ML17290A488

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LER 93-022-00:on 930524 & 25,control Rods Withdrawn W/Scram Accumulators Inoperable.Caused by Plant Procedures Failing to Provide Guidance to Assure Inoperable Control Rods Disarmed.Procedures Will Be revised.W/930625 Ltr
ML17290A488
Person / Time
Site: Columbia Energy Northwest icon.png
Issue date: 06/25/1993
From: Mackaman C, Parrish J
WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-93-168, LER-93-022, LER-93-22, NUDOCS 9306300224
Download: ML17290A488 (7)
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Text

ACCEI E 'CED DOCVMENT DISTmUSUTION SYSTEM REGU RY INFORMATION DISTRIBUTOI SYSTEM (RIDE)

ACCESSION NBR:9306300224 DOC.DATE: 93/06/25 NOTARIZED: NO DOCKET FACIL:59-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION MACKAMAN,C.D. Washington Public Power Supply System PARRISH,J.V. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 93-022-00:on 930524 a 25,control rods withdrawn w/scram accumulators inoperable. Caused by plant procedures failing to provide guidance to assure inoperable control rods disarmed. Procedures will be revised.W/930625 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES: ,A I

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL D PDV LA 1 1 PDV PD 1 1 CLIFFORDFJ 1 . 1 D INTERNAL: ACNW 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 1 NRR/DORS/OEAB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRIL/RPEB ' 1 NRR/DRSS/PRPB 2 2 NRR/DSS~A SPLB 1 1 NRR/DSSA/SRXB 1 1* REG Z,W~ 02 1 1 RES/DSIR/EIB 1 1 RGN5 FILE 01 1 1 EXTERNAL: EG6G BRYCE,J.H 2 2 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1 1 D

D D

NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTEI CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 32 ENCL 32

WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.o. Box 96B ~ 3000 George Washington Way ~ Richland, Washington 99352 June 25, 1993 G02-93-168 Docket No. 50-397 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

NUCLEAR PLANT WNP-2, OPERATING LICENSE NPF-21 LICENSEE EVENT REPORT NO.93-022 Transmitted herewith is Licensee Event Report No.93-022 for the WNP-2 Plant. This report is submitted in response to the report requirements of 10CFR50.73 and discusses the items of reportability, corrective action taken, and action taken to preclude recurrence.

Sincerely, J. V. Parrish (Mail Drop 1023)

Assistant Managing Director, Operations JVP/CDM/cgeh Enclosure CC: Mr. B. H. Faulkenberry, NRC - Region V Mr. R. Barr, NRC Resident Inspector (Mail Drop 901A, 2 Copies)

INPO Records Center - Atlanta, GA Mr. D. L. Williams, BPA (Mail Drop 399)

<. gC 0P l-", "

9306300224 930625 PDR ADOCK 05000397 8 PDR

LICENSEE IONT REPORT (LER)

FACILITY HAME (1) DOCKET NUHB R ( ) PAGE (3)

Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 I OF ITLE (4)

TWO CONTROL RODS WERE WITHDRAWNWITH THEIR SCRAM ACCUMULATORS INOPERABLE EVENT DATE 5 LER NUHBER ( 6) REPORT DATE (7 OTHER FACILITIES INVOLVED 8 HONTH DAY YEAR YEAR SEQUENTIAL EV I SION MONTH OAY YEAR FACILITY NAHES CKE UMB R (5)

NUMBER UHBER 50 0 5 2 4 9 3 9 3 0 2 2 0 0 0 6 2 5 9 3 50 PERATING HIS REPORT IS SUBHITTEO PURSUANT TO THE REQUIREHENTS OF 10 CFR E: (Check one or more of the following) (ll)

ODE (9) 5 ONER LEVEL 20.402(b) 20.405(C) 0.73(a)(2)(iv) 77.71(b)

(10) 20.405(a)(1)(i) 50.36(c)(1) 50.73(a)(2)(v) 73.73(c) 20.405(a)(1)(ii) 50.36(c)(2) 50.73(a)(2)(vii) THER (Specify in Abstract 20.405(a)(1)(iii) 50.73(a)(2)(i) 0.73(a)(2)(viii)(A) elow and in Text, NRC 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Form 366A) 20.405(a)(1)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER 12)

NAME TELEPHOHE NUMBER C. D. Mackaman, Licensing Engineer REA CODE 5 0 9 7 7 - 4 4 5 1 COHPLETE OHE LINE FOR EACH COHPOHEHT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPOHEHT HANUFACTURER EPORTABLE CAUSE SYSTEH COHPOHEHT HAHUFACTURER EPORTABLE 0 HPRDS TO HPRDS SUPPLEHEHTAL REPORT EXPECTED (14) EXPECTED SUSHI SSI ON HOHTH DAY YEAR ATE (15)

YES (If yes, complete EXPECTED SUBMISSIOH DATE) HO On May 26, 1993, two control rod withdrawal events were identified as having violated Technical Specifications. Previously, on May 24 and 25, 1993, during the annual Maintenance and Refueling Outage, Control Rods "10-11" and "26-35," respectively, were withdrawn with their scram accumulators inoperable. The scram accumulators were inoperable because their associated level switches had failed Surveillance Procedure PPM 7.4.1.3.5.2, "Scram Accumulator Pressure Detection CC/Level Detection-CFT/CC." Withdrawing a control rod with its scram accumulator inoperable is contrary to WNP-2 Technical Specification 3.1.3.5.

Immediate corrective action by Plant Operators was to disarm Hydraulic Control Units (HCUs) "10-11" and "26-35" hydraulically.

The root causes of this event were: (1) Plant procedures did not provide guidance to assure that inoperable control rods were disarmed, and (2) faulty scram accumulator level switches were not repaired in a timely manner. Further corrective actions will revise applicable procedures to provide direction to disarm an inoperable control rod and repair a faulty scram accumulator level switch on a high priority basis.

This event posed no threat to the health and safety of either the public or plant personnel.

LICENSEE EVENT REP(4 (LER)

TEXT CONTINUATION AGILITY NAHE (1 j DOCKET NUHBER (2) LER NUHBER (B) AGE (3) ear umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 2 2 0 2 F 5 ITLE (4)

TWO CONTROL RODS WERE WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE Plan ndition Power Level - 0%

Plant Mode - 5 (Refueling)

Even Descri i n On May 26, 1993, two control rod withdrawal events were identified as having violated Technical Specifications. Previously, on May 24 and 25, 1993, during the annual Maintenance and Refueling Outage, Control Rods "10-11" and "26-35," respectively, were withdrawn with their scram accumulators inoperable. The scram accumulators were inoperable because their associated level switches had failed Surveillance Procedure PPM 7.4.1.3.5.2, "Scram Accumulator Pressure Detection CC/Level Detection-CFT/CC." Withdrawing a control rod with its scram accumulator inoperable is contrary to WNP-2 Technical Specification 3.1.3.5.

The Hydraulic Control Units (HCUs) for Control Rods "26-35" and "10-11" were declared inoperable on May 16 and 18, 1993, respectively, for faulty scram accumulator level switches found during PPM 7.4.1.3.5.2. The HCUs were declared inoperable because the scram accumulators and level switches are HCU components required for unit operability. The level switches provide a trouble alarm and Full Core Display trouble indication of scram accumulator water leakage. The inoperable HCUs were listed in the Control Room Inoperable Equipment Log and Maintenance Work Requests (MWRs) were written for both failed scram accumulator level switches.

On May 24, 1993, at 0244 hours0.00282 days <br />0.0678 hours <br />4.034392e-4 weeks <br />9.2842e-5 months <br />, control rod timing testing commenced in accordance with Nuclear Performance Procedure PPM 9.3.8, "Control Rod Insert and Withdrawal Timing." At 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />, control rod friction testing commenced in accordance with Maintenance Procedure PPM 10.24.17, "CRD Oscilloscope dp Testing." Although the control rod timing and friction tests require rod withdrawal, Control Rods "10-11" and "26-35" remained out of service. Repair of their scram accumulator level switches had not been completed. In addition, several other control rods were out of service for PPM 7.4.1.3.5.2 accumulator surveillance testing, which was still in progress.

Due to simultaneous control rod maintenance, accumulator surveillance testing, and timing and friction testing, Operations personnel returned Control Rods "10-11" and. "26-35" to service without their scram accumulator level switches having been repaired. Furthermore, the faulty scram accumulator level switches were left in a condition that failed to actuate the accumulator trouble alarm or. the respective Full Core Display accumulator trouble light. Thus, Operations personnel at the HCUs were not alerted of their error and had no reason to suspect the two control rods were inoperable. Consequently, the Control Room Inoperable Equipment Log was not consulted and the control rods were mistakenly verified as operable.

The two control rods were subsequently each withdrawn twice with their scram accumulator level switches inoperable, once for rod timing and once for friction testing.

LICENSEE EVENT REPC (LER)

TEXT CONTINUATION AGILITY KAME (1 j OOCKET HUMBER (2) LER KUMBER (8) AGE (3)

Year umber ev. Ho.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 2 2 0 3 F 5 1TLE (4)

TWO CONTROL RODS WERE WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE The two control rod withdrawal events were evaluated by the responsible System Engineer and Licensing.

It was determined that the plant had violated Technical Specification 3.1.3.5. The failed scram accumulator level switches caused the associated scram accumulators to be inoperable. By Technical Specification Action Statement (TSAS) 3.1.3.5.b.1, the control rods with inoperable scram accumulators should have remained inserted. As a result, Problem Evaluation Request (PER) 293-709 was initiated on May 26, 1993.

Immediate Corrective Actions On May 25, 1993, at 2230 hours0.0258 days <br />0.619 hours <br />0.00369 weeks <br />8.48515e-4 months <br />, Plant Operators disarmed HCUs "10-11" and "26-35" hydraulically.

Further Eval tion and orrective Action A. Further Evaluation

1. This event is reportable pursuant to 10CFR50.73(a)(2)(i)(B) as -"Any operation or condition prohibited by the plant's Technical Specifications...."
2. HCUs are declared inoperable on a routine basis during refueling outages as a result of control rod surveillances and maintenance. However, none of the associated procedures caution the user not to withdraw an inoperable control rod or a control rod with an in'operable scram accumulator. Furthermore, there are no procedural controls to ensure that an inoperable control rod or scram accumulator is disarmed.
3. As stated above, HCUs "10-11 "and "26-35" were declared inoperable when their scram accumulators became technically inoperable for failed limit switches. They were listed in the Control Room Inoperable Equipment Log, but were not disarmed. Control Room Operations personnel were aware that TSAS 3.1.3.5 applied, but did not recognize that they should enter

, Action b.1. Since the control rods with inoperable scram accumulators were fully inserted, the action statement "With one withdrawn control rod with its associated scram accumulator inoperable..." was interpreted such that the specified condition was not thought to have been met. Consequently, the action statement was not entered and no action was taken to "disarm the associated directional control valves within one hour...." If the action had been taken, this event most likely would have been prevented.

LICENSEE EVENT REPOO(LER)

TEXT CONTINUATION ACILITY NAHE (1) OOCKET NUHBER (2) LER NUHBER (8) AGE (3) ear umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 2 2 0 4 F 5 ITLE (4)

TWO CONTROL RODS WERE'WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE B. ~Rg~a~ue There were two root cases of this event;

1. Plant procedures did not provide guidance to assure that inoperable control rods are disarmed.
2. The faulty scram accumulator level switches were not repaired in a timely manner.

C. Fu her Correc ive Action

1. Revise PPMs selected by Reactor Engineering on the basis of potentially causing or identifying an inoperable control rod by August 31, 1993. The selected procedures will be revised to reference the applicable TSAS and provide direction to disarm an inoperable control rod in accordance with PPM 2.1.1, "Control Rod Drive System."
2. Revise PPM 7.4.1.3.5.2 by August 31, 1993, to provide direction for the procedure user to immediately notify the Shift Manager to initiate a Priority 1 MWR if a faulty scram accumulator level switch is identified.
3. This LER will be required reading. for Operations personnel, and the reading is to be completed by September 30, 1993.
4. This event will be included in the Annual Refueling Outage industry events training for Operations personnel.

~f' if'uring this event, the plant was in the Refueling Mode with the Reactor Mode Switch in the "Refuel" position. In this condition, plant design limits control rod movement to one rod at a time. The withdrawal of one control rod will not reduce shutdown margin below the Technical Specification 3.1.1 limits. This ensures that a sufficient shutdown margin exists for the reactor to be maintained sufficiently subcritical to preclude inadvertent criticality in the shutdown condition. Since minimum shutdown margin was maintained, this event was determined to have had no safety significance, and posed no threat to the health and safety of either the public or plant personnel.

imilar Even LER 92-011 reported an event where the procedural method of disarming an inoperable control rod did not meet TSAS requirements. The root cause of this event was a less than adequate plant procedure. The corrective actions consisted of.correction of the procedural deficiency and Quality Action Team recommendations for improvements in Technical Specification compliance.

LICENSEE EVENT REPC (LER)

TEXT CONTINUATION ACILITY NAHE (I) DOCKET NUHBER (2) LER NUHBER (8) AGE (3) ear umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 2 2 0 5 F 5 ITLE (4)

TWO CONTROL RODS WERE WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE EII Inf rm i n T~it i EIIS Reference

~tern ~om o~nen Control Rod Drive System AA Control Rod AA ROD Scram Accumulator AA ACC Scram Accumulator Level Switch AA LS Hydraulic Control Unit (HCU) AA HCU

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