ML20084C916

AO 50-219/74/42:on 740725,main Steam Line Low Pressure Switches RE23A,B,C & D Found to Trip at Pressures Less than Min of 860 Psig.Caused by Switch Repeatability.Setpoint Accuracy & Tolerence Under Investigation

ML20084C916
Person / Time
Site:	Oyster Creek
Issue date:	08/02/1974
From:	Finfrock I JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-50-219-74-42, NUDOCS 8304080340
Download: ML20084C916 (4)

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fersNy Central Power & Light Company J N'j MADISON AVENUE AT PUNCH BOWL ROAD e MORRISTOWN, N.J.07960 = 201-539-6111

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, jjf,,*, Pubhc Utihties Corporation August 2, 1974 Mr. A. Giambusso l Deputy Director for Reactor Projects Directorate of Licensing United States Atomic Energy Commission Washington, D. C. 20545

Subject:

Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/74/42 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 Specifications.

Enclosed are forty copics of this submittal.

Veiy truly yours, 3

I o Ivan R. Finf,r'ock ,./Jr.

Vice President cs Enclosures cc: Mr. J. P. O'Reilly , Director '

i Directorate of Regulatory Operations, Region I j

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Jersey Central Power & Light Company &

MADISON AVENUE AT PUNCH BOWL ROAD

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General gyj{ Public Utihties Corporation

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OYSTER CREEK NUCLEAR GENERATING STATION l

FORKED RIVER, NEW JERSEY 08731 l Abnormal Occurrence i Report No. 50-219/74/42 -

Report Date August 2,1974 j Occurrence Date

! July 25, 1974 Identification of Occurrence i

Violation of the Technical S7ecifications, paragraph 2.3.7, main steam line low pressure switches RE23A, B, C, and D were found to trip at pressures Icss than the minimum 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 at steady state power with major parameters as follows:

Power: Reactor,1898 FMt Electric, 653 FMe Flow: Recirculation, 15.8 x 10'+ gpm Feedwater, 7.05 x 106 lb/hr Reactor Pressure: 1020 psig Stack Gas: 13,065 pCi/sec Description of Occurrence On Thursday, July 25,1974, at 1015, while performing a routinc surveillance test on the four main stean line low pressure switches, it was discovered that switches RE23A, B, C, and D t ri[' ped at 849, 854, S59, and 855 psig, respectively. These values are below the minimum required trip point of 860 psig which is derived by adding to the Technical Specification limit of 850 psig, a 10 psig head correction factor.

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. U. U Abnormal Occurrence Report No. 50-219/74/42 Page 2 The "as found" and "as Icft" switch settings were:

"As Found" Settings "As Left" Settings RE23A 849 psig 861 psig RE23B 854 psig 860 psig RE23C 859 psig 862 psig RE23D 855 psig 862 psig Apparent Cause of Occurrence The cause of this occurrence is the recognized probicm of switch repeatability.

Analysis of ' Occurrence As indicated in the bases of the Technical Specifications, "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 cooldown 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 protection for the fuel cladding integrity safety limit."

The adverse consequences of reactor isolation occurring at reactor pressure approximately 11 psig below the specified minimum value of 860 psig is limited to those effects attendant 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 than 600 spig or for power operation greater than 354 FMt with less than 10'4 recirculation flow. Therefore, the consequences of a 11 psig lower than normal reactor isolation and scram set point has no threatening effect whatsoever on the fuel cladding integrity.

1he effects of a too rapid cooldown due to the lower isolation pressure are inconsequential since there is less than 2'F difference between the saturation tenperature for 850 psig and 839 psig.

Corrective Action Set point accuracy and tolerance in not only these instruments but in others as well are under investigation by Jersey Central Power 6 Light Company, GPU Service Corporation, and General Electric Company personnel. This investigation was described in detail in Abnormal Occurrence No. 50-219/74/35.

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! ~ ' Abnardal Occurrence Report No. 50-219/74/42 Page 3 [

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Failure Data

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Manufacturer data pertinent to these switches are as follows:

Meletron Corporation (subsidiary of Barksdale)

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

} Proof Psi 1750 G Previous abnormal occurrence reports involving these switches are:

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

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

] 3. Abnormal Occurrence Report No. 50-219/74/9 1

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

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

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

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

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

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

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Abnozcal occurrence

,- . Report No. 50-210/74/'42 IDDITIFICATION Violation of the Technical Specifications, paragrcph 2.3.7, OP OCCURPRICB: .

. Hain Steam Line Low Pressure Switches RE23A, B, C, and D, found

. to trip at pressures less then the minicus requi'red'value of

, 860 psig. '

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7his event is censidered to be(en abnormal occurrenco 'as de-fined 16 the Technical Specifications, paragraph I'.15A.

. ,, . ',e - 4, ; , (, 2 Steady Sthte Powor.. "

ElDITIC'iS PRIOR -

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Routino. Shutdown-10 OCCUarmiCE: llot Stendby >

Operation y Cold shutdcun Load 01 angas During

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Refualing 5:iutdein '

P,outine Poner Operation Routino Startup-

Other (Specify)

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Power: Reactor, 1898 l.Ht Bloc. , 653 1.'.le Flow:* Rocirc.,15.8 X 104 gpa.

Food., 7.05 X IOC lb/hr.

Ronctor Prossuro: 1020 psig Stack Gas: ~ 13,065 pCi/ soc . '

DESCRIPTicN OF On Thursday, July 25,1974, at 1015, while performing a routino OCCURRCICE:

survellicnco test on tho four Hain Steam Lino Low Pressuro Switches, it was discovered that switches RB23A, B, C,. and D tripped at 849, 854, 859, and 855 psigf 'roshoctiv[> y. Thos'e values aro below the ninitum required trip point of 860 psig _._

which is' derived by adding to the Technical Specification limit of 850 psig a 10 psig head correction factor.

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beh found" and "as Icft" switdih. tings' wore: '

.- I "As Found" Settings '

"As.left"' Settings

' i l RB23A 849 psig 861 psig

) RE23B 854 psig , 860 psig RB23C 859 psig ./ 862 psig.

RB23D 855'psig 862 psig APPt. RENT cat 1SH X Design _ Procedure OF 0CCURRENCE: 14anufacture _ Unusual Servico Condition Installation / ~~'

. Ince Envirennental Construction . Co penent Failuro Operator-

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Other (Spacify)

>=,,." The cause .of this occurrence is switch repeatebility, which is a recognized problon. M ANA1.YSIS OF As indicated in the bases of the Technical Spacifications, ,

OCCURFECE: .

,; , . "The low pressure isolation of the }!ain Stena Lines at 850

.w psig was provided to give protection against. fast reactor' depressurizatib and the resultant rcpid cooldown.of the vessel. Advantcge was taken of the scran fodure which occurs when tho }!ain Stoan Isolation valves aro closed to-provide for reactor shutdown so that high pc ter oporation at low reactor pressure does not occur, thus providing protoc-tion for the fuel cladding integrity safety limit."

Tho adverso conscquences of roactor isolation occurring at reactor pressuro approxicatoly 11 psig below the specified minit:um value of 860. psig is limited'to those offects atten-dont to a greator than nomal reactor cooldown rate. The fuel cladding integrity safety limit only comes into offect

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ir for- or operation, at.roactor press os .lo:is then. 600/ psig. .

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p 10brecirculation flom"Ihcrofore, the: consequences,of.a... -

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e cladding, integrityi

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Tho .cffects of a too rapid.ccoldown duo.to tho lower isola-

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tion pressure are incensequential since thoro is'1 css than-W 26p difference between the saturation temperaturo.for 850' psig and 839 psig.

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CORPICTIVE f' Sctpoint' accuracy nnd tolor::nco..in.notienly:theso inctrucents ACTION: ' - '

but in others as well is under. investigation by cc pany. and GPU:personnot with General'Elcetric Co:panye ,

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FAII173 DATA: Manufacturer data pertinent to,these switches are as; follows:

, Heletron Corp. (srbsidiary of Darksdale) .,.

' Ins Angeles, Califomia e ,. ;

,. Pressuro Actuated Switch. y ii.' :

Hodel 372

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Cataloa 0372-6SSOA-293 -

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Range 20-1400-13sig -

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Proof. Psi.1750 C. -

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Previous Abnorral Occurrence: Twports invol'ving. i.imse swit'ches

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are:

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1. Lotter to Hr. A. Ginrbusso from Mr. D. A. Rens dated Decc:bar 24, 1973. .

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2i Abnorr.210:curronco Report.No. 74-1. , '

3. Abnorual Occurrence Reitort No. 74-9..

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Directorate of Regulatory Operations Region 1 ,

631 Park Avenuo King of Pntssia, Pennsylvania 19406 Pan: Jersey Central Powcr G Light.Co:pany-Oyster Cicek Huclear Generating Station.

Docket 850 219 07651 Forked River, New Jorsey ..

Subject:

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

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'Iho following i~s a prolicinary report being st6nitted-i in. corpli=1ce with the Technical:Specificaticas, paragraph-6.6.2.- 7 ;4

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