My recent posts have been about breeder reactors which generate more fissile material than they consume. There is renewed interest in breeder reactors for the production of nuclear fuel and the destruction of nuclear waste. Today I am going to delve into the history of breeder reactors in the United States.
Scientists who worked on the first atomic bombs for the U.S. military during World War II considered the availability of uranium and decided that there needed to be a better way to obtain plutonium for future weapons. They developed the theory of breeder reactors where more fissile material could be created than was burned by the reactor.
The first fast neutron breeder reactor in the world was called Clementine. It was cooled with mercury. Construction started at Los Alamos in 1946 and the reactor went into full production in 1949. Plutonium metal was inserted into steel rods with natural uranium slugs as end caps. A set of rods were placed in a cage with mercury circulating between the rods. There was a shell of natural uranium around the core to act as a reflector. Clementine was shut down in 1950 because of a control rod malfunction. It was fixed and restarted but then a fuel rod exploded. It was subsequently dismantled.
Concerned with the danger of building experimental nuclear reactors near population centers, the U.S. government opened a new nuclear laboratory called the Nuclear Reactor Testing Station near Arco, Idaho. The Experimental Breeder Reactor I (EBR-1). The ERB-I used sodium-potassium as a coolant. They had to be very careful that there were no leaks because the coolant would spontaneously burst into flame if it came into contact with water or air. It was fueled with uranium enriched to ninety four percent U-235. The EBR-I went into operating in 1951 and was the first reactor to generate electricity. As the power output was increased, the reaction increase creating a positive feedback loop. During tests in 1955, forty percent of the core melted down. The reactor was repaired and operated until 1963.
Admiral Hyman Rickover initiated research on fast neutron reactors for submarine propulsion. The S1G was built by General Electric at the Knolls Atomic Laboratory in New York state. It was fuel with highly enriched uranium and began operating in 1955. It had problems with leaks in its steam turbine system and was shut down in 1957. Rickover dropped the idea of fast neutron reactors for submarine propulsion citing the turbine problem, the complexity and the expense of such reactors.
LAMPRE-I was built at Los Alamos. It was fueled with molten plutonium and was cooled with sodium. It began operating in 1961 and ran until 1963. The operating level had to be reduced because the researched found that they did not know enough about the temperatures that would be generated. It was shut down and funding for a more advanced design never materialized.
Clementine, the world's first fast breeder reactor:
