Advantages of Chernobyl RBMK reactor

Advantages of Chernobyl RBMK reactor

• As fuel, low enriched Uranium is required (2% 235U), which makes the reactor more economical. By enrichment process, % of 235U content in natural uranium increases from 0.75% to higher content.
  

• Cost of building a RBMK reactor is very less due to no containment building. Containment building is made of a reinforced steel, concrete or lead structure which encloses a nuclear reactor.

• Building reactor is less time consuming also due to the above two reasons.

• As per design, graphite displacers were placed in bottom of the boron carbide absorbers/ control rod. During normal operation of the reactor, graphite portion of the control rod should be inserted into the core, so that coolant natural water (H2O) shall be displaced by graphite. Graphite is a good moderator than natural water. Neutron absorption cross section is less for graphite than water. This allows reactor to remain critical with very less enrichment, e.g. 2%. Light water moderated reactor needs atleast 3% enrichment of 235U. This was a very intelligent way of running a reactor which is light water cooled and low enriched uranium fuel.
  

• Cost of alternative moderator, heavy water (D2O) used for low enriched Uranium reactor like CANDU/ PHWR is also avoided. Graphite is comparatively cheaper alternative.
  

• Fuel sub assemblies can be loaded and unloaded during reactor operation conditions i.e. without shutting down the reactor. This increases the operation time of RBMK reactor. 

  Reference

  Hyperlinked in the text.