Energy for building heating purposes (space and domestic hot water) accounts for 15% of world energy consumption, with twice as high total heat needs, including heat for industrial purposes. This is provided mainly with non-renewable sources: natural gas, oil, coal, and waste. Thermal networks from nuclear energy offer a solution to reducing carbon emissions by providing space and water heating for a group or district of buildings from a large central heating source.
At all nuclear plants, the reactor core’s primary process is converting nuclear energy into heat. This potential has been conclusively demonstrated in several countries (mainly in Eastern Europe and Russia) and is still being utilized, although to a minimal extent. This creates a significant, untapped potential in Canada to harness nuclear process heat for industrial and urban thermal network applications. Most existing and prospective thermal network systems utilize hot water as the energy carrier. Typical supply temperatures in the district heating networks are 80 to 130◦C, with exact values depending on the specific system’s design and current weather conditions. Water with such temperatures can be easily generated in a steam cycle nuclear power plant, where the live steam temperature is around 280–300◦C.
The development of Small Modular Reactors (SMRs) makes combined heat and power arrangements more attractive. These designs incorporate enhanced safety features, require smaller investments, pose fewer financial risks, and may be easier to site closer to end-users. The advanced designs of SMRs being developed in Canada for domestic customers and exported to global markets include low-temperature applications that extract “waste heat” from the back end of the turbine at about 200 C. The low-temperature (>300C) application that SMR developers cite most commonly is thermal networks, which involves steam >200 C from the reactor or the waste heat from the turbine delivered to industrial and residential users.