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LER 89-031-00:on 890723,discharge Pressure for Control Room/ Relay Room Air Conditioning Chiller Svc Water Pump Decreased & Chillers Tripped on High Condenser Discharge Pressure.Caused by Air Binding.Pump vented.W/890822 Ltr
	ML18153B865
Person / Time
Site:	Surry
Issue date:	08/22/1989
From:	Kansler M; VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
	89-032, 89-32, LER-89-031, LER-89-31, NUDOCS 8908290029
	Download: ML18153B865 (7)
	v • d • e

VIRGINIA ELECTRIC ANO POWER COMPANY Surry P_, Station P. 0. Box 316 Surry, Vir9ini* 23883 August 22, 1989 U.S. Nuclear Regulatory Commission Serial No.: 89-032 Document Control Desk Docket Nos.: 50-280 Washington, _D.C. 20555 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 89-031-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be reviewed by Safety Evaluation and Control.

Enclosure cc: Regional Administrator Suite 2900 101 Marietta Street, NW Atlanta, Georgia 30323

POW 28-06-01 NRC FORM 366 (6-891 e U.S. NUCLEAR REGULATORY COMMISSION e APPROVED 0MB NO. 3150-0104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LERI 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 (11 iDOCKET NUMBER (21 I PAGE (31 Surry Power Station, Units 1 and 2 01s101010121B1 01 , OF 016 TITLE (41 Charging Pump Service Water Pumps Air Bound and Control Room Chillers Trip After Air Entered the Service Water System EVENT DATE (51 LER NUMBER (61 REPORT DATE (71 OTHER FACILITIES INVOLVED (Bl MONTH DAV VEAR VEAR r:x SEQUENTIAL NUMBER t? REVISION NUMBER MONTH DAV YEAR FACILITY NAMES DOCKET NUMBER(SI 0 I5 Io Io Io I I I 01 7 2 13 8 9 8j9 - 0'13 11 - 010 018 21 2 Bl9 0 I 5 Io Io I o I I I

THIS REPORT IS SUBMITTED PURSUANT TO THE RcCUIREMENTS OF 10 CFR §: (Chock on* or mors of the follow;ng} (111 OPERATING MODE (9) N 20.402(bl

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50.73(11(2lliiil 50.73(11(211*1 LICENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER M. R. Kansler, Station Manager AREA CODE 8 I O14 31517 1-1311 I 814 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (131 REPORTABLE .;.;:,;. MANUFAC*

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SUPPLEMENTAL REPORT EXPECTED (141 MONTH DAV YEAR EXPECTED I YES /If yss, compl*t* EXPECTED SUBMISSION DATE/

ABSTRACT (Limit to 1400 s{Mces, i.e .. approximately fifte~n singfe-sp,4ce typewritten /in~s) (16) hi NO

- SUBMISSION DATE 1151 I I I On July 23, 1989 at 1747 hours0.0202 days 0.485 hours 0.00289 weeks 6.647335e-4 months , with Unit 1 at 100% power and Unit 2 at cold shutdown, following manipulation of a Service Water (SW) valve to the Unit 2 bearing cooling water heat exchangers, discharge pressures for the Control Room/Relay Room (CR/RR) air conditioning chillers 1 SW pumps and the Unit 1 and Unit 2 charging pump SW pumps decreased due to air binding in the pumps. The pumps were declared inoperable. Also, the two operating CR/RR chillers tripped on high condenser discharge pressure. This is contrary to Technical Specification 3.3.A.7 and 3.23.C. The cause of the event has been attributed to air entering the SW lines that supply the pumps. The affected pumps were vented and returned to service and the CR/RR chillers were returned to service. Additional high point vents are being installed. A procedure for periodic venting has been developed and the abnormal procedure for restoration has been enhanced. In addition, a design change being implemented to increase the size and number of SW supply lines to the pumps has provisions for appropriate vents to facilitate removal of entrapped air. Engineering is continuing their investigation of the event to determine if other actions are required.

NRC Form 366 (6-89)

NRC FORM 366A (6-89)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION 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 BURO EN 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) LER NUMBER (6) PAGE (3)

YEAR :::::::::: SEQUENTIAL ::::::::::: REVISION

NUMBER

::::::::: NUMBER Surry Power Station, Units 1 and 2 TEXT (ff man, lfPIJCtJ i& 1'9quited, usa *dditiona/ NRC Form 3156A'a) (17) 1.0 Description of the Event On July 23, 1989 at 1747 hours0.0202 days 0.485 hours 0.00289 weeks 6.647335e-4 months , with Unit 1 at 100%

power and Unit 2 at cold shutdown, 2-SW-MOV-201B, a Service Water (SW) (EIIS-ISV) supply valve to the Unit 2 Bearing Cooling Water Heat Exchangers (BCHX)

(EIIS-HX) was manually opened for post maintenance testing. Immediately following this action, discharge pressures for the Control Room/Relay Room (CR/RR) air conditioning chillers' SW pumps and the Unit 1 and Unit 2 charging pump SW pumps (EIIS-P) decreased due to air binding in the pumps. The pumps were declared inoperable.

At the time of the event, the three CR/RR chiller SW pumps and the Unit 1 "B" and Unit 2 "A" charging pump SW pumps were operating. The Unit 1 "A" and Unit 2 "B" charging pump SW pumps were in standby and automatically started in response to the low pressure condition. However, the low pressure condition did not clear. Also, as a consequence of the lack of service water to the CR/RR chillers, the two operating chillers, "A" and "B", tripped on high refrigerant pressure.

A similar event had occurred on July 18 when 2-SW-MOV-201A, the redundant SW supply to the Unit 2 BCHXs, was being manually operated for testing. Due to this earlier event, added precautions were taken prior to the operation of the SW valve on July 23.

Operators were stationed at the charging pump SW pumps and radio communications were established between them and personnel operating the MOV. Personnel involved were given instructions to slowly open the MOV and immediately close it if pump discharge pressures began to drop. As an additional precaution, 2-SW-MOV-201A and 2-SW-11 (an alternate supply to the pumps) were verified closed to ensure no air could enter the in-service SW supply. Not withstanding these precautions, the pumps became air bound even though the valve was closed promptly when discharge pressure began to drop at the pumps.

The air intrusion rendered both Unit l's and Unit 2's charging pump service water pumps inoperable. This is contrary to Technical Specification 3.3.A.7. In NRC Form 366A (6-89)

NRC FORM 366A (6-891 LICENSEE EVENT REPORT (LER) e U.S. NUCLEAR REGULATORY COMMISSION e 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 TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P-530). 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 (2) LER NUMBER (6) PAGE (31 Surry Power Station, Units 1 and 2 0 I 5 I O I O I O I 2 18 I O 8 19 - 0 I 311 - 0 IO O13 OF O I6 TEXT (" more S{J(Jce i& raquirrtd, uss additional NRC Form 31511:A '*I 1171 addition, due to the lack of service water supply to the CR/RR chillers, they were declared inoperable.

This is contrary to Technical Specification 3.23.C.

2.0 Safety Consequences and Implications The charging pump SW subsystem (EIIS-BI) provides cooling water for the charging pump component cooling water subsystem (used for mechanical seal cooling) and the charging pump lubricating oil system. Normal operation of the charging pump service water system is with one SW pump operating and the other in standby on each unit. Charging pump lubricating oil and component cooling water temperatures remained within design limits during the event. The Unit 1 charging pump service water pump was returned to service within 11 minutes and no noticeable increase in charging pump temperatures was observed. Had the Unit 2 charging pump lube oil temperatures increased to an unaccept-able level, the pump would have been shut down.

Availability of a Unit 2 pump was required for charging cross-tie capability per T. S. 3.2.B.l. This specification has a seven day action statement.

The CR/RR air conditioning system consists of three air conditioning chiller units. During the short time the chillers were not operating, the CR/RR air handling units remained operating and there was no noticeable increase in ambient temperature of the CR/RR areas.

Neither event caused design limits to be exceeded.

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

3.0 Cause The cause of the event has been attributed to air entering the SW lines that supply the charging pump SW pumps and CR/RR chiller SW pumps. The exact mechanism by which air was introduced into the system could not be determined. The most likely source was air trapped in the partially drained SW supply line to the BCHXs which entered the SW supply line to the MCR/RR chiller NRC Form 366A (6-891

NRC FORM 366A (6-89)

LICENSEE EVENT REPORT (LER) e U.S. NUCLEAR REGULATORY COMMISSION e 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 TEXT CONTINUATION AND REPORTS MANAGE~ENT 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 (1) DOCKET NUMBER (2) PAGE (3)

LER NUMBER (6)

Surry Power Station, Units 1 and 2 TEXT (If ,non, 8{)at:e i* n,quimd, u"" addffiofllJ! NRC Form 366A '*I (17)

SW pumps and the charging pump SW pumps when MOV-SW-201B was opened. In addition, extensive modifications requiring draining of the entire Unit 2 circulating and service water piping trapped significant amounts of air in the top of the piping when it was refilled. The trapped air could not be effectively vented and moves slowly due to low service water flow velocities. The opening of the valve may have momentarily increased flow sweeping air into the in-service flow path and to the subject pumps.

The air binding can also be explained by the specific status of plant systems at the time. Three CR/RR SW pumps were operating during the event along with two charging pump SW pumps. This created a slight subatmospheric pressure condition on the suction side of the CR/RR chiller pumps and the charging pump SW pump. The Unit 2 discharge tunnel had been dewatered and was open to the atmosphere. Given the arrangement of the charging pump and CR/RR SW pump system piping coupled with the conditions described.above, it is possible that air may have been entering the system from the Unit 2 discharge tunnel. Consequently, a perturbation on the system, such as the opening of the MOV, could have increased the introduction of air into the system to the point where air binding of the pumps occurred.

4.0 Immediate Corrective Action(s)

Maintenance testing of the BCHX supply MOV was suspended. The procedure for abnormal SW system conditions was initiated, and venting of the SW pumps was commenced to allow refilling of the lines.

Charging pump temperatures were monitored to verify lubrication oil and component cooling water temperatures remained within design limits.

5.0 Additional Corrective Action(s)

A Unit 1 and a Unit 2 charging pump SW pump were vented and returned to service at 1758 hours0.0203 days 0.488 hours 0.00291 weeks 6.68919e-4 months and 1837 hours0.0213 days 0.51 hours 0.00304 weeks 6.989785e-4 months , respectively.

NRC Form 366A 16-89)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB 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 THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME 11) DOCKET NUMBER 12) LER NUMBER 16) PAGE 131 Surry Power Station, Units 1 and 2 01s101010121810 819 -01311-0iO 01s oFOl6 TEXT (If more /J/)(Jce is requlmd, U5" edditiontJ! NRC Form 366A's) 1171 The "A" and "B" CR/RR chillers were returned to service at 1850 hours0.0214 days 0.514 hours 0.00306 weeks 7.03925e-4 months after verifying that their operating parameters were normal.

6.0 Action(s) Taken to Prevent Recurrence Presently, two s~x inch SW supply lines are used to supply the CR/RR and charging pump SW pumps. A design change is being implemented to replace the six inch lines with three eight inch lines. These lines are being provided with appropriate venting capabilities.

Operators have been cautioned not to run three CR/RR chiller SW pumps simultaneously. In addition, they have been cautioned to ensure that piping downstream of MOVs located in an area that could affect operation of the charging pump. and CR/RR chiller SW pumps be verified full of water prior to opening the MOV.

Additional high point vents have been installed on the charging pump service water subsystem. High point vents have also been installed on the Unit 2 BCHXs.

A procedure has been developed for periodic venting of certain service water components to ensure that the system remains full of water. The abnormal procedure for loss of charging pump SW is also being enhanced to provide specific instructions for restoration of CR/RR and charging pump service water.

Engineering is continuing their investigation of the system to determine if additional corrective actions

'will enhance system operation.

7.0 Similar Events LER 280-88-20 described the complete loss of the charging pump SW system due to air binding when a SW supply valve in the system was opened. A deficient temporary operating procedure was identified as the cause of this event.

LER 280-89-30 describes a similar event that occurred on July 18. The precautions taken for the July 23 event were implemented as a result of the July 18 event.

NRC Form 366A 16-89)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (6-89) APPROVED 0MB NO. 3150-0104 E_XPIRES: 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 IP-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'(1) DOCKET NUMBER (2) LE B I l EI l

SEQUENTI L

::::::::* REVISION VEAR ,:::::::::: NUM R :::::::::: UMBER

Surry Power Station,*Units 1 and 2 TEXT (If morr, &pace i* ,wquiml, ua *ddmotYI NRC Form 366A'a/ 117) 8.0 Manufacturer/Model Number(s)

N/A NRC Form 366A 16-89)

ML18153B865

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