ML113530044

Electronic Transmission, Draft Request for Additional Information Regarding Proposed Technical Specification Safety Limit Minimum Critical Power Ratio Changes

ML113530044
Person / Time
Site:	Limerick
Issue date:	12/19/2011
From:	Peter Bamford Plant Licensing Branch 1
To:	Chernoff H Plant Licensing Branch 1
Bamford, Peter J., NRR/DORL 415-2833
References
TAC ME7333
Download: ML113530044 (4)

Text

December 19, 2011 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:

LIMERICK GENERATING STATION, UNIT 1 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED TECHNICAL SPECIFICATION SAFETY LIMIT MINIMUM CRITICAL POWER RATIO CHANGES (TAC NO.

ME7333)

The attached draft request for additional information (RAI) was transmitted by electronic transmission on December 16, 2011, to Mr. Thomas Loomis, at Exelon Generation Company, LLC (Exelon). 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 submittal. The draft RAI is related to Exelons submittal dated October 12, 2011, regarding Limerick Generating Station, Unit 1, proposing to incorporate revised safety limit minimum critical power ratios into Technical Specification 2.1.

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 No. 50-352

Enclosure:

As stated

December 19, 2011 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:

LIMERICK GENERATING STATION, UNIT 1 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED TECHNICAL SPECIFICATION SAFETY LIMIT MINIMUM CRITICAL POWER RATIO CHANGES (TAC NO.

ME7333)

The attached draft request for additional information (RAI) was transmitted by electronic transmission on December 16, 2011, to Mr. Thomas Loomis, at Exelon Generation Company, LLC (Exelon). 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 submittal. The draft RAI is related to Exelons submittal dated October 12, 2011, regarding Limerick Generating Station, Unit 1, proposing to incorporate revised safety limit minimum critical power ratios into Technical Specification 2.1.

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 No. 50-352

Enclosure:

As stated DISTRIBUTION:

Public RidsNrrPMLimerick LPL1-2 R/F Accession No.: ML113530044 *via email OFFICE LPL1-2/PM DSS/SRXB NAME PBamford AUlses*

DATE 12/19/2011 12/16/2011 OFFICIAL RECORD COPY

DRAFT REQUEST FOR ADDITIONAL INFORMATION LIMERICK GENERATING STATION, UNIT 1 LICENSE AMENDMENT REQUEST REGARDING PROPOSED SAFETY LIMIT MINIMUM CRITICAL POWER RATIO CHANGE DOCKET NO. 50-352 By letter dated October 12, 2011 (Agencywide Documents Access and Management System Accession No. ML112870080), Exelon Generation Company, LLC (Exelon, the licensee) submitted a license amendment request (LAR) proposing to modify Technical Specification (TS) 2.1, Safety Limits, for Limerick Generating Station (LGS), Unit 1. The requested change involves revised Safety Limit Minimum Critical Power Ratios (SLMCPRs) calculated as a result of the cycle-specific analysis performed by Global Nuclear Fuel (GNF) to support operation in the upcoming LGS, Unit 1, Cycle 15. The Nuclear Regulatory Commission (NRC) staff has been reviewing the submittal and has determined that additional information is needed to complete its review.

1. In the LAR, Attachment 5, Tables RAI-06-1 and RAI-06-2, provide core maps to show those bundles experiencing 0.1% boiling transition criterion for limiting cases of single-loop operation (SLO) and two-loop operation (TLO). Please identify the bundle group and number of bundles in Figure 1 corresponding to their burnup status (once-burned, twice-burned, or fresh fuel) for Cycle 15.

2. Core design is an iterative process designed to develop an optimal configuration that meets operational requirements. In the LAR, Attachment 6, for the slides titled Preliminary Energy Utilization Plan for Limerick 1 Cycle 15 and Pre-Estimation -

Linear Reactivity, please provide the most current updated parameters applicable to LGS, Unit 1, Cycle 15.

3. GNF2 fuel deviates from traditional 10x10 design through the introduction of a new part length rod configuration, the use of higher linear power, and the use of mixing vanes. The staff considers this a new fuel design with regards to the four restrictions identified in the Safety Evaluation of General Electric (GE) Licensing Topical Reports NEDC-32601P, NEDC-32694 and Amendment 25 to NEDE-24011-P-A. Given that LGS, Unit 1 Cycle 15 uses a core loading pattern which includes GNF2 fuel, please provide the following: (1) an evaluation of the four restrictions in NEDC-32601P, NEDC-32694 and Amendment 25 to NEDE-24011-P-A, (2) a description that explains under what conditions the methodologies listed in Section 1.0 of Attachment 4 are applied to the LGS, Unit 1, Cycle 15 application, (3) the reason why GNF2 has much higher critical power uncertainty than that of GE14, as shown in Table 6 of Attachment 4, and (4) a clarification for the statement no new GNF fuel designs are being introduced in Limerick 1 Cycle 15 in Section 2.5 of Attachment 4.

Enclosure

DRAFT

4. In the LAR, Attachment 5, GNF Response to RAI Applied to LGS Unit 1, it states that LGS Unit 1 Cycle 15 is the first full reload of GNF2. Figure 1 of Attachment 4, indicates that Cycle 15 will contain both GE14 and GNF2 fuel. Please clarify the full reload statement against Figure 1.

5. Please identify the breakdown of the 10x10 data shown in Attachment 4, Figure 5, by fuel type (i.e. (GE14, GNF2), because Figure 5 only shows combined data points for the two fuel types.

6. Please clarify that there is no adverse impact relating to the GNF2 bent spacer wing operating experience to LGS, Unit 1, Cycle 15, operation. If there is an adverse impact, please provide an assessment of the impacts of such operation on fuel thermal performance.

7. Please provide an updated version of power/flow map for Cycle 15 operation including stability Option III features of scram region and controlled entry region based on the Boiling Water Reactor Owners Group position, as specified in NEDO-31960, for SLO and TLO.