Today, the global thermal power industry has already begun the transition to ultra-supercritical steam parameters, which makes it possible to increase the efficiency and reduce fuel consumption, and, accordingly, the discharge of harmful substances into the environment. NPPs need to increase their efficiency to maintain competitiveness in the electricity producer market. The following tasks are considered: increasing the installed capacity of operating power units by upgrading equipment, increasing the efficiency of NPPs by improving cycle arrangements and thermodynamic cycles, increasing the nuclear fuel burnup, increasing the installed capacity utilization factors (ICUF). The most common type of reactor in the nuclear power industry is the pressurized water reactor (VVER or PWR). A significant disadvantage of such reactors is the low value of the initial steam parameters (temperature and pressure). This is due to the temperature limitation equal to 350 °C for the cladding of fuel elements made of zirconium alloys. For this reason, the steam temperature in the second loop cannot exceed 315 °C. Thus, with an increase in the unit power of the units, the thermodynamic parameters of NPPs with reactors with pressurized water remain at the same level: the pressure of the primary circuit is ≈16 MPa, the temperature of the coolant at the outlet from the reactor is 320-330 °C; pressure and temperature of steam in the second loop, respectively, 6.3-7.2 MPa and 279-285 °C. The efficiency of modern NPPs with pressurized water reactors is at the level of 35%, which is lower than the efficiency of modern TPPs (45%), and significantly lower than the efficiency of steam-gas power plants (60%). One of the ways to increase the energy efficiency of NPPs with both light water and with a heavy water reactor is the improvement of the thermodynamic cycle. The paper presents the results of computer simulation of options for cycle arrangements of NPPs with a VVER-1200 reactor at reduced initial parameters using fossil-fired steam superheating, as well as steam compression to obtain ultra-supercritical steam parameters, and an assessment of the efficiency of using these cycle arrangements.