 South Africa’s Pebble Bed Modular Reactor (PBMR) company has signed a Memorandum of Understanding (MoU) with its Chinese counterparts, the Institute of Nuclear and New Energy Technology (INET) of Tsinghua University and the Chinergy company. INET and Chinergy are also developing PBMR technology.
The MoU is intended to encourage cooperation in specific areas of common interest, both strategic and technical, concerning both countries’ PBMR projects, to create opportunities regarding the commercialisation of the technology in the future, and to reinforce the supply chains in both countries.
PBMR technology was originaly developed in Germany and subsequently licensed to both South Africa and China, each country further developing the concept, although in somewhat (but not fundamentally) different directions.
The Chinese, unlike the South Africans, actually have an operational PBMR reactor, although it is only a small – 10 MW (thermal) – research unit. Located at INET in Beijing, it is the only operational PBMR in the world, and was started in December 2000, achieving full power in January 2003.
The main difference between the two PBMR projects is that the Chinese will use an indirect cycle, steam turbine system for their commercial-scale demonstration plant, while the South Africans have been developing a direct cycle, gas turbine system.
The Chinese demonstration plant will comprise two 250 MW (thermal) reactor modules and a 210 MW (electric) steam turbine generator set.
However, recently, the South Africans have started developing technology for indirect cycle, steam turbine systems, as a result of increasing interest in process heat and co-generation applications for the PBMR.
This means that the South African programme is now converging with the Chinese, creating more synergies between them. This became very clear at an international high temperature reactor (HTR) conference in Washington, DC, in December.
This was followed, earlier this year, by a visit to South Africa by representatives of INET and Chinergy, who, with their local counterparts, worked out the framework for cooperation.
The PBMR is an HTR design and is so named because its fuel is in the form of spheres. These take the form of enriched uranium oxide coated with silicon carbide and pyrolytic carbon, in turn encased by graphite. The resulting sphere is about the size of a billiard ball.
A fully-loaded PBMR reactor core would contain some 450 000 fuel spheres. Because of its design and and the nature of its fuel, it will be possible to remove spent fuel spheres from the bottom of the PBMR, and feed fresh fuel spheres in at the top, while the reactor is running.
In other designs, the reactor has to be shut down for refuelling to take place.
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