ML25078A046
| ML25078A046 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 03/18/2025 |
| From: | Dia K Nebraska Public Power District (NPPD) |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| N152025021 | |
| Download: ML25078A046 (1) | |
Text
N Nebraska Public Power District Alway there when you need us N152025021 March 18,2025 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001
Subject:
Technical Specifications Section 5.6.6, Post Accident Monitoring lnstrumentation 14-Day Report Cooper Nuclear Station, Docket No. 50-298, Renewed License No. DPR-46 The purpose of this letter is to submit the Post Accident Monitoring lnstrumentation Report as required by the Cooper Nuclear Station Technical Specifications (TS) Section 5.6.6, "Post Accident Monitoring (PAM) lnstrumentation Report."
The report, which is provided as an attachment to this letter, is based on the inoperability on February 8,2025, of the open limit switch for the "C" inboard Main Steam lsolation Vatve. this condition required entry into TS Section 3.3.3.1, "Post Accident Monitoring (PAM) lnstrumentation," Condition A, due to an inoperable indication channel for Function 5 in Table 3.3.3.1-1. Condition A requires restoration of the required indication channel to an operable status within 30 days. Resolution of this issue within the 30-day requirement was not feasible due to the outage conditions and drywell entry required to complete the necessary repairs. With the channel not restored to operable within 30 days, a report is required in accordance with TS Section 5.6.6.
Accordingly, the attached report outlines the preplanned alternate method of monitoring and the apparent cause along with the plans and schedule for restoring the instrument channelto an operable status.
No regulatory commitments are being made in this letter. Should you have any questions concerning this matter, please contact Linda Dewhirst, Regulatory Affairs and Compliance Manager, (402) 825-5416.
Sincerel al ta Site Vice President ljo
Attachment:
Post Accident Monitoring lnstrumentation 14-Day Report COOPER NUCTEAR STATION P.O. Box 98 / Brownville, NE 68321-0098 Telephone: (402) 825-3811 / Fax: (a01825-5211 www.nppd.com
N1S2025021 Page 2 ot 2 cc: Regional Administrator Mattachment USNRC - Region lV Cooper Project Manager dattachment USNRC - NRR Plant Licensing Branch lV Senior Resident lnspector dattachment USNRC - CNS NPG Distribution Mattachment CNS Records w/attachment
N152025021 Attachment Page 1 of 1 Post Accident Monitoring lnstrumentation 14-Day Report Preplanned Alternate Method of Monitorinq Alternate method of monitoring the open function for the "C" inboard Main Steam lsolation Valve (MSIV) has been implemented. The "Valve Closed" indicating lamp currently does not change state to off when the valve is in the fully open position, thus indicating intermediate position (both the "Valve Open" and "Valve Closed" indicators illuminated) when the valve is in both the fully open and the intermediate positions. The "Valve Open" indicating lamp will change state to off when the valve is in its fully closed position. The "C" inboard MSIV will indicate the closed position normally with only the "Valve Open" indicating lamp off, and the "Valve Closed" indicating lamp on.
ln addition, the position indication for the outboard MSIV on the "C" Main Steam Line is fully functional and can be used to verify steam line isolation. Operations personnel have also been instructed in the use of other indications, such as total steam flow and reactor pressure.
This alternate method provides an acceptable means of indication to ensure the MSIV isolation function has been accomplished. This guidance has been communicated to Operations personnel. The MSIV indication anomaly has been entered into the Corrective Action Program for final resolution.
Cause of the lnooerabilitv The most likely cause of the loss of indication from the open limit switch for the "C" inboard MSIV is a premature failure of the limit switch. This limit switch is located inside the drywell and is not accessible during plant operation. The cause analysis will be finalized when drywell entry is possible.
Plans and Schedule for Returninq Function to Operable Status Repair of the open limit switch for the "C" inboard MSIV requires a plant outage with drywell entry. The limit switch will be repaired as opportunity allows and no later than the next scheduled refueling outage.