Deputy director general of the NISA, Hideohiko Nishiyama, also admitted that they do not know if the reactors are coming under control.
He said: ‘With the water-spraying operations, we are fighting a fire we cannot see. That fire is not spreading, but we cannot say yet that it is under control.’
And Yukiya Amano, the head of the U.N.’s International Atomic Energy Agency said workers were in a ‘race against the clock’ to cool the reactor.
Attempts to quell the overheating plant with waterbombs from helicopters yesterday failed and despite the army pelting the site with water cannon, radiation levels rose higher.
Engineers are also working to restore power to the coolant pumping system knocked out by the tsunami.
Also, the Mail shows a dramatic photo of a crane used to move spent fuel rodes into a now empty storage pond.
Pictures emerged showing overheating fuel rods exposed to the elements through a huge hole in the wall of a reactor building at the destroyed Fukushima nuclear plant.
Radiation is streaming into the atmosphere from the used uranium rods at reactor number four, after a 45ft-deep storage pool designed to keep them stable boiled dry in a fire.
And some of the radioactive material could reach Britain within a fortnight, according to experts.
However they say it will not be dangerous when it reaches our shores while low levels of radiation have already hit Southern California.