ML043100197
| ML043100197 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 11/04/2004 |
| From: | Macon W NRC/NRR/DLPM/LPD4 |
| To: | Parrish J Energy Northwest |
| Macon W, NRR/DLPM,415-3965 | |
| References | |
| IR-02-005, LER 02-001-00 | |
| Download: ML043100197 (4) | |
Text
SENSITIVE - NOT FOR PUBLIC DISCLOSURE November 4, 2004 Mr. J. V. Parrish Chief Executive Officer Energy Northwest P.O. Box 968 (Mail Drop 1023)
Richland, WA 99352-0968
SUBJECT:
COLUMBIA GENERATING STATION - FINAL ACCIDENT SEQUENCE PRECURSOR ANALYSIS OF FEBRUARY 2002 OPERATIONAL CONDITION
Dear Mr. Parrish:
Enclosed for your information is the final Accident Sequence Precursor (ASP) analysis of an adverse condition which was identified at Columbia Generating Station in February 2002. This condition involved a replacement of 16 circuit breakers equipped with a mechanism operated cell (MOC) switch that was retained when the replacement was made. However, the MOC switches were not recalibrated, resulting in intermittent failure to assure a full closure of the new circuit breakers upon demand. This condition affected the circuit breakers of four safe shutdown systems for a duration of approximately seven months.
This condition is documented in LER 397/02-001, and was determined to be of low to moderate safety significance (WHITE) in accordance with the Significance Determination Process (SDP) as documented in NRC Inspection Report 50-397/02-005 dated May 22, 2002. This is similar to the results of the final ASP analysis, with an increase in mean core damage probability (CDP) of 6.1x10-6. This condition is an accident precursor (i.e., a condition which results in a change in conditional core damage probability (CCDP) > 1x10-6).
For the February 2002 condition, the findings in the ASP analysis (change in CCDP and dominant risk contributors) are consistent with those in the SDP. Since this ASP analysis confirms the results of the final significance determination, which has been reviewed by the NRC staff and Energy Northwest, it is being issued as a final product for information only. In the past, preliminary versions of all ASP analyses were issued for internal peer review by the NRC staff and for external peer review by the licensee. Comments received from these reviews were then resolved as part of the final analysis. To increase efficiency, we are now issuing the "noncontroversial" ASP analyses as final documents.
The NRC staff is continuing to review the appropriate classification of these documents within our records management, considering changes in our practices following the events of September 11, 2001. Using our interim guidance, the enclosed analysis has been marked as "Sensitive Information" in accordance with Section 2.390 of Title 10 of the Code of Federal Regulations. Please control the document accordingly (i.e., treat the document as if you had determined that it contained trade secrets and commercial or financial information that you considered privileged or confidential). We will inform you if the classification of the document changes as a result of our ongoing assessments.
"Document transmitted herewith contains sensitive unclassified information. When separated from the enclosure, this document is decontrolled."
SENSITIVE - NOT FOR PUBLIC DISCLOSURE
J. Parrish Note that public access to ADAMS has been temporarily suspended so that security reviews of publicly available documents may be performed and potentially sensitive information removed.
Please check the NRC Web site for updates on the resumption of ADAMS access.
If you have any questions regarding the analysis, please contact me at 301-415-3965.
Sincerely,
/RA/
William A. Macon, Project Manager, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-397
Enclosure:
Accident Sequence Prescursor Analysis (Sensitive - Not for Public Disclosure) cc w/o encl: See next page
J. Parrish November 4, 2004 Note that public access to ADAMS has been temporarily suspended so that security reviews of publicly available documents may be performed and potentially sensitive information removed.
Please check the NRC Web site for updates on the resumption of ADAMS access.
If you have any questions regarding the analysis, please contact me at 301-415-3965.
Sincerely,
/RA/
William A. Macon, Project Manager, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-397
Enclosure:
Accident Sequence Prescursor Analysis (Sensitive - Not for Public Disclosure) cc w/o encl: See next page DISTRIBUTION: (w/o enclosure)
PUBLIC PDIV-2 Reading RidsNrrDlpmPdiv (HBerkow)
RidsNrrDlpmPdiv2 (RGramm)
RidsNrrPMWMacon RidsNrrLAEPeyton RidsRgnIVMailCenter (AHowell, BJones)
RidsOgcRp RidsAcrsAcnwMailCenter RidsNrrPMGDick DMarksberry, RES AGrady, RES ACCESSION NOS.:
Transmittal Letter: ML043100197
Enclosure:
ML042360175 OFFICE PDIV-2/PM PDIV-2/LA PDIV-2/SC NAME WMacon EPeyton RGramm DATE 11/4/04 11/4/04 11/4/04 OFFICIAL RECORD COPY
Columbia Generating Station cc w/o Encl:
Mr. Dale Atkinson (Mail Drop PE08)
Vice President, Technical Services Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Mr. Albert E. Mouncer (Mail Drop PE01)
Vice President, Corporate Services/
General Counsel/CFO Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Chairman Energy Facility Site Evaluation Council P.O. Box 43172 Olympia, WA 98504-3172 Mr. D. W. Coleman (Mail Drop PE20)
Manager, Performance Assessment and Regulatory Programs Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Ms. Christina Perino (Mail Drop PE20)
Manager, Licensing Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Chairman Benton County Board of Commissioners P.O. Box 190 Prosser, WA 99350-0190 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 69 Richland, WA 99352-0069 Mr. Rodney L. Webring (Mail Drop PE04)
Vice President, Nuclear Generation Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Thomas C. Poindexter, Esq.
Winston & Strawn 1400 L Street, N.W.
Washington, DC 20005-3502 Mr. Bob Nichols Executive Policy Division Office of the Governor P.O. Box 43113 Olympia, WA 98504-3113 Ms. Lynn Albin Washington State Department of Health P.O. Box 7827 Olympia, WA 98504-7827