The Molten-Salt Reactor Experiment (MSRE) was an experimental molten-salt nuclear reactor at the Oak Ridge National Laboratory (ORNL) researching this technology through the 1960s; constructed by 1964, it went critical in 1965 and was operated until 1969.
The MSRE was a 7.4 MWth test reactor simulating the neutronic “kernel” of a type of inherently safe epithermal thorium breeder reactor called the Liquid fluoride thorium reactor. It used three fuels: plutonium-239, uranium-235 and uranium-233. The last, 233UF4 was the result of breeding from thorium. Since this was an engineering test, the large, expensive breeding blanket of thorium salt was omitted in favor of neutron measurements.
In the MSRE, the heat from the reactor core was shed via a cooling system using air blowers and radiators. It is thought similar reactors could power high-efficiency heat engines such as closed-cycle gas turbines.
The MSRE’s piping, core vat and structural components were made from Hastelloy-N and its moderator was a pyrolytic graphite core. The fuel for the MSRE was LiF-BeF2-ZrF4-UF4 (65-30-5-0.1), the graphite core moderated it, and its secondary coolant was FLiBe (2LiF-BeF2), it operated as hot as 650 °C and operated for the equivalent of about 1.5 years of full power operation.
The result promised to be a simple, reliable reactor. The purpose of the Molten-Salt Reactor Experiment was to demonstrate that some of the key features of the proposed molten-salt power reactors could be embodied in a practical reactor that could be operated safely and reliably and be maintained without excessive difficulty. For simplicity, it was to be a fairly small, one-fluid (i.e. non-breeding) reactor operating at 10 MW(t) or less, with heat rejection to the air via a secondary (fuel-free) salt.
Graffiti artists said to be from Germany and Belarus have gone round the town of Pripyat drawing silhouettes of the missing population.
Operation Sea Orbit: On 31 July 1964, USS Enterprise (CVAN-65) (bottom), USS Long Beach (CGN-9) (center) and USS Bainbridge (DLGN-25) (top) formed “Task Force One,” the first nuclear-powered task force, and sailed 26,540 nmi (49,190 km) around the world in 65 days. Accomplished without a single refueling or replenishment, “Operation Sea Orbit” demonstrated the capability of nuclear-powered surface ships.
Chernobyl in Pictures
Last year, on the 25th anniversary of the meltdown at Chernobyl, NewsHour science correspondent Miles O’Brien visited Chernobyl to see what life is like there now.
See the pictures from his visit and watch his report on the PBS NewsHour site.