Text

LOW-LEVEL Radioactive Waste Research Program Plan
	ML19351A680
Person / Time
Issue date:	11/30/1989
From:	Lambert J, Odonnell E; NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	;
References
	FACA, NUREG-1380, NUDOCS 8912210251
	Download: ML19351A680 (67)
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NUREG-1380 i

Low-Level Radioactive Waste Research Program Plan L

L U.S. Nuclear Regulatory Commission.

Office of' Nuclear Regulatory Research i

E. O'Donnell, J.12mbert fearooq E,

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AVAILABILITY NOTICE Availabihty of Reference Materials Cited in NRC Publications Most documents cited in NRC_ publications will be available from one of the following

-sources:

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1.. The NRC Public Document Room, 2120 L Street, NW, Lower Level, Washington, DC 20555 a

2.

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Although the listing that follows represents the majority of documents cited in NRC publica-

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inspection and Enforcement bulletins, circulars, information notices, inspection and investi-l gation notices; Licensee Event Reports; vendor reports and correspondence; Commission l

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New York. NY 10018.

NUREG-1380 Low-Level Radioactive Waste Research Program Plan

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.; Manascript Completed: October 1989 Date Published: November 1989 '

E. O'Donnell, J. Lambert Division of Engineering Omce of Nuclear Regulatory Research

' U.S. Nuclear Regulatory Commission l

Washington, DC 20555 p** "*%

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ABSTRACT

'lhe Waste Management Branch, Division of Engineer-cludes schedules and milestones for completing the re-ing, Office of Nuclear Regulatory Research, has devel-scarch. Areas identified for investigation include waste oped a strategy for conducting research on issues of con-form and other material concerns, failure mechanisms cern to the U.S. Nuclear Regulatory Commission (NRC) and radionuclide releases, engineered barrier perform-in its efforts to ensure safe disposal of low-level radioac-ance, site characterization and monitoring, and perform-tive waste (LLW)(!he resulting LLW research program

. plan provides an mtegrated framework for planning the ance assessment.'1he plan proposes projects that (1)ana-11W research program to ensure that the program and lyze and test actual LLW and solidified LLW under its products are responsive and timely for use in NRC s laboratory and field conditions to determine leach rates LLW regulatory program. '!he plan discusses technical and radionuclide releases, (2) examine the short and and scientific issues and uncertainties associated with the long term performance of concrete-enhanced LLW bur-disposal of LLW, presents programmatic goals and objec8 ial structures and high-integrity containers, and (3) at-tives for resolving them, establishes a long terin strategy tempt to predict watermovement and contaminant trans-for conducting the confirmatory and investigative re-port through low permeability saturated media and search needed to meet these goals and objectives, and in-unsaturated porous media.

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J CONTENTS-3 r:i t-4 Page t"u Abstract....................................................................................

vii e

_ Foreword...................................................................................

ix Ack n owl ed gm e n t s...........................................................................

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I n t rod u c tio n................................. '............................................

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1.I' Pu rpose a nd Scope of Plan............................................................

1 1.2 Background.........................................................................

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' 2.

O rga n izat ion of Pl an......................................................................

5 2.1 Major Program Areas Selected for Research.............................................

9 2.2 S pecific O rgan izat ion.................................................................

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3.

Technical issues and User Needs...........................................................

9 3.1 I n t rod u ct io n.......................................................................

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3.2 Waste Form and Other Material Concerns..............................................

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~4 3.2.1 Wast e Characterization -......................................................

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3.2.2.

Testing Methods to Ensure Regulatory Compliance...............................

3.2.3 Decommissioning of Nuclear Facilitics.........................................

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-3.3 Failure Mechanisms and Radionuclide Releases..........................................

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' 3.3.1 Waste Form Performance....................................................

11 3.3.2 Radionuclide Releases.......................................................

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11 3.4 Engin eered Barrier Performance.......................................................

11-3.4.1 Imng. Term Performance of High-Integrity Containers............................

11 3.4.2 ImngIrcrm Concrete Performance...........................................

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~3.4.3 Long-Term Cover Performance...............................................

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3.5 Site Characterization and Monitoring..................................................

- 3.5.1 Sit e Charact erizat io n.......................................................

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3.5.2 M o n it orin g..............................................................

1 12 3.6 Performance Assessment.......................................

3.6.1 Performance Assessment Pathway Model Evaluation.............................

12 3.6.2 Radionuclide Source Term.................................

12 13

-l 3.6.3 Transport of Radionuclides and Chemicals at LLW Disposal Sites...............

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4.

' Summary of Program Strategy..................

L 13 4.1 Waste Form and Other Material Concerns a

4.2 Failure Mechanisms and Radionuclide Releases....

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14 4.3 Engineered Barrier Performance.......

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. CONTENTS (Continued)-

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4.4 Site Characterization and Monitoring...................................................

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. 4.5 Performa nce Assessm ent.............................................................

14' 5.

Aksessment of Program Pace and Priorities...................................................

15 6.

Integration with Other Research....................

'15 6.1 - I n t rod uct ion................................y............................

15 6.21 Na t iona l Progra m s '..................................................................

15 6.2.1 D e part m e n t of E n e rgy.......................................................

15 6.2.2 Environmental Protection Agency..............................................

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6.23 ~ U.S. G eological S u rvey......................................................

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6.2.4 St at e Progra ms..............................................................

15 63 I n te rnational Progra ms...............................................................

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63.1 B ila t eral Exchanges..........................................................

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63.2 INTRAVAL...............................................................,

16 Appendix A N M SS User Need Lett er...........................................................

A-1 a

Appendix B Detailed Discussion of Strategy.....................................................

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FIGURES 1.

Key LLW disposal facility development milestones.................................i..............

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Technical uncertainties and research needs associated with low. level radioactive waste disposal 4

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Program elem e n t struct u re...................................................................

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Overall I.LW research integration.............................................................. 10 TABLES

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LLW disposal regulatory requirements of 10 CFR Part 61..........................................

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2.

1.inkage between re

'v in Chapter 4......gulatory requirements of 10 CFR Part 61 and research program strategy set outj 6

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Linkage between LLW research needs identified b Chapter 4 und Appendix B..................y NMSS and research program presented in 8

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FOREWORD The Waste Management Branch, Division of Engineer-in the spring in conjunction with the annual updating of ing, Office of Nuclear Regulatory Research (RES) is in the NRC's Five Year Plan. Revisions shall be made, as the process of developing an integrated framework for necessary, and they shall be done in consultation with planning the low-level radioactive waste (ILW) research NMSS, the Waste Management Review Group, and the program to ensure that the program and its products are Advisory Committee on Nuclear Waste, responsive and timely for use in the 11W regulatory pro-gram. As a first step in this process, we have written this it should be noted that this plan describes an LLW man.

LLW Research Program Plan, which presents an inte-agement research program that is more than a factor of grated strat egy for conducting ongoing and new LLW dis-

- three greater in resource level than the current FY 19%

posal research. Much of our planning in this area was budget for the program. The scope and the pace of the based on a user need letter (Appendix A)provided by the actual FY 1990 LLW research program falls considerably Division of low-Level Waste Management and Decom.

short of meeting all the needs of the user office as well as missioning (LLWM) of the Office of Nuclear Material their schedule.

Safety and Safeguards (NMSS) and followup discussions with LLWM to coordinate this plan with that office. Our During FY 1990, in preparation for the first update of this planning process included management review by the Nu-plan, we expect to emphasize interactions with (1 the De-f clear Regulatory Commission's Waste Management Re.

partment of Energy's (DOE) LLW program and (2) the view Group and review by the Commission's Advisory appropriate State organizations. Research prioritization Committee on Nuclear Waste.The comments from these will be done in close coordination with NMSS.

groups have been included in this plan.This initial version is the baseline program plan for the program in FY 1990 The publication of this program plan has been announced z

and beyond. It is intended that this baseline plan will be a in the Federal Register. Comments and suggestions are living document for a stable program with a framework welcome and can be sent to the authors in writing or by that is sufficiently flexible to permit revisions arising from telephone (301-492-7000).

program changes that may be needed during the course of the research prograia.The current edition of the plan has been provided to RES's oversight committee, the Nuclear Melvin S. Silberberg, Chief Safety Research Review Committee (NSRRC), for their annual review of the RES programs. Comments and ad.

Waste Management Branch vice received from the NSRRC will be factored into the Division of Engineering next edition.The program plan will be revisited annually Office of Nuclear Regulatory Research l

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ACKNOWLEDGMENTS The authors want to express their appreciation to their tions on waste characterization, testing methods, and co!!eagues in the Waste Management Ilranch for their waste form performance. We also want to acknowledge contributions to this plan, specifically Linda A. Kovach the assistance of Emarsha S. Hodge and Evelyn Queen in

for the sections on radionuclide releases and radionuclide the preparation of this manuscript and Louise Gallagher source term, Timothy J. McCartin for the section on per-for her aid in its technical editing. Janet Thot Thompson formance assessment pathway model evaluation, Thomas directed preparation of the graphics, l'inally, the plan also -

J. Nicholson for the section on site characterization and benefited from review by the licensing staff in the Office monitoring, Jacob Philip for the sections on long-term of Nuclear Material Safety and Safeguards, specifically performance of high integrity containers and long term John J. Surmeier, R. John Starmer, James A. Shaffner, performance of concrete, and Phillip R. Reed for the sec-Joseph D. Kane, and Leroy S. Person.

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1. INTRODUCTION necessaiy to support the NRC's and the Agreement States' upcoming safety evaluations of low-level waste disposal facilities and decommissioning projects. Part of

1.1 Purpose and Scope

of Plan the research program set out in the plan is intended to further refine the technical, scientific, and regulatory As the agency charged with the licensing and regulation of bases for LLW shallow land burial in general and as it is disposal of " commercial nuclear materials and activities" c nducted today at the three operating LLW disposal fa-

' (i.e., materials and activities licensed under the Atomic cilities. Sinc,c it appears likely that the next generation of Energy Act of 1954) including low level radioactive waste L.LW facilities will include the addition of sigmficant engi-(LLW), NRC's task is to establish and implement the nected enhancements, the plan also proposes research framework for licensing all aspects of LLW disposal facil-that specifically focuses on resolym, g the techmcal and sci-i;y siting, design, construction, operation, and closure, entific issues associated with engmeered enhanced dis-Within that framework, the NRC carries out oversight P 8"I' and review to ensure that LLW disposal will present no undue risk to the public health and safety or the environ.

The plan provides schedules and milestones for conduct-ment.

ing the research with a view to when the resulting infor-mation or analytical tools will be needed by the regulatory To meet its LLW disposal regulatory responsibilities, the staff, with particular emphasis given to those licensing ac-tions that flow from milestones the States ruust meet m NRC requires technical data and methods for evaluating the demonstrations made by licensees and license appli-the Low-Level Radioactive W,aste Policy Amendments cants that a proposed LLW disposal facility will isolate ra-Act of 1985 (LLRWPAA). (See Fig.1 for schedule of ma-

- dioactive materials over the period of time that these y mi stones) wastes remain dangerous to the public. The data and methods that the NRC uses to review the submittals of This document provides the planning framework for an licensees and license applicants must be independent of integrated, stable, co'mprehensive research program for the assessment techniques and data bases developed by 11W. It is intended that the plan be modified, as neces-those licensees and applicants in support of their submit-sary,in response to changes in the direction of the overall tals.The complex interrelated technical issues of concern LLW prograin in a manner consistent with maintainingan include maintaining the integrity of the waste form and appropriately viable research program, waste container, understanding the interaction of the waste form and container with the environment at the dis-posal site, and understanding the movement of radioac-L2 Background live material within the disposal facility and through the environment during and after the design life of the engi-Ilefore discussing the research strategy, it is useful to dis-neered components of the disposal system. He purpose cuss some of the factors associated with the regulation of of NRC s LLW research program, both confirmatory and mvestigative, is to furmsh the necessary technical under-LLW disposal that make the research necessary.

standing of the issues and those independent data and methods consistent with the regulatory needs of the li.

Successfully regulating the safe disposal of LLW requires censing office to ensure effective radioactive waste man-that the NRC staff have an applied understanding of a agement and disposal.

complex set of scientific and technical variables, as well as the capability to anticipate the outcome of their interac-

- Thisdocument presentsa plan for LLW management and tions. With this understanding and capability, the NRC disposal research to be performed by the Waste Manage-stahwha& topaluate thpecW Wormance f a pr p sed LLW disposal facility against the perform-ment Ilranch (WMB), Division of EnE neering (DE), in i

ance objectives m 10 CFR Part 61, Licensing Require-the Office of Nuclear Regulatory Research (RES).,Ihe ments for I2md Disposal of Radioactive Waste," to deter-research program presented in this plan was developed in mine whether the facility will be capable of isolating the response to a request for regulatory support from the of-hazardoJs components of LLW from the environment.

fice with the funct!onal responsibility for licensing LLW The NRC licensing staff needs information regarding the disposal, the Division of Inw-Level Waste Management scientific and technical issues described in Chapter 3, and Decommissioning (LLWM)in the Off,ce of Nuclear i

" Technical Issues and User Needs," of this document to Material Safety and Safeguards (NMSS). (Reference evaluate the long-term performance of a facility. Licens-NMSS user need letter m Appendix A.)

ing decisions require a thorough understanding of the na-ture and form of the LLW intended for disposal, the sur-The plan provides a long-term strategy for conducting face and subsurface characteristics of the site where both the investigative and confirmatory research that is disposal is to occur, and how the various design features of l

1 NUREG-1380

1985 1986l1987l1988l1989 1990l1991l1992l1993l1994l1995 1996 i

KEY MILESTONES States must ratify Compact legislation or certify intent to develop an 1.LW disposal site.

Access to existing L1W sites may be denied.

States / Compacts must develop a siting plan.

Access to existing sites may be denied.

V5 A complete LLW disposallicense application must be filed or certification provided to the N State will manage the waste after 12/31/92.

Access to existing sites may be denied.

All LLW disposal license applications must be filed and determined to be complete by the NRC.

V8 State / Compact assumes responsibility for low-level waste disposal or must repay a portio surcharge to the generators.

State / Compact must take title / possession of low-level waste.

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Figure 1 Key LLW disposal facility development milestones from the Imw Level Radioactive Waste Policy Act Amendments of 1985 (LLRWPAA).

All of the States are required by the low-Level Radioactive Waste Policy Act Amendments (ILRWPAA) to develop LLW disposal sites according to this schedule. Any regulatory or licens-ing actions required of NRC relative to the development of these sites will also be driven by these milestones. The goal of this plan is to ensure that necessary LLW disposal supporting research is available as needed by the L1,W disposal licensing staff to meet NRC's Lt.RWPAA regulatory responsibilities.

NUREG-1380 2

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the planned disposal facility will work'with the site to en.

2.

Importance of Understanding the Site and Dis.

hance its isolation potential. Since the research program posal Environment presented in this plan is intended to assist the staff in gain-ing the necessary understanding, some general discussion The LLW disposal site environment contributes an.

of the variables that come into play in LLW disnosal and other set of complex variables that, together with the their interactions is provided here for perspective.

characteristics of the LLW, must be understood in order to assess the performance of a proposed dis-posal facility. The site for the disposal facility deter-

1. _ Importance of Understanding the Waste and the mines the physical and hydrologic environment into 1

_ Waste Form which the waste must be placed and in which it must maintain its integrity during the hazardouslife of the Clearly questions about the adequacy of LLW dis-LLW. Figure 2 is a schematic of a shallow land dis-posal begin with the LIAV itself. The nature and p sal facility. The schematic indicates some of the form of the waste determine its potential source natural and engineered characteristics of the site term and its potential for release of radioactivity or that affect the stability and long term performance j

other hazardous materials, the overall long-term of the individual components as cell as the overall i

stability of the disposal site, the preferred engi-LLW disposal facility. The major pathways for po-l nected enhancements, and the likely pathways ior tential long-term radiological exposure to the pubhc j

release to the environment.

are also shown on the schematic and include poten-tial leaching and transport of the waste by and into the ground water, deliberate or inadvertent human Fundamental to the problem of providing sale dis.

intrusion into the disposed waste, intrusion and dis-posal for LLW is that the term " low-level waste" re.

persion by plants and animals, long term crosion of fers to a wide range of radioactive wastes with an the site by wind or water, and resulting radionuclide equally wide range of physical and chemical chan c.

transport by surface water or the air.

teristics. All industries; hospitals; medical, educa-Because it is important to NRC's licensing efforts, tional, or research institutions; private or govern-WMD is proposing research that will further expand ment laboratoties; or facilities forming part of the our understanding of the complex disposal environ-nuclear fuel cycle (e.g., nuclear power plants, fuel ment so the staff will be able to better predict how it fabncation plants) using radioactive materials as a affects the release of radionuclides and other haz-part of their normal operational activities generate ardous substances from the waste, and how it deter-so-called low level radioactive waste just as they mines the movement of those materials within the generate other types of hazardous and nonhazar.

site and into the adjacent environment. (See Sec-dous wastes. LLW consists of the radioactive matere tions 4.3, " Engineered llarrier Performance," and als themselves and other matenals that have been P 4.4,"S te Characterization and Monitoring," and the contact with radioactive matenals and are contami-j corresponding sections of Appendix B for discussion nated or suspected of being contammated. It is gen' of the research proposed for these areas.)

l crated in many waste types, forms, and amounts. It ranges from trash that may be only slightly contami-3.

Regulatory Framework for LLW Disposal nated with radioactivity to highly radioactive matcri-l als such as activated structural components from nu.

NRC makes its LLW disposal licensing decisions clear power reactors.The form of the waste may be within the regulatory framework of 10 CFR Part 61, solid, liquid, or gaseous and it may consist of a variety which sets the terms and conditions for licensing the of chemical forms. LLW ranges in activity from disposal of LLW. Part 61 contains procedural re-thousands of curies per cubic meter to less than a quirements and general performance objectives ap-few microcuries per cubic meter.

plicable to any method of shallow land disposal of LIAV. (See Table I for Part 61 regulatory frame-work.) It also contains specific technical require-Because of the variability of LLW, there are issues ments for ensuring that the performance objectives that remain to be addressed in order for the NRC are met for near surface disposal of radioactive i

staff to have the full complement of information im-waste in the uppermost portion of the earth. The portant for LLW disposal performance assessment.

performance objectives in Part 61 Subpart C specify Thus, WMil's research strategy is to collect, evalu-that shallow land disposal facilities for LLW must be 1

ate, and test actual waste streams to thoroughly sited, designed, operated, closed, and controlled characterize the chemical and physical nature of after closure in a manner that protects the general LLW. With this information, the NRC staff will be population from releases of radioactivity during and better able to predict how the LLW will respond in after operation, the workers onsite from releases the disposal environment.

during operation, and the inadvertent intruder l'

3 NUREG-1380

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I Figure 2 Technical uncertainties and research needs associated with low-level radioactive waste disposal.

i The uncertainties begin with the radionuclide and chemical content of the waste and its long-term performance. Engineered barriers may be used to provide structural stability to the disposal facil-ity, to contain waste, and to keep water from entering disposal units. Performance assessment l-entails evaluating everything from waste package degradation to water entry, performance of engi-neered barriers, role of the geologic environment in containing waste, radionuclide migration, and biologic uptake into the food chain to humans. These uncertainties are outlined in Chapter 3 and a strategy for addressing them will be found in Chapter 4.

I NUREG-1380 4

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W Table 1 LLW disposal regulatory requirements of 10 CFR Part 61.

Subpart C-Performance Objectives Subpart D-Technical Requirements Protection of general population

Site suitability e

Worker protection e Site design e

e Inadvertent intruder protection e Operations and closure i

1.ong-term protection-stability following closure o Environmental monitoring j

e l

e Waste classification l

1 e Waste characteristics i

from releases after closure. Section 61.41 provides tact the LLW will have with surface water and j

the overall performance objective for the safe dis-ground water and should not be affected by tectonics l

posal of LLW in terms of doses-limiting the dose to or volcanism during the period it is to provide isola.

any member of the public from any release to less tion.

l than 25 millirems /yr for the whole body, 75 61.51 Site Design Requirements-A site must be l

millirems /yr to the thyroid gland, and 25 millirems /

e yr to any other organ.

designed to provide the stability required to provide long-term isolation of waste, to improve and supple-Since the performance objectives serve both as ment the natural site, and to direct water away from short term and long term regulatory objectives for the site.

LLW disposal, they are the basis for performance as-sessment for any LLW disposal licensing decision 61.52 Operating Facility Requirements-During e

and thus are the driving force for the research pro-operation, LLW is to be segregated into categories posed in this plan. (See Table 2 for the linkage be-A, B, and C, with different packaging and handling l

tween Part 61 and the I LW research strategy pre-for each; intruder barriers, including engineered en.

sented in Chapter 4, " Summary of Program hancements and covers, must be built to provide iso-

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Strategy," of this document.)

lation for 500 years, and future subsidence is to be reduced.

The technical requirements in Part 61 Subpart D also l

serve as impetus for the rescarch program proposed in For each LLW disposal license application, the NRC this strategy plan. (Table 2 also shows how the researcl\\

must l'c capable of evaluating the applicant's assertions proposed in the plan relates to the technical require-that the proposed disposal facility will meet the technical

- ments ) The technical requirements are established for requirements of Subpart D in order to determine if the cach stage in the life of a potential near-surface LLW dis-facility will pcrform in a manner consistent with the per-posal facility, including the preoperational phase, opera-formance objectives in Part 61. Where scientific or tech-tional phase, closure phase, obsen ation and maintenance nical issues relating to major aspects of LLW disposal that phase, and finally for the period of institutional control.

could potentially impact the public health and safety re-The major technical requirement driving the LLW re-main unresolved, NRC's ability to make the most search plan is paragraph 61.50(a)(2), which requires that informed licensing decisions is reduced. The research an acceptable disposal site must be capable of being char-proposed in this plan will help resolve some of the re-acterized, modeled, analyzed, and monitored. If the NRC maining uncertainties.

is to be in a position to review a license application, it must have its own capability to characterize, model, and ana-lyze the disposal facility information presented.

2. ORGANIZATION OF PLAN Other major tcchnical requirements in Subpart D that 2.1 Major Program Areas Selected for provide direction for the research strategy include:

Research o

61.50 Site Suitability Requirernents-A disposal site The LLW research program plan has been structured to must be selected and designed to minimize the con-closely correspond to the areas for research identified in 5

NUREG-1380

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ss Table 2 Linkage between regulatory requirements of10 CFR Part 61 and research program strategy set out in Chapter 4.

10 CFR Part 61 Regulatory Requirements Addressed Ily Subpart C-Performance oldectives Protection of general population Sect. 4.5 Performance assessment e

1 o Worker protection j

Inadvertent intruder protection Sect. 4.3 Engineered barrier performance i

Ilmg term protection-stability following closure Sect. 4.2.1 Waste form performance l

e Sect. 4.3 Engineered barrier performance Sect. 4.4 Site characterization and monitoring Subpart D-Technical requirements Site suitability Sect. 4.4 Site characterization and monitoring e

'* Site design Sect. 4.3 Engineered barrier performance

'. Operations and closure Sect. 4.4 Site characterization and monitoring 1

Etivironmental monitoring Sect. 4.4 Site characterization and monitoring l

e

Waste classification Sect. 4.1 Waste form and other material concerns

[

Waste characteristics Sect. 4.2 Failure mechanisms and radionuclide -

i releases

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1 the June 8,1988 NMSS user need letter (enclosed as Ap-in the plan is logically consistent with the NMSS break-pendix A). In that letter NMSS identified its LLW re-down and represents a compromise between the NMSS search needs based on the information and analyses re.

proposed areas for needed research and the process-quired to demonstrate compliance with NRC regulations oriented program area structure of the existing research 10 CFR Parts 20,30,40,50,61,70, and 72.The letter set program.-

out five program areas in which LLW research was seen as necessary in order for NMSS to carry out its regulatory While the program area headings used in the plan differ j

and licensing functions. The ateas were: (1) LLW man-and some individual research needs may be discussed un-agement and treatment, (2) failure mechanisms and der a different heading from that used in the NMSS radionuclide releases,(3) site characterization and moni-letter, almost every need identified by NMSS has been toring, (4) performance assessment, and (5) decommis-addressed in the plan and in a manner that we believe is sioning.

reasonable and responsive. (Table 3 presents a compari-son between the research needs identified in the NMSS This LLW research program plan also focuses on five ma-letter and the research proposed in Appendix 11 to this jor program areas where research is needed: (1) waste plan.)

form and other material concerns, (2) failure mechanisms and radionuclide releases, (3) engineered barrier per.

In addition to the specific research requested by NMSS,

- formance (4) site characterization and monitoring, and the plan addresses additional prospective LLW research (5) performance assessment. (See Fig. 3.) Program areas 2 that the RES staff believes is needed over the next 5 years and 4 are the same areas identified by NMSS; the other and beyond to complement and supplement the work three are not. The breakdown of research program areas desired by NMSS.

l NUREG-1380 6

i I

LLW RESEARCH PROGRAM PLAN 1

l s

PERFORMANCE-i ASSESSMENT M

I l

I i

WASTE FORM AND FAILURE MECHANISMS SITE OTHER MATERIAL AND RADIONUCLIDE CHARACTERIZATION ENGINEERED BARRIER CONCERNS RELEASES AND MONITORING RFORMMCE

[

i 2

E 8,

Figure 3 Program element structure.

E' J

4 v v

- - ~

- - = -

s

[

]

l i

Table 3 Linkage between LLW research needs identified by NMSS and research program presented in Chapter 4 and Appendix B.

Research Needs Parts of Appendix B and Chapter 4 of the identified in NMSS User Need Letter Plan Addressing NMSS Research Needs A. Low. Level Waste Management and Treatment 1.

Process control parameters and test methods B.I.2 Testing methods to ensure regulatory for qualifying solidified waste compliance (Section 4.1)

B.2.1 Waste form performance (Section 4.2) 2.

Waste receipt inspection test methods B.1.2 Testing methods to ensure regulatory compliance (Section 4.1) 3.

Ilazard analysis for 1.LW 4.

Waste characterization and assessment ~

B.I.1 Waste characterization (Section 4.1) 5.

Alternative techniques for LLW treatment B. Failure Mechanisms and Radionuclide Releases 1.

Radionuclide release models for LLW B.2.1 Waste form performance (Section 4.2)

U.2.2 Radionuclide releases (Section 4.2) 2.

Effects of chelating agents and other constituents B.1.1 Waste characterization (Section 4.1) on decontamination waste releases B.2.1 Waste form performance (Section 4.2)

B.2.2 Radionuclide releases (Section 4.2) 3.

Screening tests for LLW form and container B.3.1 Long-term performance of IUC stability (Section 4.3) 4.

Infiltration evaluation methodology for LLW B.3.3 long-term cover performance disposal facilitics (Section 4.3) 5.

Archival trench program 6.

Long-term performance of concrete structures B.3.2 Long-term concrete performance (Section 4.3) 7.

Development of crosion protection design B.3.3 Long-term cover performance (Section 4.3) criteria for long-term stabili7ation 8.

Imad deformation characterization and modeling B.3.3 Long-term cover performance (Section 4.3)

C. Site Characterization and Modeling

1.. Unsaturated zone monitoring B.4.1 Site characterization (Section 4.4)

B.4.2 Monitoring (Section 4.4) l 2.

Naturallandform modifications B.4.1 Site characterization (Section 4.4) l l

D. Performance Assessment l

1.

Performance assessment scenario evaluation B.5.1 Performance assessment scenario evaluation (Section 4.5) 2.

Transport behavior of C-14 and 11-3 B.5.3 Trtmsport of radionuclides and chemicals at ILW disposal site (Section 4.5) l 3.

Geochemical transport of contaminants at B.5.3 Transport of radionuclides and chemicals L.I.W disposal sites at LLW disposal site (Section 4.5) l NUREG-1380 8

l l

V i

Table 3 (Continued)

Research Needs Parts of Appendix B and Chapter 4 of the i

.ide;tified in NMSS User Need Letter Plan Addressing NMSS Research Needs

- E. Decommissioning 1.

Assessment of technology, safety, and cost of B.I.3 Decommissioning of nuclear facili%s decommissioning power reactors (Section 4.1) 2.

Assessment of technology, safety, and costs of U.l.3 Decommissioning of nuclear facilities decommissioning nonreactor facilities (Section 4.1) 3.

Capabilities of onsite reactor radwaste systems to process decommissioning wastes 2,2-Specific Organization.

3. TECHNICAL ISSUES AND USER NEEDS Chapter 3, " Technical Issues and User Needs," identifies 3.1 Introduction

-what specific 11W research is actually needed. It lists

,The research needs outlined in this chapter are based on a

. technical or scientific issues and user needs within each of careful review of the NMSS user need letter (Appendtx the five program areas that impact NRC's LLW disposal A) and discussions with NMSS management and staff licensing activities and that we believe should be resolved subsequent to the receipt of the user need letter.The re-

.for the most effective regulation of LLW management search needs have been integrated into a framework of and disposal. The importance assigned by the regulatory technical and scientific issues and are presented in that i

staff to the resolution of these issues actually determines way (see Fig. 4). This approach is being used because, in i

the need for research, most of the LLW program areas, research needs flow from the state of technical or scientific uncertainty in a specific area of technology and reflect a recognition of the

- Chapter 4, " Summary of Program Strategy," sets out magnitude of the regulatory or licensing problems caused l:

' RES's general strategy for meeting the needs identified in by the uncertainty. In most cases, it is the uncertainties each of the five program areas in Chapter 3.The general and any corresponding threat to the public health and strategies either propose research to acquire necessary.

safety that provide a firm basis for identifying research information or to develop necessary analytical tools or needs, for judging if further research is needed, for deter-methods. Basically, Chapter 4 tells where we are now, mining the level of research effort needed, and for deter-

- - 8

hen a specific piece of research has provided the where we want to be, and how we plan to get there.

mformation ongmally needed or has reduced the level of uncertainty sufficiently for regulatory purposes. Finally, an unresolved technical issue frarnework and perspective Appendix B amplifies the general strategy for each of the is useful for research prioritization m conjunction with five program areas provided in Chapter 4, with more de-us s assessment d pnonty, tailed research plans for resolving the individual technical and scientific issues and for addressing user needs associ-It should be noted that not all the areas listed in this chap-ated with the five program areas. Appendix B also ad-ter are being proposed for research at this time, but they dresses RES's goals for each research program; summa.

have been included because they are part of a compre-rizes our current understanding of the technical and hensive research plan in support of LLW disposal regula-scientific issues involved; provides the regulatory basis for tory activities.

the research proposed; explains how the information de-3.2 Waste Form and Other Material sired from the research is expected to be used; sets out the steps to be taken to develop the information and resolve Concerns

. the uncertainties; explains the integration between each 3.2.1 Waste Characterizat. ion project to others described in the plan; and sets out a schedule for the completion of the proposed research and If the NRC is to anticipate how LLW will behave in the i

SUBJECT:

USER NEED STATEMENT FOR THE LOW-LEVEL RADI0 ACTIVE WASTE MANAGEMENT PROGRAM Throcgh ongoing interactions with DOE, States, Regional Compacts, and technical assistance contractors, staff in the Division of Low-Level Waste Management and D:comissioning (LLWM) has identified general and specific research needs that should be fulfilled to support safety evaluations of low-level waste management facilities and decomissioning projects. We are transmitting these n:eds to you in the enclosed NMSS Statement of LLWM Research Needs. As you are aware, the Executive Director for Operations recently assigned HMSS the 1

r:sponsibility to coordinate NRC's program for reactor and non-reactor d:comissioning. As a result, we identified research needs.in the decomissioning area,through consultation with HRR staff to support implementation of NRC's decomissioning program.

The enclosed statement identifies regulatory issues that require investigative and confirmatory research to provide technical support for licensing assessments and safety reviews in the LLWM program. We endorse the enclosed projects for inclusion in RES's Low-level Waste Management Program. Although ongoing research already promises to fulfill some of the enclosed needs, future RES projects should address the other research needs identified in the statement. Results of the research conducted to fulfill these needs will assist us in assuring the safety of Icw-level waste management facilities and d:comissioning activities.

Briefly, LLWM staff needs research products that can be used to support staff in developing guidance about site characterization, performance assessment, decommissioning plans, cost estimates for decomissioning, and financial assurance, and in performing independent evaluations of license ap)lications l

and decomissioning plans. The objectives of the research should be to assess the capabilities, limitations, and uncertainties of evaluations of the

).

cperation and safety of LLW disposal facilities and decomissioning projects, including the following activities:

1.

Identifying failure mechanisms of engineered and natural barriers for I

low-level radioactive waste (LLW) isolation.

1 2.

Developing methods to assess the release and transport of radionuclides and other constituents from LLW under normal and failure modes over periods of hundreds to thousands of years.

l l

4_3 NURiiG-1380 J

r

?

3.

Evaluating lessons learned f rom exi, ting waste disposal sites regarding the ability of ' natural and engineered barriers to isolate radioactive waste.

4 Assessing management, treatment, and packaging of LLW to ensure safe operations and provide for long-term isolation of the waste after disposal.

5.

Assessing the technology, safety, and costs of decommissioning power reactors and non-reactor nuclear facilities.

We would be happy to work with your staff to refine the definition of the enclosed research needs further as specific projects are developed. LLWM staff will continue to work closely with RES to ensure that existing and future research is consistent with identified research needs and priorities, research activities are integrated with the LLWM Technical Assistance Program, and RES products are provided in a timely manner consistent with NRC's progrannatic needs. LLWM staff will also continue to assess confirmatory research needs and update the HMSS Statement of LLWM Research Needs accordingly.

In addition, we encourage RES staff to continue to discuss with us specific ideas about research projects to support NRC's LLWM program.

Please contact John J. Surmeier at telephone extension 20588 if you have any questions or comments about the enclosed NMSS Statement of LLWM Research Heeds.

(Original Signed byg i

Hugh L. ' Thompson, Jr., Director Office of Nuclear Material r

Safety and Safeguards

Enclosure:

NMSS Statement of LLWM Research Needs

'I I

l O

^~4 NilltliG-1380

INCLOSURL NMS$ STATEMENT Of LLWM RESEARCH HEEDS Hay 1988 The following research needs should be fulfilled by investigative and confirmatory research projects to support NRC's conduct of independent reviews and evaluations of license applications for low-level radioactive waste (LLW) disposal and decommissioning for nuclear f acilities. These research needs have been identified by LLWM based on assessments of the information and analyses required to demonstrate compliance with NRC regulations in 10 CFR parts 30, 40, 50, 61, 70, and 72. LLWM staff distilled these needs from a broader list of research needs based on the following criteria:

1.

What specific product (s) will the research provide?

2.

What can LLWM staff do with the product (s) that it could not 4

otherwise accomplish without the product and how does the use of the product (s) support the accomplishment of NRC's mission?

3.

Who and how would the product (s) be used in licensing and reviewing 1

the safety of LLW management facilities and decommissioning projects?

The research program should provide results to LLWti staff in the form of practical tools, methods, and information to directly support regulatory reviews and evaluations.

Research results, both interim and final, should be provided to LLWM staff in a timely fashion to facilitate compliance with existing agency schedules for the LLW and decomissioning programs. Research in the LLWM program area should assess the capabilities, limitations, assumptions, and uncertainties associated with evaluation of the operation and t.afety of LLW disposal facilities and decomissioning projects. Research projects should be product oriented and should clearly identify regulatory decisions that cannot be made or adequately supported in the absence of the products.

The LLWM research program should address the research needs listed below, which have been categorized into (A) LLW Hanagement and Treatment, (B) failure l

Mechanisms and Radionuclide Releases, (C) Site Characterization and Monitoring, l

(D) performance Assessment, and (E) Decomissioning.

Each need has been l

assigned an "A" or "B" priority with "A" indicating the highest priority.

In i

the event that all needs cannot be fulfilled, the priority ratings should be used in developing a research program that fulfills the highest priority needs.

priorities within the " A" and "B" groups should be determined by LLWM and RES management as the specific projects are developed to fulfill the needs.

A-5 NtlRIRi-1380

A.

LOW-LEVEL WASTE MANAGEMENT AND TREATMENT 1.

Process Control Parameters and Test Methods for Qualifying Solidified Wastes (Priority A)

Research needs to be conducted to identify critical process control parameters for successful dewatering and solidification of LLW.

These parameters would be used in regulatory reviews of process control programs and vendor topical reports. The research should also recomend suitable test methods for measuring critical parameters to ensure that they are within specified limits.

The parameters and test methods should be identified in such a manner that they can be incorporated by LLWM staff into review criteria and technical positions.

2.

Waste Receipt inspection Test Methods (Priority A)

Research is needed to develop and recomend test methods for inspection of LLW received at LLW disposal facilities. Receipt inspections at existing sites verify compliance with only the free Liquid and Solidification requirements.

Guidance about additional testing is needed to identify reliable, safe, and nanomical test methods for receipt inspections of LLW to verify compliance with do CFR Part 61.8@and disposal site waste form requirements, in addition, such test metnoas are needed to perform as received inspections to ensure compliance with Mixed LLW disposal requirements. The research should develop new test methods or recomend existing methods to assess and confir.h important LLW characteristics in receipt inspections.

3.

Hazard Analysis for LLW (Priority B)

Research is needed to develop a standardized approach for assessing radiological, chemical, operational, and biological hazards of wastes. License conditions at the existing sites currently require a hazard analysis for LLW that may exhibit non-radiological hazardous properties. The NRC has not, however, identified methods to conduct the hazard analysis or assessed these methods to ensure confomance with other requirements (e.g., minimize worker exposure). The research should assess alternative methodologies to conduct a hazard analysis and recommend a preferred hazard analysis methodology, 4.

Waste Characterization and Assessment (Priority B)

Research is needed to collect samples of activated materials, to assess the distribution and transport of contaminated materials throughout power reactors and non-reactor nuclear facilities, and to evaluate the distribution of long-lived nuclides in low-level and decomissioning wastes. Because several radionuclides of concern are difficult to measure operationally, licensees (e.g., nuclear power plants) typically estimate the radionuclide content within wastes by indirect means. Licensees radiochemically analyze samples of waste streams and develop scaling factors that relate concentrations of alpha-and beta-emitting nuclides to concentrations of gam-emitting nuclides.

Results of sample analyses are frequently given as the lower limit of detection (LLD)

Using scaling factors, licensees estimte the cuantities of radionuclides in NURiiG-1380 A-6

i actual waste containers by various methods, ranging from gama spectral analysis of grab samples to correlations with dose rate measurements using survey meters. Uncertainties about the distribution of long-lived nuclides in LLW could delay licensing new disposal sites. Research products should include (1) an analysis of samples of decommissioning and low-level wastes to determine the significance of selected long-lived nuclides (e.g., Mo-93, Ag-108m, Cl-36) other than those listed in 10 CfR.$61.55; (2) an assessment of the adequacy of existing radiuchemical and analytical techniques (e.g., dispersion, bias, r:peatability, sensitivity) with emphasis on radionuclides such as 1-129, Ni-59, and Ni-63; (3) an assessment of the present and potential significance cf licensees making overly conservative estimates of the concentrations of radionuclides such as 1-129 and Tc-99; (4) generic scaling factors for use when sample results are below the lower limit of dectection (LLD), and (5) an evaluation cf the adequacy of existing dose-to-curie measurement techniques.

The research should also provide recomendations that can be used by LLWM staff as a basis for modifications to the Technical Position and Regulatory Guide on Waste Classification or for a potential rulemaking in the area of waste classification.

5.

Alternative Techniques for LLW Treatrnent (Priority B)

Research is needed to identify alternative treatment techniques for LLW in those situations where conventional techniques are unecceptable, for example, some oil and organic solvents wastes have high activities that preclude incineration as a suitable treatment option or disposal as a below regulatory concern waste. The research should identify and assess the feasibility of alternate treatment techniques. The research results should be provided to LLWM in a form suitable for incorporation into technical guidance about LLW canagement.

B.

FAILURE MECHANISMS AND RADIONUCLIDE RELEASES 1.

RadionuclideReleaseNodelsforLLW(Pr.iorityA)

R: search is needed to establish radionuclide release models for LLW, including high volume heterogeneous trash and high activity activated metal components.

This research should include the following activities:

(1) characterization of the processes that control radionuclide release from LLW, (2) development of a mechanisticmodelormodelstosimulatethereleaseprocesses,and(3) validation of the model(s) using existing information to the maximum extent practicable. Current relationships assume that radionuclide release from LLW will be dominated by diffusion. Corrosion and dissolution, however, may also significantly enhance the release of radionuclides from LLW. Therefore, the I

I research should characterize the processes that control radionuclide release and develop mechanistic models that describe the physical and chemical processes that control radionuclide releases from LLW.

The models should be developed in a manner and on a schedule so they can be implemented by LLWM staff in support of licensing and topical report reviews.

A-7 NURl!G-1380

lo the maximum extent practicable, the models should be validated based on experimental data f rom laboratory leaching experiments and field lysimeter j

studies.

The research should assemble and assess data produced by previous experiments prior to initiating new leaching experiments, as needed.

The

{

research should combine field lysimeter and laboratory data into a comprehensive data base to su Once validated, the release model(pport validation of the release model.

s) should be further tested by attempting to simulate measured radionuclide concentrations observed in trench leachates at existing LLW disposal f acilities.

2.

Ef fects of Chelating Agents and Other Constituents on Decontamination Waste Releases (Priority A)

Research is needed to assess the effects of chelating agents and other non-radiological constituents on the release and transport of radionuclides from decontamination wastes. Research should include testing of radiation degradation effects, assessment of complexing interactions with other wastes, long-term leach tests to characterize the release mechanisms, biodegradation effects, and effects of oxidizing chemicals on ion-exchange resins. The research should be integrated with assessments of radionuclide tran!. port to verify that chelation and/or complexation of decontaufnation wastes would not compromise performance of disposal sites.

3.

Screening Tests for LLW form and Container Stability (Priority A)

Research is needed to examine the screening tests and test procedures that are identified in NRC's Technical Position on Waste form (february 1983) to determine if other tests, test methods, or testing criteria are mere effective in evaluating long-term physical properties of current LLW forms and container materials. NRC's Technical Position on Waste form recommends testtog procedures to be used by generators in demonstrating that their LLW forms and container materials meet the 300-year stability requirement in 10 CFR part 61.

New information has indicated, however, that LLW forms and container materials that satisfy NRC's Technical Position do not actually perform as well as expected. Therefore, NRC needs research to evaluate whether other tests and/or testing criteria provide results that are more representative of the long-term performance of the LLW forms and container materials. The research should provide specific reconnendations about the need for revising the tests, methods, or criteria in NRC's Technical Position on Waste form and, if appropriate, identify suitable alternatives that provide greater assurance that LLW fonns and container materials will remain structurally stable for at least 300 years.

4 Infiltration Evaluation Methodology for low-tevel Waste Disposal facilities (Priority A)

Research is needed to develop evaluation techniques and procedures f or reviewing earthen and other engineered subsurf ace drainage control systems designed to minimize infiltrat ion at llW disposal facilit ies.

The methodology NUltl!G-1380

^4

n 1

\\

shculd be flexible enough to consider external perturbations such as the 1

effects of vegetative development and wetting-drying cycles.

The methodology should also provide sufficient flexibility to assess downward, lateral, and upward movement of water into waste material for cover designs consisting of carthen materials, geomembranes, or concrete barriers. The research should develop specific procedures for analyzing cover designs using existing analytical and numerical. codes and available data from field-scale testing.

The research should also develop acceptance and review criteria for determining then design features would adversely affect or enhance site hydrogeologic c:nditions with respect to waste isolation. Research products should include (1) an analysis that identifies processes that significantly affect c:nditions to minimize infiltration 'through covers, (2)ptimum hydraulic infiltration through cover systems and that describes o an evaluation of the capabilities and limitations of existing analytical and numerical techniques fcr assessing infiltration through cover systems, and (3) an integrated analytical framework, including computer codes, for reviewing the design performance of cover systems.

5.

Archival Trench Program (Priority A)

Pescarch is needed to develop an archival trench test program.and protocol to c nfirm the long-term performance of LLW forms and container materials. Each archival trench should cor.tain actual LLW, HIC container materials, and HIC's etntaining LLW. Periodic evaluation of actual waste and container samples directly supports NRC staff licensing reviews and assessments of the validity and representativeness of extrapolating short-term testing results to represent long-term performance of LLW forms and containers.

In' addition, evaluation of actual sample performance could be used by NRC staff to identify significant new technical issues that need to be resolved to ensure safe operation of LLW

{

disposal facilities. The research should construct the trenches and p:riodically remove, examine, and test samples of LLW, HIC materials, and HIC's c:ntaining LLW. The surveillance aeriod for these samples should be planned for a 50-year period. The researci should recommend testing methods for l

rstrieved samples (emphasizing visual inspection), conduct the sampling and examination,-assess sampling results, and provide NRC with recommended l

rsvisions to waste form guidance and requirements.

l 6._

Long-Tenn Performance of Concrete Structures (Priority A) i R search is needed to evaluate environmental and chemical effects on the durability of concrete, rebar, and joint sealing materials to ensure acceptable I

parformance of these materials as major components in LLW disposal facilities.

C;ncrete and associated materials (i.e., rebar and structural joint materials) must be durable to ensure long-tenn integrity and serviceability of important concrete structures at LLW disposal facilities.

In the case of joint materials, both the properties and function of the joint naterials must be durable to provide reasonable assurance of adequate radionuclide containment.

The research should place special emphasis on the effects of aging and environmental conditions (e.g., weathering, terrperature variations, l

NUREG-1380 A-9

i i

biodegradation, and groundwater interactions) on the service life of concrete and related materials. Research products should include recommended design and review criteria for concrete structures used in LLW disposal facilities.

7.

Covers and Liners (Priority B)

Research is needed to evaluate current techniques used to verify as-built characteristics of earthen liners and covers to ensure satisfactory performance of these engineered barriers at LLW disposal facilities. The research should include a comparison of construction parameters and characterization techniques applicable to engineered earthen barriers. The research should also include a comparison of laboratory versus field characterization methods for determination of hydraulic parameters such as permeability. This research should be integrated with the development of a methodology for estimating long-term infiltration rates through earthen cover systems. The research should also identify and investigate methods to verify the long-term performance characteristics of cover and liner systems that use capillary barriers considering the life of geotextiles, migration of fine-grained soils into coarser underlying layers, and long-term mintenance requirements.

Research results should be jirovided in a suitable manner for incorporation in technical guidance or standard review procedures.

8.

Development of Erosion Protection Design Criteria for Long-Term Stabilization"(Priority B)

Research is n(eded to develop erosion protection design criteria for long-term stabilization and information about the magnitudes, rates, and impacts of erosion processes on long-term stability of earthen cover systems. Such criteria and information are required for NRC to license and approve facility designs and develop regulatory guidance regarding crosion protection.

HMSS has sponsored hydraulic flume studies at the Colorado State university during the last several years to enhance NRC's regulatory basis for approving erosion protection designs. Additional flume testing is needed to expand the existing data base and develop specific analytical procedures for reviewing erosion protection designs. Products from the additional flume testing would include testing data from fiume testing using soil covers, analysis of these data, design criteria for riprap erosion protection and soil covers, design criteria for rock durability, and detailed design review procedures relevant to long-term stabilization reviews of LLW disposal facilities.

9.

Load Deformation Characterization and Modeling (Priority B)

Research is needed to (1) characterize the load-deformation response of various components of a low-level Waste Disposal facility (LLWDF), including LLW, backfill surrounding waste, structural components of disposal units, and multi-layered covers; and (?) model the long-term settlement and subsidence of l

a LLWDT.

As part of the review of a license application, the staff will l

evaluate the long-term settlement and subsidence of a proposed LLWDf.

NUltilG-1380 A-10 l

Settlement and subsidence will be a curnulative response of the LLWDT components listed above and ruoy adversely affect the performance of snulti-layered cover systems consisting of various layers of soil, gravel, geotextile filter, geotextile reinforcing mat, riprap, concrete dolos, and concrete structures.

Short-and long-term degradation of heterogeneous wastes coupled with infilling and gradual consolidation and settlement may disrupt the layers of the cover systems, thus degrading their ability to minimize infiltration and control gaseous releases. The research should develop an analytical framework, including supporting computer codes, to assess load-deformation response of alternative placernent configurations of waste, backfill, and disposal unit structures, as well as the analytical tools required to assess long-term settlement of such heterogeneous systems. The research should consider alternative waste forms (e.g., bitumen) that may significantly influence settlement / subsidence and alternative methods of LLW disposal. The research should also provide specific recommendations about typical values and ran s of parameters to be used in settlement evaluations.

In addition, the research should provide reports to LLWM that (1) compile information about settlement at existing LLWDF's; (2) ident,ify design, construction, operation, and closure features that significantly affect cover settlement; and (3) recorsnend acceptance and rcview criteria for NRC staff reviews of settlement evaluations in support of LLWDF license applications.

C.

SITE CHARACTERIZATION AND MONITORING 1.

Unsaturated Zone Monitoring (Priority A)

Research is needed to identify and assess alternative techniques for inonitoring moisture covement and contaminant transport in the unsaturated zone at LLW disposal facilities. NRC's regulations in 10 CFR Part 61.53 require that environmental monitoring systerns provide early warning of radionuclide l

releases. Unsaturated zone nonitoring may be capable of providing such early warning of releases.

In addition, such inonitoring may be needed to verify performance assessment results used to demonstrate compliance with the performance objectives in Part 61. Research should especially focus on t

techniques applicable in low moisture (arid) environments, the long-term durability of unsaturated zone monitoring systems, and assessment of monitoring p(arameters as indicators of facility performance.1) an assessment of the capa The research should provide for monitoring moisture tovement and contaminant transport in the unsaturated zone, (2) recormnended techniques for unsaturated zone monitoring at LLW i

disposal facilities, (3) guidance on the design, installation, use, maintenance, and decomissioning of unsaturated zone monitoring systems, and (4) an evaluation of the extent to which unsaturated zone monitoring systems snay compromise the performance of natural and engineered barriers at LLW disposal facilities and reconrnendations on how to eliminate or mitigate such compromises.

1 1

A.11 NURiiG-1380 1

i 2.

Hatural Landform Modifications (Priority B)

Research is needed to assess the types and rates of natural landform modifications that should be considered in evaluating geologic stability of LLW disposal facilities. Geomorphic processes may significantly affect a site's long-term stability. Because many of these processes are slow and occur episodically, they are frequently not detected in typical site characterization programs. The research should consist of literaturc reviews and field testing of old and new characterization methods.

The research should develop a methodology consisting of a set of alternative techniques to assess the types and rates of geomorphic processes that may significantly affect the stability of LLW disposal sites based on analysis of landform modification. The methodology should be flexible enough to account for variables such as climate, lithology, vegetation, and time, in addition, the research should provide specific recommendations of the use of new or existing methods and instruments for monitoring gradual geomorphic processes necessary for assessing the long-term stability of LLW disposal facilities. The methods and instruments should be practical tools f,or measuring, calculating, and modeling such processes as long-term soil erosion, hillslope evolution, and gully and channel incision.

D.

PERFORMANCE ASSESSMENT 1.

Performance Assessment Scenario Evaluation (Priority A)

Research is needed to evaluate the relative significance of various exposure scenarios and radionuclide transport pathways to identify critical data and assessments that have the most influence on demonstrations of compliance with the performance objectives in 10 CFR Parts 61.41 and 61.42.

This research should be integrated with development of a LLW performance assessment methodology by NMSS to support selection and analysis of alternative models and computational tools for performance assessment. The research should also develop codes and models, as necessary, to implement the LLW performance assessment methodology and demonstrate application of the methodology for representative LLW disposal facilities.

2.

Transport Behavior of' Carbon-14 and Tritium (Priority A)

Research is needed to improve NRC's ability to predict the migration behavior of carbon-14 and tritium from LLW disposal facilities.

Existing assumptions about their migration behavior, as described in Regulatory Guide 1.109, are apparently orders of magnitude too conservative. The research should assess the following items: the partitioning of C-14 and H-3 between air and groundwater pathwayst the rate of their migration in air and groundwater; and the extent to which they can be taken up by plants.

The research should characterize the release and subsequent transport behavior of C-14 and H-3 and provide LLWM with information that may be used to review and confirm assessments of radionuclide transport in support of license applications.

The NURIiG-1380 A-12

research should provide (1) a report dercribing the details, conclusions, and regulatory implications of the assessmeit, (2) ranges of attenuation parameters for C-14 and H-3 over the range of geochemical conditions expected at potential LLW disposal sites, (3) ranges of plant uptake factors for C-14 and H-3, and (4) analytical functions describing the release of C-14 and H-3 from representative LLW forms that can be used as source terms for grcundwater and atmospheric transport models.

3.

Geochemical Transport of Contaminants at LLW Disposal Sites (Priority B) 7 Research is needed to collect and develop infonnation to validate and use computer models to predict the transport and reaction behavior of contaminants in groundwater at LLW disposal sites. The research should provide a method for assessing the effectiveness of alternative corrective actions for contaminated groundwater at the sites. NRC must understand contaminant transport behavior sufficiently to license LLW disposal facilities, approve environmental monitoring plans, and provide guidance about characterizing and predicting contaminant mobility and transport. This research should provide NRC with information about the effects of changes in geochemical conditions on contaminant transport, ranges of attenuation factors for radionuclide migration, effectiveness of corrective actions for contaminated groundwater, and selection of indicator parameters that may be used to assess the general geochemical characteristics that significantly influence contaminant release and transport from LLW disposal facilities. This information will be used by NRC staff to validate, use, and review computational models to predict contaminant transport at mill tailings disposal sites.

In addition, the research should provide acceptance and review criteria for geochemical characterization and assessment at LLW disposal sites.

E.

DECOMMISSIONING 1.

Assessment of Technology, Safety, and Costs of Decomissioning Power Reactors (Priority A)

Research is needed to update NUREG reports on the technology, safety and costs of decomissioning power reactors to reflect changes in policy and technology based on financial assurance considerations required in the Decontamination and Decomissioning rule, revised cost estimates based on decomissioning experience, and technological improvements. These reports were originally prepared for NRC in the 1970's by Pacific Northwest Laboratories. Research is also needed to collect and assess reactor decomissioning information on technology, task manpower requirements, and waste disposal to review l

assessments of decomissioning costs and waste disposal needs.

In particular, I

research is needed to continue collection and assessment of information from decomissioning projects at Shippingport and Lacrosse.

The research should provide revised reports based on current information.

These reports will provide information to be used in reviewing licensee decommissioning plans and i

financial assurance cost estimates.

l l

A-13 NUREG-1380 1

2.

Assessment of Technology, Safety and Cost of Decomissioning Non-Reactor Nuclear facilities (Priority A)

Research is needed to update NUREG reports on the technology, safety and costs of decomissioning non-reactor f acilities to reflect changes in policy and technology based on financial assurance considerations required in the Decontamination and Occomissioning rule, revised cost estimates based on decomissioning experience, and technological improvements.

The original reports were prepared for NRC in the 1970's by Pacific Northwest Laboratories.

Research is also needed to collect and assess non-reactor decomissioning information on technulogy, task manpower requirements, and waste disposal as input for assessments of decomissioning costs and waste disposal needs.

The research should provide revised reports based on current information. These reports will provide information to support reviews of licensee decomissioning plans and financial assurance cost estimates.

3.

Capabilities of On-Site Reactor Radwaste Systems to Process Decomissioning Wastes (Priority B)

Research is needed to identify potential decontamination processes and to characterize their wastes. Decomissioning operations may use chemical decontamination methods that could produce wastes that differ substantially from those wastes normally processed in reactor radwaste systems. The research should assess the adequacy of conventional radwaste processing systems, including ion-exchange, filtration, evaporation and solidification methods, to ensure that they will be capable of stabilizing wastes containing the decomissioning wastes in compliance with 10 CFR Part 61 and Agreement State requirements. The product of this research should be a report which identifies potential processing difficulties and safety concerns with respect to both systems operations and waste disposal. This information will be used reviewing licensee decomissioning plans to ensure that wastes projected from decommissioning operations can be properly processed to produce waste forms suitable for disposal.

NURiiG-1380 A-14

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a APPENDIX B DETAILED DISCUSSION OF STRATEGY

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CONTENTS OF APPENDIX B i

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1 B.1 Waste Form and Other Material Concerns................................................

B-5 B.1.1 Wast e Characterization.........................................................

B-5 i

B.1.2 Testing Methods to Ensure Regulatory Compliance..................................

B-7 11.1.3 D ecommission ing...............................................................

B-10 11.2 Failure Mechanisms and Radionuclide Releases............................................

B-10 B.2.1 Wast e Form Performance.......................................................

B-10 B.2.2 Radion uclid e R el easec..........................................................

B-14 11.3 Engineered llarrier Performance........................................................

B-15 11.3.1 Long-Term Performance of Iligh. Integrity Containers...............................

B-15 B.3.2 Long-Term Concret e Performance................................................

B-17 11.3.3 leng-Term Cover Performance...................................................

11-1 9 11.4 Site Characterization and Monitoring.....................................................

B-21 11.4.1 Sit e Charact e rization............................................................

B-21 B.4.2 ' M o n it o ring....................................................................

B-24 11.5 Pe rformance Asse ssm e n t...............................................................

B-26 11.5.1 Performance Assessment Pathway Model Evaluations................................

B-26 11.5.2 So u rce Te rm..................................................................

B-28 11.5,3 Transport of Radionuclides and Chemicals at 11W Disposal Sites.....................

B-30 FIGURES 11.1 Research strategy for Waste Form and Other Material Concerns program element..............

B-6 11.2 Research strategy for Failure Mechanisms and Radionuclide Releases program element..........

11 - 1 1 11.3 Research strategy for Engineered Barrier Performance program element.......................

B-16 11.4 Research strategy for Site Characterization and Monitoring program element...................

B-22

-11.5 Research strategy for Performance Assessment program element.............................

B-27 i-B-3 NURiiG-1380

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'IM appendix contains an elaboration of the strategy and chemical analysis of LIAV streams is particularly impor-integration for meeting the program goals discussed in tant for assessing the stability of solidified waste forms, Chapter 4 and includes discussions of the regulatory ap-where chemical components in the waste streams either plication of the research, relationships between research accelerate or retard the setting of ecment and thereby areas, and products and milestones.

cause formsjo fait.

H.1 Waste Form and Other Material Research Strategy to Meet Program Goal Concerns

'Ihe overall strategy for characterizing LLW will be to (Fig.11.1 illustrates the research strategy for addressing perform radiological, chemical, and biological analyses of this program element.)

actual samples of waste streams and solidified waste forms collected from operating nuclear power plants. For solidified waste forms, both small and f ull scale samples H 1.1 Waste Characten,zation will be collected. Top priority will be given to analysis of decontamination waste streams and activated metals. To Program Goals meet the program goal, the following need to be done:

'the primary goal in this research area is to characterize e

low. Level Radioactive Waste Streams 1.LW streams of nuclear facilities, other generators of LIAV, and solidified waste forms for short and long-lived 1.

Characterize all major radwaste streams from oper-radionuclides, chelating agents, and chemical and biologi-ating nuclerr power plants for physical properties cal pontent to meet the LIAV waste classification and and for radionuclide and chemical content prior to waste form characterization and stability requirements of solidification in cement or bitumen. Characteriza-

- 10 CFR Part 61 and the NRC branch technical positions tion should include an analysis of ion exchange res-on radioactive waste classification, waste form, and stabil-ins expected to be solidified in ecment and chelating ity,'lhe purpose of obtaining these data is to provide agent content for decontamination waste streams.

NRC with guidance on LLW characterization and waste form stability and to determine realistic radionuclide re-2.

Determine the distribution of long-lived radionu-lease data for use in modeling radionuclide and chemical clides in LLW and decommissioning reactor compo-tr:nsport from 11W disposal sites.

nents by conducting (a) an analysis of low !cvel wastes and decommissioning waste samples to deter-B ~ ckground mine the significance of selected long lived radionuclides (e.g., Mo-93, Ag-108m, Mn-54, Accurate characterization of the waste stream is funda-Ni-63, Cl-36) other than those listed in 10 CFR mental to any effort to ensure the safe disposal of L13V.

6 61.55;(b)an assessment of the adequacy of exist-There is some uncertainty about the radionuclide content ing radiochemical and analytical techniques (e.g.,

of actual LIAV streams and how they will meet 10 CFR dispersion, bias, repeatability, sensitivity) with em-Part 61 waste classification requirements. The complex phasis on radionuclides such as 1-129, Ni-59 and mix of radiological and chemical components of LI AV die.

Ni-63, and Nb-95 and Nb-95m;(c) an assessment of tates how it will interact with the waste form and contain-the quantities and potential significance of radionu-ers and ultimately whether hazardous substances will be clides such as 1-129 and Tc-99; (d) an assessment of moved into the environment in order to predict er radionuclides and daughter products, (c) an assess-source term for dose calculations at 11% disposal facili-ment of generic scaling factors for use when sample ties, data and information are needed on the radiological, results are below the lower limit of detectiont (f)an chemical, and biological composition of LLW streams and evaluation of the adequacy of existing dose to-curie l

solidified LLW forms generated by nuclear facilities and measurement techniques; and (g) an assessment of other LIAV generators to evaluate the distribution and other radionuclides that may be present but may potential movement of those components. Many radionu-have been overlooked by normal radiological analy-clides are difficult to observe and normally are not in-sis, Emphasis will be placed on "hard-to analyre l

cluded in routine LI AV analysis programs and may not be radionuclides" (non gamma ray emitting radionu.

listed in Tables 1 and 20f part 61.These include beta-and clides) and those requiring complex radiochemical i

alpha partic)e-emitting radionuclides and transuranics as separation.

well as many radionuclides present in LI AV decontamina-tion waste where complex radiochemical methods are Solidified LLW used in tht decontamination process. Furthermore, chelating agents present in decontamination waste are 1.

Collect cement-solidified decontamination, evapo-gcnerally no measured. The detailed radiological and rator, and other LLW from operating nuclear power 11-5 NUREG-1380

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E WASTE FORM & OTHER MATERIAL CONCERNS STRATEGY NT l

WASTE DECOMMISSIONING CHARACTERIZAW WASTE PROCEDURES M

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RADIOLOGICAU CHEMICAL

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PROPERTIES DECONTAMINATION PROCESS CONTPOL PARAMETERS WASTES OTHER WASTE MIXED RADWASTE QUANTmES WASTE ALT. LLW ACTIVATED TREATMENT l

METALS COST l

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MIXED TESTING WASTES Figure B.1 Research strategy for Waste Form and Other Material Concerns program element.

plants, and characterize solidified decontamination '

can be compared with licensee data obtained in LLW and ion-exchange resins for radionuclide, process control programs for solidified waste forms.

chelating agent, and chemical content. Emphasire the analysis of solidified 11W containing sulphate 7.

Evaluate testing methods proposed in NitC branch regenerated ion exchange waste from IlWits, boric technical positions on 11W classification and stabil-acid concentrates from PWIts, and decontamination ity and the proposed draft regulatory guide on LLW waste using CAN DECON, LOMI, and other form stability -

chemical processes for radionuclide and chemical contems.

Integration and Relationship to Other Research

' 2.

Collect bitumen solidified LLW samplcs from oper-ating nuclear power plants, and perform laboratory Characterizing LLW streams and waste forms will help -

analyses to determine radionuclide, chemical, and NitC to evaluate:

chelating agent concentration.

1.

"Ihc potential for teaching of radionuclides and chelating agents from solidified decontamination Regulatory Applications waste forms:

11W must meet the waste classification and waste form 2.

'lhe potential for lear..amg of radionuclide and characterization and stability requirements of 10 CFil Part 61. Research is necessary to chameteri7e 11W and chemical compounds from cement solidified waste forms; classify the distribution of long-lived radionuclides in waste streams and solidified waste forms to determine if 3,

.lhe effects of chelatin8 88ents on radionuclide these provisions have been met.*lhe research effort will transpor4 provide information that ctm be used by the staff as a basis for regulatory decisions on topical reports as well as modi-4.

Itcalistic radionuclide, chemical, and chelating fications to the NitC branch techrucal positions on radio-agent source terms, transport, pathways analysis, active waste classification and waste form, the proposed uptake, transfer coefficients, and dose estimates:-

draft regulatory guide on LLW form stability, and llegu-latory Guide 1.21 or for a potential rulemaking in thesc 5.

Methods for retarding or enhancing cement solidifi-areas of LLW waste management. Specifically this re-cation and search is needed to:

6.

"Ihe field performance of certified topical report for-1 Support development of regulatory criteria for en.

mutations, suring classification and characterization of LLW and stability of cement solidified 11W in accor-I*roducts and Milestones dance with 10 CFR Part 61 requirements.

(All work to be performed by INEl. FIN A6359.)

2.

Provide data on leachability of radionuclides, chelat-ing agents, and chemicals from solidified waste 1.

Complete collection of radwaste stream and solidi-forms that will provide a technical basis for a draft ficd radwaste from operating nuclear stations, FY regulatory guide on low level waste form stability, g99 g, 3J Provide data for making licensing decisions and pro-2.

Complete analysis of 11W and solidified waste for viding guidance on radionuclide and chelating agent radionuclide, chelating agents.andchemicals,FYs releases from 11W.

3991 1993.

4.

Provide data for making licensing decisions and pro-3.

Complete analysis and prepare report on results of vidmg guidance on ion exchange resins contammg analyses. FY 1993.

radionuclides and chelates released and solidified in

"" * * "I' H.1.2 Testing. Methods to Ensure Regulatory 5.

Provide radionuclide release data for radionuclides Compliance and chelating agents for use in transport of radionu-clides from low-level waste burial sites.

Program Goals 6.

Provide independent basis for cvaluating licensce's

'the primary goals for testing methods research arc (1) to

'L' decontamination and characterization data and identify, evaluate, and recommend suitable test methods analyses. 'the results of NRC sponsored research for measuring critical parameters to ensure that the 11-7 NUREG-1380

E performance of solidified waste fo:Tns is within specified waste. Tests using actual solidified LLW from nuclear limits; (2) to identify, develop, and recommend safe, reli-power plants are usually not performed due to the costs ab!c, and econom: cal test methods for inspection of LLW involved, radioactivity content, and ALARA concerns.

t received at 11W disposal facilities; and (3) to develop Data from studies performed on actual small and full-new test methods as appropriate or recommend existing scale solidified 11W and activated metals are needed to methods to assess and confirm important LLW character-establish stability criteria.

htics in receipt inspection. Several subgoals include (1) ensuring that solidified waste forms containing LLW Current inspections of solidified 11W forms at existing meet the stability requirements of 10 CFR Part 61 by burial sites verify compliance only with the free liquid and identifying critical process control parameters for suc.

solidification requirements of 10 CFR $ 61.56 and may cessful solidification and by determining performance not detect inadequately solidified waste. Information on specifications for 11W solidified in cement, bitumen, additional testing is needed to identify reliable, safe, and vinylester stryene, and other solidification media; economical test methods for receipt inspections of LLW (2) evaluating the structural stability of actual solidified to verify compliance with 10 CFR 9 61.80 and other LLW LLW generated at operating nuclear power plants by disposal site waste form requirements.

evaluating the test methods in the NRC branch technical position on LLW waste form and the proposed draft regu, Research Strategy to Meet Program Goals latory guide on LLW stability;(3) examining the test pro-Waste I.orm Stability cedures recommended in NRC's technical position on waste form and the proposed draft regulatory guide on 1.

Review existing tests and performance standards in waste form stability to determine if these tests or other tests are more effectise in evaluating long term proper-NRC's branch technical position on waste form sta-ties of 11W forms; and (4) cvaluating the need for revis-bilitI*

ing specific tests or criteria on waste forms and identify-2.

Propose, develop, and evaluate new tests as needed ing, as needed, alternatives that provide assurance that for assessing long term performance of stabilized solidified waste forms will terr.ain structurally stable for waste forms and container materials.

300 years.

3.

Review cement formulations to determine the need for development of more stable and long-lasting cc.

Background

ment waste forms as needed (experimental and 10 CFR Part 61 requires LLW forms to be structurally stabic. The NRC's branch technical position on waste 4.

Collect actual solidified 11W samples from nuclear form specifies screening tests, test procedures, and per-power plants and other LLW generators, and per-formance characteristics for ensuring that waste forms, form NRC's branch technical position tests on them especially radwaste solidified in cement, meet the to determine their stability Determinc LLW ehemi-300-year rtructural stability requirements of Part 61.

cal and physical composition (see Section B.I.1,

" Waste Characterization," and Section B.2.1,

. Recent studies using actual cement solidified decontami-

" Waste Form Performance").

nation and ion-exchange resin LLW from nuclear power plants have shown complete deterioration upon immer.

5.

Study physical chemistry processes involved with ad-sion in water. In addition, several nuclear power plants mixture effects of LLW by assessing the chemical experienced situations involving unsuccessful 11W so.

and physical properties of LLW cffects on retarding lidification, bulged liners, and incomplete mixing of de.

or enhancing the setting up oflicensecs'ccment for-contamination 11W in cement because of too rapid cc.

mutation. Develop chemical thermodynamic and ment solidification. In two studies involving leaching of kinetic model for predicting cement set-up and radioactive materials from cement solidified BWR properties, using ILW composition and cement for-evaporator wastes, deep cracks and spalling occurred in mutations for solidification of evaporator and decon-the waste forms. These results, along with information tamination LLW.

from several licensee process control programs, suggest 6.

Perform literature studies to assess existing data on that LL% forms satisfymg NRC s techmcal position on waste form stability may not perform as expected when bitumen solidification of LLW, and evaluate testing actual wastes from nuclear power plants are myolved.

procedures of bitumen-solidified waste form

7.

Identify elements of a quality c(mtrol program that Performance tests and criteria specified in NRC's branch will ensure that weste form stability is achieved.

technical position and proposed draft regulatory guide on waste form stability have been determined from studies 8.

Determine effects of pil control on formation of using small laboratory samples containing simulated gellike material formed when lime is added to NUREG-1380 B-8

ion-exchange resins containing picolinic acid in the waste form and the proposed draft regulatory guide on LOMI decontamination process prior to solidifica-waste form stability and to develop the elements of a tion in cement.

process control program for ensuring successful dewater-ing and solidification of 11W.The assessment and confir-9.

Examine bulged lincts containing solidified decon-mation of LLW characteristics in receipt inspections at tamination waste from nuclear power plants to de-burial facilities would be greatly enhanced with the re-termine causes for expansion.

sults of these research studies.

10. Examine unsuccessful decontamination solidifica-Integration and Relationship to Other Work tions of 11W m liners that occurred at nuclear power plants, and determine causes for the un-

'Ihis work is related to research associated with waste solidification in cement, characterization (see Section 11.1.1), waste form and package performance (see Section 11.2.1), effects of

11. Evaluate and publish report on case histories of re-chelating agents on decontamination releases (see Sec-cent ecment solidification problems involving 11W tion 11.2.1), chemical, radioactive, and biologic effects on at operating nuclear stations (lessons learned Re-the degradation of solidified 11W and container materi-port). Include information from laboratory studies als, and radionuclide release determinations (see Sec-reporting degradation of decontamination 11W cc-tions B.2.2 and 11.5.3), and performance assessments (see ment samples collected from operating nuclear Section II.5) of 11W burial facilities, power plants and leached in demineralized water and water of varying pH levels.

I'roducts and Milestones O

Process Control Program (All work to be performed by INEL FIN A6359.)

Review and evaluate existing proecss c(mtrol program 1.

Complete examination and assessment of actual un-pl:ns. Evaluate licensecs' technical and administrative successful cement solidification at power stations, procedures for solidifying 11W.

and prepare case history report documenting solidi-fication problems at nuclear stations, FY 1990.

o Waste Receipt inspections 2.

Complete review of existing process control pro-1.

Assess, develop, and evaluate test methods for waste gram requirements, technical position methodology receipt inspections at LLW disposal facilities.

and tests, and waste receipt test methods, FY 1991.

3.

Complete collection of ccment solidified LLW from 2.

Evaluate the utility of the following in situ testing actual nuclear power stations, FY 1990, methods for solidified waste to ensure solidification d

at burial facilities:

4.

Complete testing of actual solidified LLW using waste form stability tests in NRC branch technical a.

Sonar tests position paper on waste form stability, FY 1991, b.

X rays 5.

Complete determination of waste characterization c.

" Hammer" tests / taps 6.

Complete assessment of the need for new tests, and, d.

Magnetic resonance if needed, propose new tests to determine stability of waste forms, FY 1992.

c.

Infrared 7.

Complete evaluation for new process control pro-f.

Gamma ray scanning of liners / drums gram guidelines and, if needed, propose new guide-lines, FY 1992.

Regulatory Applications 8.

Begin assessment of the need for new cement and g[ff "3 399i"

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8 Research results from this investigation would be used by fg the NRC staff to review performance of licensee and ven-dor formulations for 11W solidification and for develop-9.

Complete study to determine admixture effects of ing technical positions on LLW waste form stability to 11W cement interactions, FY 1993.

mcet 10 CFR Part 61 requirements. Test methods and pcrformance criteria developed from the research would

10. Begin study to develop chemical models for predict-be used to revise NRC's branch technical position on ing cement set-up time, FY 1993.

B-9 NUREG-1380

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11. Complete development of quality control program view of the technology, safety, and costs of decommission-for LLW form stability, FY 1991.

ing all nuclear facilities with special emphasis on power reactors.

12. Complete review, evaluate, and propose test meth-ods for process control program and waste receipt inspection program, FY 1992.

Regulatory Applications The research effort under way is to provide informy. ion 11.1.3 Decommissioning for directly implementing the decommissioning rule amendments to 10 CFil Parts 30, 40, 50, 70, and 72.

Program Goals Moreover, information on radioactive waste detection and characterization obtained by PNL under FIN B2880 The primary goal in this research area is to develop infor-will also be used to implement 11W rule requirements of mation for implementing the recently issued decommis-10 CFR Part 61.

sioning rule amendments.

Integration and Relationship to Other Ilackground Research The NRC recent!y issued decommissioning rule amend-Information resulting from this tescarch has been coordi-ments to 10 CFR Parts 30,40,50,51,70, and 72 which, nated with efforts on plant aging, life extension, and LLW aside from financial assurance requirements, emphasize

disposal, early planning and deta iled final plans for completing de-commissioning so that nuclear facilities cim be available for unrestricted use and the NRC license terminated.

Products and Milestones Decommissioning information, especially for large power 1.

Characterization of radioactivity resulting from de-reactors,is scarce, and most of the information generated commissioning as a source term and as a generator in support of the decommissioning rule amendments was for waste disposal; progress report FY 1990, final based on the decommissioning and decontamination of report FY 1992.

small facilities. Such information, together with other technical data, was used to generate a series of reports on 2.

Humboldt Bay decommissioning activities (FY the technology, safety, and costs of decommissioning nu-1990), Shippingport decommissioning activities-clear facilities. limphasis on acquiring more information tasks and efforts required to be completed FY 1992.

on acttial decommissionings has driven and continues to drive the current research effort.

3.

Complete assessments of technology, safety, and costs for nuclear facilities, FY 1993.

Research Strategy to Meet Program Goal IES continues to generate and collect information that B.2 Failure Mechanisms and will be useful to NMSS in its licensing decisions concern.

Radionuclide Releases ing LLW from decommissioning. Pacific Northwest I abo.

ratories (PNL) are investigating the radiological and (Fig. B.2 illustrates the research strategy for addressing chemical chameteristics of decommissioning waste from this program element.)

nuclear power stations. In particular, many samples have been taken from the Shippingport reactor to characterize 11.2.1 Waste Form Performance the distribution, curic quantity, and isotopes remaining prior to dismantlement and decontamination as well as the type and quantities of radioactive decommissioning Program Goals waste.

The primary goals are (1) to obtain data and information Westinghouse has been documenting actual decommis-necessary to provide guidance on the stability of solidified sioning activity efforts in terms of tasks and mmpower ef.

LLW forms, and (2) to determine realistic radionuclide, forts for various reactors such as ilumboldt Bay and Ship-chelating agent, and chemical release data from LLW fa-pingport to obtain estimates of unit costs for various cilities for use in assessing their impact and for modeling decommissioning activities.

these releases in the environment. Specific goals under the investigation of waste form performance are (1) to de-PNL is assessing all decommissioning information ac-termine the leaching of radionuclides, chelating agents, quired (such as at Shippingport) to present a current over-and chemicals from actual solidified LLW, especially NUIEG-1380 D-10

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FAlWRE MECHANISMS & RADIONUCUDE RELEASES STRATEGY 7

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3 Figure B.2 Research strategy for Failure Mechanisms and Radionuclide Releases prtgram element.

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decontamination 11W solidified in cement, and activated waste releasest (3) the effect of radiation and biodegra,la-metals from nuclear power stations, (2) to determine the tion on solidified 11Wt and (4) the leachability of acti-cffects of chelating agents on enhancing the migration of vated metals.

radionuclides from 11W sites, and (3) to determine chemical, radiological, and biological effects on the stabil-To meet the program goals, the following research should ity of 11W forms, be done Research studies should be performed on actual materials such as solidified (e.g., cement) 11W samples, activated metals, chelating agents, etc., collected from

Background

nuclear power plants. Small-and full scale solidified waste forms of cement solidified decontamination, 10 CFR Part 61 requires that radionuclide release, chelat-napmatm, and omu W streammH k innsdgand.

ing agent concerns, and the stability of 11W forms be ad-All tests recommended in the NRC s branch technical po-dressed in evaluating the performance of 11W burial fa-cilitics. Part 61 further requires that the structural n on wasm orm and the proposed regulatory guide m 1.

wasm onn stability will be performed. lxachmg stability of11W forms be evaluated against chemical, ra-studies wdl use demmeralized water, sea water, and ac-diation, and microbial effects.The NRC branch technical tual gr und water from selected environments and at position on waste form and the proposed draft regulatory guide on 11W waste form stability require that all waste

""""E" 8'

forms, especially solidified waste forms, be tested for Radiation studies should be performed using internal and chemical, radiation, and microbial effects and evaluated mixed-field radiation from actual waste forms containing against critcria detcrmmed from laboratory samples usmg radioactive materials at low dose rates (102-10) rads /hr simulated waste and not actual solidified radwaste.

and up to a total dose of 10e rads).

Leachability of radionuclides and chelating agents from o

Stability /Leachability of Solidified 11W solidified waste forms and compressive strength tests of solidified 11W forms are factors in determining ILW l.

Conduct small and full scale tests on cement.

form stability and in evaluating radionuclide releases solidified waste forms from operating nuclear power from 11W facilities. Current teach rate data for plants containing decontamination and evaporator radionuclides are based on small laboratory samples using concentrates according to 10 CFR Part 61 waste simulated waste streams and may not be realistic-form stability requirements using the methods speci-fied in the NRC branch technical position on waste Leaching data and information on radionuclides, chemi-form and the proposed draft regulatory guide on cats, and chelates released from actual reactor solidified waste form stability, decontamination wastes are not readily available except from a few studies of cement solidified decontamination 2.

Perform compression testing of solidified waste wastes and evaporator concentrates from several operat.

forms collected from operating nuc! car power plants j

ing IlWRs lthese are currently under way at INEL (FIN before and after Icaching and over time to deter-A6359)). These studies use small laboratory samples and rnine effects of curing on compressive strength and short termleachingteststodetermine releases.Dataand Icachability of radionuclides and chemicals from cc-information from long term leaching of actual full sized ment waste forms.

solidified radwaste forms are needed to confirm the re-sults of this work.

3.

Determine effects of varying waste /ccment ratios on leaching of radionuclides and chelating agents.

The increased use of decontamination processes by the nuclear industry is generating LLW containing various 4.

Study short and long-term leaching of radionu-chelating agents and radioactive materials. The releases clides, chelating agents, and chemicals from solidt-of chelating agents from actual solidified 11W is not well fied decontamination, evaporator, and other 11W characterized, and their impact on the release and trans.

from operating nuclear power plants.

port of radionuclides from the solidified waste forms must 5.

Determine short-and long-term leaching mecha-be determined for accurate performance assessment' nisms for radionuclides and chemicals leached from solidified waste forms immersed in demineralized Research Program Strategy to Meet Program water, sea water, ground water, and water at various Goal PH levels.

The strategy for resolving waste performance uncertain-6.

Perform lysimeter studies in arid and humid climates ties is divided into four parts: (1) the stability /leachability using decontamination waste and evapontor wastc of solidified waste forms:(2) the effect of chelating agents solidified in cement. Small and full scale waste and other waste constituents on decontamination rad-forms collected from operating nuclear power plants I

NURl!G-1380 H-12

should h9 used in the lysimeter studies. (See also 4.

Assessimpact of ladiation on the performance of cc.

Section 11.2.2 dealing with field lysimeter studies.)

ment and bitumen-sohdified waste forms and ion-exchange resins. Determine mixed-field radiation 7.

Evaluate full-system decontamination LLW effects and radiolysis effects on solidified waste forms and on cement stabilization of waste form. Emphasize ion-exchange resins.

LOMI and CAN-DECON decontamination proc-Leachability of Activated Metals

esses, e

8.

Determine methods to retard leaching of Cs-137 Perf rm short and long term leaching studies of acti-vated metals collected from nuclear stations and decom-from cement-solidified L13V (e.g., by assessing ef-missioned nuclear facilities.

fects of adding zeolites to cement to retard leaching of Cs-137 from cement solidified LLW).

Regulatory Applications o

Testing to Determine the Effect of Chelating I

1 f

s Ik M

dem

^E nstituents on Decontamina-on 1

w !! be used to (1) develop regulatory guidance on waste form stability to meet Part 61 requirements,(2) provide a 1.

Assess the effect of chelating agents and other non-scientific basis for determining criteria for pedormance radiological constituents (including chemical com-specifications to ensure the stabilization of solidified pounds)in LLW on the release and transport of waste forms, (3) provide information for use in regulatory radionuclides from decontamination wastes.

reviews of process control programs and vendor topical reports,(4) provide information on short and long term 2.

Determine the chemical forms of radionuclides leaching, assessing releases of radionuclides, chelating leached from decontamination LI AV in the presence agents, and chemicals from LLW disposal facilities, (5) re-of chelating agents, and evaluate the radionuclide-duce, regulatory uncertainty regarding radionuclide and chelating agent complexes in leachates and releases chemical releases from solidified waste forms by prosid-from solidified waste forms.

ing realistic data for validatmg radionuclide source te,rm release and transport models, and (6) provide information on microbial, chemical, and radiation effects on stabilized 3.

Assess radiation degradation effects, biodegradation solidified waste forms, effects, and compicxing interaction with other waste.

Integration and Relationship to Other 4.

Perform long-term leach tests to characterize re-Research lease mechanisms and to determine the effects of oxidizing chemicals on ion exchange resins.

These studies have direct relationships to other research studies involved with (1) determinmg waste classification 5.

Determine the radiation effects of decontamination and characteristics of actuallow-level radwtste from nu-chemical solvents planned for use in light water re-clear power stations (see Sections 3.2.1 and 11.1.1),

actor decontaminations.

(2) screemng fests and tests to evaluate the long term performance for LLW form stability (see Sections 3.2.2 o

Testing to Determine the Effects of Chemicals, and ll.L2), (3) radionuclide and chemical source term de-Radiation, and liiodegradation on Stability of So, terminations (see Sections 3.t;.2 and 11.5.2), and (4) per-l lidified LIAV formance assessment evaluations of radionuclide and l

chemical releases from 11W facilities and transport in 1.

Determine the effects of radiation and chemicals on soil (see Sections 3.3.2 and H.2.2),

leaching and stability of solidified decontamination, evaporator concentrates, and other 11W using Products and Milestones small-and full-scale testing.

Work being performed by INEL FIN A6359 2.

Develop generic biodegradation test procedures for 1.

Collect solidified decontamination and evaporator regulatory qualification of LLW solidified waste waste from operating nuclear stations, FYs 1990 and forms.

j993, 3.

Determine the effects of biodegradation on solidi-2, Characterize waste and waste forms for radionuclide fled decontamination and evaporator LLW. Empha-and chemical content, FYs 1990 and 1991.

sis should be given to microbial activity using organ-isms from soil where LLW disposal facilities will be 3.

Collect activated materials from nuclear stations, located.

FY 1990.

11-1 3 NUREG-1380

1 >

t l

[

e Work to be performed by INEL FIN A6359 and I'IN arid and humid sites in typical 11W burial site kications, A6876 and the results should be compared with the results of short term laboratory tests. 'the strategy to meet the pro-1._

Complete long term leaching studies of solidified gram goal is as follows:

11W and activated metals, FY 1994.

e 1.

Prior to initiating new leaching experiments, data 2.

Complete studies of bk> degradation and chemical produced by previous experiments will be assembled and radiation effects on actual cement solidified and assessed to point out areas of high regulatory i

LLW, FY 1993.

uncertainty. Particular attention will be given to ex-isting lysimeter investigations. Results from NRC.

3.

Complete studies of decontamination radwaste and supported studies at Idaho National Engineering chelating agents, FY 1993, laboratory (INEL), Argonne National Laboratory (ANL), and Oak Ridge National laboratory 3

(ORNL) should be compared with the lysimeter data B.2.2 - Radionuelide Releases obtained by Pacific Northwest laboratories and Savannah River laboratory as part of DOE's Waste Program Goal Management Program, j

t

'lhe primary goal in this research ' area is to develop 2.

Lysimeter tests should be constructed using actual mechanistic models that describe the processes control.

cement solidified samples collected from operating ling radionuclide releases from LLW and that can be used nuclear power plants and activated metals obtained

~

for predicting radionuclide releases from LLW.

frem operating nuclear power plants or decommis-sioned nuclear facilities. For the field lysimeter stud-ies, solidified waste forms containing decontamina.

Background

tion, evaporator, and other radwaste streams should vary in size to include small, medium, and full scale y

- Radionuclide releases and transport from solidified waste wastes. S lidified samples should be prepared with forms and activated metals must be investigated under re-smd without the container metals of 55-gallon drums

- clistic disposal conditions. Such conditions can readily be or Meet Uncrs.

achieved in the laboratory, llowever, there are few data for leaching of solidified waste forms under field condi-3.

Studies using decontamination LLW data collection tions.This is partly because teaching of solidified waste is w 11 emphasize determining the chelating agent con-a slow process. Field testing of solidified 11W and acti-centration in soils in addition to measuring the I

ated metals with lys, meters, using natural precipitation radionuclide activities. *lhe field lysimeter leaching i

v t

- and measuring radionuclide and chermcal releases in soils results will be compared with laboratory leaching began at Savannah River, Oak Ridge, and INEL in the data'

_'carly 1980s, and this work is providing usefulinformation.

One particularly useful study is being done by INEL of 4.

To the maximum extent practicable, the models will EPICOR II, ion-exchange resins, This study is providing be developed and validated based on experimental data on radionuclide releases, but infor,mation from so-data from laboratory leaching experiments of LLW lidtfied cement contammg decontamination ion exchange obtained from operating nuclear power plants and end evaporator concentrates from actual nuclear power field lysimeter studies and trench leachate at exist-plants is urgently needed. Data on activated metal re-ing 11W disposal facilities, leases under controlled field conditions, e.g., lysimeter studies, are not available.

Regulatory Applications Research Strategy to Meet Program Goal Results from this research program will be used in the NRC LLW disposal regulatory and licensing process to It will be necessary to characterize the physical and (1) support the development of regulatory criteria for de-chemical processes that control radionuclide releases termining the stability of cement containing ion-exchange L fcom LLW and to develop mechanistic models that de-resin and evaporation LLWI (2) determine the leachabil-scribe these processes, it is also necessary to understand ity of radionuclides released from LLW in environments the effects of chelating agents and other nonradiological typical of present and future ILW disposal sites:(3) pro-constituents of LLW on the release and transport of vide radionuclide source term data (see Sections 3.6.2 and radionuclides, particularly from decontamination wastca.

II.S.2) and soil retardation data in natural environments:

The leachability of radionuclides, chelating agents, and (4) provide information on behavior of actual solidified chemicals from solidified waste forms and activated met-wastes containing ion-exchange resins, evaporator con-als should be assessed by using field lysimeters at both centrates, and activated metals under realistic burial

~

NUREG-1380 11-14

conditions for NMSS licensing reviews, standard review B.3.1 Long Term Performance of plans, and resolution of unresolved safety issues; and

}((gh. Integrity Containers (5) provide models for predicting radionuclide releases that can be implemented by NMSS staff in support of li-Program Goals censing and topical report reviews.

The objectives of this research program are (1) to evalu-ate the long-term performance of high integrity con-Integration and Relationship to Other tainer (HIC) materials being used or proposed for use for Research containment of l1W, and (2) to study the effects of radia-tion, microbial activity, and biogradation on the HIC matuials.

These studies have direct relationships to other research studies involved with (1) laboratory leaching studies (see Sections 3.3.1 and H.2.1). (2) source term studies (see

Background

Sections 3.6.2 and U.S.2), (3) radionuclide transport in Hecause they appear to afford extra protection to LLW, soils (see Sections 3.6.3 and H.S.3),(4) radionuclide trans-port models for determining radionuclide movement in high integrity containers (HICs) fabricated from con.

soils (see Sections 3.6.3 and H.5.3), (5) behavior of cret c. high-density polyethylene (H DPE), steel, and com-radionuclide chelating agent complexes in environtnent, posite materials are being developed or bemg used for the end (6) effects of chelating agents on radionuclide trans-disposal of certain types of LLW (e.g., dewatered non-port in soils from low level burial facilities.

exchange resms and filter sludge westes). It is anticipated that the concrete materials will include polymer impreg-nated concrete and fiberglass or steel mesh reinforced concrete. Composite materials include steel, fiberglass, Products and hiilestoncS or concrete containers composed of IIDPE and other plastic linings.

(Work being performed by IN!!L FIN A6359 and FIN A6876.)

Most of the proposed formulations for HICs are of very recent origin. Thus, their long-term performance is not established and must be (avestigated. The HIC must be 1.

Contmue with current lysimeter studies using.

structurally rigid to withstand the vertical and horizontal EPICOR 11 resins, FYs 1991-1993.

loads to which they will be subjected in an LLW disposal facility. In a technical assistance contract performed for 2.

Begin lysimeter studies using solidified decontami.

NMSS, it was determined that 0.5-inch. thick HDPE ma-nation 11W, FY 1991, terials would be structurally incapable of withstanding the loads that would be imposed in an LLW disposal facility.

cc H c ntainus are sW bdng used at th 3.

Begin lysimeter studies using HWR and PWR BarnwcH LLW disposal facility, decisions have to be evaporator concentrates, FY 1991.

made whether to require HDPE contamers to have thicker walls or to require an overpack of more rigid mate-4.

Begin lysimeter studies using activated metals, FY rials such as stecl or concretc.The lllC must also be capa.

1992.

ble of withstanding the effects of radiation, biodegrada-tion, and microbial activity.

5.

Monitor lysimeters and collect and evaluate Over the past few years, the NRC has received a large l

radionuclide and chemical reicases, FY 1999.

number of topical reports from vendors requesting ap-l proval of waste forms and containers for LLW disposal.

6.

Complete lysimeter studies and prepare formal re.

Conventional test methods, such as those of the Ameri-I port, FY 2001.

can Society for Testing Materials (ASTM), may not be ap-i plicable to certain waste forms and containers, particu-larly those that will be subjected to structural loading for hundreds of years. Research is therefore needed to estab-i B.3 Eng.ineered Harrier Performance lish test procedures and analytic methods that will ensure the long-term performance of the HIC.

There are three subelements in this program element-(l) high-integrity container performance, (2)

The NRC sponsored a research project at Brookhaven concrete performance, and (3) cover performance. The National laboratory (HNL) to develop an adequate data research strategy for dealing with them is illustrated in base for performance review of HDPE containers. The Figure H.3.

tests carried out under the research project included H-15 NUREG-1380

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creep testing to determine the failure /degredation mode 61.56 also requires that Class 11 and Class C waste forms for liDPli and irradiation-embrittlement tests to deter-

- or containers should be designed to remain stable, i.e.,

mine the effects of gamma radiation.The project was ter-maintain gross physical properties and identity over 300 minated at the end of FY 1988 both for lack of funds and years. To ensure that an lilC will maintain its stability, a for making management decisions on whether the NRC series of testing procedures have been proposed in the or the vendor should fund further research. In any case, NRC branch technical position on waste forms. 'the con-the issue will probably be revisited, particularly since firmatory work proposed here will provide an independ-liDPE containers were and are still being accepted at ent assessment that addresses a licensing need-that of llarnwell.

ensuring that the waste form will have structural stability.

It will also provide information that the licensing staff can

'the effects of sulfate, acid attack, and gamma radiation use in reviews of vendor topical reports on waste forms.

on concrete materials impregnated with polymers, fiberglass, or carbon need to be investigated. Irradiation InteEration and Relationship to Other m the form of gamma rays produces radiolysts of water m Research the cement paste that can affect its creep and shrinkage behavior. 'lhis applict both to the solidified LLW and t Results from this research program will provide inputs to the contamer.

,,ther areas in LLW research, specifically: (1) source term research (see Sections 3.6.2 and 11.5.2) will be provided Research Strategy to Meet Program Goals information develop,;d on breaching of containers and.

container failure mode, and (2)long-term cover perform-To resolve uncertainty with the long-term performance of ance (see Sections 3.4.3 and 11.3.3) will be provided with the iilC, particularly those made of IIDPE, the following information on container failures since these failures im-research is needed:

pact the amount of settlement and subsidence of LLW disposal facility covers.

1, lilC performance under structural loading should be tested. Tests should be conducted on a variety of Research on performance of container materials requires HIC materials, including those currently in use by input on (1) characteristics and performance of the con-vendors or being proposed for new LLW containers, tainer waste, e.g., chemistry of wastes, amount of radia-Preliminary measurements should be made in the tion, composition of the waste streams (see Sections 3.2.1, laboratory,smallspecimensof varyingwallthick-3.3.1,3.3.2 and H.I.1,11.2.1, and 13.2.2), and (2) properties ness over short periods of time (30-180 days). These of the backfill.

tests should be expanded to test full-scale lilC con-tainers if needed. Temperature during testing Products and Milestones should approximate the range that is likely to occur in an LLW disposal facility. Promising materials 1.

Complete development of testing protocol for should be evaluated in more detail at full scale and IIDPE, FY 1989.

the testing should be of longer duration (360-1000 days).

2.

Complete assessment of concrete container materi-als performance, FY 1994, if research is started in 2.

The long-term containment capability of the lilC FY 1990.

under loads imposed by chemical attack from within and without the container, by radiolysis, by microbial 3.

Complete assessment of composite container mate-attack, and by biodegradation should be evaluated.

rial performance, FY 1994, if research is staned in Testing should begin with small samples in the labo-FY 1990.

ratory and then be scaled up for the most promising materials. Accelerated testing will be required and 4.

Complete assessment of effects of radiation, will have to be accounted for in evaluating the con.

microbial activity, and blodegradation on HIC, FY tainment capability of materials under considera-1994, if research is started in FY 1990.

tion.

B.3.2 Long-Term Concrete Performance Regulatory Applications Section 61.56 of 10 CFR Part 61 stipulates that waste must have structural stability. Structural stability ctm be The objectivesof this research program are sixfold: (1)to provided by the waste form itself, by processing the waste assess the long-term durability of concrete under condi-to a stable form, or by placing the waste in an HIC or tions anticipated at LLW disposal sites, (2) to evaluate the structure that provides stability after disposal. Section long-term performance of barrier materials used in l

B-17 NUREG-1380

h I

3 1

?

l

~

L concrete construction, e.g., coating of interior and exte-determine changes in the concrete with time. To validate rior walls and joint scalants, (3) to assess the effects of.

and solve the mathematical models, accelerated tests will -

gamma radiation on concrete materials proposed for use be developed and conducted following ASTM proce-at LLW disposal sites, (4) to mathematically model the dures. Solutiens to the models will provide bases for pre-flow and transport of radionuclides through concrete over dicting the service life of the LLW disposal facility, the life of the LLW disposal facility,(5) to determine the r

extent and degree of chemical retardation provided by Restricting the ingress of water, and thus protecting un-J concrete to radionuclides, and (6) to determine the mini-derground LLW concrete structures, is an important part mal acceptable characteristics of waste forms placed in of the objective of ensuring 300-to-500-year service life of concrete structures.

concrete, llarrier materials, e.g., coatings of exterior and interior surfaces of the concrete orjoint scalants, need to be studied to ascertain the effects of oxidation and hy.

B:ckground.

drolysis and the action of alkalis, acids, biological agents,

.i Engineered disposal of LLW, i.e., engineered enhance-and radiation. long-term performance is the criterion for ment or engineered alternatives to shallow land burial, is selecting candidate barrier matenals. Most modern man-the most likely disposal technique to be adopted by most in de polymers are less than 100 years old and hence have States. One feature common to engineered methods of no long-tem pufgmance records. Research on barner

. LLW disposal is the use of concrete as the principal con.

materials will begm with a literature mvestigation fo!-

struction material. Observations of intact concretes from I wed by laboratory testing of material.

. the lloman Age suggest that certain concretes could mect Portland cement concrete possesses many of the physical the 300-to-500-year service life requirement for engi-qualities of an ideal radiation shield. Gamma rays can pro-neered enhancements at LLW disposal sites, llowever, duce radiolysis of water in the cement paste that can af.

the ancient concretes conta, cement that is quite differ-feet its creep and shrinkage belmvior and also result in m

ent from modern cement. Portland cement, considered to evolution of gas. The effects of gamma radiation on con-be the best of the modern cements, has demonstrated crete will be studied to include the effects on (1) materials been m,ent performance characteristics, but it,has only and additives of concrete, (2) mix properties, (3) sample excell use for a little over 150 years.The objective of the size, (4) temperatures, and (5) water / cement ratio. This

' concrete research is to extrapolate this expenence in w 11 be done by literature review and laboratory testing.

order to determine whether concrete can provide the 300-to-500-year service life.

Current models do not have the capability of assessing the 7

flow and transport of radionuclides through concrete. A

. Ilarrier materials, e.g., scaling coats and j.. t scalants, project currently under way at INEL (FIN A6858) is de-om

. are used to offer protection to concrete from the ingress veloping a mathematical scope model of the radionuclide i of moisture. Most manmade polymers used m mdustry, migration through concrete barriers for use with available K

are less than 100 years old and hence have no long-tem hydrologic transport models. Important information and perfonnance records. Thus, research is needed to study inputs for this research project will be provided from the the effects of degradation factors on barrier materials and concrete durability study at NIST.

predict their long term performance in addition to the ability to make service life predictions of concrete and The extent and degree of chemical retardation to barrier materials, mathematical modeling of the flow and radionuclides by concrete need to be assessed. The re-transport through concrete over the 300-to:500-year life search should look at the degree of retardation provided

, term must be conducted to evaluate the releases from by the concrete as a function of the materials and addi-concrete over the life of an LLW disposal facility. Also, tives in the concrete, the mix proportions, temperature, research on the credit that can be taken for chemical re-water /ccment ratio, and under both drying and wetting tardation of radionuclides by concrete must be under-conditions. The research should encompass laboratory

' taken in order that realistic LLW release rates from con-testing under controlled conditions and analysis of mate-crete waste forms can be estimated.

rials from the decommissioning of nuclear facilities.

Research Strategy to Meet Program Goals Regulatory Applications The NRC is sponsoring a research project at the National The NRC has technical requirements in 10 CFR Part 61

' Institute of Standards and Technology (NIST) to predict Subpart D that cover site suitability, design, operations, the service life of concrete exposed to an underground en-closure, and monitoring. The applicability of engineered vironment. The approach taken is first to identify the an-disposal systems to the Commission's requirements has ticipated deterioration processes affecting underground been assessed in NUREG/CR-3774, Volumes 1 and 2.

concrete. Next, degradation mechanisms of the concrete The general requirements of meeting the long-term per-deterioration process will be mathematically modeled to formance objective of 10 CFR Part 61 Subpart C is NUREG-1380 11-18

implicit for each disposal technique, and technical re-5.

Complete assessment of the degree of chemical re-quirements specifying the goals of waste isolation are di-tardation provided by concrete, FY 1993,if project is rectly applicable in all cases.

started in FY 1990.

1 The confirmatory work on long-term concrete durability IL3.3 Ung&rm Cover Performance will address a licensmg need of ensunng that proposed engiacered enhancements to shallow land burial using concrete willindeed perform their function for the serv.

Program Goals ice life of the disposal facility.

The objectives of this research program are sixfold: (1) to investigate infilitration of water through LIAV disposal Specifically, th.is research will provide the staff with a facility covers, (2) to assess t he rcliability of liners and cov-methodology to make predictions of the service life of ers in an 11W disposal facility, (3) to establish crosion i

concrete. It will help the staff to make assessments on the protection design criteria by performing research on I

long-term performance of barrier materials m, concrete carthen and rock covers, (4) to evaluate the infiltration and the effects of gamma radiation on the concrete for ex-through the covers,(5) to assess the long term stability of tended periods of time. Mathematical models on flow and an LI3V disposal facility as it pertains to settlement and transport through concrete will be developed. They will subsidence of the cover, and (6) to predict the long term i

constitute one of the requirements for makmg overall performance of the cover as an intruder barrier.

performance assessments of the 11W disposal sites. Re-search on chemical retardation provided by concrete will assist the staff in deciding the credits to be taken by con-Hackground crete for limiting radionuclide transport.

Infiltration of water through the covers and into waste is the foremost problem associated with near surface dis-3 Integration and Relationship to Other posal of 11W. When water infiltrates the cover or the Research sides of the disposal unit and contacts waste, radionu-clides can be leached from the 11W and transported out Results from this research program will provide inputs to of the disposal unit. Clearly,it is advantageous to reduce other areas in LLW research, specifically: (1)long-term water infiltration through the cover to as low a level as cover performance (cce Sections 3.4.3 and 11.3.3) since reasonably achievable.

deterioration of structural concrete used in an LIAV dis-posal facility is likely to affect cover integrity and peo Several components of an LLW disposal facility affect the formance; and (2) performance assessment (see Sections nfiltration of water. The quality and reliability of lmers, 3.6 and ll.5).This is an overall methodology for analyzing geotextile fabrics, filter matenals in covers, erosion pro-11W disposal facility system performance. Concrete per.

tection materials, and intruder barriers are important in formance, including its durability, its capacity for allowing this regard. Methodologies to evaluate mfiltration flow of water and any corresponding transport of through multilayered cover materials and into Ihe unsatu-radionuclides, and its potential for chemical retardation is rated zone surrounding the 11W facilities are highly un-one of the components that must be taken into account in certain. There are presently few if any known methods for the performance assessment methodology.

quantitatively determimng rock cover requirements to prevent initiation of gullies. The mtegrity of vegetative covers has been questioned in some parts of the arid west.

Products and Milestones For LLW facilities, limiting settlement and subsidence is of major importance for ensuring long-term stability of 1.

Complete methodology for predicting service life of the facility, particularly the cover. Currently there is no

?

concrete for 11W applications, FY 1992.

methodology available to model short-and long-term degradation of the 11W and/or the waste package with 2.

. Complete assessment of performance of barrier ma.

concomitant settlement of the 11W and loss of integrity terials in concrete, FY 1993, if research is started in of the covers resulting in ingress of moisture and/or re-FY 1990.

lease of radioactively contaminated gases.

3.

Complete assessment of effects of gamma irradia-Research Strategy to Meet Program Goals tion on concrete materials, FY 1993, if research is started in FY 1990.

To meet program goals in controlling water infiltration through covers, emphasis has been given to the problems 4.

Complete mathematical modeling of flow and trans-of humid sites. Field experiments on cover performance port through concrete, FY 1990. (Work is being per-are being conducted in large lysimeters (45' x 50' x 12') by formed by INfit FIN A6S58.)

the University of California at flerkeley and the 11 - 1 9 NURl!G-1380

k University of Maryland (FIN 138958) at Ilcitsville, Mary-Research st PNLindicating that vegetation could provide land. These lysimeters are designed to give a complete adequate protection against erosion complements the ra-

- water balance, and the covers installed in them are don barrier by maintaining a desired moisture content in

- insrumented to evaluate water infiltration.Three of the the soil and reduces water infiltration so that teaching is covers being assessed are multilayer covers.

minimized. In the area of rock covers, the NRC has spon-sored hydraulic fiume studies at Colorado State Univer.

All use compacted clay as a barrier (resistive layer barrier) sity. A data base has been established and some recom-to deep water percolation through the cover. One cover mended actions made to provide NRC with a basis fot

- consists solely of clay overlaid with vegetated topsoil.The approving erosion protection designs. Additional re.

- second consists of rip-rap over the clay layer, 'the third search work will be needed to gather data from fiume design consists of a capillary barrier system beneath a clay testing involving soil and rock covers to determine soil layer Construction of these three multilayer covers was and rock cover durability and establish detailed design re-completed in the winter of 1988-89, and data collection view procedures relevant to long-term stabilization of on the covers' effectiveness has begun.

LLW disposal facilities.

Multilayer covers such as those just described will not Intruder barriers contemplated for LLW disposal facili-withstand appreciable subsidence. To address this prob, ties tnclude rip-rap and/or concrete. Research on the du-lem, another design is being assessed. This design, called rability of the rip-rap will be covered under that for cro-a bioengineering cover, employs (1) a surface engineered sion protection using rock. Intruder barriers using cover of impermeable pancis whose function is m en-concrete wdi be m, vestigated in conjunction with work on hance runoff and reduce infiltration, and (2) vegetation the long-term durability of concrete (see Section 3.4.2 planted in narrow openings between panels whose func.

and 11.3.2).

- tion is to remove the small amount of water that passes through the covec.The i.mpermeable pan:Is are designed Regulatory Applications to flex and, since they are at the ground curface, any subsi-dence is easily managed. The bioengineering covers were The work described above is based on regulatory needs completed for two lysime!cis in 1987. To test their effec-expressed in 10 CFR Part 61. Several sections of Part 61 tiveness, both lysimeters were filled with water (1 meter address the requirement forlong term stability of the dis-in one,2 meters in the other). Ily 1989 this system of engi-posal facility, which includes ensuring integrity of the cov-neered enhanced runoff and environmentally stressed ers. Section 61.13 states that analyses must be performed vegetation has dewatered both lysimeters.The long-term to determine the effects of crosion, mass wasting, slope ability of the vegetation to survive is now being assessed.

failure, settlement of masses and backfill, and infiltration of water on the long term stability of covers. The analyses No research at the present time addresses the load defor-must provide reasonable assurance that the cover will

- mation response of the LLW disposal facility and the reli-perform such that there will not be a need for ongoing ac-ability of liners and filter materials. The long term stabil-tive maintenance of the site following closure. Sec-ity of geotextiles, materials that may be used as liners and tion 61.51 states that covers must be designed to mini.

filters, needs to be studied. Research needs to be con-mize w>ter infiltration to the extent practicable, to direct ducted to develop analytical tools and models capable of perce' ng or surface water away from the disposed analyzmg the effects on the multiple components of the wast (.md to resist degradation by surface geologic proc-cover materials due to the short and long term degrada-esses and biotic activities. Section 61.7 states that con.

tion of the LLW forms followed by consolidation and set-crete covers used as intruder barriers should have an ef-I tiement. The models should be useful for compiling, cal-fective life of 500 years.

culating, and comparing predicted and actual settlement l

and subsidence in existing LLW facilities Integration and Relationship to Other 8##

in regard to an infiltration evaluation methodology, Pa-1 cific Northwest Laboratories (PNL)(FIN 112934) is col-The passage of water through the covers applied over L

lecting necessary information through laboratory experi.

LLW disposal facilities affects performance of all other ments,- field experiments at PNL, and computer parts of the disposal system. Thus, work in this area is simulations. The resulting methodology will incorporate linked to work on waste form performance (Sections 33.1 parameters that significantly influence long-term esti-and B.2.1), radionuclide releases (Sections 3.3.2 and mates of infiltration such as physical processes, material 11.2.2), long term concrete performance (Sections 3.4.2 properties, engineering features, and climatic conditions.

and 11.3.2), monitoring (Sections 3.5.2 and 11.4.2), per-formance assessment (Sections 3.6 and 11.5), and a new Most research on crosion protection has focused on the project being performed for NMSS by the Corps of Engi-use of vegetative and rock cover for uranium tailing piles.

neers on laboratory testing and field placement of NUREG-1380 11-20

low permeability soils used for LLW disposal unit covers B,4.1 Site Characterization l

(FIN D1995).

I Program Goals j

Products and Milestones The research goals are twofold: (1) to examine method-3 ologies for characterizing potential LLW disposal sites for

(

l.

Publish final results on performance of bioengineer-the processes and conditions critical to site and facility ing water management, FY 1992. (Work being per-performance so they can be identified for evaluation dur-l formed by the University of California at flerkeley ing the license review process, and (2) to provide the in-f under FIN B8958.)

formation on techniques and procedures that may be used i

to establish baseline data for comparison to operational l

2.

Publish final results on performance of resistive and post-operational monitoring data so that the impor-i layer barriers, FY 1994. (Work being performed by tant system and subsystem behavior of the LLW disposal l

the University of California at Berkeley under FIN facilities durmg those phases can be evaluated. Such in-

)

B8958.)

f rmation and methodology ate especially needed for the i

next generation of11W sites that will probably be kicated in the unsaturated zone.

3.

Publish final results on performance of rip-rap over compacted clay, FY 1994. (Work being performed l

by the University of California at Berkeley under

Background

j FIN B8958.).

Prelicensing data collection (site characterization) issues can be grouped according to the uncertainties inherent in j

4.

Publish final results on performance of resistive the techniques, methods, and/or procedures used. Site l

layer barriers over capillary barrier, FY 1994. (FIN characterization methods and procedures have been de-H8958.)

veloped over the years for siting various waste disposal systems and large scale facilities (e.g., nuclear power 5.

Complete assessment of long-term durability of plants). NUREG-1199 and NUREG-1200 discuss the in-geotextile, FY 1995, if research is started in FY formation that the ticensee should address in a licensc ap-

1990, plication for an LLW disposal facility and include a sec-tion on " Site Characteristics" with the following l

6.

Complete modeling methodology for load deforma-subsections: Geography, Demography, and Future De-

[

tion of LLW disposal facility, FY 1992, if research is velopments; Meteorology and Climatology; Geology and -

l started in FY 1990.

Seismology; Hydrology; Geotechmcal Characteristics;-

Geochemical Characteristics; Natural Resources; Biotic E"

7.

Complete compilations and calculations of settle-thse camgorks, te"nQm, meMs, ng.

mos ments of existing LLW sites using developed meth-

"n pr cedums am maQaHaMor obtaining the de-i odology, FY 1993, if research is started in FY 1990.

stred site-specific mformation. However, for hydrology and geochemical characteristics, which are central to the 8.

Complete establishment of design criteria for rip-evaluation of the performance of the LLW site and facil-2 rap protection of soil covers, FY 1992, if research is ity, research studies are needed.

started in FY 1990.

To date most standardized methods have been developed 9.

Complete infiltration evaluation methodology, FY for evaluating hydrologic and geochemical properties as-l 1992. (Work being performed by PNL under FIN sociated with saturated media. Previous research studies H2934.)

by NRC and DOE contractors have examined limited site characterization techniques and monitoring for L1W sites in saturated media (e.g., West Valley, New York;

10. Complete assessment of long-term performance of Maxey Flats, Kentucky; and Oak Ridge. Tennessec).

intruder barriers, FY 1993, if research is started in

,These earlier studies have provided sufficent information FY 1990.

so that further research into site characterization meth-ods for high-permeability and porous saturated units is not needed. Ilowever, characterization methods and pro-B.4 Site Character.ization and cedures for asessing the siting of LLW disposal facilities Monitoring in extremely low-permeability saturated hydrogeologic units (e.g., clay units) or unsaturated units are needed. In (Fig. H.4 illustrates the research strategy for addressing particular, the research should focus on techniques appli-this program element.)

cable in low moisture (arid) environments, the long term B-21 NUREG-1380

,5 zC:c mC b

g TO 5

SITE CHARACTERIZATION & MONITORING STRATEGY

' PERFOMANCE I

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I WATER MONITORING NN E

CHARA GM g

Y SURFACE C

ND VANATION WATER WATER HYDROt.OGY HYDROLOGY "E

m CUMATIC EFFECTS I

1 t

MNTED m

SITE DRAINAGE u

DEFFERENT PATI. WAYS 1

WATER GEOMOFFHsC r

men TABt.E 1.AND MCOtF.

POSTCl,OSURE StTE GROUND WATER DRAINAGE MODfFICATION PROPERTIES FACIU1Y mamm OF EFFE m SOtt/ WATER WATER

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DEGREE OF k

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Figure B.4 Research strategy for Site Characterization and Monitoring program element.

' l

~ --

& =

V durability of unsaturana mne monitoring systems, and conduct research necessary to determine characteri-

. assessment of monitoring parameters as indicators of fa-zation needs, evaluate new methods nnd techniques cility performance. Recent research studies funded by the for meeting these needs, and recommend methods

- NRC, DOE, and EPA indicate that the greatest uncer-and techniques following laboratory and field test-tainty and need lie in development of site charactcrization ing methods for unsaturated systerns below the root zone that

. may be encountered at future 11W facilities given the re-2.

Identify site characterization requirements for vari-

._ quirements in 10 CFR Part 61.

ous types of sites (e.g., unsaturated site conditions) l that would represent the complexity of the ground-

- The present NRC research program is examining site water flow and transport system in a conservative characterization methods for unsaturated zone disposal manner (i.e., heterogeneous and anisotropic flow (Pacific Northwest laboratories (PNL) and New Mexico and transport properties for both saturated and un-State University (NMSU), FIN B2934, and Massachu-saturated media). Where site characterization re-

- setts Institute of Technology (MIT), FIN D2044) as part quirements or methods for the site processes or con-of a fic!d validation study near las Cruces, New Mexico.

ditions are not well defined, conduct research g

Research Task 1 of FIN D2044 with MIT is designed to necessary to assess existing requirements and meth-l address site characterization and monitoring strategies odology, and make recommendations for additions for LLW facilities located in the unsaturated zone. The or modifications to the NRC licensing staff, interaction between data needs, spatial heterogeneity, rad modeling at an LLW site are being addressed in the 3.

Examine site characterization techniques necessary

(

MIT research. To date, the studies have demonstrated to capture sufficient detail of site heterogeneity and l

that much usefut information can be obtained by using ex-site processes necessary for later use in performance isting soil science methods in conjunction with models re-assessment.

cently developed as part of these research tasks. How-ever, to fully characterize and model an unsaturated or 4.

Determine site characterization needs for modeling arid site for three-dimensional flow and transport consid-liquid and vapor phase transport in unsaturated and crations,large-scale field experiments are being designed saturated (liquid phase) flow and transport. Specifi-and executed.

cally, identify and assess alternative techniques for l

determining ambient and variab!c moisture content i

Remaining work to be pursued by the PNL, NMSU, and and pressure head that affect ground-water move-i MIT investigators include assessment of simultaneous va-ment and contaminant transport in the unsaturatcJ por and liquid movement and its transport potential; zone (i.e., including the presence of perched movement of reactive contaminants through unsaturated ground-water zones) at LLW disposal facilities.

media: examination of diagnostic in situ soil chemistry as an indicator of infiltration, percolation, and recharge rates; evaluation of coupled tension and moisture content Regulatory Applicat,ons i

i measurement techniques for extremely dry material (i.e.,

Sect.i n 61.50, " Disposal Site Suitability Requirements t:nsions exceeding 15 bars); development of fic!d and laboratory techniques for developing moisture retention for land Disposal," of 10 CFR Part 61 requ,res that an i

and characteristic curves for the full range of site condi-LLW site shall be capable of bemg charactemed, mod-tions (i.e., very dry to near saturated conditions), and Cled, analyzed, and momtored. Furthermore, the LLW ground water chemistry sampling techniques for low s tmg criteria require disposal above the water table and Its zone f fluctuation unless it can be demonstrated that, moistare content and high tension conditions.

for LLW disposal below the water table, diffusion pre-dominates over advective transport of radionuclides.

Research Strategy to Meet Program Goals These two considerations have necessitated research into unsaturated zone processes and site characterization The following strategy is being used to meet the research techniques. Since the capability of present practices to i

program goals:

adequately and accurately characteiize an unsatunted site is in question, additional information 5 needed by the L

Lixamine site characterization data collection needs NRC licensing staff and/or State agency in older for them as outlined in NRC's standard format and content to be able to review the anticipated upcoming license ap-for an LLW disposal facility license apnlication plications.

(NUREG-il99, Rev.1) and standard revinv plan foran LLW disposal facility (NUREG-1200 ;. rela-Ongoing research activities under FIN 132934 at PNLand 1

l tionship to the performance assessment determina-New Mexico State University at the 12s Cruces field site l

tions and findings required under Part 61. Where are addressing this question. PNL will produce reports the data collection methods are not well established, that will provide information of regulatory use on:

11 - 2 3 NUREG-1380

1,. Evaluation of state-of-the art unsaturated zone in-3.

Complete development of ASTM standards on un-strumentation and methodology to be used (e.g.,

saturated zone field techniques (presently not NRC-porous-cup tensiometers, Guelph permeameters, funded), FY 1992.

suction samplers);

s 4.

Complete development of ASTM standards on un-

' 2.

Parameters and conditions that need to be collected saturated and saturated site characterization that (e.g., saturated and unsaturated hydraulic conduc-yould be applicable to the next generation of LLW tivity, moisture contents, pressure heads); and sites, FY 1995.

3.

Uncertainty associated with the measurements (c.g.,

Complete evaluation of methods for assessing inter-5.

spatial and temporal).

action and performar.cc of site engineered systems with flow and transport in the unsaturated zone, FY 1994.

Integration and Relationship to Other 6.

Complete assessment of field techniques to evaluate Research simultaneous vapor and liquid movement and their transport potential, FY 1995.

Since the physical conditions of the site of an LLW facility ultimately determine the eff.:ctiveness of efforts to iso-7.

Complete field testing of suction lysimeters for sam-late the LLW, site characterization studies are directly re-pling movement of reactive contaminants through lated to performance assessment activities. Current re-unsaturated media under strong tensions, FY 1993.

search projects such as the validation studies of ground-water flow modeling (i.e., HYDROCOIN) and 8.

Complete evaluation of diagnostic ground water geosphere transport modeling (i.e., INTRAVAL) have chemistry as an indicator of infiltration, percolation, site-characterization-related aspects. This relationship and recharge rates, FY 1993.

derives from the data needs for model input and analysis of field results to model output.

9.

Complete evaluation of coupled tension and mois-t ure content measurement techniques for extremely Site characterization and monitoring research are closely dry material, FY 1994.

related in that many of the techniques and methods for developing data are common to both. Furthermore, the B.4.2 Monitoring LLW unsaturated zone hydrology studies are also closely related to the high-level waste unsaturated zone hydrol-ogy studies at the University of Arizona (FIN D1662)and Pmgrani Goah.

the Sandia National Laboratories (FIN A1266) dealing 1.

To develop a methodology for monitoring ground-with unsaturated flow and transport in fractured media.

water flow and radionuclide transport at an LLW LLW research studies central to resolving site characteri-disposal site for both operational and post-zation issues are part of the INTRAVAL project, which operational periods such that both natural processes allows for the irteraction of all RES-funded unsaturated that may affect the facilities' performance and radio-zone studies involving performance assessmen t, site char-nuclide and contaminant pathways are actively aeterization, and monitoring (i c., Apache Leap Tuff Site observed and quantified, and and Las Cruces Trench).

2.

To examine the interrelationship between engi-Information on site characterization for surface hydrology nected system performance and the natural setting.

issues (e.g., flooding and crosion assessments) will be ex-Important natural systems and subsystems behavior, amined using earlier research related to uranium mill tail.

including their relationships to engineered system ings and nuclear power plant siting (e.g., Linsley, Kraeger performance during the construction, operation,

& Associates, and Colorado State University),

and post-closure phasex of an LLW facility by op-eratior, must be observed. Various ground-water flow and transport processes such as infiltration, Products and Milestones percolation, recharge, and liquid and vaporcontami-nant movement, as well as the identified pathways, L

Complete assessment of infiltration evaluation must be monitored.

methodology under FIN 112934 by PNL, FY 1990.

2.

Complete assessment of alternative field monitor-ing techiques for the unsaturated zone under FIN Monitoring issues at an LLW site involve both the con-112934, FY 1991.

tinuation of data collection activities begun during site NUR EG-1380 11 - 2 4

characterization and initiation of monitoring for assessing and recommend a monitoring strategy (INEL site and engineered rystem performance. Monitoring of A6853).

ground water flow for large-scale engineered facilitics (e.g., dams) and contaminant transport at waste disposal 2.

Identify monitoring requirements for disposal in sites is not a new venture. Much is presently known about (1) low permeability saturated units and (2) unsatu-ground water flow monitoring strategies (e.g., EPA guid-rated media. Where monitoring requirements or ance and requirements for hazardous waste sites) and methods are not well defined, conduct research nec-techniques for high-permeability units such as aquifers.

essary to assess requirements and methodology and However, monitoring of low-permeability saturated units make recominendation to the NRC. PN11NMSU such as clays associated with disposal pond liners and/or (H2934) and MIT (D2044) are addressing unsatu-covers for wasse disposal sites is still under development rated media. Monitoring of low-permeability satu-by EPA and the private sector (e.g., EPRI). EPA and car-rated units is not yet being addressed.

lier AEC studies have examined release of contaminants, both radioactive and nonradioactive, through both 3.

Examine site monitoring techniques and strategies ground-water and atmospheric pathways. Previous NRC.

necessary to determine effects of natural processes funded projects for uranium mill tailings and LLW sites on the facility performance (MIT D2044, PNil (e.g., Maxey Flats, Kentucky, and West Valley, New NMSU B2934,INEL A6853).

York) have examined monitoring strategies and tech-4.

Determine monitoring needs in unsaturated (liquid niques for saturated and pardally saturated flow systems.

and vapor) and saturated (water) zones. Specifically, identify and assess alternative techniques for moni-Several NRC-funded research studies deal with monitor-toring moisture movement and contammant trans-ing of arid sites whcie extremely low-water-content me-p rt in the unsaturated zone at LLW disposal facih-dia must be monitored and sampled.The high-tevel waste tks.

studies at Yucca Mountain by DOE and related RES co-nfirmatory studies are also investigating unsaturat ed zone 5.

Determine monitoring needs applicable to engi-momtonng. In particular, PNL and New Mexico State nected systems (e.g., concrete structures) (INEL Umversity (FIN B2934) are presently assessmg momtor-A6853)'

ing techniques as part of their field validation studies near las Cruces, New Mexico (Section B.4.1). In related work on high levebwaste site characterization, the University Regulatory Applications of Arizona (FIN D1662) is examining monitoring tech-10 CFR 61.50, " Disposal Site Suttability Requirements,"

niques for unsaturated conditions in fractured media.

requires that an LLW site shall be capable of being char-acterized, modeled. analyzed, and monitored. Further-INEL(FIN A6853)is mvestigatmg information require-more, the LLW siting criteria require disposal above the ments for performance assessment at the time of facility water table and zone of fluctuation unless it can be dem-closure. That work has identified covers and long term onstrated that, for LLW disposal below the water table, concrete durability as being the two most important items diffusion predominates over advective transport of to be monitored. INEL is also examining the impact of radionuclides. These two considerations have necessi-post-closute ecological changes on facility performance.

tated the pursuit of research into unsaturated zone site After completing an assessment of these factors, INEL monitoring techniques. This is particularly important in will make momtormg recommendations to the NRC.

the arid Western United States where the water table is commonly deep below the land surface. However, finding Future research w ll focus on the durability and reliability sites in the humid Eastern United States with a thick un-i of monitoring techniques for long time periods (e.g., up to saturated zone will be difficult. Therefore, some States 100 years) for a variety of possible site conditions (e.g.,

are considering disposal in low-permeability saturated transient recharge cond;tions). Other research topics in-media below the water table. Because of this, there is a clude the effect of engineered systems and inadvertent in-regulatory need for monitoring techniques capable of trusion scenarios on monitormg strategies.

demonstrating that molecular diffusion is the principal transport mechanism.

Researcli Strategy to Meet Prograin Goals 10 CFR 61.53 requires that environmental monitoring systems provide early warning of radionuclide releases.

1.

Identify site monitoring needs in relationship to per-Most monitoring plans have concentrated on monitoring formance assessment determinations and/or find-in wells at or below the water table. Since many future ings to be made under 10 CFR Part 61. Where the LLW disposal facilities. particularly in the arid Western monitoring methods are not well established. con-United States. will dispose of waste in the unsaturated duct research necessary to assess various methods zone, there is a need to detect and trace contaminant B-25 NUREG-1380 m.,

movement in the unsaturated zone close to disposal units.

Products and Milestones MIT (D2044) is assessing site characterization and moni-toring stratet; a for 11W facilities located in the unsatu.

1.

Complete reports by PN!)NMSU (H2934) on the rated zone 'lhe interaction between data needs and the Las Cruces, New Mexico, field site on instrumenta-spatial heterogeneity of an 11W site are being addressed tion being used to monitor moisture in the unsatu.

m the MIT research.

rated rone, parameters being collected, and the spa-tial and temporal uncertainty associated with the Another monitoring licensing issue is the need for ade, measurements, mid FY 1989.

quate and accurate data for the performance assessment 2.

Complete report by INEL (FIN A6853) on identifi-methodology used to demonstrate compliance with the performance objectives in Part 61. This regulatory need cation of information and analyses needed to assess to relate monitoring to performance assessment is the fo-the performance of an 11W dtsposal facility, mid cal point of INEL's work on the information needed at the FY 1989.

time of closure (A6853) and the MIT(D2044) and PNIJ 3.

Complete report by INEL (FIN A6853) on long-NMSU (H2934) interaction at the lats Cruces field site.

The important performance measures (i.e., hydraulic po-term ecological changes actmg on an LLW disposal tentials, moisture contents, and tracer breakthrough dis-I"c ity following cessation of operations, late FY g9 tributions)nre being closely examined for the im Cruces trench experiments (i.e., test #1 steady-rate application expenment and test #2 varied applimtion experiment),

Complete report by INEL(FIN A6853)on LLW dis-4.

Both experiments, as described in PNL and NMSU pubh-posal facility permanent closure and recommenda-tions on information needed for performance mod-cations, discuss monitoring protocols and data vanability.

eling, late FY 1989.

The long-term durability of unsaturated zone monitoring systems for long time periods and for extremely dry and/

5.

Complete assessment of infiltration evaluation or variable conditions is an additional future research methodology under FIN H2934 by PNL, FY 1990.

topic.

6.

Complete assessment of ehernative field monitor-NUllEG-1199, llevision 1, outlines information needed ing techiques for the unsaturated zone under FIN in the LLW license application on "Postoperational Envi-B2934, FY 1991.

ronmental Monitoring and Surveillance." The NitC li-censing staff has identified an important monitoring issue 7.

Complete assessment of monitoring systems for related to the reliability of existing methods for unsatu-analysis of coupled natural setting-engineered sys-rated zone menitoring and the need to identify and assess tems for both saturated and unsaturated conditions alternative techniques for monitoring moisture move-(i.e., concrete / ground water interaction), FY 1994.

ment and contaminant transport in the unsaturated zone at LLW disposal facilities. Ongoing research activities of 8.

Complete assessment of long-term durability of PNL under FIN H2934 and of New Mexico State Univer-11W monitoring instrumentation, FY 1993, sity at the las Cruces field site are addressing this regula-I tory need for monitoring.

9.

Complete assessment and recommendations on monitoring requirements for disposal in low-Integration and Relationship to Other Research B.5 Perfonnance Assessment As discussed in the preceding section on site characteriza-tion, momtonng is closely linked to site characterization (Fig. B.5 illustrates the research strategy for addressing (Section !!.4.1) and performance assessment (Section this program element.)

11.5). The ongoing studies by PN!JNMSU and MIT are part of a field validation project of unsaturated flow and B.5.1 Performance Assessment Pathway transport models that also includes site characterization Model Evaluations as well as assessment of monitoring techniques. This work l

is also closely related to high level-waste site characteri-program Goals zation studies dealing with unsaturated flow and trans-port through fractured media, and model validation stud-Performance assessment requires an overall methodol-l ies at the University of Arizona (FIN D1662) and ogy and requisite computer programs to analyze the con-performance assessment studies at the Sandia National tribution from different pathways to the total system per-laboratories (FIN A1266).TheINELwork(FIN A6853) formance of an LLW disposal site. The goal of the is also linked to performance assessment.

research is to ensure that (1)a methodology :s in place for

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' evaluating different pathways over a variety of site condi-portance of the pathways, and (3) assess the effect of l

= tions; (2) the pathway models are technically defensible hydrogeologic heterogeneity on the ground-water path-j cnd implemented in a computer program for use in the

way, methodology; (3) there is a methodology for determining radionuclide and chemical transport, behavior, pathways, uptake, transfer coefficients, and dose calculations to in.

Regulatory Applicat. ions

' dividuals and populations following release from LLW A performance assessment will be necessary to determine disposal facilities; and (4) there is an adequate data base if the site and engineering design of an LLW site comply for validating radionuclide transport models.

with the dose limits of Part 61.

Background

Integration and Relationship to Other A performance assessment methodology will be neces-sary to evaluate the safety of an LLW disposal site. NMSS The pathway model evaluations will make use of and pro-is currently funding Sandia National Laboratories (SNL) vide feedback to all the LLW research projects, particu-to develop an LLW performance assessment methodol-larly the work on waste form performance (Sections 3.3.1 ogy (PAM). The PAM is comprised of both models and and B.2.1), radionuclide releases from LLW disposal fa-e assumptions that cover the various transport pathways cilitics (Sections 3.3.2 and B.2.2), long-term performance (e.g., air, sub-surface water, and surface water) and path-of high-integrity containers (Sections 3.4.1 and B.3.1),.

{

ways to man (e.g., plant uptake)and dose models. Many of long-term concrete performance (Sections 3.4.2 and these models are based on accepted methods that have B.3.2), site characterization ( Sections 3.5.1 and B.4.1),

i been used in other parts of the fuel cycle (e.g., dose mod-monitoring (Sections 3.5.2 and B.4.2), source term (Sec-cls, air transport models, and surface water models). The

.tions 3.6.2 and B.5.2), radionuclide transport at LLW models and assumptions of the methodology must be sites (Sections 3.6.3 and B.5.3), and the PAM project at j

- technically defensible for their intended use. Research is SNL being performed for NMSS. Specifically, this project 1

needed to examine the PAM for adequacy of the concep-will make use of model development and data collection tual models, validity of assumptions built into the models, performed in other projects while providing feedback to I

and limitations in the data.The significance of the differ-those same projects to help direct the research toward ar.

ent pathways needs to be analyzed to direct PAM toward cas of most importance to performance assessments.

pathways that have the most influence on demonstrations liance with the performance objectives of 10 CFR Products and Milestones Begin new project in FY 1991 to evaluate pathway models and their significance to performance assessment, with Research Strategy to Meet Program Goals the following milestones.

i The research will evaluate the relative sigr.if.cance of 1.

Complete an evaluation of the significance of differ-

- various exposure scenarios and radionuclidt transport ent pathways at the end of the first year of this pathways to identify the entical data and assessments hav-project, FY 1991. The evaluation will consider the mg the most influence on demonstrations of compliance validity of the pathway models as well as data re-with the performance objectives m 10 CFR 61.41 and qmmments.

61.42, which establish dose limits to the public from radio-active materials released to the environment from the fa-2.

Complete modification and documentation of path-ctlity and to an madvertent intruder after the site is en-way models' lY 1992' closed. It should be integrated with the SNL PAM to support selection and review of models and tools for per-3.

Complete an evaluation of scenarior appropriate to formance assessments.

LLW disposal at the end of the second year of the project, IY 1991 The evaluation will address the Initially, research should be performed to ensure that all dose limits of "ut 61.

the parts (e.g., ground-water model, air transport model) of the SNL PAM are defensible. While many of the sub-models of the PAM (e.g., air transport, dose to man, plant B.5.2 Source Term uptake) will rely on " standard" models, it is anticipated that special attention will be ' required to (1) analyze the Program Goal PAM for adequacy to evaluate the various pathways over the range of site conditions anticipated for LLW disposal, The primary goal is to develop a predictive model of the (2) understand the effect of concrete barriers on the im-rate of radionuclide release at the disposal unit boundary NUREG-1380 B-28

to be used as input to radionuclide transport models in the a preliminary assessment of the quantity and rate of geosphere.

radionuclide release at the disposal unit.

Research Strategy to Meet Program Goals

Background

UNL has produced a model for the determination of the The NRC requirements for an LLW disposal facility, source term, which is based on a simplified conceptual 10 CFR Part 61, specify that the facility must be capable model of an LLW disposal trench filled with carbon steel of being characterized, modeled, analyzed, and moni.

drums containing cemented waste. 'lhe model is prelimi-tored. Accurate performance assessment modeling will nary and warrants further refinements and validation depend on the accuracy of the initialinput to the model.

based on laboratory experiments, in situ tests, and field The source term represents the initial input to models studies. While the model is general enough to allow for predicting radionuclide transport in the geosphere. A complete breach of a waste container followed by instan-generalized model of the source term must provide the taneous release and transport, the model cannot predict a quantity and rate of release of radionuclides at the dis.

gradual release of radionuclides due to the degradation of posal unit boundary, which involves an estimation of the an HIC or HDPE container. The teach component of the physical, chemical, and hydrological processes influenc.

model is limited to leaching from a cement waste form, ing the release.

The strategy for future source term work is as follows:

(1) develop models for leaching of bitumen and vinylester styrene, (2) obtain leach data from different waste

'lhe prediction of a source term at the disposal unit boundary is a difficult task due to the variety of waste streams (at present, all models are mdependent of the w ter chemistry),(3) couple the transport to a geochemi-forms, containers, radionuclide inventory, and disposal cal speciation code such as EQ3/6, (4) the source term practices. An LLW disposal facility may contain a diverse m del will be benchmarked against lysimeter test and m inventory 'f radionuclides, both short and long lived.The situ data, (5) validate the model using natural and ar-waste form may vary greatly from cement solidified de-cheological analogs, and (6) perform sensitivity analyses contaminated resins, resins, liquids, paper products, acti-to determine critical processes influencing the release vated metals to contaminated animal carcasses. Waste an transport and to &nMy ahmal apMmmal containers may include carbon steel drums, high. integrity work and data collection.

containers (HICs), and high-density polyethylene (HDPE) containers to name a few. Individual containers may be closely packed, contacting one another, or may be Regulatory Applications surrounded by a soil or cement backfill. Hence, a source Source term modeling is an essential ingredient of per-term model must be general enough to handle the vari-formance assessment, and it will provide input for model-ations m facility design, radionuclide inventory, container ng radionuclide transport to the accessible environment, degradation, and radionuclide release, a requirement for licensing an LLW site.The source term model will also be useful in identification of the important The NRC has funded the Brookhaven National Imbora-processes and parameters that need to be controlled to tory (UNL) under FIN A3276 to develop a preliminary, minimize the release of radionuclides from LLW disposal generalized source term model, incorporating the four units. In addition, sensitivity and validation studies will processes critical to the estimation of a source term:

lead to an identification of gaps in data for which critical (1) water infiltration through the disposal unit cover, experiments may be designed and performed.

(2) container degradation. (3) radionuclide release from the waste form, and (4) transport to the disposal unit Integration and Relationship to Other boundary. W,ater mfiltration through the cover is pro-Research jected by application of FEMWATER, a computer pro-gram for unsaturated flow, which assumes an initial flux of Under FIN A3276, HNL has provided a framework for a water to the waste package. Container degradation is ad-source term model.This project provides the release rate dressed by the Dreach model, which is based on corrosion of radionuclides at the disposal unit boundary, which will of carbon steel and contains two models, generalized and enable the licensing staff to predict the performance of a pitting corrosion. This model enables calculation of thc proposed site during the review of a license application.

time to contamer failure for as many contamers as speci-This program also provides a research tool for determin-fled. Radionuclide release from the waste form is ad-ing the relative importance of the various barriers in the dressed by the Leach model, which contains four options:

disposal unit and identifying future research needs for en-two diffusion models, dissolution, and rinse. FEM-hancing safe disposal practices.

WASTE is coupled with the output from the Leach model to provide transport to the disposal unit. The Breach.

Recommendations and data from other research projects Leach, and Transport code (Blll') provides the means for will be used in the model. The llLT code will be updated B-29 NUREG-1380

as recommendations from other projects are received.

11.5.3 Transport of Radionuclides and

'ihe specific projects are long term performance of high-Chemicals at LLW Disposal Sites integrity containers (Sections 3.4.1 and 13.3.1), waste char-acterization (Sections 3.2.1 and 11.1.1), waste forms and Program Goals waste package performance (Sections 3.3.1 and 11.2.1),

control of water movement through disposal unit covers

'Ihe goal of this program is (1) to collect and develop envi-(Sections 3.4.3 and 11.3.3), and radionuclide releases from ronmental data to use in assessing environmental behav-the LLW disposal facility (Sections 3.3.2 and B.2.2).

ior of radionuclides and validate radionuclide and chemi-cat tnmsport models at LLW disposal sites, and (2) to The llLTcode developed under FIN A3276 will be used determine radionuclide and chemical transport, behavior, by licensing in the LLW performance assessment meth-pathways, uptake, and transfer coefficients of radionu-odology contract at Sandia National laboratories. The clide and chemical releases from LLW disposal facilities.

output from this code should serve as input to transport calculations in a performance assessment.

Background

Products and Milestones The geochemical environment at an LLW disposal site will play a key role m the transport and behavior of 1.

Complete identification and compilation of radio.

radionuclides and other chemicals. The initial ground-logical and chemical characteristics of waste, devel, water composition will be altered as it mixes with the opment of a systematic trench model from invento.

leachate from the waste. Once the radionuclides and rics of existing disposal sites indicating the amount other chemical contaminants have entered the ground ~

and placement of waste in a typical trench, and col, water, the environment will either enhance or retard the lection of leach data from different waste streams, movement of the radionuclides. However, the actual FY 1990.

mechanisms and controlling parameters are not well un-derstood. Conceptual models and co 7 uter programs 2.

Modification to the llLT code will be made accord-have been developed to handle c WIS Mm chemical lag to the following schedule:

speciation and reaction paths. Howevu ' general these codes have not been validated with actual field data.

Geochemical codes have not successfully coupled trans-a.

Complete degradation models of alternative port codes with hydrologic transport models. Geochemis-waste forms such as IllC and HDPb contam-try is generally accounted for by a single parameter-a re-ers, particularly with regard to release from tardation factor. Transport programs that use a partially failed contamers, FY 1990.

retardation factor may be adequate if the geochemical en-vironment site is fully characterized for both liquids as b.

Complete a coupled diffus. ion-dissolution well as solids and adequate Kd data are collected at the teach model, bitumen teachmg model, vmyles-proper water composition, pH, Eh, and soil chemistry for ter styrene leaching model, FY 1990.

cach particular site being licensed. However, such an ap-proach fails to take into consideration the complexities as-c.

Complete a ccapled hydrochemical or geo-sociated with contaminant transport in the near. surface chemical speciation model of radionuclide environment. Soil to-plant uptake factors and radionu-transport within disposal unit, FY 1991.

clide transfer coefficients involving various plant leaves and roots represent major factors in determining the d.

Complete development of simplified source transport of radionuclides in the environment for which term model for licensing purposes by making information on 10 CFR Part 61 radionuclides is not avail-Ill a stand-alone code FY 1992.

ab!c. Existing assumptions about radionuclide migration, including C-14 and H-3 as described in Regulatory Guide 4.

Complete source term model (BLT) sensitivity 1.109 concerning radionuclide transfer coefficients, are analysis to determine key parameters and processes not suitable for 10 CFR Part 61 assessments.

influencing radionuclide release and transport, to aid in trench design, and to identify additional ex-Research Strategy to Meet Program Goals perimental work, FY 19!0.

As with other research efforts, the radionuclide transport 5.

Complete benchmarking the source term model research strategy is to concentrate in the areas of greatest against lysimeter tests and in situ data, FY 1991.

uncertainty and potentially important phenomena. A general program must be undertaken to study tmnsport l

6.

Complete model/ code validation using natural (ar-of contaminants in the near surface. Studies should in-l cheological) analogs, FY 1993.

clude identification and development (if necessary) of a l

NURI!G-1380 Il-30 l

model for radionuclide retardation mechanisms, includ-Waste characterizauon (Sections 3.2.1 and B.I.1) will ing surface complexation, identification of the critical sur-provide chemical inforroation on various waste forms and face sites, ion exchange, precipitation and dissolution, waste streams. Waste form performance (Sections 3.3.1 sorption, matrix diffusion, and effect of soil composition and B.2.1) will provide data that may be used by this pro-on sorption. Studies should include laboratory experi-gram. Information from this program (Section B.S.3)will ments to determine transfer coefficients as well as field be used in the scenario evaluation under performance as-studies at act ual disposal sites where there has been trans-sessment (Section H.5).

port. Field studies should identify the chemical form of the migrating radionuclide and chelating complexes Products and Milestones where chelating agents may affect radimuclide transport.

' Studies should also include the role played by biotic proc-Investigate radionuclide transport under unsaturated and esses, organic complexants, and particulates in enhancing saturated flow conditions according to the following -

or retarding radionuclide movement. Finally the ques-schedule:

tions of vapor phase transport and model validation must be addressed. To address a portion of the above, a grant 1.

Complete determination of retardation mecha-has recently been awarded to the Johns Hopkins Univer-nisms-surface complexation, ion exchange model, sity to develop a coupled hydrochemical transport code, precipitation / dissolution, physico-chemical sorp-tion, matrix diffusion-for important radionuclides, FY 1993.

Particular attention will be given to improving the ability to predict migration behaviorof C-14 and H-3. Research 2.

Complete assessment of protocols for determining will be done to assess (1) the partitioning of C-14 and H-3 between air and ground-water pathways, (2) their migra-retanU.m coefficients for predicting radionuclide py 399 tion rate in air and ground water, and (3) the extent to which they can be taken up in vegetation. Initial priority 3.

Complete assessment of the role played by soil /

will be given to C-14 release, transport, uptake, transfer ground water composition in controlling radionu-to plants, and its behavior in the environment. Source clide movement, FY 1991.

- tcrm estimates will be made from specific LLW streams I

at operating nuclear power plants and institutional waste-4.

Complete assessment of the interactions of compet-Study of the behavior of C-14 in ground water will be em-ing ions in the ground water and the effect on j

phasized. The chemical forms of C-14 will be studied.

radionuclide transport, FY 1991.

Soil to-plant transfer coefficients will be determined first by small laboratory pxperiments that will be confirmed by 5.

Complete assessment of the role played by non-i field measurements of soil, atmosphere, and vegetation at radiologic waste package components in enhancing existing disposal sites to determine rates of releases and radionuclide transport, User Need B.2, FY 1991.

l fluxes from sites.The translocation factors from root to stem to leaves will be determined for vegetation expected 6.

Complete assessment of the role of organic com-to be present at LLW disposal sites. The soil-gas-to-plexants and microparticulates in radionuclide mi-atmosphere to-leaves-of-plant pathway will be studied as gration, FY 1992.

l well as the ground-water-to-soil pathway to detctTnine how important the C-14 pathway is in LLW disposal.

7.

Complete assessment of(a) the partitioning of C-14 and H-3 between air and ground-water pathways, and (b) the rate of their migration in air and ground Regulatory Applications water and the extent to which they can be taken up l

by plants, FY 1993.

'Ihis information will be used by the NRC staff to validate, 8.

Complete development of data base for validating use, and review computational models for prediction of contaminant transport at mill tailings LLW disposal sites radionuclide, chelating agem, chemical transport, i

uptake, and behavior and pathway m~h@ following and for charactenzation and performance assessment of releases to environment from LLW facilities, FY I

LLW disposal sites.

1993.

9.

Complete assessment of the role played by biotic Integration and Relationship to Other processes in enhancing radionuclide movement, FY Research 1992.

The geochemical effects on radionuclide transport at

10. Complete determination of the extent of vapor LLW disposal sites will use data and results from research phase transport of C-14 and H-3 in the unsaturated contract recommendations.

zone, FY 1992.

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4 noi 2207 BIBLIOGRAPHIC-DATA SHEET t$ne instructens on the reverse) -

2. il1LE AND SUSillLE NUREG-1380 3,

DATE REPORT PUBLISHED Low-level Radioactive Waste Research Program Plan l

u AH uw-November 1989

4. FIN OR GRANT NUMBER

6. TYPE OF REPORT

b. AUTHOR (S)

Research Plan E. O'Donnell, J. Lambert 7 PE RiOO cove REo va<' >> t oe'e>>

FY1990 - FY1992 8.

F HM N NIZ AT ION - NAM E AND ADDRESS (if NRC, provem Deressa. Offste er Reeson, U.S Nucarar Revu4 tory Communen, one mesmo ensress. se sentrusor.proww Division of Enginee' ring Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission Washington, DC 20555 9, SPONSORING ORG ANIZ ATION + N AME AND ADDRESS ur NRC. tree "seme +5 eteve". d' roalterfor.ProvN8' NRC Ostd88en, Offste or Regen. U.S Nucieer Repuferory Commasuen, cne meums omtressi Same as 8, above.

10. SUPPLEMENT ARY NOTES

11. ABST R ACT (Joo nersi or arns The plan provides an integrated framework for planning the LLW research program to ensure that the program and its products are responsive and timely for use in NRC's LLW regulatory program. The plan discusses technical and scientific issues and uncertainties associated with the disposal of LLW, presents programmatic goals and objectives for resolving them, establishes a long-term strategy for conducting necessary confirmatory and investigative research needed to meet these objectives, and includes schedules and milestones for completing the research. Areas identified for investigation include waste form and other material concerns, failure mechanisms and radionuclide releases, engineered barrier performance, site characterization and monitoring, and performance

' assessment.

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ML19351A680

Contents

Text

1.1 Purpose and Scope

SUBJECT:

Enclosure:

Background

Background

Background

Background

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ML19351A680

Text

1.1 Purpose and Scope

SUBJECT:

Enclosure:

Background

Background

Background

Background

Background

Background

Background

Background

Navigation menu

Search