United States Nuclear Regulatory Commission - Protecting People and the Environment

Engineering Evaluation of the H. B. Robinson Reactor Coolant System Leak on January 29, 1981 (Generic Letter No. 81-22)



                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                           WASHINGTON, D.C. 20555

                                 MAY 5, 1981

TO ALL LICENSEES OF OPERATING PLANTS AND HOLDERS OF CONSTRUCTION PERMITS 

Gentlemen: 

SUBJECT:  ENGINEERING EVALUATION OF THE H. B. ROBINSON REACTOR COOLANT 
          SYSTEM LEAK ON JANUARY 29, 1981 (GENERIC LETTER NO. 81-22) 

Enclosed is our Engineering Evaluation Report for the Robinson Event. The 
primary reason for our evaluation was the loss of approximately 6,000 
gallons of reactor coolant water from two separate leaks in the letdown 
train of the Chemical and Volume Control Letdown System (CVCS). 

The evaluation is being forwarded for your information and training 
purposes. The evaluation of the event did not identify any safety concerns 
or any required immediate actions. There are four areas, however, which are 
under consideration for further action: 

1.   Whether a requirement should be placed upon operating plants to 
     establish a procedure for identification and recovery from a spurious 
     safety injection actuation (if such a procedure is not already taken 
     place). 

2.   Whether criteria for terminating SI should include provisions for 
     isolating charging since charging flow could be considered high 
     pressure safety injection for very small breaks. 

3.   Whether there is a need for a direct reactor trip on a safety injection
     actuation at other Westinghouse plants which do not have a direct trip.

4.   Whether operation of the isolation valves in the CVCS at Robinson is 
     causing the system to be operated in a manner which is contrary to its 
     design bases. 

If you have any questions regarding this evaluation, please contact your 
Project Manager. 

                              Sincerely, 


                              Darrell G. Eisenhut, Director 
                              Division of Licensing 
                              Office of Nuclear Reactor Regulation 

Enclosure:  As stated 
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