i'~~

WM DOCKET CONTROLCENTER

'86 DEC -5 Al31:3VWITASCAConsulting Group, Inc.

1 December 1986

Dinesh GuptaU.S. Nuclear Regulatory CommissionDivision of Waste ManagementWashington, D.C. 20555

"NRC Technical Assistancefor Design Reviews"Contract No. NRC-02-85-002FIN D1016

Dear Dinesh:

Enclosed with this letter is our draft of "Suggested ReviewApproach to In-Situ Testing at Yucca Mountain (Section 8.3.3,Planned Tests, Analyses, and Studies-Seal System Program)".

We look forward to discussing these drafts. Please call me,Daemen, or Roger Hart if you have any questions.

Jaak

Sincerely,

or n J. Lorng

cc: D. Tiktinsky

Encl.ljl/ks

W M Vdl

Mstriution-__ __. ..-

WM Project Q.ILI, lDocket No.

PDR 'LPDR E/f h, ZS5)

6612220160 61201 sPDR WMRES EECITAS -D-1016 PDR a

__ ,

(Retumr to W, 623-SS).. _ .

P.O. Box 14806 * Meapolis, Minnesota 55414 * (612) 623-9599

Jay,/

DRAFT

SUGGESTED REVIEW APPROACH TO IN-SITU TESTING AT YUCCA MOUNTAIN(Section 8.3.3, Planned Tests, Analyses, and Studies

- Seal System Program)

TABLE OF CONTENTS

PAGEI. Areas of Review

II. Acceptance Criteria

A. Applicable Rules and Basic Acceptance Criteria

(1) 10CFR60 §60.17 - Contents of SiteCharacterization Plan.

(2) 10CFR60 Part 60 §60.21 - Content of LicenseApplications

3. 10CFR Part 60, §60.31 - ConstructionAuthorization

4. 10CFR Part 60, §60.43 - License Specification

5. 10CFR Part 60, §60.46 - Particular ActivitiesRequiring License Amendment

6. 10CFR Part 60, 60.51 - License Amendment forPermanent Closure

7. 10CFR Part 60, 60.72 - Construction Records

8. 10CFR Part 60, §60.112 - Overall SystemPerformance Objective for the Geologic RepositoryAfter Permanent Closure

9. 10CFR Part 60, §60.122 - Siting Criteria

10. 10CFR Part 60, §60.134 - Design of Seals forShafts and Boreholes

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TABLE OF CONTENTS (continued)

PAGE

11. Regulatory Guide 4.17 - Standard Format andContent of Site Characterization Plans forHigh-Level Waste Geologic Repositories

12. Annotated Outline for Site Characterization Plans,Revision 4, February 15, 1985' Prepared by MutualAgreement of BWIP, NNWSI, SRP, and DOE-HQ

13. NRC SCP Reviews As Specified in the Nuclear WastePolicy Act of 1982, Public Law 97-425-January 7,1973, Sec. 113,(b),(1),(A),(ii).

14. Generic Technical Positions (GTPs)

B. Specific Technical Criteria

1. Technical Review Preliminaries

2. Seal System Program Review

8.3.3.1 - Overview

8.3.3.2 - Seal System Environment

8.3.3.3 - Seal System Components andInteraction Tests

8.3.3.4 - Seal System Optimization

8.3.3.5 - Seal System Modeling

REFERENCES

D R A F T

SUGGESTED REVIEW APPROACH TO IN-SITU TESTING AT YUCCA MOUNTAIN(Section 8.3.3, Seal System Program)

8.3.3 PLANNED TESTS, ANALYSES, AND STUDIES - Seal System Program

I. Areas of Review

The applicant must present information concerning the sealingproducts, methods, and procedures that will be used to sealan eventual repository in unsaturated tuff at Yucca Mountain,Nevada. Performance of the seals in accordance with minimumrequired performance as determined by performance analysismust be demonstrated. This will require demonstration ofseal system component performance in the environment in whichthe components are to be emplaced, as well as demonstrationof acceptable emplacement methods and technology. Stabilityof the sealing materials and of the rock in which they areemplaced must be demonstrated. The assessment of the proper-ties and stability of the rock should be consistent with re-lated SCP Sections. Much of the information discussed inthis section may be presented in other sections-in whichcase, it may be cross-referenced rather than repeated here.

The staff review covers the following specific areas:

(1) Seal System Environment (Subsection 8.3.3.2);

(2) Seal System Components and Interaction Tests(Subsection 8.3.3.3);

(3) Seal System Design Optimization (Subsection8.3.3.4); and

(4) Seal System Modeling (Subsection 8.3.3.5)

Coordination will be required to ensure that the informationprovided as input for sealing is deemed adequate by the pri-mary reviewers of geology, geoengineering, hydrology, geo-chemistry, climatology and meteorology, and repositorydesign.

DRAFT OUTLINEPage 2

II. Acceptance Criteria

A. Applicable Rules and Basic Acceptance Criteria

The applicable rules and basic acceptance criteria pertinentto this SCP Review Plan are:

(1) 10CFR60 §60.17 - Contents of Site Characterization Plan.

The Site Characterization Plan shall contain "a descrip-tion of such site characterization activities, includingthe following-. . . (iii) Plans for any investigationactivities that may affect the capability of such area toisolate high-level radioactive waste; (iv) Plans to con-trol any adverse impacts from such site characterizationactivities that are important to safety or that are im-portant to waste isolation . .

If a narrow definition of Acceptance Criteria is to befollowed, the next sections will be referenced: NWPA(1982), Regulatory Guide 4.17, and GTP Borehole and ShaftSealing. If a broad definition of Acceptance Criteria isto be followed, various relevant sections of 10CFR60 willbe identified.

(2) 10CFR60 Part 60 §60.21 - Content of License Appli-cations

(a) An application shall consist of general informationand a Safety Analysis Report.

(b) The general information shall include

"(5) A description of site characterization work actuallyconducted by DOE at all sites considered in the applica-tion and, as appropriate, explanations of why such workdiffered from the description of the site characteriza-tion program described in the Site Characterization Re-port for each site.

(c) The Safety Analysis Report shall include:

DRAFT OUTLINEPage 3

(1) A description and assessment of the site at which theproposed geologic repository operations area is to be lo-cated with appropriate attention to those features of thesite that might affect geologic repository operationsarea design and performance. The description of the siteshall identify the location of the geologic repositoryoperations area with respect to the boundary of the ac-cessible environment.

(i) The description of the site shall also include thefollowing information regarding subsurface conditions.This description shall, in all cases, include such infor-mation with respect to the controlled area. In addition,where subsurface conditions outside the controlled areamay affect isolation within the controlled area, thedescription shall include such information with respectto subsurface conditions outside the controlled area tothe extent such information is relevant and material.The detailed information referred to in this paragraphshall include:

(A) The orientation, distribution, aperture in-fillingand origin of fractures, discontinuities, and heteroge-neities;

(B) The presence and characteristics of other potentialpathways such as solution features, breccia pipes, orother potentially permeable features;

(C) The geomechanical properties and conditions, includ-ing pore pressure and ambient stress conditions;

(D) The hydrogeologic properties and conditions;

(E) The geomechanical properties; and

(F) The anticipated response of the geomechanical, hydro-geologic, and geochemical systems to the maximum designthermal loading, given the pattern of fractures and otherdiscontinuities and the heat transfer properties of therock mass and groundwater.

(ii) The assessment shall contain:

(A) An analysis of the geology, geophysics, hydrogeology,geochemistry, climatology, and meteorology of the site.

DRAFT OUTLINEPage 4

(B) Analyses to determine the degree to which each of thefavorable and potentially adverse conditions, if present,has been characterized, and the extent to which it con-tributes to or detracts from isolation. For the purposeof determining the presence of the potentially adverseconditions, investigations shall extend from the surfaceto a depth sufficient to determine critical pathways forradionuclide migration from the underground facility tothe accessible environment. Potentially adverse con-ditions shall be investigated outside of the controlledarea if they affect isolation within the controlled area.

(C) An evaluation of the performance of the proposed geo-logic repository for the period after permanent closure,assuming anticipated processes and events, given therates and quantities of releases of radionuclides to theaccessible environment as a function of time; and a simi-lar evaluation which assumes the occurrence of unantici-pated processes and events.

(D) The effectiveness of engineered and natural barriers,including barriers that may not be themselves a part ofthe geologic repository operations area, against the re-lease of radioactive material to the environment. Theanalysis shall also include a comparative evaluation ofalternatives to the major design features that are impor-tant to waste isolation, with particular attention to thealternatives that would provide longer radionuclide con-tainment and isolation.

(F) An explanation of measures used to support the modelsused to perform the assessments required in paragraphs(A) through (D). Analyses and models that will be usedto predict future geologic setting shall be supported byusing an appropriate combination of such methods as fieldtests, in situ tests, laboratory tests which are repre-sentative of field conditions, monitoring data, and na-tural analog studies.

DRAFT OUTLINEPage 5

(2) A description and discussion of the design, both sur-face and subsurface, of the geologic repository opera-tions area including: (i) the principal design criteriaand their relationship to any general performance objec-tives promulgated by the Commission, (ii) the designbases and the relation of the design bases to the princi-pal design criteria, (iii) information relative to mater-ials of construction (including geologic media, generalarrangement, and approximate dimensions), and (iv) codesand standards that DOE proposes to apply to the designand construction of the geologic repository operationsarea.

(4) A description of the quality assurance program to beapplied to the structures, systems, and components im-portant to safety and to the engineered and natural bar-riers important to waste isolation.

(6) An identification and justification for the selectionof those variables, conditions, or other items which aredetermined to be probable subjects of license specifica-tions. Special attention shall be given to those itemsthat may significantly influence the final design.

(11) A description of design considerations that are in-tended to facilitate permanent closure and decontamina-tion or dismantlement of surface facilities.

(14) An identification of those structures, systems, andcomponents of the geologic repository, both surface andsubsurface, which require research and development toconfirm the adequacy of design. For structures, systems,and components important to safety and for the engineeredand natural barriers important to waste isolation, DOEshall provide a detailed description of the programs de-signed to resolve safety questions, including a scheduleindicating when these questions would be resolved.

(vi) Plans for permanent closure and plans for the decon-tamination or dismantlement of surface facilities."

DRAFT OUTLINEPage 6

3. 10CFR Part 60, §60.31 - Construction Authorization

"Upon review and consideration of an application and en-vironmental report submitted under this part, the Commis-sion may authorize construction if it determines:

(a) Safety. That there is reasonable assurance that thetypes and amounts of radioactive materials described inthe application can be received, possessed, and disposedof in a geologic repository operations area of the designproposed without unreasonable risk to the health andsafety of the public. In arriving at this determination,the Commission shall consider whether:

(1) DOE has described the proposed geologic repositoryincluding but not limited to: . . . (iv) constructionprocedures which may affect the capability of the geo-logic repository to serve its intended function."

4. 10CFR Part 60, §60.43 - License Specification

"(a) A license issued under this part shall include li-cense conditions derived from the analyses and evalua-tions included in the application, including amendmentsmade before a license is issued, together with such addi-tional conditions as the Commission finds appropriate.

(b) License conditions shall include items in the follow-ing categories:

(5) Controls to be applied to restricted access and toavoid disturbance to the controlled areas and to areasoutside the controlled area where conditions may affectisolation within the controlled area."

5. 10CFR Part 60, §60.46 - Particular Activities RequiringLicense Amendment

"(a) Unless expressly authorized in the license, anamendment of the license shall be required with respectto . .

(6) Permanent closure."

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DRAFT OUTLINEPage 7

6. 1OCFR Part 60, §60.51 - License Amendment for PermanentClosure

(a) The DOE shall submit an application to amend the li-cense prior to decommissioning. The application shallconsist of an update of the license application and en-vironmental report submitted under S60.21 and 60.22,including: . . .

(4) The results of tests, experiments, and any other an-alyses relating to backfill of excavated areas, shaftsealing, waste interaction with the host rock, and anyother tests, experiments, or analyses pertinent to thelong-term isolation of emplaced wastes within the geolo-gic repository."

7. 10CFR Part 60, §60.72 - Construction Records

"(a) DOE shall maintain records of construction of thegeologic repository operations area.

(b) The records required under paragraph (a) shall in-clude at least the following:

(1) Surveys of the underground facility excavations,shafts, and boreholes referenced to readily identifiablesurface features or monuments;

(2) A description of the materials encountered;

(3) Geologic maps and geologic cross-sections;

(4) Locations and amount of seepage;

(5) Details of equipment,methods, progress, and sequenceof work;(6) Construction problems;

(7) Anomalous conditions encountered;

(8) Instrument locations, readings, and analysis:

(9) Location and description of structural support sys-tems;

(10) Location and description of dewatering systems; and

DRAFT OUTLINEPage 8

(11) Details, methods of emplacement, and location ofseals used."

8. 10CFR Part 60, §60.112 - Overall System PerformanceObjective for the Geologic Repository After PermanentClosure

"The geologic setting shall be selected and the engi-neered barrier system and the shafts, boreholes and theirseals shall be designed to assure that releases of radio-active materials to the accessible environment followingpermanent closure conform to such generally applicableenvironmental standards for radioactivity as may havebeen established by the Environmental Protection Agencywith respect to both anticipated processes and events andunanticipated processes and events."

9. 10CFR Part 60, 60.122 - Siting Criteria

"(a)(1) A geologic setting shall exhibit an appropriatecombination of the conditions specified in paragraph (b)of this section so that, together with the engineeredbarriers system, the favorable conditions present aresufficient to provide reasonable assurance that the per-formance objectives relative to isolation of the wastewill be met.

(b) Favorable conditions

(8) For disposal in the unsaturated zone, hydrogeologicconditions that provide-

(i) Low moisture flux in the host rock and in the over-lying and underlying hydrogeologic units;

(ii) A water table sufficiently below the underground fa-cility such that fully-saturated voids contiguous withthe water table do not encounter the underground facil-ity;

(iii) A laterally extensive low-permeability hydrogeolo-gic unit above the host rock that would inhibit the down-ward movement of water or divert downward moving water toa location beyond the limits of the underground facility;

DRAFT OUTLINEPage 9

(iv) A host rock that provides for free drainage . . .

(c) Potentially adverse conditions. The following condi-tions are potentially adverse conditions if they arecharacteristic of the controlled area or may affect iso-lation within the controlled area.

(1) Potential for flooding of the underground facility,whether resulting from the occupancy and modification offloodplains or from the failure of existing or plannedman-made surface water impoundments.

(2) Potential for foreseeable human activity to adverselyaffect the groundwater flow system, such as groundwaterwithdrawal, extensive irrigation, subsurface injection offluids, underground pumped storage, military activity orconstruction of large scale surface water impoundments.

(20) Rock or groundwater conditions that would requirecomplex engineering measures in the design and construc-tion of the underground facility or in the sealing ofboreholes and shafts.

(23) Potential for existing or future perched water bod-ies that may saturate portions of the underground facil-ity or provide a faster flow path from an underground fa-cility located in the unsaturated zone to the accessibleenvironment.

(24) Potential for the movement of radionuclides in agaseous state through air-filled pore spaces of an unsat-urated geologic medium to the accessible environment."

10. 10CFR Part 60, §60.134 - Design of Seals for Shafts andBoreholes

"(a) General Design Criterion. Seals for shafts andboreholes shall be designed so that following permanentclosure they do not become pathways that compromise thegeologic repository's ability to meet the performanceobjectives or the period following permanent closure.

(b) Selection of Materials and Placement Methods. Mater-ials and placement methods for seals shall be selected toreduce, to the extent practicable:

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DRAFT OUTLINEPage 10

(1) The potential for creating a preferential pathway forgroundwater to contact the waste packages or

(2) For radionuclide migration through existing path-ways."

11. Regulatory Guide 4.17 - Standard Format and Content ofSite Characterization Plans for High-Level Waste GeologicRepositories

This guide provides information, recommendations andguidance and, in general, describes a basis acceptable tothe staff that may be used to implement the requirementsof 10CFR Part 60, §60.17 - Contents of Site Characteri-zation Plan.

The specific requirements of Regulatory Guide 4.17 rele-vant to sealing are found on p. 4.17-35 and require theapplicant to

* Describe the proposed treatment of the disturbed sec-tion of rock around openings and excavated surfaces.

* Describe proposed design measures to control ground-water movement into the facility.

* Provide laboratory and field data when available andinferred site conditions on which the selection of thetreatment measures was based.

* Describe the proposed design for the sealing of bore-holes and shafts.

*Provide laboratory and field data and inferred siteconditions on which the design was based.

* Provide the mechanical, chemical, and hydrologicproperties of proposed sealing materials.

12. Annotated Outline for Site Characterization Plans, Revi-sion 4, February 15, 1985' Prepared by Mutual Agreementof BWIP, NNWSI, SRP, and DOE-HQ

This document presents a detailed outline of the SCP inaccordance with 10CFR Part 60, §60.17 and RegulatoryGuide 4.17.

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DRAFT OUTLINEPage 11

13. NRC SCP Reviews As Specified in the Nuclear Waste PolicyAct of 1982, Public Law 97-425-January 7, 1973, Sec.113,(b),(1),(A),(ii).

14. Generic Technical Positions (GTPs)

Borehole and Shaft Seals (Final), February 1986

Design Information Needs in Site Characterization Plans(Final), December 1985

B. Specific Technical Criteria

1. Technical Review Preliminaries

Review of Section 8.3.3, Seal Systems Program, will re-quire familiarity with a number of directly-relatedsections-in particular,

*Section 1.6 - Drilling and Mining - This section willtabulate the location and characteristics of all drillholes and excavations at and near the site and willprovide available information on the effects of the ac-tive and abandoned wells, boreholes, and excavations onthe principal hydrogeologic units.

This information will provide guidance as to the typeof sealing equipment that might be required at thesite. It will assist in identifying the need, if any,for demonstrating:(1) sealing of active and abandoned wells, boreholes,

and excavations;

(2) re-entry of same; and

(3) remedial action (e.g., cleaning) of same

*Section 2.8.3 - Changes in Geoengineering PropertiesDue to Excavation

Changes in hydraulic conductivity and porosity of therock adjacent to excavations could influence sealingperformance and requirements .g., by sealing enhancedbypass flow paths around seals or by reducing freedraining.

DRAFT OUTLINEPage 12

* Section 6.1.5 - Barriers Important to Waste Isolation

This section will provide a description of the reposi-tory barriers such as tunnel backfill and repositoryand borehole seals.

* Section 6.2.5 - Shaft and Ramp Design

Construction (excavation, reinforcement-support) andlining concepts under consideration will be of particu-lar concern. These openings could provide direct(waterflow, airborne) paths to the accessible environ-ment.

* Section 6.2.7 - Backfill of Underground Opening

This section will identify the need for backfill anddecommissioning seals. If required, preliminary mater-ials, specifications, the functions, handling, and em-placement concepts will be provided.

* Section 6.2.8 - Shaft and Borehole Seals

* Section 6.3.5 - Sealing of Shafts, Boreholes, and Un-derground Openings

* Section 6.3.6 - Construction

This section will describe how the construction of ex-ploratory workings at the site will not compromise theintegrity of the site.

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DRAFT OUTLINEPage 13

* Section 8.3.5.2 - Strategy for Postclosure PerformanceAssessment

In particular: 8.3.5.2.1 (Engineered Barrier Sub-system); and 8.3.5.2.2 (Seal Systems Performance Goals)

Supplementary or supporting sections will need to bereviewed, or an assessment of this validity provided byother reviewers, or it is certain that essential inputinformation will have to be obtained from a variety ofsources (including, for example, Geoengineering, Hy-drology, Geochemistry, Climatology and Meteorology, Re-pository Design). In sum, seal program review requiresfairly comprehensive understanding of a variety of re-pository aspects. As such, an in-depth seal programreview can be obtained only through a multi-discipli-nary effort.

2. Seal System Program Review

Section 8.3.3 will summarize the seal systems test pro-gram and provide an overview of the research and develop-ment activities required to ensure that the repositoryseals and backfill system is capable of satisfying appli-cable design and performance objectives.

According to the "Annotated Outline", the planned studiesand tests will explain

* why the test, study or analysis is planned and whatdata and information will be obtained

* how the results will be used to help resolve specificinformation needs

* what methods techniques, and data analysis will be used

* limitations and uncertainties of test methods and dataanalysis

* representativeness, precision, and accuracy of proposedtest methods and data analysis

* significant options or alternative test methods anddata analysis to those proposed

DRAFT OUTLINEPage 14

The discussion of in-situ testing of seals will include

* a description of tests that might use radioactive ma-terials

* a description of tests that might affect the capabilityof the site to isolate waste

* a summary of instrumentation and monitoring.

If no such tests are planned, Chapter 8 will explain whythese tests are unnecessary in order to provide suffi-cient data for licensing. If the final decision on suchtests will depend on results of preceding tests, the SCPwill describe the logical steps which lead to the deci-sion.

* Section 8.3.3.1 - Overview

The overview section will state the purpose of the sealsprogram and will provide an overview of the seals program.The section will describe the interrelations and the se-quencing of the primary activities of the program.

* Section 8.3.3.2 - Seal System Environment

This section will identify and describe the lists and an-alyses needed to establish the repository seal and backfillenvironments. These lists and analyses will define thephysical and chemical characteristics that influence thedesign, installation (construction), and performance of therepository seals.

The major concern for the NRC seal program reviewer will bethe completeness of this section as well as the prioritiza-tion of various information needs.

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DRAFT OUTLINEPage 15

It is likely, and acceptable, that much of the informationneeded for the characterization of the seal systems en-vironment will be provided by reference to other sectionsof the SCP-i.e., the necessary information is likely to beobtained as part of the general site characterization in-vestigations rather than specifically and exclusivelywithin the sealing program. Providing assurance of com-pleteness about the information, therefore, will requireparticular care. Obtaining assurance about the adequacy ofspecific information items will require confirmatory reviewinput from other disciplines (in particular, geochemistry,hydrology, geology, geophysics, meteorology, and geoengi-neering).

The following aspects of the seal system environment needto be determined:

(1) physical environment

* temperature

* deformations (Deformations to which seals are likelyto be, or might be subjected subsequent to emplace-ment. This might include seismically- or tectoni-cally-induced deformations.)

* stresses/loads (Stresses applied to emplaced seals-e.g., as a result of continuing or re-activated rockdeformation, backfill load, water and/or gas pressureand/or flow.)

* chemical environment

- temperature- rock chemistry (mineralogy)- water chemistry- reaction products form rock/seal/water interactions- water/gas flow rates and/or pressures

* hydrological environment

- degree of saturation- waterflow/pressure- groundwater chemistry- precipitation/infiltration- perched water

* construction influence parameters

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* Section 8.3.3.3 - Seal System Components and Interac-tion Tests

This section will identify and describe the following.

* seal system component tests, including component-environment interaction testing

* repository backfill tests and studies.

Of particular concern in this regard should be theinfluence of emplacement procedures on eventual sealsystem performance.

Other factors that need to be evaluated include

* completeness of component-environment interactiontesting (completeness of environment simulations)

Particularly difficult are likely to be

- simulations of rock/liner/support/seal deterior-ations over prolonged periods of time

- long-term hydrological changes (e.g., drainage,changes in the hydrological environment as a re-sult of waste-induced thermal pulse-for exam-ple, drying-wetting cycles)

correlation between design/performance requirementsand tests

An evaluation of the adequacy of the proposed seal com-ponent testing will require a determination of the re-quired components. This, in turn, will require anidentification of the types of seals needed. Thisdepends on the types of structures to besealed-particularly as identified in the followingsections:

DRAFT OUTLINEPage 17

Section 1.6 (Drilling and Mining)

3.2.2 (Flood Protection)

6.1.1 (Repository Design Requirements)

6.1.4 (Barriers Important to Waste Isolation)

6.2.2 (Overall Facility Design)

6.2.4.2 (Flood Protection)

6.2.5 (Shaft and Ramp Design)

6.2.6 (Subsurface Design)

6.2.7 (Backfill of Underground Opening)

6.2.8 (Shaft and Borehole Seals)

6.3 (Assessment of Design Information Needs)- particularly,

6.3.5 (Sealing of Shafts, Boreholes andUnderground Openings)

6.3.6 (Construction)

6.3.8 (Repository System ComponentPerformance Requirements)

Component Tests

* physical, mechanical, hydrological, thermal, chemicalcomponent characterization

* emplacement tests

DRAFT OUTLINEPage 18

Component/Environment Interaction Tests

* mechanical (swelling/shrinkage, stress/displacement,interface strength, relative strength, relativestiffness)

* thermal (hydration heat-confinement effect)

* hydrological (interface flow paths)

* geochemical (bond, interaction)

Section 8.3.3.4 - Seal System Optimization

This section will identify and describe seal system de-sign optimization activities that will require site char-acterization data. Potential subjects include:

* studies and tests to assist in design concept selection

* development of design requirements

* studies to translate design requirements into specificdesign descriptions

* development tests to demonstrate the feasibility offabrication processes and to help verify the designs.

Note: Although "optimization", as such, might not bean NRC interest, this section actually deals with theoverall seal system design, particularly as it relatesto site-specific features (i.e., as it depends on sitecharacterization data).

NNWSI seal system design topics that will be of par-ticular interest to the NRC seal program reviewer in-clude:

* ramp seal system design* shaft seal system design* borehole seal system design* backfill design* fault seal system design

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At least conceptually, all of these form differentsystems and, hence, need to be addressed separately.Site characterization data required will be the en-vironmental data identified in Section 8.3.3.2. In-cluded, also, will be the "engineering" aspects ofthe seal design (e.g., seal geometry, seal emplace-ment, and sealing of the rock around seals)

Of particular interest to the NRC sealing program re-viewer will be "development tests to demonstratefeasibility of fabrication processes". Topics to beaddressed include

* whether the tests will be full scale

* whether in situ (at depth)

* description of the performance testing proceduresand duration

Section 8.3.3.5 - Seal System Modeling

This section will describe planned modeling and codedevelopment studies associated with seal system devel-opment, utilization, verification, and validation forthose tests and studies requiring data from site char-acterization.

Note: In principle, this could be an extremely broadaspect of the program-in essence, a miniature versionof the repository modeling program. Examples include

* thermodynamic (geochemical) modeling of long-termseal behavior (component changes, consequences forcomponent/hydraulic conductivity, strength)

* flow modeling

* mechanical interaction modeling

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Many of the NRC sealing program reviewer concernswill be identical to overall program review concerns

e.g., "validation" in the traditional sense is ex-ceedingly difficult and probably impossible for verylong term. Presumably, much of the modeling will beperformed with codes developed for other purpose.If so, the review will benefit from multidisciplinaryreview.

REFERENCES

Fernandez, 1985

Fernandez and Freshley, 1984

U.S. Nuclear Regulatory Commission, 1983

U.S. Nuclear Regulatory Commission, 1985

Vieth et al, 1985