ML19340D604
| ML19340D604 | |
| Person / Time | |
|---|---|
| Issue date: | 12/16/1980 |
| From: | Minogue R, Roberts I NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | |
| References | |
| NUDOCS 8012310387 | |
| Download: ML19340D604 (13) | |
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f.;m) 5 THE USE OF STANDARDS IN SELECTING SITES FOR NUCLEAR POWER PLANTS e
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to This paper describes criteria, guidelines, testing methods and requirements which are broadly termed " standards" used in the identification and evaluation of nuclear power plant sites. Special reference is made to the work of the IAEA NUSS Program because of the progress it has achieved in combining the essence of differing national practices into useful guidance for developing countries. Standards in use in the United States are offered as examples. Similar standards have been developed in many other countries.
The requirement imposed on the location of nuclear power plants by individual countries reflect differing circunstances in matters such as energy, supply, charac-1 teristics of available sites and approach to risk.
Thus they are a component of national policy.
Demographic criteria are a prime exampie. The deteraination of acceptable demographic factors involves a very broad public policy judgment of national energy alternatives and their comparative impact. As regards nuclear safety, the accident risks of nuclear power must be assessed carefully, taking into
~1/ A statement presented to the Delegation.of the Commission of the European Communities to a special 0 ECD-NEA-CSNI meeting concerning the licensing aspects of nuclear power plant siting held in Paris, June 10 - 11, 1980, noted that the site requirement of distance from populations should be optiaized in the light of the options available in each country.
-2/ The U.S. Nuclear Regulatory Commission recently stated (Federal Register Notice dated July,1980) that "The Commission recognizes that siting criteria, in general are matters of national policy as well as national geography and population distribution and that other nations do not have the sa.ne flexibility in siting nuclear facilities as the United States...."
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2-account possible accident scenarios, the release and subsequent dispersion of radio _
active material, ranges of population density and distribution, and possible acilons which may be taken to reduce public risk (for example, requiring special design features, administrative control, special communication systems, or other emergency measures). The objective is to assess risks and the effectiveness of risk reduction measures, and to determine from that assessment the level of residual risk which may be then judged as to its acceptability in comparison with the risk and total costs of energy alternatives.
In view of the foregoing, a country embarking on a nuclear power program should exercise caution in adopting the site standards of another country. However,the process of site selection and evaluation, in which the specific standards are applied, need not be reflective of political decisions and the experience gained in individual countries is widely applicable in all countries. This commonality in the process
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of site identification and evaluation has enabled the IAEA NUSS Program to make exceptionally good progress in the development and publication of safety guides related to siting issues.
THE SITE SELECTION AND EVALUATION PROCESS An important concept which underlies the IAEA NUSS Safety Guides is that the rocess of identifying and evaluating sites proceeds in a step-wise manner through survey, selection and qualification stages, all of which are subject to regulatory oversight. The process begins with a survey of a large region for possible sites based largely on an assessment of data from a preliminary examination of the region (reconnaissance level data).
In this step, a few candidate sites are identified.
These candidate sites are then analyzed in more detail using an expanded information base, and a proposed site is selected for future use. In the final step, the proposed l
. site must be demonstrated to have the characteristics assumed from earlier studies and the site-related design bases of the plant must be verified. As the process proceeds from regional analysis to site qualification, standards with increased definition and detail are required.
The procedure, as described in IAEA Safety Guide 50-SG-S9 " Site Survey for 3
Nuclear Power Plants," enphasizes two basic considerations: sites selected should be among the best that are available, and any characteristics of potential sites that might render those sites unsuitable should be identified by careful, systematic screening. This latter consideration can help to avoid the all too frequent experience of sites which have been selected being later found, after a considerable expenditure of resources, to have characteristics of questionable suitability or which require costly compensating design features.
Site Survey In the initial step of regional analysis, availaole information on certain sites characteristics is used to exclude major areas of the region from further consideration. A region of interest is usually very large; thus a detailed survey is not feasible.
The site characteristics selected from the regional analysis are preferably those for which information is readily available and for which simple f
rejection criteria may be adopted (for example, population density, surface faulting, volcanism and regional seismicity).
It must be noted that certain non-safety related factors (such as cooling water availability and proximity to the
-3/Safety Guide 50-SG-S9 " Site Survey for Nuclear Power Plants" was reviewed oy the Senior Advisory Group during the week of Decencer 9 - 12,1980, and approved for distribution to Member States.
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user s of the electricity to be generated) may be particularly useful in excluding areas from further consideration. Much of the information needed for assessing the characteristics selected for the regional analysis should be already available or easily obtained (such as maps, census data, existing geological data or cursory original survey of the region).
In some cases, it is advisable to begin detailed assessment of certain characteristics early in the ' site survey.
In regions with complex or unusual surface water hydrology or geology or seisaology, for example, it is advisable to initiate detailed investigations during the regional assessment.
These factors will be critically important to any site selected within the region and the sooner the investigations are started, the sooner the acceptability of any site in the region can be demonstrated.
An important factor in the site-survey process is the proximity of potentially hazardous facilities that could affect the safe operation of a nuclear power plant; for example, industrial installations which manufacture or process toxic, explosive or flammable materials; pipelines or land and water transportation routes conveying hazardous materials, as well as the proximity of airports or special flight zones.
At sane distance from each of these potentially hazardous activities, the risk fraa the activity diminishes to a negligible level that can be safely ignored. This is termed as " Screening Distance Value (See IAEA NUSS Safety Gaide 50-SG-55 " Extreme Man Induced Events in Relation to Nuclear Power Siting"). Within the Screening Distance, design modifications may be required to protect the Nuclear Power Plant (NPP) against the potentially hazardous nearby activity. A complementary approach is to define minimum " standoff" distances. The existence of a man-induced hazard closer than the minimum distance precludes the location of a NPP at the site in question.
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. Site Evaluation This stage of the site selection process involves the study and investigation of one or more preferred sites to demonstrate that they are suitable for the con-struction of a NPP.
The information needed to make the denonstration of suitability is much more detailed than was required at the site survey stage.
Similarly the standards that are applied must be more definitive. The IAEA NUSS Safety Guides on Siting (Table 1) provide valuable guidance with respect to the evaluation of the Table i near here.
impact of potentially damaging external events (such as earthquakes, floods, tsunamis and the proximity of hazardous facilities) and the consequences of any radioactive material s released (atmospheric-and hydrologic transport).
The Safety Guides describe methods for deriving design bases for external events. These events are divided into two categories (1) those events expected to occur one or more times during the lifetime of a NPP and which it must be designed to withstand and to continue operating; and (2) the rare event which represents either j-the physical limit of the phenomena (or an event of low probability) which the NPP must be designed to withstand without large radioactive releases.
In the United States, standards for the evaluation of NPP sites have been developed under the aegis of' the Anerican Nuclear Society and published as consensus standards by the American National Standr
. Institute. These standards are similar,
in many respects, to the standards being produced by the IAEA NUSS Program on an f
international level. Table 2 lists the relevant ANSI /ANS Standards with an indication
TABLE 1
1 IAEA NUCLEAR SAFETY GUIDES SITING i
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SG-S1 - EARTHQUAKES AND ASSOCIATED TOPICS IN RELATION TO NUCLEAR POWER PU NT SITING (PUBLISHED)
SG-S2 - SEISMIC ANALYSIS AND IESTING OF NUCLEAR POWER PLANTS (PUBLISHED)
SG-S3 - ATMOSPHERIC DISPERSION IN NUCLEAR POWER PuNr SITING (PuSLISHED) 1 SG-Sit - SITE SELECTION AND EVALUATION FOR NUCLEAit POWER PLANTS WITH RESPE'CT TO POPULATION DISTRIBUTION (PUBLISHED) 3 SG-SS MAN INDUCED EVENTS RELATED TO NUCLEAR POWER PLANT SITING (PUBLISHED)
SG-S6 - livDROLOGICAL DISPERSION OF RADIOACTIVE MATERIAL IN RELATION TO NUCLEAR POWER PuMT SITING (UNDER DEVELOPMENT)
SG-S7 - NUCLEAR POWER PUNT SITING - HvDROGEOLOGICAL' ASPECTS (UNDER DEVELOPMENT)
SG-S8 - ASEISMIC DESIGN AND ASSOCIATED TOPICS FOR NUCLEAR POWER PLANTS (PLANNED)
SG-S9 - SITE SURVEY FOR NUCLEAR POWER PUNTS (UNDER DEVELOPMENT) 1 SG-SIDA-DETERMINATION OF DESIGN BASIS FLOODS FOR NUCLEAR POWER punts ON RIVER SITES (IN FINAL STAGE Of *[,.fELOPMENT)
SG-S108-DETERMINATION OF DESIGN DASIS FLOODS FOR NUCLEAR POWER PUNTS ON COASTAL SITES (IN FINAL STAGE OF DEVELOPMENT)
SG-Sil - EXTREME METEOROLOGICAL EVENTS FOR NUCLEAR POWER PUNT SITING (IN FINAL STAGE OF DEVELOPMENT)
SG-S11B-DESics BASIS IROPICAL EYCLONE (IN FINAL STAGE OF DEVELOPMENT) 5-A
6-of the status of each.
Table 2 near here.
Site Qualification It is necessary to determine those geotechnical characteristics of the site that could affect the design, performance and safety of the NPP. The investigations produce the information needed to define the overall site characteristics to the degree that is necessary for an understanding of atmospheric, surface and subsurface conditions and for identifying potential geologic earthquake related hazards that may exist at the site.
Investigations for hazards such as faulting, landslides, cavernous rocks, ground subsidence and soil liquefaction are especially important.
Site investigations also provide the information needed to define local foundation and groundwater conditions as well as geotechnical parameters needed for engineering analyses and design of foundations and earthworks. Such parameter s include the bearing capacity of foundation materials, lateral earth pressures affecting walls, the stability of cuts and slopes in soil and rock, the effect of earthquake-induced motions transmitted through underlying deposits on the response of soils and structures (including the potential for inducing liquefaction in soils), and those needed to -
estimate the expected settlement of structures. Geotechnical parameters are also needed for analysis and design of plant area fills, structural fills, backfills, and earth and rockfill dams, dikes and other water retention and flood-protection structures.
Since the level of safety provided by the plant engineering design, as well as the effectiveness of regulatory oversight, are dependent on the accuracy and reliability of the information provided by these site investigations, the use of
TABLE 2 INDUSTRY CONSENSUS STANDARDS-SPONSORED BY AMERICAN NUCLEAR SOCIETY I.
STANDARDS WHICH HAVE BEEN PUBLISHED ANSI /ANS-2.2 EARTHQUAKE INSTRUMENTATION CRITERIA FOR NUCLEAR POWER PLANTS.
ANSI /ANS-2.B STANDARDS FOR DETERMINING DESIGN BASIS FLOODING AT POWER REACTOR SITES.
ANSI /ANS-2.9 STANDARDS FOR EVALUATING GROUNDWATER SUPPLY FOR NUCLEAR POWER SITES.
ANSI /ANS-2.10 GUIDELINES FOR RETRIEVAL, REVIEW, PROCESSING AND EVALUATION OF RECORDS OBTAINED FROM SEISMIC INSTRUMENTATION.
ANSI /ANS-2.11 GUIDELINES FOR EVALUATING SITE-RELATED GE0 TECHNICAL PARAMETERS AT POWER REACTOR SITES.
ANSI /ANS-2.12 GUIDELINES FOR COMBINING NATURAL PHENOMENA AND MANMADE HAZARDS AT POWER REACTOR SITES.
ANSI /ANS-2.13 STANDARDS FOR EVALUATING SURFACE-WATER SUPPLY FOR NUCLEAR POWER PLANTS.
ANSI /ANS-2.17 STANDARDS FOR EVALUATING RADIONUCLIDE TRANSPORT IN GROUNDWATER FOR NUCLEAR POWER SITES.
II.
STANDARDS UNDER DEVELOPMENT ANSI /ANS-2.3
. GUIDELINES FOR DETERMINING TORNADO, HURRICANE AND OTHER EXTREME WIND PARAMETERS AT POWER REACTOR SITES.
ANSI /ANS-2.4 GUIDELINES FOR DETERMINING TSUNAMI CRITERIA FOR POWER REACTOR SITES.
ANSI /ANS-2.5 GUIDELINES FOR DETERMINING METEOROLOGICAL INFORMATION APPROPRIATE FOR A POWER REACTOR SITE.
ANSI /ANS-2.6 GUIDELINES FOR DETERMINING FUTURE AND PRESENT POPULATION DISTRIBUTION AT POWER REACTOR SITES.
ANSI /ANS-2.7 GUIDELINES FOR ASSESSING CAPABILITY FOR SURFACE FAULTING AT POWER REACTOR SITES.
ANSI /ANS-2.15 GUIDELINES FOR ASSESSING ATMOSPHERIC TRANSPORT OF ROUTINE RELEASE OF NUCLEAR REACTOR EFFLUENT.
ANSI /ANS-2.16 GUIDELINES FOR ASSESSING ATMOSPHERIC TRANSPORT OR ACCIDENTAL RELEASE OF NUCLEAR REACTOR EFFLUENT.
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ANSI /ANS-2.19 GUIDELINES FOR EVALUATING SITE RELATED PARAMETERS FOR INDEPENDENT SPENT FUEL STORAGE FACILITIES.
TII.
SUBJECTS BEING CONSIDERED FOR DEVELOPMENT INTO INDUSTRY CONSENSUS STANDARDS ANSI /ANS-2.18 STANDARDS FOR EVALUATING RADIONUCLIDE TRANSPORT IN SURFACE WATER FOR NUCLEAR POWER SITES.
ANSI /ANS-2.20 GEOLOGY, SEISMOLOGY AND SEISMIC CRITERIA.
ANSI /ANS-2.21 ULTIMATE HEAT SINK.
ANSI /ANS_2.22 ENVIRONMENTAL MONITORING.
ANSI /ANS-2.23 POST EARTHQUAKE INSPECTION.
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approved standard methods, procedures, techniques & equipment i s essential. The_
1 standards developed for sampling and testing of foundation materials used in other construction-type activities are also useful for NPP site investigations.
In the United States, s*andards of this type are those published by the haerican Society 4
for Testing Materials.
Table 3 is a representative listing of the standards i
Table 3 near here.
published b'y that organization that are relevant to NPP site investigations.
SUMMARY
There are important differences in the programmatic needs, interests, and capabilities between a country with a fully developed nuclear power program and a developing country that is considering embarking on such a program. These differences make it unwise to assune that the regulatory program in a developing country can i
be a scaled down copy of that in a developed country.
The Safety Guides 07 NPP Siting of the IAEA NUSS Program provide a developing country with the guidance needed to establish a regulatory framework for the selection and evaluation of sites for the NPP's that identify those sites that are among the most desirable that are available. The definition of the measure of site acceptability is considered a matter for determination by individual countries.
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The purpose of Committee 0-13 of the American Society for Testing Materials is the promotion of knowledge, stimulation of research and the development of specifica-tions, and methods of sampling and testing nomenclature and definitions, and recom-mended practices relating to the properties and behavior of soil and rock for engineering purposes. Other committees active in the development of nuclear ASTM are:
C-26 on Nuclear Fuel Cycle 0-33 on Protective Coating and Lining Work for Power Generation Facilities E-10 on Nuclear Technology and Application and Related Standards of other ASTM committees.
Table 3 A Partial 1.isting of ASTM Standards Published for Building Construction D 1194 Soil static plate load, on spread footings, test, D 1883 Soil bearing ratio, laboratory-compacted specimens, test Soil capillary-coisture relations, D 2325 moisture tensions 0.1 to 1 atm (10 to 101 kPa), test D 3152 moisture tensions 1 to 15 atm (101 to 1520 kPa), test 0 425 Soil centrifuge moisture equivalent, test, Soil classification.
D 2487 for engineering purposes.
Soil, cohesionless, D 2049 relative density, test, Soil, cohesive, D 2850 compressive strength, unconsolidated, undrained, in triaxial compression test, D 2166 compressive strength, unconsolidated, undrained, unconfined, test, D 2435 Soil, unconsolidation, one-dimensional, test, Soil, density, in place, D 2937 by drive cylinder method, test, D 2922 by nuclear methods, shallow depth, test D 2167 by rubber-balloon method, test, D 1556 by sand-cone method, test, D 2488 Soil, description and identification, by visual-manual procedure, rec. practice, D 2113 Soil, diamond core drilling for site investigation, Soil, granular, D 2434 permeability, by constant head method, test D 2419 sand equivalent value, rapid field test,
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D 3385 Soil, infiltration rate, with double-ring infiltrometers, field
- test, Soil investigating and sampling D 1452 by auger borings D 420 for engineering purposes, rec. practice, D 423 Soil, liquid limit, test Soil, mechanics, D 653 def. of terms D 3584 indexing papers and reports, rec. practice and thesaurus, 7-A
.a Soil, moisture content.
D 2216 laboratory test, D 3017 in place, by nuclear methods, shallow depth, test, Soil, moisture-penetration resistance relations of fine-grained soil, laboratory-compacted D 1558 specimens, test Soil, moisture-unit weight relations, D 698 laboratory-compacted specimens, using 5.5-lb (2.5-kg) rammer and 12-in. (304.8-mm) drop, test, D 1557 laboratory-compacted specimens, using 10-lb (4.5-kg) rammer and 18-in. (457-mm) drop, test, Soil, particle size analysis, D 1140 material finer than No. 200 (75-m) sieve, D 422 test Soil, penetration resistance, D 3441 by cone and friction-cone penetrometers, test, D 1586 by split-barrel sampler and hammer blows, test 0 424 Soil, plastic limit and plasticity index, test, Soil, resistance (R)-value and expansion pressure, D 2844 laboratory-compacted specimens, test, Soil, sample preparation for particle size analysis and soil constants testing, D 421 dry D 2117
- wet, Soil, sampling, D 350 ring-lined barrel, D 1587 thin-walled tube, Soil, shear strength, consolidated, drained, in direct, D 3080 shear, test, D 427 Shrinkage factors, test D 854 Soil, specific gravity, by pycnometer, test, 7-B I
_3-The site selection and evaluation process described in the IAEA NUSS Safety Guide 50-SG-59 " Site Survey for Nuclear Power Plants" consists of a deliberate step wise process of site survey and selection which is subject to regulatory oversight.
Increasingly specific standards are applied to each of the stages of site selection.
These Safety guides provide the rationale and technical bases underlying Mencer State practices in a manner that allows a developing country to develop site standards that reflect its own interests and needs, but which are still consistent with the practices of other countries. In that regard, the Safety Guides are remarkably international in their applicability.