ML15068A090

NRR E-mail Capture - North Anna Units 1 and 2, Request for Information: Technical Specification Change Proposing Permanent FIFTEEN-YEAR Type a Test Interval

ML15068A090
Person / Time
Site:	North Anna
Issue date:	03/09/2015
From:	V Sreenivas Plant Licensing Branch II
To:	Mihaela Biro NRC/NRR/DRA
References
Download: ML15068A090 (3)

Text

NRR-PMDAPEm Resource From: Sreenivas, V Sent: Monday, March 09, 2015 8:54 AM To: Biro, Mihaela Cc: Reisifard, Mehdi

Subject:

RE: North Anna Units 1 and 2, Request for Information: TECHNICAL SPECIFICATION CHANGE PROPOSING PERMANENT FIFTEEN-YEAR TYPE A TEST INTERVAL As per our conference call, please find the following clarifications on the submitted RAI responses provided by the licensee letter dated Jan. 28, 2015:

Table B.1 of Attachment 5 to the LAR provides the list of findings from the 2013 peer review and provides an assessment of the impact on the ILRT extension application. In response to the request for additional information PRA RAI-1.a (ADAMS Accession No. ML15034A353) the licensee provided a list of F&Os and the associated SR, which did not meet Capability Category I requirements of the ASME/ANS RA-Sa-2009 PRA standard endorsed by RG 1.200, Revision 2.

a. The licensees disposition for F&Os IE-A6-01, DA-B2-01, DA-C14-01 and QU-B5-01 included in the response to PRA RAI-1.a states that the impact of each of these findings is expected to be bounded by an order of magnitude increase and that [t]he sensitivity study in of the LAR demonstrates that an order of magnitude increase in CDF or LERF does not impact acceptability of the results for this application. Justify how the cumulative effect of all of these open findings not meeting Capability Category I is acceptable for the ILRT extension application.

Response

The sensitivity study in Enclosure 1 of the proposed LAR demonstrated that an order of magnitude increase in core damage frequency (CDF) would not invalidate the results of the ILRT extension application. Although this sensitivity was referenced for individual Facts and Observations (F&Os), the sensitivity study is also considered bounding for the cumulative impact of the open findings. The F&Os which credited the bounding sensitivity study have been further evaluated using sensitivity studies, and their risk impact has been shown to be acceptable. The CDF and Large Early Release Frequency (LERF) increase for IE-A6-01 are 2E-8/yr and 1E-9/yr, respectively; for DA-B2-01 are 3E-9/yr and 3E-9/yr, respectively; for DA-C14-01 are 4E-8/yr and 1E-9/yr, respectively; and for QU-B5-01 are 1E-8/yr with no change in LERF. The bounding sensitivity in Enclosure 1 of the LAR considered the risk impact of an order of magnitude increase in CDF, or a CDF increase of 1.55E-5/yr. Although each of these F&Os was evaluated individually, their cumulative impact is not expected to exceed the increase in risk evaluated by the bounding sensitivity study. As a result, the cumulative effect of the open F&Os on the ILRT extension application is acceptable.

b. F&Os SY-A14-01, HR-G2-01, IFQU-A9-01, and IFSO-A4-01 were listed in Table B.1 of to the LAR but not in the response to PRA RAI-1.a. Requirements for Capability Categories I and II are the same for SRs related to those findings. If related SRs meet the requirements for Capability Category I (and II) of ASME/ANS RA-Sa-2009 PRA standard endorsed by RG 1.200, Revision 2, justify how those findings were resolved, as they were initially identified in Table B.1 of Attachment 5 to the LAR, or otherwise, justify how the cumulative effect of all of the F&Os (identified in parts a and b of this RAI) not meeting Capability Category I is acceptable for the ILRT extension application.

Response

1

F&Os SY-A14-01, HR-G2-01, IFQU-A9-01, and IFSO-A4-01 were listed in Table B.1 of Attachment 5 to the LAR because all of the F&Os from the peer review report were included in the LAR. The related Supporting Requirements (SRs) for these four F&Os were considered met in the peer review report. Consequently, they were not included in the response to PRA RAI-1.a, which requested only the SRs that did not meet Capability Category I requirements.

2

Hearing Identifier: NRR_PMDA Email Number: 1925 Mail Envelope Properties (V.Sreenivas@nrc.gov20150309085400)

Subject:

RE: North Anna Units 1 and 2, Request for Information: TECHNICAL SPECIFICATION CHANGE PROPOSING PERMANENT FIFTEEN-YEAR TYPE A TEST INTERVAL Sent Date: 3/9/2015 8:54:23 AM Received Date: 3/9/2015 8:54:00 AM From: Sreenivas, V Created By: V.Sreenivas@nrc.gov Recipients:

"Reisifard, Mehdi" <Mehdi.Reisifard@nrc.gov>

Tracking Status: None "Biro, Mihaela" <Mihaela.Biro@nrc.gov>

Tracking Status: None Post Office:

Files Size Date & Time MESSAGE 3632 3/9/2015 8:54:00 AM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: