ML14050A081

Correction to Request for Additional Information B.2.1.10-1, Letter Dated February 7, 2014, for the Review of the Byron Station and Braidwood Station, Units 1 and 2, LRA Set 13

ML14050A081
Person / Time
Site:	Byron, Braidwood
Issue date:	03/07/2014
From:	Robinson L License Renewal Projects Branch 1
To:	Gallagher M Exelon Generation Co
Robinson L, 415-4115
References
TAC MF1879, TAC MF1880, TAC MF1881, TAC MF1882
Download: ML14050A081 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 7, 2014 Mr. Michael P. Gallagher Vice President, License Renewal Projects Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348

SUBJECT:

CORRECTION TO REQUEST FOR ADDITIONAL INFORMATION B.2.1.10-1, LETTER DATED FEBRUARY 7, 2014, FOR THE REVIEW OF THE BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION, SET 13 (TAC NOS. MF1879, MF1880, MF1881, AND MF1882)

Dear Mr. Gallagher:

By letter dated May 29, 2013, Exelon Generation Company, LLC, submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54, to renew the operating licenses NPF~37, NPF-66, NPF-72, and NPF-77 for Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2, respectively, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff).

The staff issued a request for additional information (RAI) dated February 7, 2014 (ML14023A564). In reviewing the RAI, the staff identified missing information as stated in the Enclosure. We regret any inconvenience this may have caused.

If you have any questions regarding this matter, please contact me at 301-415-4115 or e-mail Lindsay.Robinson@nrc.gov.

lindsay R Robinson, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-454, 50-455, 50-456, and 50-457

Enclosure:

Corrected Request for Additional Information page cc: Listserv

• ML14050A081 *concurred via email OFFICE LA:DLR PM: RPB1 :DLR PM:RPB1 :DLR BC:RPB1 :DLR PM:RPB1:DLR NAME YEdmonds LRobinson JDaily YDiazSanabria LRobinson DATE 3/6/14 3/6/14 3/6/14 3/6/14 3/7/14

Background:

Both Byron and Braidwood have operating experience where the coupon tree holding the Boral sample coupons was not surrounded by freshly discharged fuel in accordance with the original equipment manufacturer's recommendations.

Issue:

In order to have an effective coupon monitoring program, the coupons should be the leading indicators of material degradation as compared to the neutron absorber material in the spent fuel storage racks. That is, the dose received and/or long-term exposure to the wet pool environment by the coupons should be bounding of the material in the racks. Allowing the coupons to lead the neutron absorber material in the racks provides reasonable assurance that the applicant will detect any material degradation in the coupons before the material in the spent fuel pool racks starts to degrade.

Request:

Please discuss how the coupon exposure (i.e., coupon tree location) will provide reasonable assurance that Bora I degradation is identified prior to potential loss of neutron-absorbing capability of the material in the spent fuel racks. If the coupon exposure to the environment is not bounding of the material in the racks, discuss how the aging effects of the Bora I material will be managed for the unbounded racks.

RAI 8.2.1.10-1 Applicability:

Byron and Braidwood

Background:

LRA Section 8.2.1.10 Enhancement 1 provides three options the applicant may take to disposition potential primary water stress corrosion cracking (PWSCC) of the Byron and Braidwood Units 1 and 2 steam generator divider plate welds to the primary head and tubesheet cladding. The second option for Enhancement 1 indicates that an analytical evaluation will be performed to establish a technical basis to disposition the potential degradation mechanism.

Option 2: Analysis Perform an analytical evaluation of the steam generator divider plate welds in order to establish a technical basis which concludes that the steam generator reactor coolant pressure boundary is adequately maintained with the presence of steam generator divider plate weld cracking. The analytical evaluation will be submitted to the NRC for review and approval prior to entering associated PEO.

In addition, LRA Section 8.2.1.10 Enhancement 2 provides three options the applicant may take to disposition potential PWSCC of the Byron and Braidwood Unit 1 steam generator tube-to-tubesheet welds. The second and third options for Enhancement 2 indicate that an analytical evaluation will be performed to determine that the steam generator tube-to-tubesheet welds are not susceptible to PWSCC or that the reactor coolant pressure boundary will be redefined where the steam generator tube-to-tubesheet welds are not required.

Letter toM P. Gallagher from Lindsay R. Robinson dated March 7, 2014

SUBJECT:

CORRECTION TO REQUEST FOR ADDITIONAL INFORMATION B.2.1.1 0-1, LEDER DATED FEBRUARY 7, 2014, FOR THE REVIEW OF THE BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION, SET 13 (TAG NOS. MF1879, MF1880, MF1881, AND MF1882)

DISTRIBUTION EMAIL:

PUBLIC RidsNrrDir Resource RidsNrrDirRpb1 Resource RidsNrrDirRasb Resource RidsOgcMaiiCenter RidsNrrPMByron Resource RidsNrrPMBraidwood Resource LRobinson JDaily DMclntyre, OPA EDuncan, Rill JBenjam1n, Rill AGarmoe, Rill JMcGhee, Rill JRobbins, Rill VMitlyng, Rill PChandrathil, Rill