As the struggle continues to bring the six-year-old triple nuclear
meltdown at Fukushima Daiichi under control, robots are providing a
first, albeit expendable, line of assault.
The robots are on a high-tech suicide mission into the nooks and
crannies beneath the stricken plant’s three melted-down reactor cores to
discover and map an estimated yet elusive 600 tons of molten nuclear
fuel.
Radiation levels in these corridors can reach up to 650 sieverts and
hour, higher by nine times than the previous highs measured at the
plant, which plateaued at a mere 73 sieverts in 2012.
A whole human body dose of 10 sieverts is enough to cause immediate
illness and death within a few weeks at most, 650 within a minute.
Levels like those recently found in the snarls and wreckage beneath
Fukushima’s reactor No 2, where radiation is more concentrated because,
unlike reactor No 1 and 3, it didn’t suffer a hydrogen explosion, are
lethal not just to humans but, as it turns out, to robots as well.
The most recent robot that Tokyo Electric Power Co., the owner of the
Fukushima plant, sent into the breach of reactor No 2 died in less than
a day. The two before that got stuck in narrow passages and were given
up for dead, and a third was abandoned after it spent six days searching
for the reactor’s melted fuel. Yet one more robot was sacrificed in
action while trying to locate one of its lost compatriots.
Data: 09.03.2017
Fonte: www.bellona.org
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