05000458/LER-2016-006, Potential Loss of Safety Function of Multiple Systems Due to Design Deficiency in 480-volt Circuit Breakers
| ML16208A056 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 07/12/2016 |
| From: | Maguire W Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RBF1-16-0081, RBG-47690 LER 16-006-00 | |
| Download: ML16208A056 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 4582016006R00 - NRC Website | |
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RBG-47690 July 12, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
Subject:
RBF1-16-0081 Licensee Event Report 50-458 I 2016-006-00 River Bend Station - Unit 1 Docket No. 50-458 License No. NPF-47
Dear Sir or Madam:
Entergy Operations, Inc.
River Bend Station 5485 U.S. Highway 61 N St. Francisville, LA 70775 Tel 225-381-4157 William F. Maguire Site Vice President In accordance with 10 CFR 50.73, enclosed is the subject Licensee Event Report. This document contains no commitments. If you have any questions, please contact Ms. Kristi Huffstatler at 225-378-3305.
Sincerely, WFM/dhw Enclosure cc:
U. S. Nuclear Regulatory Commission Region IV 1600 East Lamar Blvd.
Arlington, TX 76011-4511 NRC Sr. Resident Inspector P. 0. Box 1050 St. Francisville, LA 70775 INPO (via ICES reportirig)
Licensee Event Report 50-458 I 2016-006-00 July 12, 2016 RBG-47690 Page 2 of 2 Central Records Clerk Public Utility Commission of Texas 1701 N. Congress Ave.
Austin, TX 78711-3326 Department of Environmental Quality Office of Envirgnmental Compliance Radiological Emergency Planning and Response Section Ji Young Wiley P.O. Box 4312 Baton Rouge, LA 70821-4312
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06-2016)
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 />.
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Reported lessons learned are incorpbrated into the licensing process and fed back to industry.
+
LICENSEE EVENT REPORT (LER)
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail (See Page 2 for required number of digits/characters for each block) to lnfocollects.Resourte@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a (See NUREG-1022, R.3 for instruction and guidance for completing this form means used to impose an information collection does not display a currently valid OMB control htl!l ://www. nrc.ggv/reaging-rm/doc-colle!;!ions/nuregs/sjaff/sr1 022/r3l) number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE River Bend Station - Unit 1 05000 458 1 OF 3
- 4. TITLE Potential Loss of Safety Function of Multiple Systems Due to Design Deficiency in 480-volt Circuit Breakers
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
SEQUENTIAL I REV FACILl1Y NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR 05000 FACILl1Y NAME DOCKET NUMBER 05 13 2016 2016 -
006 - 00 07 12 2016 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
D 20.2201 (b)
D 20.2203(a)(3)(i)
D 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A) 1 D 20.2201 (d)
D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.22os(a)(1>
D 20.2203(a)(4>
D so.73(a)(2)(m>
D 50.73(a)(2)(ix)(A)
D 20.22os(a)(2)(i)
D 50.36(c)(1)(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.22os(a)(2)(ii)
D 50.36(c)(1)(ii)(A)
D 50.73(a)(2)(v)(A)
D 73.71(a)(4)
D 20.2203(a)(2)(m>
D so.36(c)(2>
D 50.73(a)(2)(v)(B)
D 13.11(a)(s)
D 20.2203(a)(2)(iv)
D so.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 1s.11(a)(1>
100 D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
[{] 50.73(a)(2)(v)(D)
D 1s.11(a)(2)(i>
D 20.2203(a)(2)(vi)
[{) 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 13.77(a)(2)(ii)
'.~::it;,::"£l:ll D 50.73(a)(2)(i)(C)
D OTHER Specffy in Abstract below or in Given this specific set of circumstances, breakers in the closed position are not susceptible to this failure mod~. For equipment that can be run continuously, the compensatory measure is to maintain the affected breakers in the closed position. For the breakers in the HVC system, the compensatory measure is to clear the condition and restart the system.
These measures ensured the continued operability of the affected breakers.
CORRECTIVE ACTIONS TO PREVENT RECURRENCE The Masterpact breakers serving the air handling units in the main control building air conditioning system, the standby gas treatment system filter trains, and the emergency exhaust fans in the diesel generator rooms have been modified to correct the reported deficiency. The remaining breakers in the affected population are being scheduled for modification.
PAST OCCURRENCE EVALUATION Design deficiencies in Masterpact breakers were previously reported in LER 050-458 I LER 2016-005-00 (April 25, 2016).
The new failure mechanism being reported here was not known prior to the most recent laboratory testing. Thus, it was not possible for this new condition to have been precluded.
SAFETY SIGNIFICANCE
The specific scenario in which the new failure mechanism can plausibly occur is a highly unlikely event. Additionally, standing orders were already in place at the time of this event that directed the operators to take compensatory actions to preserve the safety function of the affected systems. Those orders will remain in effect until all modifications are complete. Thus, this condition does not represent a significant challenge to the health and safety of the public.
(NOTE: Energy Industry Identification System component function identifier and system name of each component or system referred to in the LER are annotated as (**XX**) and [XX], respectively.) Page 3
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