05000219/LER-2002-003, Re Insufficient Appendix R Separation Criteria Due to Sand Erosion
| ML023600009 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 12/06/2002 |
| From: | Degregorio R AmerGen Energy Co, British Energy Co, Exelon Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 2130-02-20335 LER 02-003-00 | |
| Download: ML023600009 (6) | |
| 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) |
| 2192002003R00 - NRC Website | |
text
AmerGen SM AmerGen Energy Company, LLC Oyster Creek US Route 9 South PO Box 388 Forked River, NJ 08731-0388 An Exelon/British Energy Company 10 CFR 50.73(a)(2)(i)
December 6, 2002 2130-02-20335 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington DC 20555
Dear Sir:
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219 Licensee Event Report 02-003; Insufficient Appendix R Separation Criteria due to Sand Erosion Enclosed is Licensee Event Report LER 02-003. 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. DeGregorio Vice President, Oyster Creek RJD/JJR cc:
Administrator, Region I NRC Project Manager Senior Resident Inspector S
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.' -1NrvcFORM 366
'1(4-95)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES J4/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST 500 HRS REPORTED LESSONS LEARNED ARE INCORPORATED INTO THE IUCENSING PROCESS AND FED BACK TO INDUSTRY IORWARD COMNMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (T-6 F33), U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON.
DC 20555-0001.
AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OMCE or MANAGEMENT AND BUDGET, WASHINGTON. DC 20503 LICENSEE EVENT REPORT (LER)
FACILITY NAME (1)
DOCKET NUMBER (2)
PAGE (3)
Oyster Creek Unit 1
]
05000 - 219 1 of 4 TITLE (4)
Insufficient Appendix R Electrical Separation due to Sand Erosion EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
MONTH DAY YEAR YEAR SEQUENTIAL REVSION MONTH DAY YEAR FACiLITY NAME DOCKET NUMBER NUMBER NUMBER 0
1O TM 10 10 02 02 03
-- N00 12 06 FACILITY NAME DOCKT NUMBR 05000 OPERATING N
THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 3: (Check one or more) (11)
MODE (9) 1 20 2201(b) 20 2203(aX2)(v) 50 73(a)(2X0) 50.73(a)(2)(viii)
POWER 101 _
20 2203(a)(1) 20 2203(aX3)(i)
X 50 73(a)(2Xii) 50 73(a)(2)(x)
LEVEL (10) j 20 2203(a)(2)(i) 20 2203(aX3)(ni) 50 73(a)(2XII1) 73 71 20 2203(a)(2Xii) 20 2203(aX4) 50 73(a)(2)(iv)
OTHER I
20 2203(a)(2Xiii) 50 36(cX 1) l 150 73(a)(2Xv) l-20 2203(a)(2Xiv) 150 36(cX2) l50 73(a)(2Xviu)
LICENSEE CONTACT FOR TlHS LER (12)
NAME TELPHONE NUMBER (inlde Area Code)
COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE
- - a l
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE TO NPRDS
,~,TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14)
EXPECTED
{ MONTH DAY YEAR l
(fyes, complete EXPECED SUBMISSION DATE) 33 ABSTRACT (Luot to 1400 spaces, i.e, approximately 15 single-spaced typewritten lines) (16)
While performing a cable pulling evolution, it was noticed that a void had been created beneath a portion of the two 480 VAC switchgear rooms. This void created an open area that had not previously existed between two 4160 VAC feeder conduits. Because of the void, Appendix R electrical separation criteria were no longer met. Apparently, sand had settled and/or eroded away over time, thus opening this void beneath the A and B 480 VAC switchgear rooms.
The safety significance of this discovery is minimal as there is no combustible material in the void.
Both cables are contained in conduit and have sufficient Class 1E electrical separation.
Immediately upon discovery, a continuous fire watch was stationed. Additional actions were subsequently taken to open communication between the void and adjacent area smoke detectors.
This would provide early warning of a degrading condition. Long term corrective actions are being evaluated. A long term solution will be finalized and a supplemental LER will be submitted by September 30, 2003.
- - t r~nUS. NUCLEAR REGULATORY COWiN (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET (2)
LER NUMBER (6)
PAGI 05000 Y
SEQUENTIAL REV Oyster Creek, Unit 1
- - 219 02 03 00 2o TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
DATE OF DISCOVERY This event was discovered on October 10, 2002, at 5:59 PM.
IDENTIFICATION OF OCCURRENCE While performing a cable pulling evolution, it was noticed that a void had formed beneath a portion of the two 480 VAC switchgear rooms. This void created an open area that had not previously existed between two 4160 VAC feeder conduits to Unit Sub Stations (USS) 1A2 and 1B2. This discovery was considered reportable under 10 CFR 50.73(a)(2)(ii).
CONDITIONS PRIOR TO DISCOVERY At the time of discovery, the plant was in cold shutdown for refueling. However, it is not known when the void was formed and it has been concluded that it existed during all modes of plant operation.
DESCRIPTION OF OCCURRENCE During replacement of the 4160 VAC feeder cable to transformers in the 480 VAC A switchgear room, it was discovered that an opening existed around the conduit that penetrated the floor. This opening had previously been sealed with M-board and Kaowool and had been broken during the cable replacement project. Upon examination to determine a repair for the floor seal, an open underground void was discovered (approximately four feet deep, three feet wide, and 50 feet long) in the area between the Reactor and Turbine Building walls. This void affected the Appendix R fire separation of the 4160 VAC feeder cables. With this area open, the 4160 VAC feeder cables to USS 1A2 and USS 1B2 were not sufficiently separated from each other under the floor area.
These cables were routed in separate conduits, and the conduits were separated horizontally by approximately ten feet. Without the sand in place, the separation of these redundant cables failed to meet Appendix R Section lI.G.2 requirements (provide a three hour fire barrier; or provide a one hour barrier with automatic suppression and detection; or provide 20 ft separation with no intervening combustibles with automatic suppression and detection).
As the cables are both enclosed in rigid steel conduit, they do meet class 1E electrical separation criteria as required by Installation Specification SP-9000-41-005.
I1SSIONUS. NUCLEAR REGULATORY COMMISSION (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
]DOCKLE (2)
LER NUMBER (6)
PAGE (3) 05000 YEAR SE Rl REV OysterCreek, Unit 1
- - 219 02 03 00 3
of 4
TEXT (If more space is required, use additonal copies of NRC Form 366A) (17)
APPARENT CAUSE The apparent cause of this discovery is that sand had settled and/or eroded away over time, thus opening this void beneath the A and B 480 VC switchgear room floors.
ANALYSIS OF OCCURRENCE AND SAFETY ASSESSMENT This discovery has minimal safety significance for Appendix R scenarios. The only combustible material within the void is in the cables in the conduits. A fire in either conduit would not propagate to the other conduit. Additionally, the rooms where the conduits terminate have detection systems which would alert operators to any fire. The most likely source of fire exposure to these cables is from the 480v room(s) directly above the void. These rooms are provided with automatic fire suppression and detection, making it unlikely that a fire of sufficient magnitude would develop capable of affecting the cables. Any combustible attempting to enter the void would have to originate from an area which also has detection capability, again alerting operators to the fire.
This discovery has no impact on the safety significance for non-Appendix R scenarios. This discovery does not affect the Class lE operability of the 4160V feeder cables to USS 1A2 &1B2 as the Class IE separation criteria is maintained and would be fully operable during a non-Appendix R scenario.
CORRECTIVE ACTIONS
Immediate Corrective Actions
- 1. A continuous fire watch was stationed.
- 2. A rated fire seal was installed at the floor penetration of both A and B transformers where feeder cables enter, to prevent a fire in either 480 VAC room from propagating into the void area.
- 3. Holes were drilled in hallway floor plate above the void to allow any potential smoke to communicate with hallway area smoke detectors.
- 4. Potential Seismic issues were reviewed and found not to be an issue.
- 5. Extent review was performed for possible other cases where below grade conduits are required to be covered for Appendix R separation criteria, no other concerns were discovered.
U.s. INUCLI*AK K1AiULA1UKY CUMMIb1UN NRIC FORI 366A (4-95)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR KE(iULATOU1Y CNNDUCTION FACILITY NAME (1)
Oyster Creek, Unit 1 TEXM (If more space is required, use additional copies of NRC Form 366A) (17)
CORRECTIVE ACTIONS (cont.)
Short term corrective actions.
- 1. A Supporting Operability Documentation review was completed prior to plant start-up from the IR19 refueling outage.
- 2. The Fire Brigade received additional instructions on this discovery. The Fire Brigade Pre-Fire Information Plan was updated for a fire in this area.
- 3. Tools, additional fire extinguishers, and a cellar nozzle were stationed for use in the unlikely event of a fire in the void area Long term corrective actions A permanent solution will be finalized and a supplemental LER will be submitted documenting the conclusions by September 30, 2003.
SIMILAR EVENTS
None.
Oyster Creek Licensing Correspondence Distribution Sheet File No.
02083 Reference/Letter No.
2130-02-20335 Letter Date Date Sent / Received 12/06/2002 12/06/2002 Title Description: LER 02-003; Insufficient Appendix R Separation Criteria LICENSING ENGINEER: John Rogers SPECIAL NOTES:
Office of the President R. J. DeGregorio (Letter Only)
R. Maldondo Communications Engineerinn V.Aggarwal M. Newcomer A. Agarwal D. Barnes T. E. Quintenz M. Button F. Buckley T. Powell R. Larzo C. Lefler AmerGen/Exelon C. Pardee G. Vanderheyden M. Gallagher (Outgoing Only)
J. Hufnagel (Outgoing Only)
D. Walker KS Document Ctr w/ attachment I Toncic D Distel Jeff Benjamin OCAB2 OCAB2 OCAB2 OCAB3 OCAB3 OCAB3 OCAB3 OCAB3 OCAB3 OCAB3 OCAB3 OCAB3 OCAB3 KSA 3-N KSA 3-N KSA 3-E KSA 3-E KSA 3-E KSA 1-N KSB 3-W KSA 3-E Cantera X
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Oyster Creek E. Harkness C Wilson J Freeman J. Vacaro S Bailey J..Bobba A. Krukowski R. Ewart G. True D. Norton W. Collier D. McMillan J. Magee M. Massaro R Adams M. Moore MOB MOB MOB MOB AOB AOB NMB OCAB2 Whse 2 Whse 1 AOB Aux Bldg 12 NMB OCAB2 OCAB2 AOB X
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X Other NSRB (22 copies)
T Trettel M Carlson X
OCAB3 X
OCAB3 X
External Distribution NJBNE - K. Tosch INPO ANI - R. Oliveira BPU - R. Chilton T. Gould GE - P. Ray X
File Index Number: 20.16.01.01 w/attachment Cross Reference Number: 20.16.01.01 w/attachment