Patent Number: 052176789
Section: abstract

A storage 14 of a unit 13 constituting a gang control-rod operating unit stores an A type pattern sequence for configuring an A type control rod pattern, a B type pattern sequence for configuring a B type control rod pattern, and a control rod pattern exchange sequence. The control rod pattern exchange sequence comprises groups subsequent to 5 in the A type sequence and groups subsequent to 5 in the B type sequence. A control panel includes a sequence select switch 12a, a control rod group select switch 12b, and an insert/withdraw select switch 12c. In exchanging the control rod pattern, an operator actuates the sequence select switch 12a to select the control rod pattern exchange sequence, and then actuates the control rod group select switch 12b and the insert/withdraw select switch 12c to operate a plurality of control rods at the same time for carrying out the pattern exchange. The operation of exchanging the control rod pattern is facilitated and reliability is improved. Selection of the control rod pattern exchange sequence is allowed only when reactor power is above a set value at which an RWM 17 is to be released.