05000293/LER-1997-009, :on 970417,RCIC Sys Became Inoperable.Caused by Gear Change in Motor Operator of RCIC Sys Flow Test Valve. RCIC Sys Procedures for Potential Rev Reviewed

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:on 970417,RCIC Sys Became Inoperable.Caused by Gear Change in Motor Operator of RCIC Sys Flow Test Valve. RCIC Sys Procedures for Potential Rev Reviewed
ML20141L025
Person / Time
Site: Pilgrim
Issue date: 05/19/1997
From: Ellis D
BOSTON EDISON CO.
To:
Shared Package
ML20141L019 List:
References
LER-97-009, LER-97-9, NUDOCS 9706020251
Download: ML20141L025 (7)
v • d • e


LER-1997-009, on 970417,RCIC Sys Became Inoperable.Caused by Gear Change in Motor Operator of RCIC Sys Flow Test Valve. RCIC Sys Procedures for Potential Rev Reviewed
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(iii)
10 CFR 50.73(a)(2)(v), Loss of Safety Function
2931997009R00 - NRC Website
v • d • e

text

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NRc Form 366 U.S. NUCLEAR REGULATORY Commission APPROVED BY OMB No. 3150-0104 (4-95) '

EXPlREs 04/30f;B LICENSEE EVENT REPORT (LER ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS l

INFORMATION COLLECTION REQUEST: 50 0 HRS. REPORTED

[

LESSONS LEARNED ARE INCORPORATED INTO THE l

(See reverse for nurnber of LICENSING PROCESS AND FED BACK TO INDUSTRY.

l digits / characters for eacn block)

FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH j

(T-6 F33).

U.S.

NUCLEAR REGULATORY COMMISSION, WASHINGTON. DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON. DC 20503.

FACILITY NAME (1)

DOCKET NUMBER (2)

PAGE(3)

PILGRIM NUCLEAR POWER STATION 05000-293 1 of 7 TITLE (4)

RCIC System inoperable Due to Turbine Overspeed Trip During Suiveillance EVENT DATE (5)

LER NUMBER (6?

REPORT DATE (7)

OTHER FACILITIES INVOLVED (8)

SEQUENTIAL NUMBER REVISION F ACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER MONTH DAY YEAR M

MMO FACluTY NAME 05 19 97 DOCKET NUMBER 04 17 97 97 009 00 N/A 05000 OPZRATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR:(Check one or more).11)

MODE (9)

N 20 2201 (b) 20 2203(a)(2)(v) 50 73(a)(2)(i) 50 73(a)(2)(viii)

POWER 22.2203(a)(1) 20 2203(a)(3)(i) 50 73(a)(2)(ii) 50 73(a)(2)(x)

LEVEL (10) 016 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50.73(a)(2)(iii) 73.71 I

3) 2203(a)(2)(ii) 20 2203(a)(4) 50 73(a)(2)(iv) oTHER 20 2203(a)(2)(iii) 50 36(c)(1)

X 50.73(a)(2)(v) (D)

Specify in Abstract below 20 2203(a)(2)(iv) 50 36(c)(2) 50 73(a)(2)(vn) or in NRC Form 336A LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER (include Area Code)

Douglas W. Ellis 508-830-8160 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBEDIN THIS REPORT (13)

REPORTABLE TO REPORTABLE TO

CAUSE

SYSTEM COMPONENT MANUFACTURER NPRDS

CAUSE

SYSTEM COMPONENT MANUFACTURER NPRDS SUPPLEMYNTAL REPORT EXPECTED (14)

EXPECTED MONTH DAY YEAR YEs X

No submission (if yes, complete EXPECTED SUBMISSION DATE)

DATE(15)

AISTRACT (Lhnit to 1400 spaces. i e.. approximately 15 single spaced typewntten hnes) (16)

On April 17,1997, at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />, the reactor core isolation cooling (RCIC) system became inoperable, and a 14 day Technical Specification 3.5.D.2 limiting condition for operation (LCO) was entered. The system became inoperable because of a mechanical overspeed trip of the RCIC turbine that occurred during a surveillance test of the RCIC system. The test was conducted during startup from the 1997 refueling outage.

l The cause was a gear change in the motor operator of the RCIC system flow test valve. The gear change was l

made during the refueling outage and affected the time used to position (open) the flow test valve before the RCIC turbine-pump is started for the test. Applicable RCIC system procedures were not identified as impacted by the gear change. Corrective action taken included a change in the surveillance procedure. The change l

increased the time, from approximately three seconds to approximately five seconds, used to position the flow l

test valve for the test. The RCIC system was tested with satisfactory results, and the LCO was terminated on April 18,1997. Corrective action planned includes reviewing RCIC system procedures for potential revision and including this report in the engineering support training program.

The event occurred during startup from the 1997 refueling outage. The reactor mode selector switch was in the RUN position, and reactor power was 16 percent. The reactor vessel pressure was approximately 955 psig with the reactor water temperature at the saturation temperature for the pressure. The event posed no threat to public health and 9fety.

9706020 N 770519 PDR ADOCs 05000293 S

PDR

NRC F'orm 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

SEQUENTIAL REVISION l

YEAR NUMBER NUMBER PILGRIM NUCLEAR POWER STATION oson293 97 009 00 2 of 7 TEXT (if more space is required, use additional copies of NRC Form 366A) (17)

BACKGROUND As part of startup activities at the end of the 1997 refueling outage, the reactor core isolation cooling (RCIC) l system was tested on April 15,1997. At the time of the test, the reactor pressure was approximately 130 psig i

-- less than the 150 psig pressure at which the system is required to be operable (Technical Specification 1

3.5.D.1). The test was performed in accordance with procedure 8.5.5.3, *RCIC Flow Rate Test at Less Than or Equal to 150 PSIG," section 8.2. The test was completed with satisfactory results at approximately 1950 hours0.0226 days <br />0.542 hours <br />0.00322 weeks <br />7.41975e-4 months <br />.

The high pressure coolant injection (HPCI) system was similarly tested in accordance with procedure 8.5.4.3, "High Pressure Coolant Injection Operability Demonstration and Flow." The test was completed with satisfactory results at approximately 1835 hours0.0212 days <br />0.51 hours <br />0.00303 weeks <br />6.982175e-4 months <br /> on April 15,1997.

EVENT DESCRIPTION

On April 17,1997, at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />, the RCIC system became inoperable, and a 14 day Tecnnical Specification 3.5.D.2 limiting condition for operation (LCO) was entered.

l The system became inoperable due to a mechanical overspeed trip of the RCIC turbine. The turbine trip l

occurred when the RCIC turbine steam supply valve was opened at step 14 of surveillance test 8.5.5.1 (rev. 40)

(, "RCIC Pump Tech Spec and IST (Quarterly) Test." Prior to step 14, valve MO-1301-53 was i

jogged opened in accordance with step 12 of the procedure The RCIC pump test valve (MO-1301-53) is located l

in the RCIC pump flow test line piping. The control switch for valve MO-1301-53 is spring loaded. After the l

control switch was moved to and held in the OPEN position for approximately 3 three seconds, the control l

switch was released. Subsequently, at step 14, the turbine steam supply valve MO-1301-61 was opened, and l

the overspeed trip occurred.

Initial utility licensed operator actions consisted of investigating the cause of the trip. Except for the overspeed trip linkage, the RCIC system was aligned to its normal configuration. Valve MO-1301-53 was closed via its control switch. The mechanical overspeed trip linkage of the turbine trip throttle valve was left in the tripped condition pending further investigation for the cause of the overspeed trip.

Problem Report 97.9287 was written to document the overspeed trip, a maintenance request (MR 19701258) was written for further investigation, and an LCO (A97-100) was written to track continued plant operation with the RCIC system inoperable. Attachment 7, "RCIC System Inoperable," of procedure 8.C.34 (rev.14),

" Operations Technical Specifications Requirements for Inoperable Systems / Components," was completed by 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br />. The NRC Operations Center was notified of the event at 1408 hours0.0163 days <br />0.391 hours <br />0.00233 weeks <br />5.35744e-4 months <br /> in accordance with 10 CFR 50.72.

The event occurred during startup from the 1997 refueling outage. The reactor mode selector switch was in the RUN position, and reactor power was 16 percent. The reactor vessel pressure was approximately 955 psig with.

the reactor water temperature at the saturation temperature for that pressure.

I a,

NRc Form SS6A U.S. NUCLEAR REGULATORY COMMISSION I

(4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION l

FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

SEoUENTIAL REVISION YEAR NUMBER NUMBER PILGRIM NUCLEAR POWER STATION 05% 4293 97 009 00 3 of 7 TEXT (if more space is required, use additional copies of NRC Form 366A) (17)

CAUSE

The direct cause of the RCIC system becoming inoperable at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br /> was the activation of the RCIC turbine mechanical overspeed trip device. The device is mounted on the turbine shaft. Upon activating, the device trips the mechanical linkage that is connected to the turbine trip throttle valve. The trip throttle valve (SV-1301-1) is located in the turbine steam supply piping downstream of the RCIC steam supply valve MO-1301-61 and upstream of the turbine steam governor valve HO-1301-159. The overspeed trip setting (5512 to 5737 rpm) of ths overspeed device is approximately 125 percent +/- 2 percent of the rated turbine speed (4500 rpm).

As part of the cause investigation, the RCIC turbine-pump was manually started in accordance with procedure 8.5.5.11 (rev. 0), " Manual Start of the RCIC Turbine for Maintenance Activities," at 1659 hours0.0192 days <br />0.461 hours <br />0.00274 weeks <br />6.312495e-4 months <br />. The procedure was conducted to verify the turbine controls were operating properly. The test includes jogging valve MO-1301-53 open for approximately three seconds at step 10 and opening the turbine stearn supply valve MO-1301-61 at step 11. The jogging open of valve MO-1301-53 for approximately three seconds was based on previous experience and is necessary to establish the RCIC turbine-pump parameters near to the system test parameters. After opening valve MO-1301-61 at step 11, the turbine started and was brought to normal operating parameters in accordance with the subsequent steps in the procedure using the handwheel of the turbine trip throttle valve. The turbine controls, including the RCIC flow controller FIC-1340-1, were tested in the manual and automatic control modes with satisfactory results.

Continued investigation identified a gear change made to valve MO-1301-53 during the 1997 refueling outage.

l The change was made in accordance with a design change (PDC 96-108) that was part of upgrades made to motor operated valves (Generic Letter 89-10). The gear change was implemer.ted by a maintenance document (P9500704) and changed the overall gear ratio of MO-1301-53 by approximately 60 percent. The change J

cffectively increased the time needed forjogging open MO-1301-53 to the desired position necessary to establish the RCIC turbine-pump parameters near to system test parameters for the surveillance test. The applicable RCIC system procedures, including procedure 8.5.5.1 were not identified as impacted by the design l

modification (gear change) made to valve MO-1301-53. As a result of not increasing the time for jogging open MO-1301-53, less flow was able to pass through the RCIC flow test line. When the turbine steam supply valve was opened for the surveillance test at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />, the turbine started and accelerated as expected.

Maanwhile, the RCIC fiaw controller, receiving flow signals that were less than normal due to less flow through valve MO-1301-53, mr.intained the turbine governor valve (HO-1301-159) in the full open position to achieve the dssired turbine speed / pump flow. The governor valve, however, should quickly throttle (close) to control the turbine's acceleration or an overspeed condition will occur. The govemor valve did not throttle because the test flow was less than the flow demanded by the flow controller. The test flow was less than the flow demand (400 l

gpm) because of the noted effect of the gear change made to MO-1301-53, and the turbine's mechanical overspeed device functioned to trip the turbine's trip throttle valve linkage and result in the event. Therefore, the l

root cause of the overspeed trip that occurred at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br /> was the applicable RCIC system procedures, including procedure 8.5.5.1, were not identified as impacted by the design modification (gear change) made to valve MO-1301-53 during the 1997 refueling outage, i

l I4

_ _ _ ~ _ _

NRC Fo'rm 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

SEQUENTIAL Revision YEAR NUMBER NUMBER PILGRIM NUCLEAR POWER STATION 05N293 97 009 00 4 of 7 TEXT (if more space is reqwred. use additional copes of NRc Form 366A) (17)

Procedure 8.5.5.1 was changed (via SRO 97-135) to increase the opening time for valve MO-1301-53 from j

approximately three seconds to approximately five seconds. After the change to procedure 8.5.5.1, the RCIC system was started automatically in accordance with procedure 8.5.5.1 Attachment 1 at 1755 hours0.0203 days <br />0.488 hours <br />0.0029 weeks <br />6.677775e-4 months <br />. Valve MO-1301-53 was jogged open, this time for approximately five seconds (SRO 97-135) at step 12, the turbine steam supply valve MO-1301-61 was opened at step 14, and the turbine-pump started. As part of step 15, operator actions are to verify or adjust the flow controller (FIC-1340-1) and adjust the position of valve MO-1301-53. Per step 15, the manipulation of MO-1301-53 may be accomplished either locally at the valve by using the valve's handwheel or remotely from the control room by using the valve's control switch. Valve MO-l 1301-53 was momentarily jogged in a closed direction via its control switch to adjust the turbine speed / pump t

flow. The valve, however, continued to fully close automatically, and a turbine overspeed trip occurred at 1755 J

hours.

The investigation for the overspeed trip at 1755 hours0.0203 days <br />0.488 hours <br />0.0029 weeks <br />6.677775e-4 months <br /> revealed that valve MO-1301-53 fully closed instead of throttling in the closed direction as expected. The valve was stroked and the valve's control circuitry functioned as a seal-in type circuit in the closed direction. Problem Report 97.9290 was written to document that the closing portion of the control circuit of valve MO-1301-53 was found to be functioning as a seal-in type circuit instead of a jog type circuit. The closing of the valve resulted in a flow decrease and shortly, no flow through the flow test line. The effect of no flow caused the turbine governor valve to fully open, and the turbine speed increased until the overspeed trip occurred at 1755 hours0.0203 days <br />0.488 hours <br />0.0029 weeks <br />6.677775e-4 months <br />. The investigation included an inspection of the former cubicle / breaker D781 that powered valve MO-1301-53. The inspection revealed wiring that had been relanded at auxiliary relay RCR. The relanding had changed the control switch circuit from a seal-in to a jog circuit in the close direction; this wiring change was not documented on wiring diagram E9-9-6 and RCIC elementary drawings M1G11-11 and M1G27 that showed the circuit to be a sealin circuit. A design modification (PDC 93-38) was issued in July 1994 for the replacement of 125 vde and 250, vdc cubicles, including cubicle i

D781. Cubicle D781 was replaced during the 1997 refueling outage (RFO-11). The new cubicle was wired in accordance with a new wiring diagram E9A-8 that was based on wiring diagram E9-9-6. After the replacement of cubicle D781, the control switch circuit functioned as a seal-in type circuit in the close direction in accordance with design drawing E9A-8 (PDC 93-38) because the previous (undocumented) wiring change was not documented on drawing E9-9-6. The time frame of the undocumented wiring change could not be determined.

Review of past drawing revisions and historical maintenance request (s) for cubicle D781 revealed no i

documented changes for the circuit. The undocumented change could have been made during initial RCIC system testing conducted as part of plant startup testing (c.1972) or during some subsequent activity prior to the 1997 refueling outage.

The noted problems with the opening time of MO-1301-53 and the valve's co-trol circuitry were not detected curing the performance of procedure 8.5.5.3 on April 15,1997, because the test was performed when the steam, pressure was approximately 130 psig. At 130 psig steam pressure, there is not as much energy in the i

steam, and therefore, the RCIC turbine governor valve remains at or near the full open position during testing (approximately 130 psig). Valve MO-1301-53 was jogged open for approximately three seconds at procedure section 8.2 ster [7] and was adjusted (jogged further open) at section 8.2 step (13). Review of plant information computer (EPIC) data indicates valve MO-1301-53 was jogged open to meet test criteria and was not jogged closed.

The noted problem with the control switch closing circuit of valve MO-1301-53 was not detected during the i

performance procedures 8.5.5.1 (April 17,1997, at 1315 hours0.0152 days <br />0.365 hours <br />0.00217 weeks <br />5.003575e-4 months <br />) and 8.5.5.11 (April 17,1997, at 1659 hours0.0192 days <br />0.461 hours <br />0.00274 weeks <br />6.312495e-4 months <br />) while at 955 steam pressure because valve MO-1301-53 was not jogged in the closed direction during the tests.

Prior to RFO-11, the control switch for valve MO-1301-53 functioned as a jog circuit, not a seal-in circuit.

l!

HRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (4-9s)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FAClu rY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

SEQUENTIAL REVistoN YEAR NUMBER NUMBER PILGRIM NUCLEAR POWER STATION o m 293 97 009 00 5 of 7 TEXT (If more space is required, use addihonal copies of NRc Form 366A) (17)

The replacement of cubiclo D781 effectively changed the function to that of a seal-in circuit in the close direction. The effect of this change was not known to the operators who performed the noted tests on A.pril 15,1997, and April 17,1997. Valve MO-1301-53 was jogged in the open direction, not the close direction, at the beginning of the tests. The va;ve was adjusted (jogged in the open direction), not jogged in the close dircction during the tests. The valve was closed at the completion of the tests by the operators' use of the control switch, held in the close direction, until the valve was fully closed in accordance with previous experience (valve MO-1301-53 functioning as a jog valve in the open and close position). To the operators, the full closing of the valve while holding the control switch in the close direction was consistent with past experience, but they were unaware the control switch circuit in the close direction was functioning as a seal-in circuit. Therefore, the root cause of the turbine overspeed trip that occurred at 1755 hours0.0203 days <br />0.488 hours <br />0.0029 weeks <br />6.677775e-4 months <br /> on April 17,1997, was the wiring change in the former cubicle (D781) that was not documented on wiring diagram E9-9-6 and RCIC system elementary drawings M1G11-11 and M1G27.

Neither the valve MO-1301-53 gear change nor the undocumented wiring change resulted in a failure of valve MO-1301-53. The automatic closing circuit for valve MO-1301-53 is wired in parallel with the valve's controf switch and was not affected by the seal-in circuit wiring. Valve MO-1301-53 is designed to close automatically if a low reactor water level condition occurs or either of the two normally-closed, in-series RCIC pump suction l

valves (MO-1301-25 and -26) from the suppression pool are fully open. The RCIC system is designed to automatically start if a low reactor water level condition occurs.

CORRECTIVE ACTION

Corrective action taken included the following:

Procedure 8.5.5.1 (rev. 40) was changed on April 17,1997. Specifically, the change (SRO 97-135) was o

l made to Attachment 1 step 12 and step 9 of Attachment 2, "RCIC System Checkout Test." These changes pertain to the time forjogging open valve MO-1301-53. The time forjogging open valve MO-1301-53 was changed from approximately three seconds to approximately five seconds.

l An engineering design change (FRN 93-38-21) was issued on April 18,1997. The document changed the e

l closing circuit from a seal-in type circuit to a jog type circuit. The affected drawings will be revised as part of l

the routine modification close-out process. With this change, the control circuitry for MO-1301-53 functions i

as a jog circuit in the open and close directions. The change did not affect the automatic closing function of valve MO-1301-53.

, After FRN 93-38-21 was implemented, valve MO-1301-53 was strokeri dogged in the open and close directions)

I with satisfactory results at 0731 hours0.00846 days <br />0.203 hours <br />0.00121 weeks <br />2.781455e-4 months <br /> on April 18,1997. The RCIC system was subsequently tested in accordance with procedure 8.5.5.1 (rev. 40 with SRO 97-135) Attachment 1. The test was completed with satisfactory results, and the LCO (A97-100) was terminated at 1723 hours0.0199 days <br />0.479 hours <br />0.00285 weeks <br />6.556015e-4 months <br /> on April 18,1997.

_ ~ -.~ -. - - -.

c

, NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

SEQUENTIAL REVisloN YEAR NUMBER NUMBER PILGRIM NUCLEAR POWER STATION N 293 97 009 00 6 of 7 TEXT (If more space is required, use additional copies of NRc F.sm 366A) (17)

A review was conducted of the other cubicles replaced via PDC 93-38. The review focused on cubicles that powsr motor-operated valves that contain a jog control switch circuit. The review included operations d:partment personnel involvement regarding the respective valve's operational function (jog versus seal-in).

The review concluded the cubicles are wired in accordance with design, and the undocumented wiring change was an isolated instance that could date back to initial startup testing (c.1972). Current procedures and work practices require approved design changes for wiring changes, and documenting wiring discrepancies in accordance with the problem report process.

Corrective action planned includes the following:

RCIC system procedures including 2.2.22 (currently rev. 47B), " Reactor Core Isolation Cooling System,"

e 8.5.5.3 (currently rev. 26) and 8.5.5.11 (currently rev. 0) will be reviewed. The focus of the review is for potential revision to change the time for jogging valve MO-1301-53 open from approximately three seconds to approximately five seconds.

t RCIC system procedures including procedures 8.5.5.3 and 8.5.5.11 will be reviewed. The focus of the e

review is for potential revision to identify the methods of manipulating the position of valve MO-1301-53 similar to the methods (local handwneel or remotely via the control switch) contained in procedure 8.5.5.1.

Corrective action for the failure to identify the impact of the gear change (design modification) to the motor e

operator of MO-1301-53 relative to the RCIC procedures is to include this report in the engineering support training program.

SAFETY CONSEQUENCES

l This event posed no threat to public health and safety.

The HPCI system was operable during the period the RCIC system was inoperable.

This report was submitted in accordance with 10 CFR 50.73(a)(2)(v)(D) because the RCIC system became inoperable.

SIMILARITY TO PREVIOUS EVENTS A review for similarity was conducted of Pilgrim Station LERs submitted since January 1984. The review was focused to LERs involving an overspeed trip of the RCIC turbine. The review identified a previous instance of a RCIC turbine overspeed trip that was reported in LER 91-025-00.

1 1l

-. = - -

,' NRc Form 366A U.S. NUCLEAR REGULATORV COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

SEQUENTIAL REv:SloN YEAR NUMBER NUMBER PILGRIM NUCLEAR POWER STATION 050 %-293 97 009 00 7 of 7 TEXT (if more space is required, use additional copies of NRc Form 366A)(17)

For LER 91-025-00, a RCIC turbine mechanical overspeed trip occurred on October 30,1991. The trip occurred when the RCIC system was being started for reactor water level control (injection mode) following a loss of off-site power event. The system was started in accordance with step 5 of Attachment 8 of procedure 2.2.22, "Raactor Core Isolation Cooling System." For the step, the RCIC turbine steam supply valve (MO-1301-61) is

)

opened first with the injection valve opened when the turbine speed increases. The steam inlet valve was l

opened, and the overspes. trip occurred approximately four seconds before the injection valve was opened.

l Corrective action taken included the revision of procedure 2.2.22 to provide instructions on the opening of the injsetion valve at the s.we time the turbine steam supply valve is opened, and a design modification. The modification (PDC 92-55) iv.talled a single push button on control room panel C904 for starting the RCIC l

system in the injection mode.

l l

ENERGY INDUSTRY IDENTIFICATION SYSTEM (Ells) CODES The Ells codes for this report are as follows:

COMPONENTS CODES Breaker (D781)

BKR Device, overspeed 12 Valve (SV-1301-1)

V Valve, test (MO-1301-53)

TV SYSTEMS High pressure core isolation cooling system BJ Reactor core isolation cooling system BN l

l l

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