A well-instrumented cooling pond will have at least the following:
| Instrument | Purpose | Key Details |
|---|---|---|
| Installed gamma monitors | Detect loss of shielding | At least 3 instruments required, using 2-out-of-3 voting logic to reduce spurious alarms. Must be positioned so they cannot be shielded from the pond surface. |
| Pond water beta counter | Detect fission product contamination in water | Provides early warning of damaged fuel releasing fission products |
| Air monitor | Detect airborne contamination | Monitors the air above the pond for gaseous/volatile fission products |
Alarm levels for gamma monitors:
| Level | Dose Rate | Action |
|---|---|---|
| Local alarm | ~100 mGy/h | Alert operators; investigate immediately |
| Evacuation alarm | ~100 mSv/h | Evacuate all personnel from the area |