 After an initial agreement between Ronald Reagan and Mikhail Gorbachev in November 1985, the International Thermonuclear Experimental Reactor (ITER) effort emerged and remains the primary international effort to develop practical fusion power.Many smaller designs, and offshoots like the spherical tokamak, continue to be used to investigate performance parameters and other issues., JET remains the record holder for fusion output, reaching 16 MW of output for 24 MW of input heating power.