The operator of the Fukushima nuclear plant in Japan has managed to restore the cooling system in a pool which holds hundreds of tonnes of spent nuclear fuel at the facility.
The system had failed earlier, causing the pool's temperature to rise.
TEPCO says a fault caused the cooling system to shutdown and then a back up system failed to activate.
The pool contains more than 1500 nuclear assemblies, the majority of them containing highly radioactive fuel rods.
There were fears that if the problem was not fixed, the pool could reach its maximum safe temperature of 65 degrees Celsius by Tuesday.
The ABC reports the temperature in the damaged pool touched 43 degrees before the fault was fixed.
TEPCO says it should now gradually fall back to normal.