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{{#Wiki_filter:1 Burkhardt, Janet From:Wilkins, Lynnea Sent: Friday, September 20, 2013 10:08 AM To: Van Der Kamp, David (dwvande@nppd.com)
{{#Wiki_filter:Burkhardt, Janet From:                             Wilkins, Lynnea Sent:                             Friday, September 20, 2013 10:08 AM To:                               Van Der Kamp, David (dwvande@nppd.com)
Cc: Burkhardt, Janet
Cc:                               Burkhardt, Janet


==Subject:==
==Subject:==
Cooper - Request for Additional Informatio n Regarding Core Plate Hold Down Bolt Stress Analysis (ME9550)Dave, By letter dated January 16, 2012 (ADAMS Accession No. ML12031A249), the Nebraska Public Power District (NPPD or the licensee), submitted a report on the stress analysis of the Cooper Nuclear Station (CNS) core plate rim bolts. This report was submitted in accordance with License Renewal Commitment NLS2009100-1, as documented in NUREG-1944, whereby the licensee committed to perform an analysis of the CNS core plate rim bolts to demonstrate the adequacy of the bolts considering the loss of bolt pre-load experienced during the period of extended operation (PEO) and submit this analysis at least two years prior to entering the PEO. By letter dated May 24, 2013 (ADAMS Accession No. ML13133A080), the Nuclear Regulatory Commission (NRC) issued a Request for Additional Inform ation (RAI). NPPD responded to the RAI by letter dated July 3, 2013 (ADAMS Accession N. ML13190A030).  
Cooper - Request for Additional Information Regarding Core Plate Hold Down Bolt Stress Analysis (ME9550)
 
: Dave, By letter dated January 16, 2012 (ADAMS Accession No. ML12031A249), the Nebraska Public Power District (NPPD or the licensee), submitted a report on the stress analysis of the Cooper Nuclear Station (CNS) core plate rim bolts. This report was submitted in accordance with License Renewal Commitment NLS2009100-1, as documented in NUREG-1944, whereby the licensee committed to perform an analysis of the CNS core plate rim bolts to demonstrate the adequacy of the bolts considering the loss of bolt pre-load experienced during the period of extended operation (PEO) and submit this analysis at least two years prior to entering the PEO. By letter dated May 24, 2013 (ADAMS Accession No. ML13133A080), the Nuclear Regulatory Commission (NRC) issued a Request for Additional Information (RAI). NPPD responded to the RAI by letter dated July 3, 2013 (ADAMS Accession N. ML13190A030).
By letter dated July 3, 2013, NPPD stated in response to Question P-3:  
By letter dated July 3, 2013, NPPD stated in response to Question P-3:
 
Until such time as new guidance is provided, NPPD will be performing VT- 3 inspections on 25% of core plate bolts on the top side on a periodic basis consistent with the interim guidance (i.e., 25% each 10 year interval after 2015 or until such time the BWRVIP provides alternative guidance as approved by the NRC).
Until such time as new guidance is provided, NPPD will be performing VT- 3 inspections on 25% of core plate bolts on the top side on a periodic basis consistent with the interim guidance (i.e., 25% each 10 year interval after 2015 or until such time the BWRVIP provides alternative guidance as approved by the NRC).
The NRC staff has determined that additional information is required in order to complete its review. On September 19, 2013, the NRC staff discussed this response wi th you and others of your staff. Specifically, the NRC staff has determined that VT-3 inspections from the top side of 25% of the core plate bolts every ten years provides insufficient assurance of component integrity. This staff determination is based on the limitations of VT-3 inspections, the need for assurance that a sufficient number of bolts is intact, and the statistical assurance of a 50% inspection sampling as noted in Section 3.2.2.2 of BWRVIP-25, subsection "UT."  The staff notes that the statistical argument referenced is based on UT examination which can detect partially degraded bolts, which VT-3 inspections cannot. This delta is acceptable to the staff given the applicant's analysis.  
The NRC staff has determined that additional information is required in order to complete its review. On September 19, 2013, the NRC staff discussed this response with you and others of your staff. Specifically, the NRC staff has determined that VT-3 inspections from the top side of 25% of the core plate bolts every ten years provides insufficient assurance of component integrity. This staff determination is based on the limitations of VT-3 inspections, the need for assurance that a sufficient number of bolts is intact, and the statistical assurance of a 50% inspection sampling as noted in Section 3.2.2.2 of BWRVIP-25, subsection UT. The staff notes that the statistical argument referenced is based on UT examination which can detect partially degraded bolts, which VT-3 inspections cannot. This delta is acceptable to the staff given the applicants analysis.
 
To assist in discussions, the staff referenced the safety evaluation provided for Vermont Yankee Nuclear Power Station Core Plate Hold Down Bolt Inspection Plan and Analysis dated March 15, 2012 (ADAMS Accession No. ML13127A369).
To assist in discussions, the staff referenced the safety evaluation provided for Vermont Yankee Nuclear Power Station Core Plate Hold Down Bolt Inspection Plan and Analysis dated March 15, 2012 (ADAMS Accession No. ML13127A369).  
During the teleconference, you stated that a response would be provided within 30 days of this email. Please contact me if circumstances result in the need to revise the requested response date.
 
Thanks Lynnea Lynnea Wilkins, Project Manager Fort Calhoun Station, Unit 1 Cooper Nuclear Station Plant Licensing Branch IV 1
During the teleconference, you stated that a response would be provided within 30 days of this email. Please contact me if circumstances result in the need to revise the requested response date.  


Thanks Lynnea Lynnea Wilkins, Project Manager Fort Calhoun Station, Unit 1 Cooper Nuclear Station Plant Licensing Branch IV 2Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission Phone: 301-415-1377}}
Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission Phone: 301-415-1377 2}}

Latest revision as of 14:19, 4 November 2019

Email, Request for Additional Information, Round 3, Review of License Renewal Commitment NLS2009100-1 - Core Rim Plate Bolts
ML13263A130
Person / Time
Site: Cooper Entergy icon.png
Issue date: 09/20/2013
From: Lynnea Wilkins
Plant Licensing Branch IV
To: Vanderkamp D
Nebraska Public Power District (NPPD)
Wilkins L
References
TAC ME9550
Download: ML13263A130 (2)
v • d • e


Text

Burkhardt, Janet From: Wilkins, Lynnea Sent: Friday, September 20, 2013 10:08 AM To: Van Der Kamp, David (dwvande@nppd.com)

Cc: Burkhardt, Janet

Subject:

Cooper - Request for Additional Information Regarding Core Plate Hold Down Bolt Stress Analysis (ME9550)

Dave, By letter dated January 16, 2012 (ADAMS Accession No. ML12031A249), the Nebraska Public Power District (NPPD or the licensee), submitted a report on the stress analysis of the Cooper Nuclear Station (CNS) core plate rim bolts. This report was submitted in accordance with License Renewal Commitment NLS2009100-1, as documented in NUREG-1944, whereby the licensee committed to perform an analysis of the CNS core plate rim bolts to demonstrate the adequacy of the bolts considering the loss of bolt pre-load experienced during the period of extended operation (PEO) and submit this analysis at least two years prior to entering the PEO. By letter dated May 24, 2013 (ADAMS Accession No. ML13133A080), the Nuclear Regulatory Commission (NRC) issued a Request for Additional Information (RAI). NPPD responded to the RAI by letter dated July 3, 2013 (ADAMS Accession N. ML13190A030).

By letter dated July 3, 2013, NPPD stated in response to Question P-3:

Until such time as new guidance is provided, NPPD will be performing VT- 3 inspections on 25% of core plate bolts on the top side on a periodic basis consistent with the interim guidance (i.e., 25% each 10 year interval after 2015 or until such time the BWRVIP provides alternative guidance as approved by the NRC).

The NRC staff has determined that additional information is required in order to complete its review. On September 19, 2013, the NRC staff discussed this response with you and others of your staff. Specifically, the NRC staff has determined that VT-3 inspections from the top side of 25% of the core plate bolts every ten years provides insufficient assurance of component integrity. This staff determination is based on the limitations of VT-3 inspections, the need for assurance that a sufficient number of bolts is intact, and the statistical assurance of a 50% inspection sampling as noted in Section 3.2.2.2 of BWRVIP-25, subsection UT. The staff notes that the statistical argument referenced is based on UT examination which can detect partially degraded bolts, which VT-3 inspections cannot. This delta is acceptable to the staff given the applicants analysis.

To assist in discussions, the staff referenced the safety evaluation provided for Vermont Yankee Nuclear Power Station Core Plate Hold Down Bolt Inspection Plan and Analysis dated March 15, 2012 (ADAMS Accession No. ML13127A369).

During the teleconference, you stated that a response would be provided within 30 days of this email. Please contact me if circumstances result in the need to revise the requested response date.

Thanks Lynnea Lynnea Wilkins, Project Manager Fort Calhoun Station, Unit 1 Cooper Nuclear Station Plant Licensing Branch IV 1

Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation US Nuclear Regulatory Commission Phone: 301-415-1377 2

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