ML17286A906

LER 91-015-00:on 910602,high HPCS Sys Pump Suction Switchover from Condensate Storage Tanks to Suppression Pool Occurred.Caused by Personnel Error.Operator Involved Ack & Reset alarm.W/910628 Ltr

ML17286A906
Person / Time
Site:	Columbia
Issue date:	06/28/1991
From:	Arbuckle J, John Baker WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-91-125, LER-91-015, LER-91-15, NUDOCS 9107050214
Download: ML17286A906 (10)

Text

l, REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9107050214 DOC.DATE: 91/06/28, 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 BAKER,J.W. Washington Public Power Supply System RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 91-015-00:on 910602,high HPCS sys pump suction switchover from condensate storage tanks to suppression pool D occurred. Caused by personnel error. Operator involved ack &

reset alarm. W/910628 ltr.

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

NOTES: A RECIPIENT COPIES RECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 D ENG, P. L. 1 1 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/LHFB10 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 N~D LB8D1 1 1 NRR/DST/SRXB 8E 1 1 REG FILE 02 1 1 RES/DSIR/EIB 1 1 LE 01 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 POORE,W. 1 1 NUDOCS FULL TXT 1 1 D

D D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE ~VASTE! CONI ACT fHE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. X079) TO i'LIMINAI E YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

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

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WASHINGTON PUBLIC POWER SUPPLY SYSTEM P.O. Box 968 ~ 3000 George Washington Way ~ Richland, Washington 99352 G02-91-125 Docket No. 50-397 June 28, 1991 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

NUCLEAR PLANT NO. 2 LICENSEE EVENT REPORT NO.91-015

Dear Sir:

Transmitted herewith is Licensee Event Report No.91-015 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.

Very truly yours, J.W. Baker (M/D 927M)

WNP-2 Plant Manager JWB:ac

Enclosure:

Licensee Event Report No.91-015 cc: Hr. John B. Martin, NRC Region V Hr. C. J. Bosted, NRC Site (M/D 901A)

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

'~1070502) g PDR ADOCK O.,ot43O7

, PDR

NRC FORM 366 U.S. NUCLEAR 4EGULATORY COMMISSION (668) APPROVEO OMB NO. 3)SOO(04 EXPIRES: 4/30/92 I'IMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REOUESTI 50.0 HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN ESTIMATE TO THE RECOADS AND AEPORTS MANAGEMENT BRANCH (F630), U.S. NUCLEAR RFGULATOAY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (I) DOCKET NUMBER (2) PAGE 3 Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 39 71 oF 06 TITLE (4)

High Pressure Core Spray (HPCS) System Pump Suction Valve Switchover Actuation on Hi h Su ression Pool Level due to Personnel Error FVENT DATE(5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR gart SEQUENTIAL REVIStGN MONTH OAY YEAR FACILITYNAMFS DOCKET NUMBER(S)

NUMBER 0 5 0 0 0 0 2 1 9 1 1 5 0 0 89 1 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T0 THE 4LQUIREMENTS OF 10 CF 4 (): /Chrch one or morr of the Iollovrinp/ (11)

OPERATING MODE (8) 4 20.402(8) 20.405(cl 60.73(al(2)(iv) 73.71(II)

POWER 20A05( ~ l(1) (I) 6048(cl(1 I 50,73(a)(2)(v)l(vill)(A) 73.71(cl LEYEL 0 0 20.405 (a ) (I ) (ii) 50.38(c)(2) 50,73(a)(2)(vill OTHER /Sprcily /n Attttrect INlovr rnd In Tent, NRC Form 20.405(a l(1) (iii) 50.73(a ) (2) Ii) 50.73(v ) (2 36$ A/

ra((arpr)L/t 20AOS( ~ )(1)(iv) 50.73(a) (2) (8) 50.73(al(2)(viiil(B) 20A05 (a I (1)(vl 60.73(a l (2)(iii) 50.73( ~ ) (2)(a I LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMSFR AREA CODE J. D. Arbuckle Com liance En ineer 5 0 3 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESC4IBED IN THIS 4EPORT (13) p" P?n birr ".n3.

CAUSE SYSTEM COMPONENT MANUFAC. EPORTABLE i@5K~r@P44 4~< CAUSE SYSTEM COMPONENT MANUFAC EPORTABLE TUAER TO NPRDS g?PM)@~ TUAER TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONTH IÃ% DAY YEAR SUBMISSION DATE (15I YES IIIyrL comPlrtr EXPECTED SIIShtISSIOII DATE/ NO ABST4ACT /Limit to te00 tprcrt, I r., rpproalmrtrly Iiltren tlnprr.apecr typrvrritNn linml (18)

On June 2, 1991 at 0106 hours0.00123 days <br />0.0294 hours <br />1.752645e-4 weeks <br />4.0333e-5 months <br /> while the Plant was shutdown for maintenance, a High Pressure Core Spray (HPCS) System pump suction switchover from the Condensate Storage Tanks to the Suppression Pool occurred due to a Suppression Pool high water level condition.

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 (reference Figure 1).

The switchover, an Engineered Safety Feature (ESF ) actuation, was the automatic closure of HPCS-V-1 and the opening of HPCS-V-15.

During the event period, Plant Control Room Operators were lowering Reactor Vessel level through the Residual Heat Removal (RHR) HAH Heat Exchanger Vents to the Suppression Pool following excess Flow Check (EFC) Valve testing. During this period the Suppression Pool high level alarm annunciator had sealed in [the alarm annunciates at +0.5 inches (0.5 inches above normal pool level)j. However, after acknowledging and resetting the alarm, a Plant Control Room Operator failed to take action to either lower Suppression Pool level or manually switchover the HPCS suction valves as directed by procedure. When Suppression Pool water volume reached approximately +3.0 inches indicated level, the automatic switchover occurred.

NRC Form 386 (6691

APPROVED OMB NO. 3)500104 (64)9)

EXPIRES: 4/30/92 ATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EV REPORT (LER) IN RMATION COLLECTION REQUEST: 50A) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P4)30), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT (31504))04). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITYNAME (I) DOCKET NUMBER (2) LER NUMBER (8) PAGE (3)

YEAR SEQUENTIAL REVISION iS@ NUMBER 'A$> NUMSEIl Washington Nuclear Plant - Unit 2 o s o o o 3 79 1 015 0 00 2oF 0 6 TEXT /I/ moro opooo /4 ror/o/rod, ooo oddio'ooo///RC Form 36543/ (12)

Abstract (continued)

As an immediate corrective action Plant Control Room Operators took action to lower Suppression Pool level and then 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).

The cause of this event is personnel error in that the Plant Control Room Operator involved failed to follow procedures. Further corrective action consisted of counselling the Operator involved on procedural requirements and performance expectations, and including this LER for discussion during Licensed Operator Requalification Training.

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

Plant Conditions Power Level - OX Plant Mode - 4 (Cold Shutdown)

Event Descri tion On June 2, 1991 at 0106 hours0.00123 days <br />0.0294 hours <br />1.752645e-4 weeks <br />4.0333e-5 months <br /> a High Pressure Core Spray (HPCS) System pump suction switchover from the Condensate Storage Tanks to the Suppression Pool occurred while the Plant was shutdown for maintenance. The switchover occurred as the result of a Suppression Pool high water level condition.

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 (reference Figure 1).

The switchover, an Engineered Safety Feature (ESF) actuation, was the automatic closure of HPCS-V-1 and the opening of HPCS-V-15.

During the event period, Plant Control Room Operators were lowering Reactor Vessel level through the Residual Heat Removal (RHR) "A" Heat Exchanger Vents to the Suppression Pool following Excess Flow Check (EFC) Valve testing. During this period the Suppression Pool high level alarm (annunciator) sealed in [the alarm annunciates at + 0.5 inches (0.5 inches above normal pool level)j. Although the Plant Control Room Operator involved acknowledged and reset the alarm, he failed to take action to either lower Suppression Pool level, or manually switchover the HPCS suction valves as directed by procedure. When Suppression Pool water volume reached approximately +3.0 inches indicated level, the automatic transfer occurred. The Suppression Pool high level trip setpoint which would automatically cause a suction transfer is +5 inches. However, because the tolerance band (accuracy ) for the level instrumentation is plus or minus two inches, the automatic transfer could occur as low as +3 inches or as high as +7 inches.

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 lower Suppression Pool level.

NRC Form 3EEA (689)

)689) APPROVED 0MB NO. 31600)04 o EXP IR ES: 6/30/92 LICENSEE EVW REPORT ILER) ATED BURDEN PER RESPONSE TO COMPLY WTH THIS IN RMATION COLLECTION REQUEST: 508) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH IP430), U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT )31500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME I1) DOCKET NUMBER I2I LER NUMBER I6) PAGE I3I

SEQUENTIAL N.'UMBER 'O% re REVISION NUMBER Washington Nuclear Plant - Unit 2 o s o o o3 97 1 015 0 0 0 3oF TEXT /// moro a>>co /s ror/Ir/)od, Irso sdde'ono/NRC Form 3664's/ OT)

Immediate Corrective Action Plant Control Room Operators responded by taking action to lower Suppression Pool level and realigning 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. Further 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 the 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. Once initiated, the logic opens Suppression Pool Suction Valve HPCS-V-15. When HPCS-V-15 is full open, design logic closes Condensate Storage Tank Suction Valve HPCS-V-1. These valves are interlocked in this manner to prevent losing suction to pump HPCS-P-l.

There are two magnetically-activated float switches (HPCS-LS-2A and HPCS-LS-2B) that actuate on high Suppression Pool level. Because of the one-out-of-one logic, either switch can initiate opening of the Suppression Pool suction valve.

The cause of this event is Personnel Error due to Lack of Attention/Concentration. The Plant Control Room Operator involved failed to take appropriate and timely action to lower the Suppression Pool as directed by procedure when level is greater than +0.5 inches. Plant Annunciator Response Procedures (PPMs) 4.601.All and 4.601.A12, "Annunciator Panel Alarms" for Suppression Pool Level, require that when level is greater than +0.5 inches, Plant Control Room Operators are to either lower Suppression Pool level by means of aligning the Residual Heat Removal (RHR) System to the radwaste system, or manually switchover the HPCS suction valves to preclude an inadvertent ESF actuation. As a result of a previous event (LER 90-014), the procedure also included the caution that an automatic HPCS suction valve transfer could occur as early +3.0 inches due to instrument inaccuracy. The Plant Control Room Operator involved was aware of this procedural guidance. When Suppression Pool water volume reached approximately +3.0 inches indicated level, the automatic transfer occurred.

NR C Form 366A )669)

(649) Al'VISUVCO QMm I>U. elOVOlvm ExplREs: e/30/92 ATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EV REPORT (LER) I~RMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (P.530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO 1HE PAPERWORK REDUCTION PROJECT (31504)04). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

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

SEOUENTIAL NUMBER PN (ssre:

REVISION NUMSER Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 7 9 1 1 5 0 0 0 4 OF 0 6 TEXT /// mare e/seem /s rer)lr/red, Iree eddni'one////IC %%drm 366A'e/ (17)

B. Further Corrective Action

1. The Plant Control Room Operator involved was counselled on procedural requirements and performance expectations.

2. This LER will be included as a topic for discussion during the Licensed Operator Requalification Training Program.

Safet Si nificance There is no safety significance associated with this event. All systems operated as designed to cause a HPCS System pump suction valve switchover on the high Suppression Pool water level condition. In addition, there are no Suppression Pool high level restrictions during Operational Mode 4 (Cold Shutdown) because there is insufficient energy in the reactor during this condition to place significant loads on the containment. Furthermore, Plant Control Room Operators responded by lowering the Suppression Pool and realigning the system to pre-event status. Accordingly, this event posed no threat to the health and safety of either the public or Plant personnel.

Similar Events LER 90-014, "High Pressure Core Spray (HPCS) System Pump Suction Valve Switchover Actuation on High Suppression Pool Level due to Procedural Inadequacy."

EIIS Information EIIS Reference

~Sstem ~Com onent High Pressure Core Spray(HPCS) System BG HPCS-V-1 BG HPCS-V-15 BG Excess Flow Check (EFC) Valve Suppression Pool NH Condensate Storage Tank KA TK HPCS-P-1 BG HPCS-L IS-2A BG LIS NRC Ferro 366A 1669)

Af'PKvvED vrrlB Nv. 4lovs)iv>>

(64)9)

EXP IR ES: 4/30/92 ATEO BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EV REPORT HLER) I ORMATION COLLECTION REQUEST: 50JI 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 THE PAPERWORK REDUCTION PROJECT 13(500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON. OC 20503.

FACILITY NAME (1) DOCKET NUMBER (2I LER NUMBER (5) PAGE (3)

SEQUENTIAL REVISION YEAR NVMSER NUMBER Washin ton Nuclear Plant - Unit 2 0 5 0 0 0 3 7 9 1 015 0 0 0 5 oF0 TEXT /lfmore 4Oese /s ser)rrlred, vse eddioone/ NRC Form Si/64'4/ (17)

E I IS Information EIIS Reference

~Sstem ~Com onent HPCS-L IS-28 BG LIS Residual Heat Removal (RHR) System 80 RHR "A" Heat Exchanger 80 HX NRC Form 356A (669)

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