United States Nuclear Regulatory Commission - Protecting People and the Environment

Actions Required from OL Applicants of B & W Designed NSSS Resulting from NRC B & O Task Force Review of TMI2 Accident (Generic Letter 80-33)



GL80033 

                                                                ENCLOSURE 2 

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

                              April 24, 1980 

TO ALL PENDING OPERATING LICENSE APPLICANTS OF NUCLEAR STEAM SUPPLY SYSTEMS 
     DESIGNED BY BABCOCK AND WILCOX 

SUBJECT:  ACTIONS REQUIRED FROM OPERATING LICENSE APPLICANTS OF NUCLEAR 
          STEAM SUPPLY SYSTEMS DESIGNED BY BABCOCK AND WILCOX RESULTING  
          FROM THE NRC BULLETINS AND ORDERS TASK FORCE REVIEW REGARDING THE 
          THREE MILE ISLAND UNIT 2 ACCIDENT 

In our letter of September 27, 1979, to all pending operating license 
applicants concerning followup actions resulting from our reviews regarding 
the Three MIle Island Unit 2 accident, we indicated that each applicant 
would receive additional guidance from the NRR Bulletins and Orders Task 
Force. This guidance would be related to (1) Auxiliary Feedwater (AFW) 
systems, and (2) analyses for small break loss-of-coolant accidents and 
inadequate core cooling, including guidelines for emergency operating 
procedures. 

The purpose of this letter is to advise you of the information we require 
related to Auxiliary Feedwater systems. The requirements were identified 
during the course of the NRR Bulletins and Orders Task Force review of 
pressurized water reactor nuclear steam supply systems in light of the Three
Mile Island Unit 2 accident. 

Auxiliary Feedwater (AFW) Systems  

The Three Mile Island Unit 2 accident and subsequent investigations and 
studies highlighted the importance of the AFW system in the mitigation of 
transients and accidents. Following the Three Mile Island 2 accident, 
operating plants having nuclear steam supply systems designed by Babcock and
Wilcox were shutdown. During these shutdowns short-term actions were taken 
to improve the reliability of the AFW system. As part of the long-term 
requirements of the shutdown of these plants, more systematic reliability 
analysis of the AFW system has been conducted by the licensees. The staff is
currently evaluating these analyses. Also as part of is assessment of the 
Three Mile Island Unit 2 accident and related implications for operating 
plants, the staff evaluated the reliability of AFW systems for all operating
plants having nuclear steam supply systems designed by Westinghouse and 
Combustion Engineering. 

The objectives of the staff's study, related to operation of pressurized 
water nuclear steam supply system was (a) to identify necessary chances  in 
AFW system design or related operating procedures at operating plants in 
order to assure continued safe operation of these plants, and (b) to 
identify other system characteristics in the AFW system design of these 
plants which on a long-term basis may require system modifications to 
improve reliability. 

8012010 
.

                                  - 2 -

To accommodate these objectives the staff reviewed plant-specific AFW system
designs in light of current requirements, and assessed the relative 
reliability of which was the initiating event at Three Mile ISland Unit 2, 
and other AFW system failure due to common causes, single point 
vulnerabilities and human error. 

It should be noted that, because of time personnel limitations, our 
evaluation of AFW systems was limited to operating reactors at the time 
these studies were initiated. Our review of these systems. Some of these 
changes were generic and others were plant specific. A summary of the 
techniques used in our evaluation is provided in Enclosure 1.* 

With respect to operating license applications such as yours, we will 
require the you (a) provide an evaluation which show how your AFW system 
meets each requirement in Standard Review Plan 10.4.9 and Brach Technical 
Position ASB-10-1, (b) perform a reliability evaluation similar in method to 
that described in Enclosure 1 that was performed for operating plants and 
submit it for staff review, (c) factor the recommendations of Enclosure 1 
into your plant design, and (d) respond to Enclosure 2, which requests the 
information necessary to determine the design basis for your AFW system flow 
requirements and to verify that your AFW system will meet these 
requirements. 

You are required to provide the information discussed above as an amendment 
to your application. Your schedule for submittal should take into 
consideration our requirement that both staff approval of your AFW design 
and actual accomplishment of any necessary modifications be completed prior 
to issuance of a full power license, as reflected in item II.E.1.1 of the 
TMI Action Plan (NUREG-0660). 

                                        Sincerely, 


                                        D. F. Ross, Jr., Acting Director 
                                        Division of Project Management 
                                        Office of Nuclear Reactor Regulation

Enclosures:
As stated

cc: Service Lists

*Enclosure 1 is Appendix III to the staff generic evaluation of Westinghouse
designed plants, NUREG-0611. The techniques described and recommendations 
are applicable to Combustion Engineering and Babcock and Wilcox designed 
plants. 

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