About Steenkampskraal Thorium (Pty) Limited (STL Nuclear)

Steenkampskraal Thorium (Pty) Limited (STL Nuclear) is a privately owned company with a vision to provide clean, sustainable and safe energy to the world through the development and commercialization of Thorium as a fuel source.

STL Nuclear owns:

• A concept design of the HTMR-100 (100 MWthermal ,35 MWelectircal) pebble bed reactor. The HTMR-100 is a high temperature gas-cooled reactor (HTGR) with a thorium-based fuel cycle.

Steenkampskraal Thorium (STL Nuclear) has embarked on a project to produce clean, safe, economical and accessible energy to a wide range of energy consumers. This project is known as the Thorium-100 Nuclear Power Plant (HTMR-100 NPP). The HTMR-100 NPP is an inherently safe, modular pebble bed type reactor that burns thorium as fuel and produces less and more acceptable waste compared to other nuclear power generation technologies. The HTMR-100 NPP can be constructed in a relatively short time at almost any location. It is predicted that the inherent safety features of the reactor simplify the licensing process significantly compared to other nuclear power generation technologies.

Thorium as a nuclear fuel is becoming increasingly important to meet the world’s energy demands (Thorium is three to four times more abundant than uranium in the earth’s crust). HTMR-100 NPP will utilize ThO2 fuel with high burn-up rates and has great proliferation advantages in the sense that it produces very little or no Pu-239. The reactor design can accommodate various fuel types with different fuel cycles, including mixtures of thorium and plutonium or thorium and uranium. For example, the thorium/plutonium fuel mix can be utilized to reduce the world’s stockpiles of plutonium by incinerating it in this reactor.

The HTMR-100 NPP can be constructed inland due to limited tritium production. Furthermore, the favorable economic feasibility, short licensing process, ease of operation as well as the modular construction design, makes it a strong contender in the energy sector. The HTMR-100 NPP can serve as a base load power supplier but have relative good load following characteristics and is therefore ideally suited as a remote standalone power plant. The HTMR-100 NPP features an indirect steam cycle and can therefore be used for driving a steam turbine, supply steam for industrial process heat applications as well as cogeneration applications.

The thorium-based High Temperature Gas cooled Reactor (HTGR) technology was chosen for the HTMR-100 NPP due to the following considerations:

• The HTMR-100 reactor is intrinsically safe because its core is meltdown-proof. This characteristic ensures that the HTMR-100 NPP can withstand a Fukushima-type incident.
• The HTMR-100 reactor addresses the risk of nuclear weapons proliferation due to the fact that:
  • its thorium fuel cycle does not produce plutonium as used in nuclear weapons;
  • it can reach high burn-up rates which fully utilizes fissile material in the reactor
• The HTMR-100 reactor will produce less hazardous nuclear waste, which benefit waste management problems.
• The HTMR-100 concept is economically attractive compared to other nuclear technologies due to its advanced design features:
  • Modularity reduces construction period;
  • System standardization and design simplicity create upstream economies of scale; and
  • Reduced number of required safety functions/systems reduces costs.
• Security of fuel supply is guaranteed, since thorium is 4 times more abundant than uranium as mentioned above.
• The HTMR-100 NPP is a CO2 emissions free source of base-load power with high availability and suitable for distributed generation.
• Steenkampskraal Thorium Limited already owns the right to significant thorium reserves in South Africa and therefore aims to commercialise a thorium-based High Temperature Gas Cooled Reactor (HTGR)

Previous studies showed that the smallest economically viable HTGR- NPP, is 70 to 100 MWth. For this reason, the HTMR-100 NPP was designed as a 100 MWth unit, with corresponding electricity production of 35 MWe. In addition, the majority of the electrical grids in the world today cannot accommodate large power sources, which caused the demand for smaller power sources to increase significantly. The HTMR-100 is therefore ideally suited to be used as a standalone plant or in groups of module (multi-module plant). Initially the HTMR-100 NPP will probably serve a niche market where small to medium power sources are required, such as small communities or remote industries like mines or smelters, etc.

The design philosophy of the HTMR-100 NPP can be described as simplification and optimization of proven technology within acceptable safety criteria. The designers therefore aimed to lower plant costs and improve reliability rather than optimizing the thermal efficiency of the process. The European nuclear safety principles in combination with USA requirements were provisionally adapted as design basis for the HTMR-100 NPP.

The following design criteria have been followed in the HTMR-100 NPP design:

1. Simplicity
2. Multiple defence levels
3. Factory manufacturing as far as practicable/possible
4. Simple operation
5. Ease of maintenance
6. Safety design for external events such as earthquakes, airplane crashes, etc.

The HTMR-100 NPP project aims to design, license and construct the first plant in the next 5 years.