ML17291A219

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LER 93-022-01:on 930524,two Control Rod Withdrawal Events Were Identified as Having Violated Ts.Caused by Control Rod Maintenance & Testing Not Sufficient.Sys to Improve HCU & Control Rod implemented.W/940714 Ltr
ML17291A219
Person / Time
Site: Columbia Energy Northwest icon.png
Issue date: 07/14/1994
From: Mackaman C, Parrish J
WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-94-161, LER-93-022, LER-93-22, NUDOCS 9407190333
Download: ML17291A219 (10)
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Text

PRIDRIWY (ACCELERATED Rl DS 8 ROCESSIii'G) 1 REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9407190333 DOC.DATE: 94/07/14 NOTARIZED: NO DOCKET N FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION MACKAMAN,C.D. Washington Public Power Supply System P PARRISH,J.V. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 93-022-01:on 930524,two control rod withdrawal events were identified as having violated TS.Caused by control rod maintenance & testing not sufficient.Sys to improve HCU & 0 control rod implemented.W/940714 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

ENCL i SIZE: 7 NOTES RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PDIV-3 PD 1 1 CLIFFORD,J 1 1 INTERNAL: ACRS 1 AEOD/DS P/TPAB 1 1 AEOD/ROAB/DSP 2 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 NRR/DORS/OEAB 1 1 NRR/DRCH/HHFB 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 NRR/DRSS/PRPB 2 2 NRR/DSSA/SPLB 1 ~RR/ DSSA/.SRXB

~REG~LEM 02 1 1 1

NRR/PMAS/IRCB-E 1 1 D

RES/DSIR/EIB RGN4 FILE 01 1 1 EXTERNAL EG&G BRYCE F 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 C

U NOTETOALL'RIDS"RECIPIENTS:

PLEASE HELP US TO REDUCE iVASTE! CONTACTTHE DOCUMENT CONTROL DESK, ROOM PI-37 (EXT. 504-2083 ) TO ELIhll14ATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEEDl FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 27 ENCL 27

WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington. Way ~ Richland, Washington 99352 July 14, 1994 G02-94-161 Docket No. 50-397-Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

NUCLEAR PLANT %NP-2, OPERATING LICENSE NPF-21 LICENSEE EVENT REPORT NO. 93-022-01 Transmitted herewith is Licensee Event Report No. 93-022-01 for WNP-2. This is a revision to the report submitted on June 25, 1993 in response to the reporting requirements of 10CFR50.73 and discusses the items of reportability, corrective action taken, and action taken to preclude recurrence.

This revision is being submitted to address the issues raised by the NRC Resident Inspector concerning the Control Room Inoperable Equipment Log, personnel accountability, and proper interpretation of Technical Specifications. In response to these concerns, this event was reinvestigated and resulted in changes to the Abstract, Event Description, Further Evaluation, and Similar Events sections, including the root causes and corrective actions.

These changes are indicated by revision bars in the right-hand margin.

Although the corrective actions have been changed in this revision, the original corrective actions are considered to be enhancements and will be completed as originally committed.

Qv 940729033~ 940734 PDR ADOCK 05000~97 8 PDR PJ& (

USNRC Page 2 NUCLEAR PLANT %NP-2, OPERATING LICENSE NPF-21 LICENSEE EVENT REPORT NO. 93-022-01 Should you have any questions'or desire additional information, please call me or D.A. Swank at (509) 377-4563.

Sincerely,

. V. Parrish (Mail Drop 1023)

Assistant Managing Director, Operations JVP/CDM/la Enclosure CC: LJ Callan, NRC-RIV KE Perkins, Jr., NRC RIV, Walnut Creek Field Office NS Reynolds, Winston & Strawn NRC Sr. Resident Inspector (Mail Drop 927N, 2 Copies)

INPO Records Center - Atlanta, GA DL Williams, BPA (Mail Drop 399)

LlCENSEE EVEIOREPORT (LER)

ACILITY NAME (I) , DOCKET NUMB R ( ) PAGE (3)

Mashin t()n Nuclear Plant - Unit 2 0 5 0 0 ~

0 3 9 7 I OF ITLE (4)

TWO CONTROL RODS WERE WZI'HDRAWNWITH THEIR SCRAM ACCUMULATORS INOPERABLE EVENT DATE (5 LER NUMBER 6 REPORT DATE 7) OTHER FACILITIES INVOLVED (8 HOHTH DAY YEAR YEAR ,:<', SEQUENTIAL EV I 5 ION MONTH DAY YEAR FACILITY NAMES CKE NUMB R (5)

>'i", NUMBER 'UMBER Kc, 0 5 0 0 0 5 2 4 9 3 9 3 0 2 2 0 1 0 7 I 4 9 4 0 5 0 0 PERATING HIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check one or more of the fol1owing) (ll)

ODE (9) 5 OWER LEVEL'.402(b) 0.405(C) 50.73(a)(2)(iv) 77.71(b) 0.405(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 0.405(a)(1)(iii) 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) e1ow and in Text, NRC 0.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B) Form 366A) 0.405(a)(1)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x)

LICENSEE CONTACT FOR THIS LER 12 TELEPHONE NUMBER C. D. Mackaman, Licensing Engineer REA CODE 5 0 9 7 7 - 4 4 5 1 COMPLETE ONE LINE FOR EACH COHPOHEHT FAILURE DESCRIBED IH THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFACTURER EPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER EPORTABLE !>'j<+c 0 HPRDS TO HPRDS .:i~c<<>

SUPPLEHEHTAL REPORT EXPECTED (14) EXPECTED SUBMISSIOH MONTH DA'Y YEAR ATE (15)

YES (If yes, complete EXPECTED SUBMISSIOH DATE) HO TRACT ROJ 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 water 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.'he root causes for this event were: (1) the Shift Managers failed to fully evaluate Technical Specification requirements and actions to assure compliance, and (2) the methods used to indicate the status of HCU and control rod maintenance and testing activities were not sufficiently effective to coordinate the concurrent activities.

LICENSEE EVENT REPORT R)

TEXT CONTINUATION AGILITY NAHE (,1) DOCKET NUHBER (2) LER NUHBER (8) AGE (3) umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 22 01 2 F 5 ITLE (4)

TWO CONTROL RODS WERE WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE i

Further corrective actions include: (1) action by Operations management to emphasize the importance of a thorough review of Technical Specification requirements and actions to assure compliance, (2) implementation of a system to improve HCU and control rod status control, (3) action by Operations management to reinforce proper techniques for review of the Control Room Inoperable Equipment Log and strengthen Shift Manager turnovers, and (4) counseling of the Operations personnel involved in this event.

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

Rlldi i m Power Level - 0%

Plant Mode - 5 (Refueling) vn De ri in 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 water 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 the faulty scram accumulator level switches found during the performance of 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 faulty 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 (dp) testing commenced in accordance with Maintenance Procedure PPM 10.24.17, "CRD Oscilloscope dp Testing." The faulty scram accumulator level switches were left in a condition that did not actuate the accumulator trouble alarm or the respective Full Core Display accumulator trouble light. Thus, Operations personnel were not alerted by the alarms of the faulty level switches and inadvertently withdrew Control Rods "10-11" and "26-35" for testing without their scram accumulator level switches having been repaired. The two control rods were each withdrawn twice, once-for rod timing and once for friction testing.

LICENSEE EVENT REPORTER)

TEXT CONTINUATION

~ ACILITY NAME (1) OOCKET NUNBER (2) LER NUNBER (B) AGE (3)

Year umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 022 1 3 F 5 ITLE (4)

TWO CONTROL RODS WERE WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE The Control Room Inoperable Equipment Log correctly identified the two control rod HCUs as inoperable; however, the rod status was not clearly discernable using the Log during the refueling outage conditions because of the large number of control rods (185) and the impact of concurrent control rod and HCU maintenance and testing activities. The Shift Managers on shift at the time were not aware that the HCUs were listed in the Inoperable Equipment Log, although they had reviewed the Log at shift turnover.

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.l, the control rods with inoperable scram accumulators should have remained inserted. As a result, Problem Evaluation Request (PER) 293-0709 was initiated on May 26, 1993 ~

Immedia e rrec ive Ac i n 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 in accordance with TSAS 3.1.3.5.b.l.b.

Fu her Ev lu i n n orrective Action A. Further Ev 1 i n

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. Typically, a bank of 20 control rods are removed from service for maintenance activities. When the maintenance work is complete, the bank of 20 control rods is returned to service for timing and friction testing. Concurrent with this functional and operational testing, another bank of 20 control rods is removed from service for maintenance. In this case, a bank of 20 control rods was out of service to perform accumulator surveillance testing and several additional control rods were out of service for repairs, including the two control rods with faulty scram accumulator level switches. When the surveillance testing was completed, the faulty level switches had not yet been repaired and there was no, visible indication of the problem. In addition, the methods for coordinating control rod maintenance and testing activities proved ineffective for indicating the level switch repair status.

Consequently, the two control rods with faulty scram accumulator level switches were inadvertently returned to service with the bank of 20 control rods being returned to service for timing and friction testing following routine maintenance, If the Control Room Operators had.

been aware that the two faulty scram accumulator level switches had not been repaired, they would not have returned the associated control rods to service.

LICENSEE EVENT REPORTR)

TEXT CONTINUATION

~ AGILITY NAME (i) DOCKET NUMBER (2) LER NUMBER (8) AGE (3)

Year '(umber ev. No.

Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 022 01 4 F 5 ITLE (4)

TWO CONTROL RODS WERE WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE

3. As stated above, HCUs "10-11 "and "26-35" were declared inoperable when their scram accumulators became technically inoperable because of faulty level 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 interpret the Technical Specification such that they should'enter Action b.1 and disarm the inoperable control rods.

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 by Operations personnel such that the specified condition was not met. Consequently, the action statement was not entered and no action was taken to "disarm the associated directional control valves within one hour...." Since this action was not taken, Clearance tags were not hung on the HCU directional control valves. The tags would have prohibited restoration of the HCUs to operable status until the Clearance initiating condition (faulty scram accumulator level switches) was corrected.

B.

The root causes for this event were: (1) the Shift Managers failed to fully evaluate Technical Specification requirements and actions to assure compliance, and (2) the methods to indicate the status of HCU and control rod maintenance and testing activities were not sufficiently effective to .

coordinate the concurrent activities.

A contributing cause for this event was that, during the aggressive pace of plant outage conditions, the Shift Managers tend to focus only on changes to the Control Room Inoperable Equipment Log during shift turnover reviews.

C. hr rr iv A in

1. Operations management has emphasized the importance of a thorough review of Technical Specification requirements and actions to assure compliance.
2. A system to improve HCU and control rod status control has been implemented.
3. Operations management has reinforced proper techniques for review of the Control Room Inoperable Equipment Log and strengthened Shift Manager turnovers.
4. The Operations personnel involved in this event have been counseled on Operations Management expectations for: (1) status controls for inoperable control rods, (2) review of the Control Room Inoperable Equipment Log, and (3) shift turnover and communications.

4 LICENSEE EVENT REPORT R)

TEXT CONTINUATION ACIL1TY KAHE (1) DOCKET NUHBER (2) LER NUHBER (8) AGE (3)

Year umber ev. No.

'Washington Nuclear Plant - Unit 2 0 5 0 0 0 3 9 7 3 22' 5 F 5 1TLE (4)

TWO CONTROL RODS WERE WITHDRAWN WITH THEIR SCRAM ACCUMULATORS INOPERABLE fe i nifi n During 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.

imi)ar Even LER 93-005 reported an event where inadequate documentation and pre-startup reviews resulted in plant operation with two Containment Purge Exhaust (CEP) Valves having leakage in excess of Technical Specification requirements. A root cause for the event included the failure to document in the Control Room Inoperable Equipment Log that repair of the CEP valves was a Technical Specification maintenance requirement and a plant startup restraint, Consequently, the pre-startup review of the Log did not identify the requirement. As a result, the plant was inadvertently started-up and operated in a Technical Specification noncompliance condition. The corrective actions for the event focused on improving documentation and strengthening pre-startup reviews. These corrective actions would not be expected to prevent the conditions described in this LER.

EII Inf rm i n Text Ref ren e f

$y.'gem ~mixen 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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