RBMK
Reaktor Bolshoy Moshchnosti Kanalnyy
RBMK is a Soviet graphite-moderated, light-water-cooled reactor with individual fuel channels, known for Chernobyl design flaws.
1000 MWe units use 2% enriched uranium in 18cm channels, with graphite stack moderator enabling positive void coefficient at low burnup. Eleven RBMK-1000s built in USSR; post-1986 modifications added fast-acting control rods. Operations limited to Russia with phase-out planned.
Why it matters now
Remaining RBMK units in Russia face extended licenses into 2026 but highlight risks, contrasting with safer Gen III+ designs in current SMR licensing wave.