Tag Archives: Fukushima disaster

Fukushima in 2018: Radioactive Mud

Radioactive cesium from the crippled Fukushima No. 1 nuclear power plant continued to flow into Tokyo Bay for five years after the disaster unfolded in March 2011, according to a researcher.  Hideo Yamazaki, a former professor of environmental analysis at Kindai University, led the study on hazardous materials that spewed from the nuclear plant after it was hit by the Great East Japan Earthquake and tsunami on March 11, 2011.

Five months after disaster caused the triple meltdown at the plant, Yamazaki detected 20,100 becquerels of cesium per square meter in mud collected at the mouth of the Kyu-Edogawa river, which empties into Tokyo Bay.  In July 2016, the study team detected a maximum 104,000 becquerels of cesium per square meter from mud collected in the same area of the bay, Yamazaki said.

He said cesium released in the early stages of the Fukushima disaster remained on the ground upstream of the river, such as in Chiba Prefecture. The radioactive substances were eventually washed into the river and carried to Tokyo Bay, where they accumulated in the mud, he said.

On a per kilogram basis, the maximum level of radioactivity of cesium detected in mud that was dried in the July 2016 study was 350 becquerels.  The government says soil with 8,000 becquerels or lower of radioactive cesium per kilogram can be used in road construction and other purposes.  The amount of radioactive cesium in fish in Tokyo remains lower than 100 becquerels per kilogram, the national safety standard for consumption.

Excerpts from  NOBUTARO KAJI,  Cesium from Fukushima flowed to Tokyo Bay for 5 years, June 7, 2018

Radioactive Beaches: Fukushima at 2017

Kotohiki Beach, Japan. image from wikipedia

Six years after the Fukushima nuclear reactor disaster in Japan, radioactive material is leaching into the Pacific Ocean from an unexpected place. Some of the highest levels of radioactive cesium-137, a major by-product of nuclear power generation, are now found in the somewhat salty groundwater beneath sand beaches tens of kilometers away, a new study shows.

Scientists tested for radioactivity at eight different beaches within 100 kilometers of the plant, which experienced three reactor meltdowns when an earthquake and tsunami on March 11, 2011, knocked out its power. Oceans, rivers and fresh groundwater sources are typically monitored for radioactivity following a nuclear accident, but several years following the disaster, those weren’t the most contaminated water sources. Instead, brackish groundwater underneath the beaches has accumulated the second highest levels of the radioactive element (surpassed only by the groundwater directly beneath the reactor).

In the wake of the 2011 accident, seawater tainted with high levels of cesium-137 probably traveled along the coast and lapped against these beaches, proposes study coauthor Virginie Sanial, who did the work while at Woods Hole Oceanographic Institution in Massachusetts. Some cesium stuck to the sand and, over time, percolated down to the brackish groundwater beneath. Now, the radioactive material is steadily making its way back into the ocean. The groundwater is releasing the cesium into the coastal ocean at a rate that’s on par with the leakage of cesium into the ocean from the reactor site itself, Sanial’s team estimates.

Excerpts from Radioactive material from Fukushima disaster turns up in a surprising place, Science News, Oct. 2, 2017

See also Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan

Throwing Money at Nuclear Waste

Japan seeks final resting place for highly radioactive nuclear waste
…[W]ith a number of Japan’s nuclear reactors closed down for good in the wake of the Fukushima accident, the need for a permanent storage site is more pressing than ever.

The disaster, in which a 13-meter tsunami triggered by an off-shore earthquake crippled four reactors at the plant and caused massive amounts of radioactivity to escape into the atmosphere, also underlined just how seismically unstable the Japanese archipelago is and the need for the repository to be completely safe for 100,000 years.

“They have been trying to get this plan of the ground for years and one thing they tried was to offer money to any town or village that agreed to even undergo a survey to see if their location was suitable,” she said.  “There were a number of mayors who accepted the proposal because they wanted the money – even though they had no intention of ever agreeing to host the storage site – but the backlash from their constituents was fast and it was furious,” Smith added.  “In every case, those mayors reversed their decisions and the government has got nowhere,” she said. “But I fear that means that sooner or later they are just going to make a decision on a site and order the community to accept it.”

The security requirements of the facility will be exacting, the government has stated, and the site will need to be at least 300 meters beneath the surface in a part of the country that is not subject to seismic activity from active faults or volcanoes. It must also be safe from the effects of erosion and away from oil and coal fields. Another consideration is access and sites within 20 km of the coast are preferred.

The facility will need to be able to hold 25,000 canisters of vitrified high-level waste, while more waste will be produced as the nation’s nuclear reactors are slowly brought back online after being mothballed since 2011 for extensive assessments of their safety and ability to withstand a natural disaster on the same scale as the magnitude-9 earthquake that struck Fukushima.

When it is released, the government’s list is likely to include places in Tohoku and Hokkaido as among the most suitable sites, because both are relatively less populated than central areas of the country and are in need of revitalization efforts. Parts of Tohoku close to the Fukushima plant may eventually be chosen because they are still heavily contaminated with radiation from the accident.

Excerpts from Japan seeks final resting place for highly radioactive nuclear waste, Deutsche Welle, May 4, 2017

Cleaning Radioactive Water

tritium. Image from wikipedia

Russia’s nuclear energy giant Rosatom’s subsidiary RosRAO has created a prototype water decontamination plant for use at Tokyo Electric Power Co. Holdings’ Fukushima Daiichi nuclear power station — the site of Japan’s largest nuclear disaster in March 2011. The scrubbing facility, unveiled in June 2014, is capable of removing tritium, or radioactive hydrogen, from nuclear-tainted water, something beyond the capabilities of the Fukushima plant’s current cleanup equipment. Distillation and electrolysis isolate and concentrate the isotope, which is then locked away in titanium. Experiments under conditions similar to those on the ground reportedly show the technology cutting wastewater’s radioactive material content to one-6,000th the initial level, making it safe for human consumption or release into the ocean.

Duplicating the facility near the Fukushima site and running it for the five years necessary to process 800,000 cu. meters of contaminated water would cost around $700 million in all. Companies in Japan and the U.S. are at work on their own facilities for tritium disposal, but the Russian plan’s cost and technological capability make it fully competitive, according to the project’s chief.

Rosatom has made other overtures to Japan. Executives from a mining and chemical unit have visited several times this year for talks with Japanese nuclear companies, aiming to cooperate on decommissioning the Fukushima plant and upgrading a reprocessing plant in Aomori Prefecture for spent nuclear fuel. Russia has amassed a wealth of expertise dealing with damaged nuclear reactors in the wake of the Chernobyl disaster, and would like Japan to draw on that knowledge, the subsidiary’s chief executive said.

Revving up nuclear technology exports is essential to re-energizing Russia’s domestic industry and breaking free of dependence on the resource sector, Moscow has decided. The nuclear business, along with the space industry, is one of the few tech-intensive sectors where the country is internationally competitive. President Vladimir Putin has leaned more heavily on leaders in Europe and emerging countries in recent years to agree to deals with Russia’s nuclear companies.

In Japan, the public has grown wary of nuclear energy since the accident, leaving demand for new plants in the country at next to nil. Yet Japan has more than 10 reactors slated for decommissioning, creating a market worth up to 1 trillion yen ($9.42 billion) by some calculations. Russia aims to use cooperation on the Fukushima plant to crack the broader market and grow its influence, a source at a French nuclear energy company said…

But Japanese Prime Minister Shinzo Abe nevertheless visited Russia in May 2016 for top-level talks despite U.S. objections, eager to make progress on territorial disputes over islands north of Hokkaido. Preparation is underway for another summit in the far-eastern city of Vladivostok in September 2016, as well as a visit by Putin to Japan before the year is out.
Excerpts from TAKAYUKI TANAKA, Japan nuclear cleanup next target in Russian economic offensive, Nikkei Asian Review, July 24, 2016

Leaking Radioactive Water into the Ocean

Fukushima Waste not Tainted Anymore?

fukushima

The Chiba Municipal Government of Japan  on June 28, 2016  filed for Environment Ministry approval to lift the radioactive designation for waste stored in the city that was contaminated by the Fukushima reactor meltdowns five years ago.  This marked the first application in Japan seeking to lift the radioactive designation for waste tainted by the 2011 meltdowns at Tokyo Electric Power Company Holdings Inc.’s Fukushima No. 1 nuclear power plant.  The move came after the city found that levels of radioactive materials in the designated waste are lower than the national designation standards of over 8,000 becquerels per kilogram.

At present, designated radioactive waste generated by the nuclear disaster is stored in 12 prefectures in eastern Japan, including Tokyo.

In Chiba, 7.7 tons of designated waste is currently stored at a waste disposal center.The lifting of the designation will allow the city to dispose of the waste the same way as general waste,…

Excerpt from Chiba wants radioactive designation lifted from Fukushima-contaminated waste, The Japan Times, June 29, 2016

Fukushima Waste Disposal under the Ocean Floor

flatfish on ocean floor

The industry ministry will consider the feasibility of burying high-level radioactive waste from nuclear power plants under the seabed, which a working panel said Dec. 11, 2015 could be a “highly appropriate” solution.  In an interim report on disposal methods of highly contaminated materials from spent nuclear fuel, the panel said such waste could be disposed of in adjacent waters within 20 kilometers of the coastline.

It called the disposal method relatively realistic because the circulation of groundwater at sea is not as strong as on land. The panel said the site should be created in adjacent waters so that nuclear waste can easily be transported by ships.  The panel included the under-the-seabed disposal plan in nearby waters as a viable option for the final disposal site.

Based on this proposal, the ministry will set up an expert panel in January 2016 to discuss what specific technical challenges lay ahead.  The expert panel will discuss locations of active faults under the seabed and the impact of sea level changes to evaluate the feasibility of the project. It is expected to issue its recommendations by next summer.

While the government has encouraged municipalities to submit candidate sites for nuclear waste disposal, it is being forced to rethink this policy because no local government has come forward to provide a realistic disposal site.  Instead, it will hand-pick the “candidate sites from scientific perspectives” and unilaterally request local governments to comply with its research and inspection efforts.

Japan to consider ocean disposal of nuclear waste, THE ASAHI SHIMBUN, Dec. 12, 2015