There are only 35 days or less until the fuel sustains a full-scale fission criticality. The boron, (which stops nuclear fission from occurring) will have exceeded its lifespan by this time…
Tepco had already made a request as of march to evacuate the reactors

Tepco will likely evacuate the site between the dates: June 16th – June 28th…“This is because boron is limited and can no longer sustain its self within the current settings”.