ML102940472

McGuire 1 and 2 - RAI Regarding License Amendment to Relocate Specific Surveillance Frequency Requirements to a Licensee-Controlled Program Using a Risk-Informed Justification

ML102940472
Person / Time
Site:	McGuire, Mcguire
Issue date:	10/21/2010
From:	Thompson J H Plant Licensing Branch II
To:	Ashe K L, Hentz L A Duke Energy Carolinas
Thompson Jon, NRR/DORL/LPL 2-1, 415-1119
References
TAC ME3724, TAC ME3725
Download: ML102940472 (2)

Text

From: Thompson, Jon Sent: Thursday, October 21, 2010 3:42 PM To: Ashe, Ken; Hentz, Lee A

Subject:

RAI REGARDING LICENSE AMENDMENT TO RELOCATE SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE-CONTROLLED PROGRAM USING A RISK-INFORMED JUSTIFICATION Mr. Hentz, The following RAI from the Nuclear Regulatory Commission (NRC) staff pertains to the LAR to relocate specific surveillance frequency requirements to a licensee-controlled program using a risk-informed justification for McGuire 1 and 2 as described in the letter dated March 31, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML100920160), submitted by Duke Energy Carolinas, LLC (the licensee):

1. Table 2-1 of Attachment 2 identifies specific unresolved "gaps" of the McGuire Nuclear Station probabilistic risk assessment (PRA) internal events model to meeting the American Society of Mechanical Engineers PRA standard Capability Category II supporting requirements. In the column labeled "Importance to 5b Application," the licensee asserts, for some specific supporting requirements which are not met at Capability Category II, that:

i) Certain gaps will be assessed on a case-by-case basis ii) The gap has no or minimal impact on surveillance test exceptions.

Asserting that certain gaps are to be assessed on a case-by-case basis is inconsistent with Nuclear Energy Institute (NEI) 04-10, Revision 1, which specifically requires Capability Category II. Further, NEI 04-10 requires all gaps to Capability Category II to be assessed via sensitivity studies. This position was accepted by the NRC staff in its safety evaluation of NEI 04-10 Revision 1. Therefore, notwithstanding the assertions in Table 2-1 regarding Capability Category I, each supporting requirement not meeting Capability Category II must be further evaluated by sensitivity studies when applying the internal events PRA model for this application.

With regard to item ii above, the gaps cannot be dispositioned a priori, since this would also conflict with NEI 04-10 which did not identify any supporting requirements that were not required for this application. Again, such gaps must be evaluated by sensitivity studies for each surveillance frequency change.

The licensee is therefore requested to confirm that their plant program for control of surveillance frequencies includes a requirement to assess all open gaps to Capability Category II of the standard via sensitivity studies for each application of the NEI 04-10 methodology, and does not rely upon any a priori assessment of the relevance of the supporting requirement.

2. In Table 2-1, Attachment 2 of the submittal, gap #14 identifies twelve supporting requirement deficiencies to the model. The licensee dispositions this gap as documentation issues. The NRC staff requires a detailed clarification for all supporting requirements that were assessed against Capability Category II technical requirements and characterized as model documentation issues.

Please contact me, if you are not able to respond to these RAIs within 30 days.

Sincerely, Jon Thompson, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation E-mail Properties Mail Envelope Properties ()

Subject:

RAI REGARDING LICENSE AMENDMENT TO RELOCATE SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE-CONTROLLED PROGRAM USING A RISK-INFORMED JUSTIFICATION Sent Date: 10/21/2010 3:35:21 PM Received Date: 10/21/2010 3:41:00 PM From: Thompson, Jon

Created By: Jon.Thompson@nrc.gov

Recipients:

Ken.Ashe@duke-energy.com (Ashe, Ken)

Tracking Status: None Lee.Hentz@duke-energy.com (Hentz, Lee A)

Tracking Status: None

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MESSAGE 11948 10/21/2010

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Priority: olImportanceNormal ReplyRequested: False Return Notification: False

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