ML091540412
| ML091540412 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 06/10/2009 |
| From: | Richard Plasse License Renewal Projects Branch 2 |
| To: | Wadley M Northern States Power Co |
| Plasse, Richard 301-415-1427 DLR/RPB2 | |
| References | |
| TAC MD8513, TAC MD8514 | |
| Download: ML091540412 (3) | |
Text
June 10, 2009 Mr. Michael D. Wadley Site Vice President Prairie Island Nuclear Generating Plant, Units 1 and 2 Northern States Power Company, Minnesota 1717 Wakonade Drive East Welch, MN 55089
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION (TAC NOS. MD8513 AND MD8514)
Dear Mr. Wadley:
By letter dated April 11, 2008, Nuclear Management Company, LLC, now known as Northern States Power Company, Minnesota, submitted an application pursuant to Title 10 of the Code of the Federal Regulations Part 54 (10 CFR Part 54), to renew the operating license for Prairie Island Nuclear Generating Plant, Units 1 and 2, 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 Mr. Gene Eckholt of your staff, 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 301-415-1427 or by e-mail at Richard.Plasse@nrc.gov.
Sincerely,
/RA/
Richard Plasse, Project Manager Projects Branch 2 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-282 and 50-306
Enclosure:
As stated cc w/encl: See next page
June 10, 2009 Mr. Michael D. Wadley Site Vice President Prairie Island Nuclear Generating Plant, Units 1 and 2 Northern States Power Company, Minnesota 1717 Wakonade Drive East Welch, MN 55089
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION (TAC NOS. MD8513 AND MD8514)
Dear Mr. Wadley:
By letter dated April 11, 2008, Nuclear Management Company, LLC, now known as Northern States Power Company, Minnesota, submitted an application pursuant to Title 10 of the Code of the Federal Regulations Part 54 (10 CFR Part 54), to renew the operating license for Prairie Island Nuclear Generating Plant, Units 1 and 2, 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 Mr. Gene Eckholt of your staff, 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 301-415-1427 or by e-mail at Richard.Plasse@nrc.gov.
Sincerely,
/RA/
Richard Plasse, Project Manager Projects Branch 2 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-282 and 50-306
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION:
See next page ADAMS Accession Number: ML091540412 OFFICE PM:RPB2:DLR LA:DLR BC:RPB2:DLR PM:RPB2:DLR NAME RPlasse IKing DWrona RPlasse DATE 06/9/09 06/9/09 06/9/09 06/10/09 OFFICIAL RECORD COPY
Letter to Michael D. Wadley from Richard A. Plasse dated June 10, 2009
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION (TAC NOS. MD8513 AND MD8514)
DISTRIBUTION:
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Prairie Island Nuclear Generating Plant, Units 1 and 2 cc:
Peter M. Glass Assistant General Counsel Xcel Energy Services, Inc.
414 Nicollet Mall (MP4)
Minneapolis, MN 55401 Manager, Regulatory Affairs Prairie Island Nuclear Generating Plant Northern States Power Minnesota 1717 Wakonade Drive East Welch, MN 55089 Manager - Environmental Protection Division Minnesota Attorney General=s Office 445 Minnesota St., Suite 900 St. Paul, MN 55101-2127 U.S. Nuclear Regulatory Commission Resident Inspector's Office 1719 Wakonade Drive East Welch, MN 55089-9642 Administrator Goodhue County Courthouse Box 408 Red Wing, MN 55066-0408 Commissioner Minnesota Department of Commerce 85 7th Place East, Suite 500 St. Paul, MN 55101-2198 Tribal Council Prairie Island Indian Community ATTN: Environmental Department 5636 Sturgeon Lake Road Welch, MN 55089 Charles R. Bomberger Vice President of Nuclear Projects 414 Nicollet Mall, (MP4)
Minneapolis, MN 55401 Dennis L. Koehl Chief Nuclear Officer Northern States Power Minnesota 414 Nicollet Mall (MP4)
Minneapolis, MN 55401 Joel P. Sorenson Director, Site Operations Prairie Island Nuclear Generating Plant Northern States Power Minnesota 1717 Wakonade Drive East Welch, MN 55089
ENCLOSURE PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION REQUEST FOR ADDITIONAL INFORMATION Follow-up RAI B2.1.38 In letter L-PI-08-098, dated December 5, 2008, Responses to NRC Requests for Additional Information Dated November 5, 2008 Regarding Application for Renewed Operating Licenses, the applicant submitted responses to the staffs RAIs. In addition, the applicant provided information during a public meeting on March 2, 2009, and a previous follow-up RAI in letter L-PI-09-047, April 6, 2009.
On May 28, 2009, the NRC staff performed an audit at the Prairie Island Nuclear Generating Station (PINGP), Units 1 and 2, related to the supporting documentation for the reactor cavity leakage. The staff reviewed the following documents:
References:
- 1. Dominion Energy Incorporated, Evaluation of Effects of Borated Water Leaks on Concrete Reinforcing Bars and Carbon Steel Plate of the Containment Vessels at Prairie Island Units 1 and 2, Report No. R-4448-00-01, Rev. 0.
- 2. Prairie Island Nuclear Generating Station, Refueling Cavity leakage, Event Date 1988-2008, Report No. RCE 01160372-01, Volumes 1 and 2.
In order to complete our review of issues related to the PINGP reactor cavity leakage discussed in the above referenced reports, the staff requests the following additional information:
a) Section 2.2 of Reference 1 recommends that a test be performed to determine if there is high assurance that the pH present in the water between the containment steel plates and concrete is more than 12.5. Please provide a schedule for performing this test.
b) Section 2.2 of Reference 1 recommends removal of concrete inside the containment at the following locations:
- i.
Sump C ii. Through the wall at elevation 695 closer to the transfer tube However, Northern States Power Company, Minnesota (NSPM) in a letter dated April 6, 2009, committed to remove concrete from Sump C only. Please clarify. In addition, please explain why removal of concrete from Sump C is not planned during the next scheduled outages at PINGP, Units 1 and 2.
c) Section 4.2 of Reference 1 has identified an upper bound loss of 0.25 inch in the 1.50 inch steel containment due to borated water corrosion over a 36 year period.
Please advise if the stresses in the steel containment remain within the American Society of Mechanical Engineers Code allowable values for this loss of 0.25 inches.
According to Section 4.1 of Reference 1, minimum thickness required for the steel containment for all loading conditions is 1.4908 inches. In addition, please clarify if NSPM has considered the potential of continued reactor cavity leakage over the life extension period of 60 years.
d) In Section 5.2.3 of Reference 1, the rate of degradation estimated for PINGP concrete is two times that used previously for Salem/Connecticut Yankee plants to account for the difference in the type of concrete aggregates at PINGP. Please advise if NSPM has performed or intends to perform any tests to confirm the use of this assumption for the degradation rate.
e) Section 5.2.6 of Reference 1 states, concrete is not relied upon for tensile strength (tensile strength provided by rebar). Please explain how formation of large thru thickness cracks will affect the transverse shear capacity of concrete slabs and walls.
Shear strength of concrete is directly related to the tensile strength.
f) Section 5.2.6 of Reference 1 states, Degradation of concrete by exposure to borated water can also occur at cracks in the concrete. This could lead to loss of strength of concrete in a narrow band through thickness of material. A crack across thickness of material may expose rebars to corrosion. Please explain how this effect is considered in determining the structural integrity of concrete walls and slabs.
g) Section 5.2.3 of Reference 1 estimated the upper bound loss of concrete depth over a 36 year period to be 0.31 inches. Please address the impact of this loss of 0.31 inch of concrete behind the stainless steel liner plate on the load carrying capacity of the stainless steel liner plate.
h) NSPM in a letter dated April 6, 2009, committed to visual inspections during the consecutive refueling outages of the areas where reactor cavity leakage has been observed following refueling cavity leak repairs in each unit. Which aging management program (AMP) will be used to address this issue?
i) Page 52 of Reference 2 identified five recommendations to address reactor cavity leakage. Please provide NSPMs action plan and schedule for completing these five recommendations.