Containment vessel cooling system having the following components: • a sealed containment vessel for a nuclear installation, • a cooling medium-collecting region situated within the containment vessel and serving for receiving a medium to be cooled , • a first heat exchanger situated within the containment vessel and serving for the exchange of heat between the medium to be cooled and a coolant, • first means for extracting the medium to be cooled from the cooling medium-collecting region , supplying said medium to the first heat exchanger for the purpose of cooling, and, after it has flowed through the latter, returning said medium to the cooling medium-collecting region , in a first cooling circuit , wherein the first means have a first pump apparatus , situated within the containment vessel , in order for the medium to be cooled to be made to flow, • second means for supplying the coolant from outside the containment vessel to the first heat exchanger , and, after it has flowed through the latter, returning said coolant to outside the containment vessel , wherein the second means have a second pump apparatus , situated outside the containment vessel , in order for the coolant to be made to flow, • wherein the second means have a turbine which is situated within the containment vessel and which is driven by the flow of the coolant, and • wherein the first pump apparatus is coupled to the turbine so as to be driven by the latter, • wherein the first pump apparatus and the turbine are arranged below the surface of the medium to be cooled , as seen geodetically, during operation, characterized • in that the first pump apparatus and the turbine are arranged outside the cooling medium-collecting region , and • in that the first means comprise a first pipeline which has a first end by way of which the medium to be cooled is able to be extracted from the cooling medium-collecting region and has a second end which is connected to a suction side of the first pump apparatus . • a sealed containment vessel for a nuclear installation, • a cooling medium-collecting region situated within the containment vessel and serving for receiving a medium to be cooled , • a first heat exchanger situated within the containment vessel and serving for the exchange of heat between the medium to be cooled and a coolant, • first means for extracting the medium to be cooled from the cooling medium-collecting region , supplying said medium to the first heat exchanger for the purpose of cooling, and, after it has flowed through the latter, returning said medium to the cooling medium-collecting region , in a first cooling circuit , wherein the first means have a first pump apparatus , situated within the containment vessel , in order for the medium to be cooled to be made to flow, • second means for supplying the coolant from outside the containment vessel to the first heat exchanger , and, after it has flowed through the latter, returning said coolant to outside the containment vessel , wherein the second means have a second pump apparatus , situated outside the containment vessel , in order for the coolant to be made to flow, • wherein the second means have a turbine which is situated within the containment vessel and which is driven by the flow of the coolant, and • wherein the first pump apparatus is coupled to the turbine so as to be driven by the latter, • wherein the first pump apparatus and the turbine are arranged below the surface of the medium to be cooled , as seen geodetically, during operation, characterized • in that the first pump apparatus and the turbine are arranged outside the cooling medium-collecting region , and • in that the first means comprise a first pipeline which has a first end by way of which the medium to be cooled is able to be extracted from the cooling medium-collecting region and has a second end which is connected to a suction side of the first pump apparatus . <EOS>