3 March 2022

Physicists in Dubna and Obninsk intend to join their efforts to unravel the mysteries of Universe origin, to simulate astrophysical phenomena, and to find new types of radioactive decay. Rosatom’s Institute of Physics and Power Engineering (IPPE) and the Joint Institute for Nuclear Research (JINR) are developing a cooperation program for fundamental research with MBIR and Neptun reactors.

The multipurpose fast research reactor is now under construction in Dimitrovgrad; Neptun is a pulsed fast reactor which is planned for construction in Dubna to replace the existing IBR‑2. Pre-project work is underway to refine the engineering and economic parameters. Valery Shvetsov, Director of the JINR Neutron Physics Laboratory, explained: “Neptun is a cyclic reactor, while MBIR is a stationary reactor. In the studies conducted with extracted neutron beams, the sources of these types complement each other.”

Dmitry Klinov, IPPE Deputy Scientific Director for Prospective Topics: “MBIR is a continuous reactor that provides huge fluxes of fast neutrons in experiment cavities — the irradiation cells or the loop channels. Very significant fluxes are also generated in horizontal experimental channels where we can actually conduct research in nuclear physics, observe rare and super-rare nuclear processes induced by fast continuous spectrum neutrons. Neptun in Dubna will operate in pulse mode, allowing us to observe the same processes as in MBIR but in the region of resolved resonances characterized by certain quantum numbers. It should be noted that each of these two reactors will have the most intense neutron sources in the world. Each in its class, of course.”

“We will need many neutrons!”

Researchers from IPPE and JINR held two meetings. They have already outlined the main areas of their work with MBIR and Neptun. One of them is nuclear astrophysics. “Meteorites, comets, cosmic radiations sometimes conceal such secrets that can be revealed through neutron experiments in terrestrial conditions,” said Dmitry Klinov. Another interesting project is studying the composition of Przybylski’s star in the Centaurus constellation. Scientists predict that it consists of super-heavy elements that can exist on Earth for only a fraction of a second.

Another field is the search for new types of radioactive decay. In their experiments with neutrons with the MBIR – Neptun tandem, researchers expect to record the predicted but not yet proven phenomenon of pion decay of heavy nuclei. Dmitry Klinov: “Observing a new natural phenomenon is important in itself, but pion decay can pave the path to discovering and understanding an even deeper phenomenon: the existence of super-dense nuclear matter in terrestrial conditions. According to the idea suggested by Arkady Migdal, a theoretical physicist, super-density is associated with the so-called pion condensate. We want to detect pion decay in very sophisticated correlation experiments. And we will need a great array of neutrons.”

Valery Shvetsov believes that “Great prospects will be opened up by creating a source of ultracold neutrons in one of the MBIR channels. It is this source that will allow us to set up experiments to search for neutron-antineutron oscillations and neutron electric dipole momentum, to measure the lifetime of a free neutron, etc.” Such experiments can answer many questions about the origin of the Universe.

Other scientific problems on which experiments using the pair of reactors may shed light are multifragmentation of cold nuclei, violation of conservation laws in nuclear reactions, nuclear data for solving problems of nucleosynthesis in the Universe, nucleon stability limits for nuclei, the coexistence of aggregate states of nuclear matter, and neutron clusters. “I am sure that the program will be expanded, especially as it occurs that everyone who is not indifferent to the beauty and magic of the world of nuclei and particles joins us. Our immediate plans include establishing an international expert board on nuclear and neutron physics as part of the MBIR – Neptun collaboration. Joint scientific groups will be open to everyone, including foreign researchers,” says Dmitry Klinov.

Money and Plans

MBIR is built primarily for application purposes: it will be used to explore new materials and types of fuel, to study the emergency operation modes of various types of reactors. It is needed for the production of isotopes and for other practical tasks. Scientists hope that there will be resources for exploratory research. Dmitry Klinov: “Our country has several foundations and development institutions; organizations have their own funds. We have the Ministry of Science and Higher Education of the Russian Federation. We will knock on all doors. We have agreed with our colleagues from Dubna to prepare several projects for developing and testing the instrument facilities, conducting preliminary pilot experiments for the program of work on the MBIR – Neptun system under a single industry thematic plan for R&D.”

“As for JINR, fundamental research is exactly what we do at the expense of the Institute’s budget in line with our Charter,” added Valery Shvetsov.

In any case, it is certain for the partners that a joint R&D plan should be prepared just now. “Unique irradiation capabilities require unique techniques. Moreover, we should train the youth. After all, they will have to implement and discover tomorrow everything that we are discussing today — and to move on, for sure,” emphasized Dmitry Klinov.

Valery Shvetsov: “We must prepare the R&D program for Neptun right now since fundamental research is at the very core of why we need this reactor. It is this ambitious program that shall prove to the scientific community and funding institutions the feasibility of building the new reactor. An international group has been working actively on Neptun for more than two years now. And I am sure that a similar group will be created for joint research with IPPE at MBIR.”

Strana Rosatom

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