Abstract <p>Software has been developed to simulate experiments with ultracold neutrons (UCN) at the PIK reactor (Gatchina, Russian Federation). Using this software, the neutron guide system was optimized, through which neutrons are supplied from the UCN source to the experimental installations. The calculations considered two options: with a straight neutron guide and a neutron guide with a downward bend. For a bent neutron guide, when separating membranes are placed at the bottom of the neutron guide, neutrons pass through them at increased velocity due to gravitational acceleration. Due to this, it is possible to reduce neutron losses. Monte Carlo calculations showed that in an experiment to search for the electric dipole moment of a neutron, an accuracy of 1 × 10^–27 e cm/year can be obtained, and in an experiment to measure the neutron lifetime, the statistical uncertainty can be improved to 0.1 s.</p>