Prism is a sodium-cooled fast neutron reactor design built on more than 30 years of development work, benefitting from the operating experience of the EBR-II prototype integral fast reactor which operated at the USA's Idaho National Laboratory - formerly Argonne National Laboratory - from 1963 to 1994. According to GEH, the testing, design and operational experience underlying Prism makes the design well positioned to continue the licensing process.
Each Prism reactor has a rated thermal power of 840 MW and an electrical output of 311 MW. Two Prism reactors make up a power block, producing a combined total of 622 MW of electrical output. Using passive safety, digital instrumentation and control, and modular fabrication techniques to expedite plant construction, the design uses metallic fuel, such as an alloy of zirconium, uranium, and plutonium. It can therefore be used to close the nuclear fuel cycle, recycling used nuclear fuel to generate energy.