The Th-100 nuclear plant power source is a 100 MWth high temperature helium cooled pebble bed reactor. It features a Once-Through-Then-Out (OTTO) Thorium fuel cycle, thereby simplifying the layout, whilst simultaneously enhancing the proliferation resistance characteristics by performing an in-situ burn up of the produced fissile plutonium isotopes. The Th-100 produces high quality steam and is therefore versatile for various applications. Steam can be used for producing power via a steam turbine (35MWe), or it can be used for process heat in petrochemical plants, oil refineries and many other applications. In the future, high temperature heat can be supplied via an intermediate gas-to-gas heat exchanger; development of such a heat exchanger is to be undertaken.
The Th-100 exhibits the following excellent characteristics:
- Fully ceramic fuel elements, which cannot melt, even in extreme accidents which may result in the total loss of active core cooling;
- Use of coated thorium fuel particles (TRISO) effectively retaining the fission products within the fuel and allowing for very high burn-up of the fuel;
- Use of helium as coolant, which is both chemically and radiologically inert and does not influence the neutron balance. It allows for very high coolant temperatures during normal operation.
- Use of fully ceramic (graphite) core internal structures, which enables operation at high temperatures;
- A reactor core with a low power density, providing a thermally robust design with a high heat capacity renders the reactor thermally stable during all operational and control procedures;
- The reactor core can tolerate a loss of forced cooling event. Passive decay heat removal is possible and fuel temperatures stay below admissible values. Therefore, the fission products remain inside the fuel particles even in extreme accidents.
- Very strong negative temperature coefficients contribute to the excellent inherent safety characteristic of these reactors;
- Efficient retention of fission products in the coated particle fuel in normal operation allows for a clean
helium circuit; resulting in low levels of contamination of the coolant gas, low release of radioactivity,
and extremely low radiation dose values to the operation staff;
- Efficient retention of fission products in the coated particles under extreme accidents results in a reactor without catastrophic release to the environment under these conditions.