Study on the relationship between the temperature rise limit of the heat dissipation area of NPPs and the thermal impact of marine species

Taking a typical coastal nuclear power plant as an example, eight representative important species that are sensitive to temperature rise in the local sea were selected as tested species to carry out Critical Thermal Maximum (CTM) experiments and upper incipient lethal temperature (UILT₅₀) experiments. The results of CTM experiment show that there is little difference in CTM range of the tested species in each season, and seasonal factors have little impact on CTM. The results of UILT₅₀ experiment show that UILT₅₀ range of the tested species in summer is higher than that of the other three seasons, and the difference between UILT₅₀ ranges of winter, spring and autumn is small. Taking the temperature rise value of the thermal impact experiment as the maximum thermal tolerance temperature rise value of an representative important species, the lower limit of the maximum thermal tolerance temperature rise range of the two species tested in the thermal impact experiment both occurs in summer. Among them, the lower limit of the temperature rise value for CTM experiment is 8.7°C, the lower limit of temperature rise value for UILT₅₀ experiment is 5.0°C. For conservative consideration, 5.0°C can be used as temperature rise limit on the boundary of the thermal discharge heat dissipation area in this typical nuclear power plant.