- Tepco has discovered that one of its underground water reservoirs has leaked. It has triggered a news-frenzy in Japan. The water in the cistern comes from the waste water decontamination system and has been stripped of its radioactive Cesium. Some 60 other radioactive isotopes also remain in the water in various concentrations. The cistern holds about 3.2 million gallons, is 185 feet long, 160 feet wide and about 20 feet deep. The pool’s walls are made of a triple layer of waterproof sheeting. Tepco estimates about 30,000 gallons have been lost. Most of the leaked water has been contained in between the layers of the waterproof sheeting, but a small amount may have seeped through and into the surrounding earth around other giant underground pit. A soil sample taken adjacent to the reservoir contains 0.05 Becquerels per cubic centimeter. This abnormal reading caused Tepco to suspect the leak and investigation ensued. It took two days to sample the waters between the waterproof sheets. When the water between the 1st and 2nd layers was found to hold 2,200 Bq/cm3, the leak was confirmed. There is quite unlikely any of the leakage has reached the sea. Tepco’s Masayuki Ono said, “As the height of the water storage facility is relatively low, we think it’s unlikely that the polluted water mixed into underground water and reached the sea 800 meters away.” He added, “It is the largest amount of radioactive substances that has been leaked” since cold shutdown was declared in December 2011. Tepco is transferring the 3.25 million gallons remaining in the cistern to another one nearby. During the transfer, Tepco estimates as much as an additional 12,000 gallons might leak out. On Sunday, an adjacent underground reservoir was suspected of leaking. A slightly increased level of radioactivity in the soil near the second cistern indicated a possible leak, but the water level in the pool has not changed and Tepco says the leak must be very small. Regardless, Tepco plans on transferring water out of the second reservoir once the first transfer is completed. (The Japan News; Tepco News Release; Nikkei.com; Mainichi Shimbun; Japan Times; NHK World; Jiji Press)
- The Japan News says Tepco has underestimated the first leak’s radiological release. Tepco’s report of the total radioactivity lost from the reservoir and now located between the layers of pool sheeting is 0.7 trillion Becquerels. The paper says Tepco used the 6,000 Bq/ml numbers that their initial analysis of the between-layers water indicated, not the 2,200 Bq/ml now being posted. The newspaper says they should use the concentration found inside the pool itself to make the estimate – 290,000 Becquerels/ml. This would inflate the total for a potential release to 35 trillion Becquerels, which increases the estimate by a factor of fifty. Japan News (formerly Yomiuri Shimbun) says, “The impact of the leak could also be much bigger than Tepco’s estimate.” Prof. Hideo Yamazaki of Kinki University said: “I cannot understand why TEPCO used a lower figure as the basis for this calculation. Such calculations should be conducted strictly from the viewpoint of ensuring safety.” While neither calculation method is mathematically incorrect, Japan News seems to overlook their report made the previous day (Saturday). In it, a diagram clearly shows the three waterproof plastic sheets are not the only barriers between the pool’s water and the environment. There is a thick layer of “special soil” surrounding the entire reservoir “to help prevent contaminated water from seeping through.” It also shows where Tepco has sampled the water in the ground, outside the “special soil” layer. Tepco’s analysis for that sample is 0.05 Becquerels per milliliter (cubic centimeter). Using this soil-water concentration, it seems the total release estimate (if all 120 tons seeped out) could be reduced to about 9.5 million Becquerels…which would also be mathematically correct. Which number should Tepco and Japan News be using in the interest of “insuring safety”, considering the psychological damage being done? That’s for you to decide.
- There was a brief power loss to one SFP cooling system at Fukushima Daiichi on Friday. The temporary switchboard to spent fuel pool #3’s cooling system tripped off-line on Friday. Power to the system was resumed in three hours. The SFP temperature was 15oC and raised a mere 0.2oC during the power loss. At that rate, the pool would have reached the upper technical threshold of 65oC in two weeks. Regardless, the Press treated it like it was a meltdown precursor. Here’s what happened. Wire mesh was being installed below the switchgear to keep small animals from accessing the wiring and possibly chewing through it. An invading rat was the cause of last week’s multi-SFP system power loss that had the Japanese Press in an uproar. During the mesh installation, a technician inadvertently touched at least two energized contacts with the mesh at the same time, causing a short-circuit. (Jiji Press; Kyodo News) The pool contains 514 fuel bundles, 52 of which are new and unused. Radiation levels in and around unit #3 did not change. (NHK World) Meanwhile, the bulk of Japan’s new media outlets have been less than reasonable in their reporting. The reports reiterated the speculations and exaggerations that followed last month’s “rat” event, posting that if the pool had run dry another massive radiation release would have happened, if not worse. Nowhere was it said that for a pool to dry out, the staff at F. Daiichi would have to ignore everything for two weeks. The Press also used the occasion to remind everyone of the triple meltdown accident of March, 2011, the subsequent government-mandated evacuation of about 70,000 people out to 30 kilometers from the nuclear station, plus the 90,000 outside the exclusion zone who fled because they feared radiation. Then there’s the ubiquitous use of the misleading term “makeshift” relative to the temporary power supplies, reactor cooling water supplies and waste water cleanup systems, used as “evidence” of an alleged never-ending hazard posed by F. Daiichi. Because of the brief, limited power loss, The Press says the people in Fukushima Prefecture are more afraid now than ever before. For example, the Asahi Shimbun…“Fears are growing about the safety of nuclear plants, and people have periodically staged street protests.” The Mainichi Shimbun told their readers, “If the water runs dry, the fuel rods, even spent ones, will spew enormous levels of radiation.” Japan Today proclaimed, “The breakdown served as a reminder of the precarious state of the Fukushima plant. The plant…is kept stable only with makeshift systems to supply power, cool reactors and clean radioactive materials from water used as coolant.” (Japan Daily Press; Asahi Shimbun; Mainichi Shimbun; Japan Today)
- A Japanese official says F. Daiichi is still not under control. Kiyoshi Kurokawa, former chairman of the parliamentary committee to investigate the Fukushima accident (NAIIC), said this to the Diet Today. He gave the following reason, “We are unable to see what is going on with melted nuclear fuel, the concrete of reactor containers and injected cooling water.” The NAIIC has kept open the speculation of the earthquake caused the accident when they posted their report last summer because we can’t look into key areas of the plant, the worst possible suppositions cannot be dismissed and can thus be assumed. But he didn’t stop there. “There are also problems including contaminated water and a power blackout caused by a rat. Moreover, a response to victims of the crisis has not been progressing,” Kurokawa said. “The world is paying close attention to how the government will respond to problems pointed out in a report compiled by the panel.” NAIIC member Shuya Nomura, a lawyer, added that political oversight is the only way to end the on-going crisis, “Is it all right to leave the response to contaminated water and other problems to the discretion of Tokyo Electric Power Co. and the executive branch of the government? Monitoring by parliament as representatives of the public is necessary to stabilize the plant.” Another NAIIC panelist, Mitsuhiko Tanaka, a journalist, says the only way to insure full transparency is for with full government control, “I hope parliament will take initiative to open up the site of the accident.” (Jiji Press; Mainichi Shimbun)
- Japan’s Nuclear Regulatory Authority has posted safety goals for Japanese nukes. The new aims are designed to keep core damage accidents to once per 10,000 years for each reactor. In addition, the goal for serious, Fukushima-type accidents will be once per 1 million years per nuclear station. The NRA says these are essentially the same standards recommended by the U.N’s International Atomic Energy Agency, and reflect the goals used by the United States’ Nuclear Regulatory Commission. As for radiological releases, the venting of steam from inner containment structures will be once per 100,000 years, and a release of less than 100 terabecquerels per venting. This would be about 1% of what was released by the Fukushima accident. Combined, the new rules should limit the serious contamination of the environment to once every million years. Beginning in December, the NRA will obligate all plants to run detailed accident probabilities. Any plant not meeting these goals will not be allowed to operate. (The Japan News…formerly the Yomiuri Shimbun)
- The NRA has also said that new anti-terrorist safety facilities need not be completed for 5 years. Anti-terrorist measures will include building a back-up control room for each plant, in the event that the regular one is not functional or otherwise comes under terrorist control. The back-up control room will be located in a separate building at least 100 meters from the reactor plant’s operations buildings. The distance is intended to prevent a single accident event from preventing both locations from functioning. Control functions will include remote operations of all emergency cooling systems. During the 5-year interim, plant operators must install “mobile facilities” to handle the emergency functions before any restarts can be allowed. (Mainichi Shimbun)
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