Researchers at the Czech Technical University in Prague and the University of West Bohemia in Pilsen have devised an innovative solution that uses the radioactive decay heat produced by used fuel rods to heat water. The team, led by professor Radek Skoda, has already patented this technology, named the Teplator. Skoda told Germany’s Deutsche Welle on 7 April that the Teplator’s dimensions are similar to those of research reactors already operating in Europe. However, it is simpler in terms of technology and design and “only” generates heat and not power.

"It would be possible to heat all big Czech cities just from the reserves of used fuel already available today in the Czech Republic," said Skoda. "The type of used fuel that the Teplator was designed for is not only used in Czech nuclear power plants but also, for example, in the Greifswald nuclear plant in eastern Germany that is now shut. The used fuel could be used in our Teplator to heat Leipzig or Halle." He said that this could be done at about half the cost of a gas-powered plant.

The simplest version of the Teplator has been designed to operate at normal atmospheric pressure and at a temperature of 100 degrees Celsius (212 Fahrenheit), requiring fewer complicated technical solutions and materials. Skoda explained that with the transition toward cleaner energies, there was now considerable interest in the concept and almost all of Czech energy companies with a heating division were open to further exploring the idea. "We are currently in the midst of concrete negotiations. We've also had meetings in Helsinki where authorities are thinking of converting the city's large-scale central heating system," he said.

The Teplator design does not yet have the required permits, but the team is searching for a site to build a first plant. "We are surprised by the positive reaction," said Skoda. "This is probably due to the fact that the acceptance of nuclear energy is quite high in the Czech Republic." Skoda hopes the first Teplator in the Czech Republic will be operating by 2028, but thinks it will take longer to be accepted in other EU countries.

According to the Teplator website, the facility would have a thermal power range of 50-200 MW. The construction investment cost is less than €30 million and the heating cost less than €4 per gigajoule at 2019 prices. “Using the heat produced in Teplator, we are lowering the environmental footprint. By implementing the idea of energy storage into the design, we can in fact ensure continuous heat supply to the customer. With the use of the spent fuel from conventional pressurized water reactors (PWRs) we ensure better utilisation of the nuclear fuel. Thanks to its design and size, Teplator can be sited at locations closer to end customers,” the website says.

It adds that the Teplator solution is especially suitable for countries that have thousands of fuel assemblies (FAs) stored either in interim storage casks or used fuel pools. “These FAs are now financial liability which, once used for heat production, can turn into a sizeable financial asset.”

There are several designs, but the Teplator Demo has the following features:

  • operates at atmospheric pressure
  • three loop heavy water design
  • three primary heat exchangers
  • three circulation pumps
  • 55 fuel elements in the core

The whole system comprises the Templator core and intermediary circuit with the possibility of including an energy storage system. The primary coolant, after leaving the fuel, enters the primary heat exchanger (HE I), where the heat is transferred to the inner circuit heat transfer fluid. This then transfers heat from the primary heat exchanger (HE I) via the inner circuit into the secondary heat exchanger (HE II), where heat enters the end user heating circuit.