05000353/LER-1995-001, :on 950102,actuations of Unit 1 & Unit 2 Primary Containment & Rv Isolation Control Sys (PCRVICS) Occurred Due to End of Life Fuse Failure.Fuse Replaced & Insp of PCRVICS Circuitry Performed on 950125
| ML20080G167 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 01/30/1995 |
| From: | Boyce R, Kantner J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LER-95-001, LER-95-1, NUDOCS 9502060231 | |
| Download: ML20080G167 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(1) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2) |
| 3531995001R00 - NRC Website | |
text
Rob *rt W. Coyce Plant Manager Limenck Generatng se r e
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PECO ENERGY
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Limenck Genera 9ng Sur a PO Box 2300 Sanatoga, PA 19464 03N 215 3271M0 Ext 2030 10CFR 50.73 January 30, 1995 Docket Nos. 50-352 50-353 License Nos. NPF-39 NPF-85 U.S.
Nuclear Regulatory Commission Attn:
Document Control Desk Washington, DC 20555
SUBJECT:
Licensee Event Report Limerick Generating Station - Units 1 and 2 This LER reports actuations of the Unit 1 and Unit 2 Primary Containment and Reactor Vessel Isolation Control Systems (PCRVICS), Engineered Safety Features (ESF), and other ESFs, as a result of an end of life failure of a PCRVICS fuse coincident with the performance of a surveillance test procedure.
Reference:
Docket Nos. 50-352 50-353 Report Number:
2-95-001 Revision Number:
00 Event Date:
January 2, 1995 Report Date:
January 30, 1995 Facility:
Limerick Generating Station P.O.
Box 2300, Sanatoga, PA 19464-2300 This LER is being submitted pursuant to the requirements of 10CFR50.73(a)(2)(iv).
Very truly yours, a-3 k,
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DMS:cah cc:
T.
T.
Martin, Administrator Region I, USNRC N.
S.
Perry, USNRC Senior Resident Inspector, LGS a,
9502060231 950130
{DR ADOCK 05000353 PDR
,l 1
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED Bf 048 No. 3150 0104 I
(5-92)
EXPIRE 5 5/31/95 l
ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REOUEST: 50.0 HRS.
LICENSEE EVENT REPORT (LER)
FOPWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT ERANCH (MNBB 7714). U.S. NUCLEAR REGULATORY COMMIS510N.
(See reverse for required number of digits / characters for each block)
WASHINGTON. DC 20555-0001. AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104).
OFFICE OF MANMEMENT AND BUDGET. WASHINGTON DC 20503 F EILITY NAME (1)
DOCKti NUMBER (2)
FME (3)
Limerick Generating Station, Unit 2 05000 353 1 OF 5 IIILE (4) Actuations of the Unit I and Unit 2 PCRVICS (i.e., ESP), and other ESFs, as a result of an end of life fuse failure coincident with the performance of an ST procedure EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER F ACILITIES INVOLVED (8)
SEQUENTIAL REVISION FACILlif NAME 00CKE1 NUMBER MONTH DAY YEAR YEAR MONTH DAY YEAR 05000352 NUMBER NUMBER 1GS, Unit 1 F AClL1I Y NAMt DOCKET NUMBER 01 02 95 95
~~ 001 --
00 01 30 95 05000 OPERATING THIS REPORI IS SUBMITTED PURSUANT TO THE REOUIREMENTS OF 10 CFR $: (Check one or more) (11)
MCDE (9) 1 2J.402(b) 20.40b(c) x 50.73(a)(2)(iv) 73.71(D)
POWER 20.405(a)(1)(1) bO.36(c)(1) 50.73(a)(2)(v) 73.11(c)
LEVEL (10) 637.
20.405(a)(1)(11) 50.36(c)(2) 50.73(a)(2)(vii)
OTHER JU.405(a)(1)(iii) 50.73(a)(2)(1) 50.73(a)(2)(viii)(A)
(Specify in c
low Nt zu.405(a)(1)(iv) 50./3(a)(2)(ii) 50.73(as(2)(viii)(B) 20.4U5(a)(1)(v) 50.73(a)(2)(111) 50./3(a)(2)(x)LICENSEE CONTET FOR THIS LER (12)
NAME TELEPHONE NUMBER (incluce Area Code)
J. L. Kantner, Manager - Experience Assessment, LCS (610) 718-3400 COMPLETE ONE LlhE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
R 0 E
0
CAUSE
SYSTEM COMPONENT MANUFACTURER
CAUSE
SYSTEM COMPONENT MANUFACTURER D
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SUPPLEMENTAL REPORI EIFECTED (14)
EXPECTED MUNIH DAY YEAR YES SUBMISSION NO X
(if yes. complete EXPECTED SUBMISSION DATE).
DATE (15)
ASSIRAC1 (Limit to 14J0 spaces, i.e.
approximately 15 singie-spaced typewritten lines) (16)
On 01/02/95, during performance of a surveillance test (ST) procedure, an Instrumentation and Controls technician switched a radiation monitor to ' operate' which coincidentally caused fuse B21-F101A to blow.
This loss of power caused by the blown fuse resulted in automatic actuations of the Unit 1 and Unit 2 Primary Containment and Reactor Vessel Isolation Control Systems (PCRVICS), Engineered Safety Features (ESF), and other ESFs.
The fuse was replaced and all isolations were reset within 44 minutes.
The actual consequences of this event were minimal.
All affected systems responded as designed and there was no release of radioactive material to the environment as a result of this event.
The cause of the isolations was concluded to be an end of life fuse failure coincident with the performance of an ST procedure.
The PCRVICS circuitry was inspected and the ST procedure was performed again without incident.
No additional causes other than random equipment failure were identified, and therefore, no additional actions are planned.
._]
E FORM 356 (5 92)
.U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB h0. 3150 0104 (5-92)
EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION RE0 VEST: 50.0 HRS.
LICENSEE EVENT REPORT (LER)
NNFO N A, ECO AGE N BPAN TEXT CONTINUATION ggJ.s.,ggtE REgAlDR 90 g
REDUCTION FROJECT (3150-0104).
OFFICE OF MANAGEMENT AND BUDGET WASHINGTON. DC 20503.
F AClLlif NAME (1)
DOCKET NUMBER (2)
LER NUMBER (6)
PAGE (3)
SEQUENilAL Rivi510N YEAR "R
05000353 02 OF 05 Limerick Cencrating Station, Unit 2
~~ 001 00
~~
95 TExi (11 rnare space is requirec. use coastronal toples of NkC form 3tbA) (11)
Unit Conditions Prior to the Event:
Unit 1 was in Operational Condition (OPCON) 1 (Power Operation) at 63%
power level.
Ascension to 100% power level was being performed at the time of this event.
The
'A' train of the Standby Gas Treatment System (SGTS) was in service to inert the Unit 1 drywell with nitrogen.
A current limiter was installed on the
'A' SGTS flow dampers to control nitrogen flow into the Unit 1 drywell.
The normal Unit 1 Reactor Enclosure ventilation system was in service prior to and during this event.
Unit 2 was in OPCON 1 at 62% power level in end-of-cycle coastdown.
There were no Unit 2 structures, systems, or components out of service that contributed to this event.
Description of the Event:
On January 2, 1995, Instrumentation and Controls (I&C) technicians were performing Unit 2 Surveillance Test (ST) procedure ST-2-026-618-2, "NSSSS - Reactor Enclosure Ventilation Exhaust Duct Radiation -
High; Division IA, Channel A Functional Test."
At 1833 hours0.0212 days <br />0.509 hours <br />0.00303 weeks <br />6.974565e-4 months <br />, during performance of this ST procedure, an I&C technician switched the radiation monitor (i.e.,
RISH-026-2K609A) to ' operate' which coincidentally resulted in a blown fuse (EIIS:FU), B21-F101A, in the Auxiliary Equipment Room (AER) panel 10C622, " Inboard Valve Relays NSSSS Div 1."
The loss of power caused by the blown fuse resulted in automatic actuations of the Unit 2 Primary Containment and Reactor Vessel Isolation Control System (PCRVICS) (EIIS:JM), an Engineered Safety Feature (ESF), closing the outboard primary containment isolation valves in the following systems; Primary Containment Instrument Gas (PCIG) Process Lines (EIIS:LK), and Primary Containment Nitrogen Inerting Block Valves.
l NRC IORM 366A U.S. NUCLLAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150 0104 (5 92)
EXPIRES 5/31/95 ESTIMATED BUCEN IER RESPONSE TO COMPLY WITH THIS INFORMATI ' t OLLECTION REQUEST: 50.0 HRS.
LICENSEE EVENT REPORT (LER)
NNF0 r)th ANEC D
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B TEXT CONTINUATION (MNBB 7714). U.S NUCLEAR REGULATORY ComISSION.
WASHINGTON. DC 20555-0001. AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104).
OFFICE OF MANAGEMENT AND BUDGFT WASHINGTON. DC 20503.
l FACILITY NAME (1)
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LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL kiVlSlON 05000353 0 3 OF c5 Lilacrick Gene ra t ing St at ion, Unit 2
~~ 001 --
00 95 TEXT Ut more space Is required. use a00stronal copies of ML form 366A) (11) l The outboard isolation valves in the following Unit 2 PCRVICS subsystems received a signal to close, however, no valve movement occurred since the associated valves were already closed due to plant conditions prior to the event; o
Primary Containment Purge Supply and Exhaust, and o
Primary Containment Exhaust to Reactor Enclosure Equipment Compartment Exhaust (REECE).
I Additionally, the following Unit 2 ESF actuations occurred; o
Reactor Enclosure Ventilation (EIIS:VA) System isolated, e
'A' train of the Reactor Enclosure Recirculation System (RERS)
(EIIS:VA) initiated, and o
'A' train of the SGTS (EIIS:BH) received an initiation signal, and reconfigured to drawdown the Unit 2 Reactor Enclosure.
As a result of the flow limiter installed on the
'A' SGTS, the system was unable to drawdown and maintain the Unit 2 Reactor Enclosure Secondary Containment at the required differential pressure of negative 0.25 inches of water gauge during the time period of this event.
However, the requirements of Technical Specifications (TS) Section 3.6.5.1.1 were not violated.
Finally, as a result of the loss of power, the following Unit 1 PCRVICS systems and subsystems received a signal to isolate; Primary Containment Nitrogen Inerting Block Valves, and o
Primary Containment Purge Supply and Exhaust Valves.
o Isolation of these valves resulted in the termination of the activities being performed to inert the Unit 1 drywell.
This delay did not violate the requirements of TS Section 3.6.6.3.
At 1833 hours0.0212 days <br />0.509 hours <br />0.00303 weeks <br />6.974565e-4 months <br /> on January 2, 1995, licensed Main Control Room (MCR) operators observed annunciator indication in the MCR for isolations of the above listed PCRVICS valves.
Additionally, the I&C technicians immediately stopped performance of the ST procedure upon receipt of the unexpected annunciation.-
NRC f0Rf1 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150 0104 (5-92)
EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY W1TH THIS INFORMATION COLLECTION RE0 VEST: 50.0 HRS.
FORWARD COMMENTS REGARDING BURDEN ESTIMATE.TO LICENSEE EVENT REPORT (LER)
THE INFORMATION AND RECCRDS MANK;EMENT BRANCH TEXT CONTINUATION (MNBB 7714). U.S. NUCLEAR REGULATORY COMMISSION.
WASHINGTON. DC 20555-0001. AND TO THE PAPERWORK
{
REDUCTION PROJECT (3150-0104).
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YEAR SEQUENilAL RiW1510N
"#R "R
05000353 04 OF 05 Limerick Generating Station, Unit 2
~~ 001 -~
00 95 TEXT Ut inore space ss required, use acostsonal copses of hkC forrn 366A) (17)
MCR operators restored the PCIG system using PCRVICS isolation bypass switches in accordance with General Plant (GP) procedure GP-8,
" Primary 6nd Secondary Containment Isolation Verification and Reset,"
and the blown fuse was then replaced.
MCR operators then reset and restored the remaining isolations by 1917 hours0.0222 days <br />0.533 hours <br />0.00317 weeks <br />7.294185e-4 months <br /> on January 2,
- 1995, using Procedure GP-8.
All PCRVICS isolations previously mentioned above were reset, and normal system operations were restored within 44 minutes.
A four (4) hour notification was made to the NRC on January 2,
- 1995, at 2117 hours0.0245 days <br />0.588 hours <br />0.0035 weeks <br />8.055185e-4 months <br /> in accordance with the requirements of 10CFR 50.72(b)(2)(ii), since this event resulted in automatic actuations of ESFs.
Accordingly, this report is being submitted in accordance with the requirements of 10CFR50.73(a)(2)(iv).
Analysis of the Event
The consequences of this event were minimal.
There was no release of radioactive material to the environment as a result of this event.
The Unit 1 and Unit 2 PCRVICS isolation valves and system actuations functioned as designed under the loss of the system control logic power condition created by the blown power supply fuse.
The Unit 1 and Unit 2 isolations were bypassed or reset.
The affected systems were restored to their pre-transient conditions by operators in accordance with plant procedures within 44 minutes, thereby preventing any adverse impact on plant systems.
Immediate and follow-up actions to this type of event (i.e.,
loss of logic power) are provided in procedure GP-8.
Licensed operators receive requalification training to review and perform operator responses to transients of this type.
This training provides practice on immediate operator actions and minimizes the length of time certain systems are isolated reducing the adverse impact on the plant.
Therefore, as a result of adequate procedural guidance, training, and prompt operator actions, the event duration was limited and no adverse plant conditions developed.
NRC TOR'i 366A (5 92)
NRC f 0kM 366A U.S. NUCLEAR REGULATORY COMMIS510N APPROVED BY OMB NO. 3150 0104 (5 92)
EXPIRES 5/31/95 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REOUEST: 50.0 HRS.
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THE INFORMATION "O RECORDS MANMEMENT BRANCH (MNBB 7714), U.S.'duCLEAR REGULATORY COMMISSION TEXT CONTINUATION WASHINGTON, DC 20555-0001. AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104).
OFFICE OF MANMEMENT AND BUDGET. WASHINGTON. DC 20503.
FACILI1f NAME (1)
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YEAR SEQUENilAL Rivl510N NUMBER WR 05000 353 05 OF c5 Limerick Generating Station, Unit 2
-- 001 00 95 TLXI Ut snore space 15 required. use adastronal copies of MC f ann 366A) (11)
Additionally, if the fault introduced during the performance of the ST procedure had resulted in this logic system being inoperable, the redundant PCRVICS isolation logic channel would have been available to isolate the PCRVICS system if required.
The redundant trains of RERS and SGTS were unaffected by this event, and were available had an actual event requiring their operation occurred.
Cause of the Event
The cause of the isolations was the blowing of the PCRVICS fuse (i.e.,
B21-F101A), manufactured by Bussmann (Model No. Min 5).
The root cause of the event was concluded to be an end of life PCRVICS fuse failure coincident with the performance of the ST procedure.
Corrective Actions
1.
On January 25, 1995, an inspection of the PCRVICS circuitry and RISH-026-2K609A was performed to look for a possible short which would draw excessive current through fuse B21-F101A.
No additional causes other than random equipment failure of the fuse were identified.
2.
On January 25, 1995, procedure ST-2-026-618-2 was performed again, and was completed satisfactorily.
3.
Other plant activities ongoing at the time of the icolations were investigated to determine whether the blown fuse could have been caused by those activities; however, no cause could be identified.
Based on the above results and findings, we conclude that this event was caused by a random equipment failure, and therefore, no further corrective actions are planned.
R.revious Similar Occurrences:
Limerick Generating Station LER 1-89-059 reported the failure of the same fuse B21-F101A due to personnel error resulting from improper use of test equipment.
The corrective actions from this previous event would not have prevented this event from occurring.-