05000298/LER-2015-003, Regarding Failure of Main Steam Isolation Limit Switches Results in a Condition Prohibited by Technical Specifications and Also a Common Cause Inoperability
| ML15216A361 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 07/28/2015 |
| From: | Limpias O Nebraska Public Power District (NPPD) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NLS2015093 LER 15-003-00 | |
| Download: ML15216A361 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 2982015003R00 - NRC Website | |
text
N Nebraska Public Power District Always there whent you need us NLS201 5093 July 28, 2015 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001
Subject:
Licensee Event Report No. 2015-003-00
_Cooper Nuclear Station, Docket No. 50-298, DPR-46
Dear Sir or Madam:
The purpose of this correspondence is to forward Licensee Event Report 2015-003-00.
There are no new commitments contained in this letter.
Ve President Nuclear-Chief Nuclear Officer
/ho Attachment: Licensee Event Report 2015-003-00 cc:
Regional Administrator w/attachment USNRC - Region IV Cooper Project Manager w/attachment USNRC - NRR Project Directorate IV-1 Senior Resident Inspector w/attachment USNRC - CNS SRAB Administrator w/attachment NIPG Distribution w/attachment INPO Records Center w/attachment via ICES entry SORC Chairman w/attachment CNS Records w/attachment 2i~~
COOPER NUCLEAR STATION P.O. Box 98 / Brownville, NE 68321-0098 Telephone: (402) 825-3811 / Fax:. (402) 825-5211 ww.nppd.com
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BYO0MB: NO. 31 50-0104 EXPIRES: 0113112017 02-201o,,)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
I q
- 1. FACILITY NAME
- 2. DOCKET Cooper Nuclear Station 05000298 associated RPS relay were declared inoperable and the associated RPS channel was placed in trip per Technical Specifications (TS) LCO 3.3.1.1, Condition A.
In May 2015, Quarterly Surveillance Testing was performed on the MSIVs. At this time limit switches associated with inboard MSIV A and inboard MSIV B also failed to actuate their associated RPS relay. The limit switches and associated RPS relay were declared inoperable and the associated RPS channel was placed in trip per TS LCO 3.3.1.1, Condition A, resulting in a continuous half scram.
With the plant being in an increased risk of an inadvertent full scram due to placing the RPS channel logic in a tripped condition, a decision was made to shutdown the plant and replace the limit switches. CNS shutdown on May 29, 2015, and the limit switches were replaced. The limit switches that were removed are being evaluated for cause.
The event is currently under investigation. CNS will provide additional event details, the safety significance, cause evaluation, and corrective action(s) to reduce the probability of recurrence in a supplement to this Licensee Event Report.
BASIS FOR REPORT This event is potentially reportable under 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications and 10 CFR 50.73(a)(2)(vii), common cause inoperability.
Other criteria, if determined to be applicable, will be provided in the supplemental report.
PREVIOUS EVENTS There have been no events reported in the last three years related to MSIV limit switches.