ML18153C012

LER 89-042-00:on 891031,leak Detected Through Crack in Fillet Weld on Socket Tee Connecting Drain Line to Letdown Line Which Exceeded Allowable Type C Leakage.Caused by Vibration.Line & Valve Configuration changed.W/891128 Ltr

ML18153C012
Person / Time
Site:	Surry
Issue date:	11/28/1989
From:	Kansler M VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
89-055, 89-55, LER-89-042, LER-89-42, NUDOCS 8912140165
Download: ML18153C012 (4)

Text

-* e **

VIRGINIA ELECTRIC AND POWER COMPANY Surry Power Station P.O. Box 315 Surry, Virginia 23883 November 28, 1989 U.S. Nuclear Regulatory Commission Serial No.: 89-055 Document Control Desk Docket No.: 50-280 Washington, D.C. 20555 License No. : DPR-32 Gentlemen:

Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Unit 1.

REPORT NUMBER 89-042-00 This report bas been reviewed by the Station Nuclear Safety and Operating

• Comaittee and will be reviewed by Safety Evaluation and Control.

Very truly yours, Station Manager Enclosure cc: Regional Administrator

• Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323

3*;,1128 ~

~bR~

1 '">14(>1/.

AfiOCK CO'.

05000280

.poc

NRC Form 381 19-831

-* LICENSEE EVENT REPORT (LERI e ** POW 28-06-01 U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3160--011),t EXPIRES: 8/31/88 FACILITY NAME 111 DOCKET NUMBER 121 I PA<iE 131 Surry Power Station, Unit 1 Io Is Io , o Io 12 18 I OI , loFI O13 TITLE 1,1 Leakage Through Fault in Letdown System Drain Line in Excess of Allowable Tvoe "C" Leakage

___ Ev_E_N_T_D_A_T_E_n_11_ -t----~~LEr.:R=NU-;;M;-::.B;:;:E-;-:R:--:-l"T61:,:,:,:,:or:::=~l-___..:R.:..:E:;,.l'O..:..:..:.RT.:..::DA:.T;,:E:..:<.:..:71_-'-_ _ _ _ __:o::T:.:.H::E::R..:F.=Al:IL TIES INVOLVED 1111 MONTH OAV YEAR YEAR .)? SE~~~~~~AL }( ~~1~~~ MONTH DAV VEAR FACILITY NAMES DOCKET NUMBERISI 11 o ~ 1 8 9 819 - o 14 I2 - 01 o 111 2 I8 81 9 Ol'ERATINO THII REPORT IS IUIIMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: /Ch.r:lt on* or mo,. of th* follo'l(in11J 1111 I*

N 11---MOO--E-,C"'"ll---'--+-1 20.'°2Cbl

...._ 20.40IICcl * - II0.73C1112Hivl

-- 73.71lbl POWER 20.40IIC1111 ICII II0.38Ccll1 I II0.73C1HZIM 73.711*1 L~~~L 1 I O 10

- 20.40IIC11C1ICIII - II0.311Ccll21 a-- II0.73C11C21Cvill OTHER /S,,.,:lfy in Ab,rr.cr

-x Wlaw and in T*xr, NRC Farm iiiiii~ 20.40IIC1111111111 II0.73C11121CII II0.73C11C2HvilllCAI 366A}

20.40ll(1ll11Clvl II0.73111C21Uil II0.73(11(21Cv111IIB1 20.40lll1ll1 IM II0.73CalCZIIIIII II0.7311112Hxl LICENIEE CONTACT FOR THIS LER 1121 NAME TELEPHONE NUMBER AREA CODE M. R . Kansler, .Station Manager 81 0 14 31 5 I 7 r I 3 I l 18 14 COMPLETE ONE LINE FOR EACK COMPONENT FAILURE DESCRIIIED IN THI!! REPORT 1131 CAUSE SYSTEM COMPONENT MANUFAC-TURER I I I I I I I I I I I I I I I-,

~

I . I I I I I I IUl'PLEMENTAL REPORT EXPECTED 11'1 I I I I I I EXPECTED I

I ;.~v,*ITH I 0"'" I YEAR

.-;-..;._____i...- -

~  !

SUBMISSION I

. I*:*::: .. ;.; ra, _ , _ /il(PECTED SIJIJM/SS/ON DATE} NO I n!'..,TI; 11~!

I I I I I I On October 31, 1989 with Unit 1 at 100% power following indications of an increased Reactor Coolant System leak rate, operators entered containment to identify the source of leakage~ A leak was detected through a crack in a fillet weld on a socket tee connecting a. drain line to* the letdown line. Since the leak was located between the inside containment letdown ~rip valves and the containment wall a containment integrity concern was identified and a six hour action statement to hot shutdown was entered. An engineering calculation estimated the containment Type "C" leakage to be in excess of the allowable. The crack was attributed to cyclic fatigue resulting from *the drain li_ne co_nfiguration and line vibration. Excess letdown was placed in service, and the outside containment letdown isolation valve was closed to establish containment integrity. The faulty weld, drain line and drain valve were removed and a capped pipe nipple was installed in the socket tee in place of the drain line. As a permanent repair, the drain line and valve_ will be installed in a different configuration to minimize the vibration effects.

fl!RC FORM 366A U.S. NUCLEAR REGULATORY COMMI (6-891 APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LEA) INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-5301. U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON, DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (3150-01041, OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (11 DOCKET NUMBER (21 LER NUMBER (61 PAGE (31 -

Surry Power Station, Unit 1 o 5 Q o Q 2 8 0 8 9 _ 0 4. 2 _ 0 0 0 2 OF O 3 1.0 Description of the Event On October 31, 1989 at 0514 hours0.00595 days <br />0.143 hours <br />8.498677e-4 weeks <br />1.95577e-4 months <br />, with Unit 1 at 100%

power, it was determined that the Reactor Coolant System (RCS) (EIIS-AA) unidentified leak. rate had increased above the leak rate measured on the previous day. However, it remained within the limits specified, in the Technical Specifications (T.S.). At 1048 hours0.0121 days <br />0.291 hours <br />0.00173 weeks <br />3.98764e-4 months <br />, a containment entry was made and leakage was observed in the vicinity of a drain valve (EIIS-V) in the letdown system (EIIS-B) downstream of three parallel letdown orifice isolation valves (HCF-CH-1200A, B, C) (EIIS-ISV). A valve packing leak was suspected. Since the drain valve is located between th~ letdown orifice isolation valves (inside containment letdown trip valves) and the containment wall (EIIS-NH), a containment integrity concern was determined to exist and a six hour action statement to hot shutdown was entered at 1115 hours0.0129 days <br />0.31 hours <br />0.00184 weeks <br />4.242575e-4 months <br /> per Technical Specification 3.0.1. The six hour action statement was exited at 1323 hours0.0153 days <br />0.368 hours <br />0.00219 weeks <br />5.034015e-4 months <br /> when excess letdown (EIIS-CB) was placed in service and the outside containment letdown isolation trip valve, TV-CH-1204, (EIIS-ISV) was closed .. No power reduction was required.

• An engineering calculation estimated the Type "C" leakage from the drain valve as 239. 45 S.tandard Cubic Feet Per Hour (SCFH) which is the excess of the total allowable containment leakage of 180 SCFH.

2. 0 s*afety Consequences and Implications The letdown system inside and outside.containment isolation valves provide redundant containment isolation capability in the event of a loss of reactor coolant accident. During this event, the outside trip valve, TV-CH-1204, remained operable and would have provided containment isola-tion if required.

Therefore, the health and safety of the public were not affected.

• 3.0 Cause Subsequent containment entries determined that the increased RCS leakage was not due to a packing leak on 1-CH-427, but due to a crack in a fillet weld on a socket tee (EIIS-PSF) connecting th~ 3/4" drain line NRC Form 368A (IM!9l

- 1 IILRC FOHM 366A U.S. NUCLEAR REGULATORY COMMI (6-89) APPROVED.OMB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LERI INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530). U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 20555. AND TO 1'HE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME 11) DOCKET NUMBER (2) . LER NUMBER (8) PAGE (3)

Surry Power Station, Unit 1 O 5 O O o 2 8 0 8 9 _ 0 4 2 _ 0 0 0 3 OF O 3 TEXT /ff mo,e :,pace~ ,aqund, u* MldltiaMI NRC Fann 3156A'*! (17) containing the drain valve to the letdown line. The failure has been attributed to cyclic fatigue resulting from the drain line configuration *and line vibration.

4.0 Immediate Corrective Action(s)

A six hour action statement to hot shutdown was entered when the containment integrity concern was identified.

5.0 Additional Corrective Action(s)

Excess letdown was placed in service, normal letdown was secured and the outside containment letdown isolation valve, l-CH-TV-1204, was closed to establish containment integrity. As an interim repair, the faulty weld,- drain line and valve were removed and a capped pipe nipple was installed in the socket tee in place of the drain line.

6.0 Action(s) Taken to Prevent Recurrence

. As a permanent repair, the drain line and valve .will be installed in a different configuration to minimize the vibration effects.

7.0 Similar Events LER 86-023, Unit 1: Containment sump inside trip valve had excessive leakage through the packing gland.

Technical Specification 3.0.1 was entered and the manual isolation valves for the trip valve were closed t'o satisfy containment integrity. The valve packing follower was tightened and leakage - was reduced to acceptable levels.

LER 88-002, Unit 1: Reactor coolant cold leg sample isolatio*n valves' leak rates were greater than*

allowable leak rates. The valves were maintained closed and placed under administrative control by lifting the solenoid valve leads to satisfy containment integrity.

8.0

• Manufacturer/Model Number(s)

N/A NRC Form 368A (6-89)