[sefarkas]

Within the containment building, the reactor coolant system and reactor vessel (where the fuel is) is surrounded by dense and (in places) several feet thick rebarred concrete. Note that the containment building (shield) wall is also two to three feet thick rebarred concrete. I am unfamiliar with the KWU containment, but the wall of American containment buildings are lined with thick leak-proof steel. Other designs have a free-standing steel building inside the containment walls. Even if a weapon penetrated the two barriers (shield wall / gas-containment-steel), the explosion would largely stay within the containment. Again, it would be more effective to destroy the steam turbine in the adjacent building. It takes years to order, build and deliver a steam turbine big enough to generate over 900MWe.

[tacticalogic]

If the objective is to destroy the reactor and prevent it from being used to produce material for nuclear or "dirty" weapons with minimal collateral damage, then you'd want all the damage to be within the containment.

The idea was to use a penetrator to punch a (repairable) hole in the containment dome and rupture the reactor vessel so that everything inside the dome is unsalvagable, including the fissibles.