ML20084C848

Preliminary AO 50-219/74/44:on 740809,main Steam Line Low Pressure Switches RE23A,B,C & D Found to Trip at Pressure Less than Min of 860 Psig.Caused by Switch Repeatability. Setpoint Accuracy Being Investigated

ML20084C848
Person / Time
Site:	Oyster Creek
Issue date:	08/09/1974
From:	Carroll J, Edelhauser J JERSEY CENTRAL POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20084C806	List: ML20084C803 ML20084C848
References
AO-50-219-74-44, NUDOCS 8304080248
Download: ML20084C848 (5)

Text

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To: James P. C'Reilly h ,' I . ,.

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Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 4

Fro;a: Jersey Central Power 5 Light Company Oyster Creek Nuclear Generating ~ Station Docket #50-219 Forked River, New Jersey 08731

Subject:

Abnormal Occurrence Report No. 50-219/74/44

'The following is a prelininary report being subnitted in compliance 1 ith the Technical Specifications, paragraph 6.6.2, Preliminary Approval:

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I O o Initial Telephone Date of l Report Date: 8/9/74 Occurrence : 8/9/74 Initial Written Time of i Report Date: S/9/74 Occurrence : 1000 i

OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74/ 44 3 IDENTIFIC/JION Violation of the Technical Specifications, paragraph 2.3.7, OF OCCURRENCE:

Main Stean hine Ldu Pressure Switches, RE23A, RE23B, RE23C,

'. and RE23D, were found to trip at pressures less than the mininum required value of 860 psig.

'Ihis event is considered to be an abnormal occurrence as de-fined in the Technical Specifications, paragraph 1.15A.

insimim evina y stese st ete P~.rer " cutin: Chutdcun TO OCCURRENCE: Ilot Standby . Operation Col'd Shutdown Load Changes During Refueling Shutdown Routine Power Operation Routine Startup Other (Specify)

, Operation 4

Power: Reactor,1910 "Nt Electric, 650 We Flow: Recirc. , 59.3 X 106 lb/hr Feed., 7.133 X 106 lb/hr Reactor Pressure: 1020 psig Stack Gas: 27,500 pCi/sec DESCRIPTION OF On Friday, August 9,1974, at 1000, while performing a routine OCCURRENCE *:

surveillance test on the four Main Steam Line Low Pressure Switches, it was discovered that switches RE23A, RE23B, RS23C, and RE23D tripped, at 850 psig, 855 psig, 850 psig, and S47 psig, respectively. Thesd values are below the minimum required trip 4 e l

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Report No. 50-219/74/44 Page 2 )

Specification limit of 850 psig a 10 psig head correction factor. . >

The "as found" and "as Icft" switch settings we.re:

"As Found" Settin es "As .Left" Settines RE23A 850 psig 863 psig RE23B 855 psig 860 psig PI23C 850 psig 860 psig P223D S47 psig 863 psig APPARENT CAUSE Design Procedure OF OCCURRENCE: Manufacture Unusual Servico Condition Installation / Inc. Environnental Construction Component Failure Operator x Other (Specify)

The cause of this occurrence is switch repeatability, which is a recognized problea.

ALEYSIS OF As indicated in the bases' of the Technical Specifications, OCCURRENCE:

"The low pressure isolation of the Main Steam Lines at 850 psig was provided to give protection against fast reacto2-depressurization and the resultant rapid cooldown of the vessel. Advantage was taken of the scran feature which occurs when the Main Steam 1 solation Valves are closed to provide for reactor shutdown so that high power operation at icw reactor pressure does not occur, thus providing protec-tien for the fuel cladding integrity safety limit.

i The adverse consequences ofe r' actor isolation occurring at

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1 A5 normal occurrence I Report No. 50-219/74/44 Page 3 minimum value of S50 psig is limited to those effects atten- l i

dant to a greater than normal reactor cooldown rate. The fuel cladding integrity safety limit only comes into effect for power operation at reactor pressures 19ss than 600 psig or for power operation greater than 354 M3t with less than 10% recirculation flow. Therefore, the consequences of a 13 psig lower than normal reactor isolation and scram setpoint has no threatening effect whatsoever on the fuel cladding integrity.

The effects of a too rapid cooldown due to the lower isolation pressure are inconsequential since there is less than 20F dif-ference batmn the r ettr ti:n teger=nre fer SCO p;ig c.nd 837 psig.

CORRECTI\E Steam line pressure variation's during daily stop valve testing ACTION:

make it irpractical to include in the switch setpoint the nor-mal trip point variations to provide a sufficient margin above the Technical Specification limit.

Setpoint accuracy and tolerance in not only these instruments but in others as well is under investigation by Company and GPU personnel with General Electric Company.

FAILUPd3 DKTA: Manufacturer data, pertinent to those switdies are as folleus :

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Abnormal Occurrence '

Report No. 50-219/74/44 ~ Page 4 5 f Meletron Corp. (subsidiary of Barksdale) -

Los Angeles , California Pressure Actuated Switch '

Model 372 Catalog !!372-6SS49A-293 ': n Range 20-1400 psig -

f Proof Psi.1750 G Previous Abnomal Occurrence Reports involving those switches

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are: -

1. Lctter to Mr. A. Giarbusso from Mr. ' D. A.' Ross, dated De cenber 24, 1973. - /

2. Abnomal Occurrence Report No. 74-1 .

3. Abnornal Occurrence Report No. 74-9. -

4 Abnomal Occurrence Report No. 74-10. .

5 Abnormal Occurrence Report No. 74-12

6. Abnomal Occurrence Report No. 74-22

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7. Abnormal Occurrence Report No. 74-35'.

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8. Abnornal Occurrence Report No. 74-37.

9. Abnornal Occurrence Report No. 74-41. ,.

10. Abnormal Occurrence Report No. 74-42,

11. Abnomal Occurrence Report No. 7'4-43 av 4 i

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