ML13098A778

Request for Additional Information Following 4/3/13 Calculation Audit, Technical Specification Changes to Support Installation of GE Hitachi Power Range Neutron Monitoring System; Implementation of Arts/Mellla

ML13098A778
Person / Time
Site:	Columbia
Issue date:	04/08/2013
From:	Lyon F Plant Licensing Branch IV
To:	Huiatt M Energy Northwest
Lyon C
References
TAC ME7905
Download: ML13098A778 (2)

Text

Lent, Susan From: Lyon, Fred Sent: Monday, April 08,20132:49 PM To: Huiatt Jr, Michael A. (Tony)

Cc: Singh, Gursharan; Thorp, John; Alvarado, Rossnyev

Subject:

Additional RAls from 4/3/13 PRNM/ARTS/MELLLA Calculation Audit (TAC No. ME7905)

Attachments: 4~3-13 audit RAls.docx Attached are the RAls from last Wednesday's calculation audit. Thanks, Fred 1

NRC Audit of Columbia Generating Station (CGS; Energy Northwest, EN)

Setpoint Calculations RAls 17 and 18 Location: NRC TWFN These notes summarize the NRC staff questions raised during the audit exit meeting on April 3, 2013.

1) Is EN planning to use filtered or unfiltered set points for establishing the low/intermediate or high power trip setpoint (

Reference:

Attachment A to NEDC-33507P)? Document how the use of filtered or unfiltered values will be determined and explicitly state how these limits will be conservatively applied for implementation of PRNM/ARTS/MELLLA at CGS.

2) RAI17 clarification (RAI regarding use of 3-Sigma errors): Not all 3-Sigma errors are explained; specifically, the use of 3-Sigma for the rod block monitor tracking PMA trip set points needs explanation.

3) OPRM Set Point Bases: What are the bases for the set points? This question has been resolved (information was located in NEDC-33685).

4) How are as-found tolerance and as-left tolerance values defined by EN for CGS? Define the error terms used in determining their values. TSTF-493 provides guidance, but does not specify the error terms, for calculating these numbers.

5) Explain how the 95/95 probability/confidence criteria is being implemented in the GEH setpoint methodology for the set points under review.