ML15126A041

Request for Additional Information Regarding TSTF-425 License Amendment Request

ML15126A041
Person / Time
Site:	Calvert Cliffs
Issue date:	05/01/2015
From:	Flaherty M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML15126A041 (4)

Text

AMExelon Generation Mark D. Flaherty Plant Manager Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby. MD 20657 410 495 5205 Office 410 495 5444 Fax 443 534 5476 Mobile www.exeloncorp.com mark.flaherty@exeloncorp.com 10 CFR 50.90 May 1,2015 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-53 and DPR-69 NRC Docket Nos. 50-317 and 50-318

Subject:

Request for Additional Information Regarding TSTF-425 License Amendment Reauest

References:

1. Letter from G. H. Gellrich (Exelon) to Document Control Desk (NRC), dated May 1, 2014, License Amendment Request: Adoption of Technical Specification Task Force Traveler (TSTF) - 425, Revision 3, Relocate Surveillance Frequencies to Licensee Control - RITSTF Initiative 5b

2. Letter from N. S. Morgan (NRC) to G. H. Gellrich (Exelon), dated April 14, 2015, Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 - Request for Additional Information Regarding Technical Specification Task Force Traveler (TSTF) - 425, "Relocate Surveillance Frequencies to Licensee Control - RITSTF Initiative 5b," Revision 3 (TAC Nos. MF4065 and MF4066)

Reference 1 submitted a license amendment request to adopt TSTF-425. As part of their review, the Nuclear Regulatory Commission staff has requested additional information (Reference 2). Responses to the requested additional information are provided in Attachment (1).

This additional information does not change the No Significant Hazards Determination provided in Reference 1. No regulatory commitments are contained in this letter.

Should you have questions regarding this matter, please contact Mr. Larry D. Smith at (410) 495-5219.

A-wi RiL

Document Control Desk May 1,2015 Page 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on May 1, 2015.

Respectfully, Mark D. Flaherty Plant Manager MDF/PSF/bjm

Attachment:

(1) Request for Additional Information Regarding TSTF-425 cc: NRC Project Manager, Calvert Cliffs NRC Resident Inspector, Calvert Cliffs NRC Regional Administrator, Region I S. Gray, MD-DNR

ATTACHMENT (1)

REQUEST FOR ADDITIONAL INFORMATION REGARDING TSTF-425 Calvert Cliffs Nuclear Power Plant May 1, 2015

ATTACHMENT 1 REQUEST FOR ADDITIONAL INFORMATION REGARDING TSTF-425 By letter dated April 14, 2015, the Nuclear Regulatory Commission staff requested the following information to complete their review.

RAI-1

Step 8 of Section 4.0 of NEI 04-10, Revision 1 states, in part,that:

The risk impact of a proposed [Surveillance Test Interval (STI)] adjustment shall be calculated as a change of the test-limited risk (see Regulatory Guide 1.177, Section 2 .3.J 3 ]). Since the test-limited risk is associated with failures occurring between tests, the failure rate that shall be used in calculating the risk impact of a proposed STI adjustment is the time-related failure rate associated with failures occurring while the component is in standby between tests (i.e., risk associated with the longer time to detect standby-stress failures).

Describe how the Calvert Cliffs Surveillance Frequency Control Program will address the standby (i.e., the time-related)contribution for extended surveillances.

CCNPP RESPONSE TO RAI-1:

The standby time related failures will be assessed in accordance with NEI 04-10, Revision 1 by direct change in the test interval for those structures, systems, and components (SSCs) that include a standby periodically tested failure mode in the Calvert Cliffs probabilistic risk assessment (PRA) models along with the appropriate adjustments to common cause failure events. Where there is no standby periodically tested event in the PRA models and one is not added or the failure cannot be divided into time based and non-time based contributions, as allowed by Regulatory Guide 1.177 all contributors to the failure rate will be assumed to be time based and the values adjusted accordingly.

If the SSCs do not appear explicitly in the PRA models, either a bounding assessment using a surrogate event or a qualitative assessment will be performed in accordance with the NEI 04-10, Revision 1, guidance.

RAI-2: of the LAR states that Calvert Cliffs does not have a low power or shutdown probabilisticrisk assessment model. A qualitative analysis of shutdown events is acceptable,as presented in the NRG-endorsed document NEI 04-10, Revision 1. Step 10 of Section 4.0 of NEI 04-10, Revision 1 provides guidance on the initial assessment of Internal Events, External Events, and Shutdown Events. Describe how shutdown events will be assessed as part of the Calvert Cliffs Surveillance Frequency Control Program.

CCNPP RESPONSE TO RAI-2:

While Calvert Cliffs does not have a low power or shutdown PRA model, the Surveillance Frequency Control Program will assess shutdown events qualitatively per NEI 04-10, Revision 1 guidance as incorporated in Exelon procedures.

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