ATWS - Enclosing Letter To GE, With NUREG-0460, Vol. 3 (Generic Letter 79-12)

GL79012 

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

                              MARCH 12 1979 

ALL POWER REACTOR LICENSEES 

Gentlemen: 

The NRC staff finds it necessary to request additional information regarding
the capability of your  NSSS(s) to respond to postulated ATWS transients. We
have chosen, for reasons of resource conservation  and efficiency, to send 
our request for this information directly to the NSSS vendors and to 
initiate discussions regarding the nature, extent and schedule of the 
responses directly with your vendor(s). 

Enclosed for your information is a copy of a letter which was sent to 
General Electric Company,  Westinghouse Electric Corporation, Combustion 
Engineering, Inc., and Babcock and Wilcox Company,  transmitting a request 
for information needed to perform generic analyses related to ATWS. 

The analyses requested are to confirm that the proposed modifications for 
various classes of Light Water  Reactor (LWR) designs accomplish the degree 
of ATWS prevention and mitigation described by the staff in Volume 3 of 
NUREG-0460  (enclosed). 

We expect that the vendors will find it necessary to obtain some of this 
information from you. We are  asking that you provide this information in 
order to base ATWS rulemaking on generic confirmation, and  thereby avoid 
costly and unnecessary repetitive analysis. Although you will not receive 
this letter  prior to the March 1, 1979 meeting referred to, we understand 
that you were contacted by the AIF or the  respective vendor concerning the 
meeting. Should you desire an additional meeting on the generic analyses 
requested or have additional questions, please contact Mr. Ashok Thadani, 
(301) 492-7341. 

                                   Sincerely, 


                                   Richard H. Vollmer, Assistant Director  
                                        for Systems and Projects  
                                   Division of Operating Reactors 

Enclosures: 
1. Letter to General Electric Company dtd. 2/15/79 
2. NUREG-0460, Volume 3

cc w/enclosure 1: Service List