Europe Solidaire Sans Frontières
High radiation readings suggest new water tank leak at Fukushima
TOKYO (Kyodo) — Very high radiation levels were observed Saturday at three tanks and one of the pipes connecting them at the crippled Fukushima Daiichi nuclear plant, pointing to the possibility that radioactive water may have newly leaked, Tokyo Electric Power Co. said.
The radiation readings were from 70 to 1,800 millisieverts per hour, although none of the tanks showed any visible drop in their water levels, the plant operator said, adding it is investigating the cause.
The tanks are built of steel plates held together by bolts, the same structure as the tank that was found last week to have leaked 300 tons of highly toxic water.
Traces of water leakage were found below the pipe where 230 millisieverts per hour was measured, it said.
The utility also said that 900 becquerels per liter of tritium had been detected at a water well to pump groundwater before it reaches a reactor building, compared with 450 becquerels per liter recorded in February.
As the well is located near the “H4” area where the tank confirmed to have leaked stands, TEPCO is investigating if the rise in the tritium level is related to the leakage of toxic water.
On Sunday, the utility said it had detected 920 becquerels per liter of radioactive substances emitting beta rays, such as strontium-90, in a drainage ditch located south of the H4 area, compared with 580 becquerels recorded on Aug. 22. The drainage ditch leads to the Pacific.
Kyodo News, September 2, 2013
http://mainichi.jp/english/english/newsselect/news/20130902p2g00m0dm001000c.html
More tank leaks found at Japan nuke plant
TOKYO (AP) — Japan’s top nuclear regulator has raised safety concerns about hastily built storage tanks and their foundations amid reports of new leaks of radiation-contaminated water.
Nuclear Regulation Authority Chairman Shunichi Tanaka said Monday that a small leak and signs of possible leaks have been spotted at several other Fukushima Dai-ichi storage tanks. Officials say part of the leak has escaped into the sea.
He said the discoveries were the result of closer inspections after a 300-ton leak two weeks ago. Tanaka raised concerns about the tanks’ foundations and urged careful monitoring.
The plant’s operator says it suspects other possible leaks because radioactivity has been detected near the tanks, although it is not considered deadly.
The latest leaks have triggered further concerns about the plant’s ability to manage the contaminated water.
Kyodo News, September 2, 2013
http://mainichi.jp/english/english/newsselect/news/20130902p2g00m0dm069000c.html
High radiation levels detected in water leaking from Fukushima plant tank pipes
High levels of radiation have been detected in water leaking from pipes connecting tanks holding contaminated water at the crippled Fukushima No. 1 Nuclear Power Plant, it has been announced.
Tokyo Electric Power Co. (TEPCO), the operator of the plant, said on Sept. 1 that 300 million becquerels of radiation per liter was detected in water leaking from the tank-connecting pipes in the plant’s “H5” area.
The announcement came following the detection of up to 230 millisieverts per hour of radiation underneath those pipes. TEPCO said on Sept. 1 that the radioactive water drops “are believed to be leaks of contaminated water.”
TEPCO says it found on Aug. 31 that one drop of water every 90 seconds was leaking from the connections between the tanks and pipes, leading the utility to close the tanks’ valves.
Mainichi Shimbun, September 2, 2013
http://mainichi.jp/english/english/newsselect/news/20130902p2a00m0na005000c.html
Nuke plant design dependent on power sources a mistake: experts
The design of the crippled Fukushima No. 1 nuclear power plant that took power supply for granted was a “fundamental mistake” leading to the nuclear disaster, the Atomic Energy Society of Japan (AESJ) has announced.
An accident investigation panel under the AESJ, which has been investigating the Fukushima nuclear disaster since June last year, released an outline of its draft final report on the disaster during a meeting held in Tokyo for AESJ members on Sept. 2.
In the draft of its final report, the panel comprising some 50 experts called it a “fundamental fallacy” that “all functions (at the plant) presupposed the presence of power sources” in terms of equipment and other designs.
As to why the isolation condensers (IC) in the reactor building of the plant’s No. 1 reactor failed to function, leading to a hydrogen explosion, the panel blamed a lack of awareness and experience among plant workers about the IC functions.
The draft report also cited a lack of preventive measures against the tsunami and severe accidents prior to the disaster as the direct cause of the nuclear catastrophe.
“The disaster could have been averted if measures against the tsunami and severe accidents had properly been implemented,” the draft report said, adding, “Experts had been withdrawn in their own narrow fields of expertise and overlooked safety as a system.”
With regards to on-site responses to the disaster, the report said, “Although there were some issues, there is a limit to what human beings can do in such extreme situations, and overall their responses were above regular standards.”
The panel will also present the draft report at a convention to be held in Aomori Prefecture from Sept. 3, before compiling a final report based on AESJ member feedback by the end of the year.
Mainichi Shimbun, September 2, 2013
http://mainichi.jp/english/english/newsselect/news/20130902p2a00m0na008000c.html
Radiation spike at Fukushima plant raises fears of new toxic water leak
Radiation levels of over 100 millisieverts per hour have been detected at the base of another storage tank at the Fukushima No. 1 nuclear plant, plant operator Tokyo Electric Power Co. (TEPCO) announced Sept. 2.
The high radiation level has raised fears of yet another radioactive water leak at the plant. There have been suspected leaks in four areas of the plant ground so far.
The new radiation spike was found at the base of a storage tank about 100 meters to the south of another tank that leaked some 300 metric tons of radioactively contaminated water earlier this year. The new radiation hotspot was discovered by a maintenance patrol on Sept. 2, though there was no sign of a leak at the base of the tank.
Mainichi Shimbun, September 3, 2013
http://mainichi.jp/english/english/newsselect/news/20130903p2a00m0na020000c.html
Radiation near tanks hits highest level yet
Tokyo Electric Power Co. has detected the highest radiation levels found so far near tanks holding contaminated water used to cool reactors at its wrecked Fukushima No. 1 nuclear plant.
Readings of 2,200 millisieverts (2.2 sieverts) per hour were found Tuesday in an area where levels of 1,800 millisieverts had been detected Saturday, Tepco spokeswoman Mayumi Yoshida said Wednesday. The increase could be due to a slight difference in where the measurements were taken, she said.
“It fluctuates when you move a little bit,” so the higher reading doesn’t necessarily indicate rising radioactivity levels, Yoshida said.
Tuesday’s hourly reading is equivalent to the amount of radiation 44 plant workers may be exposed to in a full year under government guidelines.
A report on the weekend said exposure to 1.8 sieverts could prove fatal in around four hours.
The Tuesday reading was at one of four radiation hot spots near storage tanks reported by Tepco last weekend, one of which led crews to a leaking pipe that was fixed Sunday. Investigators will now deploy more advanced sensors to locate the source of Tuesday’s reading, Yoshida said.
Tepco reported a 300-ton leak last month from a tank used to store radioactive water in what the Nuclear Regulation Authority designated the most severe level since the March 2011 earthquake and tsunami sparked a triple meltdown at the plant.
The utility has subsequently boosted the number of tank-inspection patrols from twice to four times a day and increased its inspection staff to 60 members from 10, it said.
Bloomberg, September 4, 2013
http://www.japantimes.co.jp/news/2013/09/04/national/radiation-near-tanks-hits-highest-level-yet/#.Ui2W_H9jbRY
Leaked toxic water at Fukushima plant may have mixed with groundwater
TOKYO (Kyodo) — Tokyo Electric Power Co. said Thursday it has detected 650 becquerels per liter of radioactive substances from groundwater near a leaky water storage tank at its crippled Fukushima Daiichi nuclear power plant.
The detection of radioactive substances emitting strontium and other beta rays shows the possibility that toxic water from the tank may have reached the groundwater, the plant operator known as TEPCO said. About 300 tons of highly toxic water had leaked from the tank.
The utility said it collected the groundwater Wednesday at a well dug more than a dozen meters south of the tank in the H4 area where the radioactive water had leaked.
The radiation level of the groundwater, which has been found to be lower than that of the toxic water in the tank, may have been diluted by rain water, according to TEPCO.
The utility believes that leaked toxic water mostly seeped into soil and partly flowed into the sea through a nearby drain ditch. The amount of flow into the sea is unknown.
The government plans to use wells to pump up groundwater before it flows into reactor buildings for discharge into the sea in a bid to reduce about 400 tons of groundwater now seeping into reactor buildings every day. The construction of an ice wall is also planned to block off groundwater flow.
With the latest detection of radioactive substances, however, the water in some of the wells is feared to be contaminated.
Kyodo News, September 6, 2013
http://mainichi.jp/english/english/newsselect/news/20130906p2g00m0dm009000c.html
Oi Plant
No. 3 reactor at Oi plant to be suspended for routine checks
TSURUGA (Kyodo) — Kansai Electric Power Co. will suspend the No. 3 reactor at its Oi nuclear power plant in Fukui Prefecture on Monday afternoon for mandatory routine checks.
The No. 4 reactor at the plant will also be suspended on Sept. 15, halting Japan’s nuclear power supply again for the first time in around 14 months. The two reactors are the only units currently online in Japan.
It will be the second time for all 50 commercial reactors in Japan to be offline since the 2011 Fukushima Daiichi plant disaster heightened public concern over the safety of nuclear power.
Nuclear reactors in Japan are required to undergo periodic inspections every 13 months.
It is not known how long the routine checks will take to complete.
Last year, Japan experienced a period without nuclear power for the first time in over 40 years in the wake of the Fukushima nuclear crisis. The period lasted about two months as the government decided in June to allow the restart of the two Oi reactors to address possible power shortages in the summer in western Japan.
Kyodo News, September 2, 2013
http://mainichi.jp/english/english/newsselect/news/20130901p2g00m0dm100000c.html
No active fault under Oi plant, NRA team says
A team from the Nuclear Regulation Authority said Monday that no active geological faults exist under the key facilities of the Oi nuclear power station in Fukui Prefecture.
The five-member team reached its conclusion after inspecting the Kansai Electric Power Co. facility from November to July and determining that the ÅgF-6 crush zoneÅh fault under one of the facilities is not active.
NRA Commissioner Kunihiko Shimazaki, who personally led the team, said an effective consensus had been formed and that further discussions will be held before it drafts its report to the NRA. The future talks will involve outside experts, he said.
The No. 3 and No. 4 units at Oi are JapanÅfs only active commercial nuclear reactors. No. 3 was set to be taken offline Monday for a routine checkup and will be followed by No. 4 on Sept. 15, marking only the second time Japan has without atomic power.
To ensure the reactors can be restarted as soon as possible after the checkups, Kansai Electric applied in July for an NRA inspection of the Oi complex under new nuclear safety standards drafted after the Fukushima crisis, which began in March 2011 at Tokyo Electric Power Co.Åfs Fukushima No. 1 power station in Fukushima Prefecture.
But the new nuclear watchdog hasnÅft yet started the inspection because it was busy conducting research on faults and crush zones under the Oi plant. It is now known how long the inspection of the Oi plant will take.
Jiji Press
, September 3, 2013
http://www.japantimes.co.jp/news/2013/09/03/national/no-active-fault-under-oi-plant-nra-team-says/#.Ui2N6n9jbRY
Twitter
Facebook