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To reduce the concentration of Pu-240 in the plutonium produced, weapons program plutonium production reactors (e.g. B Reactor) irradiate the uranium for a far shorter time than is normal for a nuclear power reactor. More precisely, weapons-grade plutonium is obtained from uranium irradiated to a low burnup.
The first time gun-type fission weapons were discussed was as part of the British Tube Alloys nuclear bomb development program, the world's first nuclear bomb development program. [1] The British MAUD Report [ 2 ] of 1941 laid out how "an effective uranium bomb which, containing some 25 lb of active material, would be equivalent as regards ...
The two fissile materials used in nuclear weapons are: 235 U, also known as highly enriched uranium (HEU), "oralloy" meaning "Oak Ridge alloy", [12] or "25" (a combination of the last digit of the atomic number of uranium-235, which is 92, and the last digit of its mass number, which is 235); and 239 Pu, also known as plutonium-239, or "49 ...
The pits of the first nuclear weapons were solid, with an urchin neutron initiator in their center. The Gadget and Fat Man used pits made of 6.2 kg of solid hot pressed plutonium-gallium alloy (at 400 °C and 200 MPa in steel dies – 750 °F and 29,000 psi) half-spheres of 9.2 cm (3.6 in) diameter, with a 2.5 cm (1 in) internal cavity for the initiator.
This was a natural-uranium fuelled, heavy-water moderated and cooled research reactor (converted to high-enriched-uranium fuel in the 1960s, and finally to low-enriched-uranium fuel in the 1990s). The NRU is a world-renowned research facility, producing about 60% of the world's supply of molybdenum-99, the principle isotope used for nuclear ...
Plutonium-239 is the primary fissile isotope used for the production of nuclear weapons, although uranium-235 is also used for that purpose. Plutonium-239 is also one of the three main isotopes demonstrated usable as fuel in thermal spectrum nuclear reactors , along with uranium-235 and uranium-233 .
Apr. 14—It's been almost 80 years since the first atomic bomb was detonated, and scientists say there's still much to learn about how nuclear devices function as they reach the point of ...
Reactor-grade plutonium (RGPu) [1] [2] is the isotopic grade of plutonium that is found in spent nuclear fuel after the uranium-235 primary fuel that a nuclear power reactor uses has burnt up. The uranium-238 from which most of the plutonium isotopes derive by neutron capture is found along with the U-235 in the low enriched uranium fuel of ...