Full length control rod employing axially inhomogeneous absorber materials for zero reactivity redistribution factor
A neutron absorber control rod for use in a fuel assembly of a nuclear reactor is described comprising: (a) an elongated hollow tubular member having opposite ends and a hermetically sealed chamber; (b) neutron absorber material pellets contained in the chamber and located nearer to the trailing than to the leading end of the member. Each of the pellets consist essentially of a neutron absorber material having a first neutron absorption cross section; (c) neutron absorber material pellets contained in the chamber and located nearer to the leading than to the trailing end of the member. Each of the pellets consist essentially of a neutron absorber material having a second neutron absorption cross section; (d) means located in the chamber between the trailing end of the member and the pellets for maintaining the pellets in stacked relation with and in abutting relation with the pellets to define a space within the chamber adjacent the trailing end of the member, the means maintaining the stack of pellets in substantially abutting relation with the end plug sealing the leading end; (e) the neutron absorber material of the first pellets having higher neutron absorption cross section than that of the neutron absorber material of the second pellets; (f) the length of the second neutron absorber material pellets in stacked relation with the first neutron absorber material pellets being greater than the length of the first neutron absorber material pellets; (g) the neutron absorber material pellets thereof having substantially the same as diameters; (h) the control rod consisting essentially of the hollow tubular member, the end plugs, the first neutron absorber material pellets, the neutron absorber material pellets, and the maintaining means.
- Assignee:
- Westinghouse Electric Corp., Pittsburgh, PA
- Patent Number(s):
- US 4699756
- OSTI ID:
- 5981457
- Resource Relation:
- Patent File Date: Filed date 8 Aug 1985
- Country of Publication:
- United States
- Language:
- English
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