ML17286B086

LER 91-023-00:on 910906,HPCS Sys Pump Suction Switchover from Condensate Storage Tanks to Suppression Pool Occurred During Maint Testing.Caused by Incomplete Planning & Scheduling.Operators Realigned HPCS suction.W/911007 Ltr

ML17286B086
Person / Time
Site:	Columbia
Issue date:	10/07/1991
From:	Arbuckle J, John Baker WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-023, LER-91-23, NUDOCS 9110160214
Download: ML17286B086 (8)

Text

ACCELERATED DIRIBUTION DEMONSTRATION SYSTEM k

5 REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9110160214 DOC.DATE: 91/10/07 NOTARIZED: NO DOCKET FACIL:50-397 WPPSS Nuclear Project, Unit 2, Washington Public Powe 05000397 AUTH. NAME AUTHOR AFFILIATION ARBUCKLE,J.D. Washington Public Power Supply System BA'KER,J.W. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 91-023-00:on 910906,HPCS sys pump suction switchover from condensate storage tanks to suppression pool occurred during maint testing. Caused by incomplete planning & D scheduling. Operators realigned HPCS suction.W/911007 ltr.

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

2 SIZE:

NOTES:

RECIPIENT COPIES RECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 ENG,P.L. 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/DET/ECMB 9H 1 1 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB1 0 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB SD 1 1 NRR/DST/SICBSH3 1 1 NRR/DST SPLBSD1 1 1 NRR/DST/SRXB SE 1 1 REG I 1 1 RES/DSIR/EIB 1 1 RGN5 1 1 EXTERNAL: EG&G BRYCE,J.H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POOREPW 1 1 NUDOCS FULL TXT 1 1 A

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE iVAS fE! CONTACT THE DOCUMENT CONTROL DESK, ROOi~i P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAiVIE FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 33 ENCL 33

WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George LVashington 'i1'ay ~ Richland, Ivashington 99352 Docket No. 50-397 October 7, 1991 Document Control Desk U.S. Nuclear Regulatory Commission Hashington, D.C. 20555

Subject:

NUCLEAR PLANT NO. 2 LICENSEE EVENT REPORT NO.91-023

Dear Sir:

Transmitted herewith is Licensee Event Report No.91-023 for the HNP-'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.

Very truly yours, J. H. Baker HNP-2 Plant Hanager

Enclosure:

Licensee Event Report No.91-023 cc: Hr. John B. Hartin, NRC Region V Hr. C. Sorensen, NRC Resident Inspector (H/D 901A)

INPO Records Center Atlanta, GA Hs. Dottie Sherman, ANI Hr. D. L. Hilliams, BPA (H/D 399)

NRC Resident Inspector walk over copy 9:lj01602g4 9i)007 05000397 PDR ADvCK F'DR

NHC FOAM 366 U.S. NUCLEAR REGULATORY (X)MMISSION APPAOVEO OMB NO. 31500104 (669)

EXPIRES; 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LERl COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P630), U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503, FACILITY NAME (ll DOCKET NUMBER (2) PA E 3I 0 5 0 0 0 1 OF

""'A"igh Pressure Core Spray (HPCS) System Pump Suction Valve Switchover Actuation

.Durin Maintenance Testin Oue to Less Than Ade uate Plannin and Schedulin EVENT DATE (5) LER NUMBER (5) REPORT DATE (7) OTHER FACILITIES INVOLVED (0)

OAY YEAR YEAR i~<"'> SEQUENTIAL 'arear IIEvsloN MONTH DAY YEAR FACILITYNAMES DOCKET NUMBER(S)

MONTH NUMBER NUMBER 0 5 0 0 0 0 9 06 91 91 023 0 10 07 0 (ll) 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T 0 THE RtQUIREMENTS OF 10 CFA (Ir IChrtfr one or more of thr IollowinP)

OPERATING MODE (0) 20.402(B) 20.405(c) 60.73( ~ ) (2) liv) 73.71(B)

POWER 20.405( ~ ) Ill(il 60.30(cl(1) 60.7 3(e H2)( vl 73.71(c)

LEYEL 0 0 0 20AOS( ~ )(I)(0) 60.36 (c) l2) 50,73(e) (2) (vii) OTHER ISprcify in Ahrtrrct priow end In Tert, HRC Form 20.405(e ) ll) (iii) 60.73( ~ ) (2) (i) 60.73(e ) (2) (vitI) (Al 36SAI 20.405 (e I (1) (iv) 50.73( ~ ) l2)(ii) 50.73(el(2)(viiil(BI 20.405(el(ll(v) 50,73(e l(2) (iii) 50,73( ~ ) (2) (x I LICENSEE CONTACT FOR THIS LER (12I NAME TELEPHONE NUMBER AREA CODE J. 0. Arbuckle 'om liance COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

IVIANUFAC. REPORTABLE MANUFAC. REPORTABLE CAUSE SYSTtM COMPONEtvT TURER TO NPAOS Srrr)@ger. e terr c*UEE SYSTEM COMPONENT TURER TO NPRDS

%QAV MONTH DAY YEAR SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED SUBMISSION DATE ASI YES Ilfyrt comPIetr EXPECTED SVShtISSIOII DATEI NO ABsTRACT ILImlt to tr00 tprcrr. I r., rpproximrrrly Bftrrn tinpir rprce typrwnttrn linNI (16)

Abstract On September 6, 1991 at 1218 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.63449e-4 months <br /> while the Plant was shutdown for an outage, a High Pressure Core Spray (HPCS) System pump suction switchover from the Condensate Storage 1'anks to the Suppression Pool occurred during maintenance testing.

Plant configuration at the time was such that HPCS suction was lined up to the Condensate Storage Tanks (CSTs) with CST Suction Valve HPCS-V-1 open and Suppression Pool Suction Valve HPCS-V-15 closed, the normal system lineup. The switchover, an Engineered Safety Feature (ESF) actuation, involved the automatic closure of HPCS-V-1 and the opening oF HPCS-,V-15.

At the time of the event Plant Instrument and Control ( IEC) Technicians were in the process of obtaining reference voltage readings on Condensate Storage Tank Level Switches HPCS-LS-3A and HPCS-LS-38. However, when the Plant IEC Technician connected the fi rst lead oF a voltmeter to HPCS-LS-3A the HPCS suction valves NRC Form 306 (660)

NAC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION

( (64)9) APPROVED OMB NO. 31504)(04 EXP IR ES: 4/30/92 LICENSEE EVENT REPORT (LER) ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (F430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1HE PAPERWOAK REDUCTION PAOJECT (31600'I04). OFFICE OF MANAGEMENTANO BUDGET, WASHINGTON, DC 20503.

FACILITY NAME 0) DOCKET NUMBER (2) PAGE (3)

LER NUMBER (6)

YEAR >~6 SEQUENTIAL (Yh REVISION v494 NUMSER vxrvo NUMSER 0 5 0 0 0 O oF 0 5 TExT /// moro 4/>>oo /4 ror/Irked, ore odd/I/or>>/ ArRc Form 3564'4/ (17) transferred, apparently due to the shorting of adjacent pins on a 14-pin DIP Test Socket that was used to take the voltage readings. The cause of this event was incomplete planning and scheduling in that the job scoping did not identify special circumstances and conditions unique to the situation. As an immediate corrective action Plant Control Room Operators realigned the HPCS suction from the Suppression Pool to the Condensate Storage Tanks (HPCS-V-15 was closed and HPCS-V-1 was re-opened) ~

Further corrective action consists of 1) revising the calibration procedure for HPCS-LS-3A and HPCS-LS-38 to requi re the use of scaffolding, additional lighting and an appropriate test connector during performance of the calibration, and 2) discussing this LER in industry events training to emphasize the benefit and importance of performing a task hazard analysis prior to originating work instructions.

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

v Plant Conditions Power Level OX Plant Node - 4 (Cold Shutdown)

Event Oescri tion On September 6, 1991 at 1218 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.63449e-4 months <br /> a High Pressure Core Spray (HPCS) System pump suction switchover from the Condensate Storage Tanks to the Suppression Pool occurred during maintenance testing efforts. At the time, the Plant was shutdown for an outage.

I Plant configuration at the time was such that HPCS suction was lined up to the Condensate Storage Tanks (CSTs) with CSl Suction Valve HPCS-V-1 open and Suppression Pool Suction Valve HPCS-V-15 closed, the normal system lineup. The switchover, an Engineered Safety Feature (ESF) actuation, was the automatic closure of HPCS-V-1 and the opening of'PCS-V-15.

NRC Form 366A (64)9)

NRC FOAM 366A U.S. NUCLEAR AEGULATORYCOMMISSION APPROVED OMB NO. 31504104 (689)

EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REQUEST/ 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P$ 30), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555. AND TO 1HE PAPERWORK REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (11 DOCKET NUMBER (21 LER NUMBER (6) PAGE (3)

YEAR de SEQUENTIAL iP': REVISION st% NUMEEII S~S NUMBER 0 5 0 0 0 OF 1 ni 0 3 0 0 TEXT /// nxvs spsss /s rsqII)Isd, IIss sdd/doIM//Y/IC %%dnII 3664'4/ (17)

During the event period, Plant Instrument and Control ( II(C) Technicians were in the process of obtaining reference voltage readings on Condensate Storage Tank Level Switches HPCS-LS-3A and HPCS-LS-38. The voltage readings were being taken as part of an effort to verify a wet-to-dry switch response time of one second. When the Plant I8C Technician connected the first lead of the voltmeter to HPCS-LS-3A the HPCS suction valves transferred, apparently due to the shorting of adjacent pins on a 14-pin DIP Test Socket that was used to take the voltage readings, The closure of HPCS-V-1 and the opening of HPCS-V-15 was by Plant design and Plant Control Room Operators took appropriate action to realign the system to pre-event status.

Immediate Corrective Action Plant Control Room Operators responded by taking action to realign the HPCS Suction from the Suppression Pool to the Condensate Storage Tanks (HPCS-V-15 was closed and HPCS-V-1 was re-opened).

Further Evaluation and Corrective Action A. FurtIIer Evaluation

1. This event is reportable under 10CFR50.73(a)(2)(iv) as an event or condition that resulted in manual or automatic actuation of any Engineered Safety Feature.

2. There were no structures, systems or components that were inoperable at the start of the event that contributed to the event.

3. The circuit operation is such that the HPCS switchover logic is designed to actuate based on either low Condensate Storage Tank or high Suppression Pool levels. Level switches HPCS-LS-3A and HPCS-LS-38 are redundant, self-heated Resistance Thermal Oetectors (RTDs) that sense, the level of water in the Condensate Storage Tank (CST). They are installed at the top of a chamber in the HPCS suction line from the CSTs. When water in the sensing chamber falls below a specified level, indicating a low water level in the CSTs, the level switches will actuate to cause a suction valve transfer from the CSTs to the Suppression Pool.

NRC FoIm 366A (689)

QRC FORM 366A V.S. NUCLEAR REGULATORY COMMISSION (689) APPROVED OMB NO. 31500104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REQVESTI 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION ANO REPORTS MANAGEMENT BRANCH (P830), V.S. NUCLEAR REGULATORY COMMISSION,'WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT 131504)104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR SEOUENTIAL REVISION NUMBER NUMBER Washington Nuclear Plant Unit 2 0 5 0 0 0 3 7 9 1 2 3 0 4oF 0 5 TEXT /lfmorB 4P444 /4 ror/Irr)Bd, II44 Bddrrr/)IM//l/IC Form 3()54'4/ (17)

4. The cause of this event is Less than. Adequate Planning and Scheduling in that the job scoping did not identify special circumstances and conditions unique to the situation, or that an HPCS suction valve transfer may occur.

As a result of an Engineering review, it was determined that test documentation was not on file to verify a wet-to-dry switch response time of one second For HPCS-LS-3A and HPCS-LS-3B. The vendor (Fluid Components, Inc.) instruction manual for 'the level switches described a calibration method to meet the required response time by taking wet voltage readings and adjusting the switch to actuate at 80 millivolts below the wet value. However, the Plant Procedure For calibrating the level switches (PPN 10.27.23) did not,account for the response time or include specified parameters for that setpoint. In order to revise PPN 10.27.23 to describe the correct response time calibration method, it was necessary to obtain wet voltage readings to establish setpoint criteria.

Accordingly, a Nundane Task Request (NTR) was prepared to measure and record the level switch wet voltage readings on pins 6 (+) and 7 (-) of the 14-pin DIP Test Socket in HPCS-LS-3A and HPCS-LS-38.

Level switches HPCS-LS-3A and HPCS-LS-3B are located in a corridor, approximately 12 feet above the floor, in the Reactor Building. Lighting in the area is not optimum and the Plant I&C Technician reached the switches by means of a ladder.

.. The Plant I&C Technician taking the readings was to measure the voltages by clipping mini-grabber test clips to adjacent pins (6 and 7) on the 14-pin DIP Test Socket. The DIP Test Socket is a small rectangular unit that is held above the circuit board by 14 bare pins (approximately 1/16 inch apart). When the first mini-grabber was attached to pin seven, the suction valve transfer occurred, It is most likely that while attaching the mini-grabber pins 6 and 7 were shorted together; which would cause a transfer of the HPCS suction valves.

B. Further Corrective Action On September 7, 1991 the voltage readings were successfully obtained.

During this process, scaffolding and temporary lighting was used. In addition, Plant I&C Technicians had fabricated a special test plug, with meter leads soldered onto pins 6 and 7, that could be inserted into the test socket.

NRC FRNR 366A (989)

N)IC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (669) APPROVED OMB NO. 31600104 EXPIRES; 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REOUESTr 50.0 HRS, FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT (31604104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME O) DOCKET NUMBER 12) LER NUMBER (6) PAGE (3)

YEAR SEOVENTIAL AEvroroN NUMSEA NUMOEA Washin ton Nuclear Plant Unit 2 o s o o o 3 7 9 1 0 0 oFO 5 TEXT /// more 4/reoe /4 ier/oh/ed, oee edChr/orhel iVRC Form 3664'4/ (12)

2. Plant Procedure 10.27.23 will be revised to require the use of scaffolding, additional lighting and an appropriate test connector during performance of this calibration.

3. This LER wi 11 be discussed in Industry Events Training to emphasize the

., benefit and importance of performance of a task hazard analysis prior to originating work instructions.

Safet Si nificance There is no safety significance associated with this event. There was no actual Condensate Storage Tank level change, and the event was limited to a shorting of the level trip logic during testing. Furthermore, all systems operated as designed to cause the HPCS System pump suction valve switchover and Plant Control Room Operators responded by realigning the system to pre-event status. Although the HPCS System had been lined up and designated as part of the shutdown ECCS function when the event occurred, the Suppression Pool was available if needed. Accordingly, this event posed no threat to the health and safety of either the public or Plant personnel'imilar Events There have been LERs pertaining to HPCS suction valve transfers; however, none with a similar root cause.

EIIS Information EIIS Reference System Component High Pressure Core Spray(HPCS) System BG HPCS-V-1 BG HPCS-V-15 BG Suppression Pool NH Condensate Storage Tank KA TK HPCS-P-1 BG P HPCS-LS-3A BG LIS HPCS-LS-38 BG LIS NRC F orm 366A (64)9)