ML20005D742

LER 89-033-00:on 891106,automatic Actuation of Group 1 Portion of Primary Containment Isolation Control Sys (PCIS) Occurred.Caused by High Reactor Vessel Water Level.Manual Valve Closed & PCIS Logic Circuitry reset.W/891206 Ltr

ML20005D742
Person / Time
Site:	Pilgrim
Issue date:	12/06/1989
From:	Bird R, Ellis D BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BECO-89-172, LER-89-033, LER-89-33, NUDOCS 8912140406
Download: ML20005D742 (6)

Text

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Ry 10 CFR 50.73 V s. .

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BO$1DNED6CN Pilgrim Nuclear Power station

.. Rocky Hill Road Plymouth, Massachusetts 02360 Ralph G. Bird

, senior Vice President - Nuclear December 6, 1989

c BECo Ltr. 89 172 U.S. Nuclear Regulatory Commission

-Attn: Document Control Desk Hashington 0.C. 20555 Docket No. 50-293 License No. DPR-35

Dear Sir:

The enclosed Licensee Event Report (LER) 89-033-00, " Automatic Closing of the Group 1 (one) Isolation Valves due to High Reactor Vessel Water Level During Startup", is submitted in accordance with 10 CFR Part 50.73.

Please do not hesitate to cor. tact me if there are any questions regarding this report.

G B DHE/bal

Enclosure:

LER 89-033-00 cc: Mr. Hilliam Russell Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Rd.

King of Prussia, PA 19406 Sr. NRC Resident Inspector - Pilgrim Station Standard BECo LER Distribution 8912140406 891106 7'62 L

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F ACILITY NAME 111 PDCKET NUMBER Q) PAGE G Pilgrim Nuclear Power Station 1 loFl 0 f r; 0 l5 l 010 l 0121913

"' Automatic Closing of the Group 1 (one) Isolation Valves due to liigh Reactor Vessel l Water Level During Startup EVENT DATE ($1 LER TUMBER 461 REPORT DATE (7) OTHER F ActLITl!5 INVOLVED 48) ,

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NAME TELEPHONE NUMBER ARE A CODE Douglas W. Ellis - Senior Compliance Engineer 5 1018 7141 71-I8 11 1610 COMPL ETE ONE LINE FOR E ACH COMPONENT F AILURE DESCRIBED IN THIS REPORT H31 j M ' C' "I'0RTA LE MA RE TA E ,

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l On November 6,1989 at 1539 hours0.0178 days <br />0.428 hours <br />0.00254 weeks <br />5.855895e-4 months <br />, an automatic actuation of the Group 1 (one)

I portion of the Primary Containment Isolation Control System (PCIS) occurred during l the initial stage of a startup. The actuation resulted in the automatic closing of the related Primary Containment System isolation valves that were in the open position.

L l The direct cause for the actuation was high Reactor Vessel (RV) water level. The I high RV water level (+50 inches narrow range level) occurred because a six inch manually operated valve, located in-parallel with the Feedwater System startup regulating valve, was in the incorrect (open) position at the time of the startup.

Corrective action taken included closing the manual valve, restoring the RV water l

1evel to normal, resetting the PCIS logic circuitry, and a walkdown of applicable systems that revealed no other mispositioned valves. Corrective actions planned include improving verbal communications and relabeling the identification tags for remote reach rods to include the identification number of the valve connected to the reach rod.

This event occurred during the startup mode with the reactor mode selector switch in the STARTUP position. The reactor power level was approximately one percent.

The RV pressure was approximately three psig with the RV water temperature at 220 degrees Fahrenheit. This report is submitted in accordance with 10 CFR 50.73(a)(2)(iv) and this event posed no threat to the public health and safety.

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0 l0 01 2 oF 0 15 nxis .,.-r. mc w me.mn EVENT DESCRIPTION 4 On November 6, 1989 at 1539 hours0.0178 days <br />0.428 hours <br />0.00254 weeks <br />5.855895e-4 months <br />, an automatic actuation of the Main Steam  ;

System / Group 1 (one) portion of the Primary Containment Isolation Control System i (PCIS) occurred due to a high Reactor Vessel (RV) water level. j The actuation resulted in the following designed responses. The inboard and j

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outboard Primary Containment System (PCS)/ Main Steam Isolation Valves (MSIVs), in the open position, closed automatically. The inboard and outboard PCS/ Main Steam drain valves (M0-220-1 and -2), in the open position, closed automatically. The.

inboard and outboard PCS/ Sample System valves (AO-220-44 and -45), in the open position, closed automatically, j The high RV water level occurred during the initial stage of the startup while at step 36 of Attachment 1 (OPER-01, "Startup Checklist") of procedure 2.1.1 (Rev. 59), "Startup from Shutdown". At that point in the startup, a Feedwater System Train 'A' block valve (M0-3477) was opened in order to provide condensate to the feedwater startup regulating valve (FV-643). The control switch for the block valve (M0-3477) is a seal-in type, i.e. the valve opens fully (60 seconds) upon demand. After the control switch was moved to the OPEN position, and as the valve M0-3477 was opening, the RV water level began to increase even though the startup regulating valve (FV-643) was in the closed position. [After the event the manually operated valve HO-443, located in-parallel with valve FV-643, was found to be in the (incorrect) open position.] Meanwhile, the control switch for valve -

M0-3477 was moved to the CLOSE position when the valve reached the fully open position. However, the Condensate System pump that was in service provided a flowrate through valve M0-3477 (being closed but with a 60 second closing time) and six inch valve H0-443, that was sufficient to result in the high RV water level.

The high RV water level resulted in the PCIS actuation before valve M0-3477 attained the fully closed position.

The RV water level was restored to normal (i.e., +30 inches narrow range level) by the letdown of water to the Main Condenser via the Reactor Water Cleanup System.

The PCIS logic circuitry was reset on November 6,1989 at 1635 hours0.0189 days <br />0.454 hours <br />0.0027 weeks <br />6.221175e-4 months <br /> and the affected valves were reopened.

Failure and Malfunction Report 89-428 was written to document the actuation. The NRC Operations Center was notified in accordance with 10 CFR 50.72 on November 6, 1989 at 1825 hours0.0211 days <br />0.507 hours <br />0.00302 weeks <br />6.944125e-4 months <br />.

This event occurred during the startup mode with the reactor mode selector switch in the STARTUP position. The control rods were in a partially withdrawn position with the reactor power level at approximately 1 (one) percent. The RV pressure was approximately 3 (three) psig with the RV water temperature at 220 degrees Fahrenheit. One of the three Condensate System pumps was in service. The Feedwater System pumps were not in service. The Feedwater System Train 'A' and Train 'B' regulating valves (FV-642A and FV-642B) and startup regulating valve (FV-643) were in the closed position and not in service.

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The direct cause for the actuation was a high RV water level condition. The maximum RV water level that occurred was approximately +50 inches (narrow range level).

The cause for the high RV water level was the mistaken opening of valve H0-443 instead of a feedwater startup manual block valve (H0-444B) while shutdown for '

scheduled maintenance and testing. Contributing causes were verbal miscommunication and less than adequate information provided on identification tags for manual valve remote operators (i.e., reach rods).

'The feedwater startup manual block valves (H0-444A and H0-4448) are normally open and are remotely operated via reach rods (S-6-8 for H0-444A and S-6-9 for H0-4448). Valve HO-443 is normally closed and is also remotely operated via a reach rod (S-6-5). The label for each reach rod identifies the reach rod number (e.g., S-6-9) and functional description but does not specifically identify the '

valve (e.g., H0-444B) connected to the reach rod. During the outage, work was performed on the Feedwater System regulating valves (FV-642A and FV-6428) and the startup regulating valve (FV-643). After the work, the manual block valves (H0-444A and H0-444B) were to be opened. However, because of verbal

.miscommunication and less than adequate information (i.e., valve number not identified) on the identification tags for the reach rods, the feedwater startup bypass valve (H0-443) was opened instead of a feedwater startup block valve (H0-444B) when the block valves (H0-444A and H0-4448) were to be opened.

CORRECTIVE ACTION The-following corrective actions have been taken:

• The valve H0-443 was closed.

• The valve lineups for systems wd on during the outage were checked with satisfactory results. The ' m.up checks consisted of field inspection of specified valves in the Feedwater, High Pressure Coolant l

Injection, Reactor Core Isolation Cc'oling, Core Spray, and Residual Heat Removal Systems. The inspections revealed no other mispositioned valves.

Corrective actions planned include the following:

• Station Instruction SI-0P.006 (Rev.1), " Operations Communications", will

! be revised. The focus of the revision is to improve the specificity of l verbal instructions.

• The labeling of remote reach rods will be improved to include the identification of the valve on the reach rod identification label. The l

labeling is administratively controlled via procedure 1.3.79, " Operations Equipment Labeling".

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T1xt - 4.w mac-2.a4m SAFETY CONSEOUENCES This event posed no threat to the public health and safety.

The actuation was the designed response to the high RV water level. The water level that occurred, i.e. +50 inches narrow range level, was slightly above the high RV water level setpoint (calibrated at approximately +45 inches). The bottom of the 20 inch Main Steam System piping corresponds to a level approximately 112 inches above zero inches narrow range level. Therefore, the maximum RV water level that occurred (i.e., +50 inches) was approximately 62' inches below the Main Steam System piping.

This report is submitted in accordance with 10 CFR 50.73(a)(2)(iv) because the Group 1 (one) portion of the PCIS logic circuitry was actuated.

SIMILARITY TO PREVIOUS EVENTS A review was conducted of Pilgrim Station Licensee Event Reports (LERs) submitted since January 1984. The review focused on LERs submitted in accordance with 10 CFR 50.73(a)(2)(iv) that involved a high RV water level. The review identified high RV water level events that were reported in LERs 50-293/84-020-00, 85-014-00, 88-024-00, 89-007-00, and 89-015-00.

For LER 84-020-00, a PCIS Group 1 (one) isolation signal occurred due to a high RV water level on December 25, 1984 at 1905 hours0.022 days <br />0.529 hours <br />0.00315 weeks <br />7.248525e-4 months <br />. The isolation signal resulted in the automatic closing of the MSIVs. At the time of the event, the reactor power level was approximately one percent, the reactor mode selector switch (RMSS) was in the STARTUP position, the RV pressure was approximately 100 psig, the RV water level was being manually controlled, and the Residual Heat Removal System (RHRS) was in the Suppression Pool Cooling (SPC) mode of operation. The cause for the high water level was attributed to leakage of RHRS/SPC water past the seat of an RHRS valve (MO-1001-28A) and into the RV.

l For LER 85-014-00, a PCIS Group 1 (one) isolation signal and a Reactor Protection System (RPS) scram signal and reactor scram at 10 percent reactor power occurred due to a high RV water level on June 15, 1985 at 0435 hours0.00503 days <br />0.121 hours <br />7.19246e-4 weeks <br />1.655175e-4 months <br />. The isolation signal l resulted in the autoniatic closing of the MSIVs. At the time of the event, the RMSS i

was in the STARTUP position, the RV pressure was approximately 700 psig, and the RV water level was being manually controlled. The cause for the high water level was attributed to utility licensed operator error. The scram signal occurred because L

the RV pressure was approximately 700 psig when the HSIVs closed. A high water I level in the RV (i.e., closing of the MSIVs) results in a scram signal when the

• RMSS is in the REFUEL or SHUTDOWN or STARTUP position, and if the RV pressure is i

1 greater than approximately 600 psig.

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TEXT f# moso eseco de mounoc( ese edweener 44C Form JW W 11h For LER 88-024-00, a PCIS Group 1 (one) isolation signal occurred due to a high RV water level on October 17, 1988 at 1433 hours0.0166 days <br />0.398 hours <br />0.00237 weeks <br />5.452565e-4 months <br />. The isolation signal resulted in the automatic closing of the MSIVs. At the time of the event, the reactor power level was zero percent, the RMSS was in the REFUEL position for a surveillance activity, the RV pressure was zero psig, and the RV water level was being manually controlled. The cause for the high water level was attributed to a pin that became disassociated from the feedback cam linkage of the positioner for the Feedwater System Train 'A' regulating valve (FV-642A).

For LER 89-007-00, a PCIS Group 1 (one) isolation signal occurred due to a high RV water level on February 4,1989 at 0936 hours0.0108 days <br />0.26 hours <br />0.00155 weeks <br />3.56148e-4 months <br />. The isolation signal resulted in the automatic closing of the inboard MSIVs. The outboard steam line 'C' MSIV closed automatically and the other outboard MSIVs remained closed. At the time of the event, the reactor power level was approximately 0.8 percent, the RMSS in the STARTUP position, and the RV pressure was approximately 278 psig. The MSIVs were being tested with a differential pressure of approximately 150 psid across the seat of the MSIV(s). The high water level was caused by the swell (expansion) of RV water that occurred when the outboard line 'C' MSIV was opened for testing. The cause for the event was attributed to an inadequacy in the development and review of the approved test procedure and a relatively fast opening time for the MSIV.

For LER 89-015-00, a high RV water level on May 3, 1989 at 0326 hours0.00377 days <br />0.0906 hours <br />5.390212e-4 weeks <br />1.24043e-4 months <br /> resulted in an automatic sequence of designed responses that included a Turbine-Generator Trip, a PCIS Group 1 (one) isolation signal, and an RPS scram signal ar.d reactor scram at 24 percent reactor power. At the time of the event, the RMSS was in the RUN position and the RV pressure was approximately 940 psig. The high water level occurred while troubleshooting the actuator controls for the Feedwater System Train

'B' regulating valve (FV-642B). The primary cause for the high water level was attributed to the use of a general troubleshooting procedure (3.M.3-8) for troubleshooting the actuator controls of the feedwater regulating valve (FV-6428).

ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) C00f3

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The EIIS codes for this report are as follows:

l COMPONENTS CQQES Valve, Isolation ISV Valve, Control, Flow FCV SYSTEMS Condensate System SD Containment Isolation Control System (PCIS) JM Engineered Safety Features Actuation System (PCIS) JE Feedwater System SJ

! Main Steam System SB 1

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