ML20084C394

AO 50-219/74-52:on 741012,main Steam Line Low Pressure Switch RE23A Found to Trip at Pressure Less than Min of 860 Psig.Caused by Switch Repeatability.Ge Supplied Info to Reduce Setpoint

ML20084C394
Person / Time
Site:	Oyster Creek
Issue date:	10/21/1974
From:	Ross D JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084C398	List: ML20084C394 ML20084C419
References
AO-50-219-74-52, NUDOCS 8304080021
Download: ML20084C394 (4)

Text

l e (~

w f)^r L G)

Jersey Central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.07960

• 201-533-6111 nr.. . or r.,e General jj[,*[, Public Utahties Corporation SFSTE tr October 21, 1974

/g'$$h N -$

hy / ,N oy p.tCOy

~j

-a O C T ' yo C lg;\ g g .

'z?q, H f.3, g., W4l C. G: Ec ;7 ,C]

.- e ,

's _." !sj

'\ /p ' _

.C' Mr. A. Giambusso Deputy Director for Reactor Projects \//T'@iJ\Q>]

Directorate of Licensing United States Atomic Energy Commission Washington, D. C. 20545

Subject:

Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/74-52 The purpose of this letter is to forward to you the attached Abnormal Occurrence Report in compliance with paragraph 6.6.2.a of the Technical Specifi-cations.

Enclosed are forty copics of this submittal.

Very truly yours, sdL2 /

Donald A. Ross hhnager, Nuc1 car Generating Stations pk Enclosures cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region 1 0/7 8304080021 741021 /E Mc,P# ]()C}<jP PDR ADOCK 05000219 S PDR COPY SENT REGION _

0 O g.: N Jersey Central Power & Light Company MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.07960

• 201539-6111

.,..,r.,,

General .}. { Public Utilities Corporation SFST) .

0YSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74-S2 Report Date October 21, 1974 Occurrence Date October 12, 1974 Identification of Occurrence Violation of the Technical Specifications, paragraph 2.3.7, Main Steam Line Low Pressure Switch RE23A was found to trip at a pressure less than the mini-mum required value of 860 psig. This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15A.

Conditions Prior to Occurrence The plant was shut down with reactor coolant at a temperature less than 212*F.

Description of Occurrence On Saturday, October 12, 1974, at 0100, while performing a routine surveillance test on the four Main Steam Line Low Pressure Switches, it was discovered that switch RE23A tripped at 855 psig. This value is below the minimum required trip point of 860 psig, which is derived by adding to the Technical Specifica-tion limit of 850 psig a 10 psig head correction factor.

• Abnormal Occurrento Report No. 50-219/74-52 Page 2 The "as found" and "as left" switch settings were:

"As Found" Settings "As Left" Settings

- RE23A 855 psig 860 psig

, RE23B 870 psig 860 psig RE23C 860 psig 860 psig RE23D 860 psig 860 psig .

Apparent Cause of Occurrence The cause of this occurrence is the recognized problem of switch repeatability, i Analysis of Occurrence Four pressure switches in the reactor protection system (RPS) are provided to isolate the reactor in the event of low main steam line pressure. Two of these switches (RE23A and RE23C) are in RPS Channel 1, and the other two switches (RE23B and RE23D) are in RPS Channel 2. Low pressure signals from two pressure switches, one in each RPS channel, are required to effect main steam isolation valve closure. A review of the "as found" switch settings indicates that reactor isolation would have occurred at the minimum required pressure had a main steam line low pressure condition existed. Consequently, this event is considered to have no safety significance.

Corrective Action Steam line pressure variations during daily stop valve testing make it impractical

, to include in the switch setpoint the normal trip point variations to provide a sufficient margin above the Technical Specification limit.

The General Electric Company has furnished information on the feasibility _ of' reducing the 850 psig setpoint to a lower value. This information is being evaluated by the Oyster Creek Nuclear Station staff, and a Technical Specifi-cation Change Request may be submitted as a result of this evaluation.

i Failure Data I

! bbnufacturer data pertinent to these switches are as follows:

t

. Meletron Corporation (subsidiary of Barksdale) ,

Los Angeles, California l Pressure Actuated Switch 1 Model 372 'l Catalog No. 372-6SS49A-293 l Range 20-1400 psig

• Proof Psi 1750 G l

-1 1

. )

O r Abnormal Occurren / Report No. 74-219/74-52 ( Page 3 I

Previous abnormal occurrence reports involving these switches are:

1. Letter to Mr. A. Giambusso from D. A. Ross, dated December 24, 1973.

2. Abnormal Occurrence Report No. 50-219/74-1.

i 3. Abnormal Occurrence Report No. 50-219/74-9.

I

4. Abnormal Occurrence Report No. 50-219/74-10.

5. Abnormal Occurrence Report No. 50-219/74-12.

6. Abnormal Occurrence Report No. 50-219/74-22.

7. Abnormal Occurrence Report No. 50-219/74-35.

8. Abnormal Occurrence Report No. 50-219/74-37.

• i

9. Abnormal Occurrence Report No. 50-219/74-41.

10. Abnormal Occurrence Report No. 50-219/74-42.

11. Abnormal Occurrence Report No. 50-219/74-43.

12. Abnormal Occurrence Report No. 50-219/74-49.

13. Abnormal Occurrence Report No. 50-219/74-51.

f w

Omosw