CNS-14-035, Submittal of Post Accident Monitoring (PAM) Report

Submittal of Post Accident Monitoring (PAM) Report

ML14078A029
Person / Time
Site:	Catawba
Issue date:	03/17/2014
From:	Henderson K Duke Energy Carolinas, Duke Energy Corp
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNS-14-035
Download: ML14078A029 (4)

Text

Kelvin Henderson DUKE ENERGY. Vice President Catawba Nuclear Station Duke Energy CN01VP I 4800 Concord Road York, SC 29745 CNS-14-035 o: 803.701.4251 f: 803.701.3221 March 17, 2014 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555

Subject:

Duke Energy Carolinas, LLC (Duke Energy)

Catawba Nuclear Station, Unit 2 Docket No. 50-414 Post Accident Monitoring (PAM) Report Pursuant to 10 CFR 50.4 and Technical Specifications (TS) 3.3.3 and 5.6.7, please find attached the subject report. This report documents the inoperability of Loop A of the Unit 2 Reactor Coolant System Wide Range Cold Leg Temperature indication, which has been inoperable since January 31, 2014.

There are no regulatory commitments contained in this letter or its attachment.

This event is considered to be of no significance with respect to the health and safety of the public.

If there are any questions on this report, please contact L.J. Rudy at (803) 701-3084.

Sincerely, Kelvin Henderson Vice President, Catawba Nuclear Station LJPRs Attachment Awl www.duke-energy.com

Document Control Desk Page 2 March 17, 2014 xc (with attachment):

V.M. McCree Regional Administrator U.S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 J.C. Paige (addressee only)

NRC Project Manager U.S. Nuclear Regulatory Commission Mail Stop 8-G9A 11555 Rockville Pike Rockville, MD 20852-2738 G.A. Hutto, III NRC Senior Resident Inspector Catawba Nuclear Station

Post Accident Monitoring (PAM) Report This report is being submitted as a result of the Unit 2 Reactor Coolant System (RCS) Loop A Wide Range Cold Leg Temperature function being inoperable. The inoperability is attributed to a failure of its associated Resistance Temperature Detector (RTD). This report is being submitted in accordance with Technical Specification (TS) 3.3.3, "Post Accident Monitoring (PAM) Instrumentation" and TS 5.6.7, "PAM Report". The inoperable channel is one of the two channels required by TS 3.3.3 Table 3.3.3-1, "Post Accident Monitoring Instrumentation",

Function 2.

The Bases for TS 3.3.3 states that Type A and Category 1 variables are required to meet NRC Regulatory Guide (RG) 1.97 Category 1 design and qualification requirements for seismic and environmental qualification, single failure criterion, utilization of emergency standby power, immediately accessible display, continuous readout, and recording of display. Catawba's RG 1.97 analysis describes how many channels of each particular PAM function are recorded. The affected function provides the control room with two redundant means of indication, both of which are credited as PAM indication. They are needle gauge 2NCP5860 and chart recorder 2NCCR5860. Since the number of gauge indications as committed to in Catawba's RG 1.97 analysis is not met (i.e., one operable versus two required), the TS requirement for this function is not met. Therefore, with only one operable gauge indication, this event is NRC reportable. It should be noted that in addition to the remaining operable channel of Wide Range Cold Leg Temperature, other operable means of PAM instrumentation for monitoring RCS temperature include the Wide Range Hot Leg Temperature and Core Exit Temperature (thermocouple) functions.

The following is a brief timeline of the events concerning this issue:

January 31, 2014 - Unit 2 RCS Cold Leg Temperature - Loop A was declared inoperable at 0918 hours0.0106 days <br />0.255 hours <br />0.00152 weeks <br />3.49299e-4 months <br /> due to required calibration. There were no known issues following the calibration and all indications were normal; however, a functional check still needed to be performed.

February 3, 2014 - Monthly performance test ( the functional check) was scheduled but was not performed due to erratic indications in the control room. Maintenance was first engaged regarding the indications on this function. The work was made an emergent priority commensurate with the TS 30-day Required Action.

February 5, 2014 - The issue was entered into the Catawba Corrective Action Program. A work request was written to troubleshoot the continued erratic indication.

February 7-8, 2014 - Monthly performance test was performed. The acceptance criterion was not met for this function. The failure to meet the acceptance criterion was entered into the Catawba Corrective Action Program.

February 10-11, 2014 - The work was upgraded to highest priority for completion within 7 days.

Maintenance performed initial troubleshooting of this function. Initial indications were inconclusive as to the exact problem. Maintenance and Engineering developed further troubleshooting instructions.

1

February 14, 2014 - Maintenance determined that this function's RTD had failed and needed to be replaced. The failed RTD could not have been anticipated.

The cause of the RTD failure cannot be determined since Unit 2 is presently in Mode 1 (Power Operation). An investigation into the failure mode will be conducted once the RTD is replaced.

On February 17, 2014, Catawba requested an exigent TS change for TS 3.3.4 "Remote Shutdown System", as the affected function's channel also supports the Remote Shutdown System. The NRC approved the exigent TS change request on February 27, 2014. This allowed Unit 2 to continue in Mode 1 operation until the Spring 2015 refueling outage or until an earlier outage which supports RTD replacement.

2