ML18153C626

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LER 91-008-00:on 910425,two Main Control Room/Emergency Switchgear Room Chillers Declared Inoperable.Caused by Failure of Reset Relay for Oil Pressure/Overload Trip.Edg Returned to Svc & Relay installed.W/910522 Ltr
ML18153C626
Person / Time
Site: Surry Dominion icon.png
Issue date: 05/22/1991
From: Kansler M
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
91-298, LER-91-008-01, LER-91-8-1, NUDOCS 9105300145
Download: ML18153C626 (5)
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  • Virginia Electric and Power* Company Surry Power Station P. 0. Box315 Surry, Virginia 23883 May 22, 1991 U. S. Nuclear Regulatory Commission Serial No.: 91-298 Document Control Desk DocketNos.: 50-280 Washington, D. C. 20555 50-281 License Nos.: DPR-32 DPR-37 Gentlemen:

Pursuant to Surry Power Station Technical Specifications, Virginia Electric and Power Company hereby submits the following Licensee Event Report for Units 1 and 2.

REPORT NUMBER 91-008-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be reviewed by the Corporate Management Safety Review Committee.

Very truly yours, M. ansler Station Manager Enclosure cc: Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323

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NRC FORM 366 (6-89)

LICENSEE EVENT REPORT (LERI U.S. NUCLEAR REGULATORY COMMISSION

  • APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) I PAGE (3)

Surry Power Station, Unit 1 I 01s101010121 s, ol, loF 014 TITLE <4l Two Main Control Room/Emergency Switchgear Room Chillers Inoperable Due to Relay Failure and Inoperable Emergency Power Source EVENT DATE (5) LER NUMBER (6) REPORT DATE (71 OTHER FACILITIES INVOLVED (Bl_

MONTH DAY YEAR YEAR ft: sez~~~~~AL }( ~~t~~~ MONTH DAY YEAR FACILITY NAMES DOCKET NUMBER(SI Surry Unit 2 o I 5 Io I o I o 1 21 8 1l OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE R~QUIREMENTS OF 10 CFR §: /Check one or more of th* following/ (111

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MODE (81 POWER L~1~~L I

~ - - - - - -....~ - - - l 1I

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20.402(bl 20.406(11(1)(i) 20.406(11(11(i1) 20.405(cl 50.381cll11 50.38lcll21 50.7311112llivl 50.7311112lM 50.73(111211vii) 73.711b) 73.711c)

OTHER (Specify in Abstract below and in Text, NRC Form lllllllll=

20.406(1111 lliiil X 50.73111121(i)

,....._ 50.7311112llviiillA) 366A) 20.405(1111 )(Iv) 20.405111111M - 50.7311112lliil 50.7311112lliiil

,....._ 50.7311ll2)lviiillB) 50.7311) l211x)

LICENSEE CONTACT FOR THIS LER 1121 NAME TELEPHONE NUMBER AREA CODE M. R. Kansler, Station Manager 81014 315171-13111814 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 113)

MANUFAC* MANUFAC-CAUSE SYSTEM COMPONENT TURER TURER X 1R1L jY I I I N I I I I I I I I I I I I I I I I I I I I I SUPPLEMENTAL REPORT EXPECTED 1141 MONTH DAY YEAR EXPECTED SUBMISSION h YES (If y*s, comp/et* EXPECTED SUBMISSION OATEJ DATE 115)

I I I ABSTRACT (Limit to 1400 spaces, i.*.* approximately fifte*n sing/s,spac* typewritten lin*sl 116)

On April 25, 1991, with Unit 1 operating at 100% power and Unit 2 in Refueling Shutdown, Main Control Room/Emergency Switchgear Room (MCR/ESGR) Chiller 1-VS-E-4A tripped and could not be restarted. The chiller was declared inoperable at 2255 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.580275e-4 months <br />. With Chiller 1-VS-E-4A inoperable, Technical Specification 3.0.2 no longer allowed Chiller 1-VS-E-4B to be considered operable because its emergency power source was out of service. With two of three MCR/ESGR chillers considered inoperable, a condition not allowed by Technical Specification 3.23 existed and an action statement requiring Hot Shutdown within six hours was entered in accordance with Technical Specification 3.0.2. A power decrease was begun on April 26, 1991 at 0115 hours0.00133 days <br />0.0319 hours <br />1.901455e-4 weeks <br />4.37575e-5 months <br /> and a Notification of Unusual Event (NOUE) was declared. The problem with the "A" Chiller was determined to be a failed oil pressure/overload reset relay. The oil pressure/overload reset relay from the "B" Chiller was installed in the "A" Chiller and the "A" Chiller was declared operable at 0222 hours0.00257 days <br />0.0617 hours <br />3.670635e-4 weeks <br />8.4471e-5 months <br />. The power decrease was stopped and the NOUE terminated at that time. No significant safety consequences resulted from the event. An upgrade of the MCR/ESGR Air Conditioning System is in progress and will include the installation of two additional 50% capacity chillers. This report is required by 10 CFR 50.73(a)(2)(i)(B).

NRC Form 366 16-89)

l',lr\~ t-UHM ~bbA U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92

  • MATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE E V . REPORT (LER) 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 THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

Surry Power Station, Unit 1 o 15 Io Io Io 1 21 810 91 1 - 0 IO I 8 - 0 p OJ 2 OF O I 4 TEXT (If man,_.,. i8 ,aquil9d, u11t1 additional NRC Fann 356A'a) (17)

1. O DESCRIPTION OF THE EVENT On April 25, 1991, Unit 1 was operating at 100% power and Unit 2 was in Refueling Shutdown for a scheduled outage. Main Control Room/Emergency Switchgear Room (MCR/ESGR) Chillers (EIIS-VI-CHU) 11 11 11 11 1-VS-E-4A, l-VS-E-4B, and 1-VS-E-4C were operable with the A and B Chillers in operation. Emergency Diesel Generator (EDG) (EIIS-EB,DG)

No. 3 was out of service for maintenance. Control Room Operators 11 11 noticed during routine control board monitoring that the A Chiller was not loading as expected. An operator dispatched to the local chiller control panel discovered that an oil pressure/overload trip signal was present and would not reset. The A Chiller was declared inoperable at 11 11 2255 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.580275e-4 months <br />. The B" Chiller's emergency power source (EDG No. 3) was 11 11 out of service and Technical Specification 3.0.2 allowed the B Chiller to 11 be considered operable only if its redundant trains were fully operable (including normal and emergency power sources). With the A Chiller 11 11 II inoperable, the "B Chiller could no longer be considered operable.

Technical Specification 3 .23 requires that MCR/ESGR Chillers 1-VS-E-4A, 1-VS-E-4B and 1-VS-E-4C be operable when either unit is above Cold Shutdown. Technical Specification 3.23 permits one chiller to be inoperable for a maximum of seven days but does not address two or II three chillers being inoperable. With the A" Chiller inoperable and 11 the "B Chiller's emergency power source out of service, a condition not addressed by Specification 3.23 existed and an action statement requiring Hot Shutdown within six hours was entered at 2255 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.580275e-4 months <br /> in accordance with Specification 3.0.2.

At 0115 hours0.00133 days <br />0.0319 hours <br />1.901455e-4 weeks <br />4.37575e-5 months <br /> on April 26, 1991, a power decrease was begun. In accordance with Emergency Plan Implementing Procedures, a Notification of Unusual Event (NOUE) was declared due to the mode reduction required by Technical Specifications. Required Emergency Plan notifications were made to state and local governments by 0124 hours0.00144 days <br />0.0344 hours <br />2.050265e-4 weeks <br />4.7182e-5 months <br /> and to the Nuclear Regulatory Commission by 0140 hours0.00162 days <br />0.0389 hours <br />2.314815e-4 weeks <br />5.327e-5 months <br />.

11 The problem with the A Chiller was determined to be the reset relay 11 (EIIS-VI,RL Y) for the oil pressure/overload trip. A replacement relay was not available on site, so the relay from the B Chiller was removed 11 11 11 11 and installed in the A Chiller. The "A Chiller was tested with 11 satisfactory results. A meeting of the Station Nuclear Safety and Operating Committee (SNSOC) was held to review the actions taken and 11 additional proposed actions. With SNSOC concurrence, the "A Chiller NRC Fann 3116A IIM19)

NH(.; FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB No: 3150-0104

'"' J EXPIRES: 4/30/92

.. MATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE E A REPORT (LER) 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 THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

SEQUENTIAL ::::::::::: REVISION YEAR -:::::::::: NUMBER  :::::::::: NUMBER Surry Power Station, Unit 1 o Is I o I o I o I 21 8 I o 911 - o 10 I 8 - oI o oI 3 OF o I4 TEXT (ff,,.,,,. .,.,,,, i8 -,ui,ed, use additional NRC Fann 31156A :0) (17) was declared operable at 0222 hours0.00257 days <br />0.0617 hours <br />3.670635e-4 weeks <br />8.4471e-5 months <br />. Since the "A" and "C" Chillers and their respective emergency power sources were operable at that time, the_ six hour action statement to Hot Shutdown was exited, the power decrease was stopped, and the NOUE was terminated. A seven day action statement was entered in accordance with Technical Specification 3.23 due to the "B" Chiller being inoperable. Notification of the NOUE termination was made to state and local governments by 0234 hours0.00271 days <br />0.065 hours <br />3.869048e-4 weeks <br />8.9037e-5 months <br /> and to the Nuclear Regulatory Commission by 0235 hours0.00272 days <br />0.0653 hours <br />3.885582e-4 weeks <br />8.94175e-5 months <br />.

This report is required by I0CFR50.73(a)(2)(i)(B) since the station was operated in a condition not allowed by the Technical Specifications.

2. O SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS Chillers l-VS-E-4A, 1-VS-E-4B, and 1-VS-E-4C are part of the MCR/ESGR Air Conditioning System. This is a shared system designed to maintain the Unit 1 and Unit 2 MCR and ESGRs at or below design temperatures during normal operation and design basis accident conditions. Two chillers are required to operate in order to remove design heat loads, assuming worst case ambient air temperature and service water temperature.

With the "A" Chiller inoperable and the "B" Chiller's emergency power source out of service, two chillers ("B" and "C") would still have been available under accident conditions provided off site power were available. Without off site power, only the "C" Chiller would have been available; however, temperature rise in the MCR and ESGRs would have been limited in an accident situation since service water temperature was below that assumed in design calculations.

Actual MCR and ESGR temperatures were not observed to increase during the event. It is concluded that no significant safety consequences resulted from the event.

3.0 CAUSE OF THE EVENT The event was caused by failure of the reset relay for the oil pressure/overload trip in the "A" Chiller. This relay is energized during normal chiller operation. The relay is de-energized when compressor oil pressure is less than approximately 30 psig above suction pressure, causing a compressor trip and preventing the chiller from restarting and loading. The relay coil failed due to age-related degradation.

NRC Form 386A (IMl9)

hit\/.; rOHM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92

  • MATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE E . REPORT (LER) 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, WASHIN!3TON, DC 20555, AND TO l'HE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME Cl) DOCKET NUMBER 12) PAGE 13)

LER NUMBER (6)

SEQUENTIAL ;
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; REVISION YEAR  :;:;:;:;:;: NUMBER  ;:::;:;:;: NUMBER Surry Power Station, Unit 1 0 1s I O I O I O I 21 8 10 9 11 - 0 I 01 8 - 0 IO O14 OF O I4 TEXT (H mom-= is n,quimd, Ulf<I *dditla111JI NRC Form 3IIS4 'a) 117) 4.0 IMMEDIATE CORRECTIVE ACTION

When a replacement for the failed reset relay could not be obtained on site, the "B" Chiller was removed from service and its oil pressure/overload reset relay was installed in the "A" Chiller. The "A" Chiller was tested and confirmed to be fully operable with satisfactory oil pressure. The "A" Chiller was returned to service at 0222 hours0.00257 days <br />0.0617 hours <br />3.670635e-4 weeks <br />8.4471e-5 months <br /> on April 26, 1991.

5. O ADDITIONAL CORRECTIVE ACTION{S}

Emergency Diesel Generator No. 3 was returned to service on April 27, 1991 at 1243 hours0.0144 days <br />0.345 hours <br />0.00206 weeks <br />4.729615e-4 months <br />. A replacement oil pressure/overload reset relay was obtained for the "B" Chiller. The relay was installed and the Chiller tested with satisfactory results. The Chiller was returned to service on April 28, 1991 at 1001 hours0.0116 days <br />0.278 hours <br />0.00166 weeks <br />3.808805e-4 months <br />.

6. 0 ACTIONS TO PREVENT RECURRENCE An upgrade of the MCR/ESGR Air Conditioning System is in progress.

The upgrade will include the installation of two additional 50% capacity chillers. These additional chillers will increase operational flexibility and improve the capability to withstand single failures.

7. 0 SIMILAR EVENTS Licensee Event Report 1-86-027: With MCR/ESGR Chiller 1-VS-E-4A out of service for maintenance, Chiller 1-VS-E-4B tripped and would not restart due to a failure of its low refrigerant temperature cutout relay.

This was considered to be an isolated incident and no corrective action beyond replacement of the failed relay was taken.

8.0 ADDITIONAL INFORMATION Failed Components:

RBM Controls 208/230 VAC Relay Model No. 129110-6830ZC NRC Fonn 368A (6-89)

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