ML20040E926
| ML20040E926 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 01/29/1982 |
| From: | Holahan G Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20040E925 | List: |
| References | |
| NUDOCS 8202080097 | |
| Download: ML20040E926 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF' NUCLEAR REACTOR REGULATION
~RELATED TO AMENDMENT N0. 12 TO LICENSE NPF-9' DUKE POWER COMPANY INTRODUCTION As a result of.a reactor trip and safety injection (due to frozen instrument line) on January 11, 1982, the Boron Injection Tank (BIT) discharged its concentrated; boric acid into the reactor coolant system. According to Technical Specification 3/4.5.4 the plant could not restart until the boron concentration in the BIT was returned to 20,000 PPH. To prevent a delay in restarting the riant, the licensee requested a tegorary Technical Specification change.
DISCUSSION The Boron Injection Tank provides for rapid injection of boron following a Safety Injection signal. This injection of boron helps mitigate the reactivity transient
._resulting from a steamline break -(particularly for the design-basis case, including a stuck rod). Long terra shutdown of the plant following a steamline break is assured by the injection of borated water from the Refueling Water Storage -Tank.
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The licensee's letter of. January-11,1982, indicates that the existing safety analysis of the steamline break accident is based on an assumed end-of-life :
moderator temerature coefficient of -41 PCM/ F, a shutdown margin of 1.6L and a BIT boric acid concentration of 20,000 PPM. The letter also indicates that the current plant conditions Mrresponding to the beginning of the first cycle are:
a moderator temerature coefficient of -10 PCM/ F and a shutdown margin of _3.27%.
The licensee concluded th!, a steamline break under the present conditions would be nuch less severe than the conditions analyzed in the FSAR.
EVALUATION The staff has evaluated the effect of. reducing the required boric acid concentration in the BIT from 20,000 PPM to 2,000 PPM, for a seven day period.
We agree with the.
licensee's conclusions, relative to the consequences of a steamline break, that the reduction in the Bli boric acid concentration would be more than offset by the-reduced reactivity insertion associated with the less negative troderator temperature coefficient and the increased shutdown' margin associated with the'present conditions
-and the mode of operation. The seven day limitation for the proposed Technical-Specification assures that no significant change in the moderator temperature coeffi-cient.or shutdown margin will occur.
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Based on the information provided by the licensee and our independent assessment of the acceptability of the consequences of a postulated steamline break accident, we conclude that the proposed modification to Technical Specification 3/4.5.4 will not result in an undue risk-to the health.and safety of the public. The proposed change is therefore acceptable.
ENVIRONMENTAL CONSIDERATION We have-determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will.not result in any signif-icant environaental irrpact. Having made this determination, we have further con-cluded that the anendment involves an action which is insignificant from the stand-point of environmental inpact and, pursuant to 10 CFR Section 51.5(d)(4), that an
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environmental impact statenant or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
q CONCLUSION 3
Uc have concluded, based on the consideration discussed above, that: (1) because the 4
amendaunt does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration,.
(2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be i
conducted in compliance with the Conmission's regulations and the issuance of this.
amendaent will not be inimical to the conmon defense and security or.to the health and safety of the public.
4 Date: January 29, 1982 l
Principal Contributor:
G. llolahan, ORAB t
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