01 How It Works
The RBMK uses graphite as a moderator and boiling water as coolant in separate pressurised channels running through the graphite core. This design allowed refuelling while operating - useful for plutonium production. However, the graphite moderator continued slowing neutrons even if cooling water boiled away, meaning the reactor could become MORE reactive as power increased - a "positive void coefficient" that made it inherently unstable at low power.
02 Pros & Cons
โ Advantages
- Can be refuelled while operating (no shutdown needed)
- Uses natural or slightly enriched uranium
- Large power output from modular channel design
- Built from standard industrial materials
โ Disadvantages
- Positive void coefficient - dangerously unstable at low power
- No proper containment building in original design
- Graphite fire risk if core exposed
- The AZ-5 "emergency shutdown" button triggered Chernobyl
03 Specifications
THERMAL EFFICIENCY~25%
OPERATING TEMP~284ยฐC
PRESSURE~6.5 MPa (channels)
FUELLow-enriched UOโ (2%)
FUELLow-enriched UOโ (2%)
COUNTRIESRussia (remaining), Ukraine (closed), Lithuania (closed)
04 Did You Know?
The RBMK's fatal flaw: at low power, the reactor became MORE reactive if coolant boiled away. Soviet operators were not told this. Chernobyl Unit 4 was at 7% power when it exploded.