Regulatory Guide 3.40

Design Basis Floods for Fuel Reprocessing Plants and for Plutonium Processing and Fuel Fabrication Plants

ML13350A250
Person / Time
Issue date:	11/30/1976
From:	Office of Nuclear Regulatory Research
To:
References
RG-3.040
Download: ML13350A250 (5)

U.S. NUCLEAR REGULATORY COMMISSION November 1976 .

REGULATORY GUIDE

OFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 3.40

DESIGN BASIS FLOODS FOR FUEL REPROCESSING PLANTS AND FOR

PLUTONIUM PROCESSING AND FUEL FABRICATION PLANTS

A. INTRODUCTION

safety-related functions. It do s.:i'ot identify struc- tures. systems, and comp.onei1ts"i*that should be Paragraph (a)(1) of §50.34, "Contents of applica- designed to withstand the dffects of floods or discuss tions: Technical information," of 10 CFR Part 50, the design requirementslfor flood protection.

"Licensing of Production and Utilization Facilities,"

requires, among other things, that each application for a construction permit for a production or utiliza- The methodsý'described in this guide result from tion facility, including fuel reprocessing plants, in- review and action'on a number of specific cases, and clude a description and safety assessment of the site as such, relflectthe latesi general approaches to the on which the facility is to be located, with ap- problem-NkC has approved. If an applicant desires propriate attention to features affecting facility to emniynCwinr.rmation that may be developed in design. Paragraph 70.22(0 of 10 CFR Part 70, *bjutut*.o-to use an alternative metho

d. NRC will

"Special Nuclear Material," requires that each ap- .. i the'lroposal and approve its use, if found ac- plication for a license to possess and use special-'-i cP1 I..

nuclear material in a plutonium processing and fuel -.. .".'>.

fabrication plant contain, among other th * The flood analysis described in this guide need not descrpton of the principal anddescipton safety sfet assessment structure, ndsystems,of.the asessmnt and design

~"omi...ebasei."..

t ;:

r~ oe on er ty be considered apants by applicants m their in m nrssubmittals nm as for of~t~heprincipalstrc.t u*re,.an com special nuclear material lic,;nses or construction per- of the natural plant, including phenomena.provisions r*Proteto&

against ParagrapI*70.23(b) of -10. mit applications for nuclear facilities located at sites

. . . . . .. .

CFR.Part 70 provesa. the C ) , :o" p-- above the design basis flood level where it is obvious Pro c on ion of the ,,-#il that safety-related structures, systems. and compo- prove construction of the principay,*ttuctures, nents are not affected by flooding.

systems, and components of a plutonium processing and fuel fabrication p.Owhen it has determined, among other things, at t . dsign bases of the prin-

B. DISCUSSION

cipal structures, s 'sten an omponents provide reasonable as lof-otection against natural Nuclear facilities should be designed to prevent a phenomena a the nsequences of potential acci- release of radioactivity resulting from the effects of dents. the most severe flood conditions that can reasonably be predicted to occur at a site as a result of severe This e describes methods of determining the hydromecteorological conditions, seismic activity, or design ba oods that fuel reprocessing plants and both.

plutonium rocessing and fuel fabrication plants should be designed to withstand without loss of The Corps of Engineers for many years has studied conditions and circumstances relating to floods and The term "nuclear facility" will be used in this guide to refer to fuel reprocessing plants and to plutonium processing and fuel flood control. As a result of these studies, it has fabrication plants. developed a definition for a Probable Maximum USNRC REGULATORY GUIDES Comments should be sent to the Secetarv ol the C.m;-,,t',son,. U S No, leA'

Regulatory Commision. Washlngton. D C 4%65, Attint,, Oo.t.ketanli unid Regulatory Guides are ,ssued to describe and make available to the public Senrice Section methods acceptable to the NRC sIal of fmplementing specific patts of tte Commissions regulations, to delineate techniques used by the stWt in ev.ltu The guides are issued in the following ten broad divistons aling specific problems or postulated accidents or to provide guidaince to appih cant%. RegulatorV Guides ate not substitutes fot regulations. and compl;ince I. Power Reactors 6 PtilIctl%

with them is not required Methods and solutions ditlerent front those set out in 2 Research and Test Reactort 7 Ttnsirtpotatinti the guides will be acceptable if they provtde a basis lo, the findings tequisite to 3 Fuels And Materials Facitities a Uccupationtrl Health the issuence or continuance of a petmit of license by the Commission 4 Environmentatl And Siting 9 Anwtititl Reniny.

Comments and suggestions for improvements in these guides ate encouraged 5 Materials and Plant Protection tO Generteal at all times, usd guides will be revised. as app lopr**,e. to accommodate aom ments and to reflect new information ot experience. However. comments on Copies of published guides may be obtained hv wtiltepi request indicaltin the this guide, it received within about two months atter its issuance. will be par. divisions desired to the U S Nuclear Re*tilatntv Commission. Washington 0 C

ticulatry useful in evaluating the need for an early tevision. 2055. Attention Cirectot. Ottice of Standardt Developtmrent

Flood (PMF)' and attendant analyt'.d techniques In the case of seismically induced floods along for estimating, with an acceptable degree of conser- rivers, lakes, and estuaries which may be produced by vatism, flood levels on streams resulting from events less severe than a Safe Shutdown Earthquake, hydrometeorological conditions. An acceptable consideration should be given to the coincident oc- degree of conservatism, for estimating seismically in- currence of floods due to severe hydrometeorological duced flood levels and for evaluating the effects of the conditions. But this should be considered only where iinitiating event, is provided in Appendix A to 10 the effects on the nuclear facility are worse, and the CFR Part 100. probability of such combined events may be greater, than an individual occurrence of the most severe The conditions resulting from the worst site-related event of either type. For example, a seismically in- flood probable at the nuclear facility (e.g., PMF, duced flood produced by an earthquake equivalent in seismically induced flood, seiche, surge, severe local severity to an Operating Basis Earthquake' coinci- precipitation) with attendant wind-generated wave dent with a runoff-type flood of Standard Project activity constitute the design basis flood conditions Flood' severity may be considered to have approx- that safety-related structures, systems, and compo- imately the same severity as the seismically induced nents, whose failure during such conditions would flood from an earthquake of Safe Shutdown severity constitute a threat to the public health and safety. coincident with about a 25-year flood. For the should be designed to withstand and remain func- specific case of seismically induced floods due to dam tional. failures, an evaluation should be made (a) of flood waves that may be caused by domino-type dam failures triggered by a seismically induced failure of a For sites along streams, the PMF generally critically located dam and (b) of flood waves that provides the design basis flood. For sites along lakes may be caused by multiple dam failures in a region or seashores, a flood condition of comparable where dams may be located close enough together severity could be produced by the most severe com- that a single seismic event can cause multiple failures.

bination of hydrometeorological parameters reasonably possible. such as may be produced by a Each of the severe flood types discussed above Probable Maximum Hurricane (Refs. 1, 2) or by a should represent the upper limit of all potential Probable Maximum Seiche. On estuaries, a Probable phenomenologically caused flood combinations con-

• Maximum River Flood. a Probable Maximum Surge, sidered reasonably possible. Analytical techniques a Probable Maximum Seiche, or a reasonable com- are available and should generally be used for predic- bination of less severe phenomenologically caused tion at individual sites. Those techniques applicable flooding events should be considered in arriving at to PMF and seismically induced flood estimates on design basis flood conditions comparable in fre- streams are presented in Appendices A and B to quency of occurrence with PMF on streams. Regulatory Guide 1.59, "Design Basis Floods for Nuclear Power Plants." Similar appendices for In addition to floods produced by severe coastal, estuary, and Great Lakes sites, reflecting hydrometcorological conditions, the most severe comparable levels of risk, will be issued as they seismically induced floods reasonably possible should become available. Appendix C to Regulatory Guide be considered for each site. Along streams and es- 1.59 contains an acceptable method of estimating tuaries, seismically induced floods may be produced hurricane-induced surge levels on the open coasts of by dam failures or landslides. Along lakeshores, the Gulf of Mexico and the Atlantic Ocean.

coastlines, and estuaries, seismically induced or tsunami-type flooding should be considered. Con- Analyses of only the most severe flood conditions sideration of seismically induced floods should in- may not indicate potential threats to safety-related clude the same range of seismic events as is systems that might result from combinations of flood postulated for the design of the nuclear facility. For conditions thought to be less severe. Therefore.

instance, the analysis of floods caused by dam reasonable combinations of less-severe flood condi- failuies, landslides, or tsunami requires consideration tions should also be considered to the extent needed of seismic events equivalent in severity to the Safe Shutdown Earthquake' occurring at the location that Determined in a manner analogous to tV-'t outlined in Appendix would produce the worst such flood at the nuclear A to 10 CFR Part 100.

facility site. 'The Standard Project Flood (SPF) is the flood resulting from the most severe flood-producing rainfall depth-area-duration

ýCorps of IEngincers' Probable Maximum Flood definition ap- relationship and isohyctal pattern of any storm that is considered pears in many publications of that agency such as Engineering reasonahly characteristic of the region in which the watershed is Circular EC 1110-2-27. Change I. "Engineering and Design- located. If snowmelt may be substantial, appropriate amounts are Policies and Procedures Pertaining to Determination of Spillway included with the Standard Project Storm rainfall. Where floods Capacities zind Freeboard Allowances for Dams." February 19. are predominantly caused by snowmel

t. the SPF is based on

1968. The Probable Naximum Flood is also directly analogous to critical combinations or snow. temperature. and water losses. See the Corps of Engineers "Spillway Design Flood" as used for "'Standard Project Flood Determinations." EM 1110-2-1411.

dams %hose failures would result in a significant loss of life and Corps of Engineers. Department of the Army (revised March property. 1965).

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for a consistent level of conservatism. Such combina-

C. REGULATORY POSITION

tions should be evaluated in cases where the probability of their existing at the same time and hav- 1. The conditions resulting from the worst site- ing significant consequences is at least comparable to related flood probable at a nuclear facility (e.g..

that associated with the most severe PMF. seismically induced flood, hurricane. seiche.

hydrometeorological or seismically induced flood. surge, heavy local precipitation) with attendant wind- For example, a failure of relatively high levees adja- generated wave activity constitute the design basis cent to a nuclear facility could occur during floods flood conditions that structures, systems, and compo- less severe than the worst site-related flood, but nents important to safety must be designed to with- would produce conditions more severe than those stand without impairing their capability to perform that would result during a greater flood (where a safety functions.

levee failure elsewhere would produce less severe con- ditions at the nuclear facility site). a. On streams, the PMF, as defined by the Corps of Engineers and based on the analytical techniques summarized in Appendices A and B of Wind-generated wave activity may produce severe Regulatory Guide 1.59. provides an acceptable level flood-induced static and dynamic conditions either of conservatism for estimating flood levels caused by independent of or coincident with severe severe hydrometeorological conditions.

hydrometeorological or seismic flood-producing mechanisms. For example, along a lake. reservoir. b. Along lakeshores. coastlines, and estuaries.

river, or seashore, reasonably severe wave action estimates of flood levels resulting from severe surges.

should be considered coincident with the probable seiches. and wave action caused ,v maximum water level conditions.' The coincidence of hydrometeorological activity should be based on wave activity with probable maximum water level criteria comparable in conservatism to those used for conditions should take into account the fact that suf- PMFs. Criteria and analytical techniques providing ficient time can elapse between the occurrence of the this level of conservatism for the analysis of these assumed meteorological mechanism and the max- events will be summarized in subsequent appendices imum water level to allow subsequent meteorological to Regulatory Guide 1.59. Appendix C of Regulatory activity to produce substantial wind-generated waves Guide 1.59 presents an acceptable method for es- coincident with the high water level. In addition, the timating the stillwater level of the Probable Max- most severe wave activity at the site that can be imum Surge (PMS) from hurricanes at open-coast generated by distant hydrometeorological activity sites on the Atlantic Ocean and Gulf of Mexico.

should be considered. For instance, coastal locations may be subjected to severe wave action caused by a c. Flood conditions that could. be caused by distant storm that, although not as severe as a local dam failures from earthquakes should also be con- storm (e.g., a Probable Maximum Hurricane). may sidered in establishing the design basis flood. A

produce more severe wave action because of a very simplified analytical technique for evaluating the long wave-generating fetch. The most severe wave ac- hydrologic effects of seismically induced dam failures tivity at.the site that may be generated by conditions discussed herein is presented in Appendix A of at a distance from the site should be considered in Regulatory Guide 1.59. Techniques for evaluating such cases. In addition, assurance should be provided the effects of tsunami will also be presented in a that safety systems are designed to withstand the future appendix to Regulatory Guide 1.59.

static and dynamic effects resulting from frequent flood levels (i.e., the maximum operating level in d. Where upstream dams or other features that reservoirs and the 10-year flood level in streams) provide flood protection are present, in addition to coincident with the waves that would be produced by the analyses of the most severe floods that may be in- the Probable Maximum Gradient Wind' for the site duced by either hydrometeorological or seismic (based on a study of historical regional meteorology). mechanisms, reasonable combinations of less severe flood conditions and seismic events should also be Probable Maximum Water Level is defined by the Corps of considered to the extent needed for a consistent level Engineers as "ithe maximum still water level (i.e.. exclusive of of conservatism. The effect of such combinations on local coincident wave runup) which can be produced by the most severe combination of hydrometeorological and/or seismic the flood conditions at the nuclear facility site should parameters rcasonably possible for a particular location. Such be evaluated in cases where the probability of such phenomena are hurricanes, moving squall lines, other cyclonic combinations occurring at the same time and having meteorological events, tsunami. etc.. which, when combined with significant consequences is at least comparable to the the physical response of a body of water and severe ambient probability associated with the most severe hydrological conditions, would produce a still water level that has virtually no risk of being exceeded.** (See Appendix A to hydrometeorological or seismically induced flood.

Regulatory Guide 1.59). On relatively large streams, examples of acceptable Probable Maximum Gradient Wind is defined as a gradient wind combinations of runoff floods and seismic events that of designated duration, of which ihere is virtually no riskof being could affect the flood conditions at the nuclear exceeded. facility include the Safe Shutdown Earthquake (see

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footnote 3) with the 25-year flood and the Operating floodflow of a river, and construction of a harbor or Basis Earthquake (see footnote 3) with the Standard deepening of an existing harbor near a coastal or lake Project Flood. Less severe flood conditions, as- site nuclear facility.

sociated with the above seismic events, may be accep- table for small streams that exhibit relatively short Significant changes inthe runoff or other flood- periods of flooding. The above combinations of in- producing characteristics of the site environs, as they dependent events are specified here only with respect affect the design basis flood, should be identified and to the determination of the design basis flood level. used as the basis to develop or modify emergency operating procedures, if necessary, to mitigate the ef- e. The effects of coincident wind-generated fects of the increased flood. The following should be wave activity to the water levels associated with the reported!

worst site-related flood possible (as determined from paragraphs a, b, c, or d above) should be added to a. The type of investigation undertaken to iden- generally define the upper limit of flood potential. An tify changed or changing conditions in the site en- acceptable analytical basis for wind-generated wave virons, activity coincident with probable maximum water levels is the assumption of a 40-mph overland wind b. The changed or changing conditions noted from the most critical wind-wave-producing direc- during the investigation, tion. However, if historical windstorm data substan- tiate that the 40-mph event, including wind direction c. The hydrologic engineering bases for es- and speed, is more extreme than has occurred timating the effects of the changed conditions on the regionally, historical data may be used. If the design basis flood, and mechanism producing the maximum water level, such d. Structures, systems, or components impor- as a hurricane, would itself produce higher waves, tant to safety affected by the changed conditions in these higher waves should be used as the design basis. the design basis flood should be identified along with

2. As an alternative to designing hardened protec- modifications to the nuclear facility necessary to af- tion' for all safety-related structures, systems, and ford protection during the increased flood condi- components as specified in Regulatory Position I tions. If emergency operating procedures must be above, it is permissible to curtail operation of the used to mitigate the effects of these new flood condi- facility and initiate suitable protective measures tions, the emergency procedures developed or provided that: modifications to existing procedures should be provided.

a. Sufficient warning time is shown to be 4. Proper utilization of the data and procedures in available to curtail operations and implement ade- Appendices B and C of Regulatory Guide 1.59 will quate emergency procedures: result in PMF peak discharges and PMS peak still- water levels that will in many cases be approved by b. Those structures, systems, and components the NRC staff with no further verification. The staff necessary for confinement of radioactivity during the will continue to accept for review detailed PMF and emergency are designed with hardened protective PMS analyses that result in less conservative es- features to remain functional while withstanding the timates than those obtained by use of Appendices B

entire range of flood conditions up to and including and C of Regulatory Guide 1.59. In addition, the worst site-related flood probable (e.g., PMF, previously reviewed and approved detailed PMF and seismically induced flood, hurricane, surge, seiche, PMS analyses will continue to be acceptable even heavy local precipitation), with coincident wind- though the data and procedures in Appendices B and generated wave action as discussed in Regulatory C of Regulatory Guide 1.59 result in more conser- Position I above. vative estimates.

3. During the economic life of a nuclear facility,

D. IMPLEMENTATION

unanticipated changes to the site environs which may affect the flood-producing characteristics of the en- The purpose of this section is to provide informa- virons are possible. Examples include construction of tion to applicants regarding the NRC staffs plans for a dam upstream or downstream of the nuclear using this regulatory guide.

facility, or comparably, construction of a highway or railroad bridge and embankment that obstructs the Except in those cases in which the applicant proposes to use an acceptable alternative method for Hardened protection means structural provisions incorporated in Reporting should be by special report to the appropriate NRC

the nuclear facility design that will protect safety-related struc- Regional Office and to the Director of the OiTice of Inspection tures, systems, and components from the static and dynamic ef- and Enforcement. Requirement for such reports should be in.

fects of floods, In addition, each component of the protection cluded in the Technical Specifications or in applicable sections of must be passive and in place, as it is to be used for flood protec-

0

the license application unless it can be demonstrated that such tion. during normal facility operation. reports will not be necessary during the life of the nuclear facility.

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complying with specific portions of the Commis- cant wishes to use this regulatory guide in developing sion's regulations. the methods described herein will submittals for an application docketed prior to July be used in the evaluation of submittals for special 15, 1977, the pertinent portions of the application will nuclear material license or construction permit ap- be evaluated on the basis of this guide.

plications docketed after July 15, 1977. If an appli- REFERENCES

1. U.S. Army Coastal Engineering Research Center, 2. U.S. Weather Bureau (now U.S. Weather Servicc,

"Shore Protection Manual," 1973. NOAA), "Meteorological Characteristics of the Probable Maximum Hurricane, Atlantic and Gulf Coasts of the United Stateb." Hurricane Research Interim Report, HUR 7-97 and HUR 7-97A,

1968.

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