Light-water reactors pressure-temperature operating

The supercritical water-cooled reactor is a normal light water reactor (LWR) that has increased temperature and pressure. The purpose is to place the water in the primary coolant loop into a supercritical state, which would dramatically increase operating efficiency. 

In light water reactors, the radionuclides are exclusively deposited into the surface oxide layers of the piping, components, etc., while the base materials (with the exception of the materials inside the reactor pressure vessel which are neutron-activated) are free of radioactivity. This fact is a fundamental difference from reactors that operate at higher temperatures (e. g. liquid-metal cooled reactors), where the deposited radionuclides are able to diffuse into the base material to a significant... 

The primary coolant parameters have been chosen from the well-proven range of working pressures and temperatures typical of light water reactors. Consideration has been also made of experience in the operation of nuclear propulsion power plants in the modes of natural circulation of the primary coolant. The maximum primary coolant temperature at the core outlet (data averaged over the cross-section) can be taken equal to 330°C. Considering the above mentioned decrease of temperature due to fuel bum-up, this value would amount to 320°C at the end of life prior to maintenance shutdown. Under natural circulation of the primary coolant, the temperature difference between the core outlet and inlet will be no less than 70°C. Thus, the minimum temperature of the primary coolant will be 250°C. 

A concept has been developed for a low-temperature, low-pressure, low-power-density, low-cool-ant-flow-raie light water reactor (LWR) that destroys plutonium quickly without using uranium or thorium. This concept is very safe and could be designed, constructed, and operated in a reasonable time frame. 

To take advantage of the opportunities for improving safety afforded by a reactor operating at low power density, a plutonium-burning reactor that is cooled by low-temperature, low-pressure light water flowing at low velocity is recommended. 

Y. Oka and K. Yamada, Research and Development of High Temperature Light Water Cooled Reactor Operating at Supercritical-Pressure in Japan, Proc. ICAPP 04, Pittsburgh, PA, June 13-17, 2004, Paper 4233 (2004)... 

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