Pockets of lethal levels of radiation have been detected at Japan's crippled Fukushima Daiichi nuclear plant in a fresh reminder of the risks faced by workers battling to contain the worst nuclear accident since Chernobyl.
Plant operator Tokyo Electric Power (Tepco) reported on Monday that radiation exceeding 10 sieverts (10,000 millisieverts) per hour was found at the bottom of a ventilation stack standing between two reactors.
On Tuesday Tepco said it found another spot on the ventilation stack itself where radiation exceeded 10 sieverts per hour, a level that could lead to incapacitation or death after just several seconds of exposure.
The company used equipment to measure radiation from a distance and was unable to ascertain the exact level because the device's maximum reading is 10 sieverts.
While Tepco said the readings would not hinder its goal of stabilising the Fukushima reactors by January, experts warned that worker safety could be at risk if the operator prioritised hitting the deadline over radiation risks