Controllers, water pumps, active protection

Normally where it is necessary, fireproofing is preferred over water spray for several reasons. The fireproofing is a passive inherent safety feature, while the water spray is a vulnerable active system that requires auxiliary control to be activated. Additionally the water spray relies on supplemental support systems that may be vulnerable to failures, i.e., pumps, distribution network, etc. The integrity of fireproofing systems is generally considered superior to explosion incidents compared to water spray piping systems. The typical application of water sprays in place of fireproofing is for vessel protection. 

I - Reactor 2 - Control rod actuators 3 - Primary circuit pump 4 - Metal-and-water shielding tank 5 - Protective shell 6 - SG 7 - Recirculation channels of ECCS 8 - Active channels of ECCS 9 - Barbotage sub-system for emergency pressure suppression in the protective shell 10 - Soluble poison injection system ... 

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