05000458/LER-2014-001, Regarding Unanalyzed Condition Associated with Unfused Ammeters in DC Battery Indication Circuits
| ML14079A078 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 03/10/2014 |
| From: | Olson E Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RBG-47448 LER 14-001-00 | |
| Download: ML14079A078 (4) | |
| 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 |
| 4582014001R00 - NRC Website | |
text
p 'Enter9W Entergy Operations, Inc.
River Bend Station 5485 U. S. Highway 61 N St. Francisville, LA 70775 Tel 225 381 4374 Fax 225 381 4872 eolson@entergy.com Eric W. Olson Site Vice President RBG-47448 March 10, 2014 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
'Subject:
Licensee Event Report 50-458 / 2014-001-00 River Bend Station - Unit 1 Docket No. 50-458 License No. NPF-47 RBF1-14-0031
Dear Sir or Madam:
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 Mr. Joseph Clark at 225-381-4177.
Sincerely, EWO/dhw Enclosure
Licensee Event Report 50-458 / 2014-001-00 March 10, 2014 RBG-47448 Page 2 of 2 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 reporting)
Central Records Clerk Public Utility Commission of Texas 1701 N. Congress Ave.
Austin, TX 78711-3326 Department of Environmental Quality Office of Environmental Compliance Radiological Emergency Planning and Response Section JiYoung 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: 01/3112017 (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.
Send comments regarding burden estimate to the FOIA, Privacy and Information Collections (E
)
Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by LICENSEE EVENT REPORT (LER) 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 20503. If a means used to impose an information collection does not display a currently valid OMB digits/characters for each block) control 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
- 4. TITLE Unanalyzed Condition Associated With Unfused Ammeters in DC Battery Indication Circuits
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MO FACIULTY NAME DOCKET NUMBER NUMBER NO.
MOT A
ER05000 FACILITY NAME DOCKET NUMBER_
01 09 2014 2014 -
001 00 03 10 2014 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
D 20.2201(b)
[
20.2203(a)(3)(i)
[
50.73(a)(2)(i)(C)
[]
50.73(a)(2)(vii) 1 20.2201(d)
[
20.2203(a)(3)(ii)
[
50.73(a)(2)(ii)(A)
E] 50.73(a)(2)(viii)(A)
D 20.2203(a)(1)
[
20.2203(a)(4) 50.73(a)(2)(ii)(B)
[]
50.73(a)(2)(viii)(B)
__ 20.2203(a)(2)(i)
E] 50.36(c)(1)(i)(A)
[]
50.73(a)(2)(iii)
E] 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL
[]
20.2203(a)(2)(ii)
[] 50.36(c)(1)(ii)(A)
El 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)
[j 73.71(a)(4) 100 El 20.2203(a)(2)(iv)
[ 50.46(a)(3)(ii)
[] 50.73(a)(2)(v)(B)
[ 73.71(a)(5)
El 20.2203(a)(2)(v)
[
50.73(a)(2)(i)(A)
[] 50.73(a)(2)(v)(C)
OTHER 20.2203(a)(2)(vi)
[
50.73(a)(2)(i)(B) 50.73(a)(2)(v)(O)
Specify in Abstract below or in
REPORTED CONDITION On January 9, 2014, with the plant operating at 100 percent power, the final review of industry operating experience regarding the adverse effects of unfused direct current ammeter circuits in the main control room determined the described condition to be applicable to River Bend Station, resulting in a potentially unanalyzed condition with respect to 10 CFR 50 Appendix R analysis requirements.
River Bend Station does have unfused ammeter circuits. This normally is not a concern, since two failures are required to cause the problem described in the document referenced above; an ammeter lead must short to ground, and another lead of the opposite polarity must also short to ground. Either of these events by itself will result in an alann annunciation, but not cause equipment damage. This allows for locating and repairing the problem before the second failure occurs. However, during a fire, there is a greater chance that these two failures could happen simultaneously, or before a single failure can be repaired. If an unfused ammeter lead shorts to ground while another conductor of the opposite polarity shorts to ground, the unfused path through the lead could allow enough current to flow that the lead will heat up and damage other wiring, with potentially adverse effects on the ability to safely shut down the plant in the event of a fire in the main control room.
This condition is being reported in accordance with 10 CFR 50.73(a)(2)(ii)(B). Interim compensatory measures have been implemented.
CAUSAL ANALYSIS This condition has existed since the plant was constructed. Neither the original design criteria nor any industry standards in effect at the time accounted for the possibility of the multiple short-to-ground failure mode and therefore, did not require overcurrent protection for remote ammeter circuits.
CORRECTIVE ACTION
This condition was documented in the station's corrective action program. Compensatory measures were established to restore margin potentially reduced by postulated fire scenarios. The compensatory actions credit operator presence in the plant for maintaining heightened awareness and taking action to minimize fire hazards. Compensatory actions are incorporated in pertinent operating procedures. The compensatory actions remain in effect.
SAFETY SIGNIFICANCE
There have been no actual adverse safety consequences resulting from the reported condition. The administrative controls of the fire protection program, the availability of fire detection and suppression systems, and a trained on-site fire brigade all combine to make it highly unlikely that a fire could occur and progress in a manner that actually leads to the event postulated in this scenario.