ML17317B387
| ML17317B387 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/20/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17317B386 | List: |
| References | |
| NUDOCS 7908010603 | |
| Download: ML17317B387 (2) | |
Text
SAFETY EYALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS.
AND TO FACILITY OPERATING LICENSE NOS.
NDMCH N
R PN INDIANA AND MICHIGAN PONER COMPANY DON LD C.
C OK N CL R
N DOCKET NOS. 50-315 AND 50-316 INTRODUCTION The licensee, Indiana and Michigan Power Company, in its submittal of June 6, 1979, proposed certain modifications to the safety injection actuation system logics for Donald C.
Cook Nuclear Plant, Units 1
and 2 in response to Item 3 of IE Bulletin 79-06A dated April 14, 1979.
The applicant also proposed a change to the P-11 permissive setpoint for Unit 2.
DISCUSSION Since the date of licensing until the issuance of IE Bulletin 79-06A safety injection was initiated, in addition to other parameters, based on
'oincident trip of one-of-three matched pai rs of low pressurizer level and low pressurizer pressure trips.
Item 3 of IE Bulletin 79-06A directed all facilities using pressurizer water level coincident with pressurizer pressure for automatic initiating of safety injection to trip the low pressurizer le'vel setpoint bistables so that, when pressurizer pressure reaches the low setpoint, safety injection would be initiated regardless of the pressurizer level.
Because of the concern that this action has resulted in placing D.
C.
Cook Nuclear Plant Units l,and 2 in a condition (one-out-of-three trip) which is more susceptible to spurious actuation of the safety injection sytem, the licensee has proposed the following modifications and Technical Speci-fication changes to alleviate this situation.
The Unit 2 Technical Specification for the P-ll setpoint is being changed to correct an ommission which has existed since the plant was initially licensed.
EVALUATION The proposed modification to the safety injection actuation system consists of removing the pressurizer level signal from each of the pressurizer level/
pressure channel trips and converting the system,to a two-out-of-three logic based on the pressurizer low pressure trips.
The instrumentation logic receives pressurizer pressure signals from three pressure transmitters and initiates a safety injection actuation when two of the three signals reach the low pressure setpoint of 1900 psig.
This modification does not involve a change in the setpoint.
These modifications will satisfy the requirements of IEEE 279-197 1, and other applicable standards.
The modifications will be implemented during the current outage, which will continue 'hrough at least June 15, 1979.
The other change to the Unit 2 Technical Specification increases the P-ll setpoint by 95 psi (4.92K) to 2010 psig.
The reason for this change is that the present setpoint (1915 psig) provides only a 15 psig margin between the bypass permissive and the scram point.
(In Unit 1, an 85 psi margin 4Z!
nba vs osoxag~g
is provided).
The difference in margin resulted from using the same P-11 setpoint in both units inspite of the fact that different scram points are used.
The licensee has stated that the differences in setpoint result from the assumed differences in transmitter accuracy.
h ENVIRONMENTAL CONSIDERATION We have determined that the amendments do not authorize and change go effluent types or total amounts hor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendments involve an action which is insignificant from the ktandpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact state-ment or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of these amendments.
CONCLUSION Based on.our review of the licensee's submittal, we conclude that the modifications to the safety injection actuation system logic satisfy the requirements of IEEE 279-1971 and that the changes in Technical Specifica-tions are correct; and therefore, are acceptable.
We have concluded, based on the considerations discussed above, that: (1) because the amendments do not involve an increase in the pr'obability or'onsequences of accidents previously considered and do not involve a decrease in a safety margin, the amendments do 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) su'ch activities will be conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
421 ogg