In 2019, Russian researchers successfully tested the RED-100 Neutrino Detector in the laboratory. The detector is designed for remote monitoring of processes in reactors of nuclear power plants. This facility has no analogues in the world capable of detecting neutrinos and cosmic rays. With the help of such a detector, it is possible to remotely monitor the state of the reactor, conduct its isotope analysis, predict emergency situations and even prevent the development of nuclear weapons.

Nuclear reactions lead to the formation of a large number of neutrinos. These structureless elementary particles have not yet been sufficiently studied. It is known that they are harmless to living organisms, easily pass through the human body and objects and are difficult to detect.

The most powerful source of neutrinos is the Sun, but the fluxes of these particles are also produced by nuclear reactors. Since neutrinos cannot be stopped by any shielding, they pass freely through the concrete and lead protection of the NPP. By analyzing the neutrino radiation, one can understand what is happening in the reactor core, and even identify the isotopic composition of the nuclear reaction.

RED-100 was designed at the National Research Nuclear University MEPhI for the detection of neutrinos and the subsequent creation of portable devices based on this detector. The National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) is the major University of the nuclear industry of the Russian Federation. One of the main tasks of the University is to train physicists, engineers, programmers, computer security specialists in accordance with the requests of industry companies (the Ministry of Defense and Rosatom Corporation). It is among the top 100 world Universities in physical sciences and the first in Russia among Engineering Universities.

Russian scientists from several Institutes, including the NRC “Kurchatov Institute”, MIPT, JINR and others, also took part in the creation and testing of the detector. The work of the researchers was supported by the Russian Science Foundation.

RED-100 is a new-generation ultra-sensitive detector that uses 200 kg of liquid xenon placed in a titanium cryostat as a working medium. Interaction of neutrinos with the atomic nucleus of xenon leads to the ionization of the medium and the production of several free electrons, which cause a strong glow of the gas, so it is easy to detect.

The existing neutrino detectors are gigantic in size – a whole train is needed for transportation. The compactness of RED-100 is a serious advantage of its development – devices based on it can be easily fit into a truck. This was achieved thanks to a new principle discovered by Russian scientists. The detector is based on a new physical effect discovered in 2017 – the effect of Elastic Neutrino-Nucleus Scattering. No one had ever used it for neutrino detection before.

The development has already attracted the attention of the leadership of the International Atomic Energy Agency (IAEA). Officials controlling the operation of nuclear power plants around the world became very interested in the possibility of effective remote monitoring of reactor operations.

With the help of devices based on RED-100, the IAEA staff could monitor the operations of nuclear power plants somewhere in Pakistan or in Iran, without visiting NPP. In any operating reactor, its isotopic composition changes. The detector can detect the production of, for example, plutonium-239, which is produced by reactors and can be used in nuclear weapon production.

In general, devices based on the new detector should improve the safety of NPPs, since they can be used to monitor the reactor operation standards. With the help of RED-100, it will be possible to monitor the normal course of reactor operation. Detector-based devices can be used as an additional means of monitoring the course of a nuclear reaction, which is of great importance for improving the safety of nuclear energy. There is an opportunity to prevent another Chernobyl- or Fukushima-like disaster.

The detector can be used to detect radiation from the Sun and cosmic rays, but its main task is to detect neutrinos.

Half a century ago, the leading nuclear powers developed a set of diplomatic and technological safeguards to prevent nuclear proliferation. They strictly regulate the circulation of clean and spent nuclear fuel and oblige all parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) to allow UN and IAEA inspectors to audit NPPs and other facilities.

Scientists have been trying to solve the problem of nuclear reactor safety for a long time, developing new methods for detecting traces of fissile materials and other types of inspection of nuclear facilities that could be carried out remotely without interfering with operation processes. One of the first examples of such remote systems can be the RED-100 Neutron Detector.

In 2021, the neutron detector was successfully tested at the Kalinin NPP. A full-scale inspection of the facility showed that the detector can detect traces of electron neutrinos and at the same time ignore the effects of cosmic rays on xenon and other sources of interference. The detector can monitor what is going on inside the operating nuclear reactor from outside, non-invasively. This will prevent emergencies, and thus increase the safety of nuclear power and, even more importantly, prevent the proliferation of nuclear weapons.

This “guard” resembles a barrel filled with 200 kg of liquid xenon. And although billions of neutrinos fly out of the reactor, it is a great success if one can catch at least a few dozens. The fact is that the particles do not show themselves in any way, they do not interact with anything. Therefore, scientists have to use tricks to trap this elusive particle.

What exactly does neutrino report about the situation in a nuclear reactor? How does it make out a diagnose? And most importantly, how does it catch by the hand those who are trying to extract nuclear weapons from it? The fact is that during the operation of the reactor, the composition of isotopes in it is gradually changing: some of them are growing (weapons-grade plutonium), and some are decaying. And these changes leave their mark in the neutrino flux, which the “guard” detects. One can tell by it whether everything is normal there or there is cause for alarm. And whether there is any plutonium produced by intruders for nuclear weapons.

Russia supplies nuclear power plants almost all over the world and is responsible to the International Community so that other states do not use them to cause harm to humanity. It is very difficult to control what exactly is going on at a station in another country if there is no device that can literally be placed on the street next to NPP to monitor changes in the isotopic composition of the nuclear reactor and prevent illegal removal of radioactive materials from it.