About five decades ago the US Army built eight reactors, five of them portable or mobile. PM1 successfully powered a remote air/missile defence radar station on a mountain top near Sundance, Wyoming for six years to 1968, providing 1 MWe. At Camp Century in northern Greenland the 10 MWt, 1.56 MWe plus 1.05 GJ/hr PM-2A was assembled from prefabricated components, and ran from 1960-64 on high-enriched uranium fuel. Another was the 9 MWt, 1.5 MWe (net) PM-3A reactor which operated at McMurdo Sound in Antarctica from 1962-72, generating a total of 78 million kWh and providing heat. It used high-enriched uranium fuel and was refuelled once, in 1970. MH-1A was the first floating nuclear power plant operating in the Panama Canal Zone from 1968-77 on a converted Liberty ship. It had a 45 MWt/10 MWe (net) single-loop PWR which used low-enriched uranium (4-7%). It used 541 kg of U-235 over ten years and provided power for nine years at 54% capacity factor.
Construction of a larger version of the HTR-10, China's HTR-PM, was approved in principle in November 2005, with preparation for first concrete in mid-2011 and full construction start intended in December 2012. It is also based on the German HTR-Modul design of 200 MWt. Originally envisaged as a single 200 MWe (450 MWt) unit, this will now have twin reactors, each of 250 MWt driving a single 210 MWe steam turbine.*
FULL Fusion 360 2012 Portable
Another full-size HTR design is being put forward by Framatome (formerly Areva). It is based on the GT-MHR and has also involved Fuji. The reference design is 625 MWt with prismatic block fuel like the GT-MHR. Core outlet temperature is 750C for the steam-cycle HTR version (SC-HTGR), though an eventual very high temperature reactor (VHTR) version is envisaged with 1000C and direct cycle. The present concept uses an indirect cycle, with steam in the secondary system, or possibly a helium-nitrogen mix for the VHTR, removing the possibility of contaminating the generation, chemical or hydrogen production plant with radionuclides from the reactor core. It was selected in 2012 for the US Next Generation Nuclear Plant, with two-loop secondary steam cycle, the 625 MWt probably giving 285 MWe per unit, but the primary focus being the 750C helium outlet temperature for industrial application. It remains at the conceptual design stage.
The eVinci microreactor of 1 MWe to 5 MWe, but typically 1.6 MWe in present plans, would be fully factory built and fuelled. As well as power generation, process heat to 600C would be available. Units would have a 40-year lifetime with three-year refuelling interval. They would be transportable, with setup under 30 days. The units would have 'walk-away' safety due to inherent feedback diminishing the nuclear reaction with excess heat, also effecting load-following. There are multiple fuel options for the eVinci, including uranium in oxide, metallic and silicide form. LANL and INL are researching the fuel. Westinghouse is aiming to complete the design, testing, analysis and licensing to build a demonstration unit by 2022, test by 2023, and have the eVinci ready for commercial deployment by 2025. In March 2020 the US Department of Defense awarded a contract for further development of the design (see Military developments section above), possibly using TRISO fuel, as the defense-eVinci (DeVinci), but $11.9 million DOD funding went only to March 2021. In December 2020 the DOE selected Westinghouse for a cost-share project of $9.3 million over seven years (DOE share $7.4 million) to develop the eVinci microreactor with a view to having a demonstration unit by 2024. 2ff7e9595c