- JAIF reports TEPCO is sending workers into reactor building #3 to visually inspect piping for damage. The robot sent into the building earlier this week showed images of “limited damage” to pipes and valves. The workers will be able to make assessments that are more comprehensive than the robot. The goal is to find if possible flow paths for cooling water to #3 reactor exist other than the path currently being used. TEPCO feels one reason why unit #3 water injection is twice the flow of either unit #1 or #2 is leaks in the present flow-path piping which reduces the amount of water actually getting to the RPV. If they find an alternative flow path which is relatively undamaged, they will switch to it and see what happens. If a new path cools the RPV more efficiently than the existing path, they will be able to reduce the amount of water used to cool unit #3 and use less decontaminated water each day.One limiting factor in the worker’s visual inspection is “stay time”. Stay time is the amount of time a person can stay in a building or area before approaching an exposure limit. The robot sent into unit #3 measured relatively high exposure rates, which should come as no surprise to anyone. However, the robot’s measurements covered all floors, up to the demolished refueling deck, giving the Health Physics staff a better idea of the intensity of radiation fields and how they vary from floor-to-floor and location-to-location. With this data, calculations of “stay time” can be made with confidence. The radiation levels in reactor building #3 show that each person entering the structure will be limited in how much actual inspection can be done. Once a “stay time” is approached, that person leaves and is replaced by someone else to resume the inspection where the first person left off. To insure against inadvertent over-exposure, each worker wears personal dosimetry intended to allow them to keep an eye on the exposure they are receiving while it happens.
- Yomiuri Shimbun reports that the volume of water decontaminated at Fukushima has been 29,000 tons. Yet, in the same article the newspaper judges the water cleanup system a failure. Very curious. Further in the article it is said the typhoon last week raised the waste water level 3,000 tons and the total now stands at 120,000 tons of contaminated water. Did they forget to subtract the 29,000 tons that have been decontaminated?
- The beef-phobia in Japan continues to spiral out of control. Last week, all beef shipments from Fukushima Prefecture were banned indefinitely by the Tokyo government because about 1% of the cattle were tested to have Cesium-134 levels in their meat above health standards. None of them, however, had levels more than twice the standard. Now, neighboring Miyagi Prefecture has had their beef shipments banned because 6 out of the more than 1100 cattle tested have above-standard Cesium levels in their meat. As in Fukushima, all six have levels less than twice the standard. The all-beef-ban from the two prefectures is because of “fears of radioactive contamination” (NHK World). In other words, if Cesium levels are detectable, most people won’t want to buy the beef. Whether or not the Cesium-detectable beef is actually safe to eat makes no difference.
- The Japanese government and the majority Democratic Party want all debris caused by the tsunami, but contaminated by Fukushima isotopes, disposed of by the government. All tsunami debris more radioactive than government standards will be handled as radioactive waste, very little of which should qualify as high level waste. Debris below government radioactive standards will be turned over to Prefectural governments to dispose of as regular waste. In the bill to be presented to the Diet, TEPCO will be forced to pay for the disposal of radioactive debris above the existing standard.
- The United Nations opened its 23rd Conference on Disarmament in Matsumoto City, Japan, Wednesday morning. In his keynote speech, IAEA chairman Yukiwa Amano said Fukushima Daiichi is one of the most serious and complicated crises ever faced by the human race, thus the conference will focus both on nuclear disarmament and nuclear safety. We are very disappointed that the U.N. and IAEA are reinforcing, if not promoting, pre-existing world-wide public confusion between reactors and bombs. Combining the issues makes it seem like there is a real connection between the two, when none actually exists. For more on this, see “The Uranium Explosive Myth” and “Confusion About Fallout” pages in the menu (left).
- The radioactive contamination levels in the turbine building drainage trenches at Fukushima have been dropping for months. Up until mid-June, the decreases had been due to the radioactive die-off of Iodine-131. Since then, the levels have continued to drop with respect to Cs-173 and Cs-134. While the I-131 die-off was due to its relatively short half-life of 8 days, the Cesium isotopes both have half-lives measured in years. They will not burn out at a detectable rate. There must be some reason that their concentrations are more than a thousand times less than in March. Levels are currently in the 1-3 Bq/ml range (between one and three radioactive disintegrations per second). If this trend continues, Cesium levels in the trenches will be non-detectable in no more than 60 days (maybe as short as 30 days). Research into this phenomena could be a boon to everyone in Japan concerned about Cesium-contaminated soils and waters. Is anyone in Japan looking at this?In addition, we have found a possible comparison between the Cesium levels reported with Fukushima and a common household item. A typical home “ionizing” smoke detector contains a radioactive source which has ~37,000 becquerels of activity (37,000 radioactive disintegrations per second). While the source is Americium-241, not Cesium, it at least gives everyone an idea of how small the Cesium levels in the Fukushima trenches actually are.
- Japan’s Chemical Analysis Center has been regularly analyzing the soil from three locations near the Fukushima plant site, each about 500 meters from unit #2 which is the physical center of the three fuel-damaged reactors. All are outside TEPCO property. The radioactive concentrations are high (>1,000 Bq/cm3).But, something interesting is to be found in their analysis. Out of more than 40 possible fission-created elements produced in the reactors at Fukushima, only 4 seem to have found their way into the soil and but three remain. Iodine was one of them, but its short half life (T1/2) has caused it to decay into oblivion by the end of June. What presently remains is Cesium (CS-134 and Cs-137), Tellurium (Te-129 with a 34 day T1/2), and Silver (Ag-110 with a T1/2 of ~250 days).SILVER? Yes…that and the entire spectrum of rare earths are part of the fission product inventory. All of the rare earths have half lives short enough to be a valuable resource 50 years after the spent fuel cells are removed from the reactor. Now, is that really a waste material? (see “Nuclear Waste : Is It?” in the menu – left)
- TEPCO has pumped more water into the Steam Dryer and Moisture Separator pool in the floor of the decimated unit #4 refueling deck of its reactor building. The more water that covers the neutron-activated internal reactor components, the lower the radiation levels will be on the deck itself. Water is a great radiation exposure reducer. For every additional foot of water, the radiation level will drop by a factor of ten. A filled pool could greatly increase the stay times of workers removing debris from the March 15 hydrogen explosion.
- The governor of Niigata Prefecture, home of three currently-idled nukes, has said he will not allow restarts even if all three pass the government’s “stress tests”. He finds it impossible to allow resumption of operations under what he calls “fabricated safety” associated with stress tests he judges to be “almost useless”. Governor Hirohiko Izumida adds that the stress tests do not address the causes of the accident at Fukushima, and he will not extend restart approval until the causes are adequately addressed.While we feel he is naively denying needed power to the already stressed energy situation in Japan, we agree with his reasons…sort of agree, anyway. It seems Izumida wants tsunami protection beefed up and emergency power reliability upgraded at all nukes, neither of which is assumed to be part of stress testing itself. We agree. However, the true causes of the situation at Fukushima are almost entirely bureaucratic, and one instance of it needs fixing immediately. Specifically, procedural bureaucratic delays with respect to implementing emergency actions which would protect the integrity of the fuel cell, must be eliminated. The Fukushima plant manager decided full depressurization and venting of unit #1 was essential just after midnight of March 12. If he could have vented immediately, radioactive releases to the environment would have been in the innocuous Three Mile Island range and the fuel cell would not have had a complete, core-relocating meltdown. The Hydrogen explosion would probably not have happened. Control room records from the first five days at Fukushima show that the unit #1 hydrogen explosion started an unbreakable chain of events that doomed reactors #2 and #3, and possibly made the hydrogen explosions at units 3 & 4 inevitable. The Plant Manager could not begin necessary venting of unit #1 until he got approval from TEPCO in Tokyo, and they would not approve without the consent of the Prime Minister. All-in-all, these bureaucratic road-blocks caused a delay of more than nine hours before venting could begin. At that point, unit #1 had passed the point of no return. Insufficient tsunami barriers and inadequate emergency power reliability were not the ultimate problem. We say, fix the politics before it happens again!
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