Search results
Results from the WOW.Com Content Network
Criticality accidents are divided into one of two categories: Process accidents, where controls in place to prevent any criticality are breached;; Reactor accidents, which occur due to operator errors or other unintended events (e.g., during maintenance or fuel loading) in locations intended to achieve or approach criticality, such as nuclear power plants, nuclear reactors, and nuclear ...
The demon core (like the core used in the bombing of Nagasaki) was, when assembled, a solid 6.2-kilogram (14 lb) sphere measuring 8.9 centimeters (3.5 in) in diameter.. It consisted of three parts made of plutonium-gallium: two hemispheres and an anti-jet ring, designed to keep neutron flux from "jetting" out of the joined surface between the hemispheres during implosi
The aircraft wreckage and the site of the accident were contaminated after a limited explosion of non-nuclear material. [45] December 30, 1958 Los Alamos, New Mexico, US Accidental criticality During chemical purification, a critical mass of a plutonium solution was accidentally assembled at Los Alamos National Laboratory.
The plutonium, dissolved in an organic solvent, flowed into the center of the vortex. Due to a procedural error, the mixture contained 3.27 kg of plutonium, which reached criticality for about 200 microseconds. Kelley received 3,900 to 4,900 rad (36.385 to 45.715 Sv) according to later estimates.
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.
The machine will be housed 1,000 feet underground at the Nevada National Security Site, formerly known as the Nevada Test Site, and will have a 400-foot-long accelerator, made up of 102 cells ...
A nuclear criticality accident occurs from operations that involve fissile material and results in a sudden and potentially lethal release of radiation. Nuclear criticality safety practitioners attempt to prevent nuclear criticality accidents by analyzing normal and credible abnormal conditions in fissile material operations and designing safe ...
The critical mass for lower-grade uranium depends strongly on the grade: with 45% 235 U, the bare-sphere critical mass is around 185 kilograms (408 lb); with 19.75% 235 U it is over 780 kilograms (1,720 lb); and with 15% 235 U, it is well over 1,350 kilograms (2,980 lb). In all of these cases, the use of a neutron reflector like beryllium can ...