Abstract 1. In a nuclear reactor, the reactor including a pressure vessel with a fuel assembly disposed therein and means for circulating a coolant under pressure through the vessel, the fuel assembly comprising a plurality of fuel elements containing fissionable material, an improved control system comprising: a plurality of guide tubes for movable neutron absorber elements extending through the fuel assembly, said guide tubes terminating within the pressure vessel; upper end filtering means, the upper end of each guide tube being terminated in said upper end fitting means, said upper end fitting means including a tubular extension for each guide tube, the upper end of said tubular extensions defining valve seats; buffer means positioned in the pressure vessel above and axially aligned with each of said end fitting means tubular extensions; tubular hydraulic cylinder defining means extending between the upper end of each of said tubular extensions and said buffer means; actuator piston means disposed for movement in each of said tubular cylinder defining means, each of said actuator piston means having an upper surface cooperating with said buffer means for valving action and a lower surface cooperating with said upper end fitting means defined valve seat to perform a valving action; neutron absorber element means disposed for movement in each of the guide tubes; means mechanically coupling each of said actuator piston means to associated absorber element means whereby the absorber element means may be moved relative to the fuel elements; means located externally of the pressure vessel for generating a control pressure; a plurality of control lines penetrating the pressure vessel, said control lines being commensurate in number with the actuator piston means and extending from said control pressure generating means to respective of said control pressure to the upper surfaces of said actuator piston means; valve means disposed in each of said control lines for selectively applying said control pressure to said hydraulic cylinder defining means through said buffer means to said upper surface of said actuator piston means whereby said absorber elements may be individually adjusted between positions commensurate with full insertion into and full retraction from the fuel assembly; and means for applying the pressure vessel internal coolant pressure to the lower surfaces of said actuator piston means.
In a nuclear reactor, the reactor including a pressure vessel with a fuel assembly disposed therein and means for circulating a coolant under pressure through the vessel, the fuel assembly comprising a plurality of fuel elements containing fissionable material, an improved control system comprising: a plurality of guide tubes for movable neutron absorber elements extending through the fuel assembly, said guide tubes terminating within the pressure vessel; upper end filtering means, the upper end of each guide tube being terminated in said upper end fitting means, said upper end fitting means including a tubular extension for each guide tube, the upper end of said tubular extensions defining valve seats; buffer means positioned in the pressure vessel above and axially aligned with each of said end fitting means tubular extensions; tubular hydraulic cylinder defining means extending between the upper end of each of said tubular extensions and said buffer means; actuator piston means disposed for movement in each of said tubular cylinder defining means, each of said actuator piston means having an upper surface cooperating with said buffer means for valving action and a lower surface cooperating with said upper end fitting means defined valve seat to perform a valving action; neutron absorber element means disposed for movement in each of the guide tubes; means mechanically coupling each of said actuator piston means to associated absorber element means whereby the absorber element means may be moved relative to the fuel elements; means located externally of the pressure vessel for generating a control pressure; a plurality of control lines penetrating the pressure vessel, said control lines being commensurate in number with the actuator piston means and extending from said control pressure generating means to respective of said control pressure to the upper surfaces of said actuator piston means; valve means disposed in each of said control lines for selectively applying said control pressure to said hydraulic cylinder defining means through said buffer means to said upper surface of said actuator piston means whereby said absorber elements may be individually adjusted between positions commensurate with full insertion into and full retraction from the fuel assembly; and means for applying the pressure vessel internal coolant pressure to the lower surfaces of said actuator piston means.
Claim 2
Dependent Claim
371 words
In a nuclear reactor, the reactor including a pressure vessel with a fuel assembly disposed therein and means for circulating a coolant under pressure through the vessel, the fuel assembly comprising a plurality of fuel elements containing fissionable material, an improved control system comprising: a plurality of guide tubes for movable neutron absorber elements extending through the fuel assembly, said guide tubes terminating within the pressure vessel; upper end filtering means, the upper end of each guide tube being terminated in said upper end fitting means, said upper end fitting means including a tubular extension for each guide tube, the upper end of said tubular extensions defining valve seats; buffer means positioned in the pressure vessel above and axially aligned with each of said end fitting means tubular extensions; tubular hydraulic cylinder defining means extending between the upper end of each of said tubular extensions and said buffer means; actuator piston means disposed for movement in each of said tubular cylinder defining means, each of said actuator piston means having an upper surface cooperating with said buffer means for valving action and a lower surface cooperating with said upper end fitting means defined valve seat to perform a valving action; neutron absorber element means disposed for movement in each of the guide tubes; means mechanically coupling each of said actuator piston means to associated absorber element means whereby the absorber element means may be moved relative to the fuel elements; means located externally of the pressure vessel for generating a control pressure; a plurality of control lines penetrating the pressure vessel, said control lines being commensurate in number with the actuator piston means and extending from said control pressure generating means to respective of said control pressure to the upper surfaces of said actuator piston means; valve means disposed in each of said control lines for selectively applying said control pressure to said hydraulic cylinder defining means through said buffer means to said upper surface of said actuator piston means whereby said absorber elements may be individually adjusted between positions commensurate with full insertion into and full retraction from the fuel assembly; and means for applying the pressure vessel internal coolant pressure to the lower surfaces of said actuator piston means.