Nuclear reactor automatic safety mechanism - incorporates pipe within core contg. detection fuel rods and controller liberating neutron-absorbing bundle at critical coolant temps.

摘要

An automatic safety mechanism, which casues a neutron absorbing poison to fall rapidly into the core of a nuclear reactor when the temo. of the cooling fluid reaches a critical value, incorporates a safety pipe placed in the core and extending above it, a vertical flow of reactor cooling fluid through the pipe, and a poison bundle which absorbs neutrons. The bundle is held by a support and is movable within the pipe. A number of fuel rods are placed axially in the path of the flow of cooling fluid. A controller sensitive to temp. is situated in the flow near the upper end of the fueld rods. A holder is mounted between the support and the controller so as to suspend the poison bundle above the core and to free it when the controller operates. The invention overcomes the disadvantages of existing mechanisms, which include slowness of operation, difference between the operating temp. and the mean temp. of the cooling fluid at the outlet, and inability to return to position after a stoppage. The mechanism is rapid, reliable and can be easily tested.