Feasibility Assessment of Hydrogen Superheating of NPP Steam with Load-Following Mode

This paper is concerned with the superheating feasibility of the nuclear steam supply system (NSSS) steam using hydrogen. A comparison is made between the power plant turbine and an additional turbine considering load-following operation. It is shown the additional turbine unit enables to reduce the thermomechanical stress by 60 MPa, achieve a substantial reduction of its equivalent operating hours (EOHs) from 5,280 to 637 hours, and maintain the turbine lifetime. In fact, a temperature increase of over 100°C is not recommended due to a considerable decline in the lifetime. According to the calculation, the energy production cost throughout peak hours with the steam superheating by 25°C is lower if the main turbine operates 15 hours a day and higher in the case of five hours a day. A temperature increase of 100°C shows either no difference between the two variants or a better result for the main turbine, and this is not affected by the rate of the temperature change (TCR). It is also presented that a decrease in the operation time with the superheating and the additional turbine leads to the price increase of 0.82-0.83 rub./kWh while the main turbine use with the superheating increases the price by 0.82-1.09 rub./kWh. Additionally, the influence of the TCR on the efficiency is negligible during peak hours.