ML18150A252

LER 87-013-00:on 870623,unit Shutdown Commenced Due to High RCS Leak Rate.Caused by Failed Packing on Loop Stop Valve MOV-1593.Loop Stop Valves Repacked & Diaphragm on Drain Header Isolation Valve replaced.W/870723 Ltr

ML18150A252
Person / Time
Site:	Surry
Issue date:	07/23/1987
From:	BENSON D A VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
87-015, LER-87-013-01, NUDOCS 8707290023
Download: ML18150A252 (4)

Text

.. NRC Form 366 19-83) FACILITY NAME (1) LICENSEE EVENT REPORT (LER) POW 28-06-01 U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB. NO. 316CMl1D4 EXPIRES: 8/31 /88 Surry Power Station, Unit 1 'DOCKET NUMBER 12). I PAGE 131 0151010101218 10 1 loF 013 TITLE 14) High Reactor Coolant System Leak Rate Due to Failed Packing on Loop Stoo Valves . EVENT DATE 16) LER NUMBER 16)

• REPORT DATE 17) OTHER FACILITIES INVOLVED (BJ MONTH DAY YEAR YEAR tt SE~i~~i~AL MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISJ o I 5 I o 10 I O I I I o 16 213 a 1 a 11 -o I 1 13 -o Io o I 1 2 s 11 OPERATING MODE (8) THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check ona or more of tho follolf(ing/

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LICENSEE CONTACT FOR THIS LER 112) NAME TELEPHONE NUMBER AREA CODE D. A. Benson , Station Manager COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 113) CAUSE SYSTEM COMPONENT TURER TURER X 4.1 i:=! I I c;; IV I A I~ I Q 11 y I I I I I I I X Al i:=! I In I VI G 12 15 17 N I I I I

• I I . I .SUPPLEMENTAL REPORT EXPECTED 114) MONTH DAY YEAR n YES /If yss, complata EXPECTED SUBMISSION DATE/ rv, NO EXPECTED SUBMISSION DATE 115) I I

• I AilSTRACT (Limit to 1400 ,,,acss, i.* .* approximotaly fif~n single-sp11ca typawrlmn lines/ 118) On June 23, 1987 at 1532 hours0.0177 days <br />0.426 hours <br />0.00253 weeks <br />5.82926e-4 months <br />, with Unit 1 at 100% power, a unit shutdown was corrunenced due to an unidentified Reactor Coolant System (RCS) {EIIS-AB}

leak rate of 47 gpm. This event is contrary to Technical Specification 3.1.C.3 which limits unidentified RCS leakage to less than 10 gpm, and an unusual event was declared.

At 1628 hours0.0188 days <br />0.452 hours <br />0.00269 weeks <br />6.19454e-4 months <br />, a containment walkdown was conducted and operators subsequently placed the loop stop valves onto their backseats.

This reduced the unidentified RCS leak rate to .88 gpm, and the unusual event was terminated at 1924 hours0.0223 days <br />0.534 hours <br />0.00318 weeks <br />7.32082e-4 months <br />. The cause of the high RCS leak rate was failed packing on loop stop valve (EIIS-ISV}

MOV-15930 Additionally, due to the increased temperature and pressure in the packing drain header, the diaphragm ruptured on the drain isolation valve {EIIS-LOV}

1-DG-14. Subsequently, the unit was placed in cold shutdown and the loop stop valve was repacked.

The diaphragm on the drain header isolation valve was replaced.

9707290023 s~~g 00 PDR ADDCK O PDR s ([d \ I I NRC Form 316 (9-83)

NRC Farm 3118A (9-83) FACILITY NAME C1)

• e LICENSEE EVENT REPORT (LERI TEXT CONTINUATION POW 28-06-01 U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 3150-0104 EXPIRES: B/31 /88 DOCKET NUMBER 121 LER NUMBER (61 . PAGE 13) Surry Power Station, Unit 1 o 1s I o Io Io 12 1 a I o a, 1 -o 1 113 -o Io o 1 2 oF 01 3 TEXT (H --it,.,,,.,.,,, ,,_ eddltioM/

NRC Fann .-..'*I (17) 1.0 riescription of the Event On June 23, 1987 at 1532 hours0.0177 days <br />0.426 hours <br />0.00253 weeks <br />5.82926e-4 months <br />, with Unit 1 at . 100% power, a unit shutdown was conunenced due to a high Reactor Coolant System (RCS) {EIIS-AB}

leak rate. The leak*rate (not including leakage from controlled sources) was determined to be 47 gpm. This event is contrary to Te~hnical Specification.(TS) 3.1.C.3 which limits RCS leakage from other than controlled sources to 10 gpm.

• A notification of *an *unusual event was

• declared at 1532 hours0.0177 days <br />0.426 hours <br />0.00253 weeks <br />5.82926e-4 months <br /> due to the shutdown required by T. s. Limiting Condition for Operation (LCO). At 1628 hours0.0188 days <br />0.452 hours <br />0.00269 weeks <br />6.19454e-4 months <br />, a containment walkdown was

• conducted to identify the source of the leakage. During the walkdown, leakage was observed from the packing gland of.loop stop valves, MOV-1590 and MOV-1591 {EIIS ISV}, and it wa,s determined that a *drain header isolation valve.1-DG-14

{EIIS LOV} to the primary drains transfer tank had a .ruptured diaphragm.

Operators placed all of the loop stop valves. onto their backseats.

At 1816 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.90988e-4 months <br />, the reactor was in the hot shutdown condition.

At 1910 hours0.0221 days <br />0.531 hours <br />0.00316 weeks <br />7.26755e-4 months <br />, the RCS leak rate *Was determined to be 2.28 gpm of which*0.88 gpm was unidentified.

The event was terminated at 1924 hours0.0223 days <br />0.534 hours <br />0.00318 weeks <br />7.32082e-4 months <br />. 2.0 Safety Conseguences and Implications A limited amount of leakage from the RCS is expected.

The threshold values are 1 gpm from unidentified sources and 10 gpm from other than controlled sources. These values are sufficiently low to ensure early detection of unidentified and excessive leakage. riuring this event, the normal charging system was in service and was able to make up for the excessive leakage. The source of the leakage was identified and the leak rate was returned to an acceptable value. Therefore, this event does not constitute an unreviewed safety question and*the health and safety of the public were' not affected.

---NRC FORM 366" (9,831 ** U.S.GPO: 1988*0*824*5381455 ,

NRC Form 388A 19-83) FACILITY NAME (1 l e e LICENSEE EVENT REPORT (LER) TEXT CONTINUATION POW 28-06-01 U.S. NUCLEAR REGULATORY.

COMMISSION APPROVED 0MB NO. 3150-0104 EXPIRES: 8/31/88 DOCKET NUMBER 12) LER NUMBER 16) PAGE (3) Surry Power Station, Unit 1 0 15 IO IO IO , 2 I s ,o s, 7 -q ,, 3 -0 IO O I 3 OF O J 3 TEXT (If mote -* ,..,,..,.,, -MldltJo,,e/

NRC Fann .mA'1J 117) NRC FORM 386A (9-83) 3.0 Cause At approximately 2240 hours0.0259 days <br />0.622 hours <br />0.0037 weeks <br />8.5232e-4 months <br />, while the reactor was in hot shutdown, each of the 6 loop stop valves was taken off the backseat, one at a time, in order to determine the source of the RCS leakage. At that *time it was determined that the packing had failed on loop stop valve MOV-1593 and that the ruptured diaphragm on 1-DG-14 was caused by the increased temperature and pressure iri the packing drain line. The leakage initially observed from the packing glands of MOV-1590 and MOV-1591 was due to backflow through their leak-off lines as a result of the packing failure on MOV-1593.

4.0 Immediate

Corrective Actions The loop stop valves were placed on their backseats reducing RCS leakage to an acceptable value. The unit was brought to hot shutdown.

5.0 Additional

Corrective Actions Subsequently, the unit was placed in cold shutdown and loop stop valve MOV-1593 was repacked.

The diaphragm on drain header isolation valve, 1-DG-14, was replaced~

6. 0 Actions Taken .to Prevent Recurrence The unit will be operated with the loop stop valves on their backseats to 1/16" deflection.

Operation of these valves in this manner has been approved by the manufacturer, Anchor-Darling.

7.0 Similar

Events Unit 2, LER 86-002. 8.0 Manufacturer/Model Number Loop Stop Valves -Anchor Darling/Drawing Nos.: 95-11778, 95-11779 1-DG-14 -Grinnel/NUS Spec. #146.

• U.S.GPO: 1986*0*624-538/455 July 23, 1987 U.S. Nuclear Regulatory Commission Document Control Desk 016 Phillips Building Washington, D.C. 20555 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY Surry Power Station P. 0. Box 315 Surry, Virginia 23883 Serial No.: Docket No.: Licensee No. : 87-015 50-280 DPR.-32 Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Surry Unit 1. REPORT NUMBER 87-013-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be revie-Ped by Safety Evaluation and Control. Very truly vours, fj~~ David L. Benson Station Manager Enclosure cc: Dr. J. Nelson Grace Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323