AEP-NRC-2020-59, for Donald C. Cook Nuclear Plant (CNP) Unit 2 - Report Per Technical Specification 5.6.6, Lnoperability of Unit 2, Post Accident Monitoring, Containment Water Level

for Donald C. Cook Nuclear Plant (CNP) Unit 2 - Report Per Technical Specification 5.6.6, Lnoperability of Unit 2, Post Accident Monitoring, Containment Water Level

ML20248H483
Person / Time
Site:	Cook
Issue date:	08/27/2020
From:	Scarpello M Indiana Michigan Power Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
AEP-NRC-2020-59
Download: ML20248H483 (3)

Text

m INDIANA Indiana Michigan Power MICHIGAN Cook Nuclear Plant

. POWER One Cook Place Bridgman, Ml 49106 A unit ofAmerican Electric Power lndianaMichiganPower.com August 27, 2020 AEP-NRC-2020-59 10 CFR 50.4 10 CFR 50.36 Docket Nos.: 50-316 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Report per Technical Specification 5.6.6, lnoperability of Unit 2, Post Accident Monitoring, Containment Water Level Indiana Michigan Power Company, the licensee for Donald C. Cook Nuclear Plant (CNP) Unit 2, is sending this report pursuant to CNP Technical Specification (TS) 3.3.3, "Post Accident Monitoring (PAM) Instrumentation" and TS 5.6.6, "Post Accident Monitoring Report." The enclosure to this letter contains the report regarding the inoperability of a Unit 2 Containment Water Level Monitor. The Train B Lower Containment Water Level Monitor, 2-NLl-320, was discovered to be inoperable during a board walk down on July 15, 2020. This report is being submitted due to 2-NLl-320 being inoperable for greater than 30 days. The information required by TS 5.6.6, "Post Accident Monitoring Report" is enclosed.

There are no new or revised commitments in this letter. Should you have any questions, please contact me at (269) 466-2649.

i;.(J~

Michael K. Scarpello Regulatory Affairs Director DLW/mll

Enclosure:

Donald C Cook, Unit 2 Report per Technical Specification 5.6.6 lnoperability of Post-Accident Monitoring Instrument Containment Water Level

U. S. Nuclear Regulatory Commission AEP-NRC-2020-59 Page 2 R. J. Ancona - MPSC EGLE - RMD/RPS J. B. Giessner - NRC Region Ill NRC Resident Inspector S. P. Wall - NRC Washington, D.C.

A. J. Williamson - AEP Ft. Wayne, w/o enclosures

Enclosure 1 to AEP-NRC-2020-59 Donald C Cook, Unit 2 Report per Technical Specification 5.6.6 lnoperability of Post-Accident Monitoring Instrument Containment Water Level Description of Condition On July 15, 2020, during a board walkdown, the Train B Containment Water Level Monitor, 2-NLl-320, was determined to be inoperable. The suspected cause of the failure of 2-NLl-320 is the test injection switch, 2-NLS-320, associated with the containment water level monitor. An attempt was made to repair 2-NLS-320 online and it was discovered that the mounting brackets in the cabinet blocked access for repair. 2-NLS-320 needs to be removed from the cabinet to successfully complete the repair and restore Train B Containment Water Level Monitor to operability. The wiring for 2-NLS-320 is tie-wrapped with the wiring for the other instruments in the cabinet. Based on a review of the other instruments in the cabinet, the physical movement of adjacent wiring poses an unacceptable level of risk while online. The repair will be completed at the next available opportunity.

Per Technical Specification (TS) LCO 3.3.3, "Post Accident Monitoring (PAM) Instrumentation,"

Condition A, 2-NLl-320 is required to be restored to OPERABLE status within 30 days. TS LCO 3.3.3, Condition B, requires submittal of a report, in accordance with TS 5.6.6 "Post Accident Monitoring Report," within 14 days of exceeding the Condition A Completion Time. The 30-day Completion Time for TS LCO 3.3.3, "Post Accident Monitoring (PAM) Instrumentation," Condition A, was reached on August 14, 2020.

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. The Containment Water Level Monitor is a Type A, Category 1 variable provided for determination of adverse containment conditions (per Regulatory Guide 1.97, Revision 3, ML003740282). Donald C. Cook Nuclear Plant has Train A and Train B Containment Water Level channels (NLl-321 and NLl-320). Each channel is capable of measuring from 599' 3" elevation to 614' elevation (containment floor level to maximum flood level).

Cause of lnoperability The apparent cause of inoperability of 2-NLl-320 is a faulty test injection switch (2-NLS-320).

Preplanned Alternate Method of Monitoring The Containment Water Level Monitor consists of two redundant trains with 1 channel each. Train A, 2-NLl-321, will remain operable and available while Train B, 2-NLl-320, is inoperable. Additionally, the following instruments in containment will be used, if necessary, to monitor containment water level while 2-NLl-320 is inoperable:

2-NLl-311 - Lower Containment Sump Train A Level Indicator 2-NLA-31 O - Lower Containment Sump Train B Level Alarm 2-NLl-301 - Containment Recirculation Sump Level Switch - Train A 2-NLl-300 - Containment Recirculation Sump Level Switch - Train B 2-NLl-331 - Containment Water Level Recirculation Level Switch - Train A 2-NLl-330 - Containment Water Level Recirculation Level Switch - Train B Plans and Schedule for Restoring Functionality 2-NLS-320 will be repaired at the next available opportunity which requires Unit 2 to be below Mode 3.

A work order was created and planned to repair 2-NLS-320 during the next Unit 2 refueling outage (RFO). The Unit 2 Cycle 26 RFO is planned for spring 2021. If Unit 2 is taken offline prior to the RFO, 2-NLS-320 will be repaired at that time.