A Generation IV reactor is a type of nuclear reactor that is being developed to improve upon the Generation III reactors. There are six different types of Generation IV reactors that are being developed: (1) Lead-cooled fast reactors; (2) supercritical water-cooled reactors; (3) gas-cooled fast reactors; (4) molten salt reactors; (5) sodium-cooled fast reactors; (6) helium-cooled reactors. Each type of reactor has its own unique advantages and disadvantages. For example, lead-cooled fast reactors are very efficient but can be difficult to control.
Some of the emerging trends in Generation IV Reactors include the use of molten salt reactors (MSRs), high-temperature gas-cooled reactors (HTGRs), and supercritical water-cooled reactors (SCWRs).