AEP-NRC-2023-56, Report Per Technical Specification 5.6.6 for Inoperability of Unit 1 Post Accident Monitoring Reactor Coolant (Loop 3 Cold Leg) Wide Range Temperature Recorder Thermal Sensor

Report Per Technical Specification 5.6.6 for Inoperability of Unit 1 Post Accident Monitoring Reactor Coolant (Loop 3 Cold Leg) Wide Range Temperature Recorder Thermal Sensor

ML23354A136
Person / Time
Site:	Cook
Issue date:	12/20/2023
From:	Scarpello M Indiana Michigan Power Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
AEP-NRC-2023-56
Download: ML23354A136 (1)

Text

Indiana Michigan Power Cook Nuclear Plant One Cook Place Bridgman, Ml 49106 ind1anamich1ganpower.com An MP Company BOUNDLESS ENERG Y-December 20, 2023 AEP-NRC-2023-56 10 CFR 50.4 10 CFR 50.36 Docket No.: 50-315 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Donald C. Cook Nuclear Plant Unit 1 Report per Technical Specification 5.6.6 for lnoperability of Unit 1 Post Accident Monitoring Reactor Coolant (Loop #3 Cold Leg) Wide Range Temperature Recorder Thermal Sensor Indiana Michigan Power Company (l&M), the licensee for Donald C. Cook Nuclear Plant (CNP) Unit 1, determined on November 11, 2023, that a Reactor Coolant Wide Range Temperature Recorder Thermal Sensor (1-NTR-230 for Loop #3 Cold Leg) was inoperable. In accordance with Technical Specification (TS) 3.3.3, Post Accident Monitoring (PAM) Instrumentation, and TS 5.6.6, Post Accident Monitoring Report, l&M is providing, as the enclosure to this letter, the report required by TS 5.6.6.

There are no new or revised commitments in this letter. Should you have any questions, please contact Mr. Michael K. Scarpello, Director of Regulatory Affairs, at (269) 466-2649.

s;.nfL Michael K. Scarpello Regulatory Affairs Director KMH/sjh

Enclosure:

Donald C. Cook Nuclear Plant, Unit 1 Report per Technical Specification 5.6.6 for Reactor Coolant (Loop #3 Cold Leg) Wide Range Temperature Recorder Thermal Sensor Inoperable c:

EGLE - RMD/RPS J. B. Giessner - NRC Region Ill NRC Resident Inspector N. Quilico - MPSC R. M. Sistevaris - AEP Ft. Wayne S. P. Wall - NRC Washington, D.C.

A. J. Williamson - AEP Ft. Wayne

Enclosure to AEP-NRC-2023-56 Donald C. Cook Nuclear Plant, Unit 1 Report per Technical Specification 5.6.6 for Reactor Coolant {Loop #3 Cold Leg) Wide Range Temperature Recorder Thermal Sensor Inoperable Description of Condition On November 11, 2023, a Reactor Coolant Wide Range Temperature Recorder Thermal Sensor (1-NTR-230 for Loop #3 Cold Leg) failed high and was determined to be inoperable. 1-NTR-230 is required to be operable, in Modes 1, 2 and 3, in accordance with Technical Specification (TS) Limiting Condition Operation (LCO) 3.3.3, Post Accident Monitoring (PAM) Instrumentation.

Donald C. Cook Nuclear Plant (CNP) Unit 1 entered Mode 3, from scheduled Refueling Outage activities, on November 11, 2023. Therefore, TS LCO 3.3.3, Condition A was entered due to one required channel being inoperable, and requires 1-NTR-230 to be restored to OPERABLE status within 30 days. Replacement parts were unable to be procured to restore 1-NTR-230 to OPERABLE status. TS LCO 3.3.3, Condition B, requires action in accordance with TS 5.6.6 when Completion Time of Condition A is not met. TS 5.6.6, Post Accident Monitoring Report, requires the submittal of a report within 14 days of exceeding the Condition A Completion Time.

Background

The primary purpose of the PAM instrumentation is to display unit variables that provide information required by the control room operators during accident situations. Reactor Coolant System (RCS)

Hot and Cold Leg Temperatures are a Category 1 variable provided for verification of core cooling and long-term surveillance. RCS hot and cold leg temperatures are used to determine RCS subcooling margin. The RCS hot leg and cold leg channels each receive input from one resistance temperature detector (RTD). The channels provide indication over a range of O degrees Fahrenheit

(°F) to 700°F.

Cause of lnoperability 1-NTR-230 is inoperable due to a failed element in the field instrument. The failure occurred in MODE 3 during startup from the U1 C32 Refueling Outage. 1-NTR-230 was functioning normally prior to this refueling outage.

Preplanned Alternate Method of Monitoring Each of the four Cold Legs is instrumented with a wide range RTD, and the other three loops' wide range RTDs remain operable. The Loops 1, 2, and 4 Cold Leg wide range RTDs will be monitored when they are available (e.g., during normal operation). Only the Loops 1 and 3 instruments meet the requirements of Reg Guide 1.97 Category 1, so the Loop 1 instrument (1-NTR-210) will be monitored if Loops 2 and 4 indications become unavailable (e.g., due to loss of off-site power).

Plans and Schedule for Restoring Functionality 1-NTR-230 is not accessible while the unit is at power. 1-NTR-230 will be replaced at the next opportunity after procurement of replacement parts. Currently, the next opportunity is the refueling outage (scheduled Spring 2025) unless a Forced Outage of sufficient duration occurs resulting in the Unit entering Mode 5 or 6.