MEPhI: A method to significantly increase the safety of nuclear rectors

2022: Development of a method to significantly increase the safety of "reactors of the future"

The NRNU MEPhI announced on August 22, 2022, the development of a method for significantly increasing the safety of "reactors of the future." This will be achieved by surrounding the reactor core with a radiogenic lead reflector.

Illustration: alternathistory.com

We are talking about the so-called fast reactors with lead coolant, which belong to the fourth generation (Generation IV) of nuclear facilities. Those nuclear reactors that are being built for industrial use in 2022, experts attribute to the "three plus" generation. Compared to them, the fourth generation of nuclear rectors should be more safe and efficient, and this should be achieved not due to "smart" electronics and other settings, but due to design features and better use of physical principles.

Theoretically, the efficiency of fast neutron reactors with lead coolant can reach 50%, while most nuclear plants in industrial operation in Russia have this figure at 30%. To create a new type of reactor, it is necessary to solve many more scientific and technical problems, and among them - to exclude the possibility of a nuclear reaction getting out of control (as happened at the infamous Chernobyl nuclear power plant). This is what the development of the Institute of Nuclear Physics and Technology of the National Research Nuclear University MEPhI is devoted to.

The essence of the development lies in the manufacture of a reflector surrounding the reactor core from radiogenic lead (that is, lead with a large content of lead-208 isotope). The reflector of this material will have special properties. First of all, it will hardly release neutrons formed during the nuclear reaction outside the core, that is, almost all neutrons will be returned to the core. But, most importantly, they will not be returned immediately, but after a relatively long time (due to the large atomic weight of lead-208). Therefore, the use of a lead-208 reflector in a fast reactor will radically increase the average neutron life time (by about 3 orders of magnitude!), Which will significantly improve its nuclear safety in the event of an emergency introduction of positive order reactivity and a more effective share of delayed neutrons into it. Indeed, transients in this case are much slower and manageable. This will avoid many emergencies, explained one of the authors of the development, associate professor of the Department of Theoretical and Experimental Physics of Nuclear Reactors NRNU MEPhI, Evgeny Kulikov.

Reflectors from lead-208 in the future may become commonplace in nuclear power. In August 2022, an experimental fast neutron reactor with a lead coolant is BRYeST-OD-300 being built in the city of SeverskTomsk Region.