ML20107H915

Informs That Rept Being Submitted for Info Per Telcon of 740425

ML20107H915
Person / Time
Site:	Oyster Creek
Issue date:	04/25/1974
From:	Carroll J JERSEY CENTRAL POWER & LIGHT CO.
To:	O Reilly J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML18039A986	List: IR 05000219/1970007 IR 05000219/1971001 IR 05000219/1971002 IR 05000219/1971003 IR 05000219/1971004 IR 05000219/1971005 IR 05000219/1972001 IR 05000219/1972002 IR 05000219/1972003 IR 05000219/1972004 IR 05000219/1972005 IR 05000219/1972013 IR 05000219/1972025 IR 05000219/1973003 IR 05000219/1973004 IR 05000219/1973006 IR 05000219/1973007 IR 05000219/1973008 IR 05000219/1973009 IR 05000219/1973010 IR 05000219/1973011 IR 05000219/1973012 IR 05000219/1973013 IR 05000219/1973014 IR 05000219/1973015 IR 05000219/1973016 IR 05000219/1973017 IR 05000219/1973019 IR 05000219/1973020 IR 05000219/1973021 IR 05000219/1973022 IR 05000219/1973023 IR 05000219/1974001 IR 05000219/1974002 IR 05000219/1974003 IR 05000219/1974004 IR 05000219/1974005 IR 05000219/1974006 IR 05000219/1974007 IR 05000219/1974008 IR 05000219/1974009 IR 05000219/1974010 IR 05000219/1974011 IR 05000219/1974012 IR 05000219/1974013 IR 05000219/1974014 IR 05000219/1974015 IR 05000219/1974016 IR 05000219/1974017 IR 05000219/1974018 ... further results
References
FOIA-95-258 NUDOCS 9604240265
Download: ML20107H915 (1)

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To

' James P. O'Reilly Directorate of Regulatory Operations Region I.,

631 Park Avenue 1

King of Prussia, Pennsylvania 19406' Pion:

Jersey. Central Power 4 Light Company Oyster Creck Nuclear Generating Station, Docket #50-219 j

Perked River, New Jersey 08731

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Subject:

1he following report is being semitted for i'

your information as per phone conversation 1

of April 25, 1974.

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4/25174 i

h/T. Carroll, Jr. f Date i

i cc: Mr. A. Giambusso 3

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960'42402'65 960213 PDR FOIA DEKOK95-258 PDR

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Initici Written Time cf 4

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Repost.Datos d/2' T4.

Occurrence 3

1100 w

M8111R CRBEK NUCLEAR' GEN 5 RATING STATI(W

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PORKBD.. RIVER, NBW'JBR$2Y 08731

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IDENTIFICATION -

Cracking of torus to drywell vacuum. breaker valve V-26-2 disc j

OF OCWARBNG:

j at junction of disc bo# and stem. 1his failure coupletely separated the stem from the disc body and would have rendered j

j' the vacuum breaker valve inoperative had it occurred teder nonsal operating conditions.

i 1 l

Dis event is considered to be an abnormal occurrence as de-l l

' fined in the Technical Specifications, paragraph 1.15D.

CONDITI(MS PRIOR Stes # State Power Routine Shutdown j,

10 OCCURRENCB:

Hot Standby Operation

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Refueling Shutdown Routine Power Operation Cold shutdown Imad Changes During l

X Routine Startup Other (Specify)

Operation 4

he reactor mode switch was in the REPUBL position and i

j reactor coolant temperaturw was approximately 103'F.

l DBSCRIPTION At approximately 1100'on April 24, 1974, while contractor OP OCCURRENCE:

l' personnel were. disassembling torus to drywell vacuum breaker i

valve V-26 2 for inspection and maintenance work, the valve disc cracked at the junction of the disc body and' stem.

no-disc body and stem are made of cast aluminus and cast as one-9 piece.

This failure completely separated the ste' n from the-disc body. At the time of the failure, the cont setor hi 1

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persaisial w:n tapping the associated disc nut in an effart r

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to free and ultimately remove the nut from the disc stem.

his tapping was also used to free disc nuts on ninefpre-viously disassepled torus to drywell vacuum breaker valves.

! }l APPARluff CAUSE-Design Procedure OP OCCURRENCE:-

Manufacture thiusual Service Condition j

, Installation /

Inc. Environmental-Const metion Component pailure j

Operator Other (Specify) s y

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' Initial visual examination of the crack surfaces revealed that 1

i most of this area was clean. Mcwever, some darkened (dirty)

!l areas were observed around the edges of the crack surfaces.

ji his would indicate that the cracking started sometime before j*

I, the complete disc failure on April 24, 1974. 1he apparent

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cause of this occurrence is mder investigation at this time.

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!1 ANALYSIS OP.

1his valve disc failure is considered to have minimal safety j :

OCCURRENCE:

significance. Although the valve (V-26-2) would have been s

rendered inoperative had the failure occurred under normal operating conditions, the applicable requimments for torus to drywell vacuum bmaker valve operability specified in paragraph 3.5.A.3 of the Technical Specifications would have j,-

been-satisfied. However, the drywell-torus vacuum breaker 1 ;

1 valves are also rhuivis"to'be ' closed;during pipe break acci-

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dents (particularly small breaks) to assure proper steam

[i condensation and prevent torus overpressure. 1he safety

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,J r significance of this event is that valve,V-26-2 might not have performed this function had the disc failum occurred s

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during normal operating conditions and the disc been.subse--

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quently removed fna its seat (by torus overpussure, weekly i

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operability testing, etc.).

ODMCriVB'l '

The discs of the other thirteen torus to drywell vaasum i

ACTION:

l betaker valves will be laspected for cracking in the sua li

. l of the disc body-stes junction. Additional items of cor-i rective action will be determined following nylew of this i

i incident by the Plant Operations Review Committee.

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FAILURE DATA:

Basic valve data are as follows:

Manufacturer: Atwood. 4 Norrill t

Type: Oseck Valve j

Disc Material: Cast Aluminum i.

Vent Area:.1.75 square feet per valve l

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' Pawpared by.'

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