ML14170B010

Request for Additional Information

ML14170B010
Person / Time
Site:	Hatch
Issue date:	06/23/2014
From:	Martin R Plant Licensing Branch II
To:	Pierce C Southern Nuclear Operating Co
Martin R
References
TAC MF3374, TAC MF3375
Download: ML14170B010 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 23, 2014 Mr. C. R. Pierce Regulatory Affairs Director Southern Nuclear Operating Company, Inc.

Post Office Box 1295, Bin- 038 Birmingham, AL 35201-1295

SUBJECT:

HATCH NUCLEAR PLANT, UNITS 1 AND 2- REQUEST FOR ADDITIONAL INFORMATION (TAC NOS. MF3374 AND MF3375)

Dear Mr. Pierce:

By letter dated January 16, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14016A202) Southern Nuclear Operating Company (SNC),

licensee of Edwin I. Hatch Nuclear Plant (HNP), Units 1 and 2, submitted a license amendment request (LAR) to modify the Technical Specifications (TSs) for HNP. The requested amendment will revise the existing HNP TS 3.7.5, Control Room Air Conditioning (AC) System, to provide new Required Actions for one, two, or three main control room (MCR) AC subsystems inoperable, and make other required corresponding changes.

The LAR indicates that the changes requested are at least in some part similar to those of TSTF-477. The MCR AC subsystem is comprised of three 50 percent capacity trains rather than the two 100 percent trains that the Technical Specification Task Force (TSTF) directly addresses. The TSTF indicated required action completion time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to recover from a no trains operable status to a one-train operable status appears analogous. However, since each train of AC at HNP is 50 percent of the required design capability instead of 100 percent, the completion time to restore a second train to operability of 7 days is beyond the TSTF for a boiling-water reactor/4 plant. The fact that 50 percent rather than zero percent capability would exist suggests that for some wider range of ambient environmental conditions the needed AC capability would very likely be present. The existing HNP TS established this limit as 65 degrees Fahrenheit (°F) or less ambient temperature for an extended period (previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />). The proposed control room air temperature limit of 90 °F or less is based in part on ensuring control rod (CR) panel temperatures would not exceed the 105 oF equipment qualification temperature, similar to the existing 65 oF ambient temperature limit. However, the existing 65 oF limit for ambient temperature would appear to have some inherent additional margin given that the associated temperatures of cooling water for AC condensers and fresh air intake would likely allow CR temperature to be kept well below 90 °F.

1. What is being gained or avoided (benefit) by having a CR temperature limit of 90 oF versus an ambient temperature limit of 65 °F?

2. What would be the safety impact of operating for 7 days with a CR temperature at 90 oF versus the current ambient 65 oF limit?

C. R. Pierce The NRC staff finds that additional information is needed as set forth in the Enclosure. Please provide the additional information within thirty (30) days of the date of this letter.

Sincerely, 0 A/./J f-/)J~

f/ R';b~art(n, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366 cc w/encl: Distribution via Listserv

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C. R. Pierce The NRC staff finds that additional information is needed as set forth in the Enclosure. Please provide the additional information within thirty (30) days of the date of this letter.

Sincerely,

/RAJ Robert E. Martin, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366 cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC LPL2-1 R/F Rtorres, NRR

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