Thanks for the info about sheeting. When it was first proposed the obvious concerns were heat - it’s too hot to put concrete on it so let’s put polyester instead.
You know, I wouldn’t be as skeptical as I am if a) putting polyester over 3 core melt downs had ever been tried before and b) TEPCO wasn’t the one proposing it. After all their evasion and lying and their request to abandon all attempts to contain the reactors in mid March, I believe TEPCO has earned the snarks it gets.
The polyester lining is aimed at avoiding rain water to rinse the debris on top of the three units, therefore increasing the aumount of radiactive water to be processed.
Typhoon session there coming soon.