ML19260A483
| ML19260A483 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 10/30/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19260A478 | List: |
| References | |
| NUDOCS 7911210253 | |
| Download: ML19260A483 (3) | |
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UNITED STATES 8 \\,"f (j NUCLEAR REGULATORY COMMISSION E
WASHING TON, D. C. 20555 l
g v lf SAFETY EVA'.UATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 30 TO FACILITY OPERATING LICENSE NO. DPR-6 CONSUERS PONER COMPANY BIG ROCK POINT DOCKET NO. 50-155
1.0 INTRODUCTION
By letter dated September 28, 1979, Consumers Power Company (CPC)
(the licensee) requested changes to the Technical Soecifications for the Big Rock Point Plant.
The proposed changes would add restrictions to reduce the likelihood of uncovering the reactor core during certain plant conditions. The proposed changes are in response to an abnormal occurrence event report related to the Oyster Creek Nuclear Plant (Federal Register, Volume 44, No.170, August 30, 1979).
2.0 DISCUSSION AND EVALUATION On May 2,1979, a loss of feedwater event occurred at Oyster Creek Nuclear Generating Station, which resulted in a significant reduction of water inventory above the reactor core. We detemined during our review of the event at Oyster Creek that four other boiling water reactors, including Big Rock Point would be susceptible to a similar event.
Big Rock was in an " extended shutdown at the time of the Oyster Creek event and we stated in the Federal Register notice noted above, that we would impose appropriate requirements on Big Rock Point prior to its startup.
We identified two additional Technical Specification requirements appropriate for Big Rock Point. These are:
(1) a Technical Specification on the minimum number of non-isolated forced circulation loops is required, and (2) a reactor water level safety limit Technical Specification must be established.
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The event at Oyster Creek resulted in a substantial decrease in core water level because of partial isolation of all recirculation lines during the transient. The major concern which arose from this event is that the reactor core could be effectively isolated from its source of reactor coolant, the annulus region, Therefore, because of the design similarities between Oyster Creek and Big Rock Point, we have concluded that a Technical Specification on the minimum number of non-isolated recirculation loops is required to assure adequate comunication between the core and annulus regions. We have reviewed analyses of natural circulation through loops similar to those of Big Rock Point and have also evaluated the specific recirculation loop and reactor vessel internals configurations.
Based on these evaluations, we have concluded that one open loop will provide adequate comunication between core and annulus region. The requirement for the non-isolation of one recirculation loop, under all conditions where possible depletion of core inventory may occur, has been incor-porated into the Technical Specification 4.1.2(b) on the above bases.
(This specification is in effect during reactor power operations which corresponds to all conditions where reactor core outlet temperature is greater than 212*F.)
A second requirment is to establish a reactor vessel water level safety l imit.
The licensee has specified actions which are appropriate to safety limit violation in the event reactor vessel water level decreases below the safety systems set point. This specified action reauires (1) an immediate shutdown, (2) notification to the USNRC, (3) a written report and (4) an NRC authorization before startup. These requirements are specified in Section 10 of the plant Technical Specifications, Administrative Controls, Subsection 6.7, Safety Limit Violation.
Based on the,iscussion above, we conclude that the proposed changes to the Technical Specifications are appropriate requirenents and would reduce the likelihood of a significant reduction of water inventory above the reactor core. We, therefore, find the proposed changes acceptable, 3.0 ENVIR0t#iENTAL 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 significant environmental impact. Having made this detemination, we have further concluded that the amendment involves an action which is insignificagt fran the standpoint of environmental impact and pursuant to 10 CFR s51.5(d)(4) that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
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4.0 CONCLUSION
S We have concluded, based on the considerations discussed above, that:
(1) because the amendment 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 conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the pu blic, Date:
October 30, 1979 1382 203