ML19345B858

LER 80-084/01X-0:on 801113,leak Discovered in 2-inch Reactor Vessel Drain Line Connected to Reactor Water Cleanup Sys. Caused by Slag Inclusions in Pipe Coupling Weld Due to Fabrication Defect.Reactor Shut Down & Weld Repaired

ML19345B858
Person / Time
Site:	Pilgrim
Issue date:	11/28/1980
From:	BOSTON EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19345B853	List: ML19345B852 ML19345B858
References
LER-80-084-01X, LER-80-84-1X, NUDOCS 8012020622
Download: ML19345B858 (2)

Text

LICENSEE EVENT REPORT

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u LtJ@l 01 s 1 0l -i 01219 I 31@l1 68 69 11 EVENT i il.3le._LoJ@l1 DATE 14 ?S 11 REPORT 12 l DATE si 81 Ol@ 80 7 8 60 61 OOCK ET NUMB E R EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h

, M ion November 13. 1980 durine nn inanoceinn nf anoinmane viehin che nevuo11. nnevntine 1

[ TIT 1 I personnel observed water leaking from a 2 inch reactor vessel drain line which connects

[TTT1 Ivith the RWCV system. Closer insnection revealed that the leaks oricin was a 2 inch l Ic15I Inine coupline weld. The reactor which was critical at the time of the inspection i 1016 l lvas shutdown. The ninn une: renniraA nrine en rancene heino mndo crie4cn1 nn l-M lIovember 14. 1980. I I

101811 to 7 8 9 E CODE S SC E COMPONENT CODE SU8 00'E SU E IOTTl 7 8

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9 to 12 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION

,_ EVENT YEAR REPORT NO. CODE TYPE NO.

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,,. 21  ?? 23 24 26 27 28 29 30 31 32 N AC O ONP NT - MET HOURS S8 i POR 8. SUP L MANUF C RER l33Bl@l34 Zl@ l35Cl@ [,_A_j@ l 010 l2 l4 l l 41 l@ l42N l@ l43Nl@ lG l0 l8 l0 47l@

36 31 40 44 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i1IOIlThe faulty weld was isolated. cround out and the couoline revelded. A level three l 1 1 texaminer. assistine in the renair. detected slae inclusions in the veld. The I l i 121 IPresence of this slag predestined failure of the weld. This failure in the result I s lof a fabrication defect durine construction. I i

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% POWER OTH ER STATUS DIS O Y DISCOVERY DESCRIPTION STA '

1 5 W h IOl'110lh!" NA i d hl Operational Event l

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' JuViTY CO'# TENT RELFASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE Ni l 1 MA I 7

1 o 8 9 Lz.]@IzJ@l to 11 44 45 80 PERSONNEL EXPOSURES NVA*8 E R TYPE DESCF' 4 1 7 l 0 l 010 l@(,,,3,,jhl NA __

l PERSONNE L INJURIES N1JM8ER DESCRIPTION 7

1 a 8 9 l010lol@l 11 12 NA 80 l

LOSS OF CR DAMAGE TO FACluTY TYPE DESCRIPTION 7

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2 0 ISSUE10l @ DESCRIPTION NA l 68 69 1llllllllllll5 r,ii g

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M PREPARER PHONE:

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o BOSTON EDISON COMPANY PILGRIM NUCLEAR POWER STATION DOCKET Mo. 50 - 293 Attachment to LER 80-084/01X-0 Ou November 13, 1980, operating personnel observed leakage in the drywell.

A closer inspection revealed that a socket weld coupling had failed. The reactor was shutdown until repairs could be performed.

Weld number B-4-77 RI on a 2" socket weld coupling connection to a 2" Sched-ule 80 pipe on the Reactor Water Cleanup System located at approximately the 40 foot level in the drywell failed. The 2" stainless steel pipe was re-paired using a PNPS approved welding procedure. A liquid penetrant examina-tion was performed prior to excavating the area of the f ailure. The excava-tion extended to within approximately .025 inches of the interior wall. A filler weld was then performed consuming the remaining backup material to ensure a sound weld and enable sufff: lent penetration. Prior to acceptance of the weld, a final visual and liquid penetrant examination and a 950 psi hydrostatic test were performed.

In addition to inspections and repairs of the failed weld a liquid penetrant examination was performed on the opposite end weld of the socket coupling.

No degradation of this weld was detected.

A level three inspector observed slag inclusion in the weld material during excavation of weld B-4-77RI which is believed to be the primary cause of this event. I This failure was caused by a fabrication defect during construction and is not the result of thermal stress induced corrosion.

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