By ENENEWS ADMIN
Tepco: 68 tons of nuclear fuel melted at Fukushima Reactor No. 1
[…] The nuclear fuel at the No. 1 reactor melted as its temperature reached nearly 3,000 C at one time, TEPCO estimated. In the No. 1 reactor, TEPCO believes, almost all of the about 68 tons of fuel melted. […]
Only 37 centimeters of concrete remains between the fuel and the vessel’s outermost steel wall in the most damaged area, TEPCO said.
Without water, the No. 1 reactor’s fuel temperature was more than high enough to have melted everything inside the pressure vessel, not only the fuel itself but also the fuel control rods, the utility said.
TEPCO currently maintains a steady supply of water to the three reactors, enabling the No. 1 reactor to always have about 40 centimeters of cool water at the bottom of the containment vessel, enough to cover the melted fuel, according to the utility. […]
First radiation limit set for school meals
Threshold set at 40 becquerels for food, drinks in 17 prefectures
The government has instructed the boards of education of 17 eastern and northeastern prefectures to set the upper limit on radioactive substance exposure for food and drink served in school meals at 40 becquerels per kilogram, officials said Thursday.
The directive on meals offered at elementary and junior high schools is the first issued by the central government since the Fukushima nuclear crisis was triggered by the March 11 earthquake and tsunami.
The threshold is one-fifth of the current provisional limit on radioactive cesium for items of general consumption — 200 becquerels per kilogram for drinking water, milk and dairy products.
The maximum allowable amount for rice, vegetables, meat and fish is set at 500 becquerels per kilogram.
The officials of the Ministry of Education, Culture, Sports, Science and Technology said they newly set the criteria for school meals as the government plans to lower the upper limit of annual internal exposure to radioactive cesium through food and drink consumption to 1 millisievert from the current provisional threshold of 5 millisieverts.
The 17 prefectures include Fukushima, Iwate, Miyagi, Ibaraki, Tokyo, Niigata, Yamanashi, Nagano and Shizuoka.
The ministry has earmarked about ¥100 million in the third extra budget for the current fiscal year to cover part of the cost to purchase dosimeters to detect radiation amounts in meals at schools in the 17 prefectures, according to the officials.
Under the directive, municipal governments are requested to buy equipment that can detect radiation levels in food and drink below 40 becquerels and to stop serving items with radioactive substances that exceed the upper limit, the officials said.
MHLW ignores the medical statistics of Fukushima and a part of Miyagi
Ministry of Health, Labor and Welfare (MHLW) conducts a patientsurvey every 3 years.
However, it turned out that they eliminated the data of Fukushima and a part of Miyagi from their statistics this time.
Since a few weeks ago, this “harmful rumor” has been spreading on theinternet.
11/21/2011, according to the survey of medical association of each local government, since this April to October, leukemia cases have increased by 7 times over last year.
Having this result, the chairman of medical association, Haranaka Katsumasa, said that the connection between this unusual increase of leukemia cases and the Fukushima accident is not clear, but once they figure out the reason, they will announce it.
60% of the total leukemia cases are acute leukemia. This is the highest ratio since 1978, when they started taking this survey.
80% of the patients are from Northern Japan and the Kanto area. Fukushima has the highest rate while Ibaraki, Tochigi, Tokyo follow.
To clear up this “confusion”, a Japanese citizen asked Ministry of Health, Labor and Welfare for the truth, to which they replied that they take all patients statistics but that this year they eliminated the data from Fukushima and a part of Miyagi from the whole statistics report.
They say it is to support the reconstruction of Fukushima and Miyagi, but we all know that in reality abandoning the survey only makes the situation worse.
On 3/11, earthquake and Tsunami hit Miyagi and Iwate for most of the part while Fukushima suffers from radiation mostly.
If they really wanted to try to “help reconstruction efforts” (sic), they should eliminate the data of those three prefectures, with Iwate and Miyagi given a higher priority.
The Ministry of Health, Labor and Welfare does not give any more specific reasons why.
TEPCO injects nitrogen into pressure vessels
The operator of the Fukushima Daiichi nuclear power plant has started injecting nitrogen, an inert gas, into the pressure vessels of the crippled reactors to prevent another hydrogen explosion.
In late October, Tokyo Electric Power Company began extracting gases from the containment vessel of the No.2 reactor to remove radioactive substances. During the work, TEPCO found hydrogen accumulating in parts of the reactor at a density of up to 2.9 percent.
TEPCO started pumping nitrogen into the pressure vessels of the No.1, 2, 3 reactors on Thursday to lessen the concentration of hydrogen.
The density of hydrogen accumulating in the containment and pressure vessels is thought to be below 4 percent, the level where an explosion could occur.
TEPCO says the nitrogen injection will push out hydrogen and reduce its concentration.
Keeping hydrogen density low is an indispensible condition in the second step of the process decided upon by the government and TEPCO to resolve the nuclear accident. They are aiming to achieve a state of cold shutdown for the reactors by the end of the year.
The Nuclear and Industrial Safety Agency plans to assess how well TEPCO can manage hydrogen levels.
Friday, December 02, 2011 05:02 +0900 (JST)
Fukushima fuel rods eating through solid concrete
By North Asia correspondent Mark Willacy
Updated December 02, 2011 17:42:36
Molten fuel rods at the Fukushima nuclear plant may have eaten two-thirds of the way through a concrete containment base, the plant’s operator says.
The statement from TEPCO is based on a new simulation of the March meltdowns.
It says its latest calculations suggest the nuclear fuel inside the number one reactor has melted entirely.
Simulations predict the molten fuel has eaten through 65 centimetres of concrete in a containment base below, stopping just 37 centimetres short of an outer steel casing.
It is also believed that the molten core has eaten part of the way through the concrete bases of the number two and three reactors.
The findings indicate the facility came much closer to a cataclysmic meltdown than previously thought.
The operator’s assessment comes about six months after international nuclear experts warned that molten fuel could eat through containment vessels below the reactors.
Meanwhile, TEPCO has scrapped the construction of a new nuclear power station in Japan’s north.
It is the first time a new plant has been abandoned since the Fukushima disaster.
The Higashidori nuclear power plant was to have been an advanced boiling water reactor with a capacity of nearly 1.5 million kilowatts.
But TEPCO decided to abandon the construction, which was to have been finished in five years’ time.
The company is blaming the cost of compensating victims of the meltdowns at its Fukushima plant, which is expected to run into tens of billons of dollars.
(make that TRILLIONS.)
2 December 2011 15:00
Xenon 400,000 times normal found in Chiba air immediately after Fukushima nuke accident
CHIBA — Radioactive xenon-133 some 400,000 times normal levels was detected in the atmosphere here immediately after the outbreak of the crisis at the Fukushima No. 1 Nuclear Power Plant, a radiation survey organization said.
It took three months before the volume of radioactive substances returned to normal levels.
The Chiba-based Japan Chemical Analysis Center made the announcement during a radiation research session in Tokyo on Dec. 1, organized by the Education, Culture, Sports, Science and Technology Ministry.
Keisuke Isogai from the center denied that the high concentration of radioactive substance posed a health hazard.
“I think xenon-133 drifted from the Fukushima No. 1 nuclear plant to Chiba in the form of a plume. Since the detected amount translates into a cumulative external exposure to radiation of only 1.3 microsieverts over the three-month period, it won’t cause a health hazard,” he said.
The average amount of xenon-133 in the atmosphere was 1,300 becquerels per cubic meter of air in Chiba between March 14 and 22, as compared with zero to 3.4 millibecquerels before the crisis. The volume reached 400,000 times normal levels shortly after the nuclear crisis was triggered by the March 11 tsunami, according to the center.
Xenon-133 is generated in the process of nuclear fission of uranium and plutonium used as fuel at nuclear power stations. Since xenon-133 hardly reacts to any other substance, there is no fear of internal exposure to radiation even if inhaled, experts say.
(Mainichi Japan) December 2, 2011
TEPCO: Cooling stoppage info was not shared
A miscommunication between workers at the Fukushima Daiichi nuclear plant could have delayed a response to the accident on March 11th.
The operator says the plant’s chief did not know for several hours that the only backup cooling system for the Number 1 reactor was manually shut down on the day of the earthquake and tsunami.
NHK has obtained Tokyo Electric Power Company’s interim report on the accident to be released on Friday.
The report says workers in the reactor’s control room stopped an emergency cooling system shortly after 6 PM. It says the plant chief, Masao Yoshida, and others in the facility’s office building were unaware of the manual shut-down.
TEPCO says it was not until around midnight that the plant chief noticed the system was not working. A rise in the radiation levels at the reactor building alerted him to the possibility of damaged fuel rods.
The emergency system uses steam to cool down a reactor when there is no electricity supply. It was the only workable cooling system at the reactor after the plant lost its major power sources.
The report says the misunderstanding occurred because a malfunctioning gauge failed to show that the water level had dropped, exposing the fuel rods.
TEPCO estimates that damage to the exposed fuel rods occurred about 4 hours after the quake. It says this generated large amounts of hydrogen that caused the first explosion at the plant on the following day.
Friday, December 02, 2011 10:20 +0900 (JST)
TEPCO study shows water level in spent fuel pool was dangerously low
TOKYO, Dec. 2, Kyodo
A study by Tokyo Electric Power Co., operator of the crippled Fukushima Daiichi nuclear power plant, has shown that water in the No. 4 unit’s spent fuel pool temporarily dropped to a level close to exposing the stored nuclear fuel, sources close to the matter said Thursday.
After the No. 4 unit lost its key cooling functions along with the plant’s other reactors in the wake of the March 11 earthquake and tsunami, the water level in the No. 4 spent fuel pool fell at one point to only 1.5 meters above the top of the fuel assemblies, as heat from the fuel had caused the coolant to evaporate. The water level is usually around 7 meters above the assemblies.
The water level remained low for over a month until at least April 20. Workers injected around 930 tons of water into the spent fuel pool between April 22 and 27, filling up the pool, but a graph compiled by Tokyo Electric shows that the fuel would have been exposed in early May if water had not been injected.
Fukushima Earthquake Moved Seafloor Half a Football Field
The massive shift, laterally and upward, caused the epic March 2011 tsunami
By Mark Fischetti | December 1, 2011
The March 2011 Tohoku-Oki earthquake that decimated Japan and its Fukushima nuclear reactors with a monster tsunami altered the seafloor off the country’s eastern coast much more than scientists had thought. Analysis released today in the journal Science indicates the ocean bed moved as much as 50 meters laterally and 16 meters vertically. The magnitude 9.0 quake occurred close to the nearby Japan Trench that runs north to south in the Pacific Ocean (dark blue line on the map below).