Via The Daily Yomiuri: N-plant has long road ahead / Experts: Decommissioning Fukushima reactors to take decades. Excerpt:
Nuclear experts predict it will take decades to complete the decommissioning of the Nos. 1 to 4 reactors at the Fukushima No. 1 nuclear power plant.
Tokyo Electric Power Co. Chairman Tsunehisa Katsumata said Wednesday the company will decommission the four reactors, but the most pressing task at the moment is how to dispose of the huge quantity of water that has become contaminated with radioactive materials after being used to cool the reactors. Just disposing of this water will take a long time.
An estimated 13,000 tons of contaminated water has accumulated in trenches--tunnels used for maintenance of the reactors. A large quantity of contaminated water also has to be extracted from the basements of the reactors' turbine buildings, although the exact amount is unknown.
If the contaminated water can be removed, it will pave the way to reactivating the reactors' original cooling systems, which can lower the temperature of the reactor cores more efficiently than the methods now being employed.
Currently, however, workers at the plant are stymied by the contaminated water. They cannot even connect power cables outside the plant to the reactors' control systems.
It may be impossible to restore power to the reactor control systems if internal radiation levels are so high workers cannot repair the machinery, or if the contaminated water cannot be removed.
If water continues to leak, external tanks for temporarily storing it may become full. Workers and experts have said new facilities to store the contaminated water must be secured as soon as possible.
If all the contaminated water can be removed, the reactors then must be put in what is called cold shutdown to prevent the further discharge of large quantities of radioactive substances and bring the reactors into a stable state.
Cold shutdown means all control rods have been inserted into the reactors to stop nuclear fission chain reactions, and the coolant water inside the reactors is below 100 C.
Usually the temperature needs to be lowered further to remove fuel rods for regular checks or decommissioning.
"If the original cooling systems can be activated through a power supply from outside the plant and coolant water circulated, cold shutdown can be achieved in a day or two," Prof. Kenichiro Sugiyama of Hokkaido University said.
But it will likely take a few more years for the nuclear fuel rods to be cool enough to be removed from the reactors to decommission them.
Over half a century ago, I read a novel by Lester Del Rey called Nerves. Published in 1956, it described an accident at a nuclear plant. We knew about this possibility right from the start.
He said it sounded "bleak," but he bought it. The novel I finally sent him wasn't much like the original outline, but he bought that, too—and said he couldn't find anything to revise. I took that as very high praise indeed.
We SF writers are notorious for our lack of imagination, but some of us, like Lester Del Rey, can see what's coming. Ray Bradbury (who is still alive, bless him!) said, before you were born, that the job of science fiction is not to predict the future, but to prevent it. If we SF writers fail in that task, it's not our fault. God knows we saw it coming.
