ML19209C893

LER 79-033/03L-0:on 790917,electromatic Relief Valve Pressure Switch 1A83A Tripped at Pressure in Excess of Limit.Caused by Defective High Pressure Microswitch. Replacement Switch Installed

ML19209C893
Person / Time
Site:	Oyster Creek
Issue date:	10/10/1979
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19209C887	List: ML19209C886 ML19209C893
References
LER-79-033-03L, LER-79-33-3L, NUDOCS 7910180446
Download: ML19209C893 (3)

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7 8 60 61 DOCKET NUMB ER EVENT OEsCRIPTION AND PROBABLE CONSEQUENCES h 10171 While performino surveillance on five electromatic reifef valva nracenra I F6 TT1 I switches, it was found that IA83A tripped at a value in excess of the i O 4 I maximum allowable point of 1059 psig. The initial "As Found" trio point 1 0 s_ I was 1175 psig. Successive tests found various readings between 1050 l O 6 I and 1175 psig. It was then determined that the high pressure micro- l o 7 I switch was defective and the occurrence could not be attributed to l 0 a 1 instrument drift. 80 I

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• l 1 l 7 8 9 80 SA  % POWER OTHER STATUS Dis O RY DISCOVERY DESCRIPTION Hot Standby i s lGl@ l0l0l0l@l l lBl@l Surveillance Testino l A TIVITY CO TENT RELE ASED OF RELEASE AMMUNT OF ACTIVITY LOC ATION OF RELE ASE 1 6 Z l @ 'l Z lgl NA l l NA l PERSONNEL EXPOS ES NUMBER TYPE DESCRIPTION NA 1 7 l 0 l 0 l 0 l@l Zl@l 7 * * " t 8"

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l 7 8 9 10 30 ISS g l YEf@DE CRIPTION l Weekly news release - October 16, 1979 l lllll;;;;;;;l 7 8 9 to 68 69 so NAME OF PREPARER onald A. Ross PHONE: 201-455-8785

Jersey Central Power & Light Company

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LM7 b '(f g )j Madison Avenue at Punch Bowl Road Morristown, New Jersey 07360 (201)455-8200 OYSTER CREEK NUCLEAR GENEP.ATING STATION Forked River, New Jersey 08731 Licensee Event Report Reportable Occurrence No. 50-219/79-33/3L-0 Report Date October 10, 1979 Occurrence Date September 17, 1979 Identification of Occurrence Violation of the Technical Specifications, paragraph 2.3.4 when electromatic relief valve pressure switch 1A83A was found to trip at a pressure in excess of the maximum allowable value. This event is considered to be a reportable occurrence as defined in the Technical Specifications, paragraph 6.9.2.b.1.

Conditions Prior to Occurrence The plant was in hot standby condition.

Temperature - 460*F.

Pressure - 460 psig Water level - 70" yarway SRM counts were between 45 and 70 Description of Occurrence On Honday, Septen.ber 17, 1979, while performing surveillance on five electro-matic relief valve pressure switches, it was found that IA83A tripped at a value in excess of the maximum allowable trip point of 1059 psig. The trip point is derived by adding an appropriate head correction factor to the Technical Specification limit. The initial "As Found" trip point was 1175 psig.

Successive testing found various readings between 1050 and 1175 psig. It was then determined that the :;tgh pressure micro-switch was defective and the discrepancies could not te attributed to instrument drift.

Apparent Cause of Occurrence The cause of this occurrence is attributed to component failure.

1176 151 Jersey Central Power & Light Company is a Member of the General Pubhc Utilities System

Reportable Occurrence.No. 50-219/79-33/3L-0 Page 2 October 10, 1979 Analysis of Occurrence The reIIef valves are provided to remove sufficient energy from the primary system to prevent the safety valves from lifting during a transient. The limiting pressure transient is a turbine trip from rated design power with a failure of the bypass to function. Under these conditions, the five relief valves are required to operate in order to prevent reaching the lowest set point of the primary system safety valves. It should be noted that a 25 psig margin exists between the resulting peak pressure and the lowest safety valve set point as added assurance that the safety valves will not Ilft during this transient. Now with valve NR108A actuating at over 100 psig above the maximum allowable trip point and assuming the most Ilmiting pressure transient has occurred, the lowest set point safety valve may have been required to actuate in order to Ilmit the pressure transient.

Corrective Action Pressure switch IA83A has been replaced with a new Bourdon Tube Pressure Switch Assembly, Model No. B25-H-1255, manufactured by Barksdale.

Failure Data Manufacturer: Barksdale Model: B25-H-1255 1176 152