ML20039C112

Updated LER 81-011/03X-1:on 810507,leak Discovered in Socket Weld Reducing Fitting.Caused by Intergranular Stress Corrosion Cracking.All Similar Fittings Replaced W/Differently Designed Fitting Less Susceptible to Failure

ML20039C112
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	12/17/1981
From:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20039C098	List: ML20039C097 ML20039C112
References
LER-81-011-03X, LER-81-11-3X, NUDOCS 8112280418
Download: ML20039C112 (2)

Text

NRC FORM *i64 UPDATE REPORT U.S. NUCLEAR REGULATORY COMMISSION (7 77)

LICENSEE EVENT REPORT LER 81-11/3X C NTROL stock: l I

l l l l l l@

6 (PLEASE PRINT OR TYPE ALL REOUIRED INFORMATIOrdi j o l t l l V I T lV lY l Sl 1l 0 l0 l- l 01010 l 010 l- l 0 ! 0 25l@l264 l1LICENSE l1 l1TYPE l1 JJl@lSi CAT $8l@

l 8 9 uCENSEE CODE 14 5 uCENSE NuM8ER CCN'T IoIil

' d cuRC lh 60 hl0 l5 l0 l0 63 l0 l217 l1 @l 069 l 5EVl ENT OOCKET NLMS ER 68 0 DATE l 7 l8 il @l 1l 2l 1] 7l 8l 1l@

14 75 REPORT C A. E $3 EVENT DESCRIPTION AND PROBABLE CONSECUENCES h t o 121 l Durine normal operation of the Reactor Water Cleanun System rmrfnn onernent  !

Io ja t t surveillance discovered a small leak in a 1" X 3/4" socket veld reducine fittine I lo 64I I in the tube-side drain line of Recenerative Heat Exchanger F-15-1A upstream of l 1o isi I valve V12-41A. There were no consequences adverse to the pualic health and l lo is l I safety as a result of this event. Similar previous occurrences were reported I lo t;} l to the Commission as LER 79-01. 80-37 and 80-41. I lots!I I SYSTEM CAUSE CAUSE COVP VA LV E COCE CCCE SL8COCE COMPONENT CCOE SU8CO DE SUSCOCE loi91 l Cl Gl h y h lD lh l PI I!P lE IX lX lh Wh dh 7 8 9 to 11 12 13 18 19 20

_ SE OUENTI AL CCCURRENCE REPORT REVISION lea ao EVENT YEAR REPORT NO. C00E TYPi N O.

Ofgc,g l21811l l-l i Oli 11 l 1/l I 013 I U l-l W

_ 22 23 24 26 27 28 29 30 31 32 T EN ACTO ON P NT vT *OyR$ S8 i 50 8. SL Li VANUFA RER l Al@h l@

33 34 lZl@

35 l Z lh ,l0 36 v l Ol0 lo40l [Y_j@

41

[X_jh 42

[Llh lEl0lAl5 lh 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 1iloiI I

,, ,,y; See Attached. I I i 17 I l l 1:131 L l l i 141 I l 7 8 9 80

's'TAEY vCwsR oT ER status h c'SEo?E0v' oiscovERv cEsCRiPTicN h NA Operator Observation l1 15 l l E l@ l1 l 0 l 0 l@l l [Bl@l l ACTIVITY CC TENT RELE ASED OF RELE ASE AMOUNT OF Activity LOCAtl0N OF RELEASE l1 168 9l W @ lZ l@l N/A l l N/A l 7 10 11 44 45 80 PERSONNEL EXPC%AES NUM8ER TYPE CESCRIPTION l i l 71 l 0 l 0 l 0 l@l Z'l@l NA l

' ' ' PERscNNd',N;uLs '

Nuv8eR oEsCR#TicN@

lilal1010101@l~

7 8 9 11 12 NA 80 I

Lossc cR ' ' 'oAvAcE

"" To,ACiuTv g e1122eo41e e11217 g,;3g gl g DR ADOCK 05000 l 7 6 3 13 80 tSR E DESCRIPTION *

[2101 l Ylbl Daily Status Phone (5/7.8 and 11/81) l lII!lll1II!III 7 8 3 to 69 69 80 5 W.P. M urphy (802)257-7711 o NAVE CF PREPARER PNCN E. $

. ~ . .- . .. .. .

s-VTVYS1

- > 05000271 UPDATE REPORT - Previous Report 6/3/81 LER 81-ll/3X -

1 CAUSE DESCRIPTION AND COFRECTIVE ACTIONS 4

The Reactor Water Cleanup System was . removed from service to l allow the degraded fitting to be replaced with an identical spare.

! The fitting was- sent to an independent laboratory where the mode of failure was determined to be intergranular stress corrosion crack-ing. During the 1981 refueling outage, this fitting and all similar fittings in the RWCU System were replaced with a differently designed.

reducing fitting which is less susceptible to this type of failure.

The laboratory analysis also revealed transgranular stress corrosion 4 cracking (not through wall) adjacent to the subject through wall crack on

the OD of the pipe. - The transgranular cracking was attributed ' to the

wetting of asbestos insulation with subsequent. leaking of chlorides to

the pipe surface.

As a result of this event and other transgranular cracking events, a- detailed plant review was performed to . determine if any other . insulated'

~

high temperature stainless steel lines.have been subjected to wetting.

In addition, a field walkdown was performed to' identify sources or

! potential sources of wetting. .As a result of this. review, only the sus-  !

I pect piping and fittings in the, RWCU System were replaced during the 1981

• efueling outage. . ,

J

. Any future wetting will be followed-up byfinspections as required.

Purchase of all insulation and application of protective paints will be 4

continued with the emphasis on chloride control. Impicmentation of the-i aforementioned program and controls will reduce the potential for any.

future stress corrosion cracking.

l-i i

i i

i

- . - -- -- -_- - . - . - - - - . . _ . ._ _ _ - - . . _ . .- - . -.