ML14323A021

Requests for Additional Information for the Review of the Sequoyah Nuclear Plant, Units 1 and 2, License Renewal Application - Set 23

ML14323A021
Person / Time
Site:	Sequoyah
Issue date:	12/04/2014
From:	Sayoc E License Renewal Projects Branch 1
To:	James Shea Tennessee Valley Authority
Sayoc E, NRR/DLR/RPB1, 301-415-4084
References
TAC MF0481, TAC MF0482
Download: ML14323A021 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 4, 2014 Mr. Joe W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority P.O. Box 2000 Soddy-Daisy, TN 37384

SUBJECT:

REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION - SET 23 (TAC NOS. MF0481 AND MF0482)

Dear Mr. Shea:

By letter dated January 7, 2013, Tennessee Valley Authority submitted an application pursuant to Title 10 of the Code of Federal Regulations (CFR) Part 54, to renew operating licenses DPR-77 and DPR-79 for Sequoyah Nuclear Plant, Units 1 and 2, for review by the U.S. Nuclear Regulatory Commission staff. The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review.

These requests for additional information were discussed with Henry Lee, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me at 301-415-4084 or by e-mail at Emmanuel.Sayoc@nrc.gov.

Sincerely,

/RA/

Emmanuel Sayoc, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328

Enclosure:

Requests for Additional Information cc w/encl: Listserv

ML14323A021

• concurred via email OFFICE LA:DLR/RPB1*

PM:DLR/RPB1 BC:DLR/RPB1 PM:DLR/RPB1 NAME YEdmonds ESayoc YDiaz-Sanabria ESayoc DATE 11/24/14 12/1/14 12/4/14 12/4/14

SUBJECT:

REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION - SET 23 (TAC NOS. MF0481 AND MF0482)

DISTRIBUTION:

HARD COPY:

DLR R/F E-MAIL:

PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRpb2 Resource RidsNrrDlrRerb Resource RidsNrrDlrRarb Resource RidsNrrDlrRasb Resource beth.mizuno@nrc.gov brian.harris@nrc.gov john.pelchat@nrc.gov gena.woodruff@nrc.gov siva.lingam@nrc.gov wesley.deschaine@nrc.gov galen.smith@nrc.gov scott.shaeffer@nrc.gov jeffrey.hamman@nrc.gov craig.kontz@nrc.gov caudle.julian@nrc.gov generette.lloyd@epa.gov gmadkins@tva.gov clwilson@tva.gov hlee0@tva.gov dllundy@tva.gov

ENCLOSURE SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION SUPPLEMENTAL REQUESTS FOR ADDITIONAL INFORMATION RAI B.1.34-9d (Follow up)

Background:

By letter dated October 22, 2014, the applicant provided its response to the staffs Request for Additional Information (RAI) B.1.34-9c related to the applicants plant specific fluence evaluations for the upper core plates at Sequoyah (SQN) Units 1 and 2 for the components that are located above the upper core plates. This response included the methodology used to perform these evaluations as well as the projected fluence values for the upper core plate and above the upper core plate.

Additional background information for Part 1 of this RAI: As stated in the response, the discussion on fluence methodology beginning on Page 2 of Enclosure 1 to the response letter indicates that the transport methods described in WCAP-14040-A, and WCAP-16083-NP-A were used to calculate fluence values for locations above the upper core plate. The response indicates that the (r,z) transport model was updated to include information specific to regions directly above the active fuel stack for SQN-1.

Additional background information for Part 2 of this RAI: As stated in the response, the discussion on upper core plate neutron fluence values, beginning on Page 3 of Enclosure 1 to the response letter, indicates that the fluence value is 1.87E21 n/cm2 for the lower surface of the upper core plat for SQN Unit 1. Note that reactor vessel fluence methods are permitted a 20-percent margin for accuracy because the formulae for performing adjusted reference temperature (ART) margin term adjustments include 20-percent margins for the fluence terms used in the ART calculations.

Issue:

The fluence calculations provided by the applicant in its letter of October 22, 2014, provide the projected fluence values for SQN Units 1 and 2, but do not provide specific locations for the reported values, nor the projected values include any uncertainty or margin of accuracy, nor if the chosen methodology is qualified for estimating fluence values at the upper core plate location.

Request:

1. For SQN Units 1 and 2:

(a) Indicate the radial location of the peak estimated fluence values for the upper core plate.

(b) Provide graphics to compare the prior and current (r,z) models.

(c) Show that the current (r,z) spatial representation is sufficiently refined.

(d) Provide information to verify that the detail represented in the (r,) model is adequate and produces a reliable fluence estimate. Specifically, Regulatory Guide (RG) 1.190 permits representation of internal fuel assemblies in considerably less detail than peripheral assemblies, particularly because the contribution of fuel, at the core periphery, to the vessel flux is most significant. This is not the case for the upper core plate.

(e) Provide information to indicate that the chosen fluence methods are qualified for estimating fluence at the upper core plate location.

2. For SQN Unit 1: explain whether the neutron fluence value reported for the lower surface of the upper core plate of SQN Unit 1 (i.e., 1.87 x 1017 n/cm2 [E > 1.0 MeV]) has been augmented to account for any uncertainty associated with the calculative methods, nuclear data, or modeling accuracy.