I hoppe you will excuse me to have done it in spite of my very low knowedge in the nuclear field.
Although it's better to try to have one evaluation than nothing , my problem is the way our specialists are reckoning the risks we incur. Is it temerity to pretend to give a risk evaluation?
Amung the risks I have heard on the net about nuclear safety, I have found :
Destruction of power supply.
Lack of water for some plant nears rivers (because of tectonic faults).
Destruction of the building around the reactor because of plane-crash or bombing
Destruction of water pipes in charge of cooling for the same reasons.
Lack of air in case of air colling.(why not).
Destruction of all electrical installations.
Destruction of the staff in charge of the plant.
Finally, in spite of the backups, we might have have to face the loss of every thing but the reactor itself and its containement:
No cooling, no staff, no electricity, no backup, nothing.
In this case, we might want a solution that would work automatically.
That's why I thought in my posting after Fukushima about a solution using gravity to expel the fuels rodes from the core. To isolate and to cool them. To stop the nuclear reaction to it's minimum. To return to the state they were berfore entering the core. Perhaps it would be easier in this new location. If there is a container at the end of the tube then it might be possible to separate it from the core and to continue to cool it somewere else. The best solution being: to let them cool alone without having to act. How could we release automatically the fuel rod? Perhaps using an ergot that melt automatically before the rod itself melt. The melted ergot will let the fuel-rod fall.
What if the core start to melt? Using tubes at the bottom of the core. Eject the melt with the help of gravity. But what could we use at the end of these tubes to recieve spread and cool automatically the melt? Sand?
Perhaps such solutions are allready used in the new nuclear plants. Perhaps they are dangerous solutions or simply not possible. Do they? We have the right to know more precisely. Particularly I'd like to know what will happen if nothing is left to manage, scrutinize and cool the reactor.
I hope again that you will excuse me for pretending to find simple solutions when courageous people are being intoxicated, risking their life and health to restore a normal situation at Fukushima nuclear plant.