ML20235H928
| ML20235H928 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 07/07/1987 |
| From: | Zimmerman S CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NLS-87-140, NUDOCS 8707150320 | |
| Download: ML20235H928 (2) | |
Text
7 C9&L Carolina Power & Light Company SERIAL: NLS-87-140 10CFR50.90 JUL 0 71987 87TSB01 United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555
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L BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS.1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 l
ROSEMOUNT ANALOG TRIP SYSTEM TECHNICAL SPECIFICATION SIGNIFICANT HAZARDS ANALYSIS l
Gentlemen:
l On May 1,1987, Carolina Power & Light Company (CP&L) submitted a request for a revision to the Technical Specifications (TS) for the Brunswick Steam Electric Plant (BSEP), Units 1 and 2 concerning test frequency changes for the Rosemount Analog Trip Unit Systems. Based on discussions with the NRC Project Manager for BSEP, the Company is revising the significant hazards analysis associated with this TS change as l
follows:
1.
The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated. The proposed surveillance frequency change will not decrease the Rosemount Analog Trip Unit System availability below the.999 specified in the GE Topical Report NEDO-21617-A. The study of the drif t and failure rates of the Rosemount Analog Trip Unit System in use at BSEP indicates that the trip points are highly repeatable and it has a much lower actual failure rate than assumed in NEDO-21617-A, which provided the basis for monthly surveillance.
The study shows that a test interval of six months could be used while maintaining an exceptional availability of 0.9999. Increasing the surveillance interval would reduce the number of half scrams and half group isolations required for testing, reduce out-of-service time for safety systems, decrease potential drywell leakage and potential valve failures by stroking valves inside the drywell less of ten, and reduce the potential for personnel error. A net reduction in risk (gain in safety) would be realized with the increased -
interval. In addition, the consequences of an accident will remain unchanged since no equipment or function of any piece of equipment will be changed.
2.
The proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated. No equipment or function of any piece of equipment will be changed; therefore, no possibility of a new or dif ferent kind of accident is created.
3.
The proposed amendment does not involve a significant reduction in the margin of safety. In fact, it involves a net increase in the margin of safety by providing a reduction in half scrams, half group isolations, out-of-service time for safety systems, drywell leakage and potential valve failures, and personnel error. Moreover, availability is improved, thus the margin of safety is improved.
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NLS-87-140 / Page 2 Based on the above reasoning, CP&L has determined that'the' proposed changes involve
- no significant hazards consideration.
Please refer any questions regarding this submittal to Mr. Stephen D. Floyd at.
(919) 836-6901.
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Yours very truly, i
'i JM n S R. Zim erman ager
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Nuclear Licensing Section
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BAT /pp (5231 BAT)
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cc:
Mr. Dayne H. Brown Dr. 3. Nelson Grace (NRC-Ri!)
Mr. W. H. Ruland (NRC-BNP)
Mr. E. Sylvester (NRC) 1 i
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