The radiation level in the containment vessel of reactor 2 at the crippled Fukushima No. 1 power plant has reached a maximum of 530 sieverts per hour, the highest since the triple core meltdown in March 2011, Tokyo Electric Power Co. Holdings Inc. said.
Tepco said that the blazing radiation reading was taken near the entrance to the space just below the pressure vessel, which contains the reactor core.
The high figure indicates that some of the melted fuel that escaped the pressure vessel is nearby.
The recent reading, described by some experts as “unimaginable”, is far higher than the previous record of 73 sieverts an hour in that part of the reactor.
A single dose of one sievert is enough to cause radiation sickness and nausea; 5 sieverts would kill half those exposed to it within a month, and a single dose of 10 sieverts would prove fatal within weeks.
New photographs show what may be melted nuclear fuel sitting under one of Japan’s wrecked Fukushima reactors, a potential milestone in the search and retrieval of the fuel almost six years after it was lost in one of the worst atomic disasters in history.
Tokyo Electric Power Co. Holdings Inc., Japan’s biggest utility, released images showing a grate under the Fukushima Dai-Ichi No. 2 reactor covered in black residue. The company, better known as Tepco, may send in a scorpion-like robot as soon as February to determine the temperature and radioactivity of the residue.
The melted fuel has since come in contact with underground water flowing from the mountain side, generating radioactively contaminated water every day. In order to dismantle the reactor, it is necessary to take out the melted fuel, but high radiation levels inside the reactor had hampered work to locate the melted debris.
More than 80 percent of the radioactivity from the damaged reactors ended up in the Pacific — far more than reached the ocean from Chernobyl or Three Mile Island. Of this, a small fraction is currently on the seafloor — the rest was swept up by the Kuroshio current, a western Pacific version of the Gulf Stream, and carried out to sea where it mixed with (and was diluted by) the vast volume of the North Pacific.
U.S. Secretary of Commerce Penny Pritzker today determined there are commercial fishery failures for nine salmon and crab fisheries in Alaska, California and Washington.
In recent years, each of these fisheries experienced sudden and unexpected large decreases in fish stock biomass or loss of access due to unusual ocean and climate conditions. This decision enables fishing communities to seek disaster relief assistance from Congress.
In 2016, the pink salmon harvests in Kodiak, Prince William Sounds, Chignik and lower Cook Inlet came in woefully under forecast and stumped biologists as to why.
The estimated value of Kodiak’s 2016 haul was $2.21 million, compared to a five-year average of $14.64 million, and in Prince William Sound the ex-vessel value was $6.6 million, far less that the $44 million five-year average. The total state harvest was the smallest since the late 1970s.
Although state biologists weren’t ready to declare a cause for the poor pink salmon performance, the Commerce Department press release attributed the disasters to “unusual ocean and climate conditions.”
Internal radiation, on the other hand, emanates from radioactive elements which enter the body by inhalation, ingestion, or skin absorption. Hazardous radionuclides such as iodine-131, caesium 137, and other isotopes currently being released in the sea and air around Fukushima bio-concentrate at each step of various food chains (for example into algae, crustaceans, small fish, bigger fish, then humans; or soil, grass, cow’s meat and milk, then humans). After they enter the body, these elements – called internal emitters – migrate to specific organs such as the thyroid, liver, bone, and brain, where they continuously irradiate small volumes of cells with high doses of alpha, beta and/or gamma radiation, and over many years, can induce uncontrolled cell replication – that is, cancer. Further, many of the nuclides remain radioactive in the environment for generations, and ultimately will cause increased incidences of cancer and genetic diseases over time.
Decommissioning the reactors will cost 8 trillion yen ($70.4 billion), according to an estimate in December from the Ministry of Economy, Trade and Industry. Removing the fuel is one of the most important steps in a cleanup that may take as long as 40 years.
The unprecedented nature of the Fukushima disaster means that Tepco is pinning its efforts on technology not yet invented to get the melted fuel out of the reactors.
The company aims to decide on a fuel removal procedure for the first reactor during the fiscal year ending March 2019, and to begin removing fuel in 2021.