ML18022A733
| ML18022A733 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 12/06/1989 |
| From: | Becker R Office of Nuclear Reactor Regulation |
| To: | Eury L CAROLINA POWER & LIGHT CO. |
| Shared Package | |
| ML18022A734 | List: |
| References | |
| TAC-72810, NUDOCS 8912140133 | |
| Download: ML18022A733 (5) | |
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Docket No. 50-400 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 December 6,
1989 Hr. Lynn W. Eury Executive Vice President Power Supply Carolina Power 8 Light Company Post Office Box 1551
- Raleigh, North Carolina 27602
Dear t<r. Eury:
SUBJECT:
LEAD SUBMITTAL AND APPROVAL FOR REFERENCING OF WCAP-11525 BY flEtlBERS OF THE WESTINGHOUSE OWNERS GROUP (TURBINE VALVE TEST FREQUENCY EVALUATION SUBGROUP)
Enclosed is a copy of the letter issued to Northern States Power Company approving WCAP-11525 for referencing by members of the Westinghouse Owners Group (Turbine Valve Test Frequency Evaluation Subgroup) for your use.
The Prairie Island Nuclear Generating Plant, Unit Nos.
1 and 2, license amendment request is the lead submittal for the Subgroup.
I am transmitting the enclosed letter to you, as a member of the Subgroup, to facilitate your amendment request submittal.
Sincere ly,
Enclosure:
As stated cc w/encl:
See next page Richard A. Becker, Project Manager Project Directorate II-1 Division of Reactor Projects -I/II Office of Nuclear Reactor Regulation foal"toI+3--
h1r. L. W. Eury Carolina Power
& Light Company Shearon Harris CC:
Mr. R.
E. Jones, General Counsel Carolina Power
& Light Company P. 0.
Box 1551 Raleigh, North Carolina 27602 Resident Inspector/Harris NPS c/o U. S. Nuclear Regulatory Commission Route I, Box 3158 New Hill, North Carolina 27562 Mr. R.
B. Richey, Manager Harris Nuclear Project Harris Nuclear P lant P. 0.
Box 165 New Hill, North Carolina 27562 Mr. H. A. Cole Special Deputy Attorney Genera1 State of North Carolina P. 0.
Box 629
- Ra1eigh, North Carolina 27602 Regional Admin>str ator, Region II U.S. Nuclear Regulatory Commission i01 Marietta Street Suite 2900 Atlanta, Georgia 30323 Mr. C.
S. Hinnant Plant General Manager Har ris Nuclear Plant P. 0.
Box 165 New Hill, North Carolina 27562 Mr. Dayne H. Brown, Chief Radiation Protection Section Division of Facility Services N.
C. Department of Human Resources 701 Barbour Drive
- Raleigh, North Carolina 27603-2008
November 2, 1989 Enclosure Mr. D. M. Musolf, Manager Nuclear Support Services Northern States Power Company 414 Nicollet Hall Minneapolis, Minnesota 55401
Dear Hr. Muslof:
SUBJECT:
USE OF WCAP-11525 IN FUTURE LICENSE AMENDMENT REQUESTS BY WESTINGHOUSE OWNERS GROUP (TURBINE VALVE TEST FREQUENCY EVALUATION SUBGROUP MEMBERS)
By letter dated September 28,
- 1987, as supplemented by letters dated October 15,
- 1987, and June 24, 1987, Northern States Power Company (the licensee for Prairie Island Nuclear Station, Unit Nos. I and 2) requested amendments to the Technical Specificati'ons that would revise the surveillance test frequency of the turbine valves associated with turbine ovet speed protection.
Surveillance testing of these valves is necessary to assure the performance of their safety function in protecting against the consequences of a turbine missile ejection accident.
In its submittal, Northern States Power Company stated that its request was based, in part, on the report WCAP-11525, "Probabi 1istic Evaluation of Reduction in Turbine Valve Test Frequency."
It was further stated in the above-mentioned submittal that WCAP-Il525 is applicable to 17 nuclear generating units in addition to Prairie Island Unit Nos.
1 and 2.
(The report was prepared by Westinghouse.Electric Corporation for the Westinghouse Owners Group (Turbine Valve Test Frequency Evaluation Subgroup)).
The Prairie Island license amendment request was a lead submittal for the subgroup, and for.this reason, it was requested that WCAP-11525 be reviewed with the amendment request and that a separate Safety Evaluation Report be issued for WCAP-11525.
This procedure would allow for simplified review of future license amendment requests from other members of the subgroup.
C By letter dated February 7,
- 1989, license amendments to the facility operating licenses for Prairie Island Nuclear Station, Unit Nos. I and 2, were issued consisting of changes to the Technical Specifications in response to your request.
Our acceptance of the methodology described in WCAP-11525 was addressed as a supplement to the safety evaluation of the license amendment.
The purpose of this letter is to provide the staff's generic conclusions regarding license amendment requests for changes in the surveillance intervals for turbine valve tests in Technical Specifications for the remaining members of the subgroup and the applicabi lity of WCAP-11525 to support these requests.
The staff's safety evaluation for the license amendment and the supplemental safety evaluation of WCAP-11525 are provided in Enclosure l.
D. N. Huslof As referred to in the safety evaluation of the Prairie Island license amendment, the NRC staff, in a letter to Westinghouse Electric Corporation, dated February 2, 1987, proposed generic turbine failure guidelines for total turbine missile generation probabilities to be used for determining (1) frequencies of turbine disc ultrasonic inspections, and (2) maintenance and testing schedules for turbine control and overspeed protection systems.
In this letter, the NRC issued reliability criteria for maintaining the turbine in service as follows.
In general, the minimum reliability requirement for ioading the turbine and bringing the systemeon ljne is a total turbine missile generation probabi'lity of (t) )ess
[han 10 yr for a favorably oriented
- turbine, and (2) less than 10 yr for an unfavorably oriented turbine..
The safety evaluation of the Prairie Island license amendment stated that the staff requested that the licensee work with the turbine vendor to maintain a
turbine valve failure database for the purpose of tracking changes in valve failure rate; that information on the valve failure rate be included in the plant Updated Safety Analysis Report (USAR); and that the failure rate information included in the USAR be updated at least once every 3 years.
The licensee was also requested in accordance with 10 CFR 50.59 to review and reevaluate the turbine valve testing frequency probabilistic analysis (by WCAP-11525 methodology) any time that major changes in the turbine system are made or a significant upward trend in the valve failure rate is identified.
This matter was discussed with and agreed to by Nor them States Power Company.
Based on the-above, the staff has identified in Enclosure 2 the information it will need to review license amendment requests from other members of the subgroup to evaluate proposed changes in turbine valve test surveillance frequenci es.
The other licensees of the subgroup are encouraged to propose changes to Technical Specifications that are consistent with the model provided in Enclosure 3 and that are responsive to the requirements of Enclosure 2.
Proposed license amendments conforming to this guidance will be expeditiously reviewed by the NRC project manager for the facility, but those that deviate from this guidance will require a longer, more detailed review.
Licensees should contact the project manager if they have questions on this matter.
In accordance with the procedures established in NUREG-0390, "Topical Report Review Status,"
we request that the subgroup publish accepted revisions of WCAP-11525, both proprietary and non-proprietary, within 3 months of receipt of this letter.
The accepted versions should (1) incorporate this letter and its enclosures, and (2) include an "-A" (designating accepted) following the report identification number.
O. H. Huslof 3
Should our acceptance criteria or regu'Iations change so that our conclusions as to the acceptability of the report are no longer valid, the subgroup and/or the applicants referencing WCAP-11525-A will be expected to revise and resubmit their respective documentation, or to provide justification for the continued applicability of MCAP-11525-A without revision of their documentation.
S incere ly,
Enclosures:
As stated
~~~'mal~ by Ashok C. Thadani, Assistant Director for Systems Division of Engineering and Systems Technology Office of Nuclear Reactor Regulation CCNTACT: C. Nichols (301) 492-0854 0 ISTR IBUTION SPLB File JMermiel JKudrick RArchi tze 1 EButcher RDiggs (TAC 72810)
CCheng JNorberg AThadani LShao CNichols