WO 16-0026, Technical Specification 5.6.8 - Post Accident Monitoring (PAM) Report

Technical Specification 5.6.8 - Post Accident Monitoring (PAM) Report

ML16172A059
Person / Time
Site:	Wolf Creek
Issue date:	06/08/2016
From:	Edwards J Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
WO 16-0026
Download: ML16172A059 (3)

Text

June 8, 2016 Stephen L. Smith Plant Manager WO 16-0026 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Reference:

Letter WO 15-0045, dated July 27, 2015, from S. L. Smith, WCNOC, to USN RC

Subject:

Docket No. 50-482: Technical Specification 5.6.8 - Post Accident Monitoring (PAM) Report Gentlemen:

The Attachment provides the PAM Report for the inoperability of the Reactor Vessel Water Level Function for greater than 7 days. Wolf Creek Generating Station Technical Specification (TS) 5.6.8, "PAM Report," requires the submittal of the report within 14 days after entry into Condition F of TS 3.3.3, "Post Accident Monitoring (PAM) Instrumentation." Condition F of TS 3.3.3 was entered on May 28, 2016. This condition was entered due to Reactor Vessel Level Indicating System (RVLIS) 'A' train (TS Table 3.3.3-1, Function 5) being inoperable while the

'B' train RVLIS was inoperable.

This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-4093, or Cynthia R. Hafenstine (620) 364-4204.

~~es  ;~ L. Edwards II f/

Stephen L. Smith SLS/rlt Attachment cc: M. L. Dapas (NRC), w/a C. F. Lyon (NRC), w/a N. H. Taylor (NRC), w/a Senior Resident Inspector (NRC), w/a P.O. Box 411 /Burlington, KS 66839 I Phone: (620) 364-8831 An Equal Opportunity Employer M/F/HCNET

Attachment to WO 16-0026 Page 1 of 2 Technical Specification 5.6.8 - Post Accident Monitoring (PAM) Report

Background

On June 13, 2015, the 'B' train of Reactor Vessel Level Indication System (RVLIS) failed. A PAM report was submitted on July 27, 2015 (Reference). On May 21, 2016, Control Room operators observed erratic behavior on the level indicator associated with transmitter BBLT1312 for the 'A' train of Reactor Vessel Level Indication System (RVLIS). At 1930 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.34365e-4 months <br /> Central Daylight Time (CDT),

Technical Specification (TS) 3.3.3, "Post Accident Monitoring (PAM) Instrumentation," Condition C was entered when the 'A' train Reactor Vessel Water Level channel was determined to be inoperable. TS Table 3.3.3-1, Function 5, "Reactor Vessel Water Level," requires 2 channels to be OPERABLE.

Required Action C.1 of TS 3.3.3 requires restoring all but one channel to OPERABLE status within 7 days. On May 28, 2016, TS 3.3.3 Condition F was entered when the Required Action and associated Completion Time of Condition C was not met. Required Action F.1 requires initiation of action in accordance with TS 5.6.8, "PAM Report," and requires that a report be submitted within 14 days after entry into Condition F.

Reactor Vessel Water Level is a Type B, Category 1 variable provided for verification and long term surveillance of core cooling. It is also used for accident diagnosis and to determine reactor coolant inventory adequacy. The RVLIS provides an indication of reactor vessel water level from the bottom of the reactor vessel to the top of the reactor vessel during natural circulation conditions and an indication of reactor core and internals pressure drop for any combination of operating reactor coolant pumps.

The RVLIS consists of four reactor vessel water level indicators divided into two separate trains; each includes a narrow range and wide range indication. A channel is considered a train. A channel is considered OPERABLE when both its narrow range and wide range indicators are OPERABLE. In this case the wide range indication has an intermittent issue. It provides accurate data most of the time but cannot be considered OPERABLE in this condition.

Preplanned Alternate Method of Monitoring Alternate means of monitoring reactor vessel water level are available to Control Room operators while both trains of RVLIS are not OPERABLE. Additional PAM instrumentation that provides for verification of core cooling and long term surveillance include the reactor coolant system subcooling monitor (Function 4), pressurizer level indication (Function 11), and core exit temperature (Functions 14, 15, 16, and 17).

Cause of lnoperability On May 21, 2016, Control Room operators observed erratic behavior on the level transmitters BBLT1312 on the Nuclear Plant Information System (NPIS). Further testing did not find a definitive cause for the failure of BBLT1312.

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Attachment to WO 16-0026 Page 2 of 2 Plans and Schedule for Restoring the Instrumentation Channel of the Function to Operable Status Though the RVLIS level transmitter is located in the Auxiliary Building, access is required to the Reactor Cavity and Seal Table Area inside Containment for normal calibration of the transmitter.

These areas are inaccessible to personnel while operating at power due to radiological conditions in this area that prohibit access by plant personnel. There is a potential methodology that could be used to change and calibrate BBLT1312, but the risk of personnel injury, equipment damage, and loss of additional indicators cannot be justified at this time. The RVLIS indicator is available but unreliable, and this work could make the channel completely unavailable. Necessary corrective actions are planned for Refueling Outage 21 (Fall 2016) unless the actions are taken during a forced outage prior to the refueling outage.