Emergency core cooling system for nuclear reactor

In conventional ECCS of a BWR type reactor, since partially cooled water is directly sucked again into after-heat removal system, there is loss of cooling performance. Further, since an internal pump of BWR is disposed between a reactor core shroud and a reactor pressure vessel, this complicates the operation of taking out the internal pump while keeping away from a spurger upon periodical inspection. In view of the above, an injection port for ECCS from an RHR system is disposed to a region at the inside of the reactor core shroud of the pressure vessel. Thus, coolants are injected to ECCS at the inside and the coolants cooled through the heat exchanger in the RHR system are injected above the reactor core thereby enabling to interrupt boiling in the reactor core within ten and several hours after the occurrence of LOCA. That is, since the suction and the injection position in the PHR system can be separated sufficiently cooling efficiency can be improved remarkably. (N.H.)