[en] Results of calculations of energy releases and temperature fields in the ultracold neutron source under design at the WWR-M reactor are presented. It is shown that, with the reactor power of 18 MW, the power of energy release in the 40-L volume of the source with superfluid helium will amount to 28.5 W, while 356 W will be released in a liquid-deuterium premoderator. The lead shield between the reactor core and the source reduces the radiative heat release by an order of magnitude. A thermal power of 22 kW is released in it, which is removed by passage of water. The distribution of temperatures in all components of the vacuum structure is presented, and the temperature does not exceed 100°C at full reactor power. The calculations performed make it possible to go to design of the source.

[en] The WWR-M reactor at NRC «Kurchatov Institute» - PNPI is going to be equipped with high-density ultracold neutron source. Method of UCN production is based on their accumulation in the superfluid helium at 1.2 K temperature. Thus, the source will provide the UCN density at EDM spectrometer equals to ρ = 1.3⋅10⁴ cm⁻³ which is 2 order magnitude greater than the output density of existing UCN source in the world. An extensive program of fundamental researches such as measuring of neutron lifetime and searching of neutron-antineutron oscillation is planned. In addition, CN and VCN beams are going to be equipped with condensed matter physics experimental setups. The design of the UCN source has been completed, complex tests at full-scale model showed that is possible to maintain superfluid helium under reactor heat load; calculations of an UCN source passive shielding, which ensures source safe operation, is completed. At the moment the process of UCN source manufacturing is taking place. (paper)