Hydrogen detonation

Large thermal explosion

Direct containment heating

Overpressure within the containment

Containment failure at later stages due to the basement meltdown

Major positive reactivity insertion (including non-uniform dilution of boric absorber)

Rupture of large-size pressurized components (e.g. the reactor vessel or large-size primary circuit components)

Fuel element failure in the spent fuel storage (pool)

Severe accidents with the containment integrity lost due to its bypass (e.g. in the event of the steam generator tube or header failures, the containment isolation valve failure to close, or an accident with a break in an adjacent system)

Severe accidents in the reactor state when the containment has lost its integrity or the means for eliminating the effects of severe accidents are out of service