Massachusetts Institute of Technology has posted a report suggesting possible nuclear safety improvements out of the lessons learned from Fukushima. Unlike the recent NRC recommendations for safety improvements, all of MIT’s suggestions are specific to what happened at Fukushima. Interestingly, many of MIT’s conclusions serve to validate what we have been saying for months. Keep in mind the MIT report is a listing of suggestions for safety improvements. This is because, “Not all the information needed for a detailed reconstruction and analysis of the accident is yet available. The need for and merit of the corrective actions described in this document should be re-assessed as more accurate and complete information about the accident becomes available.” Here’s the link…
There are two important “suggestions” we feel carry the most merit. First, “overly-conservative” evacuation zones of greater than 20 miles (~30 kilometers) should not be implemented when the accident is caused by a severe, over-riding natural disaster. Overly-conservative precautions serve to divert resources away from the immediate natural disaster emergency efforts and unduly amplify the fear already inflicted on the surrounding population by the natural catastrophe. From our perspective, it seems the Japanese government has been more concerned about management of hypothetical nuclear risk than they are about recovering from the devastating effects of the earthquake and tsunami.
Second, the methods used to transmit radioactive contamination and whole-body exposure levels are not well-understood by the public-at-large and tend to be counter-intuitive. A more intuitive, easier-to-grasp method of relaying radioactivity information needs to be implemented. MIT suggests using the average international natural background level of 2.4 msv/year (0.27 micro-sieverts/hour) as a foundation, and then report accident-related levels relative to background. At first, the change will be challenged by critics, but over time it should provide the public with a more objective basis for judging whether or not an exposure level is safe. Saying a radiation level is “10 times background” is much easier to understand than stating an exposure level is 2400 micro-sv/yr. What does the term “sievert” mean to the general public? In addition, the public need not be versed in numerical prefixes (e.g. milli vs. micro). The concept that “natural and normal is safe” will tend to drive public opinion, rather than no-safe-level misconceptions, because a background referent does not imply a magnitude of risk. We agree with MIT in essence, but would rather the defining, predicating background level more reflect the higher annual exposures in the world that have not hurt anyone. Not the single highest level (Ramsar, Iran = 250 msv/yr), but perhaps the more common 50 msv/yr (5.6 microsieverts/hr) found with Brazil beaches, the Kerala Region of India, and etc.
Another MIT suggestion concerns using a ceramic, such as Silicon-Carbide, instead of Zirconium as the cladding material in the fuel cells. While a ceramic might be less transparent to neutrons than Zirconium, it would not produce hydrogen if severely over-heated. Sounds like a good idea, doesn’t it?
Finally, MIT suggests that regulatory changes not be made as a result of over-reactive and emotionally-based response to Fukushima. We wholly agree. The real human disaster in Japan is the earthquake and tsunami, whereas the risks from Fukushima are hypothetical. Regulatory changes due to Fukushima should be data-based, rational, and not driven by short-term political expediency.
Now, back to Japan and Fukushima…
- TEPCO says they have successfully started a spent fuel pool cooling system for unit #1. This is the last of the SPFs to have a stable cooling system operating. All SPF temperatures are between 33 oC (unit #3) and 42 oC (unit #1).
- Mainichi Shimbun reports the on-again, off-again waste water treatment system has had it’s first week-long, non-stop period of operation. It had a 77.5% system efficiency for the period, almost it’s upper design-level. The week ending August 9 witnessed decontamination of 6,500 tons of liquid, which is considerably higher than the recently revised TEPCO goal of 5,040 tons per week. The probable reason for the significant improvement is the removal of a metal pipe that repeatedly clogged with sludge, and replacement with a heavy-duty plastic pipe that is less prone to clogging.
- TEPCO analyses of water-borne Cesium contamination from two key locations at Fukushima Daiichi continue to show a peculiar downward trend. The waste waters in all four sets of turbine building sub-drains have not only dropped close to the government limit, but at this rate will be undetectable by September. In addition, the sea waters contained inside the “quay” next to the plant continue to diminish in cesium levels and are approaching government standards. The Cesium isn’t magically going away. It must be going somewhere, and it isn’t the open ocean because samples there continue to be totally clean. Study of this phenomena could produce new evidence concerning the environmental properties of Cesium. Is anyone looking into this?
- Japan Today reports construction of the giant, nearly 12,500 m2, heavy plastic enclosure around unit #1 reactor building is finally underway. The essentially modular construction has been delayed because of debris removal around the base of the building, and detailed radiation level scans around the base of the building where workers will spend the most time. Japan Times calls the enclosure a “tent”, which suggests something amateur or “backyard”. Study of what is being built gives a very different perspective.
- Japan Times reports that the first tested samples of rice grown in Chiba Prefecture are totally free of Cesium contamination. The Prefecture is adjacent to, and south of Fukushima Prefecture. This seems to come as a surprise, but it shouldn’t. First, the wind directions during the major releases of airborne activity from Fukushima were away from Chiba, with winds varying between westerly, northerly, and easterly. The most-often direction, if you will, was easterly and blowing out to sea. The next most-often was north-westerly, blowing the contaminated plume over the area now known to have the highest surface contamination levels. With winds blowing toward Chiba only on brief occasion during the first ten days of the accident, it would be surprising if any of Chiba’s rice has detectable Cesium, let alone exceed government standards.
- Japan’s Nuclear Safety Commission has deleted all their on-line records of the thyroid-Iodine levels found in Fukushima children. They have been studying 1,000 children below the age of 15 since March, and posted the results for March exposures. Suddenly, they are all gone! NHK World says the information was deleted after the posting of a single child’s thyroid-Iodine exposure of 35 millisieverts. This is greater than the 20 millisievert exposure limit for children that has been under heavy fire for two months. One critic, a Tokyo college professor, says the deletion so soon after posting of the child’s reading is suspicious and smells of an attempt to avoid negative Press. The NSC countered by saying they deleted the data since it contained the addresses of the child, which they felt was possibly illegal. Regardless, it gives the public yet another reason to distrust their government.