The safety of smart digital devices used in nuclear power plants - some of which were not initially designed for nuclear-related purposes - was discussed last month at a meeting in Vienna organised by the International Atomic Energy Agency (IAEA). The objective of the meeting was to establish guidance on the selection and evaluation of smart devices to be used in systems important to the safety of power plants.
Smart digital devices such as smart sensor transmitters, electrical protective devices and variable speed drives, are increasingly used at many nuclear power plants. Old and obsolete equipment in power plants is more and more often replaced with smart devices, which are electronic devices generally connected to other devices or networks via different communication protocols and are able to operate to some extent interactively and autonomously. This can include devices with properties of artificial intelligence. However, the nuclear market is too small for the development of customised smart devices specifically for power plants; therefore, operators turn to devices initially developed for other market segments and certified by non-nuclear authorities. They may require extra measures to be used for nuclear power plants.
"Smart devices can be used in equipment or systems to increase nuclear power plant safety and reliability, enhance safe operation or improve various functions," said Alexander Duchac, nuclear safety officer at the IAEA. "However, if not properly selected and qualified, they may potentially introduce new hazards, vulnerabilities, and failure modes. It's a potential issue for both operating and new nuclear power reactors."
Operators have the legal obligation to follow regulators’ safety recommendations, but regulators do not normally have access to the design information of equipment to make an informed decision on the devices' safety, the IAEA noted. The equipment qualification is very often almost impossible without cooperation from the vendor, who tends to protect the intellectual property of commercial development processes. Moreover, operators often lack guidance on how to provide sufficient information to the regulator under such circumstances.
At a meeting in February, 43 smart-device designers and developers, users and regulators from 20 countries considered best practices from around the world on demonstrating that proposed devices are suitable for application in nuclear power plants.
The IAEA plans to produce its first safety report on the use of smart devices, which will be published later this year. The report intends to provide a common technical basis for all countries. It will contain a model of how to design, select and evaluate candidate smart devices for their safe use in nuclear safety systems, including instrumentation and control, electrical, mechanical and other areas.
