05000382/LER-2012-007, Regarding Inoperability of a Safety Related Valve Due to Backup Air Accumulator Leakage
| ML13002A231 | |
| Person / Time | |
|---|---|
| Site: | Waterford  (NPF-038) |
| Issue date: | 12/31/2012 |
| From: | Fugate C Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3F1-2012-0104 LER 12-007-00 | |
| Download: ML13002A231 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown |
| LER closed by | |
| IR 05000382/2013004 (20 November 2013) | |
| 3822012007R00 - NRC Website | |
text
W3F1-2012-0104 December 31, 2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk 11555 Rockville Pike Rockville, MD 20852
Subject:
Licensee Event Report (LER) 2012-007-00 Waterford Steam Electric Station, Unit 3 (Waterford 3)
Docket No. 50-382 License No. NPF-38
Dear Sir or Madam:
Entergy is hereby submitting Licensee Event Report (LER) 2012-007-00 for Waterford Steam Electric Station, Unit 3 (Waterford 3). This report provides details associated with inoperability of a safety related valve due to backup air accumulator leakage.
Based on plant evaluation, it was determined that this condition is reportable under 10 CFR 50.73(a)(2)(i)(B), 10 CFR 50.73(a)(2)(ii)(B), and 10 CFR 50.73(a)(2)(v)(D).
This report contains no new commitments. Please contact Chester Fugate, Licensing Manager, at (504) 739-6685 if you have questions regarding this information.
Sincerely, CF/WH
Attachment:
Licensee Event Report 2012-007-00 Entergy Operations, Inc.
17265 River Road Killona, LA 70057-3093 Tel 504-739-6685 Fax 504-739-6678 cfugate@entergy.com Chester Fugate Licensing Manager Waterford 3
W3F1-2012-0104 Page 2 cc:
Mr. Elmo E. Collins, Jr., Regional Administrator U.S. NRC, Region IV RidsRgn4MailCenter@nrc.gov NRC Project Manager for Waterford 3 Kaly.Kalyanam@nrc.gov NRC Senior Resident Inspector for Waterford 3 Marlone.Davis@nrc.gov
Attachment to W3F1-2012-0104 Licensee Event Report 2012-007-00
NRC FORM 366 (10-2010)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of digits/characters for each block)
APPROVED BY OMB NO. 3150-0104 EXPIRES 10/31/2013
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Waterford 3 Steam Electric Station 05000 382 1 OF 4
- 4. TITLE Inoperability Of A Safety Related Valve Due To Backup Air Accumulator Leakage
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO MONTH DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 10 31 2012 2012 - 007 - 00 12 31 2012 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B)
DEFUELED 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C) 0 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
OTHER Specify in Abstract below or in energized ASCO NP8344 solenoid valves listed in the Extent of Condition. Once complete, determine if the solenoid valve PM frequency needs to be adjusted for PM optimization.
Enhancement: Add instructions to the next ASCO NP8344 replacement PM to retain the removed solenoid valve and provide to the AOV Engineer for forensic analysis.
SAFETY SIGNIFICANCE
The limiting event is a design basis tornado strike which damages the two non-missile protected DCT cells, causing CCW leakage. Lowering level in the CCW Surge Tank is indicative of a leak in the system, which is assumed for the design basis tornado event. During the tornado event, a Loss of Offsite Power (LOOP) and failure of a single Emergency Diesel Generator (EDG) is assumed. On the operable train, the unprotected portions of the DCT are assumed damaged (up to 40%) by a missile strike, causing system leakage. A LO-LO level signal from the CCW Surge Tank will automatically close isolation valve CC-135B and open bypass valve CC-134B. Operators will then isolate the damaged DCT cells and place the operable DCT cells back into service within two hours. With the loss of IA, a backup IA accumulator is credited for operation of valves CC-134B and CC-135B to restore the DCT back to service in order to cool the plant auxiliary heat loads and eventually the shutdown cooling heat load. The accumulator is supplied directly from instrument air and has no backup after the accumulator air supply is depleted.
Plant operators will be alerted to the isolated DCT through Control Room annunciators such as CCW SURGE TANK LEVEL LO-LO and DRY COOLING TOWER ISOLATED. Plant off-normal procedures address DCT leakage and recovery. If operators are unable to operate CC-134B or CC-135B because of accumulator leakage, plant emergency operating procedures provide direction for restoration of IA to restore operation to CC-134B and CC-135B. Although IA is a non-safety related system, the IA compressors and controls are powered from the assumed running EDG during which an alternate IA compressor cooling source is provided.
While the DCT is isolated and bypassed, the Auxiliary Component Cooling Water (ACCW) [CCW] system with Wet Cooling Towers (WCT) is the cooling source for the CCW Heat Exchangers and remains available, but at reduced capacity because the same tornado strike is assumed to damage the associated WCT fans.
The Waterford 3 Final Updated Safety Analysis Report (UFSAR) documents the probability of a tornado striking the plant site within the Protected Area as approximately 6.3 E-4 per year or about once every 1585 years.
Engineering calculations were performed using the NRC approved TORMIS methodology. These calculations determined that the probability of a tornado strike in a DCT location and damaging unprotected DCT cells is 6.8 E-7 per year.
The low probability of a tornado strike which damages unprotected DCT cells combined with the proceduralized actions for restoration of IA demonstrates that there is minimal impact to nuclear and radiological safety.
SIMILAR EVENTS
Corrective action program data for the past three years was searched for similar failures. No similar failures were found.
ADDITIONAL INFORMATION
Energy industry identification system (EIIS) codes are identified in the text within brackets [ ].