ML050820559
| ML050820559 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 04/04/2005 |
| From: | Reyes L NRC/EDO |
| To: | Wallis G Advisory Committee on Reactor Safeguards |
| Kalyanam N,NRR/DLPM,415-1480 | |
| Shared Package | |
| ML050830504 | List: |
| References | |
| G20050151, LTR-05-0106, TAC MC6305 | |
| Download: ML050820559 (6) | |
Text
April 4, 2005 Dr. Graham B. Wallis, Chairman Advisory Committee on Reactor Safeguards U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
WATERFORD STEAM ELECTRIC STATION, UNIT 3, EXTENDED POWER UPRATE
Dear Dr. Wallis:
On January 26, 2005, the staff presented its review of the Waterford Steam Electric Station, Unit 3 (Waterford 3), extended power uprate (EPU) application to the Advisory Committee on Reactor Safeguards (ACRS) Subcommittee on Thermal-Hydraulic Phenomena. During the 519th meeting of the ACRS, on February 10, 2005, the staff discussed the EPU with the ACRS Full Committee. By letter dated February 24, 2005, the ACRS forwarded its conclusions and recommendations on the staffs review of the Waterford 3 EPU application to Chairman Diaz.
In that letter, the ACRS provided the following conclusions and recommendations:
- 1. The application by Entergy for an 8 percent EPU at Waterford 3 should be approved, subject to (1) the staffs approval of the alternate source term (AST) application and (2) documentation of the resolution of the boron precipitation issue during long-term cooling for Waterford 3 by the submittal of the analysis details and their acceptance in the staffs safety evaluation (SE).
- 2. We agree with the staff that the requirement for large-transient testing should be waived for this application.
- 3. The staff should review the generic potential for boron concentration and precipitation to interfere with core cooling following a loss-of-coolant accident (LOCA).
Subsequent to the ACRS Full Committee meeting, the licensee identified the need for a revision to its EPU submittal. On March 17, 2005, the licensee provided a revised analysis for peak cladding temperature (PCT) following a large-break LOCA. Specifically, the new analysis uses a lower input value for the peak linear heat generation rate which slightly lowered the calculated PCT and maximum cladding oxidation, while increasing maximum core-wide oxidation. The
G. Wallis supplement showed that coolable geometry is maintained. The staff is currently reviewing the revised analysis to ensure conformance to the emergency core cooling criteria and will reflect review of the supplement in the SE of the Waterford 3 EPU application.
The staffs responses to the ACRS conclusions, recommendations, and comments are enclosed.
Sincerely,
/RA/
Luis A. Reyes Executive Director for Operations
Enclosure:
Staff Response to ACRS Comments cc w/enclosure: Chairman Diaz Commissioner McGaffigan Commissioner Merrifield Commissioner Jaczko Commissioner Lyons SECY
G. Wallis supplement showed that coolable geometry is maintained. The staff is currently reviewing the revised analysis to ensure conformance to the emergency core cooling criteria and will reflect review of the supplement in the SE of the Waterford 3 EPU application.
The staffs responses to the ACRS conclusions, recommendations, and comments are enclosed.
Sincerely,
/RA/
Luis A. Reyes Executive Director for Operations
Enclosure:
Staff Response to ACRS Comments cc w/enclosure: Chairman Diaz Commissioner McGaffigan Commissioner Merrifield Commissioner Jaczko Commissioner Lyons SECY DISTRIBUTION: G20050151/LTR-05-0106 See next page Accession No.: ML050820559 Package: ML050830504 Incoming: ML050660265 OFFICE PDIV-1/PM PDIV-1/LA Tech Editor PDIV-1/SC PDIV/D NAME NKalyanam DBaxley PKleene AHowe HBerkow DATE 3/23/05 3/16/05 3/21/05 3/23/05 3/23/05 OFFICE SRXB/BC SPLB/BC IPSB/BC DLPM/D NAME JWermiel JHannon (w/comment) TQuay TMarsh DATE 3/18/05 3/21/05 3/18/05 3/28/05 OFFICE NRR/D EDO NAME JDyer (BSheron for) LReyes DATE 3/30/05 4/4/05 OFFICIAL RECORD COPY
THE STAFFS RESPONSE TO ADVISORY COMMITTEE ON REACTOR SAFEGUARDS LETTER DATED FEBRUARY 14, 2005 RELATED TO THE EXTENDED POWER UPRATE FOR WATERFORD STEAM ELECTRIC STATION, UNIT 3 (WATERFORD 3)
ACRS Conclusions and Recommendations
- 1. The application by Entergy for an 8 percent extended power uprate (EPU) at Waterford 3 should be approved, subject to (1) the staffs approval of the alternate source term (AST) application and (2) documentation of the resolution of the boron precipitation issue during long-term cooling for Waterford 3 by the submittal of the analysis details and their acceptance in the staffs safety evaluation (SE).
NRC Staff Response (i) The staff review and action on Entergys AST application is scheduled to be complete in April 2005.
(ii) The licensee documented the resolution of the boron precipitation issue during long-term cooling for Waterford 3 by submitting the analysis described in its supplemental letter dated February 16, 2005 (ML050490396). The staff reviewed the licensees submittal and will document the results of its review in the EPU SE.
- 2. We agree with the staff that the requirement for large-transient testing should be waived for this application.
NRC Staff Response The staff notes the committees agreement that the large-transient testing for Waterford 3 EPU application has been waived, based on the licensees justification and the staffs agreement with that justification.
The staff believes that in case of Waterford 3, the licensee has demonstrated that the post-EPU plant performance will be adequately established by post-modification and startup testing. The licensee performed safety analyses, using NRC staff-approved methods and computer models that were applicable at power levels that envelop EPU conditions at Waterford 3. Therefore, significant insights into the capability of the facility to safely respond to upset conditions would not be expected from a large-transient test such as a turbine trip transient. The staff reviewed the licensee's arguments for waiving the large-transient testing and accepted the rationale based on consideration of the criterion in Section 14.2.1. of the Standard Review Plan.
The staff will, however, continue to evaluate the need for large-transient tests for EPUs on a case-by-case basis, based on plant-specific evaluations.
Enclosure
- 3. The staff should review the generic potential for boron concentration and precipitation to interfere with core cooling following a loss-of-coolant accident (LOCA).
NRC Staff Response Prior to the ACRS review of the Waterford power uprate, the staff identified additional generic considerations for the potential for boron precipitation to interfere with core cooling following a LOCA. The staff will communicate its concerns about the current boron concentration modeling approach to the pressurized water reactor (PWR) vendors and will work with them to modify the boron precipitation methodologies as appropriate to resolve the boron precipitation issues. The concerns the staff will pursue include the issues identified in the ACRS letter of February 24, 2005. The staff will continue to review the issue of post-LOCA boron precipitation as part of each PWR power uprate licensing action.
The staff has considered the need to enter the issue of post-LOCA boron precipitation into the agency generic issues program. However, based on its understanding of the safety significance of the issue and past consideration of the boron precipitation issue by the Office of Nuclear Regulatory Research, the staff continues to believe that the issue does not meet the threshold for evaluation as a generic safety issue. The industry should address the issue as part of the long-term cooling requirements of 10 CFR 50.46.
G20050151/LTR-05-0106 - Waterford Steam Electric Station, Unit 3, Extended Power Uprate Date: 4/4/05 DISTRIBUTION:
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