Since its emergence, neutron nuclear physics has demonstrated its effectiveness, becoming the basis of nuclear power engineering and a tool for studying the nuclear structure and properties of fundamental interactions. The tasks that this area of research faced in the early 21st century are still of particular importance. They echo the questions that were formulated by the international scientific community when discussing the prospects for the development of nuclear physics (NuPECC, Long Range Plan 2017).
Main goals of the current stage of research are:
- Experimental and theoretical investigation of symmetry breaking effects in reactions with neutrons and fundamental properties of the neutron to test the parameters of the Standard Model and search for "new physics".
- Investigation of the properties of excited nuclei, reactions with emission of charged particles, fission physics.
- Obtaining of relevant data for astrophysics, nuclear power engineering and nuclear waste transmutation problem using neutron- and gamma-induced reactions.
- Application of neutron physics methods in other fields of science and technology.
- Development and construction of detectors of neutrons and other ionizing radiation, as well as applied methods in nuclear physics with neutrons.
- Development of the Intense REsonance Neutron Source (IREN) and the experimental base at the IREN and IBR-2 facilities.
Nuclear neutron methods (such as activation analysis) have found wide applications as a powerful analytical method in environmental, biological research and archeology. These methods are widely known to be used to study the surface of planets of the Solar System. The application of these methods in several industries holds much promise. The study of cross sections for interactions of neutrons with nuclei for the needs of nuclear power engineering is still of considerable significance.
The extensive field of research is opened with the use of UCN. Traditional attempts are related to new physics beyond the SM through measurements of neutron lifetime and electric dipole moment. However, it seems that recent observations of UCN quantum states in a gravitational field have much prospect. Indeed, it is a new research field including the investigation of dark matter and dark energy and especially precise measurements of structure and dynamics of surfaces at nanoscale.
Ultracold Neutrons (UCN) and New Physics 
UCN physics is traditional for FLNP. Note that UCN have been discovered in FLNP by F.L.Shapiro’s group in 1968. FLNP scientists are taking part almost in all leading experiments with UCN in the world and have a few new ideas to be implemented at a new more intense neutron source.
