ML14211A133

Fyi: Follow Up Question for Columbia, Regarding Implementation of TSTF-493, Option a

ML14211A133
Person / Time
Site:	Columbia
Issue date:	07/30/2014
From:	Lyon F Division of Operating Reactor Licensing
To:	Williams L L Energy Northwest
References
MF2863
Download: ML14211A133 (3)

Text

1 NRR-PMDAPEm Resource From: Lyon, Fred Sent: Wednesday, July 30, 2014 6:37 AM To: Williams, Lisa L. (llwillia ms@energy-northwest.com)

Cc: George, Andrea

Subject:

FYI: Follow up question for Columbia, regarding implementation of TSTF-493, Option A (TAC No. MF2863)

Attachments:

Setpoint terminology.pdfBased on our phoncon yesterday, this is the information that EICB requires to continue our safety evaluation of the LAR (MF2863).

NRC staff expects to see at least the following ingredient s in the licensee's setpoint methodology. Please refer to the attached slide for the setpoint terminology.

1. Licensee's methodology for consistently establishing adequate margins (Total Loop Uncertainty Allowance) between the limiting and/or nominal trip setpoints and the plant analytical limits. These margins should be reflective of NRC staff guidance (e.g., use of accurate estimates of statistical (95/95) and bias terms for channel performance errors, use of appropriate channel performance modeling assumptions that reflect actual plant engineering and maintenance practices, controlled data, etc.)

2. Licensee's methodology for establishing conservatively small, but practically-applied acceptance tolerance bands for "as-found" channel performance deviation, and "as-left" post-calibration setting tolerances that can be used to assure a tight control on allowed setpoint deviations, while permitting a knowledgeable assessment of channel operability.

3. It would help the staff to see how these margins and tolerances relate to the Allowable Value published in the plant Technical Specifications. This could be in the form of a Figure that shows the relationship among all the values presented, perhaps with a few examples of the attached slide with the values filled in.

Please let me know if you have any additional questions. Thanks, Fred Hearing Identifier: NRR_PMDA Email Number: 1460 Mail Envelope Properties (Fred.Lyon@nrc.gov20140730063700)

Subject:

FYI: Follow up question for Columbia, regarding implementation of TSTF-493, Option A (TAC No. MF2863) Sent Date: 7/30/2014 6:37:12 AM Received Date: 7/30/2014 6:37:00 AM From: Lyon, Fred Created By: Fred.Lyon@nrc.gov Recipients: "George, Andrea" <Andrea.George@nrc.gov> Tracking Status: None "Williams, Lisa L. (llwilliams@energy-northwest.com)" <llwilliams@energy-northwest.com> Tracking Status: None Post Office: Files Size Date & Time MESSAGE 1600 7/30/2014 6:37:00 AM Setpoint terminology.pdf 80952 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

U.S. Nuclear Regulatory Commission RIS 2006-17 Basic Relationships Safety LimitAnalytical LimitTotal Loop Allowable Value

Uncertainty AllowanceLimiting Trip SetpointAs-Found (Upper Limit)SettingToleranceNominal Trip Setpoint (As-Left Band)As-Found (Lower Limit) 1