GB1282223A - Pulse sequencing system - Google Patents

Abstract

1282223 Control of reactors WESTING- HOUSE ELECTRIC CORP 19 Jan 1970 [13 Feb 1969] 2419/70 Headings G4H and G6C A system for generating electric control pulses to cyclically raise or lower nuclear reactor control rods arranged in banks is adjustable to accommodate different numbers of control rods per bank and/or different numbers of banks while maintaining the pulses for a bank evenly timespaced. A clock 10 drives a counter 30 either forwards or backwards through AND gates 18 or 20. The capacity of the counter is equal to the least common multiple of the factors comprising the factorial of the maximum number of rods ever likely to be in a bank. The counter is decoded to provide pulses on leads P in turn, the number of leads being equal to the above maximum number of rods. In a selector 42 a number of decoder outputs, equal to the number of rods present in a back and evenly time-spread, are multipled to banks of AND gates, each bank being energized in turn by bank control signals (44), so providing sequential control pulses to each bank in turn. Upon start up or a change in direction of the control rod movement, a fast pulse generator 182 is used to obtain the first control pulse of the new sequence, which via OR-gate 186 then inhibits the generator 182 in favour of the slower pulse generator 10. With a change of direction unit 190 inhibits the first control pulse P of the new sequence to ensure that the last rod moved in the previous direction is the first to be moved in the new direction.