ML18012A158

LER 96-004-00:on 960205,RWST Level Transmitters Failed High Due to Freezing That Resulted in Entry Into TS LCO 3.0.3 & Subsequent Violation of TS Action Statement.Revised Procedure to Correct steps.W/960306 Ltr

ML18012A158
Person / Time
Site:	Harris
Issue date:	03/06/1996
From:	Donahue J, Prunty R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HNP-96-038, HNP-96-38, LER-96-004, LER-96-4, NUDOCS 9603110609
Download: ML18012A158 (11)

Text

CATEGORY 1 REGULRTOIOINFORMATZON DISTRIBUTION TEM (RIDE)

]I ACCESSION NBR:9603110609 DOC.DATE: 96/03/06 NOTARIZED: NO DOCKET t FACIL: 50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION PRUNTY,R.W. Carolina Power a Light Co.

DONAHUE,J.W. Carolina Power S Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 96-004-00:on 960205,RWST level transmitters failed high C due to freesing that resulted in entry into TS LCO 3.0.3 6 subsequent violation of TS action statement. Revised procedure to correct steps.N/960306 ltr.

DISTRIBUTION CODE. IE22T COPIES RECEIVED:LTR 1 ENCL l SIZE:

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

NOTES:Application for permit renewal filed. 05000400 g 0

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 PD 1 '1 LE,N 1 1 INTERNAL: ACRS 1 1 ALOD/NPD/RAB 2 2 AEOD/SPD/RRAB 1 1 CEDER~ 1 1 NRR/DE/ECGB 1 1 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 ~ 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 D RES/DSIR/EIB 1 1 RGN2 FILE 01 1 1 EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE I J H 2 2 NOAC MURPHYFG.A 1 1 NOAC POOREFW. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 l

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FULL TEXT CONVERS GN REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENC'6

h Carolina Power 8 Light Company Harris Nuclear Plant PO Box 165 New Hill NC 27562 NR 6 I996 U.S. Nuclear Regulatory Commission Serial: HNP-96-038 ATTN: NRC Document Control, Desk 10CFR50.73 Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCKET NO. 50-400 LICENSE NO. ViPF-63 LICENSEE EVENT REPORT 96-004-00 Gentlemen:

'n accordance with Title 10 to the Code of Federal Regulations, the enclosed Licensee Event Report is submitted. This report relates to a freezing event involving two Refueling Water Storage Tank (RWST) level transmitters, resulting in entry into Technical Specification Limiting Condition for Operation (LCO) 3.0.3, and a subsequent procedural error which caused a violation of a Technical Specification action statement.

Sincerely, J. W. Donahue General Manager Harris Plant RWP Enclosure c: Mr. S. D. Ebneter (NRC -'II)

Mr. N. B. Le (NRC - PM/NRR) iVrr. D. J. Roberts (NRC - IMP) 9603ll0609 960306 PDR ADOCK 05000400 S PDR j.lolll 1 New Hill NC I State Road 1134 II

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NRC FORM 366 U.S. N LEAR REGULATORY COMMISSION APPROVED BY OMB NO."3150-0104 ILSSI EXPIRES 04/30/98 ESTIMATED BURDEN PEA AESPONSE TO COMPLY WITH THIS MANDATORY INFOAMATION CO(lECTION REQUEST: 5M HRS. REPORTED lESSONS IEARNED ARE LXCENSEE EVENT REPORT (LER) INCOAPORATED UITO THE UCENSDIG PAOCESS ANO FEO BACK TO UIDUSTAT.

FORWAAO COMMENTS REGARDUIG BURDEN ESTIMATE TO THE INFORMATION ANO RECORDS h(ANAGEMENT BRANCH IT4) F33L US. NUClEAR REGUlATOAY COMMISSION.

(See reverse for required number of WASHINGTON. OC 20555OOOI, ANO TO THE PAPEA WORK REOUCTIN PROJECT 0150 digits/characters for each block) OI04h OFFICE OF MANAGEMENT ANO BUDGET, WASHINGTON. OC 205EL FACIUTY NAME (1) DOCKET NUMBER (2) PAOE (3)

Harris Nuclear Plant Unit-1 50-400 1 OF 4 TITLE (4)

Refueling Water Storage Tank (RWST) Level Transmitters failure high due to freezing, resulting in entry into Technical Specification LCO 3.0.3 and a subsequent violation of Technical Specification Action Statement.

EVENT DATE (5) LER NUMBER (6) . REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

FACIUTY NAME DOCKETNUMBER SEQUENTIAl REVISION f MONTH OAY YEAR MONTH OAY YEAR NUMBER NUMBER 05000 FACIUTY NAME DOCKET NUMBER 96 96 004 00 3, 6 96 05000 OPERATING THIS REPORT IS SUBMITTED PUR SUANT TO THE REQUIREMENTS OF 10 CFR 5: (Chock ono or moro) (11)

MODE (9) 20.2201(b) 20.2203(a) (2) (v) X 50.73(a)(2)(i) 50.73(a) (2) (viii) 20.2203(a) (1) 20.2203(a) (3)(i) 50.73(a) (2) (ii) 50.73(a) (2) (x)

POWER 100%

LEVEL (10) 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50.73(a) (2) (iii) 73.71 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv) OTHER 20.2203(a)(2)(iii) 50.36(c) (1) 50.73(a) (2) (v) Specify in Abstract below or in NRC Form 3BBA 20.2203(a)(2)(iv) 50.36(c) (2) X 50.73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER (Inciude Area Code)

R. W. Prunty, Jr., Project Engineer - Licensing/Regulatory Programs (919) 362-2030 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

EP AB REPORTAB(E CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER TO NPROS TO NPROS SUPPLEMENTAL REPORT EXPECTED <14) EXPECTED MONTH OAY YEAR YES SUBMISSION (If yos, complete. EXPECTED SUBMISSION DATE). DATE (16)

ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewrinen lines) (16)

On February 5, 1996 the plant was operating in Mode 1 with Reactor Power at 100%. At approximately 0335 Refueling Water Storage Tank (RWST) Level Transmitter i T-991 failed high due to a frozen sensing line and was declared inoperable. The transmitter was placed in the bypassed condition at 0418 to meet the Technical Specification Limiting Condition for Operation (LCO) 3.3.2 Action Statement ¹16. At approximately 0900 a second RWST Level Transmitter (LT-990) was also declared inoperable due to freezing. This resulted in the plant entering Technical Specification LCO 3.0.3, which requires action to bring the plant to a shutdown condition within seven hours. The level transmitter sensing lines were thawed. LT-990 was declared operable, and LCO 3.0.3 was exited at 1122. LT-991 was declared operable the following day (2/6/96) at 1406. The event was caused by freezing of the level transmitter sensing lines, caused by a combination of missing irisu(ation, heat trace not installed per design, and inappropriate insulation type for wet locations. Completed corrective actions included thawing the frozen lines, replacing missing insulation, and providing additional freeze protection guidance to Operations personnel. Future corrective actions include an upgrade of heat trace configuration and wattage and a change of insulation type and configuration.

Also on February 5, 1996, at approximately 1000, while restoring Main Control Board (MCB) indication, the bypassed condition on LT-991 required by the Technical Specification LCO was unknowingly removed because of a procedure error. This was identified the following day (2/6/96) during testing at approximately 0930. This resulted in a violation of LCO 3.3.2 Action Statement ¹16 for approximately 23.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. The cause of this condition was a procedural error in that the, step being performed to restore MCB indication did not recognize or acknowledge that the bypassed condition wo'uld also be removed.,Completed corrective actions include procedure revisions to correct the steps that caused the bypassed condition to be removed during trouble shooting and increased emphasis on Engineering technical review of selected procedures.

0 NRC FOAM 366A US. NUClEAR REGUlATORT COMMISSION (4 99I LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACIUTT NAME (II OOCKET lER NUMBER I6) PAGE I3)

SEOUENTIAl YEAR NUMBER NUMBER Harris Nuclear Plant ~ Unit I 50400 2 OF 4 96 - 004 - 00 TEXT Vf rooro spsco a roqvsod, oso odd reool copes ol NRC porro JVQI (I TI EVENT DESCRIPTION:

On February 5, 1996, the plant was operating in Mode 1 with reactor power at 100%. At approximately 0335 Refueling Water Storage Tank (RWST) Level Transmitter (EIIS Code BQ-LT) LT-991 failed high due to a frozen sensing line and was declared inoperable. The transmitter was placed in the bypassed condition at 0418 to meet Technical Specification Limiting Condition for Operation (LCO) 3.3.2 Action Statement ¹16. (This involved placing a Process Instrumentation Control (PIC) card bistable switch in the test position and lifting a lead/jumper.) This action changes the coincidence logic for the RWST Low-Low Level switchover sequence from 2 of 4 to 2 of 3.

At approximately 0815, a second RWST Level Transmitter (LT-990) indication started to trend upward due to a freezing sensing line. It went into high alarm at 0845 and was declared inoperable at approximately 0900. With only 2 of 4 channels operable, the plant was unable to comply with the LCO action statement. Thus, Technical Specification LCO 3.0.3 was entered, requiring action to bring the plant to a shutdown condition within the following seven hours. Initial investigation of this condition noted missing insulation on the transmitters'ensing line drains. External heating was applied to thaw the transmitters. At approximately 1122, LT-990 was satisfactorily channel checked and declared operable, thus exiting the LCO 3.0.3. LT-991 was declared operable at 1406 the following day (February 6, 1996) after a channel calibration was completed.

Also on February 5, 1996, at approximately 1000, while restoring Main Control Board (MCB) indication for transmitter LT-991, a procedure step returned the PIC card bistable switch to the normal position from the test position. This action removed the bypassed condition of LT-991, violating the Technical Specification LCO 3.3.2 Action Statement ¹16. (The procedure was incorrect in stating that the step could be completed to allow trouble shooting without affecting the bypassed condition of the instrument. The procedure error was introduced during a November 1995 revision.) At approximately 0930 on February 6, 1996, maintenance personnel identified the procedure error and restored the channel to the bypassed condition as required. by the LCO. The LCO action statement was violated for approximately 23.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. As noted above, LT-991 was declared operable at 1406 on February 6, 1996.

CAUSE:

The cause of the transmitter freezing event was a combination of ineffective construction controls which resulted in heat trace not being installed per design, failure to restore insulation after maintenance, and insulation type not being adequate for wet locations. The significance of missing insulation was not sufficiently understood.

Additionally, Operations personnel did not act sufficiently to prevent freezing of the second transmitter sensing line.

The cause of the procedure error was inadequate self checking during the revision process to ensure that the intended action was correct, including not referencing required drawings.

KRC FORM 366A US. NUCLEAR REGULATORT COMMISSION (496)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACIUTT NAME (I) OOCKET LER NUMBER (6) PAGE (3)

SEOUBITU(L REYLSION TEAR NUMBER NUMBER Harris Nuclear Plant Unit I SO.4OO 3 OF 4 96 - 004 OO TEXT pl more speceis reevied, vse eddaiooel copies ol NRC Form 36QI ill)

SAFETY SIGNIFICANCE:

There were no adverse safety consequences as a result of this event. The loss of two RWST level transmitters minimizes the redundancy of the inputs that initiate the RWST Low-Low Level switchover sequence. With two of the transmitters not in service, the 2 of 4 coincidence logic was not available. However, the two remaining operable transmitters were capable of initiating the RWST Low-Low Level switchover sequence if required. Additionally, when required, the Emergency Operating Procedure (EOP) network directs operators to take action to manually initiate the switchover. When the bypass was unknowingly removed from LT-991, the Low-Low Level switchover logic was restored to the original 2 of 4 coincidence logic. An Engineering Evaluation of LT-991 has concluded that the instrument was functional and that the instrument loop was capable of performing its intended safety function when its MCB indication was restored by returning the switch to the normal position.

These events are being reported per 10CFR50.73(a)(2)(i) and 10CFR50.73(a)(2)(vii).

PREVIOUS SIMILAR EVENTS:

There have been no LERs which have resulted in the simultaneous loss of more than one RWST level transmitter.

However, there were prior freeze events associated with individual RWST level transmitters in 1987, 1989, 1994, and 1995. Prior corrective actions were ineffective because they focused on the transmitters themselves and failed to detect the source of the problem in the sensing line drain.

Regarding the incorrect procedure, LER 95-009 was submitted November 3, 1995, relating to the unanticipated actuation of Engineered Safety Features (ESF) components during Refueling Outage ¹6. Corrective action included the, revision of the procedure review and approval process (Plant Procedure AP-006) to specify the use of multi-discipline technical reviews when warranted. The AP-006 revision was approved in the same time frame (November 1995) as the RWST procedure revision. Thus the corrective action to utilize the multi-discipline technical reviews was not incorporated into the RWST procedure revision whi'ch caused this event. Additionally, an Operations root cause investigation into human performance issues (CR 95-01474) identified inappropriate procedure revisions.

Corrective actions are still in progress.

CORRECTIVE ACTIONS COMPLETED:

1 ~ Missing insulation was replaced and the sensing lines were thawed.

2. Plant history was reviewed for previous freezing problems, and a walkdown of critical components was performed to identify potential short term freezing concerns. The results of the observations were provided to Operations, and an Operations Night Order was subsequently issued.

3. The OWP-ESF procedure was corrected by removing the steps that caused the bypassed condition of the level channel to be inadvertently removed. 8

4. Disciplinary action has been taken for the incorrect procedure change.

5. 'he OWP-ESF procedure was revised to allow restoration of MCB indication for trouble shooting while still maintaining the channel in the bypassed condition.

1 i(

NRC fORM 366A U.S. NUCLEAR REGULA'rORT COMMISSION

)4-SS)

LICENSEE EVENT REPORT (LEB)

TEXT CONTINUATION fACIUTT NAME 111 OOCKET LER NUMBER )6) PAGE Q)

SEOUENTIAL RETISION

'rEAR NUMBER NUMBER Harris Nuclear Plant ~

Unit I 60400 4 OF 4 96 - 004 - 00 TEXT /II moio spscois sofvied. vso sddnmos! copies oi A'RC Foram 36as) I)7)

CORRECTIVE ACTIONS COMPLETED cont:

6. Operations procedure changes which require a review by Engineering prior to approval have been identified.'he adverse weather procedure (AP-301) was revised to incorporate appropriate recommendations related to RWST level transmitter insulation verification and use of temporary external heat sources.

8. An Event Review Team has been established to determine other actions required to ensure future Operations procedure revisions are correct.

CORRECTIVE ACTIONS PLANNED:

1. The heat trace configuration and wattage will be upgraded, the insulation type will be changed to a type that will not absorb water, and the insulation configuration will be changed to better allow for removal/replacement by August 31, 1996.

2. Appropriate maintenance surveillance tests will be revised to include verification that drain valve insulation is reinstalled by April 8, 1996.

3. The adverse weather procedure (AP-301) will be further revised to incorporate priority equipment identification and control and more specific walkdown/inspection guidance by April 8, 1996. A requirement to perform an annual self assessment of operating experience/lessons learned from the previous year at HNP and the industry will also be included in this revision.

Operator Rounds Guidance regarding RWST pit pump/drain down prior to the water level reaching the transmitter sensing line insulation will be revised and issued to appropriate Operations personnel by March 15, 1996.

Implementation procedures for complying with Technical Specification action statements related to the Engineered Safety Features Actuation System, Reactor Protection System, and Radiation Monitoring System will be reviev.ed by April 8, 1996.

6. Recently revised surveillance procedures with a quarterly frequency or longer will be reviewed for technical accuracy prior to next performance. This action will continue until the Event Review Team discussed in Corrective Actions Completed Item ¹8 above presents its findings.

EIIS CODES:

Refueling Water Storage Tank (RWST) Level Transmitter (BQ-LT)