ML070720702

E-mail, Miller, NRR, to Distel, Exelon, Clarification of Control Room Habitability RAI Response

ML070720702
Person / Time
Site:	Oyster Creek
Issue date:	03/13/2007
From:	Geoffrey Miller Plant Licensing Branch III-2
To:	Distel D Exelon Corp
References
GL-03-001
Download: ML070720702 (2)

Text

From: Ed Miller To: david.distel@exeloncorp.com Date: 03/13/2007 3:46:25 PM

Subject:

Questions regarding GL2003-01

Dave, As discussed, the following are the clarifications needed regarding the original questions on the Oyster Creek GL 2003-01 RAI Response. They are being provided via e-mail to allow you to review them and agree on a response schedule. They do not represent a formal request for information or an NRC staff position.

G. Edward Miller Project Manager Division of Operating Reactor Licensing U.S. Nuclear Regulatory Commission (301) 415-2481 In response to a Request for Additional Information (RAI) regarding NRC Generic Letter 2003-01 "Control Room Habitability", dated September 14, 2005 (ADAMS Accession No. ML052370260) regarding Oyster Creek Nuclear Generating Station (OCNGS), AmerGen Energy Company, LLC, submitted additional information for OCNGS in a letter dated November 17, 2005 (ADAMS Accession No. ML053220138).

The RAI requested a description of the test and measurements that have been performed to demonstrate that the inleakage characteristics of the control room envelope, including its walls, floors and ceilings, are consistent with the OCNGS licensing basis. It also requested a description of how it has been determined that the byproducts of a fire or the inadvertent actuations of a fire suppression system will not propagate such that reactor control would be unattainable from either the control room and the alternate shutdown panels. In the RAI the staff also communicated their belief that an additional technical specification to measure control room ventilation system makeup and recirculation flowrates is necessary to confirm compliance with OCNGS's licensing basis.

Regarding the response:

1. In Enclosure 1, Page 2, Paragraph 2 (below the table), AmerGen states that "Outside air from the Control Room HVAC System air intake contains the highest radioactivity concentration of any potential inleakage source to the Oyster Creek CRE. " But in Enclosure 1, Page 3, Paragraph 4, AmerGen states that ".the Upper Cable Spreading Room (UCSR) is the only possible source of radioactivity inleakage at concentrations higher than that found in the CRE air intake." Please clarify the statements about the outside air and the air within the UCSR both having the higher or highest radioactivity concentration.

2. In Enclosure 1, Page 3, Paragraph 5, AmerGen states that "No inleakage is expected from these sources (fire doors, fire penetrations in the UCSR) since no differential pressure will exist that will drive inleakage into the UCSR." In Enclosure 1, Page 2, Paragraph 3, AmerGen states that "The majority of the control room ventilation system ductwork under negative pressure is in the UCSR adjacent to the CRE." Previously, the NRC staff has held the position that, should there be inleakage from the UCSR into the CRE ventilation system ductwork there, it would appear logical to assume that the pressure in the UCSR would drop creating a differential pressure situation that would drive inleakage into the UCSR. Please provide additional information supporting the contention that there could not be any air leakage into the CRE ventilation duct from the UCSR atmosphere to result in a lowering of the UCSR pressure relative to surrounding areas.

Mail Envelope Properties (45F6FF91.518 : 9 : 35080)

Subject:

Questions regarding GL2003-01 Creation Date 03/13/2007 3:46:25 PM From: Ed Miller Created By: GXM@nrc.gov Recipients Action Date & Time exeloncorp.com Transferred 03/13/2007 3:46:38 PM david.distel (david.distel@exeloncorp.com)

Post Office Delivered Route exeloncorp.com Files Size Date & Time MESSAGE 3922 03/13/2007 3:46:25 PM TEXT.htm 6507 Options Auto Delete: No Expiration Date: None Notify Recipients: Yes Priority: Standard ReplyRequested: No Return Notification: None Concealed

Subject:

No Security: Standard To Be Delivered: Immediate Status Tracking: Delivered & Opened