ML090300452

Electronic Transmission, Draft Request for Additional Information Regarding Proposed Technical Specification Changes to Reflect Steam Generator Replacement

ML090300452
Person / Time
Site:	Three Mile Island
Issue date:	02/10/2009
From:	Peter Bamford Plant Licensing Branch 1
To:	Chernoff H Plant Licensing Branch 1
Bamford, Peter J., NRR/DORL 415-2833
References
Download: ML090300452 (3)

Text

February 10, 2009 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM: Peter Bamford, Project Manager /ra/

Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

THREE MILE ISLAND, UNIT NO. 1 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED TECHNICAL SPECIFICAITON CHANGES TO REFLECT STEAM GENERATOR REPLACEMENT The attached draft request for additional information (RAI) was transmitted by electronic transmission on February xx, 2009 to Ms. Wendi Croft, at Exelon Generation Company, LLC (Exelon, the licensee). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call (if needed) with Exelon in order to clarify the licensees amendment request regarding technical specification changes to reflect steam generator replacement. The draft RAI is related to the licensees submittal dated October 9, 2008. The draft questions were sent to ensure that they were understandable, the regulatory basis was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow Exelon to evaluate and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.

Docket Nos. 50-289

Enclosure:

As stated

February 10, 2009 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM: Peter Bamford, Project Manager /ra/

Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

THREE MILE ISLAND, UNIT NO. 1 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED TECHNICAL SPECIFICAITON CHANGES TO REFLECT STEAM GENERATOR REPLACEMENT The attached draft request for additional information (RAI) was transmitted by electronic transmission on February xx, 2009 to Ms. Wendi Croft, at Exelon Generation Company, LLC (Exelon, the licensee). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call (if needed) with Exelon in order to clarify the licensees amendment request regarding technical specification changes to reflect steam generator replacement. The draft RAI is related to the licensees submittal dated October 9, 2008. The draft questions were sent to ensure that they were understandable, the regulatory basis was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow Exelon to evaluate and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.

Docket Nos. 50-289

Enclosure:

As stated DISTRIBUTION:

Public RidsNrrPMPBamford LPL1-2 R/F Accession No.: ML09 *via correspondence OFFICE LPL1-2/PM CSGB/BC NAME PBamford AHiser*

DATE 2/10/09 01/16/2009 OFFICIAL RECORD COPY

REQUEST FOR ADDITIONAL INFORMATION THREE MILE ISLAND, UNIT 1 REPLACEMENT STEAM GENERATOR LICENSE AMENDMENT DOCKET NO. 50-289 By letter dated October 9, 2008, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML082890539), AmerGen Energy Company, LLC (the licensee, now Exelon Generation Company, LLC) submitted a license amendment request regarding proposed changes to the technical specifications (TSs) to reflect steam generator (SG) replacement for Three Mile Island Nuclear Station, Unit 1 (TMI-1). The Nuclear Regulatory Commission staff has been reviewing the submittal and has determined that additional information is needed to complete its review.

1. Please confirm that the 40 percent throughwall tube repair criterion remains acceptable for the replacement SGs and discuss how it was determined (e.g., was it determined in accordance with Regulatory Guide 1.121, Bases for Plugging Degraded PWR

[pressurized water reactor] Steam Generator Tubes).

2. For the replacement SGs, please provide the tube size (diameter and wall thickness) and the design differential pressure across the tubes during normal operation.

3. You have proposed to increase your technical specification limit on primary-to-secondary leakage to 150 gallons per day per steam generator. In addition, you have indicated that your Bases would be modified accordingly. Your current TS 6.19(b)(2) indicates that the safety analysis assumes a leakage volume or rate of primary-to-secondary leakage from all steam generators depending on the specific accident analyses. The limit on primary-to-secondary leakage is primarily based on two considerations: (1) limit the frequency of tube rupture and (2) limit the radiological dose to the public and control room operators.

Given the current wording in TS 6.19(b)(2), which implies that at least one accident analyses assumes a leakage volume, please confirm that your current NRC approved design and licensing basis accident analyses that assume primary to secondary leakage (e.g., steam line break, locked rotor, control rod ejection, etc.) assume that at least 150 gallons per day primary-to-secondary leakage is occurring in each steam generator (i.e.,

they are based on a leakage rate of 150 gallons per day). In addition, please provide the reference that modified your design and licensing basis to reflect the increase to 150 gallons per day primary-to-secondary leakage.