Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
GL80020
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 20555
March 10, 1980
TO ALL PENDING OPERATING LICENSE APPLICANTS OF NUCLEAR STEAM SUPPLY
SYSTEMS DESIGNED BY WESTINGHOUSE AND COMBUSTION ENGINEERING
SUBJECT: ACTION REQUIRED FROM OPERATING LICENSE APPLICANTS OF NUCLEAR
STEAM SUPPLY SYSTEMS DESIGNED BY WESTINGHOUSE AND COMBUSTION
ENGINEERING 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
nuclear steam supply systems designed by Westinghouse and Combustion
Engineering 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. As part of its assessment of the Three Mile
Island Unit 2 accident and related implications for operating plants, the
staff evaluated the 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 nuclear steam
supply systems designed by Westinghouse, were (a) to identify necessary
changes 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 accommodate these objectives the staff reviewed plant-specific AFW system
designs in light of current requirements, and assessed the relative
reliability of the various AFW systems under various loss-of-feedwater
transients, one of which was the initiating event at Three Mile Island Unit
2, and other postulated potential failure conditions by determining the
potential failure conditions by determining the potential for AFW system
failure due to common causes, single point vulnerabilities and human error.
.
It should be noted that, because of time and personnel limitations, our
evaluation of AFW systems was limited to operating reactors at the time
these studies were initiated. Our review of these systems resulted in the
identification of changes required for current AFW 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 that you (a) provide an evaluation which shows how your AFW system
meets each requirement in Standard Review Plan 10.4.9 and Branch Technical
Position ASB-10-1, (b) perform a reliability evaluation similar in method to
that described in Enclosed 1 that was performed for operating plants and
submit it for staff review, 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.
We recognize that operating license applicants for certain facilities, e.d.,
Salem Unit 2, and North Anna Unit 2, may be essentially identical to plants
for which we have identified AFW system modifications. In such instances,
information already provided for the operating plants may be directly
applicable to plants under review for an operating license. It is
acceptable to the staff if you reference such information in your response.
However, you must also include a description of any differences between the
operating plant and the plant under review for an operating license and
provide justification in order for us to determine if the resolution for the
operating plant is applicable to your facility.
Provide the information discussed above as an amendment to your application.
Your schedule for submittal should take into consideration that the current
version of the Task Action Plan requires staff review and approval of this
information prior to issuance of a full power license.
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 3 to the staff generic evaluation of Westinghouse
designed plants. The techniques described and recommendations are
applicable to Combustion Engineering designed plants.
