- Another Japanese nuke will soon be shut down. Sendai #2, a ~900 Mwe Pressurized Water Reactor plant will be shut down for periodic maintenance and inspection next week. The plant operators will begin reducing power output on Wednesday, and have the unit completely off the grid by Thursday. Although this will make no difference to the politicians starving Japan’s power grid in the interest of gaining votes, we thought everyone should know…The Sendai containments are a virtual light year in difference from the ones at Fukushima. Unlike the “light bulb” design of the Fukushima containment vessels, Sendai uses the much bigger, stronger GE Mark III structure, similar to the one at Three Mile Island. Remember, TMI’s containment had what is thought to be a hydrogen explosion inside it, and remained robust and undamaged. If unit 1, 2 & 3 at Fukushima has Mark IIIs around them, it is possible that the three demolished buildings and large radioactive releases would have been avoided.This will place more than 80% of Japan’s nuclear capacity in an idled condition. Let’s make a prediction…when idled nukes pass the “stress test”, will they be allowed to restart? Probably not. It’s not a question of if the plants are safe enough. It’s politics. What the politicos feel will garner the most votes will drive their decisions. Meanwhile, Japan’s energy infrastructure continues to weaken. Yomiuri Shimbun says that power usage has dropped 20% since the government invoked mandatory industrial cutbacks of 15% and asked residential customers to voluntarily reduce consumption. However, as more and more nukes are idled, even these power consumption reductions will not be enough. Winter peak demand will still be as much as 10% above what existing supplies can produce. In addition, many outdated, “mothballed” fossil fueled units have been restarted to compensate for the political moratorium on nukes, and they are dirty, inefficient, and unreliable.
- TEPCO has announced a plan for de-fueling Fukushima Daiichi units 1, 2 & 3 RPVs. If they are correct and all three fuel cells have severely melted, with some fuel having leaked out of one or more of the RPVs, this will be an entirely new process to the world. Stage one will remove all radioactive debris from inside and outside the three reactor buildings. This will reduce the radiation fields somewhat, extending the amount of time workers can stay in the buildings (stay times). Stage two will begin with entries into the Primary Containments (PCV) surrounding the RPVs to find leaks and seal them up. Then, they will begin increasing the water levels the RPVs and PCVs to make sure all leaks have been sealed and no more waste waters will leak into the basements of the attached structures. Most of stage one and two will have to be done remotely using robots because the radiation levels are so high that workers would not be able to do the job because of very short “stay times”. The third stage will be to completely fill the RPVs and PCVs with water, which will provide two important benefits. (1) Water is a very effective radiation shield and will reduce the exposure fields immensely, increasing human “stay times” dramatically. (2) The tops of the RPVs (Vessel Heads) will be removed under water and the extent of actual damage inside the RPVs will be known for the first time. Then, planning for removal of the solidified corium can begin, and not before (with any degree of confidence). This will differ considerably with the de-fueling of Three Mile Island in the 1980s, and in no way comparable with Chernobyl (which might never be de-fueled).Of course, critics in Japan are immediately finding fault with TEPCO’s plan, which should surprise no one. Many international anti-nuke groups say the plan is overly-ambitious and too dangerous to be allowed. They want all three RPVs entombed like Chernobyl for. It would make their “Fukushima is another Chernobyl” propaganda seem realistic. Is the TEPCO plan ambitious? Yes! Unrealistic? No!
- An Asahi Shimbun article contains the following important statement, “A survey of residents near the quake-stricken Fukushima No. 1 nuclear power plant indicated that the level of lifetime internal exposure for them is estimated at less than 1 millisievert.”
- The Japanese government has released detailed radiation exposure maps of the 20km no-go zone and the evacuated corridor 32 km. to the northwest. Unfortunately, its only in Japanese and Google translate won’t work on it. (firewalls?) Anyway, NHK World summarizes some of the extremes. The highest reading is Okuma Town, which is located between 1 and 2 km southwest of the plant, with an exposure level of 139 microsieverts/hr (~1000 msv/yr). The lowest, at only 1 microsievert/hr (9 msv/yr), are the coastal areas 3km north of the power complex. 9 msv/yr has never hurt anyone and is well below the statistically safe 50 msv/yr natural background levels found around the world, which we advocate as a rational health standard. Some readings in the northwest evacuation corridor were around 19 millisieverts/hr (~100 msv/yr), but inside most of the mapped area we posted Wednesday the readings are well below 50 msv/yr. In other words, if natural background levels were being used rather than the arbitrary risk models now in effect, many of the Fukushima evacuees could go home and no-one would be at harmed.
- Most Japanese news services have headlined that two Fukushima workers “showered with radioactive water”. Misleading, to say the least. It turns out the two men were near a “container” which had a mistakenly-open valve on its piping. Water sprayed from the pipe and the men were covered by the spray. One was wearing rain gear, so he was minimally exposed (~1.4 msv). The second man was wearing standard anti-contamination cover-alls, which are not waterproof, so he received ~14 msv exposure. No exposure limits were exceeded and neither man was injured in any way.TEPCO’s use of the term “showered” is unfortunate, at best. It makes it seem the men were bathing in contaminated water, which is entirely not what happened. When will TEPCO wake up and anticipate the worst possible “spins” by the world’s Press? Their terminological naivety is massive.
- The Mainichi Shimbun reports TEPCO will build a large underground barrier around the Fukushima unit #1 to prevent contamination of area groundwater by waste waters in the plant buildings. Only one problem with this…groundwater flow is from land to sea, not the reverse direction. Later in the Mainichi article, we find out it will be a barrier between the unit #1 buildings and the sea, and has nothing to do with groundwater protection. Now, that makes sense. It’s protecting the sea. Regardless, The Mainichi contradicts its headline within the very same article. Combined with it’s “penetrating” Beta radiation error two days ago, The Mainichi has exhibited some serious reporting failures this week.
- In case anyone has forgotten, the clean-up of the mountains of earthquake and tsunami rubble and debris continues. NHK World reports that nearly all the several million tons of debris from the Fukushima coast (except for the 20km no-go zone), and the two adjacent Prefectures of Miyagi and Iwate, has been removed and disposed of. However, the other nine Prefectures which were also hit by the tsunami still have more than half of their debris to remove…roughly 12 million of the original 23 million tons. Local officials say that at this rate, it will be next March before the mess will be finally cleaned up. It seems the Fukushima accident region has received the most intensive clean-up focus, at the expense of the other nine Prefectures.What’s wrong with this picture?