ML20084N975

AO 50-249/1975-30:on 750605,standby Liquid Control Pump Discharge Relief Valves Found at Setpoints Lower than Tech Spec Limits.Caused by Setpoint Drift.Valves Cleaned & Reset

ML20084N975
Person / Time
Site:	Dresden
Issue date:	06/13/1975
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084N979	List: ML20084N975 ML20084N984
References
368-75, NUDOCS 8306090141
Download: ML20084N975 (3)

Text

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/,9h Camn :alth Edicon

' one rir: :onal Pira. Chicago, lilinois A

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@ ,,ss , Address Chicago,11hnois 60690 ,

BBS Ltr. #368-75 Dresden Nuclear Power Station R. R. #1 i Morris, Illinois 60450 7 () ' t 'N.'.h June 13, 1975 fg' s .:,, s

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-: 3g317 E75 s. 1 Mr. Janes G. Keppler, Regional Director O ,' 2 Directorate of Regulatory Operation-Region III ci 'f, U. S. I!uclear Rerulatory Cc=ission 799 Roosevelt Road

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Glen Ellyn, Illinoin 60137

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SUBJECT:

RFPORT OF AF:! C'1L 00CliRR" CE PFR S ETION 6.6.A 0F THE TrCICUCAL SFEC1FIC/. TIC::S SBLC RELIEF VALVE SMFOILPS LESS TAAN TEH SPEC LI!GTS

SUBJECT:

1) Regulatory Guide 1.16 Rev. 1 Appendix A

2) Notification of Region III of U. S. Nuclear Regulatory Comission Telephone: P. Johncon,1500 houro on June 5,1975 Telecra:n: J. Keppler, 1545 hours0.0179 days <br />0.429 hours <br />0.00255 weeks <br />5.878725e-4 months <br /> on June 5, 1975

3) Drawing Number M-354

4) Letter from H. K. Hoyt to Dr. Peter A. Morris; Report No. 50-237/1970-48 Report Number: 50-249/1975-30 Report Date: June 13, 1975 Occurrc'nce Date: June 5, 1975 Facility: Dresden Nuclear Power Station, Morrie, Illinois IDF2,71PICATICN OF OCCimRCCE The Standby Liquid Control (SELC) p=p diecharge relief velves were found at setpointo lower than the Technical Speciff cation liraits.

CONDITIONS PRIOR TO OCCL' RED CE Unit-3 was in the shutdown r. ode for a refueling outacc.

DESCfllI? ION OF OCCURRD:CE On May P.4,1975 a test was perfor:ncd, in the rcaintenance shop, on relief valve 1105-A to detomine the relief valve cetting. The valve was found 'to be act at

.1250 pai.

8306090141 750613 PDR ADOCK 05000249 S PDR -

8533

Mr. Jam p G. Ksppler Junn 13, 1975 1-.

O O The same test was performed on relief valve 1105B on May 28, 1975 At 1320 psi the valve began to leak.

n .These events were reported at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on June 5, 1975 Failure to report the incident it=lediately was a result of a procedural inadequacy which specified that no action be taken.

DESCRIPTION OF APPldlE"T CAUSE OF OCCURRENCE (Equipment Failure)

E Relief valve 1105A performed properly in the test except that the cetpoint was low. This incident is attributed to setpoint drift.

Relief valve 1105 a began to leak at 1320 pci, belou the required cotting . ' '

Dicassembly of the valve revealed crystale of codium penta' borate on the valve seat. These crystals prevented the valve'from ceating properly and lowered its relief setpoint. .

ANALYSIS OF CCCURRI' DOE Both SBLC purpo are 100% capacity pumps. When required, the reactor operator will select one of the systen.s. Therefore, the operability of the cyr.ttm is litaited to 1250 pai. The system is intended as a backup cystem for the control rod drive system, with the reactor in the cold condition, in the event that all rods fail to incert after a reactor trip.

The SBI4 cystem will not be required to operate Eith reactor pressure greater than 1250 poi as there are no expected reactor trcnoients which result in a reactor pressure creater than 1250 psi in the period of time which can affcet the operation of the SELC system. Therefore, the health and safety of the public were not compromised by this occurrenec.

CORRECT.IVE ACTION Valve 1150-B, which startc'd leaking at 1320 psi was cleaned and lapped to remove the cryctals around the valve cent. It uns then roset to 1448 psi and reinstalled on May 30, 1975 Valve 1105-A uas cleaned and reset. This event is considered to be an isolated caso and does not api: car to be an inherent problem in the design of the valvo.

No further action was deemed neccessary.

The procedure for testing the SBI4 injection lines uas reviced prior to the most recent valve test. The valven are nou tested with nitroscn in the raaint-enance shop. This uill miniraize the possibility of codium pentaborate crystals forming on the valve coat. In addition, the relief valvo tocting procedure will be revised by July , 1975 to ensure that any deviation frem Tech Speco limits is reported to the chift ensincer within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the occurrence.

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0,-- Mr. Jamin G Keppler - -

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- FAIIERE DATA ' .

t: A review of station records indicates that sodium pentaborate deposits on the r valve seat has occurred once before (reported August 25, 1970). Setpoint drift as found on valve 1105-A has never occurred before.

. I Sincerely,

/

V/. D_ fStf,4henson 3.Jc-Superintendent BBS:D3:smp ,

File /NRC D

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