Almost three years after the accidents, TEPCO is about to begin the dangerous and arduous task of removing spent fuel rods from the storage pool at Unit #4. This reactor was not running when the earthquake/tsunami hit, but hydrogen explosions severely damaged the spent fuel pool and its surrounding buildings. This is just one of the areas where water has had to be continually pumped in to keep the rods cool and shielded, yielding massive amounts of contaminated water to be dealt with.
The plan is to use a makeshift crane to individually lift the 1500+ fuel assemblies and place them in a heavily shielded cask. All this needs to happen underwater, and in a heavily damaged building. The cask, which can hold about 20 assemblies, will be sealed, and then transported “somewhere” away from the nuclear site where the process will be reversed. The cask will be placed underwater in a new pool, and the fuel assemblies will be removed and re-racked in the new storage area. The cask will be returned to Unit #$ and the process will begin again. This is expected to take about two years to complete.
Why TEPCO is not putting the fuel assemblies directly into dry casks for storage is anybody’s guess. That technology appears to be a US initiative, and Japan probably does not have the technical resources to do it. Here at Humboldt Bay, we built a storage bunker for six casks. The spent fuel was loaded directly into the casks (underwater), and then transported a few hundred yards to the bunker. The advantage of this process is that the fuel does not have to be water-cooled, so you do not have “leakage” problems. And once a repository is available, you don’t have to re-load the fuel into new transportation casks. Fukushima will be handling that fuel at least three times in its long life.
I would imagine that cost has a lot to do with this decision. Here in the US, the casks cost about $2 million each, and all the associated loading and handling brings that total to about $10 million each. Fukushima would need about 30 casks…total project cost could be $300 million. Their thinking might be that it is probably cheaper to “kick the can down the road” and put this stuff in a swimming pool, maintain it and hope it doesn’t leak, and let future generations deal with all this later. After the fuel is removed, Unit #4 can be decommissioned. Since the reactor was not damaged, the decommissioning costs would probably be around $1-2-? billion.
This is the least of TEPCO’s problems. Units #1,2, & 3 have melted fuel inside their reactors, as well as spent fuel assemblies in their spent fuel pools. How all this will be handled is anyone’s guess…as one engineer said “the full decommissioning of Fukushima is likely to take many, many decades and include tasks that have never been attempted anywhere in the world.”
TEPCO estimates the full decommissioning to cost about $50 billion. I would venture to say that this could actually run into $100-200 billion…many times more that the capital value of Japan’s entire nuclear program, and take 60 years to complete…if ever. Add to that the other economic costs…social, environmental, etc., and we might begin to understand the significance of this “accident.” With Chernobyl, nobody really knew/knows the full extent, although there have been many guesses and assumptions. This was in a rather isolated part of the Russia, and the powers that be kept a pretty good lid on it. With Japan, a small island with important standing in the modern world, and with the contamination of the Pacific Ocean and all which that signifies, the world is well aware of what is going on, and hopefully will learn its lessons. This can happen anytime, and anywhere there is a nuclear power plant. Again, I question the economics of nuclear power.