ML20214W233
| ML20214W233 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 12/04/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20214W215 | List: |
| References | |
| NUDOCS 8612100136 | |
| Download: ML20214W233 (2) | |
Text
h UNITED STATE 3 8
i NUCLEAR REGULATORY COMMISSION h
WASHINGTON, D. C. 20555
\\...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
101 TO FACILITY OPERATING LICENSE NO. DPR-71 AND AMENDMENT N0. 130 TO FACILITY OPERATING LICENSE N0. DPR-62 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 DOCKETS NOS. 50-324 AND 50-325
1.0 INTRODUCTION
The licensee, Carolina Power & Light Company, in its submittal dated September 12, 1986, proposed to amend Appendix A, Technical Specification to Facility Operating Licenses DPR-71 and DPR-62. The proposed revision to Table 3.6.3-1 of Section 3/4.6.3 changes the allowable isolation time for the RCIC steam line isolation valves from 20 seconds to 30 seconds.
Amendment No. 126 for Brunswick-2, issued on June 10, 1986, granted a similar change on a temporary basis.
2.0 EVALUATION The licensee's submittal dated September 12, 1986, states that the limiting pipe break for equipment qualification purposes is a break in the 10 inch High Pressure Coolant Injection (HPCI) steam line. The maximum acceptable valve closure time, as specified in the plant technical specifications, is 50 seconds. The Reactor Core Isolation Cooling (RCIC) system steam line passes through the same areas as the HPCI steam line.
The RCIC steam line is a three inch line and has a maximum acceptable valve closure time, as specified in the plant Technical Specifications of 20 seconds.
The RCIC steam line isolation valves historically have closed between 18 and 20 seconds at Brunswick Units 1 and 2.
In order to provide some margin between the historical operating experience and the Technical Specification limit so as to reduce unnecessary maintenance, the licensee has proposed changing the maximum acceptable valve closure time for the RCIC steam line isolation valves. The change is from 20 seconds to 30 seconds in the Technical Specifications for Units 1 and 2.
The amount of steam lost through a three inch line in 30 seconds is significantly less than through a 10 inch HPCI line in 50 seconds, and the HPCI steamline break is the limiting line break for sub-compartment environmental conditions. The staff evaluated the radiological consequences of changing the RCIC isolation time. The design basis accident dose estimates at the site boundary are based on a 24-inch main steam line break for 10.5 seconds isolation time. The coolant loss in this accident is significantly larger than a ruptured 10-inch HPCI line for 50 seconds or a ruptured three inch RCIC line for 30 seconds.
8612100136 861204 PDR ADOCK 05000324 P
.- The dose estimates for the main steam line break accident are within the 10 CFR part 100 guideline values. Therefore, from the radiological point of view, changing the of RCIC isolation time from 20 seconds to 30 seconds is acceptable.
Consideration also has been given to the effects this. change would have on the consequences of a break on the water side of the RCIC system. The licensee has determined that the proposed change has no effect on this event because the RCIC containment isolation valves are not designed to isolate on a water line break.
There is no concern with regard to increased piping forces resulting from changing the maximum allowable RCIC isolation time from 20 to 30 seconds because maximum flow through the line is reached within seconds of a steam line rupture.
In addition, these valves close slowly, gradually throttling back the steam flow. Therefore, forces analogous to those associated with a water hammer event cannot occur.
On the basis of the above evaluation regarding changing the maximum allowable RCIC isolation time from 20 to 30 seconds, the staff concludes that the proposed Technical Specification revision is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
S The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite; and that there should be no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously published a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, the l-amendments meet the eligibility criteria for categorical exclusion set forthin10CFR951.22(c)(9). Pursuant to 10 CFR 951.22(b), no environmental impact statement or environmental assessment need be i
prepared in connection with the issuance of the amendments.
4.0 CONCLUSION
We have has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Comission's regulations and the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
A. Chu J. Ridgely Dated: December 4, 1986