What triggers a stop-work decision in a re-entry operation?

• A. A scheduled shift change.
• B. A crew member’s request for a break.
• C. New or changing hazards, equipment failure, alarms, or unsafe conditions observed by the RCS or entrants.
• D. The weather turning cloudy.

Answer: (C)

In a re-entry operation, stop-work decisions are driven by safety conditions. Work is halted as soon as new or changing hazards are identified, equipment fails, alarms go off, or any unsafe condition is observed by the Re-Entry Control Supervisor or by entrants. This creates a controlled pause to reassess the situation, implement necessary controls, or evacuate if needed, ensuring the crew stays protected.

Administrative items like a scheduled shift change or a crew member requesting a break don’t in themselves indicate a safety hazard, so they don’t trigger stop-work. Weather changing to cloudy isn’t automatically a stop-work trigger unless it introduces or reveals a hazard (for example, reduced visibility or other safety concerns).