ANLAGE MIT EINEM NUKLEAREN REAKTOR, INSBESONDERE HEIZREAKTOR

PCT No. PCT/CH88/00009 Sec. 371 Date Sep. 6, 1988 Sec. 102(e) Date Sep. 6, 1988 PCT Filed Jan. 14, 1988 PCT Pub. No. W088/05595 PCT Pub. Date Jul. 28, 1988.The reactor core of the plant has tubular vertically movable control rods moved by a pressurized flowing coolant. Each control rod so extends around a tubular guide rod which is immobile relatively to the reactor core as to leave a first annular gap between the control rod and the guide rod. The guide rod interior is operative as a first pressure chamber to which the pressurized coolant is supplied. The top end of each control rod is closed and has a vertical spindle which extends into the guide rod interior and co-operates with the guide rod to bound a second annular gap. At least one first restrictor is disposed in the first annular gap and at least one second restrictor is provided in the second annular gap. A second pressure chamber is present between the two restrictors. The coolant inflowing to the guide rod therefore returns by way of the second annular gap, the second pressure chamber and the first annular chamber to the pressure vessel which extends around the reactor core. Control means are provided to enable pressure surges to be produced as required in the coolant in the first pressure chamber.