ML20207H502

Supports Use of Energy Absorbers in Lieu of Snubbers to Provide Support for Nuclear Piping Sys from Effects of Earthquakes & Other Dynamic Loads Described in Util

ML20207H502
Person / Time
Site:	Point Beach
Issue date:	07/15/1986
From:	Colburn T Office of Nuclear Reactor Regulation
To:	Fay C WISCONSIN ELECTRIC POWER CO.
References
NUDOCS 8607240344
Download: ML20207H502 (4)

Text

_

. JUL 151986 Docket Nos. 50-266/50-301 Mr. C. W. Fay, Vice President Nuclear Power Department Wisconsin Electric Power Company 231 W. Michigan Street, Room 308 Milwaukee, Wisconsin 53201

SUBJECT:

USE OF ENERGY ABSORBERS AS REPLACEMENT FOR SNUBBERS AT THE P0 INT BEACH NUCLEAR POWER PLANT By letter dated May 13, 1986 you provided the staff information concerning the use of energy absorbers in lieu of snubbers as providing support for nuclear piping systems from the effects of earthquakes and other dynamic loads. You further indicated your intention to install energy absorbers in place of snubbers in selected locations at the Point Beach Nuclear Plant for Units 1 and 2 under the provisions of 10 CFR 50.59. We wish to make the following comments based upon a limited review of the technical bases for the use of energy absorbers as snubber replacements provided in your May 13, 1986 letter.

1. Elimination of snubbers and replacement with energy absorbers would involve a change in the Technical Specifications in the cpinion of the NRC staff.

2. The number and location of the energy absorbers in a given piping system would be determined by the use of a computer program together with the structural hysteretic properties of the absorbers. Neither of these features has been reviewed in detail by the staff and found to be acceptable.

3. The proposed replacement of snubbers with energy absorbers in a prdviously analyzed safety system could result in a potential decrease in the margin of safety. The reanalysis and verification of adequate safety margins concerning snubber replacement represent a potential unreviewed safety question in the opinion of the NRC staff.

8607240344 860715 PDR P

ADOCK 05000266 PDR

/ s Your May 13, 1986 letter also referenced ASME Code Section III, Code Case N-420 as providing construction rules for energy absorbers.

Guidance on the use of ASME Code Case N-420 (generic energy absorbers) will be contained in revision 24 to Regulatory Guide 1.84. It will state that Case N-420 is acceptable subject to the following conditions in addition to those conditions specified in the Code Case. Each application desiring to use the Code Case should provide the following information prior to implementing the Case: (1) indication of systems.

in which energy-absorbing supports are to be used; (2) fatigue design; (3) piping system analysis results considering inelastic behavior of supports; and (4) plans for inservice examination of energy absorbers.

The above position is consistent with the staff position for the use of energy absorbers on other nuclear power plants.

If you have any questions, please contact me at (301) 492-9787.

Sincerely, b

Timothy G. Colburn, Project Manager Project Directorate #1 Division of PWR Licensing-A-l 1

• SEE PREVIOUS CONCURRENCE Office: LA/ PAD #1 PM/ PAD #1 PAEB PD/ PAD #1 Surname: PShuttlew6 *TColburn/tg *RBallard GLearly?/g,1 Date: I/N86 07/01/86 07/13/86 07//T/86

Mr. C. W. Fay Point 3each Nuclear Plant Wisconsin Electric Power Company Units 1 and 2 cc:

Mr. Bruce Churchill, Esq.

Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.W.

Washington, DC 20036 Mr. James J. Zach, Manager Point Beach Nuclear Plant' Wisconsin Electric Power Company 6610 Nuclear Road Two Rivers, Wisconsin 54241 Mr. Gordon Blaha Town Chairman Town of Two Creeks Route 3 Two Rivers, Wisconsin 54241 Chairman ,

Public Service Commission of Wisconsin Hills Farms State Office Building Madison, Wisconsin 53702 Regional Administrator, Region III U.S. Nuclear Regulatory Commission Office of Executive Director for Operations 799 Roosevelt Road Glen Ellyn, Illinois 60137 l

l Resident Inspector's Office i U.S. Nuclear Regulatory Commission 6612 Nuclear Road Two Rivers, Wisconsin 54241 i

Distributio_n Copies:

Docket Files NRC PDR Local PDR PAD #1 r/f PAD #1 p/f TNovak, Actg. DD NThompson, DHFT ELD EJcrdan BCrimes JPartlow GLear PShuttleworth TColburn ACRS (10) l l

l l

l

- - _ .