My blogging about commercial nuclear reactors has focused on the generation of electricity from such reactors. In addition to generating electricity, the heat given off by nuclear reactors can also be used directly for industry and district heating. District heating is a system that distributes heat generated in a central location through a network of insulated pipes to residential and industrial consumers. Residences use the heat for space heating and to heat water. There are two values assigned to the output of a commercial power plant. Watts can be a measure of both electricity and heat.
Pool-type light water nuclear reactors (also called swimming pool reactors) feature a core immersed in an open pool of normal water. The water serves as a neutron moderator, coolant and radiation shield. One of the benefits of a pool reactor is that the cooling system is operating at normal air pressure and temperature. This makes the reactor much safer to work around. These reactors burn enriched uranium that is less than twenty percent U-235 which is considered highly enriched uranium. Pool reactors are not used to generated electricity but have been used as heat sources. They cannot meltdown as commercial power reactors may do. And they have very low emissions of radioactive materials which makes them desirable for use in urban areas.
China began researching the possible application of nuclear power to heating in the early 1980s. During 1983 and 1984, the Institute of Nuclear Energy and Technology (INET) at Tsinghua University used its experimental pool-type reactor to provide heating for nearby buildings. Also during that time, INET constructed two nuclear heating reactors. One of those reactors was a deep pool-type and the other one was a regular vessel-type reactor. INET built a five Megawatt experimental thermal pool-type reactor called the NHR5 between 1986 and 1989. The larger production prototype NHR200-II was constructed based on the design of the NHR5.
The China National Nuclear Corporation (CNNC) has been constructing and studying experimental pool reactors for over fifty years. The China Institute of Atomic Energy recently operated a pool-type reactor for one hundred sixty-eight hours. Following this success, the CNNC started an independent research and development program with their Yanlong pool-type reactor (also known as DHR-400) in November of 2017.
CNNC said, “The Yanlong reactor is an effective way to improve China's energy resource structure by utilizing nuclear energy for district heating, and to ease the increasing pressures on energy supplies. Nuclear energy heating could also reduce emissions, especially as a key technological measure to combat haze during winter in northern China. Thus, it can benefit the environment and people's health in the long run."
The Yanlong reactor “can be constructed either inner land or on the coast, making it an especially good fit for northern inland areas, and it has an expected lifespan of around 60 years. In terms of costs, the thermal price is far superior to gas, and is comparably economical with coal and combined heat and power.”
China General Nuclear and Tsinghua University are working on a feasibility study for the first commercial nuclear plant dedicated to district heating. The plant would use the technology developed for the NHR200-II. The president of Shanghai Nuclear Engineering Research & Design Institute and senior vice president of State Nuclear Power Technology Company said that using fossil fuels for heating is creating terrible pollution in China during winter months. He also said, "To prevent air pollution and to enhance human life, we think that nuclear power, especially the use of nuclear energy to supply district heating, is very important."