opens at top dead centre and closes at bottom dead centre

opens at 20 Degree before top dead centre and closes at 40 Degree after bottom dead centre

opens at 20 Degree after top dead centre and closes at 20 Degree before bottom dead centre

none of these

pressurized water

boiling water

gas cooled

liquid metal cooled

Yes

No

Unknown

None

U₂₃₃ and Pu₂₃₉

U₂₃₅ and Th₂₃₂

U₂₃₅ and Pu₂₃₈

U₂₃₃ and Pu₂₃₈

half

same

double

four times