Search results
Results from the WOW.Com Content Network
In the event of a loss-of-coolant accident in a PWR, the moderator is also lost and the reaction will stop. This negative void coefficient is an important safety feature of these reactors. In CANDU the moderator is located in a separate heavy-water circuit, surrounding the pressurized heavy-water coolant channels.
A pressurized water reactor (PWR) is a type of light-water nuclear reactor. PWRs constitute the large majority of the world's nuclear power plants (with notable exceptions being the UK, Japan, India and Canada). In a PWR, water is used both as a neutron moderator and as coolant fluid for the reactor core.
These elements have different neutron capture cross sections for neutrons of various energies. Boiling water reactors (BWR), pressurized water reactors (PWR), and heavy-water reactors (HWR) operate with thermal neutrons, while breeder reactors operate with fast neutrons. Each reactor design can use different control rod materials based on the ...
A neutron moderator is a medium which reduces the velocity of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235. A good neutron moderator is a material full of atoms with light nuclei which do not easily absorb neutrons. The neutrons strike the nuclei and bounce off.
Print/export Download as PDF; Printable version; In other projects ... Pages in category "Neutron moderators" The following 9 pages are in this category, out of 9 ...
Almost all currently operating nuclear power plants are light water reactors using ordinary water under high pressure as coolant and neutron moderator. About 1/3 are boiling water reactors where the primary coolant undergoes phase transition to steam inside the reactor. About 2/3 are pressurized water reactors at even higher pressure.
BWR allow lower primary coolant flow than PWR. [clarification needed] Jet pumps internal to the reactor vessel provide 2/3rds of the recirculation flow, allowing the external recirculation flow loop to be small and compact compared to contemporary PWR designs. Under loss of coolant jet pumps provide 10% power similar to boilers.
The Reduced-Moderation Water Reactor (RMWR), also referred to as the Resource-renewable BWR, is a proposed type of light water moderated nuclear power reactor, featuring some characteristics of a fast neutron reactor, thereby combining the established and proven technology of light water reactors with the desired features of fast neutron reactors.