Accelerator driven thorium power plant

Aker Solutions has conceptually designed an accelerator-driven thorium reactor 600 MWe power station, an accelerator driven, thorium-fuelled, lead-cooled fast reactor. The accelerator would add 10% to the cost but would allow for other systems to be cheaper. The accelerator-driven thorium reactor can burn waste actinides generated in uranium-fuelled reactors, providing sustainable energy for future civilisation. Choosing a sub-critical accelerator-driven system provides safe operating margins for the thorium fuel cycle. The proposed reactivity coefficient of 0.995 allows selection of an industrial-scale accelerator with commercial benefits which led to a novel solution for measurement and control of reactivity.

Virtually all thorium mined can potentially be used as fuel, compared with uranium that requires expensive enrichment processes resulting in significant quantities of depleted uranium waste. In energy equivalent terms, 1 ton of mined thorium is equivalent to 200 ton of mined uranium, which is equivalent to 3.5 million tonnes of mined coal.

Half of initial 15.5% plutonium content of the ADTR is burnt in the first 10-year fuel cycle. This equates to 0.46 tons of plutonium consumed per annum per reactor loaded with 59 tons of fuel. Current pressurised water reactor (PWR) designs produce approximately 1% plutonium in a 3-year fuel cycle thereby manufacturing 0.33 tons per year from a typical 100 tons fuel load. So one ADTR can consume plutonium production of approximately 1.4 uranium fuelled PWRs. This reduction in plutonium is far more efficient than the MOX fuel solution currently in place. A typical MOX fuel will contain less than half the 15.5% plutonium loading of the ADTR and only consume 30% of this plutonium loading per cycle as compared with 50% for the ADTR.

The study has demonstrated technical feasibility of the ADTR design. To be a viable business opportunity, ‘time to market’ for the first operational ADTR power station is planned for 2030 which is in line with Generation IV reactors. This timescale is made more realistic owing to use of a relatively small accelerator of established design, together with application of existing technologies throughout the design plus Jacobs’ ability to deliver large capital projects to clients in the global energy market.

A fundamental development of the ADTR has been the challenge to previously established margins to criticality. The
proposed keff of 0.995 was influenced by the selection of an accelerator based on commercial considerations. Subsequent
analysis of the system neutronics and safety has led to a wholly novel solution for measurement and control of reactivity.

The next stage, requiring significant investment, will underpin ADTR technology with development programmes and progression of engineering. It is essential that physical testing commences to provide empirical data necessary for the designand to prove physical aspects of the design.

It will take £2bn to build the first one, and Aker needs £100mn for the next test phase.

The Telegraph UK has proposed a Manhattan project effort to develop a viable thorium commercial reactor within 3-5 years. They did talk about ending dependence upon fossil fuels in 3 to 5 years but a first thorium commercial reactor would not do that. A transition away from fossil fuels would still take decades even if a thorium commercial reactor was already working. The fuel cycle has to get built up and massive factories and supply chains would need to be created. I do not see how the accelerator driven thorium reactor would be the best choice as a thorium reactor to scale up for fossil fuel displacement. It should be a smaller modular reactor with easy mass production capabilities.

I would choose several of the molten salt reactor designs.