ML20198J133
| ML20198J133 | |
| Person / Time | |
|---|---|
| Issue date: | 12/31/1985 |
| From: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20198H997 | List: |
| References | |
| REF-WM-1 NUDOCS 8601310208 | |
| Download: ML20198J133 (23) | |
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g GENERIC TECHNICAL POSITION ON IN SITU TESTING OURING SITE CHARACTERIZATION FOR HIGH-LEVEL NUCLEAR WASTE REPOSITORIES Engineering Branch Division of Waste Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commir+1on Washington, DC 20555 December 1985 0601310200 051210 PDR WASTE pon WM-1
TABLE OF CONTENTS Eit!
1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 BACKGROUNO . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4
3 PUBLIC LAW AND REGULATORY F9AMEWORK ............. 2 3.1 Nuclear Waste Policy Act of 1982 ............ 3 3.2 NAC Rules For Otsposal of High-level Radioactive Waste . 3 4 TECHNICAL POSITIONS ..................... 5 5 O!SCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1 General Rationale For In Situ Tests . . . . . . . . . . . 6 5.2 Rationale for In Situ Testing Required of 00E . . . . . . 7 7
5.3 Content of In Situ Test Plan .............. 8 5.4 Description of In Situ Tests .............. 9 5.5 Sufficiency of Testing ................. 11 5.6 Planning and Scheduling cf Testing ........... 12 5.6.1 Amount and Varfety of Tests ........... 12 5.6.2 Scale of Tests . . . . . . . . . . . . . . . . . . 13 5.6.3 Duration of Tests ................ 13 5.1 Special Testing . . . . . . . . . . . . . . . . . . . . . 14 5.8 Presentation and Occumentation of Test Data . . . . . . . 15 6 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7 ;
BIOLIOGRAPHY . . . . . . . . . . . . . . . . , , . . . . . . 16 8 APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
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- l. FIGURES i.
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, 1 Schematic of Site Activities and 18 Testing Milestones '
2 Reduction of Uncertainties About 19 1 Compliance With 10 CFR 60 Performance Requirements l
3 Field Testing (Illustrative) 20 1
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I GENERIC TECHNICAL POSITION ON IN SITU TESTING OURING SITE CHARACTERIZATION i FOR HIGH-LEVEL NUCLEAR WASTE REPOSITORIES
- 1. INTRODUCTION This generic technical position (GTP) is intended to provide guidance to the U.S. Department of Energy (00E) on in situ testing during site characterization. The essential elements of an in situ testing program should address the requirements and performance objectives of U.S. Nuclear Regulatory Commission (NRC) rule Part 60-Oisposal of High-Level Radioactive Wastes in Geologic Repositories (10 CFR Part 60) with respect to a site to be described in a license application.
This GTP covers in situ testing during the site characterization period at the end of which an application is made for a license, followed by construction authorization, construction, the issuance of a license to receive and possess waste, and eventual closure. The progression of site activities and their relationship to milestones are illustrated in Figure 1. Note that in situ testing and site characterization will take place at a minimum of three sites before DOE submits a license appiteation for one site.
The next sections 2 and 3 discuss the background and regalatory framework for in situ testing. Section 4 is a brief statement of the technical position on in situ testing and section 5 is a discussion containing such items as the rationale and description of specific types of testing.
- 2. BACKGROUND Before submitting a license application, the 00E is required by the Nuclear Waste Policy Act of 1982 and by 10 CFR Part 60 to conduct a program of site characterization. The NRC describes site characterization in 10 CFR 60.2 as:
...the program of exploration and research, both in the laboratory and in the field, undertaken to establish the geologic conditions and the ranges of those parameters of a particular site relevant to the procedures under this part.
Site characterization includes borings, surface excavations, excavation of exploratory shafts, limited subsurface lateral excavations and borings, and in situ testing at depth needed to determine the suitability of the site for a geologic repository, but does not include preliminary borings and geophysical testing needed to decide whether site character 12ation should be undertaken.
e In situ testing as discussed in this GTP refers to the conduct of underground tests for site characterization purposes. Types of in situ tests include:
geological geophysical, hydrological, geomechanical, geochemical, and thermal tests. These tests are to be performed from the exploratory shaft (s) and underground openings on surrounding rock and on other materials and components such as the waste package, engineered backfill, linings, and seals. The conditions under which these in situ tests are to be run should represent, as closely as possible, the realistic repository environment (for example, temperature and stresses). The tests performed under such conditions would provide data to assess the suitability of a particular site and a particular geologic medium to host high-level nuclear waste and realistic input parameters for the design of a geologic repository. Thus, in situ testing constitutes one important element of site characterization.
In situ tests can only be conducted for a limited duration compared with the long time span (10,000 years) during which the repository must function to isolate the waste. Analytical, experimental, and numerical models must be used to make predictions far into the future; however, models have their own limitations on applicability and are sensitive to the quality of data used as input. Uncertainties in the prediction process can be reduced by conducting appropriate in situ tests on a representative volume of rock and by using appropriate models to account for possible inherent spatial variations of physical, hydraulic, and chemical properties within the rock formation. For instance, there is deficient understanding of the effects of heat on rock and mineral behavior as well as the induced hydrological and geochemical changes.
By comparing in situ test data with modeling results, models can be validated, thereby reducing uncertainties in the prediction process.
Much of the guidance provided in this GTP is applicable to tests that can be of long duration and, therefore, are likely to provide valuable information beyond the site characterization period. To supplement the data from continuing in
, situ tests, additional tests (perhaps more refined because of the knowledge i
gained from the earlier tests) must be conducted to assess the performance of the repository. Such tests are among those referred to in 10 CFR 60, Subpart F, as " performance Confirmation Tests," and a technical position on such tests will be given in a subsequent GTP. (Appendix)
- 3. PUBLIC LAW AND REGULATORY FRAMEWORK The requirement of conducting in situ tests has been established by the Nuclear Waste Policy Act (NWPA) of 1982 and the NRC rule,10 CFR Part 60. The intent of NWPA and 1C CFR Part 60 is that the in situ testing program should (1) obtain data to assess the suitability of a particular site, (2) provide representative parameters for design of a repository, and (3) help resolve l before the licensing hearing, important issues that will affect the performance l of the repository.
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3.1 Nuclear Waste Policy Act of 1982 NWPA, (Pubite Law 97-425, Section 113(b)1(A)ii), requires 00E to submit a site characterization plan, including a description of onsite testing, which should cover (1) the extent of planned excavations for any onsite testing with radioactive or nonradioactive materials, (2) plans for any investigative activities that may affect the capability of such candidate sites to isolate high-level radioactive waste and spent nuclear fuel, and (3) plans to control any adverse safety-related effects of such site characterization activities.
Section 113(b)1(B) specifies that the relationship between the waste form or packaging and the geologic medium of such site be included in the description to the extent practicable. Section 113(b)1(C) requires a description of the conceptual design that takes into account likely site-specific requirements..
In situ testing will assist in meeting these provisions of the NWpA.
Section 114(a) requires 00E to submit a statement of the basis for the recommendation of the site and a discussion of data obtained in site characterization activities relating to the safety of such sites. In situ test data will form a substantial part of the basis for site approval and construction authorization.
3.2 NRC Rule for Disposal of High-level Radioactive Waste The NRC rule 10 CFR Part 60 requires in situ testing as a part of site characterization. Therefore, the construction of exploratory shafts, the excavation of test facilities, and the performance of in situ tests will precede the license application. The rulel directs DOE to meet the following requirements:
60.10 Site Characterization (b) Unless the Commission determines with respect to the site described in the application that it is not necessary, site characterization shall include a program of in situ exploration and testing at the depths that wastes would be emplaced.
(c).. 00E is also required to conduct a program of site characterization including in situ testing at depth, with respect to alternative sites.
(d)(4) Subsurface exploratory drilling, excavation, and in situ 1 References are to the rule as currently codified. The Commission has stated that it intends to undertake additional rulemaking to deal with any changes in the licensing procedures that may be necessary in light of NWPA (see 48 FR 28195, June 21,1983).
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testing before and during construction shall be planned and coordinated with geologic repository operations area design and construction. ;
60.11 Site Characterization Report 2 (a)...The report shall include:
(6) A description of the site characterization program including:
(i) the extent of planned excavation and plans for in situ testing, 60.21 Content of Application (c)(1)(ti) The assessment shall contain:
(F) An explanation of measures used to support the models used to perform the assessments required in paragraphs (A) through (D).
Analyses and models that will be used to predict future conditions and changes in the geologic setting shall be supported by using an appropriate combination of such methods as field tests, in situ tests, laboratory tests which are representative of field conditions, monitoring data, and natural analog studies.
60.151 Applicability The quality assurance program applies to all systems, structures and components important to safety, to design and characterization of barriers important to waste isolation and to activities related thereto. These activities include: site characterization, facility and equipment construction, facility operation, performance confirmation, permanent closure, and decontamination and dismantling of surface facilities. .
60.152 Implementation 00E shall implement a quality assurance program based on the criteria of Appendix 8 of 10 CFR Part 50 as applicable, and appropriately supplemented by additional criteria as required by $60.151.
2 Referred to as " site characterization plan" in NWPA. 10 CFR Part 60 is currently being revised to conform to the NWPA.
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- 4. TECHNICAL POSITIONS The NRC staff technical positions on in situ testing during site characterization are:
(1) Before submitting a license application, 00E should perform the necessary and sufficient variety and amount of in situ testing to support, if the facts so warrant, a staff position that the requirements for issuance of a construction authorization (10 CFR Part 60.31) have been met.
(2) The in situ testing program should be developed with two major objectives:
(1) characterization of host rock and in situ measurement of its properties prior to construction and waste emplacement; and (ii) determination of response characteristics of the host rock and engineered i components to construction and waste emplacement. '
(3) 00E should present its site specific and design specific in situ test '
plans in the Site Character 1zation Plan (SCP). The topics that the test i plan should explicitly address are listed in Section 5.3, " Content of In Situ Test Plan" in this GTP. ,
(4) Before developing the in situ test plan, DOE should develop a rationale for in situ testing and present this rationale with the test plan in the SCP. The overall goal of the rationale should be to ensure that all important parameters are identified and ranked according to their relative topics importance in supporting 10 CFR Part 60 licensieg findings. The topics that the rationale should explicitly address are listed in Section 5.2, " Rationale for In situ Testing Required of DOE" of this GTP.
(5) For successful site characterization, 00E should integrate the data from '
surface borehole testing and laboratory testing on small-scale samples with the in situ test results.
This technical position is generic and covers in situ testing for all potential 1
repository sites and designs. Because of the dynamic and evolving nature of site investigations, consultation between NRC and 00E must be an cngoing .
process with each step of the testing program building upon previous results.
i The NRC will follow the results of site investigations and provide further guidance to DOE as in situ testing proceeds. This guidance will principally be given through interaction on the SCP and SCP updates as well as periodic meetings, site visits, workshops, and staff technical positions.
- 5. DISCUSSION In situ testing is essential to assess the suitability of a geologic repository site for hosting high-level nuclear waste and to provide realistic input parameters for a repository design. In situ testing is expected to significantly reduce uncertainties regarding the ability of the host rock to provide long-term isolation and containment of the high-level nuclear waste.
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As shown in Figure 2, the uncertainty for compliance with the cerformance requirements of 10 CFR Part 60 is expected to decrease significantly during the site characterization period. The efforts to lessen the uncertainties will continue even after the license application has been submitted.
In situ testing is an important and necessary element of site characterization.
In spite of being the most effective and direct approach to the characterization of the host rock, any in situ testing program will be, of necessity, limited by practical considerations. For example, the lateral extent of underground excavation for in situ testing purposes will be very limited in comparison to the total volume of rock being characterized. The number and duration of tests will also be limited by practical considerations.
However, in the absence of in situ test results, confidence in the predictions based-only on borehole and laboratory testing may be limited. Although in situ testing is necessary, it is not sufficient by itself and requires integration with all other testing.
3.1 General Rationale for In Situ Testing The state of knowledge in the earth sciences is such that in situ testing is necessary to (1) adequately characterize the rock and (2) rationally design the repository. Without creating large-scale openings in the host rock in which direct observations can be made, only very limited statements can be made about actual conditions critical to site suitability and design from surface boreholes. Furthermore, understanding rock behavior under repository conditions is complicated by the interaction of the thermal-hydrological-mechanical-chemical (THMC) effects of waste emplacement. These effects can not be studied and understood by analytical models alone. The in situ tests at the appropriate scala, therefore, provide the best means of directly assessing the characteristics of the host rock.
The following unique features make in situ tests an essential element of site characterization and the rational design of the repository.
(1) Scale Effects Can Be Minimized Numerous laboratory and in situ tests have shown that many of the measured rock properties (for example, compressive strength and permeability) are influenced by the size of the rock specimen tested. In highly jointed rocks, this dependence on size could be more pronounced. In situ tests that measure crucial design parameters clearly minimize the scale effect as a source of error.
(2) The Rock Mass in Its Natural Condition Can Be Observed and Tested.
The natural conditions of the rock mass cannot be exactly duplicated in the laboratory. Examples are (a) geologic discontinuities such as joints and. shear planes, (b) hydrologic conditions such as hydraulic head and l O l
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pore pressure, (c) loading conditions such as the in situ stress field, and (d) temperature. The in situ tests, by definition, encompass the natural rock conditions; therefore, the rock is tested in its natural state.
(3) Coupled / Interactive Processes Can Be Ofrectly Observed Many coupled / interactive processes (for example, hydrothermal, thermomechanical, hydromechanical, and thermochemical) are likely to occur in the host rock in which the nuclear waste will be disposed. In situ tests can measure representative properties resulting from coupled / interactive processes, onlike most small-scale laboratory tests.
Furthermore, the in situ tests, if conducted properly, can prov'de for measuring a possible nonlinear behavior that is difficult to extrapolate fro::: small-scale laboratory experiments.
(4) Host Rock Variability Can Be Evaluated.
Variability in geology (for example, joint patterns and spacing),
hydrology, and geochemistry can only be directly assessed through in situ testing. Estimation of variability and assessment of ability to predict rock behavior in different parts of the repository are necessary for satisfactory design of the repository.
5.2 Rationale for In Situ Testing Required of 00E The in situ testing program'must be site specific to account for: (i) local geologic conditions, (ii) analytical methods and models chosen for use at the site, and (iii)' key issues found relevant to performance of the selected repository design. However, certain features are common to all in situ testing programs and should be addressed explicitly in the rationale as follows:
(1) All relevant issues requiring resolution by in situ testing and measurements; (2) the information needs for the license application (identified on the basis of 10 CFR Part 60 requirements and the level of uncertainty in predicting the performance of the repository);
(3) the availability of existing tests to provide all the information needed; (4) the capabilities and limitations of available tests and measurement methods; (5) the need, if any, to develop new tests; (6) the effects of testing on long term repository performance; (7) the extent of the underground test facility required to assess host rock variability properly and to assess the effect of that variability on design and performance; 7
(8) the extent of the underground facility needed in order to minimize or avoid interference among tests; (9) the sufficiency of subsurface geologic mapping, geophysical testing, and core drilling to assess the characteristics of the host rock and the variability of its properties; (10) the representativeness of the in situ test location compared to the entire volume of rock, that must be assessed in determining compliance with the U.S. Environmental Protection Agency limits for releases to the accessible environment (11) the basis for selection of a particular. Scale and duration of testing; (12) justification for conducting or not conducting coupled / interactive (THMC) tests (13) extant of credit taken for the performance of important components of the barrier system, engineered and natural; (14) the sufficiency (amount, scale and duration) of geological, hydrological, geomechanical, geochemical, thermal, and coupled / interactive testing, to make findings on compliance with the performance objectives on a scale.that is sufficient to realistically represent the inhomogeneities and discontinuities of the rock being tested; and (15) description of the manner in which data from surface borehole testing and laboratory testing on small-scale samples will be integrated with the in situ test results.
All of these aspects should be sufficiently addressed so that findings on the technical criteria and performance objectives of 10 CFR Part 60 can be made at the time of licensing.
5.3 Content of In Situ Test Plan The in situ test plan should identify all important parameters, classify them according to their retative importance, and document their potential variability and its influence on design / performance. The plan should be flexible to accommodate new issues that might develop during site characterization. The in situ test plan should include such components as: the tests to be performed during site characterization needed to characterize the host rock before construction and waste emplacement, and to determine the response of the host rock and engineered components to construction and waste emplacement activities; criteria for determining sufficient number of tests; schedules and duration of various tests and their relationship to site selection, repository design, and licensing schedules; types of analyses to be applied to the test data and the validity of these analytical methods; and the quality assurance programs under which testing and analyses will be conducted.
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5.4 Description of In Situ Tests ,
As a minimum, geological geophysical, hydrological, geomechanical, geochemical, thermal, and THMC tests, as well as tests on seals and backfill materials, should be considered in formulating the in situ test plan. The extent of each type of testing may vary with the individual site, the selected repository design, and the site issues that require resolution by testing. The following is a brief description by discipline of these in situ tests and associated laboratory analyses:
(1) Geological-Geophysical Tests (a) inspection, examination, and geologic mapping of exposed rock in exploratory shafts and accessible underground excavations including characterization of lithology, structural features, and discontinuities intersecting underground openings (b) drilling of horizontal, vertical, or inclined boreholes from within the exploratory shaft (s) and underground excavations to obtain samples for testing (c) lithological logging of cuttings and cores obtained from boreholes, shafts, and underground excavations to characterize lithological variations and discontinuities (d) underground geophysical testing (for example, resistivity and radar) and borehole geophysical testing and measurement techniques (for example, sonic, gamma, and electrical logging; strain meters; vertical seismic prof.iles; borehole gravity and magnetics; and shear wave surveys) to assess the properties and distribution of units and their associated discontinuities (2) Hydrological Tests (a) estimation of the potential for high rates of groundwater influx into the exploratory shaft and underground excavations, which may be obtained by (i) means of pilot holes drilled from the exploratory shaft and underground test facility for detecting the presence of zones of anomalously high hydraulic conductivity in close proximity to the underground test facility or the exploratory shaft (s); (ii) correlation of discontinuities mapped along the drifts with observed zones of groundwater influx and their corresponding calculated flow rates; and (iii) a chamber test for determining groundwater influx potential, if needed (b) monitoring of transient changes in formation pressures in the volume of rock close to the underground workings and evaluation of changes 9
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induced by in situ hydrological and geomechanical tests, subsequent construction activities, and surface-based hydrological testing (c) determination of hydrologic parameters such as directional hydraulic conductivity, total and effective porosity, specific storage, pore water pressure, and degree of saturation; measurement of parameters within the hydrologically significant units overlying and underlying the host rock, if appropriate (d) testing to evaluate the potential significance of fracture flow and matrix diffusion on radienuclide transport (3) Geomechanical Tests (a) representative volume testing (for example, block tests) to predict the constitutive behavior (strength and deformability) and potential failure mechanisms of the host rock (b) where applicable, measurement of the in situ stresses from underground openings so that they can be compared with the stresses measured from the surface boreholes and so that the prevailing stress field around the underground openings can be more accurately estimated (c) demonstration of repository construction (for example, mine-by test),
emplacement, and retrievability, and observation of full-scale response of underground openings and backfill by simulation 3
(4) Geochemical Tests (a) sampling and in situ testing of retardation and migration characteristics of host rock to support labcratory studies of all significant geochemical conditions and phenomena to provide a reliable data base for modeling studies (b) measurement of physical parameters such as ambient temperature and pressure (c) chemical analyses of rock cores to determine the pre-waste emplacement mineralogy and elemental composition of the host rock and surrounding strata 3 The nature of geochemical tests may require certain samples to be transported to a laboratory for testing and analysis.
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(d) chemical analyses of the groundwater, including analyses of the compositions of elements and species, pH, redox conditions, gas components, and organic / colloidal material, to provide an understanding of possible transport mechanisms (e) mineralogical and petrological analyses to determine mineral phases, morphologies, distributions, and textures (f) tracer tests to determine retardation factors and scaling factors for laboratory tests (5) Thermal Loading Tests thermal loading tests (for example, small- and large-scale heated block tests) are to support modeling studies of repository scale temperature effects such as thermal expansion and stability effects, and to establish, by simulation, canister scale behavior; special emphasis on the effects of the thermal field to open or close the existing fractures or initiate new fractures.
(6) Coupled / Interactive Tests the near-field tests designed to simulate the THMC interaction giving rire to processes that may significantly affect repository performance.
(7) Tests on Seals and Backfill Materials appropriate hydrological, geomechanical, geochemical, thermal, and coupled / interaction testin'g of seals and backfill materials, which are ma,jor components of the repository system, to study their effectiveness, durability, and long-term performance; results of these
. tests also to be used in performance confirmation 5.5 Sufficiency of Testing The design of a geologic repository is governed by the 10 CFR Part 60 requirement of a multiple-barrier approach. The amount of testing required for individual components of the barrier system will depend in part on the amount of credit taken for individual components in meeting the performance requirements. This implies that in developing its plans for testing curing the site characterization and engineered component design phases, DOE will identify 11
performance goals for repository system components or, a site-specific basis.
Such identification of performance goals is a necessary prerequisite to establishing what is a necessary and sufficient level of testing. Thus, tentative goals are needed at the time that the Site Characterization Plans are issued. Because of the large uncertainties that would be associated with DOE's understanding of a candidate site at that time, these tentative performance goals necessarily involve making technical and management decisions and should be conservatively chosen. As site characterization proceeds and a more complete understanding of the site is developed, the initial choice may have to be revised and appropriate changes made to the test plan. Given a particular set of performance goals, little or no testing of a certain component of a barrier may be necessary. For example, if no credit is taken for a component and an appropriate level of conservatism is built into the overall system, limited testing of that component may be sufficient.
5.6 Planning and Scheduling of Testing Many phases of in situ testing are required to continue during si~ ting design, construction, and operation stages. Because of the long lead-time of some tests, the schedule of testing will be crucial to the licensing activity. When a construction authorization application is submitted for a particular site, that application must be complete and fully supported by the data and analyses necessary to make a decision on construction authorization findings (10 CFR Part 60.31). DOE, in order to develop a plan and schedule for in situ testing that will provide sufficient information by the time the license application is submitted, should consider the amount and variety, scale, and duration of testing needed, which are dependent upon the amount of credit taken for individual components in meeting the performance requirements of 10 CFR Part 60, as discussed in the previous section. The planning of a testing schedule should also consider-the long lead-times required by some tests in order to develop equipment and procedures.
It is essential that fundamental test results be in place at the time of license application. DOE should identify in its test plan which tests will be completed at the time of the construction authorization application, and which tests and long-term monitoring activities will continue after that.
5.6.1 Amount and Variety of Tests Decisions related to establishing the amount and variety of testing needed should be made on a site- and design-specific basis. This can vary significantly depending on the objective, nature, and scope of the tests and the degree of certainty sought. Several different tests can be used to obtain the same rock parameters. For example, the plate test, pillar test, and block test can each provide sufficient information to calculate the material modulus.
Each test or type of test can be repeated a number of times depending on the required level of confidence. The same test may be repeated at a number of 12
different locations to assess the inherent variability of the measured parameter. Also, it may be desirable to conduct tests under a range of conditions to rapresent the extremes of the anticipated environment. For example, a range of temperatures and confining pressures can be applied to cover the anticipated repository conditions.
The in situ test plan should include criteria to determine whether the amount and variety of testing is sufficient. For all tests important to performance, a general guideline is that testing should continue or be repeated until the results are technically defensible.
5.6.2 Scale of Tests Because of the complexities of designing and constructing an underground repository, testing will have to be performed at different scales. Laboratory testing on small specimens will provide useful information for preliminary designs and analyses. However, in many cases, large-scale testing (also called full-scale testing) will be required to yield a realistic and convincing data base (for a comparative scale of the field tests, see Figure 3). The need for large-scale testing will have to be established on a site- and design-specific basis. The in situ test plan should discuss the scale of testing and its implications for site characterization. Moreover, the underground openings should be of sufficient extent so that the variability in the host rock and adjacent strata can be properly assessed.
5.6.3 Duration of Tests Testing of geologic materials for certain design parameters can be of long duration. However, many design parameters can be obtained by testing over relatively short periods. When the processes being observed are slow, complex interactions are involved, or time effects are important (or predominanti, it is extremely important that tests be of sufficiently long duration so that meaningful and representative data can be obtained. There is particular uncertainty in the testing required to analyze coupled / interactive thermal effects of waste emplacement on the host rock and groundwater. Because of the significant effects on schedules, such long-duration tests need careful planning. As stated in the technical position on developing a rationale, the most important step in planning is to determine what kind of information is required in a license application. Therefore, it is important to identify, before the test is completed, how much of the data from a long-term test can be analyzed and extrapolated into the future. As discussed in Section 5.3, the test plan should discuss how the data from such long-duration tests (if any) will be used in the repository design.
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l 5.7 Special Testing Special tests in this GTP refer to the unconventional or nonstandard tests or both, for instance, accelerated tests to simulate long-term effects in a short-duration test period and tests to assess interactions among different processes, such as THMC effects. These types of tests should be conducted after the proper determination of their appropriateness, adequacy, and procedures. To minimize delays during licensing hearings, a careful and logical approach should be followed in identifying the need for such complex tests and defending the data obtained from them. The test plan should discuss the need for and the rationale behind such complex tests and present details on how the data will be analyzed and used.
As was noted previously, DOE should identify performance goals for repository system components on a site-specific basis. Given a particular set of performance goals, little or no testing of a certain component of a barrier may be necessary.
Because the coupled / interactive processes will take place following waste emplacement, the test plan should either provide for direct testing of the coupled / interactive behavior or demonstrate that such testing is not needed.
The need for coupled / interactive testing should be based on site-specific conditions. The following guidance can be useful in deciding the need for direct testing of coupled / interactive behavior. Coupled / interactive testing may not be needed if the following conditions are met:
(1) In evaluating overall repository performance, no credit is taken for that portion of the rock that cannot be evaluated without direct testing of coupled / interactive effects.
(2) Components of the natural system (that is, geologic, hydrologic, and geochemical) for which performance credit is taken are characterized adequately for evalua. tion of overall repository performance.
(3) Components of the engineered barrier system, such as the waste package, are designed with adequate conservatism with respect to the coupled / interactive behavior that will be encountered. Examples of conservatism in design could include (a) limiting thermal loading and (b) thickening of waste container walls.
(4) The tests that support the design of the engineered barrier system are carried out under a much wider range and more adverse conditions than anticipated. This means that the design of the tests takes into account conditions above and beyond the full range of behavior that is expected to be encountered under a given thermal load.
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If DOE establishes that coupled / interactive testing is not needed on the basis of the above four conditions, then 00E should provide a technical evaluation identifying the volume of rock for which no performance credit is taken. Also, steps should be taken to ensure that the potential for any deleterious effects on the engineered barrier system is effectively accounted for.
. 5.8 Presentation and Documentation of Test Data The presentation of the information obtained from in situ tests is a very important phase of the test program. Both raw and processed data should be documented in a clear and logical manner so that:
(1) the quality of data can be independently checked for precision and accuracy (2) the data are in a form suitable for application in descriptive and predictive models to allow for independent interpretations (3) all measured ranges (if possible, with distributions) of data are clearly presented to allow deterministic as well as probabilistic performance analyses.
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- 6. REFERENCES Code of Federal Regulations, Title 10, Energy (10 CFR Part 60), U.S. Government !
Printing Cffice, Washington, D.C., January 1,1985.
Nuclear Waste Policy Act of 1982, Public Law 97-425, JanJary 7, 1983.
U.S. Nuc. lear Regulatory Commission, " Disposal of High-Level Radioactive Wastes in Geologic Repositories: Technical Criteria", Supplementary Information, 48 F_R 28195, June 21, 1983.
...., NUREG/CR-2983, " Selected Hydrologic and Geochemical Issues in Site Characterization for Nuclear Waste Disposal," Lawrence Berkeley Laboratories, January 1983.
...., NUREG/CR-3065, "In Situ Testing Programs Related to Design and Construction of HLW Deep Geologic Repositories, Task 2," Vols. I and 2, Golder Assoc., March 1983.
- 7. BIBLIOGRAPHY Martin, J. B., U.S. Nuclear Regulatory Commission, letter to Dr. Franklin E, Coffman, Department of Energy, " Comments on the National Waste Terminal Storage Program Strategy," April 15, 1982.
Olson, O. L., U.S. Department of Energy, letter from Basalt Waste Isolation Project Office, WA, to Dr. R. J. Wright, U.S. Nuclear Regulatory Commission,
" Request for Clarification of BWIP SCR," May 11, 1983.
Staff, Basalt Waste Isolation Project, Rockwell Hanford Operation, " Exploratory Shaft Test Plan," S0-BWI-TP-007, November 9, 1983.
U.S. Nuclear Regulatory Commission, " Disposal of High-Level Radioactive Waste in Geologic Repositories: Licensing Procedures," 46 FR 13971, February 25, 1981.
......, NUREG-0960, " Draft Si?.e Characterization Analysis of the Site Characterization Report for the Basalt Waste Isolation Project." March 1983.
......, NUREG/CR-2854, " Evaluation of Alternative Shaft Sinking Techniques for HLW Deep Geologic Repositories," Task 3, Golder Associates, March 1983.
.....,-NUREG/CR-2959, " Relationship Jf an In Situ Test Facility to a Deep Geologic Repository for HLW," Task 4, Golder Associates, March 1983.
Wright, Robert J., U.S. Nuclear Regulatory Commission, " Division of Waste Management Notes on NRC/00E Meeting in Richland, WA," June 9 and 10, 1982.
16
h APPENDIX Type of Testing Three categories of tests may be identified: (1) preliminary testing, (2) site characterization testing, and (3) performance confirmation testing. These tests can deal with observation of (1) host rock characteristics before construction or (2) host rock response after waste emplacement.
(1) Preliminary testing is basically all initial testing done to select a repository site for characterization. These preliminary tests can be of different scales and at any location. The results from such tests could be used for making certajn preliminary assessments about site suitability and performance of the media in general. Preliminary testing is outside the scope of this report and only mentioned here for completeness.
(2) Site characterization testing includes testing and measurements performed to gather necessary and sufficient data to characterize the site and to yield data input for performance assessment. Again, the testing could be of different scales and duration. The in situ testing program falls into this category. Traceability of test data and procedures is very important because the results from in situ tests will be used to support a license application.
(3) Performance confirmation testing may start during site characterization and will continue until permanent closure as required by 10 CFR 60.140(b) and (c). However, some of the performance confirmation tests will be a continuation of the testing started during site characterization as described in (2) above. The data from confirmation tests are crucial to (a) verify assumed design ~ conditions, (b) confirm predicted response characteristics of the repository resulting from construction and waste emplacement, and (c) provide bases for design modification. Performance confirmation tests are not discussed in the GTP; they will be described in 4 subsequent GTP.
The test plan should clearly identify the tests under the above categories and discuss how the data from different categories of tests will be used in reposito.ry design and performance assessment.
17
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