Suspended nuclear reactor containments with reduced thermal stress

Claim 1

A containment for a nuclear reactor comprising: a pre-stressed concrete structure, defining a cavity having a substantially hemispherical base and a horizontal plane roof, a steel membrane lining for the cavity, a primary vessel for containing a nuclear reactor core and ancillary equipment generally submerged in liquid coolant, the primary vessel being suspended by attachment at its rim to the roof lining and to steel anchors in the roof structure concrete, an annular tank for containing liquid metal in contact with the external surface of the upper peripheral region of the primary vessel and having cooling coils for passing a first coolant fluid through the tank in heat exchange with the liquid metal, thermal insulation of varying thickness disposed about the primary vessel below the annular tank, the thermal insulation reducing in thickness towards the rim of the primary vessel, and a jacket embracing the thermal insulation, the jacket having inlet and outlet connections for a second coolant fluid.