Backlash from the reactor is likely to be an even bigger problem when the water inside the reactor is much more radioactive than usual and is under extremely high pressure.

In a pressurised-water reactor, hot water circulates at high pressure through steel piping, dissolving metal ions from the walls of the pipes.

As the basic safe wall of nuclear reactor, the reactor pressure vessel not only bears high temperature and high pressure, but also contains radioactive working substance.