ML081560649

Response to NRC Request Concerning Unresolved Item 05000454/2008008 and 05000455/2008008

ML081560649
Person / Time
Site:	Byron
Issue date:	06/04/2008
From:	Hoots D M Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BYRON 2008-0054, IR-08-008
Download: ML081560649 (2)

See also: IR 05000454/2008008

Text

Nuclear June 4,2008 LTR: BY RON 2008-0054

File: 2.01.0700

United States Nuclear Regulatory

Commission

Attention:

Document Control Desk Washington, DC 20555-0001

Byron Station, Unit

1 and Unit 2 Facility Operating License Nos. NPF-

37 and NPF-66 NRC Docket Nos. STN

50-454 and STN 50-455 Subject: Response to NRC Request Concerning Unresolved

Item 0500045412008008

and0500045512008008 Reference: Letter from

Ann Marie Stone (USNRC) to Charles

G. Pardee (Exelon Generation Company, LLC), "Byron Station, Units 1 and 2 Follow Up

Inspection

of an Unresolved

ltem (URI) 0500045412008008;

05000455/2008008," dated May 5,2008 In the referenced letter, the NRC requested

a response within 30 days with our

proposed actions and schedule to resolve the noncompliance

of the single failure assumptions used in

our Ultimate Heat Sink (UHS) design basis analysis.

To achieve compliance, a design basis re-analysis

of the UHS is being performed

to evaluate the impact of postulated

passive electrical single failures.

The results of this analysis will be incorporated

into the Byron Station design basis

via requirements

of 10 CFR 50.59, "Changes, tests, and experiments.'This

is expected to be completed

by December 5, 2008. We do not anticipate

any physical modifications

to the UHS will be necessary.

In the interim, we have invoked the provisions

of Administrative Letter

98-1 0, "'Dispostioning

of Technical Specifications

That are insufficient

to Assure Plant Safety.'" We have concluded

that the UHS remains operable with administrative controls

in place to ensure seven of the eight UHS cooling cells are operable to

be within the Limiting Condition

for Operations

for Technical Specifications 3.8.9, "Ultimate Heat

Sink.'" These interim controls will remain

in place until the design basis for the UHS is revised.

June 4,2008 U.S. Nuclear Regulatory Commission

Page 2 There are no regulatory commitments associated with this response. Should you have any questions about

this letter, please contact Mr. William Grundmann at (81 5) 406- 2800. Respectfully, David M. Hoots Site Vice President Byron Station

cc: Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - Byron Station

Director, Office of Enforcement