Regulatory Guide 1.125

Physical Models for Design and Operation of Hydraulic Structures and Systems for Nuclear Power Plants

ML13350A272
Person / Time
Issue date:	03/31/1977
From:	NRC/OSD
To:
References
RG-1.125
Download: ML13350A272 (3)

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U.S. NUCLEAR REGULATORY COMMISSION

March 1977 REGULATORY GUIDE

OFFICE OF STANDARDS DEVELOPMENT

REGULATORY GUIDE 1.125 PHYSICAL MODELS FOR DESIGN AND OPERATION

OF HYDRAULIC STRUCTURES AND SYSTEMS FOR NUCLEAR

POWER PLANTS

A. INTRODUCTION

Paragraph (a) (3) (ii) of §50.34, "Contents of Ap- plications; Technical Information," of 10 CFR Part 50, "Licensing of Production and Utilization Facilities,"

requires that the Preliminary Safety Analysis Report (PSAR) include information on the design bases of the facility and the relation of the design bases to the principal design criteria.

Paragraph (a) (4) of §50.34 requires, in part, a pre- liminary analysis of the adequacy of structures, systems, and comnonents orovided for the prevention Examples of types of physical modeling studies in- clude, but are not confined to, the following:

I. Intake structures.

2. Discharge structures.

3. Energy dissipation structures.

4. Spillway and tailwater ratings for (dWrs (water- level discharge relations).

5. Release of water resulting from daiii'lures.

6. Wave runup, including ounaAi',effect'

7. Erosion from waves..and,.rtbilaotin therefrom.

8. Erosion and deppo8io'n in.i

• 6trecamiis and other sysems and component prvie for.

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9. Flow pattersand d(pettion of heated or con- taminated effluerit*i i&"recci'6ing water bodies.

10. Heat'Al'sý IK

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receiving water bodies.

This guide describes the desired coordination of an

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r applicant with the NRC staff and the detail and ex eerience of the NRC staff that documentation of data and studies that. an applicant sozpe '

ican6 have not furnished sufficiently should include in the PSAR to support the use of detidic "'i.r'

mation on physical hydraulic model physical hydraulic model testing for predicting per sd*iiA*r the staff to perform an adequate review. In formance of hydraulic structures and systems 4*r t

.so~,-4instances, staff involvement in the early plan- nuclear power plants. The regulatory position of i~is

"T,%ing of a mcdel study would have resulted in savings guide is applicable only to physical mo~elt"Osedlo, gOf both NRC and applicant funds and time in the predict the action or interaction of su .Uce waterV`

review and acceptance of the results.

with features located outside of contaiihtent.1 The recommendations of this guide are not ppo a e to Accordingly, the regulatory position details the internal plant systems or stuctures.

documentation that should be furnished and the type of coordination between the staff and the applicant that should minimize the time necessary for accep-

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,,.tance of the results of model studies.

Physical hydr

1i ml els' te often used to predict The information described in the regulatory posi- prototype o

nce.

hey are particularly useful tion should be incorporated in the PSAR. However, where h a

res and systems are of un- the staff recognizes that it will not always be possible usual de or configuration and hydraulic to incorporate such information in the initial applica- parameters not be adequately evaluated by state- tion for a construction permit since studies of this of-the-art analytical methods. Hydraulic models may type may not be undertaken until after the PSAR is also be used to establish conservative and reasonable submitted. Such information may, therefore, be add- design or operating bases for sites, structures, or ed to the PSAR by amendment, either by reference to systems involving thermal and erosional problems.

separate reports or by insertion into the PSAR.

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C. REGULATORY POSITION

Because all hydraulic design problems cannot be resolved by the mechanics of similitude and because there are limitations to hydraulic modeling.'the NRC

staff should be furnished with certain documentation

• for any structural, thermal, erosional,I or other physicalhydraulic models used by the applicant to es- tablish design or operating base

s. The regulatory

• position contained in this guide applies only to

'physical models used to predict the action or interac- tion of surface waters with features located outside of containment.

Generally, regulatory positions I and 3 describe in- formation that should be furnished prior to actual model testing., and regulatory positions 4 through 6 describe information needed after testing is com- pleted. Additionally, partial test results should be

provided for staff review and acceptance during the

• course of testing to ensure reconsideration of

• parameters whose importance becomes apparent on the basis of partial data collection. After completing the entire study, all the information should be con- solidated either (1) as a separate report with ap-

propriate reference added in the PSAR or (2) for in- sertion into the PSAR.

1. Prior to construction of the model, the appli-

• cant should submit information outlining (a) the

problem to be resolved, (b) reasons for selecting the hydraulic model chosen to resolve the problem, (c)

expected results to be obtained, (d) a detailed descrip- tion of the model, including a description of

.

materials, methods used to measure parameters, scale relations, and other physical characteristics of the model, (e) methods that will be used to analyze the

• data obtained from the model studies, and (0 a schedule of expected tests, proposed completion dates, and estimated dates for submittal of informa-

• tion for NRC staff review.

2. Staff views and recommendations should be solicited prior to model construction and following or coincident with the submittal of the information

listed in regulatory position 1, and arrangements should also be made for appropriate members of the staff to be present periodically during model opera- tion to observe the actual performance of the model.

3. Documentation should be furnished on how the various conditions of geometric, kinematic, dynamic, and thermodynamic.similitude that take into account

.the physical properties and flow state of the fluid (i.e,.

Froude, Reynolds, Euler, Cauchy, Weber, and other related numbers) have been considered. Because-cer- tain forces may act differently in a model than in a prototype, documentation should be provided to justify the neglect of any forces by showing that these forces (a) are of negligible magnitude, (b) compensate for other neglected forces in such a manner that the effects of both are negligible, or (c) are such that their neglect leads to conservative model results and es- tablishmen.t of conservative 'design or operating bases.

Documentation should be furnished on the methods used to satisfy the equations of similitude in the model. The effects of scale distortions on data ob- tained from the model studies should be documented.

Where applicable, model adjustment and verification procedures should be described, and information should be furnished on the validity of the model over a range of likely flow conditions, heat regimes, at- mospheric conditions, and other physical parameters.

Where applicable, it should be demonstrated that the model will simulate known flow conditions; this ver- ification should be provided when historical data are available.

4. Where full-scale structures or systems having characteristics similar to those being modeled exist and information relative to the observed or measured performance of the existingstructures or systems is available, the physical model results should be com- pared with the available information generated by the existing structures. Testing performed on existing full-scale structures or systems and the results of these tests should be described. The applicability of such tests to the problem in question should be documented, and any conclusions derived from the tests should be discussed. If the results of other model tests are used by the applicant, justification for the use of these results and verification of the ability of these other models to reproduce or predict prototype performance should also be provided.

Detailed documentation of data obtained from existing full-scale structures and systems should be provided, including (a) instrumentation used, (b)

description of the data collection network, (c) fre- quency of collection,. (d) methods of collection, and (e) physical parameters existing at the time of collec- tion, such as heat regimes, flow conditions, and at- mospheric conditions.

5. Any changes to the original design of the prototypes as a result of the model test should be dis- cussed. The designs that were modeled and the basis for modifying the design should be documented.

Undesirable flow characteristics or failure modes for the design tested, as well as any oiihcr problems, should be discussed.

-6. Figures. drawings, photographs, and text sub- mitted as documentation for regulatory positions 3,

4, and 5 should be provided in sufficient detail to al- low the staff to evaluate independently the ap- plicability of the model to the design problem in question. (A typical model investigation report as published by the U.S. Army Waterways Experiment Station has been found acceptable in the past.) Bases

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for the interpretation of model results and for any conclusions reached should be provided. In many in- stances, it may be advisable to provide partial test results for review. The models should not be dis- mantled until the staff has reviewed the submittals.

D. IMPLEMENTATION

The purpose of this section is to provide informa- tion to license applicants regarding the NRC staff's plans for implementing this regulatory guide.

Except in those cases in which the applicant proposes an acceptable alternative method for com- plying with specified portions of the Commission's regulations, the method described herein will be used in the evaluation of submittals for construction per- mit applications docketed after November 1, 1977. If an applicant wishes to use this regulatory guide in developing submittals for construction permit ap- plications docketed on or before November 1, 1977, the pertinent portions of the application will be evaluated on the basis of this guide.

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