Overview
A SCRAM is an emergency shutdown action intended to rapidly place the reactor in a safe state.
⚠️ Emergency procedure
If reactor conditions become unsafe, immediate shutdown action may be required.
When a SCRAM may be necessary
Examples include:
- Severe reactor instability
- Critical cooling failure
- Uncontrolled rise in power
- Major safety system fault
- Conditions outside safe operating limits
Immediate actions
1. Initiate shutdown
Activate the SCRAM or emergency shutdown system in accordance with plant procedure.
2. Confirm system response
Check for evidence that shutdown actions have taken effect, such as:
- Falling reactor output
- Correct rod movement
- Appropriate alarm response
3. Monitor post-shutdown conditions
Continue observing:
- Core temperature
- Coolant flow
- Water level
- Pressure behaviour
- Safety system status
4. Do not restart immediately
A SCRAM should always be followed by system review and fault assessment before any attempt to return to service.
After-action priorities
- Identify the cause
- Confirm plant stability
- Record abnormal indications
- Review operator actions
- Follow post-trip procedure