Regulatory Guide 3.40

Rev. 1, Design Basis Floods for Fuel Reprocessing Plants and for Plutonium Processing and Fuel Fabrication Plants

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Issue date:	12/31/1977
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Revision 1 U.S. NUCLEAR REGULATORY COMMISSION December 1977 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

signed to withstand the effects of floods or discuss the design requirements for flood protection.

Paragraph (a)(1) of §50.34, "Contents of Applica ANSI N170-1976, "Standards for Determining *

tions: Technical Information," of 10 CFR Part 50, Design Basis Flooding at Power Reactor Sites,"'

"Licensing of Production and Utilization Facilities," presents standards to establish design basis flooding requires, among other things, that each application for safety-related features at power reactor sites.

for a construction permit for a production or utiliza ANSI N170-1976 also contains, among other things, tion facility, including fuel reprocessing plants,. in methodology for estimating probable maximum surges clude a description and safety assessment of the site and seiches at estuaries and coastal areas on oceans on which the facility is to be located, with appro and large lakes. Appendix B to Regulatory Guide priate attention to features affecting facility design. 1.59, "Design Basis Floods for Nuclear Power Paragraph 70.22 (f) of 10 CFR Part 70, "Special Nu Plants," gives timesaving alternative methods of es clear Material," requires that each application for a timating the probable maximum flood along streams.

license to possess and use special nuclear material in Appendix C to Regulatory Guide 1.59 gives a a plutonium processing and fuel fabrication plant. con simplified method of estimating probable maximum tain, among other things, a description and safety as surges on the Atlantic and Gulf Coasts. It is the'con sessment of the design bases of the principal struc sensus of the NRC staff that ANSI N170-1976 and ture, systems, and components of the plant, including Appendices B and C to Regulatory Guide 1.59 are provisions for protection against natural phenomena. also applicable to nuclear facilities, and therefore Paragraph 70.23 (b) of 10 CFR Part 70 provides that they are referenced in this guide.

the Commission will approve construction of the The methods described in this guide result from re principal structures, systems, and components of a view of and action on specific cases, and as such, plutonium processing and fuel fabrication plant when reflect the latest general approaches to the problem it has determined, among other things, that the design that are acceptable to the NRC staff. If an applicant bases of the principal structures, systems, and com desires to employ new information that may be de ponents provide reasonable assurance of protection veloped or to use an alternative method, the NRC

against natural phenomena and the consequences of staff will review the proposal and approve its use, if potential accidents. found acceptable.

This guide describes methods of determining the The flood analysis described in this guide need not design basis floods that fuel reprocessing plants and be considered by applicants in their submittals in plutonium processing and fuel fabrication plants t connection with applications for special nuclear ma should be designed to withstand without loss of terial licenses, operating licenses, or construction safety-related functions. It does not identify struc permits for nuclear facilities located at sites above the tures, systems, and components that should be de design basis flood level where it can be demonstrated

• Lines indicate substantive changes from the previous issue.

'The term "nuclear facility" will be used in this guide to

'Copies of ANSI N170-1976 may be purchased from the refer to fuel reprocessing plants and to plutonium processing and American Nuclear Society, 555 N. Kensington Avenue, La fuel fabrication plants. Grange Park, IL 60525.

USNRC REGULATORY GUIDES Comments Should be sent to the Secretary of the Commission, US. Nuclear Regu Regulatory Guides are issued to describe and make available to the public methods latory Commission, Washington. D.C. 20555. Attention Docketing and Service Branch.

acceptable to the NRC staff of implementing specific parts of the Commission's regulations. to delineate techniques used by the staff in evaluating specific problems The guides are issued in the following ten broad divisions or postulated accidents, or to provide guidance to applicants. Regulatory Guides are not substitutes for regulations, and compliance with them is not required. 1. Power Reactors 6. Products Methods and solutions different from those set out in the guides will be accept. 2. Research and Test Reactors 7. Transportation able if they provide a basis for the findings requisite to the issuance or continuance 3. Fuels and Materials Facilities 8. Occupational Health of a permit or license by the Comminsion. 4. Environmental and Siting

9. Antitrust Review

5. Materials and Plant Protection 10. General Comments and suggestions for improvements in these guides are encouraged at all Requests for single copies of issued guides (which may be reoroduced) or for plac.

times, and guides will be revised, as appropriate, to accommodate comments and ment on an automatic distribution list for single copies of future guides in spicilif to reflect new information or experience. This guide was revised as a result of divisions should be made in writing to the US Nuclear Regul~atory Commissioii substantive comments received from the public and additional staff review. Washington, D.C 20555, Attentioin Director, Division of Document Coitrol

that safety-related structures, systems, and compo mically induced floods reasonably possible should be nents are not affected by flooding. considered for each site. Along streams and estuaries, seismically induced floods may be produced by dam

B. DISCUSSION

failures or landslides. Along lakeshores, coastlines, and estuaries, seismically induced or tsunami-type Nuclear facilities should be designed to prevent a flooding should be considered. Consideration of release of radioactivity resulting from the effects of seismically induced floods should include the same the most severe flood conditions that can reasonably range of seismic events as is postulated for the design be predicted to occur at a site as a result of severe of the nuclear facility. For instance, the analysis of hydrometeorological conditions, seismic activity, or floods caused by dam failures, landslides, or tsunami both. requires consideration of seismic events equivalent in The Corps of Engineers for many years has studied severity to the Safe Shutdown Earthquake 4 occurring conditions and circumstances relating to floods and at the location that would produce the worst such flood control. As a result of these studies, it has de flood at the nuclear facility site.

veloped a definition for a Probable Maximum Flood In the case of seismically induced floods along riv (PMF) 3 and attendant analytical techniques for es ers, lakes, and estuaries that may be produced by timating, with an acceptable degree of conservatism, events less severe than a Safe Shutdown Earthquake, flood levels on streams resulting from hy consideration should be given to the coincident oc drometeorological conditions. An acceptable degree currence of floods due to severe hydrometeorological of conservatism, for estimating seismically induced conditions. This combination of events, however, flood levels and for evaluating the effects of the in should be considered only where the effects on the itiating event, is provided in Appendix A, "Seismic nuclear facility are worse than and the probability of and Geologic Siting Criteria for Nuclear Power such combined events may be greater than an indi Plants," to 10 CFR Part 100, "Reactor Site vidual occurrence of the most severe event of either Criteria.'" type. ANSI N170-1976 contains combinations of The conditions resulting from the worst site-related such events acceptable to the NRC staff. For the spe flood probable at the nuclear facility (e.g., PMF, cific case of seismically induced floods due to dam seismically induced flood, seiche, surge, severe local failures, an evaluation should be made of flood precipitation) with attendant wind-generated wave ac waves that may be caused (1) by domino-type dam tivity constitute the design basis flood conditions that failures triggered by a seismically induced failure of safety-related structures, systems, and components, a critically located dam and (2) by multiple dam fail whose failure during such conditions would constitute ures in a region where dams may be located close a threat to the public health and safety, should be de enough together that a single seismic event can cause signed to withstand and remain functional. multiple failures.

For sites along streams, the PMF generally pro Each of the severe flood types discussed above vides the design basis flood. For sites along lakes or should represent the upper limit of all potential seashores, a flood condition of comparable severity phenomenologically caused flood combinations con could be produced by the most severe combination of sidered reasonably possible. Analytical techniques hydrometeorological parameters reasonably possi are available and should generally be used for predic ble, such as may be produced by a Probable tion at individual sites. Those techniques applicable Maximum Hurricane (Refs. 1, 2) or by a Probable to PMF and seismically induced flood estimates on Maximum Seiche. On estuaries, a Probable streams are presented in ANSI N170-1976 and Ap Maximum River Flood, a Probable Maximum Surge, pendix B to Regulatory Guide 1.59. For sites on a Probable Maximum Seiche, or a reasonable combi coasts, estuaries, and large lakes, techniques are pre nation of less severe phenomenologically caused sented in ANSI N170-1976 and in Appendix C to flooding events should be considered in arriving at Regulatory Guide 1.59.

design basis flood conditions comparable in fre Analyses of only the most severe flood conditions quency of occurrence with a PMF on streams. may not indicate potential threats to safety-related In addition to floods produced by severe hy systems that might result from combinations of flood drometeorological conditions, the most severe seis conditions thought to be less severe. Therefore, rea sonable combinations of less-severe flood conditions

3 The Corps of Engineers' Probable Maximum Flood definition should also be considered to the extent needed for a appears inr many publications of that agency such as Engineering consistent level of conservatism. Such combinations Circular EC 1110-2-27, Change 1, "Engineering and Design should be evaluated in cases where the probability of Policies and Procedures Pertaining to Determination of Spillway their existing at the same time and having significant Capacities and Freeboard Allowances for Dams," February 19, consequences is at least comparable to that associated

1968. The Probable Maximum Flood is also directly analogous to the Corps of Engineers' "Spillway Design Flood" as used for with the most severe hydrometeorological or seismi dams whose failures would result in a significant loss of life and property. A similar definition for Probable Maximum Flood is 'Determined as outlined for nuclear power plants in Appendix given in ANSI N170-1976. A to 10 CFR Part 100.

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cally induced flood. For example, a failure of rela wind-generated wave activity constitute the design tively high levees adjacent to a nuclear facility could basis flood conditions that structures, systems, and occur during floods less severe than the worst site components important to safety must be designed to related flood but would produce conditions more se withstand without impairing their capability to per vere than those that would result during a greater form safety functions.

flood (where a levee failure elsewhere would produce a. The standards for determining design basis less severe conditions at the nuclear facility site). flooding at power reactor sites contained in ANSI

Wind-generated wave activity may produce severe N170-1976 are considered by the NRC staff to be flood-induced static and dynamic conditions either generally acceptable for nuclear facilities, subject to independent of or coincident with severe hy the following:

drometeorological or seismic flood-producing (1) Footnote 1 and the list of safety-related mechanisms. For example, along a lake, reservoir, structures, systems, and components in Section 3.1.3 river, or seashore, reasonably severe wave action of ANSI N170-1976 are not applicable to nuclear should be considered coincident with the probable facilities. A list of pertinent elevations of safety maximum water level conditions. 5 The coincidence related structures should be provided for comparison of wave activity with probable maximum water level with design basis flood levels. It should be referenced conditions should take into account the fact that suf to maps and drawings of such facilities.

ficient time can elapse between the occurrence of the (2) Footnote 2 in Section 4.3.1 of ANSI N170

assumed meteorological mechanism and the 1976 is not applicable to nuclear facilities. The words maximum water level to allow subsequent "safe shutdown" in Section 4.3.1 of ANSI N170

meteorological activity to produce substantial wind 1976 should be interpreted to mean "safe curtailment generated waves coincident with the high water level. of operations."

In addition, the most severe wave activity at the'site (3) Sections 5.5.4.2.3 and 5.5.5 of ANSI

that can be generated by distant hydrometeorological N170-1976 contain references to methods for evaluat activity should be considered. For instance, coastal ing the erosion failure of earthfill or rockfill dams locations may be subjected to severe wave action and determining the resulting outflow hydrographs.

caused by a distant storm that, although not as severe The staff has found that some of these methods may as a local storm (e.g., a Probable Maximum Hur not be conservative because they predict slower rates ricane), may produce more severe wave action be of erosion than those that have historically occurred.

cause of a very long wave-generating fetch. The most Modifications to the models may be made to increase severe wave activity at the site that may be generated their conservatism. Such modifications will be re by conditions at a distance from the site should be viewed by the NRC staff on a case-by-case basis.

considered in such cases. In addition, assurance (4) Instead of Section 7.4.5.1 of ANSI

should be provided that safety systems are designed N170-1976, the following should be used:

to withstand the static and dynamic effects resulting

"7.4.5.1 Structure Being Considered. In gen from frequent flood levels (i.e., the maximum operat eral, the structures that need to be considered for ing level in reservoirs and the 10-year flood level in the wave activities are protective dikes, waterfront streams) coincident with the waves that would be produced by the Probable Maximum Gradient Wind" banks and shores, auxiliary and control buildings, for the site (based on a study of historical regional and other safety-related facilities, and non-safety related facilities whose failure could adversely af meteorology). fect safety-related facilities."

(5) The terms "safe shutdown earthquake

C. REGULATORY POSITION

(SSE)" and "operating basis earthquake (OBE)" are used in Section 9.2.1.2 of ANSI N170-197

6. For the

1. The conditions resulting from the worst site purposes of this guide, the safe shutdown earthquake related flood probable at a nuclear facility (e.g.,

(SSE) and the operating basis earthquake (OBE)

PMF, seismically induced flood, hurricane, seiche, should be determined as outlined for nuclear power surge, heavy local precipitation) with attendant plants in Appendix A to 10 CFR Part 100.

'Probable Maximum Water Level is defined by the Corps of (6) Instead of Section 10.1 of ANSI N170

Engineers as "the maximum still water level (i.e., exclusive of 1976, the following should be used:

local coincident wave runup) which can be produced.by the most "10.1 General. Guidance is available if canals, severe combination of hydrometeorological and/or seismic reservoirs, and related structures are used."

parameters reasonably possible for a particular location. Such phenomena are hurricanes, moving squall lines, other cyclonic (7) Instead of Section 10.3 of ANSI N170

meteorological events, tsunami, etc., which, when combined 1976, the following should be used:

with the physical response of a body of water and severe am bient hydrological conditions, would produce a still water level

"10.3 Reservoirs. Guidance is available if a re that has virtually no risk of being exceeded." servoir is used."

'Probable Maximum Gradient Wind is defined as a gradient b. The PMF on streams, as defined in ANSI

wind of designated duration, which there is virtually no risk of N170-1976 and based on the analytical techniques exceeding.

summarized in ANSI N170-1976 and Appendix B to

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Regulatory Guide 1.59, provides an acceptable level components as specified in regulatory position 1 of conservatism for estimating flood levels caused by above, it is permissible to curtail operation of the severe hydrometeorological conditions. facility and initiate suitable protective measures pro c. Along lakeshores, coastlines, and estuaries, vided that:

estimates of flood levels resulting from severe a. Sufficient warning time is shown to be avail surges, seiches, and wave action caused by hy able to curtail operations and implement adequate drometeorological activity should be based on criteria emergency procedures;

comparable in conservatism to those used for PMFs. b. Those structures, systems, and components Criteria and analytical techniques providing this level necessary for confinement of radioactivity during the of conservatism for the analysis of these events are emergency are designed with hardened protective fea summarized in ANSI N170-1976. Appendix C to tures to remain functional while withstanding the en Regulatory Guide 1.59 presents an acceptable method tire range of flood conditions up to and including the for estimating the stillwater level of the Probable worst site-related flood probable (e.g., PMF, seismi Maximum Surge (PMS) from hurricanes at open cally induced flood, hurricane, surge, seiche, heavy coast sites on the Atlantic Ocean and Gulf of Mexico. local precipitation), with coincident wind-generated d. Flood conditions that could be caused by dam wave action as discussed in regulatory position 1 failures from earthquakes should also be considered above.

in establishing the design basis flood. Analytical 3. During the economic life of a nuclear facility, techniques for evaluating the hydrologic effects of unanticipated changes to the site environs that may seismically induced dam failures discussed herein are adversely affect the flood-producing characteristics presented in ANSI N170-1976. Techniques for of the environs are possible. Examples include con evaluating the effects of tsunami will be presented in struction of a dam upstream or downstream of the nu a future appendix to Regulatory Guide 1.59. clear facility, or comparably, construction of a high e. Where upsteam dams or other features that way or railroad bridge and embankment that obstructs provide flood protection are present, in addition to the floodflow of a river, and construction of a harbor the analyses of the most severe floods that may be or deepening of an existing harbor near a coastal or induced by either hydrometeorological or seismic lake site nuclear facility.

mechanisms, reasonable combinations of less-severe Significantly adverse changes in the runoff or other flood conditions and seismic events should also be flood-producing characteristics of the site environs, considered to the extent needed for a consistent level as they affect the design basis flood, should be iden of conservatism. The effect of such combinations on tified and used as the basis to develop or modify the flood conditions at the nuclear facility site should emergency operating procedures, if necessary, to be evaluated in cases where the probability of such mitigate the effects of the increased flood.

combinations occurring at the same time and having 4. Proper utilization of the data and procedures in significant consequences is at least comparable to the Appendices B and C to Regulatory Guide 1.59 will probability associated with the most severe hy result in PMF peak discharges and PMS peak stillwa drometeorological or seismically induced flood. For ter levels that will in many cases be approved by the relatively large streams, examples of acceptable NRC staff with no further verification. The staff will combinations of runoff floods and seismic events that continue to accept for review detailed PMF and PMS

could affect the flood conditions at the nuclear facil analyses that result in less conservative estimates ity are contained in ANSI N170-1976. Less-severe than those obtained by use of Appendices B and C to flood conditions, associated with the above seismic Regulatory Guide 1.59. In addition, previously re events, may be acceptable for small streams that viewed and approved detailed PMF and PMS

exhibit relatively short periods of flooding. analyses will continue to be acceptable even though f. The effects of coincident wind-generated the data and procedures in Appendices B and C to wave activity to the water levels associated with the Regulatory Guide 1.59 result in more conservative worst site-related flood possible (as determined from estimates.

paragraphs a, b, c, d, or e above) should be added to generally define the upper limit of flood potential.

Acceptable procedures are contained in ANSI N 170

D. IMPLEMENTATION

1976.

2. As an alternative to designing hardened protec The purpose of this section is to provide informa tion for all safety-related structures, systems, and tion to applicants regarding the NRC staff's plans for using this regulatory guide.

This guide reflects current NRC staff practice.

'Hardened protection means structural provisions incorpo Therefore, except in those cases in which the appli rated in the nuclear facility design that will protect safety cant proposes an acceptable alternative method for related structures, systems, and components from the static and dynamic effects of floods. In addition, each component of the complying with specified portions of the Commis protection must be passive and in place, as it is to be used for sion's regulations, the methods described herein are flood protection, during normal facility operation. being and will continue to be used in the evaluation

3.40-4

of submittals for operating license or construction REFERENCES

permit applications for fuel reprocessing plants and for license applications submitted pursuant to 10 CFR 1. U.S. Army Coastal Engineering Research Center, Part 70 authorizing possession and use of special nu "Shore Protection Manual," Second Edition, 1975.

clear material at plutonium processing and fuel fabri 2. U.S. Weather Bureau (now U.S. Weather Service, cation plants until this guide is revised as a result of NOAA), "Meteorological Characteristics of the suggestions from the public or additional staff re Probable Maximum Hurricane, Atlantic and Gulf view. Coasts of the United States," Hurricane Research Interim Report, HUR 7-97 and HUR 7-97A, 1968.

3.40-5

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