05000298/LER-2014-001, Regarding Secondary Containment Declared Inoperable Due to Rise in Differential Pressure
| ML14070A363 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 03/06/2014 |
| From: | Limpias O Nebraska Public Power District (NPPD) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NLS2014013 LER 14-001-00 | |
| Download: ML14070A363 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(ii)(B), Unanalyzed Condition 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 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2982014001R00 - NRC Website | |
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N Nebraska Public Power District Always there when you need us NLS2014013 March 6, 2014 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001
Subject:
Licensee Event Report No. 2014-001-00 Cooper Nuclear Station, Docket No. 50-298, DPR-46
Dear Sir or Madam:
The purpose of this correspondence is to forward Licensee Event Report 2014-001-00.
There are no new commitments contained in this letter.
Sincerely, Oscar A. Li pias Vice President Nuclear-Chief Nuclear Officer hJo Attachment: Licensee Event Report 2014-001-00 cc:
Regional Administrator w/attachment USNRC - Region IV Cooper Project Manager w/attachment USNRC - NRR Project Directorate IV-l Senior Resident Inspector w/attachment USNRC - CNS SRAB Administrator w/attachment NPG Distribution w/attachment INPO Records Center w/attachment via ICES entry SORC Chairman w/attachment CNS Records w/attachment COOPER NUCLEAR STATION P.O. Box 98 / Brownville, NE 68321-0098 Telephone: (402) 825-3811 / Fax: (402) 825-5211 www.nppd.com
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01131/2017 01-2014)
Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.
Reported lessons learned are incorporated into the licensing process and fed back to industry.
l LICENSEE EVENT REPORT Send comments regarding burden estimate to the FOIA, Privacy and Information Collections (LER)
Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and (See Page 2 for required number of Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC digits/characters for each block) 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
. PAGE Cooper Nuclear Station 05000298 1 OF4
- 4. TITLE Secondary Containment Declared Inoperable due to Rise in Differential Pressure
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER NUMBER NO.
MONT DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 01 06 2014 2014
- - 001
- - 00 03 06 2014 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMrrrED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
- 10. POWER LEVEL El 20.2203(a)(1)
El 20.2203(a)(4)
[] 50.73(a)(2)(ii)(B)
[] 50.73(a)(2)(viii)(B)
[] 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
E] 50.73(a)(2)(iii)
[I 50.73(a)(2)(ix)(A) 1C 20.2203(a)(2)(ii)
[] 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
[I 50.73(a)(2)(x) 1] 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
[E 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5)
El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
ED 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B) 0 50.73(a)(2)(v)(D)
Specify in Abstract below or in As a result of opening the wrong valve, the exhaust fan discharge damper of the RRMG that was operating closed. The NLO felt the change in DP and closed the drain valve, which opened the exhaust fan discharge damper of the RRMG, thus restoring ventilation. DP remained negative at all times. The NLO then checked the tag and realized he was on the wrong component.
Secondary containment DP was restored to within TS limits and was declared operable at 03:02 and LCO 3.6.4.1, Condition A, was exited.
Investigation of the event revealed that guidance documents did not contain information about the effects of cross-over leakage between the RRMG HVAC exhaust system and the reactor building envelope. No documented information was available that would have indicated that inadvertent operation of any valve in the RRMG HVAC exhaust ventilation room could cause a TS violation of secondary containment. The error of the NLO revealed that cross-over leakage between the reactor building envelope and the RRMG HVAC exhaust system existed such that the operation of one affects the other.
A Human Performance Error Review Board was conducted with the NLO. Several human error trap factors were identified which included poor-lighting conditions, danger tagged scaffolding, high noise, and that the individual was a newly qualified NLO. Also contributing to the error were loss of focus and lack of thorough verification of components to be manipulated.
Immediate actions included a stand down to review the event with operations personnel. For five weeks following the event, actions for the operator to call supervision or the job lead for verification was applied, and shiftly observations for qualified NLOs were implemented.
BASIS FOR REPORT This event is reportable as a loss of safety function under 10 CFR 50.73(a)(2)(v)(C and D) - An event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material or mitigate the consequences of an accident.
Event Notification 49694 was made to the Nuclear Regulatory Commission.
Secondary containment was declared inoperable due to failure to meet TS SR 3.6.4.1.1. An engineering analysis was performed and the results demonstrate that secondary containment integrity, isolation capability, and standby gas treatment capability to maintain secondary containment vacuum were not lost during the event. As such, this event will not be counted as a Safety System Functional Failure for the Nuclear Regulatory Commission performance indicator since no loss of safety function occurred.
SAFETY SIGNIFICANCE
No equipment was damaged, no one was hurt, and the safety of the public was not at risk. While the DP did rise above the TS limit of -0.25 inches of water column during the event, to -0.21 inches of water column, the reactor building envelope still maintained a negative DP throughout the two minute event period. During that two minute period, primary containment was intact and fully operable, no fuel was moved, shifted or transported, no unmonitored radiological release occurred, and all other safety systems were fully functional.
CAUSE
CNS determined the root cause to be that the organization was not fully aware of the effects of the inter-relationship (cross-over leakage) between the reactor building envelope and the RRMG HVAC exhaust system since it was not captured in applicable plant documents (procedures and training), which affected the ability to identify the potential to impact secondary containment DP.
CORRECTIVE ACTION
To prevent recurrence, CNS will:
Revise RRMG operational procedures to ensure that adequate precautions are taken to avoid exceeding the -0.25 inches of water column DP requirement if RRMG HVAC is to be secured while secondary containment requirements have to be maintained.
Incorporate information about the effects of cross-over leakage between the reactor building envelope and the RRMG HVAC exhaust system into the appropriate operator training materials.
Develop and establish a surveillance procedure to directly measure air leakage from the reactor building envelope into the RRMG HVAC exhaust system. The results shall be used to update the RRMG HVAC exhaust leakage numbers in the appropriate procedure used to estimate cross-over air leakage for radiological effluent calculations.
PREVIOUS EVENTS On September 10, 2012, secondary containment was breached due to both airlock doors in the reactor building being inadvertently left open simultaneously. This was reported under LER 2012-003-00 as a loss of safety function under 10 CFR 50.73(a)(2)(v)(C and D) - An event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to control the release of radioactive material or mitigate the consequences of an accident.