ML20148T131

AO 50-219/74/34:on 740528-29,leakage Observed in Vicinity of Incore Flux Monitor Tube & Incore Flux Monitor Housing Penetration Located at Reactor Vessel Bottom.Cause Undetermined.Nsss & Mfg Contacted Re Corrective Action

ML20148T131
Person / Time
Site:	Oyster Creek
Issue date:	05/30/1974
From:	Sullivan J JERSEY CENTRAL POWER & LIGHT CO.
To:
References
AO-50-219-74-34, NUDOCS 8102190748
Download: ML20148T131 (3)

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'N DYS7hR CREEK NUCLEAR GENERATING STN110N~

PORK,BD RI\\'BR, NEtt JERSEY - 087311 s.

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. Abnoroal Occurrence v

4 50-219/74/ 34 Rep; ort.No.

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IDENTIFICATION-

' Violation of-ths Tcchnical Specifications, mar'agraph N/A,

0P' OCCURRENCE:

Indications.of coolcat 1cchage existing in the area or u

'incore flux ocnitor reactor vessel housing located at core coor-x c-

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,a Ris event is considered to be an abnormal-occurrence as de-o fined in' the Technical Specifications, paragraph 1.15E n

' 00NDITIONS PRIOR TO OCCURRENCE:

Steady State Power' Routino Shutdown Hot Standby Operation Cold Shutdown

_ Load Changes During x-Refueling, Shutdown Routine Power Operation Routino Startup Other (Specify)

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. Operation

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' h.e ivactor was in the REFUBL coda during'a hydrostatic test at'.850 p'sig pressure and with. coolant' t'e:gerature approxicctely U.:

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r D$5CitIPT10N On Tuesday, Hay 28, 1974, during a scheduled reactof v6ssef'"

0F OCCURRENCE:

hydrostatic test to inspect the' pressure boundary following 7,.

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refueling raintenance activities, Icakage was observed in the vicinity of an incore flux conitor tube located at the botte:s of the reitetor vessel. 'Further investigatico conducted on Wednesday [ Hay 29, 1974, showed evidence of possible Icakage in the area of an incere flux monitor housing penetration

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.Isca%d in the reactor vessel bottou r. cad. A second hydro-3-o

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i.%. static test was ccmducted'at a pressure of 850 psig at approx 1'-

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observed leaking between'the monitor housing and the reactor I

he leakage was measured under the conditionss of 850 vessel.

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, psig with. a terperature of 164"F, and calculated to be on. the

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order of approxicately 0.02 gallons per hour.

APPAPali CAUSE Design Procedure OF OCCURPECE:

Manufacture Unusual Service Condition Installation /.

Inca Envizcatental-Construction-Corponent Failure l

Other (Specify)

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.s 1he cause of this event has yet to be'dstermined; ANALYSIS OF.

As stated in FDSAR A"endt:ent #37, a postulated failure of the i

OCCUP2 5 CEi l.2 flux monitor tth would result in vessel leakage at a rate

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which would not cause excessive cladding <ter7eratures and for which core reflooding is p'ossible by engineered safety features.

U 1his situation is less severe than the design basis accident.

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To determine the consequences of a weld failure at a housing

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for an in-core conitor tube, it'is assumed that the weld between the housing and the reactor vessel bottc:a head fails, allowing the housing and the in-core monitor tube tobc ejected from the vessel. The hole provided in the botto:n head for the housing has a diameter of two inches; this is the assdmed break size.

1he hole has a break area of.0218 ft. Assuming worst condi-2

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tions, this results in peak clad tc::peratures less than 1000 F, as'ipdated in FDSAR Ar..ndment #67.

'Ihis yalue is well within

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zl acceptablo li=1ts of the applicable ECCS criteria.

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.m CORRECTIVE 1he n"' tar steam supply vendor and t9 reactor vessel manu-b k

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facturor have been ccatacted with rogar'd to this conditi'on.

Discussion will ensue as to the proper course of action to be taken to resolve this patter.

Reco::cendations will be forth-coming pending cc:plete review of this event by the Plant Opera-A tions Review Co:mittee.

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