They got rid of those and they're using natural circulation to cool the core, again more passive.

他们除去了那些，他们在使用一个自然的再循环，来将核心冷却，还是更被动的。

youdao

The residual heat removal system with natural circulation is a passive safety system.

采用自然循环的余热排出系统是一种被动安全的系统。

youdao

It uses so-called passive systems for cooling, such as the gravity flow of water and natural circulation based on thermodynamics.

WSJ: NRC Approves Toshiba Reactor Design