Fukushima Nuclear Clean-Up
After many long months of repair work and planning, Japan is now entering the most critical stage of clean up after the worst nuclear accident in all of history. Engineers have spent month’s carefully removing rubble and debris from inside the #4 reactor pool and reinforcing its structure. They are now prepared to begin moving 400 tons of radioactive fuel out of the crippled reactor and into safe storage, the first of many steps on the long road to clean up.
Engineers have now extracted 2 of 1500 spent nuclear fuel rods from a storage pool in Unit 4. That is just in the #4 reactor, there still are units 1, 2 and 3 to deal with but Reactor 4 must be addressed first as it has the most significant problems structurally - the building is collapsing and is precariously near sinking into the ocean. Molten fuel from three neighboring reactors that suffered meltdown won't begin until 2020. The entire decommissioning process of all four units is expected to last at least three decades.
The rod assemblies will be lifted out in batches of 22 and in casks filled with water. The fuel rods will then be deposited into a new onsite "common" pool with a built in cooling system.
The fuel rods must be kept underwater at all times - contact with the air would trigger an above-ground chain reaction meltdown releasing radioactive fallout with no way to stop it.
Many factors make this a monumentally perilous operation:
The fuel pool contains damaged rods and racks. The zirconium cladding which encased the rods burned when water levels dropped, to what extent the rods have been damaged is not known, and probably won't be until removal is attempted.
Saltwater cooling has caused corrosion of the pool walls, fuel rods and racks.
Computer-guided removal will not be possible; everything will have to be done manually.
The process of removing each rod will have to be repeated over 1,300 times without incident.
If the rods should touch or even come into close proximity to one another, they would set off a nuclear chain reaction that cannot be stopped.
TEPCO cannot attempt this process without humans, which will manage this enormous task while being bombarded with radiation during the extraction. This is one of the worst, but most important jobs anyone has ever had to do. The 6000 workers carrying out this task are true heroes.
If the operation goes as planned, attention will then focus on the massive challenges posed by Units 1, 2 and 3. Radiation levels in those reactors are still too high for humans to enter, and attempts to use robots to determine the exact location of the melted fuel have so far failed.
Readings in units 1 and 2 show the presence of water in what's called the primary containment vessel - suggesting that the melted rods have not penetrated the safety barrier. But the radiation levels are too high in Unit 3 to conduct a thorough analysis in order to make that determination.
The only good news to come out of this is that the mechanisms and systems put in place to move the spent rods in fairly commonplace and the process is routine for the thousands of nuclear sites that proliferate our planet, the bad news is TEPCO has never done it on a damaged facility before.
More bad news is that spent fuel pools were never intended for long-term storage, they were only to assist short-term movement of fuel. Using them as a long-term storage pool is a huge mistake that has become an “acceptable” practice and is repeated at reactor sites worldwide.
It would be reassuring if experts from other nations were allowed to inspect the site, make recommendations and observe the process. Or better yet, do the work in light of TEPCO’s abysmal record to date in managing the cleanup.
Meanwhile, the world continues to be plagued by tons of radioactive water flowing into the Pacific Ocean that will be ongoing for not only our lifetimes, but our children’s' lifetimes. We have increasing contamination of the food chain, through bioaccumulation and biomagnification. Also a newly stated concern is the proximity of three 100-ton melted fuel blobs underground in relation to the Tokyo aquifer that extends under the plant. Whatever 'barriers' TEPCO has put in place so far have failed. Efforts to decontaminate radioactive water have failed. Robots have failed. Camera equipment and temperature gauges...failed. Decontamination of surrounding cities has failed.
The nuclear industry needs to come clean. If this leads to every reactor in the world being shut down, so be it. If the world governments truly care about their people and this planet, this is what needs to be done.