I simply DO NOT BELIEVE IT.
How can you turn off the reactor and cooling without a disaster?
Approximately 10% of the heat generated by a nuclear reactor comes from radioactivity of fission products. This "afterheat" can NOT be turned off by any means whatsoever. That means that the reactor will still be producing some 10% of its normal operating heat for hours, even days. That is why reactors must be cooled down for weeks before being refueled.
This is more than enough heat energy to boil the remaining coolant, burst containment, melt or ignite the reactor core, etc. The heat MUST be removed and taken to a heat exchanger outside the reactor proper.