Nuclear power waste heat enhanced salinity-gradient osmotic energy conversion with warm drained seawater

The power density of salinity-gradient osmotic energy conversion (OEC) is usually low due to performance limitation of ion exchange membranes, which can be fortunately enhanced by thermal modulation. In addition, about 67 % of the fission energy produced in nuclear reactors is released as low-grade waste heat causing serious thermal pollution to environment. Therefore, we report utilization of nuclear power waste heat (NPWH) to enhance OEC. A theoretical study was firstly conducted to predict enhanced OEC performance with China Hongyanhe, Tianwan, and Daya Bay nuclear power plants (NPPs) in three seasons at various power levels. Then, relevant experimental studies demonstrate the effectiveness of NPWH enhanced OEC. The maximum improvement on osmotic power density (OPD) reaches 37.27 % compared with that without utilization of NPWH from warm drained seawater. Besides, a decrease in the NPP latitude with an increased environmental temperature strengthens NPWH enhanced OPD, and a maximum OPD of 3.871 W/m² is accomplished. Furthermore, the OPD rises with increase of NPP power. When the power level of Tianwan NPP in spring increases from 20 % to 100 % full power, its NPWH enhanced maximum OPD is consolidated by 52.42 %. This study provides a novel win-win idea to enhance salinity-gradient OEC using environmentally harmful NPWH.