The dilemma over the ever-growing radioactive
water is part of the complex aftermath of the
magnitude 9.0 earthquake and tsunami that
hit on March 11, 2011, destroying key cooling
functions at the Fukushima Dai-ichi plant. Three
reactors melted, releasing massive amounts
of radiation and forcing 160,000 residents to
evacuate. About 40,000 still haven’t returned.
Except for the highly radioactive buildings that
house the melted reactors, most above-ground
areas of the plant can now be visited while
wearing just a surgical mask, cotton gloves,
a helmet and a personal dosimeter. The area
right outside the plant is largely untouched and
radiation levels are often higher.
The underground areas remain a hazardous
mess. Radioactive cooling water is leaking
from the melted reactors and mixes with
groundwater, which must be pumped up
to keep it from flowing into the sea and
elsewhere. Separately, even more dangerously
contaminated water sits in underground areas
and leaks continuously into groundwater
outside the plant, experts say.
The contaminated water pumped from
underground first goes through cesium and
strontium removal equipment, after which
most is recycled as cooling water for the
damaged reactors. The rest is filtered by the
main treatment system, known as ALPS,
which is designed to remove all 62 radioactive
contaminants except for tritium, TEPCO says.
Tritium cannot be removed from water and
is virtually harmless when consumed in small
amounts, according to Japan’s industry ministry
and nuclear regulatory officials.