Aqueous homogeneous reactor

Their self-controlling features and ability to handle very large increases in reactivity make them unique among reactors, and possibly safest.

It pained chemists to see precisely fabricated solid-fuel elements of heterogeneous reactors eventually dissolved in acids to remove fission products—the "ashes" of a nuclear reaction.

Chemical engineers hoped to design liquid-fuel reactors that would dispense with the costly destruction and processing of solid fuel elements.

The name was appropriate because in the higher power versions the fuel solution appeared to boil as hydrogen and oxygen bubbles were formed through decomposition of the water solvent by the energetic fission products, a process called radiolysis.

LOPO served the purposes for which it had been intended: determination of the critical mass of a simple fuel configuration and testing of a new reactor concept.

By 1950 higher neutron fluxes were desirable, consequently, extensive modifications were made to HYPO to permit operation at power levels up to 35 kilowatts.

In 1952, two sets of critical experiments with heavy water solutions of enriched uranium as uranyl fluoride were carried out at Los Alamos to support an idea of Edward Teller about weapon design.

In the other set of experiments solution spheres were centered in a 35-inch diameter (890 mm) spherical container into which D2O was pumped from a reservoir at the base.

The reactor's high-pressure steam twirled a small turbine that generated 150 kilowatts (kW) of electricity, an accomplishment that earned its operators the honorary title "Oak Ridge Power Company."

The reactor in the Kurchatov Institute, with 20 kW thermal output power, has been in operation since 1981 and has shown high indices of efficiency and safety.

The ability to extract medical isotopes directly from in-line fuel has sparked renewed interest in aqueous homogeneous reactors based on this design.

Atomics International designed and built a range of low power (5 to 50,000 watts thermal) nuclear reactors for research, training, and isotope production purposes.

One reactor model, the L-54, was purchased and installed by a number of United States universities and foreign research institutions, including Japan.