RBMK

The RBMK is an early Generation II reactor and the oldest commercial reactor design still in wide operation. Certain aspects of the RBMK reactor design – namely the graphite-tipped control rods, the positive void coefficient characteristic and instability at low power levels – contributed to the 1986 Chernobyl disaster in which an RBMK explode...
Found on http://en.wikipedia.org/wiki/RBMK

RBMK

Russian reactor design which uses a graphite moderator and natural water coolant.
Found on http://www.encyclo.co.uk/local/20841
No exact match found