A method for the identification of a set of critical safety functions for a uranium hexafluoride conversion plant

•The purpose is to define a critical safety function set for a conversion plant.•Hazard identification techniques have been considered in the analysis.•The method has been applied to a UF6 conversion plant in the design phase.•A set of 9 critical safety functions has been proposed for the conversion plant.

The concept of critical safety functions was developed in order to improve risk management and optimize operational awareness in nuclear reactors after the accident at Three Mile Island. Currently, it is one of the requirements for licensing reactors around the world. However, this concept has not been applied to other units of the nuclear fuel cycle. With the increasing number of nuclear facilities, research on best practices already implemented and proven is necessary. This paper presents a method for identifying critical safety functions to a unit of the nuclear fuel cycle. The method was applied to the design of the conversion unit of uranium hexafluoride of Brazilian Nuclear Industries, identifying a set of nine critical safety functions that will serve as a basis for future implementation of a monitoring system based on critical safety functions.