ML20090D653

AO-50-219/75-12:on 750426,low Reactor Pressure Core Spray Valve Permissive Pressure Switches Re 17B & C Found to Trip at Pressure Less than Tech Spec Value.Caused by Switch Repeatablilty.Switches Recalibr

ML20090D653
Person / Time
Site:	Oyster Creek
Issue date:	05/06/1975
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A Office of Nuclear Reactor Regulation
References
AO-50-219-75-12, NUDOCS 8303020230
Download: ML20090D653 (4)

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o o mO lersey Central Power & Light Company / 3 v_g' MAO:OON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J. 07000

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May 6, 1975

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Mr. A. Giambusso s ,4 ' , , , , - 'N U cd /

Director, Division of Reactor Licensing Office of Nuclear' Reactor Regulation /f[' I

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United States Nuclear Regulatory Commission 3 '

Washington, D. C. 20555 , ~_f, [/4)' ",,783 .

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Dear Mr. Giambusso:

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Subject:

Oyster Creek Station Docket No. 50-219 N/',]d:y-y,i -

y Abnormal Occurrence Report No. 50-219/75-12 The purpose of this letter is to forward to you the attached L; ca.ul caucu;.we repui 1.1.. sc 911ansc- with paragraph 0.0.2.a ef t!.:.

Technical Specifications.

Enclosed are forty copies of this submittal. ,

Very truly yours,

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Donald A. Ross, Manager Generating Stations-Nucicar pk Enclosures cc: Mr. J. P. O'Reilly, Director Office of Inspection and Enforcement, Region 1 8303020230 750506 #c'* o 5 PDR ADOCK 05000219 S Fpg

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O Jersey Central Power & Light Company o MADISON AVENUE AT PUNCH BOWL ROAD e MORRISTOWN.N.J.07960

• 201-539-6111

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OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/75-12 Report Date May 6, 19 75 i Occurrence Date

. April 26,1975 Identification of Occurrence Violation of the Technical Specifications, paragraph 3.1.1.D.3--Low Reactor Pressure Core Spray Valve Permissive Pressure Switches RE 17B and C were found to trip at pressures less than the minimum required value of 285 psig.

This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraphs 1.15B and D.

Conditions Prior to Occurrence The plant was shut down for the 1975 refueling. The reactor mode switch was in the REFUEL position with reactor coolant temperature less than 212*F.

Description of Occurrence ,

On saturday, April 26, 1975 at approximately 0300, while performing quarterly sur :cillance testing on the four Low Reactor Pressure Core Spray Valve Permssive Precsure Switches, it was discovered that switches RE 17B and C trieped at 278 psig and 280 psig, respectively. These values are less than thi Technical Specification limit of 285 psig. Pressure switches RE 17B and C were immediately recalibrated.

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A Abnormal Occurr(A,,e Report No. 50-219/75-12 Pags 2 The "as found" and "as left" switch settings were:

"As Found" Settings "As Left" Settings RE 17A 286 psig 286 psig RE 17B 278 psig 285 psig RE 17C , 280 psig 287 psig RE 17D 285 psig 285 psig-Apparent Cause of Occurrence The cause of this occurrence is switch repeatability.

Analysis of Occurrence The Core Spray System Parallel Isolation Valves open when a low-low reactor water 1cvel .and/or high drywell pressure condition exists in addition to a low reactor pressure condition (265 psig) . The four Low Reactor Pressure Core Spray Valve Permissive Pressure Switches sense the low reactor pressure condition and provide signals to the valve opening logic. Two of these switches (RE 17A and B) are associated with Core Spray System 1, and the other two switches (RE 17C and D) are associated with Core Spray System 2.

A trip of one switch in each core spray system is required to effect parallel isolation valve opening in that system. A review of the "as found" switch settings indicates that parallel isolation valves in both core spray systens would have opened at reactor pressures 3285 psig had a reactor low-low water level and/or high drywell pressure condition existed concurrently. The safety significance of this event is, therefore, considered to be the loss of switch redundancy. In addition, it is noted i

that the reactor has been maintained at atmospheric pressure during the current refueling outage and that the low reactor pressure permissive was, consequently, satisfied during this time period.

Corrective Action Immediate corrective action involved the recalibration of pressure switches RE 17B and C. A study will be conducted to determine the feasibility of raising the pressure switch settings in order to alleviate the problem of the pressure setpoint drifting to, a value less than 285 psig. Additional information concerning this type af problem is contained in the response to Question No.1 of Supplement No. 8 to Amendment No. 68 dated January 8, 1975.

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. n Abnorms1 Occurri.de Report No. S0-219/7S-12 Page 3 Failure Data 1

Manufacturer data pertinent to these switches are as follows:

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! Manufacture : Barksdale Type: Pressure Actuated Switch

! Range: 50-1200 psig Serial No.: B2T-A12SS (RE 17B)

B2T-M12SS (RE 17C) i 4

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