ML15231A585

2015/08/18 NRR E-mail Capture - [External_Sender] Information Requested to Support Closeout of NAPS CAL Item #9

ML15231A585
Person / Time
Site:	North Anna
Issue date:	08/18/2015
From:	Aitken D E Dominion Generation
To:	V Sreenivas Plant Licensing Branch II
References
Download: ML15231A585 (4)

Text

1 NRR-PMDAPEm Resource From: Diane Aitken (Generation - 6) [diane.aitken@dom.com]

Sent: Tuesday, August 18, 2015 3:57 PM To: Sreenivas, V

Subject:

[External_Sender] Information requested to support closeout of NAPS CAL Item #9 Attachments:

image001.gifV, Below is the information regarding CAL Item

1. 9 that was discussed today during our 1:30 pm call. Please let me know if further information is need to close this CAL Item.

Thanks - Diane

CAL Item Number 9 - Time-Limiting Aging Analyses (TLAA) - Clarification in response to NRC Request of August 18, 2015:

The components reviewed in detail for TLAA are identified in Attachment 2 of Dominion Letter Serial No.13-143. Resulting moments at several locations (nodes) of the math models of each of these components from the results of dynamic analyses from the Mineral VA earthquake of August 23, 2011 were tabulated and compared to the previously calculated moments from North Anna's OBE. For th e majority of locations, the ratio of moments between the August 23, 2011 event and the OBE was less than unity.

At some locations, the ratio was larger than unity and these locations were reviewed in detail. These reviews can be described as follows:

(a) At some locations, the previously calculated cumulative usage factor (CUF) was extremely small thus there was ample margin to accommodate the small increase in the seismic stress. An example is a 6" hot leg safety injection branch line where the ratio of the resulting moments was 1.22, but the previous CUF was only 0.03, thus the increase was considered acceptable. (b) At some locations, Westinghouse generic OBE loads were used in the previous analyses, which provided a significant margin. An example is the inlet nozzle of reactor coolant pump where the Westinghouse OBE moment was 20180 in-kip, compared to 7606 in-kip from the Mineral event of August 23, 2011. Another example is a 2" branch line CVCS Loop Fill connection to Cross-over leg, where the ratio of the moments was 1.56, however, the branch line was qualified using significantly higher seismic loads per WCAP-8914, Vol. 1&2, thus no fatigue concern existed at this location. (c) At some locations, the CUF was primarily governed by thermal transients at the gross discontinuity and not by the seismic loading. Therefore, marginal increases in seismic moment were considered acceptable. An example is the Low Head Safety Injection branch line where the ratio of the moments was 1.23; the CUF was 0.07, which was primarily due to thermal transients.

It should also be noted that the strong motion durations of the Mineral earthquake of August 23, 2011 ranged from 1 to 3 second in the three or ientations, thus producing only a small number of alternating stress cycles. In summary, the August 23, 2011 earthquake had an insignificant effect on the component fatigue and previous TLAAs.

2

Diane E. Aitken Dominion Corporate Licensing

Innsbrook Technical Center, 2SE

804-273-2694 office 804-310-6552 cell diane.aitken@dom.com Please consider the environmen t before printing this e-mail.

CONFIDENTIALITY NOTICE: This electronic message contains information which may be legally confidential and or privileged and does not in any case represent a firm ENERGY COMM ODITY bid or offer relating thereto which binds the sender without an additional express written confirmation to that effect. The information is intended solely for the individual or entity named above and access by anyone else is unauthorized. If you are not the intended recipient, any di sclosure, copying, distribution, or use of the contents of this information is prohibited and may be unlawful. If you have received this electronic transmission in error, please reply immediately to the sender that you have received the message in error, and delete it. Thank you.

Hearing Identifier: NRR_PMDA Email Number: 2312 Mail Envelope Properties (CE3101AB4F73E84F9E63541CBF61CFC10111F1A8)

Subject:

[External_Sender] Information requeste d to support closeout of NAPS CAL Item

1. 9 Sent Date: 8/18/2015 3:56:48 PM Received Date: 8/18/2015 3:56:52 PM From: Diane Aitken (Generation - 6)

Created By: diane.aitken@dom.com Recipients: "Sreenivas, V" <V.Sreenivas@nrc.gov> Tracking Status: None

Post Office: INBE10W803.mbu.ad.dominionnet.com Files Size Date & Time MESSAGE 3716 8/18/2015 3:56:52 PM image001.gif 351

Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

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