ML20084K202

AO 50-237/1974-50:on 741004,during Shutdown,Safety Valve 2-203-4E Actuated Low.Caused by Valve Cold Pressure Set Using Nitrogen.Valve Replaced W/Valve Confirmed on Safety Valve Test Facility

ML20084K202
Person / Time
Site:	Dresden
Issue date:	10/10/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084K204	List: ML20084K202 ML20084K210 ML20084K218
References
737-74, NUDOCS 8305190206
Download: ML20084K202 (2)

Text

. _ - _

~~lN Cammo alth Edisin 2,,7 ono r rsi r ni Pi.u.i ch.cago nano s VN/Q Address Remy to: Post Omce Box 7G7 j-; Chicago. I:linois 60690 i BF43 Ltr.#737-74 Drecden Nuclear Power Station j

R. R. #1 lbrris, Illinois 6045 P N October 10, 1974 fdN P M y+v PG\

dT[\N'S,h.y' Mr. James G. Keppler, Regional Director 0 gBM %_)l Directorate of Regulatory Operations-Region III o. C" . ~

U. S. Atomic Energy Cec =1ccion 799 Roosevelt Road s 3 ll, A,j A r lQp/

Glen Ellyn, Illinois 60137 ,

SUBJECT:

REPOR? OF APNORMAL CCCURRE!CE PER SECTIC?! 6.6.A OF THE TFCHIIICAL SFTCIFICATIO:;3.

PRDGTURE ACTUATION OF U:!IT 2 SAFETY VALVC 2-20%4E DURING HYD3OSTATIC TI5T.

References:

1) Regulatory Guide 1.16 Rev.1 Appendix A

2) Notification of Region III of art Regulatory Operatiens Telephone Fr. P. Paura, 1320 heure on October 4, 1974 Telegram: Mr, J. Keppler, 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on October i:, 1974

3) Drawing Number: PelD M-12 Report Number: 50-237/1974-50 Report Date: Oc tober 10, 1974 Occurrence Date: October 4, 1974 Facility: Dresden Nuclear rower Station, F.orrio, Illinois IDS:TIFICATION 09 OCCURRE!CE -

At 0300 hour0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> 0 on October 4, 1974 cafety valve 2-203 4E actuated at 1085 psig pressure which is less than the limit of 1210 i 1% as specified by the Technical Specification 3.

_CO !DITIONS TRICR TO OCCURPS:CE At 0300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> on October 4,1974, Unit 2 vac in the chutde;;n stode.

DESCRIPTION OF Cf'CURRE!CE l

At 0300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> en October 4,197h, a post mainten nce hydrostatic test raa in progreca to ter.t the repair to 21. recire pr.p diccMrge organs piping. f Safety valve 2-203-4E actuated e.t 1C3S poig, which is 1 con than the limit ,$l'N" i p of 1210 1 15 as specified by the Technical Spce2fications, je 8305190206 741010 '

r

{DRADOCK05000 CCT 1 5 .:n W ML MMy 10 0 <. 0

?

. l~- ,

Mr. Jamss G. Kcppler  % tober 10, 1974'. ,

~

DESIGNATION OF APPARETP CAUSE OP OCCID'ta:CE (Component Failure) I The safety valve was tested on October 8,1974 using the safety valve test facility. The pressure setpoint was found to be 1095 poig. The valve had '

been installed in the unit on October 2, 1972 after being pressure set using-nitrogen.

Valves tested during the 1974 refueling outage for Unit 3 have shotm that a valve cold pressure set using nitrogen will often lift at a pressure lower than the extrapolated nitrogen set. This coupled with the long oper-ating time since the safety valve was last tested is believed to be t..e cause of the problem.

A!LEYSIS OF OCCURRD!CE There were no safety consequences to the public or plant personnel as a result of this occurrence because safety valve operability is not required when the reactor is below 320*F. Only minor contamination resulted from the actuaticn and this was contained completely within the drywell. Daring operation, the reactor would be shut down by the high pressure scram before' 1o95 psic would be reached and the only consequences would be contamination released to the drywell.

\ .,

COT 1ECTIVE ACTIg Safety valve 2-203-4E was removed and replaced with a valve that had been '

set 1210 + 1% and confirmed on the safety valve test facility. In addition 7 . '

to this, all rem'ining safety valves will be teated on the safety valve -

test facility during the next refueling outage scheduled to begin in Novcmber 1974.

FAILIGE DATA . -

Premature actuation of safety valves during operation has occurred 3 times in the past. The valves lifted in conjuncticn with a relief valve opening.

The shock wave associated with the relief valve opening is thought to be partially renponsible for the safety valve actuation. Premature actuation is believed to be the result of both the relief valve shock wavo and the use of the nitrogen cold set.

Valve Data '

15G Drcasar Typo 6"-3777QA-HT-21 Sico 6" /

r Sincerely, j A jh/ m- l

/ ^ B. B. Stephenson Supcrintendent FES:do t

______