ML20205L088
| ML20205L088 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 04/06/1999 |
| From: | Alexion T NRC (Affiliation Not Assigned) |
| To: | Cottle W HOUSTON LIGHTING & POWER CO. |
| References | |
| TAC-MA2246, TAC-MA2247, NUDOCS 9904140134 | |
| Download: ML20205L088 (4) | |
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UNITED STATES j
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NUCLEAR REGULATORY COMMISSION j
l WASHINGTON D.C. SpeeHem
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April 6, 1999 l
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Mr.' William T. Cottle President and Chief Executive Officer l_
STP Nuclear Operating Company l
South Texas Project Electric Generating Station P. O. Box 289 l
Wadsworth,TX 77483
SUBJECT:
INCOMPLETE CONTROL ROD INSERTION EVALUATION CRITERIA AND RESOLUTION OF INCOMPLETE CONTROL ROD INSERTION, SOUTH TEXAS PROJECT, UNITS 1 AND 2 (STP) (TAC NOS. MA2246 AND MA2247)
Dear Mr. Cottle:
The Nuclear Regulatory Commission (NRC) has reviewed STP N'Jclear Operating Company's (STPNOC's) June 25,1998, Unit 1 Cycle 8 and Unit 2 Cycle 6 inomplete centrol rod insertion (IRI) evaluation criteria and has also reviewed the material that STPNOC presented in a l
January 26,1999, meeting to discuss the resolution of the IRI problem at STP. The material presented in the January 26,1999, meeting was documented by the NRC in a meeting summary dated March 9,1999. Neither the June 25,1998, letter nor the January 26,1999, presentation material requested a written response from the NRC. However, this letter is provided to document the NRC's views.
Prior to making fuel design changes, STPNOC addressed the IRI problem by !!miting burnup in rodded fuel assemblies and with an aggressive rod drop testing plan. The NRC staff reviewed 1
both the testing program and the results of each set of tests. The June 25,1998, submittal did not change any technical content from the November 19,1997, submittal, but merely updated the applicability from June 1998 to the end of cycle for Unit 1 Cycle 8 and Unit 2 Cycle 6. The staff had previously reviewed the criteria in the November 19,1997, submittal and found them
- acceptable. The continuation of the criteria as stated in the June 25,1998, letter was also found acceptable.
To adoress the IRI problem, STPNOC conducted or sponsored post-irradiation examinations, mechanical analysis of span / assembly bow, fuel analysis of the previous and improved fuel
' designs, IRI susceptibility thresholds, and an independent review of IRI analyses. STPNOC also made several fuel design changes, resulting in the Phase 2 or robust fuel design. The l
analyses and modeling presented at the January 26,1999, meeting show that the assembly average bumup threshold for no IRI is predicted to be at 57,000 MWD /MTU with the robust fuel design. In addition, for the current Unit 2 Cycle 7 (the new fuel in this core is of the robust fuel design), STPNOC is planning rod drop tests if a plant shutdown occurs and end-of-cycle rod drop tests, in addition to the beginning-of-cycle tests required by the Technical Specifications.
l End-of-cycle tests will continue for the future robust-fueled cores until STPNOC observes s
i satisfactory performance at bumups approaching the approved burnup limit.
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,e W.T Cottle Overall, STPNOC has pursued an aggressive and multi-faceted approach to resolve the IRI problem. The staff recognizes that IRI is a complex problem that depends on fuel and power history variables that were previously not recognized as important. The staff will continue to follow this issue.
Sincerely, y/k h
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Thornas W. Alexion, Project Man ger, Section 1 Project Directorate IV & Decommissioning Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499 cc: See next page s
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W. T. Cottle Overall, STPNOC has pursued an aggressive and multi-faceted approach to resolve the IRI problem. The staif recognizes that IRI is a complex problem that depends on fuel and power history variables that were previously not recognized as important. The staff will continue to follow this issue.
Sincerely, 1
ORIGINAL SIGNED BY:
Thomas W. Alexion, Project Manager, Section 1 Project Directorate IV & Decommissioning Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499 cc: See next page plSTRIBUTION:
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Mr. William T. Cottle STP Nuclear Operating Company tiouth Texas, Units 1 & 2 L
cc:
Mr. Cornelius F. O'Keefe Jack R. Newman, Esq.
. Senior Resident inspector -
U.S. Nuclear Regulatory Commission 1800 M Street, N.W.
P. O. Box 910 Wi shington, DC 20036-5869 Bay City, TX 77414 Mr. T. H. Cloninger Vice President A. Ramirez/C. M. Canady Engineering & Technical Services City of Austin STP Nuclear Operating Company Electric Utility Department P. O. Box 289 721 Barton Springs Road Wadsworth,TX 77483 Austin,TX 78704 Office of the Govemor Mr. M. T. Hardt ATTN: John Howard, Director Mr. W. C. Gunst Environmental and Natural City Public Service Board Resources Policy P. O. Box 1771 P. O. Box 12428 San Antonic,TX 78296 Austin, TX 78711
' Mr. G. E. Vaughn/C. A. Johnson
'Jon C. Wood Central Power and Light Company Matthews & Branscomb P. O. Box 289 One Alamo Center MailCode: N5012 106 S. St. Mary's Street, Suite 700 Wadsworth,TX 74483 San Antonio,TX 78205 3692 INPO:
Arthur C. Tate, Director Records Center Division of Compliance & Inspection 700 Galleria Parkway Bureau of Radiation Control Atlanta, GA 30339-3064 Texas Department of Health 1100 West 49th Street Regional Administrator, Region IV Austin,TX 78756 U.S. Nuclear Regulatory Commission
' 611 Ryan Plaza Drive, Suite 400 Jim Calloway Arlington,TX 76011 Publi1 Utility Commission of Texas Elect.ic Industry Analysis D. G. Tees /R. L. Balcom P. O. Box 13326 Houston Lighting & Power Co.
Austin, TX 78711-3326 P. O. Box 1700 Houston, TX 77251 -
Judge, Matagorda County -
Matagorda County Courthouse 1700 Seventh Street Bay City, TX 77414
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