Evaluation of Semi-Scale Small Break Experiment (Generic Letter 79-28)

GL79028 

                              July 10, 1979  


Mr. David Holt
B&W Owner's Group
Systems Engineer - Licensing  
Steam Production Department   
Duke Power Company 
Charlotte, North Carolina  28242

Dear Mr. Holt: 

SUBJECT: EVALUATION Of SEMISCALE SMALL BREAK EXPERIMENT 

As part of the current effort to develop improved guidelines for handling 
potential small break loss-of-coolant accidents, you are performing computer 
calculations to assess the course of such events. The computer programs used
in these analyses have been compared to only a limited amount of 
experimental data. The results of the evaluations were not conclusive and 
further verification with experimental data is required. Accordingly, it is 
requested that you perform an evaluation of the recent Semiscale small break 
experiment (5-07-10B) with your small break computer program. To be useful 
in this current effort it is essential that the work be completed by 
approximately September 1, 1979. 

The test details necessary to perform these calculations have already been 
forwarded to the reactor vendors. The analysis of the Semiscale test relates
to our previous requests regarding small breaks. If further information 
regarding the experiment is need, please contact L. E. Phillips (301) 492-
7588. 

                                        Sincerely, 


                                        Derwood F. Ross, Jr., Director 
                                        Bulletins & Orders Task Force 
                                        Office of Nuclear Reactor Regulation

cc: B&W Owner's Group Licensees