United States Nuclear Regulatory Commission - Protecting People and the Environment

Safety Evaluation of "Abnormal Transient Operating Guidelines" (Generic Letter 83-31)


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

                             September 19, 1983

TO ALL OPERATING REACTOR LICENSEES, APPLICANTS FOR AN OPERATING LICENSE AND 
HOLDERS OF CONSTRUCTION PERMITS FOR BABCOCK & WILCOX PRESSURIZED WATER 
REACTORS 

Gentlemen: 

SUBJECT:  SAFETY EVALUATION OF "ABNORMAL TRANSIENT OPERATING GUIDELINES" 
          (GENERIC LETTER 83-31) 

The NRC staff has reviewed the proposed Oconee Nuclear Station, Unite 3 
Abnormal Transient Operating Guidelines (ATOG) as described in Babcock & 
Wilcox (B&W) Owners Group letters dated March 31, 1982 and June 15, 1982, 
and D. Napiors letter from B&W to the Owners Group dated March 14, 1983.  As
discussed in the enclosed letter to the B&W Owners Group we have concluded 
that ATOG is acceptable as a basis for implementation of improved plant 
specific procedures and will provide improved guidance for operator 
emergency procedures over that which currently exists.  Since there is no 
generic version of ATOG for B&W plants, the utilities who are participating 
in the Owners Group program are to provide sufficient documentation in the 
form of plant-specific ATOGs and Transient Information Documents (TIDs) so 
that the NRC can perform comparisons with the ATOG version evaluated in the 
enclosed Safety Evaluation Report (SER).  We suggest that implementation of 
the guidelines proceed in 4 steps: 

(1)  Interim extension of ATOG to better cover ATWS and certain aspects 
     of natural circulation; 

(2)  Preparation of plant specific procedures which, in general, conform to   
     the ATOG referenced above and implementation of these procedures as     
     required  by Generic Letter 82-33, dated December 17, 1982; 

(3)  Preparation of supplements to the guidelines which cover changes, new    
     equipment, or new knowledge and incorporation of these supplements into  
     the procedures; and 

(4)  Completion and improvement of the guidelines to meet our long term       
     requirements, followed by incorporation of improvements into plant       
     specific procedures. 

Step 1 is to be completed before ATOG is used in the implementation of 
procedures process.  The prompt implementation of Step 2 will allow the 
benefits of the significant improvements you have achieved to be realized 
soon.  We note however, that the guidelines are written for the procedure 
writers, not control room operators, and therefore, preparation and 



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implementation of procedures will require additional Human Factors input. 
Step 3 refers to a program for guideline or procedure updates which will be 
generated as a matter of routine after the implementation.  This essentially
is a maintenance function.  Step 4 refers to a program for addressing those 
aspects of the guidelines and procedures where additional long term work may
be needed in your emergency procedure program. 

We have identified in the Safety Evaluation Report (SER) a number of items 
associated with the guidelines which need further work by the B&W Owners.  
We require that these items be addressed by either incorporating them into a
future guideline revision or otherwise justifying the disposition of the 
item. The Owners Group letter of May 4, 1983 provided a satisfactory outline 
of a plan to change the existing ATOG to a more generic document.  We share 
the Owners Group judgement that a B&W generic technical guideline will 
provide an effective mechanism for future guideline updates, changes and 
enhancements. Additionally, because the Abnormal Transient Operating 
Guidelines must be dynamic in that changes must be made to reflect change in 
equipment or new knowledge, we expect the B&W Owners' Group or a similar 
coalition of utilities and vendors to accept responsibility for continued 
maintenance of the guidelines.  Therefore, we have requested in the enclosed 
letter that the B&W Owners' Group provide a plan for addressing the SER 
items and a description of the program for steps 3 and 4 above. 

As discussed in the enclosed SER, the staff finds that ATOG represents a 
significant improvement over the guidance provided in current emergency 
operating procedures.  ATOG is symptom oriented, considers multiple 
failures, is tolerant of operator error, addresses plant cooldown following 
an emergency, and addresses inadequate core cooling.  We find the approach 
used in ATOG to be responsive to the staff's criteria.  Further, ATOG 
contains a significant quantity of valuable information for the guidance of 
operators under emergency conditions.  The guidelines provide sufficient 
guidance such that they can be translated into acceptable emergency 
operating procedures using the process identified in NUREG-0899, "Guidelines 
for the Preparation of Emergency Operating Procedures."  The staff therefore 
concludes that although efforts to improve the guidelines should continue, 
ATOG will provide a greater assurance of operational safety and are 
acceptable for implementation. 

                               Sincerely, 


                               Darrell G. Eisenhut, Director 
                               Division of Licensing 
Enclosures: 
1.  Letter to Mr. Whitney, dated September 19, 1983
2.  SER on Guidelines
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