About Us
Who is STL?
STL Nuclear is a privately owned nuclear technology company based in the Northern suburbs of Pretoria whose core focus is directed towards Generation IV nuclear reactor technology.
STL Nuclear have built up a core team of technical specialists (fuel & reactor) who have successfully risen to the challenge of designing and building nuclear reactor and fuel plant technologies and have to date completed 10 years of engineering on a 100MWth high-temperature modular gas-cooled reactor (HTMR) with the objective of providing cleaner, safer, sustainable and affordable nuclear power and desalination.
STL Nuclear were contracted by a US firm to develop first of a kind HTR fuel elements based on the U.S. Department of Energy (DOE) Advanced Gas Reactor (AGR) program for UCO TRISO fuel. The fuel data design package as well as a pilot plant for fuel production. This fuel development project is being commissioned by the U.S. company to accelerate the development of an innovative new nuclear technology.
STL Nuclear are also currently busy with a TRISO fuel plant design to fabricate fuel compacts for a European Client.
In addition, STL Nuclear are busy with a feasibility study to supply another TRISO fuel pilot plant to a US customer to produce fuel compacts.
STL Nuclear Owns:
A Basic design of the HTMR100 (100 MW thermal, 35 MW electrical) pebble bed reactor. The HTMR-100 is a high temperature gas-cooled reactor (HTGR) with a thorium or uranium-based fuel cycle and a detailed design of a laboratory, pilot and industrial scale fuel manufacturing facilities producing pebble and compact type fuel.
STL also owns a facility where fuel production equipment is manufactured, erected, assembled and commissioned. The Laboratory can also demonstrate Kernel manufacture using surrogate materials and investigate graphite powder properties for pebble or compact manufacture. The Laboratory also serves as a process development area to develop new and innovative ways of improving the manufacturing steps for TRISO fuel towards commercialisation.
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:
- Simplicity
- Multiple defence levels
- Factory manufacturing as far as practicable/possible
- Simple operation
- Ease of maintenance
- 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.
David Boyes
Managing Director (STL Nuclear)David Boyes completed his Baccalaureus Technologiae in Metallurgical Engineering and has over 30 years of nuclear fuel process development and fuel manufacturing experience. David started work at the then Atomic Energy Corporation where he developed uranium dioxide pellet fuel for Koeberg Nuclear Power station. This involved the research and development of the powder metallurgical route to fabricate fuel on an industrial scale for Koeberg.
He then became Production Manager of the uranium powder production plant and the uranium chemical recovery plant at the Nuclear Energy Corporation of SA. He then joined PBMR and produced the first uranium dioxide kernels for pebble fuel. He was responsible for all the uranium process facilities needed for the manufacture of pebble fuel at PBMR.
He now serves as managing director on the STL board overseeing the engineering design of a HTMR -100 reactor and is responsible for the development and supply of qualified pebble fuel for the reactor.
Professor Johan Slabber
Chief Technology Officer (STL Nuclear)Professor Johan Slabber is currently working in the Department of Mechanical and Aeronautical Engineering at the University of Pretoria where he is appointed to represent the University in all formal communications with the Director of the Centre for Nuclear Safety and Security (CNSS) of the National Nuclear Regulator (NNR). He is also involved in teaching and research in the field of Nuclear Engineering at both undergraduate and post-graduate levels. Before joining the University, he was the Chief Technology Officer at the company PBMR (Pty) Ltd.
In his earlier career he held the positions of General Manager, Reactor Technology at the Atomic Energy Corporation of South Africa (now Necsa), Chief Systems Engineer at the company Integrators of Systems Technology (IST) where he led a small team which completed the first conceptual systems design of a small Demonstration High Temperature Reactor. In 1994 he joined the Safeguards Department of the International Atomic Energy Agency (IAEA) in Vienna where he completed a contract period of 5 years before joining the company PBMR (Pty) Ltd in 1999.
He is a former member of the International Nuclear Safety Group (INSAG) of the IAEA and is currently the South African representative on the Senior Industry Advisory Panel (SIAP) of the Generation IV Industrial Forum (GIF) as well as a member of the Collaborative Research Group on Accident Tolerant Fuel (CARAT).
He holds a Doctorate in Mechanical Engineering from the University of Pretoria and also studied at the Oak Ridge School of Reactor Technology in the United States.