review

sample preparation and shipment documentation for transport to an offsite laboratory and

possibly laboratory statements of work or contracts to ensure these programs are in place. 

NRC staff should ensure that groundwater samples are appropriately obtained in accordance

with relevant site procedures and SAPs (e.g., the wells are purged and water quality

parameters are checked and are within limits).

INTEC monitoring of perched water currently occurs on a monthly basis. The frequency of

monitoring activities will be revisited in a five-year review (monitoring initiated in 2005). NRC

staff should review the monitoring plan for soils and groundwater at the INTEC TFF once it is

completed and any other relevant monitoring plans (e.g., Idaho DEQ monitoring program

discussed in Section 1.3 and pertinent M&O facility monitoring). 

Observation of the environmental sampling will be an open issue at the onset of monitoring and
26

will remain open indefinitely. NRC staff should use a graded approach in determining the level

of effort expended in performing onsite observations of DOE Idaho’s environmental sampling

program. NRC staff may be able to rely on Idaho DEQ’s oversight program to address this

monitoring area. As always, NRC staff should also coordinate any onsite observations of the

environmental sampling program with other onsite observations to reduce the number of trips

and burden on DOE to the extent practical. The results of the onsite observations should be

documented as discussed in Section 7.1.

3.2.5 Site Access Control

While performing onsite observations, NRC staff should assess the measures DOE takes to

control access to the site to understand the type of individuals that could become exposed. 

This assessment can be made through various means. One approach may be for the staff to

interview members of DOE’s security department and review cognizant records and reports. In

addition, staff may decide to tour portions of the facility to ensure that fences and other barriers

designed to prevent access to the site are intact and performing as designed. Other

approaches may be developed over time, as NRC and DOE gain experience in this arena. 

3.3 Potential Long-Term Compliance Monitoring

Probabilistic performance assessment may allow results which have a low likelihood of

occurring, but relatively high consequences. Epistemic uncertainties can include unexpected

failure modes, design and construction errors, as well as analysis errors, which are difficult to

bound in any manner. Significant, low probability events may occur and cause changes to the

overall conceptual model of the facility. A long-term environmental monitoring plan normally is

designed and implemented to detect substantial deviations from expected disposal system

performance after operations. Such a monitoring plan would be implemented after final facility

closure, but would be developed before and at closure using and incorporating the results of

data collected under the preclosure monitoring program. The environmental monitoring

activities would focus on environmental sampling and data, usually monitoring the groundwater

at various monitoring points (see Section 3.1.6). Potential long-term compliance monitoring

activities may include changes in groundwater levels, in the groundwater flow direction, and

hydrogeochemistry. If contaminants are in the saturated zone due to intentional or

unintentional preoperational releases as is the case at INL, the existing groundwater plume may

be used to monitor changes to the groundwater system. Environmental monitoring activities

may also include tracking changes in the unsaturated zone or changes in soil gases. 

Potential long-term compliance monitoring activities for the INTEC TFF could include more than

environmental monitoring activities. The infiltration barrier could be subject to long-term

monitoring activities. If the model assumptions pertaining to infiltration can only be partially

substantiated or if other barriers are not expected to perform as well as assumed in the PA,

then NRC staff may recommend longer term monitoring activities after the engineered surface

barrier is built. Depending on the technology and knowledge at the time of cap construction,

drainage, runoff, and infiltration rates of the final closure cap may be measured and monitored

for a designated time period to fully substantiate the model assumption concerning vault

infiltration. For example, at present, test-pad lysimeters are generally reliable to test minimal

infiltration rates of less than a few mm/yr for extended times.
27

4 MONITORING TO ASSESS COMPLIANCE WITH

10 CFR 61.42—PROTECTION FROM INADVERTENT INTRUSION

10 CFR 61.42—Protection of individuals from inadvertent intrusion. 

“Design, operation, and closure of the land disposal facility must ensure protection of any

individual inadvertently intruding into the disposal site and occupying the site or contacting the

waste at any time after active institutional controls over the disposal site are removed.”

4.1 Technical Reviews

No key monitoring area (KMA) important to assessing compliance with 10 CFR 61.42 was

specifically identified in the U.S. Nuclear Regulatory Commission’s (NRC’s) technical evaluation

report (TER) for the Idaho Nuclear Technology and Engineering Center (INTEC) Tank Farm

Facility (TFF) (NRC, 2006b); however, several KMAs addressed for 10 CFR 61.41 are

important to demonstrating compliance with this performance objective as well. In general,

erosional processes are an important factor to consider in assessing compliance with 10 CFR

61.42, because erosion can expose contamination and provide additional pathways of exposure

and increased dose to inadvertent intruders. However, as discussed in NRC’s TER for the TFF

(NRC, 2006b), Idaho National Laboratory is located in a depositional environment, and erosion

is not expected to be a concern at the site. Furthermore, the preferred remedial alternative

under the Comprehensive Environmental Response, Compensation, and Liability Act program

includes an engineered cap for the INTEC TFF, which is expected to provide an additional

barrier to further mitigate potential intrusion into the waste disposal facility. 

Technical review of residual waste sampling results (KMA 1) is being monitored (see

Sections 4.1.1 and 4.2.1) to assess compliance with 10 CFR 61.41. Review of residual waste

sampling results is also pertinent to assessing 10 CFR 61.42 compliance, as the residual

inventory affects the U.S. Department of Energy’s (DOE’s) ability to meet the performance

objective related to inadvertent intrusion. Thus, the status of the residual waste sampling

technical review under 10 CFR 61.41 is directly tied to the status of technical reviews discussed

in this chapter. If the status of the residual waste sampling technical review area (Section

3.1.1) and related onsite observation area (Section 3.2.1) are closed and compliant under

61.41, then the status of inadvertent intruder performance objective will be considered closed

and compliant. 

Residual waste sampling (KMA 1) is particularly relevant for assessment of compliance with 

10 CFR 61.42 as discussed in Section 3.1.1. Significantly higher concentrations of Cs-137 in

uncleaned tanks WM-187 or WM-188 could potentially lead to intruder doses above 5 mSv/yr

[500 mrem/yr], which is the dose limit NRC uses to assess compliance with 10 CFR 61.42

(NRC, 2006a). The inventory for Cs-137 is a good indicator of the expected intruder dose

because it dominates the intruder scenarios. The inventory of Cs-137 assumed for a bounding

single tank is 1140 Ci. The final inventory for tank WM-187, which contains a contaminated

sand pad, should be evaluated against this bounding single tank inventory. The largest

combined inventory from the tank and sand pad for tank WM-185 is 2,800 Ci. Because tank

WM-188 does not have a contaminated sand pad, the tank inventory for WM-188 should be

compared to the combined Cs-137 inventory of 2800 Ci to assess whether further investigation

related to intruder dose from uncleaned tanks is necessary. Other highly radioactive

radionuclides (HRRs) related to the intruder risk are Am-241, Pu-238, Pu-239, Sr-90, and
28

Np-237. If the estimated inventory for these HRRs is significantly higher based on postcleaning

sampling for tanks WM-187 through WM-190, then the reviewer should investigate the impact

of the increased inventories on the predicted intruder dose.

Because it provided the computational basis for showing compliance, DOE’s intruder analysis is

a critical component of its demonstration of compliance with the protection of inadvertent

intruder performance objective (i.e., 10 CFR 61.42). In its waste determination for INTEC TFF,

DOE evaluated both acute and chronic radiological impacts for an intruder-well drilling and

intruder-construction scenario. As discussed in NRC TER (NRC, 2006b), DOE appropriately

demonstrated that the requirements for protection against inadvertent intrusion will be achieved. 

As noted in the TER (NRC, 2006b), results from the intruder analysis were sensitive to

assumptions regarding inventory and the assumed distribution of this inventory over the

exposure area. 

Future revisions or updates to the intruder analysis may be warranted if DOE changes its

inventory estimates or closure plans. NRC staff will need to be cognizant of any increases in

the projected inventory and consider the impacts of these increases on DOE’s performance

demonstration. A projected increase in the inventory could occur if DOE is not able to retrieve

as much waste from the remaining uncleaned tanks (i.e., tanks WM-187 through WM-190) as

planned. The projected inventory could also increase if a new, future method is found for

characterizing the inventory in the tank WM-187 sand pad and the inventory is found to be

higher than assumed in DOE’s performance assessment.

4.2 Onsite Observations

Onsite observations related to residual waste sampling (Section 3.2.1) and site access controls

(Section 3.2.5) are pertinent to onsite observations that should be performed for assessment of

compliance with 10 CFR 61.42. Site access controls are especially pertinent to assessing

compliance with 10 CFR 61.42, as DOE relies on institutional controls to prevent inadvertent

intrusion into the waste disposal facility for 100 years postclosure in its performance

assessment (estimated to be the year 2112). The maximum dose for the intruder scenarios

occurs immediately after failure of institutional controls, because relatively short-lived Cs-137

drives the intruder dose and is at its peak activity at this time. If the status of onsite observation

areas mentioned above (i.e., residual waste sampling and site access controls) are closed

under 10 CFR 61.41 and all are found to be compliant, then the status of the inadvertent

intruder performance objective will be considered closed and compliant. 

As with any compliance monitoring activity, the status could change from closed to open if new

information becomes available or significant events occur that indicate that the monitoring area

should be reopened. For example, if at some time in the future visible surface changes occur

due to erosional processes, biotic intrusion, earthquakes, or other geological processes that

could expose piping or other auxiliary equipment and potentially lead to increased doses or

additional pathways of exposure, then NRC may consider reopening this technical review or

onsite observation area to understand the effect of these changes on compliance with 

10 CFR 61.42.
29

5 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.43—

PROTECTION DURING OPERATIONS

10 CFR 61.43—Protection of individuals during operations.

“Operations at the land disposal facility must be conducted in compliance with the standards for

radiation protection set out in part 20 of this chapter, except for releases of radioactivity in

effluents from the land disposal facility, which shall be governed by 61.41 of this part. 

Every reasonable effort shall be made to maintain radiation exposures as low as is

reasonably achievable.”

5.1 Technical Review of KMA 4

“Closure and post-closure operations (until the end of active institutional controls, 100 years)

will be monitored to ensure that the 10 CFR 61.43 performance objective (protection of

individuals during operations) can be met. As part of this assessment radiation records,

environmental monitoring, and exposure assessment calculations may be reviewed (NRC,

2006b).”

KMA 4 identified in the U.S. Nuclear Regulatory Commission’s (NRC’s) technical evaluation

report (TER) for the Idaho Nuclear Technology and Engineering Center (INTEC) Tank Farm

Facility (TFF) (NRC, 2006b) specifically addresses assessment of compliance with 10 CFR

61.43. 10 CFR 61.43 is directly related to protection of individuals during operations. NRC

interprets the term “operations” as those U.S. Department of Energy (DOE) activities related to

waste removal, grouting, stabilization, observation, maintenance, or other similar activities. 

NRC intends to evaluate this KMA from the time that DOE issues its final waste determination

until the end of the institutional control period. Assuming that workers will most likely be

performing duties on a controlled DOE site under DOE’s radiation protection program, the 50

mSv/yr [5000 mrem/yr] radiation worker dose limit will apply. For members of the public,

including workers performing limited activities not covered under a DOE radiation protection

program, the 1 mSv/yr [100 mrem/yr] dose limit for members of the public will apply. To

evaluate this performance objective, NRC staff will review DOE worker radiation records, the as

low as is reasonably achievable (ALARA) program, and offsite dose assessment methods and

results to assess compliance with 10 CFR 61.43.

5.1.1 Review of Radiation Data

The performance objective in 10 CFR 61.43 for protection of individuals during operations

requires that waste disposal activities be carried out such that the radiation protection standards

set forth in 10 CFR Part 20 are met and that doses are maintained ALARA. DOE’s approach to

demonstrating protection of individuals during operations is to cross-walk the relevant DOE

regulation or limit found in 10 CFR Part 835 and relevant DOE orders with 10 CFR Part 20. 

NRC has agreed that an equivalent level of protection is provided by the relevant DOE

regulations or limits to the requirements found in 10 CFR 20.1101(d), 10 CFR 20.1201(a)(i), 

10 CFR 20.1201(a)(1)(ii), 10 CFR 20.1201(a)(2)(I), 10 CFR 20.1201(a)(2)(ii), 

10 CFR 20.1201(e), 10 CFR 20.1208(a), 10 CFR 20.1301(a)(1), 10 CFR 20.1301(a)(2), and 

10 CFR 20.1301(b). In addition, NRC has agreed that DOE has applied a number of measures

to ensure that exposure of individuals are maintained ALARA. 
30

NRC staff should, on an annual basis, request information from DOE on any violations of 

10 CFR Part 835 requirements related to workers and the general public (DOE Order 5400.5)

during its waste disposal operations. NRC may also request reports such as incident reports,

annual site worker dose reports and site environmental reports for review. 

5.1.2 Review of Environmental Data

Tank and auxiliary equipment cleaning and stabilization activities can lead to releases of

radioactivity to the environment during waste disposal operations. Monitoring and maintenance

activities during postclosure can also lead to releases and potential exposure of members of the

public involved in or observing these activities. During closure operations and until the end of

the institutional control period (assumed by DOE to be 100 years postclosure), the primary

pathway of exposure is expected to be through the air. Because institutional controls will be in

place to prevent access to the site and INTEC is located 10 miles from the closest INL site

boundary and even further away from the site boundary in the prominent wind direction (from

the southwest), releases of radioactivity from the INTEC TFF due to cleaning and stabilization

activities are expected to be indistinguishable from other Idaho National Laboratory (INL)

sources and background radioactivity levels at the site boundary where a member of the public

could be exposed. In fact, based on the “Idaho National Engineering and Environmental

Laboratory Site Environmental Report Calendar Year 2004,” DOE Idaho concluded that

radioactivity from current operations could not be distinguished from worldwide fallout and

natural radioactivity in the region surrounding INL. Nonetheless, NRC staff must evaluate DOE

Idaho’s approach to calculating offsite doses to members of the public from disposal facility

operations as part of its responsibility to assess compliance with 10 CFR 61.43. The most

efficient means of evaluating this performance objective may be through evaluation of DOE

Idaho’s bounding analysis for all INL operations. Additionally, members of the public can obtain

escorted access to the site; therefore, review of this monitoring area should also entail

requesting information from DOE on any exceedances of the public dose limit.

As discussed in Section 3.1.6, DOE Idaho maintains an environmental monitoring program to

evaluate the impacts of INL operations on members of the public. The environmental

surveillance program includes sampling air, soil, water, vegetation, animals, and foodstuffs on

and around the INL site to confirm compliance with applicable laws and regulations. The

Management and Operation (M&O) contractor monitors airborne effluents at individual INL

facilities (including INTEC) and ambient air outside the facilities to comply with appropriate

regulations and DOE orders. Particulate filters are used to monitor gross alpha-, beta-, and

gamma-emitting radionuclides such as Am-241, Pu-238, and Pu-239/240. Charcoal cartridges

are used to monitor I-131. Tritium is monitored in atmospheric moisture and precipitation. 

Filters from a network of low-volume air monitors are collected and analyzed weekly for gross

alpha and gross beta activity. Filters are then composited quarterly by location for analysis of

gamma-emitting radionuclides using gamma spectrometry and for specific alpha- and

beta-emitting radionuclides using radiochemical techniques. In addition to the membrane filter

samples, charcoal cartridges are collected and analyzed weekly for gaseous radionuclides such

as I-131 using gamma spectrometry. Tritium in water vapor in the atmosphere is monitored

using samplers located at two onsite locations and five offsite locations (DOE Idaho, 2005). 

As discussed in Section 1.3, Idaho Department of Environmental Quality (Idaho DEQ) also

maintains an environmental surveillance program [e.g., air, water (surface and groundwater),
31

soil, and milk sampling from on and off the INL site] to help independently evaluate DOE’s

monitoring and assess environmental impacts from INL facilities. Idaho DEQ publishes

quarterly and annual reports that analyze this data. Idaho DEQ has several air and radiation

monitoring stations on the INL site. To detect gamma radiation, each station is instrumented

with an electret ionization chamber, and 11 of the stations also have high-pressure ion

chambers. To the extent that Idaho DEQ continues to independently evaluate environmental

data at the site, the NRC staff should leverage the state’s evaluation in determining whether or

not there have been releases to the environment as opposed to conducting its own review of

environmental data. If Idaho DEQ indicates that there have been releases to the environment,

then the NRC staff should evaluate the significance of the release to determine whether DOE is

meeting the performance objectives.

During the operational period, DOE Idaho must demonstrate that predicted doses to members

of the public are less than 10 CFR Part 20 dose limits of 1 mSv/yr [100 mrem/yr] at the site

boundary (or to members of the public granted access to the site) from all pathways and less

than 0.1 mSv/yr [10 mrem/yr] dose limit for air emissions at the maximum point of impact at the

INL boundary. DOE Idaho must also demonstrate that the dose in any one hour in an

unrestricted area is less than 0.02 mSv [2 mrem]. DOE must use effluent concentration data

described above and pathway analysis to demonstrate compliance with the portion of the

10 CFR 61.43 performance objective pertaining to members of the public. NRC staff should

evaluate the quality of the data collected by DOE (e.g., monitoring locations, frequency,

analytical methods, quality assurance and control), as well as the dose calculation methods

used to estimate doses to members of the public. Information regarding the dose methodology

used to calculate doses to members of the public are contained in DOE Idaho’s annual site

environmental reports (see DOE Idaho, 2005). These reports should be reviewed by NRC

technical staff on a periodic basis during the institutional control period. To the extent that the

Idaho DEQ continues to collect environmental data (e.g., air and radiation) at the site, the staff

should consider using the state’s data and analysis to confirm that the public dose limits have

not been exceeded. 

NRC staff should use a graded approach to evaluating this technical review area. Idaho DEQ’s

independent environmental sampling program may sufficiently address this technical review

area. The review of environmental data to assess compliance with 10 CFR 61.43, the

protection of individuals during operations, will be classified as an open issue at the onset of

monitoring. This monitoring area can be permanently closed following the end of the

institutional control period (100 years after closure of the INTEC TFF). NRC staff should

consider independent information to assess the quality of DOE data (e.g., Idaho DEQ

environmental monitoring data and data analysis). 

5.2 Onsite Observations of KMA 4

As discussed in Sections 3.2.5 and 4.2, NRC staff will perform onsite observations of DOE’s

program to control access to the site. The effectiveness of access controls is pertinent to

assessing compliance with the 10 CFR 61.43 performance objective with respect to determining

the exposure pathways and point of compliance for members of the public during operations. 

NRC staff also plan to perform onsite observations of DOE’s radiation protection and

environmental sampling programs as indicated next.
32

5.2.1 Radiation Protection Program 

In order to determine the validity of the various reports and records discussed in Section 5.1.1,

NRC staff should review, with the aid of key DOE personnel, the Radiation Protection Program

(RPP) responsible for producing such reports and records while performing onsite observations. 

Through discussions, interviews, and perhaps onsite tours with DOE or DOE contractor

personnel, NRC staff should assess whether the programs and policies are consistent with the

description presented in the draft waste determination (DOE Idaho, 2005). Specifically, NRC

staff should verify that personnel involved in the waste disposal operations are provided

dosimetry and are familiar with the requirements of the RPP.

5.2.2 Environmental Sampling

During the operational period, NRC staff may participate in onsite observations of DOE Idaho’s

environmental sampling program. As discussed in more detail in Section 3.2.4, NRC staff

should identify relevant DOE procedures related to environmental sampling to ensure that the

quality of data DOE is obtaining is adequate to assess public dose. NRC staff should consider

evaluating, at least once, sample locations, frequency, methodology, and collection techniques,

as well as quality assurance documentation such as chain of custody forms and sample

identification information to understand the overall quality of the program. Given the relevance

of the air pathway for evaluating doses to members of the public during operations, NRC staff

should consider reviewing data associated with DOE Idaho’s onsite meteorological program

that is used to collect data for use in air dispersion models (e.g., wind speed and differential

temperature to determine stability class). 

NRC staff should coordinate onsite observations of environmental sampling with those

conducted under Section 3.2.4 or other onsite observations to the extent practical. A graded

approach should be used to evaluate DOE Idaho’s environmental monitoring program with the

level of effort expected to be greater at the onset of monitoring and much less in subsequent

years, after NRC staff is confident that DOE Idaho’s environmental surveillance program can

adequately estimate doses to members of the public. Additionally, Idaho DEQ’s independent

environmental surveillance program can be used to evaluate the adequacy of DOE Idaho’s

monitoring program to estimate offsite doses. This onsite observation monitoring area should

be closed after the end of institutional controls.
33

6 MONITORING TO ASSESS COMPLIANCE WITH 10 CFR 61.44—

SITE STABILITY

10 CFR 61.44—Stability of the disposal site after closure.

“The disposal facility must be sited, designed, used, operated, and closed to achieve long-term

stability of the disposal site and to eliminate to the extent practicable the need for ongoing

active maintenance of the disposal site following closure so that only surveillance, monitoring,

or minor custodial care are required.”

6.1 Technical Reviews

No KMA important to assessing compliance specifically for 10 CFR 61.44 was identified in the

U.S. Nuclear Regulatory Commission (NRC) staff’s Idaho Nuclear Technology and Engineering

Center (INTEC) Tank Farm Facility (TFF) technical evaluation report (TER) (NRC, 2006b);

however, the key attribute of the disposal facility responsible for providing site stability is the

structural integrity provided by the grout mortar. The structural stability of the TFF relies on

grouting the space between the tank and the concrete vault and the space inside the tank. 

Grout will create a solid monolith with little void space and eliminate differential settlement;

significant structural collapse is not anticipated. The process piping will be filled with grout upon

facility closure to ensure structural stability, and erosion processes would not be expected to

imperil site stability. Monitoring activities to assess compliance with 10 CFR 61.44 will therefore

concentrate on the structural integrity of the grout that is being monitored within the technical

review and onsite observation areas of another performance objective. Technical reviews of

grout formulation and performance, as identified in KMA 2, and onsite grout formulation and

sampling reviews will be conducted to determine compliance with 10 CFR 61.41. Compliance

or noncompliance with the performance objective for 10 CFR 61.44 is associated with the

status of the aforementioned monitoring activities. As with any compliance monitoring activity,

the status could change from closed to open if new information becomes available or significant

events occur that indicate that the monitoring area should be reopened. For example, new

insights on the structural performance of the grout or on dramatic climate changes may indicate

that the monitoring activity status would need to be changed. In addition, if minimal

surveillance, monitoring, and custodial care are carried out after closure, NRC staff expects to

be informed of changes to features in the immediate area that might effect the stability of the

disposal site. These changes may include erosional features caused by extreme precipitation

events or long-term processes or visible surface changes due to significant biotic intrusion,

earthquakes, or other geological processes. 

6.2 Onsite Observations

U.S. Department of Energy (DOE) Idaho plans to fill the tanks and vaults with 10 m [33 ft] or

more of grout to ensure that the requirements of 10 CFR 61.44 are achieved. The grouted

facility is expected to have minimal void space, eliminating concern about differential

settlement; NRC should verify this during its observation of the grout pour. Figure 2 shows

DOE’s conceptual design of the engineered cap for the INTEC TFF. The cap is expected to

provide protection against the natural elements and thus help slow facility degradation. In its

TER (NRC, 2006b) and as noted previously, NRC staff concluded that DOE Idaho had

appropriately demonstrated that the 10 CFR 61.44 performance objective could be met.
34

As noted previously, NRC staff will rely upon monitoring activities carried out to determine

compliance with 10 CFR 61.41. NRC staff will visually observe the facility for obvious signs of

failure as part of its normal onsite activities. For example, evidence of ponded water on the cap

surface may be a sign of differential settlement. Surface fractures may be evidence of

underlying displacement. Staff may also plan site visits to observe the facility after severe

weather events (e.g., storms, tornados, etc.) to ascertain how well the facility can withstand

these events. DOE is expected to carry out an active maintenance program for the facility

through the end of the institutional control period; therefore, any obvious signs of facility

degradation should be repaired. However, such degradation can provide insights on potential

long-term facility performance. NRC staff should also discuss any maintenance activities that

are performed at the disposal facility (e.g., repairs to engineered surface barriers) with DOE

Idaho staff.

This monitoring activity is not expected to begin in earnest until the tanks are grouted and the

engineered cap is placed over the disposal facility. This monitoring activity is expected to

remain open indefinitely.
3

It is anticipated that during the early phases of carrying out its monitoring activities, NRC will develop an annual

report. However, as the monitoring program progresses and the number of monitoring activities diminish, the staff

will need to reassess whether less frequent reporting is warranted.

35

7 DOCUMENTATION OF FINDINGS AND IMPLEMENTATION

PLAN REVISIONS 

7.1 Onsite Observation Reports

The U.S. Nuclear Regulatory Commission (NRC) staff participating in onsite observations will

be required to develop a report after each site visit. This report will provide a written summary

of what was done and any findings from the visit. The report should include a list of the

participants, a description of the activities undertaken, and any staff assessment. This report

should also describe any issues that may warrant additional investigation through either the

staff’s technical review or future site visits. Activities that are deemed “closed” as a result of the

onsite observation should be so designated in the report. 

The report of the onsite monitoring results will be provided to the U.S. Department of Energy

(DOE) and State of Idaho by letter within 60 days following the site visit. 

7.2 Annual Compliance Monitoring Reports

Staff findings for the various technical and onsite reviews completed throughout the year will

be documented in an annual report.3

 It is anticipated that staff will develop a written report of

its findings immediately following any onsite visits (see Section 7.1). In addition, the annual

report will also document the staff’s technical reviews of data, its review of reports or

analyses to address the KMAs, and its review of any updates or revisions to DOE’s

performance assessment. 

In documenting its review, the staff will need to specifically describe what was reviewed,

whether there is reasonable assurance that the performance objectives can be met (this will

include a description of the specific performance objectives that apply), and the basis for the

staff findings (e.g., independent analyses conducted by the staff, supporting studies, expert

opinion, etc.). In addition, the staff should describe any recommended action (e.g., additional

studies or analyses) that should be undertaken to close out open activities.

The annual monitoring report should also serve as a vehicle for tracking whether monitoring

activities discussed in Sections 2–6 of this report are considered closed, open, or

open-noncompliant. For any activity that was previously closed but is being reopened, the

staff should describe its basis for reopening the activity and its expected plans for monitoring

the activity. The annual monitoring report should also describe any new monitoring activities

identified during the year and the basis for opening them. The staff should also identify any

open and open-noncompliant activities that are expected to be carried out for the upcoming

year. The annual compliance monitoring report should document any actions or results that

might change the status of noncompliant activities. For activities that have been closed, the

staff should document its basis for closing the review and any conditions that could

prompt reopening.
4

The frequency of these meetings is expected to change as implementation of the NRC monitoring program

progresses. As the number of monitoring activities diminish, NRC staff will reevaluate the meeting frequency.

5

This could also include determining the need for less frequent reporting and meetings.

36

It is envisioned that staff will meet with DOE and the State on an annual4

 basis to discuss the

status of the monitoring program. This meeting could help determine which activities are still

open, what actions are needed to close activities, and potential areas of concern. The staff

may also want to use this meeting to identify potential revisions that need to be made to the

monitoring program in the future.5

Lastly, the monitoring report should describe any developing issues that should be brought to

the attention of management. For example, the staff may have identified issues through either

its technical review or onsite visits that are not significant enough to prevent performance

objectives from being met, but could affect the performance demonstration over time. The

disposition of any issues raised during the previous year should also be described in the report.

Figure 5 shows the topical areas that are likely to be covered in the annual monitoring report. A

copy of the report will be provided to DOE and the State for information purposes. In addition,

the report will be made publicly available on NRC’s website.

7.3 Noncompliance Letters

In accordance with the NDAA, NRC is required to inform DOE, the covered State, and

Congress if it considers any of DOE’s waste disposal actions to be noncompliant with the

performance objectives of 10 CFR Part 61, Subpart C. The specific congressional committees

that NRC is required to inform are the Committee on Armed Services, Energy and Commerce,

and Appropriations in the House of Representatives and the Committee on Armed Services,

Energy and Natural Resources, Environment and Public Works, and Appropriations in the

Senate. NRC is required to make this notification as soon as practicable after discovery of

noncompliant conditions. In addition, the noncompliance notification letter will be made publicly

available on NRC’s website.

As the staff carries out monitoring activities outlined in this monitoring plan, it will determine

whether or not DOE is in compliance with the performance objectives. As shown in Figure 6,

there are two primary ways that DOE will be considered noncompliant: (i) if there are sufficient

indications that the criteria for one or more performance objective is currently being exceeded

or (ii) if there are sufficient indications that the criteria for one or more performance objectives

could be exceeded in the future. Possible indications that the performance objectives are

currently being exceeded would be environmental concentrations at locations where individuals

could be exposed to a dose exceeding the dose criteria. Other possible indications that the

performance objectives are currently being exceeded would be radiation doses to workers or

members of the public that exceed the dose limit or evidence of structural failure of the

disposal facility.
37

Topical Areas 

Annual Compliance Monitoring Report 

Onsite Reviews

• Areas reviewed

• Findings

• Basis for findings

• Recommended actions

Technical Reviews

• Areas reviewed

• Findings

• Basis for findings

• Recommended actions

New and Reopened Activities

• Area of concern

• Significance to performance demonstration

• Expected monitoring activities

Open-Noncompliant Activities

• Basis for status

• Actions or results that might change the status

Summary of Annual Meeting

Revisions to the Monitoring Plan

Potential Problems

Activities Closed

Figure 5. Topical Areas Expected in the Annual Monitoring Report

NRC cannot base noncompliance solely on contemporaneous noncompliance. First, given the

nature of the highly engineered facilities involved, evidence of problems meeting the

performance objectives may not be observable for hundreds of years in the future. Thus, solely

relying upon observable system failure may not allow the NRC to make a timely notification as

required by the NDAA. In addition, assessing compliance for some performance objectives

(e.g., 10 CFR 61.42) is difficult to accomplish through direct observation. Thus, the second

means by which NRC may make a finding of noncompliance is through predictive modeling that

indicates one or more of the performance objectives may not be met in the future. An indication

that DOE may exceed the performance objective(s) would be if key assumptions relied upon in

its performance demonstration cannot be substantiated as previous technical information and

evidence had indicated. “Key” in this sense means that without the assumption, the

performance demonstration cannot be made. Another indication would be if trends in the data

indicate that at some future time the performance objective criteria would be exceeded.
38

Given the different types of noncompliance, NRC anticipates using several different types of

notification letters, listed in Table 3. A Type I letter would state that there are sufficient

indications that DOE is currently not in compliance with one or more of the performance

objectives. Within the letter, NRC would describe the performance objective that may not be

met and the basis for NRC staff’s conclusion that the disposal action may not be in compliance

with the performance objective. A Type II letter would state whether there is sufficient evidence

to indicate that a performance objective will be met at some point in the future. Again, this letter

would identify the specific performance objective(s) that may not be met and the basis for NRC

staff’s conclusion that the disposal action may not be in compliance with the performance

objective. The third type of notification letter (Type III) would state whether there is an

insufficient basis to conclude that DOE will be in compliance with one or more of the

performance objectives. In this letter, NRC would identify the specific performance objectives in

which a finding cannot be made, along with the reason(s) why no finding can be made. 

Because of their significance and distribution, Type I–III letters would be sent out under the

signature of NRC Chairman. While each of the three types of notification letters are important,

Figure 6. Potential Sources of DOE Noncompliance
39

the Type I letter is the most serious because it pertains to an immediate potential threat to

public health and safety. 

Prior to sending out Type I–III letters, NRC will review its concerns in a letter (Type IV) to DOE

and the State. This will give the State an opportunity to provide input and comment and provide

DOE with an opportunity to provide information that demonstrates its compliance with the

performance objectives. Assuming that DOE provides information to support its performance

demonstration, NRC will need to review this information and decide whether it is sufficient to

conclude that the performance objectives will be met. If the staff determines that, based on the

information provided by DOE, there is sufficient basis to conclude that DOE is in compliance,

NRC will send out a notification of resolution letter (Type V). Types IV and V letters will be

made publicly available on NRC’s website. These letters formally document resolution of the

issue. If the staff determines that, based on the information DOE provides, there is still a basis

for concluding that DOE is noncompliant, NRC will send out the notification of noncompliance

letter (i.e., Type I–III).

Table 3. Types of Notification Letters

Type Notification Signature Distribution

I Indication that performance

objective(s) are currently not being

met

Chairman DOE, covered State,

and Congress

II Indication that performance

objective(s) will not be met in the

future

Chairman DOE, covered State,

and Congress

III Insufficient basis to determine that the

performance objective(s) will be met

Chairman DOE, covered State,

and Congress

IV Concerns with the performance

demonstration

Staff DOE and covered

State

V Resolution of concerns with the

performance demonstration

Staff DOE and covered

State
40

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DOE Idaho. “Response to Request for Additional Information on the Draft Section 3116

Determination Idaho Nuclear Technology and Engineering Center Tank Farm Facility.” 

ICP/EXT–06–01204. Rev. 1. Idaho Falls, Idaho: DOE Idaho. 2006a.

–––––. “DOE Responses to NRC Additional Information Request.” Idaho Falls, Idaho: DOE

Idaho. 2006b.

–––––. DOE/NE–ID–11227, “Operable Unit 3-14 Tank Farm Soil and Groundwater Remedial

Investigation/Baseline Risk Assessment.” Rev. 0. Idaho Falls, Idaho: DOE Idaho. April

2006c.

–––––. DOE/ID–11247, “Operable Unit 3-14 Tank Farm Soil and Groundwater Feasibility

Study.” Rev. 0. Idaho Falls, Idaho. DOE Idaho: May 2006d.

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(2005).” Rev. 0. Idaho Falls, Idaho. DOE Idaho: January 2006f.

–––––. DOE/ID–11226, “Basis for Section 3116 Determination for the Idaho Nuclear

Technology and Engineering Center Tank Farm Facility.” Rev. 0. Idaho Falls, Idaho. DOE

Idaho. November 2006g.

–––––. DOE/NE–ID–11226, “Draft Section 3116 Determination Idaho Nuclear Technology and

Engineering Center Tank Farm Facility–Draft.” Rev. 0. Idaho Falls, Idaho: DOE Idaho. 

September 2005.

–––––. “Evaluation of Tc-99 in Groundwater at INTEC: Summary of Phase 1 Results.” 

ICP/EXT–04-244. Rev. 0. Idaho Falls, Idaho: DOE Idaho. September 2004.

–––––. DOE/ID–10966, “Performance Assessment for the Tank Farm Facility at the Idaho

National Engineering and Environmental Laboratory.” Rev. 1. (Errata December 2, 2003). 

Idaho Falls, Idaho: DOE Idaho. 2003.
41

Hardesty, T. “Idaho National Laboratory Tank Farm Facility Ability to Meet NDAA Standards for

Classification of Tank Residuals as Low-Level Waste.” Letter (August 18) to M. Gilbertson,

Deputy Assistant Secretary, Office of Engineering & Technology, DOE. State of Idaho: DEQ. 

2006. 

Kaplan, D.I., T. Hang, and S.E. Aleman. “Estimated Duration of the Reduction Capacity Within

a High-Level Waste Tank (U).” WSRC–RP–2005–01674. Rev. 0. Aiken, South Carolina: 

Westinghouse Savannah River Company, LLC. 2005.

Klenk, D.P. “West Valley Demonstration Project Groundwater Monitoring Plan.” WVDP–239. 

Rev. 9. West Valley, New York: West Valley Nuclear Services Company. 2005.

Lukens, W.W., J.I. Bucher, D.K. Shuh, and N.M. Edelstein. “Evolution of Technetium Speciation

in Reducing Grout.” Environmental Science and Technology. Vol. 39. pp. 8,064–8,070. 2005.

Orr, D., M. Tuller, and S. Stothoff. “Review of Vadose Zone Measurement and Monitoring

Tools for Yucca Mountain Performance Confirmation Program.” San Antonio, Texas: CNWRA. 

2006.

NRC. SECY–05–0073, “Implementation of New U.S. Regulatory Commission Responsibility

under the National Defense Authorization Act of 2005 in Reviewing Waste Determinations for

the U.S. Department of Energy.” Washington, DC: U.S. Government Printing Office. 2005.

–––––. NUREG–1854, “Standard Review Plan for Activities Related to U.S. Department of

Energy Waste Determinations.” Washington, DC: NRC. May 2006a.

–––––. “U.S. Nuclear Regulatory Commission Technical Evaluation Report for the

U.S. Department of Energy Idaho National Laboratory Site Draft Section 3116 Waste

Determination for Idaho Nuclear Technology and Engineering Center Tank Farm Facility.”

Washington, DC: NRC. 2006b.

–––––. NUREG–1573. “A Performance Assessment Methodology for Low-Level Radioactive

Waste Disposal Facilities.” Washington, DC: NRC. October 2000.

Sullivan, T.M. “DUST-MS Disposal Unit Source Term–Multiple Species Data Input Guide.” 

Upton, New York: Brookhaven National Laboratory. 2001.

Washington State Department of Health. “Hanford Environmental Oversight Program 2004

Data Summary Report.” DOH 320-039. Olympia, Washington: Washington State Department

of Health, Office of Radiation Protection. 2006.
42

APPENDIX A

FACTORS
43

FACTORS

Key Monitoring

Area (KMA) Area Description

1 Residual Waste

Sampling

The U.S. Department of Energy (DOE) should

sample tanks WM-187 through WM-190 after

cleaning, as stated in Section 2.3 of the Draft

Section 3116 Determination Idaho Nuclear

Technology and Engineering Center Tank Farm

Facility (DOE Idaho, 2005). After cleaning, sampling

data and analysis of tanks WM-187 through WM190 should be reviewed to ensure that the inventory

for these tanks is not significantly underestimated

(i.e., similar or better waste retrieval will be

achieved).

2 Grout

Formulation

and

Performance

The final grout formulation used to stabilize the Tank

Farm Facility (TFF) waste should be consistent with

design specifications, or significant deviations

should be evaluated to ensure that they will not

negatively impact the expected performance of the

grout. The reducing capacity of the tank grout is

important to mitigating the release of Tc-99. Shortterm performance of as-emplaced grout should be

similar to or better than that assumed in the

performance assessment (PA) release modeling, or

significant deviations should be evaluated to

determine their significance with respect to the

conclusions in the PA and technical evaluation

report (TER). The short-term performance of the

grouted vault is especially important to mitigate the

release of 

short-lived radionuclides such as Sr-90 from the

contaminated sand pads that could potentially

dominate the predicted doses from the TFF within

the first few hundred years.

3 Hydrological

Uncertainty

Relevant recent and future monitoring data and

modeling activities should continue to be evaluated

to ensure that hydrological uncertainties that may

significantly alter the conclusions in the PA are

addressed. If significant new information is found, it

should be evaluated against the PA and TER

conclusions.
Key Monitoring

Area (KMA) Area Description

44

4 Monitoring

During

Operations

Closure and postclosure operations (until the end of

active institutional controls, 100 years) will be

monitored to ensure that the 10 CFR 61.43

performance objective (protection of individuals

during operations) can be met.

5 Engineered

Surface Barrier/

Infiltration

Reduction

Idaho Nuclear Technology and Engineering Center

infiltration controls and the construction and

maintenance of an engineered cap over the TFF

under the Comprehensive Environmental Response,

Compensation, and Liability Act program should be

monitored to ensure that the PA assumptions related

to infiltration and contaminant release are bounding.

Reference:

DOE Idaho. DOE/NE–ID–11226, “Draft Section 3116 Determination Idaho Nuclear

Technology and Engineering Center Tank Farm Facility–Draft.” Rev. 0. Idaho Falls, Idaho: 

DOE Idaho. September 2005.
45

APPENDIX B

SUMMARY OF MONITORING ACTIVITIES
46

SUMMARY OF MONITORING ACTIVITIES

Performance

Objective Chapter Technical Review Activities Onsite Observation Activities

61.41 3 KMA 1

A. Review Sampling and

Analysis Plans (SAPs) and

Data Quality Assessments

(DQAs) for tanks WM-187

through WM-190.

B. Compare postcleaning

WM-182 tank inventory to

postcleaning tank inventories

developed for WM-187

through WM-190.

C. Compare vault WM-187

liquid sampling to vault 

WM-185 liquid sampling.

KMA 1

A. Observe postcleaning

sampling of tanks WM-187

through WM-190 against SAP.

B. Observe use of video

equipment to map out waste

residual depths in the cleaned

tanks to estimate waste residual

volumes.

KMA 2

A. Determine whether the

vendor-supplied slag has

sufficient sulfide content to

maintain reducing conditions

in the tank grout.

B. Determine whether slag

storage is sufficient to

maintain the quality and

chemical reactivity of the slag.

C. Assess the short-term

performance of the 

as-emplaced grout.

KMA 2

A. Evaluate the final grout

formulation for consistency with

design specifications.

B. Evaluate the 

risk-significance of any

deviations in the final grout

formulation from design

specifications.

C. Evaluate the

U.S. Department of Energy

(DOE) program for sampling,

testing, and accepting grout

materials.

D. Verify conditions of grout

placement in terms of

temperature and humidity.
47

Performance

Objective Chapter Technical Review Activities Onsite observation Activities

61.41 3 KMA 3

A. Evaluate and assess the

risk significance of any

variations in DOE PApredicted natural attenuation

of Sr-90 through the vadose

zone.

B. Evaluate and assess the

risk significance of any

increased estimates of

infiltration rates at the Idaho

Nuclear Technology and

Engineering Center (INTEC)

Tank Farm Facility (TFF)

above those assumed in

DOE’s PA.

C. Review hydrological

studies and monitoring data

for new and significant

information related to natural

attenuation at the INTEC TFF.

KMA 5

Evaluate and assess the

design, construction,

maintenance, and asemplaced performance of

engineered barriers installed

at the INTEC TFF against

DOE PA assumptions

regarding infiltration.

KMA 5

A. Remain cognizant of any

changes to the preliminary

design of the 

infiltration-reducing cap. 

B. Observe maintenance

activities of the cap.

PA Review

Review any revisions and

updates to DOE’s PA model to

assess the impact of changes

on conclusions regarding

compliance with the

performance objectives.
48

Performance

Objective Chapter Technical Review Activities Onsite observation Activities

Environmental Data Review

A. Review analytical data of

perched and saturated

groundwater at the INTEC

TFF.

B. Review hydrological

studies relevant to flow and

transport at the INTEC TFF.

Environmental Sampling Review

A. Observe the installation of

monitoring wells and

instrumentation.

B. Observe sampling activities.

 or

C. Rely on Idaho Department of

Environmental Quality (DEQ)

oversight program.

61.42 4 KMA 1

Compare post-cleaning 

WM-182 tank inventory to the

postcleaning tank inventories

developed for WM-187

through190.

61.43 5 KMA 4

A. Review DOE Idaho

radiation protection program

to ensure it is consistent with

that described in its waste

determination.

B. Review pathway analysis,

environmental data collected,

and DOE estimate of doses to

members of the public. 

KMA 4

A. Observe risk-significant DOE

closure activities. 

B. Observe air sampling

activities and DOE’s

meteorological program.

 or

C. Rely upon Idaho DEQ’s

environmental surveillance

program.

61.44 6 KMA 2

Review information on grout

formulation, placements, and

pours.

A. Observe signs of system

failure.

B. Observe system

performance after extreme

events.
49

CONTRIBUTORS
50

U.S. Nuclear Regulatory Commission Staff

Mark Thaggard

Chief, Performance Assessment Branch

M.S., Environmental Engineering, Johns Hopkins University

M.S., Applied Mathematics, Johns Hopkins University

M.S., Environmental Science, University of South Florida

B.A., Geology, University of South Florida

Hans D. Arlt 

Sr. Systems Performance Analyst 

Dr. rer. nat. (rerum naturalium), Natural Science, Technical University of Berlin 

B.S., Geological Sciences, University of Wisconsin 

B.A., International Relations, University of Wisconsin

Cynthia S. Barr

Systems Performance Analyst

M.S., Environmental Systems Engineering, Clemson University

B.S., Mathematics, College of Charleston

B.A., Political Science, College of Charleston

Michael Fuller

Project Manager

B.S., Marketing Management, Virginia Polytechnical Institute and State University

Center for Nuclear Waste Regulatory Analyses

Roberto T. Pabalan

Institute Scientist

Ph.D., Geochemistry and Mineralogy, The Pennsylvania State University

B.S., Geology, University of the Philippines