U-604357, Special Report: Inoperable Drywall High Range Gamma Radiation Monitor

Special Report: Inoperable Drywall High Range Gamma Radiation Monitor

ML17192A258
Person / Time
Site:	Clinton
Issue date:	07/05/2017
From:	Stoner T Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
U-604357
Download: ML17192A258 (2)

Text

Clinton Power Station 8401 Power Road Clinton, IL 61727 ~ Exelon Generation.

U-604357 10CFR50.73 SRRS 5A.108 July 5 ,* 201 7 U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, D.C. 20555-0001 Clinton Power Station, Unit 1 Facility Operating License No. NPF-62 NRG Docket No. 50-461

Subject:

Special Report: Inoperable Drywall High Range Gamma Radiation Monitor In accordance with Clinton Power Station (CPS) Technical Specification (TS) 3.3.3.1, Post Accident Monitoring (PAM} Instrumentation, Required Action 8.1, Exelon Generation Company, LLC (EGG) is submitting the following Special Report concerning the inoperability of Drywall High Range Gamma Radiation Monitor, 1 RIX-CM060.

Description of Event On May 27, 2017 with unit in Mode 4, during the performance of procedure 9437.65, Containment/Drywell High Range Gamma Monitor 1RIX-CM059 (60, 61, 62) Channel Calibration, the monitor was discovered unresponsive when exposed to a high range gamma source. However, the plant was not required to have 1RIX-CM060 operable at the time as TS 3.3.3.1 applies only in Modes 1 and 2.

On May 28, 2017 at 1814 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.90227e-4 months <br />, upon entry into Mode 2 for plant startup from refueling outage C1R17, TS 3.3.3.1 Required Action A.1 was entered, requiring restoration of 1RIX-CM060 to operable status in 30 days.

Action Taken Troubleshooting on May 28, 2017 under Work Order 04644783 verified proper operation of the power supply, signal input circuit, and metering circuit. In addition, electronics, cabling, and equipment outside the drywell have been investigated with no deficiencies identified.

Vendor support to assist in troubleshooting has been scheduled the week of 7/10/17. If no cause external to the drywall can be determined, additional troubleshooting and restoration will be performed during the next refueling outage C1R18 due to radiation considerations.

Cause of lnoperability The cause of inoperability is still under investigation. A follow up report will be issued upon determination of the cause of the inoperability.

Should you have any questions concerning this report, please contact Mr. Dale Shelton, Regulatory Assurance Manager, at (217) 937-204.

ResP.ectfully, 0 l-4::Q_ s (Z.l>t>US'J -r* K""""""~

Th~ore  :. Stoner Site Vice President Clinton Power Station NAS/bsz cc:

Regional Administrator- NRC Region Ill NRC Senior Resident Inspector - Clinton Power Station Office of Nuclear Facility Safety - Illinois Emergency Management Agency