ML103210499

Request for Additional Information, Related to the Use of Neutron Absorbing Inserts

ML103210499
Person / Time
Site:	LaSalle
Issue date:	11/19/2010
From:	Ellen Brown Plant Licensing Branch III
To:	Pacilio M Exelon Nuclear
Brown Eva, NRR/DORL, 415-2315
References
TAC ME2376, TAC ME2377
Download: ML103210499 (5)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C.

November 19, 2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555 LASALLE COUNTY STATION, UNITS 1 AND 2 -REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE USE OF NEUTRON ABSORBING INSERTS (T AC NOS. ME2376 AND ME2377)

Dear Mr. Pacilio:

By letter to the Nuclear Regulatory Commission (NRC) dated October 5, 2009 (Agencywide Documents Access and Management Systems Package No. ML092810278),as supplemented in a letter dated June 10, 2010 (ADAMS Accession No. ML101650229), Exelon Generation Company, LLC submitted a request to revise Technical Specification (TS) Section 4.3.1, "Criticality," to address a non-conservative TS, for the LaSalle County Station, Units 1 and 2. The proposed change addresses the Boraflex degradation issue in the Unit 2 spent fuel storage racks by revising TS Section 4.3.1 to allow the use of NETCO-SNAP-IN rack inserts in Unit 2 spent fuel storage rack cells as a replacement for the neutron absorbing properties of the existing Boraflex panels. The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with Mr. Ken Nicely of your staff on November 19, 2010, it was agreed that a response would be provided within 30 days from the date of this letter.

M. Pacilio -Please note that if you do not respond to this letter within the prescribed response time, or provide an acceptable alternate date in writing, we may reject your application for amendment under the provisions of 10 CFR Section 2.108. Should you need to contact me, I can be reached at (301) 415-2315.

Sincerely, IRA! Eva A. Brown, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and Request for Additional cc w/encl: Distribution via Listserv REQUEST FOR ADDITIONAL INFORMATION NETCOINSERTS EXELON GENERATION COMPANY, LLC LASALLE COUNTY STATION, UNITS 1 AND 2 DOCKET NOS. 50-373 AND 50-374 Technical Specification (TS) 4.3.1.a states: "keff s 0.95 if fully flooded with unborated water, which includes an allowance for uncertainties as described in Section 9.1.2 of the UFSAR; ... " Explain the controls that exist or that will be developed so that recent and proposed changes to Updated Final Safety Analysis Report Section 9.1.2 and associated analyses will be comprehensively evaluated to ensure that such changes do not challenge the inputs, assumptions, and methods, which form the bases for this license amendment request. Identify the major parameters, values, uncertainties and/or assumptions in the criticality analysis that ensures that keff s 0.95 if fully flooded with unborated water. Provide a list of those analyses/calculations which were used to establish compliance with the requirements of 10 CFR 50.68(b)(4). Section 4.3.1 of NUREG-1433, "Standard Technical Specifications, General Electric Plants, BWRl4," includes a description of the assembly maximum U-235 enrichment limit. Address why a similar limit was not included with the proposed change. The current license amendment request indicates the NETCO-SNAP-IN rack inserts will not be installed in all useable storage cells until 2016. In the interim, the licensee will continue to credit BORAFLEXTM in those storage modules that do not have SNAP-IN rack inserts. Some of the cells for which the licensee intends to continue crediting BORAFLEXTM and fuel assemblies have degraded below the minimum B-10 areal density of 0.020 gm/cm used in the analysis of record as described in the June 15,1989, safety evaluation (ADAMS Accession No. ML021140183).

With respect to the crediting of degraded BORAFLEXTM, provide the following information: A description of the nuclear criticality safety analysis performed to demonstrate the acceptability of storing fuel in cells with BORAFLEX Ž below the a B-10 areal density of 0.020 gm/cm 2; A description of the measures to be used to account for unknowns or uncertainties in a. above; and A description of the measures to prevent a misloading during fuel handling or a justification explaining why the consequences of such an event would be acceptable.

' Section 50.36( c)(4 ) to Title 10 of the Code of Federal Regulations, requires that the Design Features section of the TS shall include" ... features of the facility such as materials of construction and geometric arrangements, which, if altered or modified, would have a significant effect on safety and are not covered in categories described in paragraphs (c) (1), (2), and (3) of this section." Given LaSalle's plans to rely on the 8-10 content of the rack inserts in the Unit 2 spent fuel pool, provide a description of those administrative controls that will be put in place to ensure that 8-10 content of the NETCO-SNAP-IN rack inserts will be consistent with what is assumed in the rack inserts and analyses.

M. Pacilio Please note that if you do not respond to this letter within the prescribed response time, or provide an acceptable alternate date in writing, we may reject your application for amendment under the provisions of 10 CFR Section 2.108. Should you need to contact me, I can be reached at (301) 415-2315.

Sincerely, IRA! Eva A. Brown, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-373 and 50-374

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC LPL3-2 RlF RidsNrrPMLaSalie Resource RidsNrrLA THarris Resource RidsOgcRp Resource RidsRgn3MailCenter Resource RidsAcrsAcnw_MailCTR Resource ADAMS Accession No ML103210499 NRR-088 RidsNrrDorlLpl3-2 Resource RidsNrrDorlDpr Resource ABiloch, NRR *via email dated OFFICE LPL3-2/PM LPL3-2/LA SRXB/BC LPL3-2/BC LPL3-2/PM NAME EBrown THarris AUlses* RCarlson EBrown DATE 11/18/10 11/18/10 11/18/10 11/19/10 11/19/10 OFFICIAL RECORD