ML20084C913

Preliminary AO 50-219/74/43:on 740802,main Steam Line Low Pressure Switch RE23B Found to Trip at Pressure Less than Min of 860 Psig.Caused by Switch Repeatability.Set Point Accuracy & Tolerance Being Investigated by GE

ML20084C913
Person / Time
Site:	Oyster Creek
Issue date:	08/02/1974
From:	Carroll J, Rone A JERSEY CENTRAL POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
AO-50-219-74-43, NUDOCS 8304080337
Download: ML20084C913 (5)

Text

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To: James P. O'Reilly ,

Directorate of Regulatory Operatio'ns  :-'

Region I

, 631 -Park Avenue ,

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Oyster Croek Nuc1 car Generating Station T ' .. . - '-

Docket #50-319/74/43 \ \ ' #.c' ,j7'%

Forkcd River, New Jersey 08731 y'N ' ),' '

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Subject:

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

• Tuu fv11vwine is a pacilwiuary report being sunmirren in compliance with the Technical Specifications paragraph 6.6.2.

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Preliminary Approval: i d t

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J. T. Carrell, Jr[ Date  !

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. Initial.Te,leghene Report Dat,c:

O8/2/74 Date of Occurrence:

O 8/2/74 Initial Written Time of Report Date: 8/2/ 74 Occurrence :- '1000 0YSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74/ 43 IDENTIFICATION Violation of the Technical Specifications, paragraph 2.3.7, OF OCCURRENCE:

14ain Steam Line Low Pressure Switch, RE23B, was found to trip at a pressuro less than the minircum required value of 860 psig.

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

CGNDITIONS PRIOR x St ' idy State Power Routine Shutdown TO OCCURTINCE: llot S tandby nperation Cold Ch n du.... ~

Load Chuu m Dadau Refueling Shutdown Routine Power Operation Routine Startup Other (Specify)

Operation Power: Ra.ctor,1906 EVt Electrf 2, 638 Mie Flow: Recirc., 60.0 X 106 lb/hr Feed., 7.13 X 106 lb/hr Reactor Pressure: 1020 psig Stack Gas : 11,200 pCi/sec DESCRIPTION OF On Friday, August 2,1974, at 1000, while performing a routine OCCURP4NCE:

surycillance test on the four Main Steam Line Low Pressure Switches, it was discovered that switch RE23B tripped at 655 psig. His value is below the minimum required trip point of i 860 psig which is derived by adding to the Technical Speci fi-cation limit of 650 psig a 10 psig head correction factor.

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i Abnormal *Occarrence Report No.- 50-219/74/43 o 0-Page 2 i

. The "as found" and "as Icft" switch settings were:

1 j "As Found" Settings "As Left" Se ttints i

! RE23A 863 psig 863 psig  ;

. RE23B 855 psig #

863 psig '

j RE23C 860 psig 860 psig RE23D 863 psig ,

863 psig ,

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l APPARENT CAUSE Design Procedure j OF OCCURRESCE: Manufacture Unusual Service Condition 4

Installation / Inc. Environmental

, Construction' Component Failure

Operator x Other (Specify) l Steam line pressure variations during daily stop valve testing l make it impractical to include in the switch setpoint the nor-mal trip point variations to provide a sufficient margin above the Tedinical Specification limit.

ANALYSIS 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 reactor depressurization and the resultant rapid cooldcun of the vessel. Advantage was taken of the scram feature which occurs when the Main Steam Isolation Valves are closed to provide for reactor shutdown so that high power operation at low reactor pressure does not occur, thus providing protec-tion for the fuel cladding integrity safety limit.

1he adverse consequsaces of reactor isolation occurring at r

reactor pressure approximately S psig below the specified minir.um value of S60 psig is linited to those effects atten-4

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l Abnormal Occurrence Report No. 50-219/74/43 Page 3 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 less t'han 600 psig or for power operation greater than 354 MNt with less than l 10% recirculation flow. Therefore, the consequences of a 5 psig lower than normal reactor isolation and scram setpoint has no threatening effect whatsoever on the feel cladding l

l Integrity.

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The effects of a too rapid cooldown due to the lower isola- -

tion pressure are inconsequential since there is less than 10 F difference between the saturation temperature for 850 i

psig and 845 psig. ,

CORRECTIVE Setpoing accuracy and tolerance in not only these instruments ACTION:

but in others as well is under investigation by Company and GPU personnel with General Elcetric Company.

FAILURE DATA: Manufacture data pertinent to these switches are as follows:

Meletron Corp. (subsidiary of Barksdale)

Los Angeles, California Pressure Actuated Switch l Model 372 l Catalog #372-6SS49A-293 l

Range 20-1400 psig Proof Psi.1750 G 1

Previous Abnormal Occurrence Reports involving these switches i

are:

1. Letter to Mr. A. Giachusso fron Mr. D. A. Poss, dated Deccaber 24, 1973 L. $w

, Abnormal Oc,currence Report No. 50-219/74/43 Page 4

2. Abnormal Occurrence Report No. 74-1.

3. Abnormal Occurrence Report No., 74-9.

4. Abnormal Occurrence Report No. 74-10

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5. Abnormal Occurrence Report No. 74-12,

6. Abnomal Occurrence Report No. 74-22.

7. Abnomal Occurrence Report No. 74-35. .

8. Abnomal Occurrence Report No. 74-37.

9. Abnomal Occurrence Report No. 74-41.

10. Abnomal Occurrence Report No. 74-42.

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Prepared by: /jl ' // /D

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