What is the safety injection system and what is its function during accidents?

What is the safety injection system and what is its function during accidents?

• A. The safety injection system injects coolant into the steam generator to maintain pressure.
• B. The safety injection system injects neutron-absorbing fluids into the reactor core to rapidly reduce reactivity and control temperatures.
• C. The safety injection system vents steam to reduce pressure.
• D. The safety injection system trims the reactor power by adjusting control rods.

Answer: (B)

During accidents, the safety injection system is part of the emergency core cooling approach. Its main job is to inject neutron-absorbing fluids, typically borated water, into the reactor core. This rapidly reduces the fission reaction rate (because the boron absorbs neutrons) and provides effective cooling to the fuel, helping prevent overheating and potential fuel damage. This dual action—lowering reactivity and supplying coolant—is what makes it the critical safety response in such scenarios. The other options describe different functions: injecting into the steam generator to keep pressure, venting steam to relieve pressure, or trimming power with control rods—each of these serves a separate system or purpose, not the emergency neutron-absorbing injection into the core.

During accidents, the safety injection system is part of the emergency core cooling approach. Its main job is to inject neutron-absorbing fluids, typically borated water, into the reactor core. This rapidly reduces the fission reaction rate (because the boron absorbs neutrons) and provides effective cooling to the fuel, helping prevent overheating and potential fuel damage. This dual action—lowering reactivity and supplying coolant—is what makes it the critical safety response in such scenarios. The other options describe different functions: injecting into the steam generator to keep pressure, venting steam to relieve pressure, or trimming power with control rods—each of these serves a separate system or purpose, not the emergency neutron-absorbing injection into the core.