ML110680670

Request for Additional Information for the Review of the Columbia Generating Station, License Renewal Application for Drywell Floor Peripheral Seal Assembly (TAC Number ME3058)

ML110680670
Person / Time
Site:	Columbia
Issue date:	03/18/2011
From:	Cunanan A License Renewal Projects Branch 1
To:	Gambhir S Energy Northwest
Cunanan, A DLR/RPB1 415-3897
References
TAC ME3058
Download: ML110680670 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 18, 2011 Mr. S.K. Gambhir, Vice President, Engineering Columbia Generating Station Energy Northwest MD PE04 P.O. Box 968 Richland, WA 99352-0968 SUB..IECT: REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE COLUMBIA GENERATING STATION, LICENSE RENEWAL APPLICATION FOR DRYWELL FLOOR PERIPHERAL SEAL ASSEMBLY (TAC NUMBER ME3058)

Dear Mr. Gambhir:

By letter dated January 19, 2010, Energy Northwest submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54 (10 CFR Part 54), to renew Operating License NPF-21 for Columbia Generating Station, for review by the U.S. Nuclear Regulatory Commission (NRC or the 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. Further requests for additional information may be issued in the future.

Items in the enclosure were discussed with Abbas Mostala 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 301-415-3897 or bye-mail at arthur.cunanan@nrc.gov.

Sincerely, Arthur D. Cunanan, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-397

Enclosure:

As stated cc w/encl: Distribution via Listserv

COLUMBIA GENERATING STATION LICENSE RENEWAL APPLICATION REQUEST FOR ADDITIONAL INFORMATION RAI 3.5.2.2.1.4-02

Background

License renewal application (LRA) Section 3.5.2.2.1.4 discusses Loss of Material due to General, Pitting, and Crevice Corrosion and states that the drywell floor peripheral seal is made of stainless steel, which is welded to the primary containment vessel and to the underside of the circular closure girder, both of which are made of carbon structural steel. It further states in LRA Table 3.5.2-1, "Aging Management Review Results - Primary Containment," that the seal has no aging effects and verification is credited by the lSI Program - IWE and the Appendix J Program.

The FSAR provides a detailed description of the seal and its function. The drywell floor seal peripheral assembly is made from a portion of an open pipe and plates capable of carrying loads. The seal contains drywell area leaks and seals the over-under portions of the primary containment vessel.

The drywell floor peripheral seal is welded to dissimilar metals (stainless to carbon steel) and can be exposed to moisture and possible loss of material. Fabrication residual stresses combined with the prevalent thermal environment, imposed loads, and possible aggressive environment may exacerbate the potential for stress corrosion cracking (SCC).

GALL Report line item II.B4-2 discusses the possible susceptibility of stainless steel components and dissimilar metal welds to SCC. The LRA does not clearly describe how the stainless steel drywell floor seal will be managed for SCC during the period of extended operation. The staff believes that because of the difficulty of inspecting the drywe" floor peripheral seal, increasing the frequency of inspections beyond the recommendations of the lSI Program - IWE and the Appendix J Program is reasonable.

Reguests

1. Describe the environment and applied loads (e.g., thermal, seismic, etc.), to which the drywell floor peripheral seal is exposed and justify the component's capacity to perform its intended function(s) for the period of extended operation.

2. Explain how the drywell floor peripheral seal wi" be managed for SCC during the period of extended operation. If a visual examination is applied, explain what method of visual examination is used and how the interior of the seal is inspected.

3. State when the drywell floor peripheral seal was last inspected and the outcome of the inspection. Provide the inspection frequency for the component and explain why the selected frequency is appropriate.

ENCLOSURE

March 18,2011 Mr. S.K. Gambhir, Vice President, Engineering Columbia Generating Station Energy Northwest MD PE04 P.O. Box 968 Richland, WA 99352-0968

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE COLUMBIA GENERATING STATION, LICENSE RENEWAL APPLICATION FOR DRYWELL FLOOR PERIPHERAL SEAL ASSEMBLY (TAC NUMBER ME3058)

Dear Mr. Gambhir:

By letter dated January 19, 2010, Energy Northwest submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54 (10 CFR Part 54), to renew Operating License NPF-21 for Columbia Generating Station, for review by the U.S. Nuclear Regulatory Commission (NRC or the 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. Further requests for additional information may be issued in the future.

Items in the enclosure were discussed with Abbas Mostala 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 301-415-3897 or bye-mail at Slrthur.cunanan@nrc.gov.

Sincerely, IRA!

Arthur D. Cunanan, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-397

Enclosure:

As stated cc w/encl: Distribution via Listserv DISTRIBUTION:

See next page ADAMS Accession Number' ML110680670 OFFICE PM:RPB1 :DLR LA:DLR BC:RPB1 :DLR PM:RPB1 :DLR NAME ACunanan YEdmonds BPham ACunanan DATE 03/17/2011 03/16/2011 03/18/2011 03/18/2011 OFFICIAL RECORD COpy

Letter to S. Gambhir from Arthur D. Cunanan dated March 18, 2011

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE COLUMBIA GENERATING STATION, LICENSE RENEWAL APPLICATION FOR DRYWELL FLOOR PERIPHERAL SEAL ASSEMBLY (TAC NUMBER ME3058)

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