[en] In the multi-loop type nuclear power plant the branching or concentration point of the parallel coolant gas loops is put closer to the reactor core region through which the entire coolant gas flows. For this purpose at least one of the gas plenums is subdivided by means of partition walls in such manner that the gas inlets and outlets of each coolant gas circuit open into a special gas chamber. It has got pressure relief openings with a flow resistance. In the accident case of failure of pressure retaining walls or gas ducts in one of the coolant gas circuits consecutive damages are avoided and the residual heat removal system is kept functioning. A bypass flow of the coolant cannot occur. (DG)