Under the scope of the TMI Action Plan Item II.K.3 in NUREG-0660,[1] the NRC Bulletin and Orders Task Force conducted generic reviews of the loss-of-feedwater and small-break loss-of-coolant events on all operating reactors. These reviews consisted of an evaluation of systems reliability analyses, guidelines for emergency procedures, and operator training related to these events.
As a result of these reviews, a number of recommendations for improvements were made and documented in NUREG-0611,[2] NUREG-0626,[3] NUREG-0635,[4] NUREG-0565,[5] and NUREG-0623.[6] Included among these recommendations was the reevaluation of reactor coolant pump trip criteria.
The issue of reevaluation of reactor coolant pump trip criteria involves the potential improvement that might be achieved by establishing better criteria on when to allow the operation of reactor coolant pumps and when to trip them. It was believed that better criteria might allow the use of reactor coolant pumps to aid in recovery from certain transients while still ensuring that these pumps could be tripped during a small-break LOCA. This issue
was given consideration as a candidate USI in NUREG-0705[7] but was not recommended for designation as a USI because the safety evaluations of transients used for licensing acceptability do not assume the availability of the reactor coolant pumps.
The resolution of this issue was published in SECY-82-475.[8] This issue is also covered under TMI Action Plan Item II.K.3(5), implementation of which was mandated by NUREG-0737.[9]
[1] NUREG-0660, "NRC Action Plan Developed as a Result of the TMI-2 Accident," U.S. Nuclear Regulatory Commission, May 1980, (Rev. 1) August 1980.
[2] NUREG-0611, "Generic Evaluation of Feedwater Transients and Small-Break Loss-of-Coolant Accidents in Westinghouse Designed Operating Plants," U.S. Nuclear Regulatory Commission, January 1980.
[3] NUREG-0626, "Generic Evaluation of Feedwater Transients and Small Break Loss-of-Coolant Accidents in GE-Designed Operating Plants and Near-Term Operating License Applications," U.S. Nuclear Regulatory Commission, January 1980.
[4] NUREG-0635, "Generic Evaluation of Feedwater Transients and Small Break Loss-of-Coolant Accidents in Combustion Engineering-Designed Operating Plants," U.S. Nuclear Regulatory Commission, February 1980.
[5] NUREG-0565, "Generic Evaluation of Small Break Loss-of-Coolant Accident Behavior in Babcock & Wilcox Designed 177-FA Operating Plant," U.S. Nuclear Regulatory Commission, January 1980.
[6] NUREG-0623, "Generic Assessment of Delayed Reactor Coolant Pump Trip during Small Break Loss- of-Coolant Accidents in Pressurized Water Reactors," U.S. Nuclear Regulatory Commission, November 1979.
[7] NUREG-0705, "Identification of New Unresolved Safety Issues Relating to Nuclear Power Plant Stations," U.S. Nuclear Regulatory Commission, March 1981.
[8] SECY-82-475, "Staff Resolution of the Reactor Coolant Pump Trip Issue," U.S. Nuclear Regulatory Commission, November 30, 1982. [8306030370]
[9] NUREG-0737, "Clarification of TMI Action Plan Requirements," U.S. Nuclear Regulatory Commission, November 1980, (Supplement 1) January 1983.
Page Last Reviewed/Updated 06/24/2025