ML19259C151

LER 79-015/03L-0 on 790507:during Routine Surveillance Testing,Setpoint of Pcrv Rupture Disc M-11702 Found to Be 826 Psig.Caused by Calibr Drift.Disc Recalbr

ML19259C151
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/06/1979
From:	Gahm J PUBLIC SERVICE CO. OF COLORADO
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19259C146	List: ML19259C145 ML19259C151
References
LER-79-015-03L, LER-79-15-3L, NUDOCS 7906120414
Download: ML19259C151 (4)

Text

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REPORT DATE: June 6, 1979 REPORTABLE OCCURRENCE 79-15 ISSUE O OCCURRENCE DATE: May 7, 1979 Page 1 of 3 FORT ST. VRAIN NU"I, EAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT No. 50-267/ 79-15 /03-L-0

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- 2 Final IDENTIFICATION OF OCCURRENCE:

During a routine surveillance calibratian check performed on May 5,1979, the

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setpoint of the PCRV rupture disc assembly M-11702 was found to be 826 psig.

Since this setpoint is higher than the 812 psig + 1% allowable by Fort St.

Vrain Technical Specification LSSS 3.3.2(c), it is being reported per Fort S t. Vrain Technical Specification AC 7.5.2(b)l.

EVENT DESCRIPTION:

With the reactor shutdown and depressurized for refueling, low set rupture disc, M-11702, was removed from service for a scheduled surveillance calibra-tion bench test. The "as found" pressure setpoint was 826 psig. The accep-tance criterion of LSSS 3.3.2(c) requires the set pressure to be 812 psig +

1% (804 psig to 820 psig).

Refer to Figure 1. Before the test gas pressure is applied the cutter, 1 ,

is removed and a s ville washers, ($)pecial . ring These washers is installed to limit snap over whenthe the travel of theisBel set pressure e-reached.

Ad ustment of the set pressure is made by positioning of the threaded ring, 3 . When the set pressure is reached, the diaphragm and washers travel a ew thousandths of an inch, which produces an audible " thump".

CAUSE DESCRIPTION:

The rupture disc being out of tolerance was caused by calibration drif t over the two years it had been in service since its last calibration surveillance.

CORRECTIVE ACTION: -

The rupture disc was calibrated to 812 psig and returned to service.

No further corrective action is anticipated or required.

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REPORTABLE OCCURRENCE 79-15 ISSUE O Page 2 of 3 E

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Prepared by: h_ > .

Asa B. Reed ' ~

Technical Services Technician Reviewed by: . .

, . p Gahm Technical Services Supervisor Reviewed by:

Frank M. Mathie Operations Manager Approved by:

• b M, Don Warembourg (/

Manager, Nuclear Production 2285 095

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NRC FORM 366 U. S. NUCLEAR REGULATORY COMMISSION (7 77)' *

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LICENSEE EVENT REPORT CONTROL BLOCK:

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(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 7 0 i 8 9 lCl0lFlSlVl1l@l0l0 - l 0 l0 l0 LICENSEE CODE 14 15 0 l 0 l- l 0 l 0 25l@l264 l1LICENSE LICENSE NUMsEM l1 2TYPE l 0JOl@l$7 CAT l

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EVENT DATE REPORT DATd ,

l EVENT DESCRIPTION AND PROBABLE CONSEQUENCES O'o o 2 l During refueling shutdown, while performing routine surveillance testing of PCRV rup- l g 3  ; ture disc M-ll702 its setpoint was found to be 826 psig. This is outside the 812 l ,

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g , gp sig + 1% allowed by Fort St. Vrain Technical Specification LSSS 3.3.2(c) and is o s I being reported per Fort St. Vrain Technical Specification AC 7.5.2(b)l. The reactor ;

o 6 l had not been overpresSurized during this surveillance interval and there was no l o 7 i effect on plant operation. l o 8  !

l 80 7 8 9 E CODE SUSC E COMPCNENT CODE SL8 CODE SU E 7

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lClA @ Wh lZ h l Xl Xl Xl Xl Xl Xlh l Z lh l Z h 9 to 11 12 13 18 19 20 SEOUENTI AL OCCURRENCE REPORT REVISION EVENT YEAR REPORT NO. CODE TYPE NO.

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33 34 JS 40 42 43 4 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i io Cause of the problem was calibration drif t. The ructure disc was calibrated to the y proper setpoint and returned to service. No further corrective action anticipated or 1 i

, l required. l 1 3 l 1 4 ]  !

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$A  % POWER OTHER STATUS DIS O RY DISCOVERY DESCRIPTION 1 5 Wh l0 l0 l0 lhl N/A l B lhlScheduledSurveillanceTest  !

ACTtvlTY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 1 6 h dj@l N/A l l N/A l 7 8 9 10 11 44 45 80 ~

PERSONNEL EXPOSURES NUMBER DESCR,PTION Ii 7 l0 0 l 0 lhlTYPEZlhlN/A " "

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,ERSON~EL iN;UR,Es i a NuM8ER l 0 l 0 l 0 l@l12 N/A oESCRiPTiONh@} Q96 l 7 8 9 11 80 LOSS OF OR DAMAGE TO FACILITY TYPE Of SCRIPTION 1 9 lZl@l N/A l 7 8 9 10 80 DE CRIPTION

• 2 o lN ISSUEfhl N/A f 4 l llllll llIl1lI 7 8 9 to /p 68 69 80 ;

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