Generation IV reactors? Generation V reactors?

Generation IV reactors are a set of nuclear reactor designs currently being researched for commercial applications, with depending on the particular design,Technology readiness levels varying between the level requiring a demonstration, to economical competitive implementation.
Most of these designs, with the exception of the BN-1200 reactor, are generally not expected to be available for commercial construction before 2030-40.


Presently the majority of reactors in operation around the world are considered second generation reactor systems, as the vast majority of thefirst-generation systems were retired some time ago, and there are only a dozen or so Generation III reactors in operation .
.Generation V reactors refer to reactors that are purely theoretical and are therefore not yet considered feasible in the short term, resulting in limited R&D funding.