A reactor scram test validates which capability, and when is it typically performed?

A reactor scram test validates which capability, and when is it typically performed?

• A. Verifies gradual withdrawal of control rods during steady operation.
• B. Verifies rapid insertion of control rods when commanded, performed during commissioning, major refueling outages, or after maintenance.
• C. Checks heat exchanger effectiveness during normal operation.
• D. Tests emergency diesel generator lockout.

Answer: (B)

Rapid reactor shutdown through prompt control-rod insertion is what’s being tested. A reactor scram test verifies that when a scram command is issued, the control rods move quickly into the core to halt fission and bring the reactor to a safe shutdown. This test is typically performed during commissioning, major refueling outages, or after maintenance to confirm the safety system will respond promptly under real conditions. It also checks that the rods insert fully and that reactor instrumentation and interlocks correctly reflect insertion and reduction of power. The other options describe activities not related to a rapid shutdown capability: gradual withdrawal during steady operation relates to normal reactivity control, heat exchanger tests relate to heat transfer performance, and diesel generator lockout relates to another safety system.

Rapid reactor shutdown through prompt control-rod insertion is what’s being tested. A reactor scram test verifies that when a scram command is issued, the control rods move quickly into the core to halt fission and bring the reactor to a safe shutdown. This test is typically performed during commissioning, major refueling outages, or after maintenance to confirm the safety system will respond promptly under real conditions. It also checks that the rods insert fully and that reactor instrumentation and interlocks correctly reflect insertion and reduction of power. The other options describe activities not related to a rapid shutdown capability: gradual withdrawal during steady operation relates to normal reactivity control, heat exchanger tests relate to heat transfer performance, and diesel generator lockout relates to another safety system.