ML103430423

Request for Additional Information Related to the Use of Nuetron Absorbing Inserts

ML103430423
Person / Time
Site:	LaSalle
Issue date:	12/10/2010
From:	Ellen Brown Plant Licensing Branch III
To:	Pacilio M Exelon Nuclear
Brown Eva, NRR/DORL, 415-2315
References
TAC ME2376, TAC ME2377
Download: ML103430423 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 10, 2010 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LASALLE COUNTY STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE USE OF NEUTRON ABSORBING INSERTS (TAC 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 (ADAMS) Package No. ML092810278), as supplemented in letters dated June 10 and November 23, 2010 (ADAMS Accession Nos.

ML101650229 and ML103270566, respectively), 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 December 8, 2010, it was agreed that a response would be provided within 30 days from the date of this letter.

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 by Araceli Billoch-Colon forI 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

REQUEST FOR ADDITIONAL INFORMATION NETCOINSERTS EXELON GENERATION COMPANY, LLC LASALLE COUNTY STATION, UNITS 1 AND 2 DOCKET NOS. 50-373 AND 50-374

1. On page 5 Attachment 1 to the supplement dated November 23, 2010 (Supplement), for the response to 3.a, confirm that "degradation" is thinning degradation. In addition, indicate the amount of areal density degradation that corresponds with each thinning degradation percentage (e.g., 57.5 percent, 79.8 percent, 68.1 percent, 65.3 percent, and 80 percent).

2. In Attachment 3 to the supplement, indicate the amount of areal density degradation that corresponds with each thinning degradation percentage (e.g., 52.27 percent, 29.97 percent).

3. On page 1 of Attachment 3 to the Supplement, it states:

... Unit 2 spent fuel storage rack cells are declared UNUSABLE when the RACKUFE projected degradation for the most limiting panel in a spent fuel pool cell exceeds 52.27 percent.

It appears that a BADGER result would also be a necessary criterion to declare the cell UNUSABLE. Clarify if a BADGER measurement was to exceed the allowable degradation thresholds and the RACKLIFE prediction did not, or whether that cell would be declared RESTRICTED or UNUSABLE.

4. On page 3 of Attachment 3 of the supplement, from the table entitled "Summary of BADGER Test Results," clarify the meaning of "loss." Address whether this is thinning degradation or areal density degradation. Discuss whether the "loss" is from nominal thickness or nominal area,l density or a different reference value.

5. As discussed on page 3 of Attachment 3 of the supplement, explain how panels G74 North and G74 South are "reference panels" since they are being irradiated and exhibit "loss." Also, describe the use of these "reference panels."

ENCLOSURE

ML101650229 and ML103270566, respectively), 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 December 8, 2010, it was agreed that a response would be provided within 30 days from the date of this letter.

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 by Araceli Billoch-Colon forI 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:

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DATE 12/10/10 12/10/10 12/10/10 12/10/10 12/10/10 1210/10 12/10110