GE BWR/4 to BWR/6 and Mark containments

General Electric developed the BWR from Dresden 1 in 1960. The BWR/4, BWR/5 and BWR/6 generations of the 1970s and 80s make up most of the BWRs in operation. They pair with three containment types: the Mark I, with its light-bulb-shaped drywell and suppression torus, the conical Mark II and the Mark III, closer to a PWR's.

Fukushima Daiichi 1 to 5 were BWR/3 and BWR/4 units with Mark I containments. After 2011, filtered vents and spent fuel pool cooling were reinforced across the fleet. The United States operates about 30 GE BWRs; Japan, Mexico, Spain, Switzerland and Taiwan have or had units of this family.