ML19269C171

LER 78-068/03L-0 on 781220:during Normal Operation W/A Recirculation Pump Suction Valve OOS Open,Breaker for Pump Discharge Bypass Valve Thermally Tripped.Probable Cause Was Dry Packing Leading to Thermal Overload

ML19269C171
Person / Time
Site:	Dresden
Issue date:	01/18/1979
From:	Coen R COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17173A554	List: ML17173A553 ML19269C171
References
LER-78-068-03L, LER-78-68-3L, NUDOCS 7901290265
Download: ML19269C171 (3)

Text

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• LICEi4SEE EVENT REPORT CONTRCL GLOCK: l I I, l la l l o

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REPOR i DATE 7 8 00 61 DOCKET NU*.1B E R EVENT DESCRIPTICfJ AND P70BABLE CCNSEQUENCES h ol2 lDuring normal operation with "A" cecire pump suction valve 00S open, breaker for pump g 3 j discharge bypass valve was fotad thermally tripped. Had LPCI injection into A loop l o a l been required durina, hypothetical accident, small reduction of flow to reactor could I l

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0 3 gg SY S T E11 CAUSE CAUSE C C F.* P. VALVE CCDE CODE SU3 CODE CO'JPONENT CODE SUSCCCE SUBCOOE o 9 l C l B lh lE l@ [Blh 9 40 11 12 IJ Vl Al Ll V El x lh l E lh [D_] h Id 19 20 7 8

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_ 21 ATT ACHY E NT N P R D -4 PRIVE CC'lP. CO'.*PO N PJ T ACTION FUTUn! EFFECT SH U TO Oi/N T A k.E N AC!iDN ON PLANT PJETHOD HOURS SUS ?.1I T T E D F OR ?.1 :iU B. SUPP LI E R MANUFACTURER IX l@lJ4 xi@

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3a 36 zl@ l 01 O! 0 01 J/ 40 41 Yl@ l42 N ih lNh 43 44 Cl6l6l5lh 47 CAUSE CESCRIPTION AND CCRRECilVE ACTICfJS h ilo lLater tests found no anomalies with valve operation. Since valve is infrequent 1v usedl i i probable cause was dry packing which led to thermal overload. Packing and sten will I be lubricated during next refueling outage, g l

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/ 8 9 ST 3 *'. POWER OTHER STATUS ISCOV FY DISCOVERY DESCRIPTION 7

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• NU'.'R E H DESCRIPTION

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• DEVIATION REPORT DV R NO.

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78 - 131 PART 1 TITLE OF DEVIATION OCCU RRED 12-20-78 1545 Recirc pump discharge bypass valve DATE TIME SYSTEM AFFECTED PLANT CONDITIONS TESTING Recirculation Syst. 202 MODE Run gwg,g ,7)

U% , LOAD (MWE) NO

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DESYRIPTION OF LVEN!

2A.recirc pp, disch bypass valve (2-202-7A) was found thermally tripped. Valve open at the time To relieve 4" bypass stagnation problem DESCRIPTION OF CAUSE Unknown

'OTHER APPLICABLE INFORMATION Breaker was reset ok EQUIPMENT YES DR NO. WR NO.

FAILU RE NO NA NA R. Holman 12-20-78 PESPONSIBLE SUPERVISOR DATE PART 2 OPERATING ENGINEERS COMMENTS B Recire loop was available for injection by LPCI, with all valves operable. This is also the preferred inlection loop. Some bypass flow would occur thru the 7A valve (4") if A loop were selected for injection. However, this should be saall in comparison to size of LPCI injection SAFETY-TYPE OF CEVIATION EVENT OF POTENTIAL TECH SPEC NON-REPORTABLE ANNUA _ RELATED REPORTABLE OCCURRENCE PUBLIC INTEREST VIOLATION OCCURPENCE REPORTING WR ISSUED 14 DAY 10CFR21 YES X YES X 30 DAY NOTIFICATION NO NO X 6.6.B.2.h REPORTABLE CCCURRENCE ACTION ITEM NO. PROMPT CN-SITE NOTIFICATION

" U A. Roberts Asst. Supt. 12/22/78 1300 h ' 68 03L-0 NA NA TITLE DATE TIME TITLE CATE TIME 24-HOUR NRC NOTIFICATION PROMPT OFF-SITE NOTIFICATION NA F. Palmer 2:18 TPH 12/22/78 REGION 111 DATE TIME TITLE DATE TIME TGM NA J.R. Gilliom 12/22/78 2:18 REGION lit a COL PATE TIME TITLE DATE TIME RESPONSI BLE COMP ANY OFFI CER INFORMED OF 10 C FR 21 CONDITIONS AND THEI R REPORT TO NPC + TITLE DATE TIML J.S.Kolanowskih/dd,

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REVIEW AND COMPLETED , 12/22/78 OP E R Al l NG ENG l[fE Lrt DATE BY STATION REVI %

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RESOLUTION APPROVED AND C W /~O-79 AUTHORIZED FOR DISTRIBUTION ' ~ STATION' SUPERINTENDENT DATE ela5!76 10-77 (Fonu 15*52-t) ,

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J tN 2 41979

OPDIATI?;G E GI!EERS CO 01E:;TS ,

line (16") . All four LPCI pumps were available for injection with only three required for design 14,500 GPM flow. Recire pump suction valves are open and prevented from closing by racking out breaker per G.E. & !;RC recommendation to prevent hypothesized suction valve closure.

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ATTACHMENT TO LICENSEE EVENT REPORT 78-68/03L-0 COME:NEALTH EDISON COMPANY (CWE)

DRESDEN UNIT-2 (ILDRS-2)

DOCKET #050-237 During noren1 operation with "A" recirc pump suction valve out-of-service in the open position, the breaker for the bypass valve around the recirc pump discharge valve was found thermally tripped after the valve opened. The recirc pump suction valves are presently normally kept 00S in the open position to elimin-ate the possibility of a spurious closure of the valve during a hypothetical los -of-coolant accident. The recirc pump discharge bypass valves are nor-mally open to prevent stagnation of the water in the bypass line, but the valve had been closed and reopened after an earlier recire pump trip.

The low pressure coolant injection system would normally inject into the "B" recirc loop during a loss-of-coolant accident, and this loop was un-affected by this event. However, with this breaker tripped, had the low pressure coolant injection (LPCI) loop-select logic system been required to select the "A" recirc loop for LPCI injection, the bypass valve would not have shut upon signal and some of the LPCI flow could have been di-verted backwards through the bypass valve, the recirc pump, and its suction valve, into the core annulus region.

Calculations indicate that the flow from the 16 inch diameter LPCI injection line which might have been diverted through the 4 inch diameter bypass valve line was minor. Approximately 2800 gpm could conservatively have been diverted. All four LPCI pumps were operable and each pump is rated at 6000 gpm. Technical Specifications require three LPCI pumps to be operable to deliver the design required 14,500 gpm LPCl flow.

Later testing could not identify any discrepancies with the operation of the bypass valve. Since the valve is infrequently used, the probable cause was dry packing which affected the opening torque and caused the thermal overload condition. Subsequent cycling probably lubricated the packing such that the problem did not reoccur. The valve stem will be lubricated during the next refueling outage. -

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