ML061360122
| ML061360122 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 05/23/2006 |
| From: | Fields M Plant Licensing Branch III-2 |
| To: | Terao D Plant Licensing Branch III-2 |
| Fields M , NRR/DORL,415-3062 | |
| Shared Package | |
| ML061360116 | List: |
| References | |
| Download: ML061360122 (5) | |
Text
May 23, 2006 MEMORANDUM TO: David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
Mel B. Fields, Senior Project Manager
/RA/
Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION, UNIT 1 -
SUMMARY
OF MEETING HELD ON MAY 11, 2006, HIGH-LEVEL VIBRATION ISSUE IN SHUTDOWN COOLING LINE On May 11, 2006, Arizona Public Service Company (APS), the licensee for Palo Verde Nuclear Generating Station (Palo Verde), Units 1, 2, and 3, met with the Nuclear Regulatory Commission (NRC) staff at NRC Headquarters in Rockville, Maryland. The purpose of the meeting was to discuss the vibration issue present in the Palo Verde Unit 1 shutdown cooling (SDC) lines.
The discussions included a description of the vibration history, the phenomena that the licensee believes is causing the high vibrations, and the physical modifications underway to eliminate the high-level vibration. The vibrations were detected several fuel cycles ago but did not prevent the unit from operating at normal power levels until it exited the fall 2005 refueling outage.
Since exiting this outage, the licensee has not operated the unit above approximately 32%
power due to the vibration levels in this SDC line. Unit 1 is currently shutdown and defueled to implement modifications to eliminate the high-level vibrations.
The licensee believes that the direct cause of the vibration condition is the development of pressure pulsations in the SDC line resulting from coupling between the fundamental acoustic frequency of the SDC suction line and the sheer layer instability (vortex shedding) due to reactor coolant system flow over the SDC suction nozzle.
The physical modifications underway to eliminate the high-level vibration consist of relocating the isolation valve closest to the reactor coolant system hot leg to a location closer to the hot leg. The licensee believes that this modification will increase the acoustical frequency away from shedding modes and pipe modes.
A list of attendees is provided as an enclosure to this memorandum. There were no members of the public represented at the meeting. The slides used during the meeting by APS are available in the Agencywide Documents Access and Management System under Accession Number ML061360368.
Docket No. 50-528
Enclosure:
As stated cc w/encl: See next page
May 23, 2006 MEMORANDUM TO:
David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
Mel B. Fields, Senior Project Manager
/RA/
Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION, UNIT 1 -
SUMMARY
OF MEETING HELD ON MAY 11, 2006, HIGH-LEVEL VIBRATION ISSUE IN SHUTDOWN COOLING LINE On May 11, 2006, Arizona Public Service Company (APS), the licensee for Palo Verde Nuclear Generating Station (Palo Verde), Units 1, 2, and 3, met with the Nuclear Regulatory Commission (NRC) staff at NRC Headquarters in Rockville, Maryland. The purpose of the meeting was to discuss the vibration issue present in the Palo Verde Unit 1 shutdown cooling (SDC) lines.
The discussions included a description of the vibration history, the phenomena that the licensee believes is causing the high vibrations, and the physical modifications underway to eliminate the high-level vibration. The vibrations were detected several fuel cycles ago but did not prevent the unit from operating at normal power levels until it exited the fall 2005 refueling outage. Since exiting this outage, the licensee has not operated the unit above approximately 32% power due to the vibration levels in this SDC line. Unit 1 is currently shutdown and defueled to implement modifications to eliminate the high-level vibrations.
The licensee believes that the direct cause of the vibration condition is the development of pressure pulsations in the SDC line resulting from coupling between the fundamental acoustic frequency of the SDC suction line and the sheer layer instability (vortex shedding) due to reactor coolant system flow over the SDC suction nozzle.
The physical modifications underway to eliminate the high-level vibration consist of relocating the isolation valve closest to the reactor coolant system hot leg to a location closer to the hot leg. The licensee believes that this modification will increase the acoustical frequency away from shedding modes and pipe modes.
A list of attendees is provided as an enclosure to this memorandum. There were no members of the public represented at the meeting. The slides used during the meeting by APS are available in the Agencywide Documents Access and Management System under Accession Number ML061360368.
Docket No. 50-528
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION PUBLIC LPLIV r/f RidsNrrDorlLplg RidsNrrPMMFields RidsNrrLADJohnson RidsNrrDorlDpr RidsOgcRp RidsAcrsAcnwMailCenter RJasinski, NRR JWu PYChen KManoly TScarbrough MGutiersez SOConnor, EDO RIV RidsRgn4MailCenter (TPruett)
MTG. NOTICE Accession No.: ML061160141 SLIDES Accession No.: ML061360368 ADAMSPKG.: ML061360116 ADAMS Accession No.: ML061360122 NRC-001 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/LPL4/BC NAME MFields;mxr4 DJohnson DTerao DATE 5/18/06 5/22/06 5/23/06
OFFICIAL RECORD COPY
Enclosure MAY 11, 2006 ARIZONA PUBLIC SERVICE COMPANY PALO VERDE NUCLEAR GENERATING STATION, UNIT 1 HIGH-LEVEL VIBRATION ISSUE IN SHUTDOWN COOLING LINE LIST OF ATTENDEES Arizona Public Service Company Carl Churchman Mo Karbassian Craig Seaman Bob Yamrus Robert Blevins M. K. Au-Yang Frank Ferrarraccio Winston Borrero Jeff Brown U. S. Nuclear Regulatory Commission Kamal Manoly David Terao Mel Fields P. Y. Chen Tom Scarbrough Mauricio Gutiersez John Wu
March 2006 Palo Verde Generating Station, Units 1, 2 & 3 cc:
Mr. Steve Olea Arizona Corporation Commission 1200 W. Washington Street Phoenix, AZ 85007 Mr. Douglas Kent Porter Senior Counsel Southern California Edison Company Law Department, Generation Resources P.O. Box 800 Rosemead, CA 91770 Senior Resident Inspector U.S. Nuclear Regulatory Commission P. O. Box 40 Buckeye, AZ 85326 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower & Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 Chairman Maricopa County Board of Supervisors 301 W. Jefferson, 10th Floor Phoenix, AZ 85003 Mr. Aubrey V. Godwin, Director Arizona Radiation Regulatory Agency 4814 South 40 Street Phoenix, AZ 85040 Mr. Craig K. Seaman, General Manager Regulatory Affairs and Performance Improvement Palo Verde Nuclear Generating Station Mail Station 7636 P.O. Box 52034 Phoenix, AZ 85072-2034 Mr. Matthew Benac Assistant Vice President Nuclear & Generation Services El Paso Electric Company 340 East Palm Lane, Suite 310 Phoenix, AZ 85004 Mr. John Taylor Public Service Company of New Mexico 2401 Aztec NE, MS Z110 Albuquerque, NM 87107-4224 Mr. Thomas D. Champ Southern California Edison Company 5000 Pacific Coast Hwy Bldg D1B San Clemente, CA 92672 Mr. Robert Henry Salt River Project 6504 East Thomas Road Scottsdale, AZ 85251 Mr. Jeffrey T. Weikert Assistant General Counsel El Paso Electric Company Mail Location 167 123 W. Mills El Paso, TX 79901 Mr. John Schumann Los Angeles Department of Water & Power Southern California Public Power Authority P.O. Box 51111, Room 1255-C Los Angeles, CA 90051-0100 Mr. Brian Almon Public Utility Commission William B. Travis Building P. O. Box 13326 1701 North Congress Avenue Austin, TX 78701-3326
March 2006 Palo Verde Generating Station, Units 1, 2 & 3 cc:
Ms. Karen O'Regan Environmental Program Manager City of Phoenix Office of Environmental Programs 200 West Washington Street Phoenix AZ 85003 Mr. James M. Levine Executive Vice President, Generation Mail Station 7605 Arizona Public Service Company P. O. Box 52034 Phoenix, AZ 85072-2034