High temperature reactors for energy-neutral mineral extraction

Tuesday, 24 July 2018

As global demand for mineral commodities including phosphates, copper and rare earth elements increases, easily extractable resources become depleted and global production shifts to lower-grade or unconventional resources. Such ores may also contain significant amounts of uranium and other potentially valuable minerals. Energy neutral mineral processing aims to recover these unconventional uranium resources as a byproduct of primary ore processing, and use them to generate energy in a nuclear reactor.

Energy neutrality is reached if the energy produced from the extracted uranium is equal to or larger than the energy required for primary ore processing, uranium extraction, conversion, enrichment and fuel production. The extraction of naturally occurring radioactive materials, also known as NORM, which occurs alongside the extraction of byproduct uranium, also results in cleaner end-products (such as phosphoric acid for fertilisers) and tailings.

The IAEA's coordinated research project (CRP), Uranium/Thorium Fuelled High Temperature Gas Cooled Reactor Applications for Energy Neutral and Sustainable Comprehensive Extraction and Mineral Product Development Processes, was established in 2015 and involves 17 institutes from 16 of the agency's member states. The group's first results were published earlier this year in the academic journal Sustainability, and a comprehensive IAEA Technical Document is to be published next year.

The CRP participants have studied a variety of ores, determining the content of uranium and thorium - which could also potentially be used in the future for energy generation - and testing different extraction processes. Project modelling of the coupled system consisting of HTRs and mineral processing plants has been carried out at the IAEA. The research shows how using heat and electricity from a small and modular high temperature reactor, built near the mineral processing plant, to process the raw material might offer a feasible route to producing enough uranium byproduct to be energy neutral.

"Using reliable, inexpensive and greenhouse gas lean power from nuclear reactors for mineral development at processing centres but particularly at remote location is something the minerals processing industry long dreams of," the CRP's scientific secretary Frederik Reitsma, who also leads IAEA's gas cooled reactor technology development activities, said.

High-temperature gas cooled reactors have operated as research and prototype reactors since the 1960s and two such research reactors are currently in operation: Japan's HTTR, in operation since 1998; and China's HTR-10, since 2000. A two-unit demonstration plant, HTR-PM, is under construction at Shidaowan in China's Shandong province and is expected to begin generating electricity this year.

CRPs are an important IAEA mechanism for organising international research work to achieve specific research objectives consistent with the IAEA programme of work, with the results of the projects made freely available to scientists, engineers and other users from all Member States.