Bow control for metallic structures
AssigneeGeneral Electric Company
InventorFletcher C. Eddens
Life of this patent
Estimating the term…
Abstract
A method of controlling the bowing action of fuel channels used in nuclear reactor cores is disclosed. Each channel is heat treated and mounted in its control rod module with an orientation dependent on its prior heat treatment. Upon exposure to radiation, the channels will bow in a desired direction away from the control rod.
Claims9
A method of controlling the bowing action of at least one elongate zirconium structure including opposite ends, adapted for vertical positioning, said bowing action occurring upon the expansion due to external factors upon said mounted structure;
- said method comprising the steps of:
- heat treating said structure prior to mounting, said heat treatment including heating a full length portion of said structure to a temperature in the beta range and the remainder of said structure at a temperature below the beta range, said heat-treated full-length structure portion being adapted to expand at a different rate than the remainder of said structure such that bowing due to said external factors occurs substantially only in a predicted direction;
- and
- securing said heat-treated structure at its opposite ends in a manner whereby bowing in said predicted direction is capable of taking place without interference with other nearby structures.
A method of controlling the bowing action of a plurality of hollow, axially elongate channels of an alloy of zirconium each adapted to be rigidly mounted at their opposite ends as part of a four-channel module, each of said channels having four walls and a generally square cross section, a full-length control rod having a substantially cruciform cross section separating respective channels from each other in said module and positioned in spaced relationship to said channels;
- said method comprising the steps of:
- positioning each of said channels within an induction heating coil with the centers of said channel and said coil displaced from each other such that one pair of adjacent channel walls is more closely coupled to said coil than the opposite pair of adjacent walls;
- passing said positioned channel through said coil in an axial direction;
- heating said one pair of adjacent walls to the beta range while simultaneously heating said opposite pair of adjacent walls to the alpha-plus-beta range;
- and
- mounting each of said channels in its module with said one pair of walls positioned closer to said control rod than said opposite wall pair.
Dependencies are inferred from the claim text.