05000219/LER-2001-001, Re Reactor Shutdown Completion Required by Technical Specifications
| ML020320036 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 01/07/2002 |
| From: | Degregorio R AmerGen Energy Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2130-01-20264 LER 01-001-00 | |
| Download: ML020320036 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv), System Actuation |
| 2192001001R00 - NRC Website | |
text
AmerGen.
AmerGen Energy Company, LLC Oyster Creek US Route 9 South PO. Box 388 Forked River, NJ o8731-0388 An Exelon/British Energy Company 10 CFR 50.73(a)(2)(i)
January 7, 2002 2130-01-20264 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington DC 20555
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219-Licensee Event Report 01-001 Reactor Shutdown Completion Required by Technical Specifications Enclosed is Licensee Event Report LER 01-001. This event did not affect the health and safety of the public.
If any additional information or assistance is required, please contact Mr. John Rogers of my staff at 609.971.4893.
Very truly yours, Ron J. DeGregrw Vice President, Oyster Creek RJD/JJR
- - cc:
Administrator, Region I NRC Project Manager lz NRC Senior Resident Inspector 0
It \\
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (4-95)
APPROVED BY OMB NO. 3150-0104 EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY.
FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RMATION AND RECORDS MANAGEMENT BRANCH (T-6 F33), U.S. NUCLEAR LICENSEE EVENT REPORT (LER)
REULATORY COMMISSION, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.
FACILITY NAME (1)
DOCKET NUMBER (2)
]
PAGE (3)
Oyster Creek Unit 1 05000 -219 1 of4 Completion of Reactor Shutdown Required by Technical Specifications EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
MONTH DAY YEAR l YEAR SEQUENTIAL REVISION MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NUMBER 50 I 1 12 01 01 01 00 lFACILITY NAME DOCKETNUMBER 05000 OPERATING l N ] THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 6: (Check one or more) (11) l J 120.2201(b) 20.2203(a)(2)(v)
X 50.73(a)(2)(i) 50.73(a)(2)(viii)
POWER 1100 ]_
20.2203(a)(1) 20.2203(a)(3)(i) 50.73(a)(2)(ii) 50.73(a)(2)(x)
I 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)(ii) 50.36(c)(2) l O.73(a)(2)(v)
L 1LICENSEE CONTACT FOR THIS LER (12) lNAME L
TEEHNE NUMBER (Include Area Code)
John Rogers
{
609.971.4893 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE
SYSTEM I
COMPONENT MANUFACTURER REPORTABLE
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE TO EPIX TO NPRDS B
SUPPLEMENTAL REPORT EXPECTED (14)
EXPECTED MONTH DAY YEAR l(If yes, complete EXPECTED SUBMISSION DATE).
lXi°l ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
On November 11, 2001, a 4160 VAC cable failure de-energized the 1B2 Unit Substation of the 480 VAC system. Due to the equipment which was declared inoperable, it was determined that a reactor shutdown would be required. On November 12, 2001, at 3:33 am, the reactor was placed in the COLD SHUTDOWN CONDITION.
The cause of the cable failure was determined to be a localized insulation weakness aggravated by water intrusion into the cable conduit.
The safety significance of this occurrence was determined to be minimal. Although the 1B2 Unit Substation of the 480 VAC system was lost, the redundant electrical division remained fully operable at all times. At no time during this event did a functional failure of any safety system occur. The plant remained within Technical Specifications limits at all times, and achieved a COLD SHUDOWN CONDITION within the allowed time limits.
The failed portion of the cable was replaced, the plant was restarted and resumed POWER OPERATION. Long term actions include evaluating a new design cable and possible rerouting of the cable run.
NRC FORM 366 (4-95)U.S. NUCLEAR REGULATORY COMMISSION (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6)
PAGE (3) 05000 NUMBER Oyster Creek, Unit 1
- - 219 01 01 00 2
of 4
TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
DATE OF OCCURRENCE The condition described in this report occurred on November 12, 2001.
IDENTIFICATION OF OCCURRENCE A 4160 VAC cable failure on November 11, 2001, de-energized the 1 B2 Unit Substation of the 480 VAC system. This resulted in the requirement to isolate the Reactor Building Closed Cooling Water System containment penetrations. POWER OPERATION cannot continue with these valves closed. A normal reactor shutdown was commenced which was completed when the reactor was placed in the COLD SHUTDOWN CONDITION on November 12, 2001.
CONDITIONS PRIOR TO DISCOVERY The plant was operating at approximately 100% power, with all reactor plant pressures and temperatures normal for full power operations.
DESCRIPTION OF OCCURRENCE On Sunday, November 11, 2001, at 06:10 AM, power was lost to the 1B2 Unit Substation of the 480 VAC system (EIIS - EC). It was determined that the loss of 480VAC power was the supply breaker (EIIC - 52) from the 4160 VAC system (EIIS - EA) tripping open due to a ground fault.
The 1B2 Unit Substation was declared inoperable. The loss of power to containment penetration isolation valves for the Reactor Building Closed Cooling Water System (EIIS - CC) rendered the isolation valves inoperable. Therefore, this inoperability required the isolation of the Reactor Building Closed Cooling Water System penetrations. POWER OPERATION can not continue with these penetrations isolated. At 6:10 AM, a four hour Technical Specification Limiting Condition for Operation was entered to allow for diagnostic evaluation.
Since power could not be restored in the four hour time frame allowing the penetration to remain open, at 9:36 AM a normal reactor shutdown was commenced, to be completed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in accordance with Technical Specification 3.5.A.3.a.(2). It was subsequently determined that the ground fault was due to a faulted cable (EIIC - LAR) in an underground conduit (EIIC - CND) between the iD 4160 VAC bus (EIIC - PL) and the 4160/480 VAC stepdown transformer (XFMR) at the 1 B2 480VAC unit substation.U.S. NUCLEAR REGULATORY COMMISSION 1(4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6)
PAGE (3) 05()0 lYEAR I SENQUENTIAL I REV) 05000 NUMBER Rv OysterCreek, Unit
- - 219 [01 -
01 00 3
of 4
TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
DESCRIPTION OF OCCURRENCE (Cont.)
Additionally, the following trains in Safety Related Systems were declared inoperable: Standby Gas Treatment System 2; 480 VAC Substation 1B2 and Vital Motor Control Center 1B2; B 125 VDC Bus; Containment Spray System 2; B Hydrogen Monitor; A Isolation Condenser (due to no operable DC isolation valves); and Torus Wide Range Level Indicator.
During the normal reactor shutdown, on November 11, 2001, the voltage on the B 125 VDC bus decreased to the point that motor operated valve (EIIC - 20) operability and DC control power (EIIS - EJ) to the plant approached operational limits. At 3:03 PM, a manual reactor scram was inserted, placing the plant in a SHUTDOWN CONDITION. At 10:05 PM, the cross tie between the A and B 480 VAC systems was closed, restoring power to the 1 B2 Unit Substation loads, except for the B 125 VDC Battery Charger. The 1 B2 480 VAC loads became fully functional, but remained inoperable due to the abnormal power supply. The normal reactor shutdown continued.
The B 125 VDC Battery Charger was re-energized at 11:17 PM.
The shutdown was completed when the reactor was placed in the COLD SHUTDOWN CONDITION on Monday November 12, 2001, at 3:33 AM. At no time during this occurrence did any safety system functional failure occur.
FAILURE DATA Cable - Anaconda Unishield; 5KV rated.
APPARENT CAUSE The reactor shutdown was completed to satisfy the Technical Specification requirements for equipment declared inoperable due to the loss of power to the 1 B2 Unit Substation in the 480 VAC system. The cause of the loss of power was a faulted 4160 VAC cable supplying the 1 B2 Unit Substation. The faulted cable was removed and analyzed. It was determined that a localized weakness of the insulation due to delamination of the jacket caused the cable to fail. This weakness was aggravated by water intrusion into the underground conduit containing the cable, subsequent cable drying, and corona degradation of the insulation.U.S. NUCLEAR REGULATORY COMI (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6)
PAGI l 0500 lYEAR SENQUENTIA I REV 05000 NER UMBER Oyster Creek, Unit 1
- - 219 01 01 00 4
o TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
ANALYSIS OF OCCURRENCE AND SAFETY ASSESSMENT The safety significance of this occurrence was minimal. Although the 1 B2 Unit Substation of the 480 VAC system was lost, the redundant electrical division remained fully operable at all times. At no time during this event did any functional failure of a safety system occur. The plant remained within Technical Specifications limits at all times, and achieved a COLD SHUDOWN CONDITION within the allowed time limits. There was no radioactive release, nor was there any effect on the health and safety of the public.
CORRECTIVE ACTIONS
Immediate Corrective Actions Immediately upon the completion of the reactor shutdown, the Maintenance organization began cable replacement activities, while the Engineering organization commenced the root cause analysis.
The cause of the cable failure was determined to be a localized weakness in the cable which was aggravated by the presence of moisture intrusion. The cable was replaced with a Cablec cable.
Cables similar to the one that failed were tested. No additional concerns were noted.
After appropriate repairs and replacements were made, the 480 VAC system was restored to the normal split plant lineup on November 17, 2001. The loads which had been declared inoperable due to the cable failure were restored to full operability. The reactor plant was restarted on November 18, 2001, and commenced providing power to the grid on November 19, 2001.
Long Term Actions New style cables are being evaluated which could take advantage of modern manufacturing and extrusion processes and potentially be used to replace the existing cables. Additionally, the possibility of re-routing the cables using above ground cable trays is being considered.
WMISSION