Feasibility of Rankine cycle improvement for LWR power plant is studied. In LWR, the main steam is saturated steam, thus steam turbine is mostly operated in wet region. Therefore, the moisture separation plays a key role to achieve better turbine plant efficiency. Typical reheating configuration for present LWR plant is single reheating after HPT by MSR.
On the other hand, it is well known that the increasing of numbers of moisture separation or reheat improves the turbine plant efficiency. Double reheat cycle is common for fossil power plant and also has been proposed for LWR. However, double reheat cycle has not been adopted to actual nuclear power plant yet since the double reheat configuration makes heating and drain system complicated, and larger MSR shell and diameter piping are required due to the increase of steam volume flow.
In this paper, improved Rankine cycle with high pressure moisture separator (HP-MS) and improved low pressure loss MSR (LP-MSR) is studied in order to increase the plant efficiency. Using CFD analysis and scale model test, we confirmed pressure loss and moisture separation characteristic of LP-MSR. The performance of improved Rankine cycle with this new MSR was calculated and the results show that the electrical output of typical LWR Plant may increase 1% or more from single reheat cycle.