South African company plans to build HTMR-100 mini-stack


Stratek Global South Africa plans to build a high temperature modular reactor (HTMR-100) demonstration plant. The reactor design is derived from the South African PBMR programme.

The South African PBMR is a small high temperature reactor using triple isotropic cladding (TRISO) fuel and helium coolant for heat and power generation. The fuel characteristics provide the reactor with a high level of non-energetic safety.

South Africa has been working on the PBMR project since 1993, relying on proven German technology, but by 2010 the South African government announced that it was ceasing its investment in the project, which was then put on maintenance and care, mainly to retain its associated intellectual property and assets.

Kelvin Kemm, CEO of South Africa’s Stratek Global, said that the PBMR project was already in the early stages of its demonstration phase and that with the experience and assets inherited from the project, the first HTMR-100 reactor was expected to be built within five years. kemm highlighted that South Africa had already produced TRISO fuel for the HTMR-100 reactor.

Kemm describes the new 35 MWe class reactor as relatively small, with a footprint of less than a football field, and the TRISO fuel as robust and easy to transport over long distances or over rough roads. kemm claims that the design has low cooling water requirements and is particularly suitable for deployment in Africa, being able to supply power to remote mines and communities without the need to build long distance distribution grids. Apart from South Africa, other countries are interested in the design.

Kemm notes that the initial target market for the HTMR-100 is Africa, as well as further afield in the Pacific Rim and Asia. The company’s current focus is on South Africa’s 2,500 MWe nuclear energy programme, of which 100 MWe will come from small-scale reactors.

Stratek Global describes two main differences between the PBMR and the HTMR-100: firstly, the latter reduces the outlet gas temperature from 940°C to 750°C, which reduces some of the engineering requirements and makes the reactor more economical and competitive; secondly, the PBMR uses direct helium circulation through the reactor to the turbine, while the HTMR-100 directs heat into the water heat exchanger or steam generator, which in turn generates steam to drive the steam turbine or produce process heat. The advantage of the latter is that all equipment downstream of the heat exchanger has been purchased off-the-shelf, significantly reducing the time and cost of secondary equipment design and development.

With two 900 MWe class units, the Koeberg nuclear power plant of the South African National Power Corporation is the only nuclear power plant in operation in Africa and supplies approximately 5% of South Africa’s electricity. The two units, which were connected to the grid in 1984 and 1985 respectively, have an initial operating licence of 40 years and have been granted a 20-year life extension until 2045.

In May 2023, South African Energy and Mines Minister Gwede Mantashe said that the South African government planned to issue procurement documents for a 2,500 MWe nuclear energy development project in the fourth quarter of 2023.


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