ML20137L213

Discusses Review of 851209 Request for SRP Deviation from Postulating Pipe Break in RHR HX Cubicles.Request for Deviation Granted.Amend to FSAR Section 3.6.2 Requested

ML20137L213
Person / Time
Site:	Clinton
Issue date:	01/07/1986
From:	Butler W Office of Nuclear Reactor Regulation
To:	Spangenberg F ILLINOIS POWER CO.
References
NUDOCS 8601270336
Download: ML20137L213 (4)

Text

-

.a

[

3i-b t,

UNITED STATES j J !ZL NUCLEAR REGULATORY COMMISSION j WASHINGTON, D. C. 20555 o

j JM 0 .-< co Docket No. 50-461 Mr. Frank A. Spangenberg Manager - Licensing and Safety Clinton Power Station P.O. Box 306 -

Mail Code V920 Clinton, Illinois 61727

SUBJECT:

CLINTON POWER STATION - STANDARD REVIEW PLAN DEVIATION FROM POSTULATING PIPE BREAK IN RHR HEAT EXCHANGER CUBICLES The staff has reviewed your submittal, dated December 9, 1985, requesting NRC approval of a plant specific deviation from the Standard Review Plan. The proposed deviation is to not postulate a break at a specific location on the

, Residual Heat Removal (RHR) system piping in each of the RHR heat exchanger

, cubicles. Based on its review, the staff has determined your request for the

deviation at this specific location is reasonable and can be granted as discussed j below.

l At the RHR piping penetration location in the wall which separates the Auxiliary e Building main steam tunnel from the RHR heat exchanger cubicle, an anchor plate i is attached to the steam tunnel side. There are welds on either side of this i anchor plate wh>.h attach the RHR piping to the plate. The partial penetration

weldment of 'ne RHR pipe to anchor plate on the RHR heat exchanger cubicle side

of the anchoi plate is not included in the Inservice Inspection (ISI) program 2

because of inaccessibility. However, the partial penetration weldment on the other (steam tunnel) side is accessible and is in the ISI program. The location

,! of these welds is considered to be a terminal end of the piping and, in accordance l.

j!

with the guidelines of Standard Review Plan 3.6.2, a break should be postulated at this location.

At Clinton, the steam tunnel side has been designed to withstand the jet impinge-i ment, pipe whip and environmental effects of this break. The RHR heat exchanger -

3 cubicle has been designed to withstand the jet impingement and pipe whip effects

of the same break. However, the flooding effects of this break in one cubicle, l combined with a single active failure in the other cubicle would result in the loss of both RHR loops; this necessitates the request for a deviation from the

! requirement to consider the flooding effects of this break in each cubicle.

. This request is based on the assumption that this break is unlikely to occur because of the following provisions in the design:

,, 1. The pipe stresses in the RHR piping at the anchor plates in the steam tunnel wall are approximately 50% of the code allowable

i. stresses.

f l A l _

2. The RHR piping in the areas under discussion are stagnant lines under normal plant operating conditions; therefore no flow induced vibration is expected here and also no rapid ter:perature change is expected during nornal plant operations.

3. There are two independent types of leak detection instrumentation that can alert the control room operator if there is a pipe crack in the RHR heat exchanger cubicles as described in FSAR Section 7.6.1.4.3.4. Therefore, in the unlikely event of a pipe crack, the operator could initiate corrective action to minimize the effects of this event.

4. Because of the design details of this anchor plate to piping welc' ment, a failure of the piping pressure bounaary is unlikely to occur if the partial penetration weld should fail.

Based on the considerations discussed above, the staff concludes that reasonable assurance has been provided that a pipe break at the location identified is not likely to occur. Thus the staff has determined that granting a Standard Review Plan deviation from postulating a break in each cubicle is acceptable.

In response to staff concerns relative to postulating a break at the branch j connection of the RHR system to the feedwater system, you t'.ated that this area has been designed to withstand the effects of jet impingement and pipe whip as well as environmental effects of the break, thus eliminating this as a concern.

! It is requested that you provide an amendment to FSAR Section 3.6.2 to be consistent with applicable portions of your December 9, 1985 letter and the

! staff's approval of your request. If you have any questions related to this

issue please contact the staff's project manager for your application.

f Sincerely, Walter R. Butler, Director BWR Project Directorate No. 4 Division of BWR Licensing cc: See next page i

4

~

4 fir. Frank A. Spangenberg Clinton Power Station Illinois Power Company Unit 1 cc:

Mark Jason Jean Foy, Esquire Assistant Attorney General 511 W. Nevada Public Utilities Division Urbana, Illinois 61801 Office of the Attorney General State of Illinois Center Richard B. Hubbard 100 West Randolph Street - 12th Floor Vice President Chicago, Illinois 60601 Technical Associates 1723 Hamilton Avenue - Suite K Mr. D. P. Hall San Jose, California 95125 Vice President Clinton Power Station P. O. Box 678 Clinton, Illinois, 61727 Mr. D. C. Shelton Manager-Nuclear Station Engineering Dpt.

Clinton Power Station l P. 0. Box 678 Clinton, Illinois 61727 i Sheldon Zabel, Esquire j Schiff, Hardin & Waite 7200 Sears Tower 233 Wacker Drive Chicago, Illinois 60606 Resident Inspector 4 U. S. Nuclear Regulatory Commission -

RR 3, Box 229 A Clinton, Illinois 61727 Mr. R. C. Heider Project Manager

Sargent & Lundy Engineers

! 55 East Monroe Street i Chicago, Illinois 60603 i Mr. L. Larson

.i Project Manager General Electric Company 1 175 Curtner Avenue, N/C 395 i San Jose, California 95125 l

Regional Administrator, Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 1

I I

~

v

. s

2. The RHR piping in the areas under discussicn are stagnant lines under normal plant operating conditions; therefore no flow induced vibration is expected here and also no rapid temperature change is expected during normal plant operaticrs.

3. Therc are two independent types of leak detection instrumentation that can alert the control room operator if there is a pipe crack in the RHR heat exchanger ctbicles as described in FSAR Section 7.6.1.4.3.4 Therefore, in the unlikely event of a pipe crack, the operator could initiate corrective action to minimize the effects of this event.

4. Because of the design details of this anchor plate to piping weldment, a failure of the piping pressure bcundary is unlikely to occur if the partial peretration weld should fail.

Based on the considerations discussed above, the staff concludes that reasonable assurance has been provided that a pipe break at the location identified is not likely to occur. Thus the staff has determined that granting a Standard Review Plan deviation frem postulating a break in each cubicle is acceptable.

In response to staff concerns relative to postulating a break at the branch connection of the RHR system to the feeduater system, you stated that this area has been designed to withstand the effects of jet impingement and pipe whip as well as environmental effects of the break, thus eliminating this as a concern.

It is requested that you provide an amendment to FSAR Section 3.6.2 to be consistent with applicable portions of your December 9,1985 letter and the staff's approval of your request. If you have any questicns related to this issue please ccntact the staff's project nanager for ycur application.

Sincerely, Original 1: anal by Walter k. Butler, Director BWR Project Directorate No. 4 Division of BUR Licensing cc: See next page DISTRIEUTION Docket File RE PDR Local PDR PD#4 Peading RBernero Goddard ,0 ELD EJorcan Bdrires JPartlow BSiegel EHylten BLiaw RPichutani PD#4/PM) / PD#4/D -

JBrarrer dP11b WButler BSieij/86' 01/ /86 01/f/