Patent Number: 041585992
Section: abstract

There is disclosed a method for rapid refueling of a nuclear reactor. The upper package including the head and upper internals and control rods of the reactor includes a missile shield and by engagement with the shield is moved to a refueling position in a single lifting operation exposing the core in the lower package. The fuel assemblies are then replaced. The removal of the control rods from the core with the upper package is compensated for by an increase in the concentration of neutron absorber, such as boron including B.sup.10, in the medium in which the core is immersed. Typically, the refueling can take place in a few days, at intervals of two to six months. During refueling a fraction of the assemblies are replaced. Because of the facility for rapid refueling and consequent lower time cycle for refueling, the fuel can be of low enrichment and the concentration of neutron absorber in the reactor coolant medium can be decreased. All replacement assemblies can be moved in a cart into the reactor containment in a single operation and replaced from the cart, or the assemblies can be moved one-by-one into the containment and replaced as they are presently.