Sea radiation leaks reach 15,000 terabecquerels off Fukushima plant

TOKYO (Kyodo) — Researchers estimate that amount of radioactive substances that leaked into the sea from the crippled Fukushima Daiichi nuclear power plant between March 21 and April 30 totaled 15,000 terabecquerels, an entity which led the research work said Thursday.

The estimate compares with 4,700 terabecquerels of radioactive iodine and cesium that the plant operator, Tokyo Electric Power Co., estimated had leaked into the sea between April 1 and 6 from a water inlet at the No. 2 reactor at the four-reactor plant following the March 11 earthquake and tsunami.

The big gap indicates radioactive substances could have leaked through other channels as well as the No. 2 reactor inlet, said Takuya Kobayashi, a senior researcher at the Japan Atomic Energy Agency which led the estimate work.

The researchers’ estimate will be reported at a meeting of the Atomic Energy Society of Japan starting Sept. 19 in Kitakyushu, Fukuoka Prefecture.

Kyodo, September 8, 2011
http://mdn.mainichi.jp/mdnnews/national/archive/news/2011/09/08/20110908p2g00m0dm109000c.html

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Nuclear experts: Radiation-contaminated areas in Fukushima disaster only one-tenth of Chernobyl’s

The Atomic Energy Society of Japan (AESJ) suggests in a recent survey that the total area of radioactive contamination following the nuclear meltdowns in Fukushima in March equaled no more than one-tenth of that in the Chernobyl accident in 1986.

The survey shows that approximately 800 square kilometers is contaminated with levels of radioactive cesium exceeding 600,000 becquerels per square meter, whereas in Chernobyl the total area exceeding 555,000 becquerels per square meter topped 10,000 square kilometers. Based on these results, the Society’s nuclear experts estimated that radiation contamination area in the Fukushima disaster equals no more than one-tenth that in the Chernobyl disaster.

Meanwhile, a soil radiation map of over 2,200 locations within a 100-kilometer radius of the Fukushima No.1 Nuclear Power Plant, released by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) on Aug. 29, shows 34 locations with levels of cesium exceeding 1.48 million becquerels per square meter, the level used as the basis for issuing compulsory evacuation orders in areas near the Chernobyl plant.

According to experts at the Ibaraki Prefecture-based National Institute for Agro-Environmental Sciences — in charge of monitoring rice fields in 15 locations across the country — previously the most severe soil radiation in the history of Japan was measured in 1967 at 138 becquerels per kilogram, following a series of nuclear experiments in the 1960s.

A map showing levels of radioactive cesium (cesium-137 and cesium-134) in all surveyed zones is regularly updated on MEXT’s website, while online map search sites such as www.geocoding.jp allow users to pinpoint particular monitoring locations.

Mainichi Shimbun , September 8, 2011
http://mdn.mainichi.jp/mdnnews/national/archive/news/2011/09/08/20110908p2a00m0na008000c.html

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Cesium found in mushrooms in 43 Fukushima municipalities; gov’t bans shipments

FUKUSHIMA — The Japanese government on Sept. 15 ordered the suspension of all shipments of wild mushrooms from 43 Fukushima Prefecture municipalities, after radioactive cesium exceeding the legal limit was detected.

The ban applies to wild mushrooms from all municipalities in eastern and central Fukushima Prefecture, and the town of Inawashiro in the west of the prefecture, after samples from the areas yielded cesium contamination over the 500-becquerel-per-kilogram limit.

Mushroom farmers in the 16 municipalities in the Aizu region of western Fukushima Prefecture that were not affected by the ban were also urged to refrain from harvesting until solid data confirms the mushrooms’ safety.

A ban on the consumption of wild mushrooms was also issued to residents in the city of Iwaki and Tanagura in the east of the prefecture, after 6,200 to 28,000 becquerels of radioactive cesium was detected in tawny milkcap mushrooms.

Until now, among the two main types of wild mushrooms — those that grow from roots in the soil, and polypores, which usually grow on wood — high levels of radioactive cesium were reported only in the first type. On Sept. 6 the government banned shipments of all root-grown “saprophytic fungi” mushrooms in the two Fukushima Prefecture towns of Tanagura and Furudono. This time, however, anticipating consumers’ difficulties in distinguishing between the two types, the government decided to ban all shipments of wild mushrooms.

The ban, however, does not apply to shipments of cultivated mushrooms, government officials said.

Mainichi Shimbun , September 16, 2011
http://mdn.mainichi.jp/mdnnews/national/archive/news/2011/09/16/20110916p2a00m0na016000c.html

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Above-the-limit cesium found in Iwate beef, 1^st since shipments OK’d

MORIOKA (Kyodo) — Radioactive cesium exceeding the legal limit has been detected in beef cattle in Iwate Prefecture for the first time since the ban on shipments in the region was lifted last month, local officials said Thursday.

The amount of cesium found topped the government-set allowable limit of 500 becquerels per kilogram in two of eight beef cattle following shipment, the officials said.

Cesium was first detected in the eight cattle in a simple test Tuesday, the officials said, adding that two of the eight were destroyed after further tests confirmed they had excessive levels of the element.

The cattle shipment ban was imposed following the discovery of beef contaminated with radioactive cesium from cattle raised in northeastern Japan, in the wake of the nuclear crisis at the Fukushima Daiichi power plant triggered by the March 11 earthquake and tsunami.

Kyodo, September 8, 2011
http://mdn.mainichi.jp/mdnnews/national/archive/news/2011/09/08/20110908p2g00m0dm107000c.html

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Most core detectors found damaged at Fukushima No. 1 reactor

TOKYO (Kyodo) — Tokyo Electric Power Co. said Friday most of the detectors lying below the pressure vessel at the No. 1 reactor of the crippled Fukushima Daiichi nuclear power plant that check the condition of the control rods have been found damaged.

The damage — mostly burnt wiring or electrical shortages — is believed to have been caused by the intense heat in the wake of a core meltdown.

The utility conducted current tests on the detectors, which each cover 97 control rods, and found only one detector functioned normally, it said.

Junichi Matsumoto, a senior official at the utility, said he believes the detectors suffered such damage as both pressure and temperatures exceeded the given design limits for the pressure vessel.

Kyodo, September 16, 2011
http://mdn.mainichi.jp/mdnnews/national/archive/news/2011/09/16/20110916p2g00m0dm112000c.html

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TEPCO builds frames for cover over Fukushima reactor

TOKYO (Kyodo) — The operator of the crippled Fukushima Daiichi nuclear power plant said Saturday it has built a framework of a giant covering for the No. 1 reactor to prevent radioactive materials from spreading and stop rainwater from entering the reactor building.

Tokyo Electric Power Co., known as TEPCO, said it plans to complete the covering, a tent-like structure made of steel frames and air-tight polyester sheets, by the end of October.

When completed, the covering will be between 42 and 47 meters long and about 54 meters high.

The building housing the No. 1 reactor and those housing the Nos. 3 and 4 reactors at the plant were badly damaged due to explosions after tsunami caused by a magnitude 9.0 earthquake struck the plant on March 11.

Once the installation is completed at the reactor, TEPCO will consider installing similar coverings for the Nos. 3 and 4 reactors, according to the operator.

Kyodo, September 11, 2011
http://mdn.mainichi.jp/mdnnews/national/archive/news/2011/09/11/20110911p2g00m0dm005000c.html

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