ML092870693
| ML092870693 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 10/29/2009 |
| From: | Tam Tran License Renewal Projects Branch 1 |
| To: | Nebraska Public Power District (NPPD) |
| Tran T, NRR/DLR, 415-3617 | |
| References | |
| Download: ML092870693 (9) | |
Text
October 29, 2009 LICENSEE: Nebraska Public Power District FACILITY: Cooper Nuclear Station Power Plant
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCE CALL HELD ON OCTOBER 5, 2009, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION STAFF AND NEBRASKA PUBLIC POWER DISTRICT, RELATED TO A CLARIFICATION FOR CERTAIN RESPONSES TO REQUESTS FOR ADDITIONAL INFORMATION FOR COOPER NUCLEAR STATION LICENSE RENEWAL The U.S. Nuclear Regulatory Commission staff and representatives of Nebraska Public Power District held a telephone conference call on October 5, 2009, to discuss clarifications for certain responses to requests for additional information for the Cooper Nuclear Station license renewal. provides a listing of the participants, and Enclosure 2 contains a brief description of the conference call.
The applicant had an opportunity to comment on this summary.
/RA/
Tam Tran, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-298
Enclosures:
As stated cc w/encls: See next page
ML092870693 OFFICE PM:RPB1:DLR LA:DLR PM:RPB1:DLR BC:RPB1:DLR PM:RPB1:DLR NAME T. Tran S. Figueroa B. Brady B. Pham T. Tran (Signature)
DATE 10/19/09 10/27/09 10/19/09 10/29/09 10/29/09 Memorandum to Nebraska Public Power District from Tam Tran dated October 29, 2009
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCE CALL HELD ON OCTOBER 5, 2009, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION STAFF AND NEBRASKA PUBLIC POWER DISTRICT, RELATED TO A CLARIFICATION FOR CERTAIN RESPONSES TO REQUESTS FOR ADDITIONAL INFORMATION FOR COOPER NUCLEAR STATION LICENSE RENEWAL DISTRIBUTION:
HARD COPY:
DLR RF E-MAIL:
PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRpb2 Resource RidsNrrDlrRer1 Resource RidsNrrDlrRer2 Resource RidsNrrDlrRerb Resource RidsNrrDlrRpob Resource RidsNrrDciCvib Resource RidsNrrDciCpnb Resource RidsNrrDciCsgb Resource RidsNrrDraAfpb Resource RidsNrrDraApla Resource RidsNrrDeEmcb Resource RidsNrrDeEeeb Resource RidsNrrDssSrxb Resource RidsNrrDssSbpb Resource RidsNrrDssScvb Resource RidsOgcMailCenter Resource T. Tran G. Miller (RIV)
B. Brady G. Pick (RIV)
F. Lyon I. Couret D. Roth (OGC)
A. Jones (OGC)
N. Taylor (RIV)
E. Collins (RIV)
C. Casto (RIV)
B. Maier (RIV)
V. Dricks (RIV)
D. Chamberlain (RIV)
A. Vegel (RIV)
W. Walker (RIV)
LIST OF PARTICIPANTS TELEPHONE CONFERENCE CALL COOPER NUCLEAR STATION LICENSE RENEWAL APPLICATION October 5, 2009 PARTICIPANTS AFFILIATIONS T. Tran U.S. Nuclear Regulatory Commission (NRC)
B. Brady NRC D. Nguyen NRC C. Doutt NRC R. Mathew NRC D. Bremer Nebraska Public Power District (NPPD)
W. Victor NPPD D. Lach Entergy Nuclear Operations, Inc. (Entergy)
A. Cox Entergy R. Rucker Entergy ENCLOSURE 1
COOPER NUCLEAR STATION LICENSE RENEWAL APPLICATION (Brief description of the conference call)
The U.S. Nuclear Regulatory Commission (the staff) and representatives of Nebraska Public Power District (the applicant), held a telephone conference call on October 5, 2009, to discuss clarifications for certain responses to requests for additional information (RAI) listed below.
RAI 3.6-1 In response to the staff RAI 3.6-1, the applicant stated that the 2003 event was due to the fact that the pole structure was not properly grounded, thus allowing stray voltages to build up on the high voltage insulator cold end resulting in enough heat to ignite the wooden pole cross arm. By properly grounding the cold end, the voltage potential that could be caused by corona from a similar event would be harmlessly drained to ground. The incident was event driven as a design deficiency, not an aging issue. The applicant concluded that the surface contamination of farm dust on high-voltage insulators is not an aging effect requiring management for the period of extended operation.
The staff has reviewed the applicants response and has questions about the applicants conclusion that the incident was event driven as a design deficiency not an aging issue.
Surface contamination buildup on the 345 kV high-voltage insulators caused by high humidity coupled with airborne corn/soybean particle during harvest, allowed a charge to build up on the cold end of the high-voltage insulator string due to corona. The combination of these conditions was contributed to the fire events. High humidity coupled with airborne corn/soybean particle during harvest could enable the conductor voltage to track along insulator surface more easily and can lead to insulator flashover. The buildup of surface contamination is gradual and in most areas such contamination is washed away by rain. However, a large buildup of contamination could enable the conductor voltage to track along the surface more easily. Surface contamination can be a problem in areas where there is greater concentration of airborne particles such as near the corn/soybean fields. Dust collection on high-voltage insulators and cross arms in the presence of light rain or moisture can form a film on the insulators and create a conductive path allowing electricity to flow. A small amount of electricity can leak through this path and reach the wooden cross-arm causing it to burn. Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants Section 3.6.3.2.2 recommends a plant-specific aging management program (AMP) for managing degradation of insulator quality due to presence of any surface contamination for plants located such that the potential exist for surface contaminations. The staff finds that degradation of insulator quality due to the presence of dust buildup near the corn/soybean farms is an applicable aging effect requiring management.
The staff requests the applicant to provide an applicable AMP as appropriate, or justify why surface contamination to high-voltage insulator is not an applicable aging effect requiring an aging management program at Cooper Nuclear Station (CNS).
ENCLOSURE 2
The applicant provided the following clarifications:
The staff stated: High humidity coupled with airborne corn/soybean particle during harvest could enable the conductor voltage to track along insulator surface more easily and can lead to insulator flashover. The event at CNS was not a flashover event. The airborne contaminants did not create a flashover event, but did contribute combustible material. Due to inadequate grounding of the insulator, the normal leakage current from the corona created a hotspot at the cold end of the insulator. The corn/soybean dust particles contributed to combustion near the hotspot. The design corrected the inadequate grounding, so the normal leakage current from the corona will no longer create a hotspot at the cold end of the insulator. Without a heat source, the dust from harvesting will not combust.
This is different from high-voltage insulator flashover at coastal plants associated with salt spray. The salt spray forms a film on the insulators and creates a conductive path allowing electricity to flow from the conductor over the surface of the insulator. This current is distinct from the normal leakage current from the corona. The salt spray contamination event causes flashover, not just heating at the cold end of the insulator. The dust event at CNS did not create a flashover or arcing event because a conductive path allowing electricity to flow was not created. Therefore, there is no aging effect requiring management.
In addition, this event on the 345 kV towers, which are not in scope of license renewal, is not applicable to the 161kV and 69kV towers and high voltage insulators that are in the scope of license renewal for CNS.
Followup:
The staff requested that the applicant docket a revision/supplement to the RAI response that captures the above information as well as discussion of the corona effect, normal inspection or maintenance conducted on the 161kV towers, and the frequency of farming activities that create the harvesting dust. The applicant agreed to provide a supplement to the response to RAI 3.6-1.
RAI B.1.13-1 In the basis document for AMP B.1.13, the result does not appear to clearly state that the B.1.13 AMP would be consistent with Generic Aging Lessons Learned Report recommendation with regard to the Acceptance Criteria element for this AMP.
The applicant agreed and a license renewal application (LRA) revision/amendment will be submitted.
RAI B.1.22-3 The staff requested clarification of why the test and inspection frequencies stated in NUREG-1801,Section XI.E4 were not included in the LRA Appendix A (Updated Safety Analysis Report [USAR] Supplement).
Based on the discussion of the clarification, the applicant agreed to submit an LRA revision that specifies the test and inspection frequencies stated in NUREG-1801,Section XI.E4 in USAR Supplement Section A.1.1.22.
Cooper Nuclear Station cc:
Mr. Ronald D. Asche Deputy Director for Policy President and Chief Executive Officer Missouri Department of Natural Resources Nebraska Public Power District P.O. Box 176 1414 15th Street Jefferson City, MO 65102-0176 Columbus, NE 68601 Senior Resident Inspector Mr. Gene Mace U.S. Nuclear Regulatory Commission Nuclear Asset Manager P.O. Box 218 Nebraska Public Power District Brownville, NE 68321 P.O. Box 98 Brownville, NE 68321 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Mr. John C. McClure 612 E. Lamar Blvd., Suite 400 Vice President and General Counsel Arlington, TX 76011-4125 Nebraska Public Power District P.O. Box 499 Director, Missouri State Emergency Columbus, NE 68602-0499 Management Agency P.O. Box 116 Mr. David Van Der Kamp Jefferson City, MO 65102-0116 Licensing Manager Nebraska Public Power District Chief, Radiation and Asbestos P.O. Box 98 Control Section Brownville, NE 68321 Kansas Department of Health and Environment Mr. Michael J. Linder, Director Bureau of Air and Radiation Nebraska Department of Environmental 1000 SW Jackson, Suite 310 Quality Topeka, KS 66612-1366 P.O. Box 98922 Lincoln, NE 68509-8922 Ms. Melanie Rasmussen Radiation Control Program Director Chairman Bureau of Radiological Health Nemaha County Board of Commissioners Iowa Department of Public Health Nemaha County Courthouse Lucas State Office Building, 5th Floor 1824 N Street 321 East 12th Street Auburn, NE 68305 Des Moines, IA 50319 Ms. Julia Schmitt, Manager Mr. Keith G. Henke, Planner Radiation Control Program Division of Community and Public Health Nebraska Health & Human Services R&L Office of Emergency Coordination Public Health Assurance 930 Wildwood Drive 301 Centennial Mall, South P.O. Box 570 P.O. Box 95007 Jefferson City, MO 65102 Lincoln, NE 68509-5007
Cooper Nuclear Station cc:
Mr. Art Zaremba, Director of Nuclear Mr. Dave Lach Safety Assurance LRP Entergy Project Manager Nebraska Public Power District Entergy Nuclear P.O. Box 98 1448 S.R. 333, N-GSB-45 Brownville, NE 68321 Russellville, AR 72802 Mr. John F. McCann, Director Mr. Stewart B. Minahan Licensing, Entergy Nuclear Northeast Vice President Entergy Nuclear Operations, Inc. Nuclear and Chief Nuclear Officer 440 Hamilton Avenue Cooper Nuclear Station White Plains, NY 10601-1813 72676 - 648A Avenue Brownville, NE 68321 Mr. Mike Boyce Cooper Strategic Initiatives Manager Cooper Nuclear Station 72676 - 648A Avenue Brownville, NE 68321 Mr. Dave Bremer License Renewal Project Manager Cooper Nuclear Station 72676 - 648A Avenue Brownville, NE 68321 Mr. Bill Victor License Renewal Project Licensing Lead Cooper Nuclear Station 72676 - 648A Avenue Brownville, NE 68321 Mr. Garry Young License Renewal Manager Entergy Nuclear 1448 S.R. 333, N-GSB-45 Russellville, AR 72802 Mr. Alan Cox License Renewal Technical Manager Entergy Nuclear 1448 S.R. 333, N-GSB-45 Russellville, AR 72802