Japan Radiation Map

Friday, February 14, 2014

The latest news from Japan's crippled Fukushima nuclear plant is not good.

Tokyo Electric Power Company has announced high levels of radioactive cesium have been recorded in the groundwater underneath Japan’s crippled Fukushima power plant. Contaminated groundwater samples were taken from a well outside. Tests have shown that the levels of cesium there are several thousand times higher than normal. Cesium-137 levels in the well water were at 54,000 becquerels per liter, while cesium-134 measured 22,000 becquerels, 220 times the permitted norm. The situation at the devastated nuclear power plant continues to deteriorate. According to TEPCO, the recent levels have soared to a record high. Experts are still trying to contain radioactive water that has been leaking. It has been discovered that the previous estimates were doctored to underplay the threat, with the plant operator shifting the blame on technical faults. Almost three years since the reactor meltdowns at the Fukushima Daiichi station, Tokyo Electric Power Co (Tepco) still lacks basic understanding of measuring and handling radiation, Nuclear Regulation Authority (NRA) Chairman Shunichi Tanaka said on Wednesday. The utility has been widely criticized for an inept response to the March 2011 disaster. Yet another Fukushima-related scandal has broken out as Japan's nuclear regulator criticized Tokyo Electric Power Co (Tepco)for incorrectly measuring radiation levels in contaminated groundwater at the site. Tepco said last week that groundwater drawn from a monitoring well last July contained 5 million Becquerel per liter of strontium-90, five times the reading of 900,000 Becquerel per liter recorded earlier in the well. Tepco said there was a calibration mistake with one machine measuring strontium levels of well water at the plant, and it had also found an error with devices that measure radiation. "Something like this cannot happen ... The data is what becomes the basis of various decisions, so they must do their utmost to avoid mistakes in measuring radiation," Tanaka told reporters, though he added the mistake did not pose a serious safety risk at the plant. A Tepco spokesman said the utility will re-check all radiation readings of groundwater in light of the record strontium levels. To put that number in perspective, the legal limit for releasing strontium 90 into the sea is 30 Becquerel per liter. Strontium-90 is a radioactive isotope produced by nuclear fission with a half-life of 28.8 years. Its can cause bone cancer, cancer of nearby tissues, and leukemia. Strontium-90 is probably the most dangerous component of the radioactive fallout from a nuclear weapon. The latest news from Japan's crippled Fukushima nuclear plant has sparked fresh concerns over uncontrolled radioactive pollution. A spike of beta radiation was detected near an ocean-facing well of Fukushima's No. 2 reactor from 2.4 million Becquerel per liter on Monday to 2.7 million Becquerel per liter on Thursday, the plant's operator, Tokyo Electric Power Company (TEPCO), announced on Friday. The radioactive materials were in a water sample taken from the observation well five meters from the coast, TEPCO said. The legal limit for strontium emissions is 30 Becquerel per liter. Half of the plant's reactors have experienced at least a partial meltdown since it was devastated by the March 2011 earthquake and tsunami. The water used to cool the reactors has been leaking into the soil and contaminating the ground water. Some of the radioactive water has been escaping into the Pacific Ocean. Last year, radiation leaks, power outages and other mishaps sparked international concern and prompted Japan's government to step in with more funds and support. As part of a turnaround plan approved by the government last month, Tepco hopes to re-start its biggest nuclear station, Kashiwazaki Kariwa, this summer. Tepco in November began the hazardous process of removing hundreds of brittle spent fuel rods from the damaged No. 4 reactor building at Fukushima. It said last week it had removed about 9 percent of more than 1,500 unused and spent fuel assemblies in the reactor's storage pool.

Friday, November 22, 2013

TEPCO begins critical work unloading Fukushima Daiichi Unit 4 spent fuel pool

On Monday at 15:18, TEPCO workers began work removing spent fuel from the crippled Fukushima Daiichi Unit 4 spent fuel pool, which holds 1,533 assemblies.  Of the 1,533 assemblies, 1,311 are spent fuel, the other 222 are unused.
This project has been labeled by some as one of the most dangerous nuclear operations in human history.  Experts all agree that the engineering challenges are on a scale unseen to date.
Workers are removing the unused assemblies first, as they do not emit as much radiation and heat as the spent fuel assemblies.
Each spent fuel assembly is made up of about 80 fuel rods, which by assembly can contain up to 7,500 trillion becquerels of radioactivity and around 1% plutonium by weight.
The 2013 World Nuclear Industry Status Report claims that the “full release from the Unit-4 spent fuel pool, without any containment or control, could cause by far the most serious radiological disaster to date.”
Work will be challenging, due to the amount of debris in the spent fuel pool from the March 2011 explosion, which ripped the building asunder.
Workers will discover new damage to fuel units they were unaware of previously.  The pieces of debris from the explosion were ejected with enough force to potentially damage fuel rods or jam multiple assemblies together.
The assemblies could also be moved too close together.  The spent fuel rods could break, or be exposed to air and potentially ignite; both scenarios would potentially release a massive amount of radiation, which could necessitate the evacuation of workers from the plant.
According to Bloomberg, if the rods were to overheat or break, a self-sustained nuclear chain reaction similar to the meltdowns in the crippled reactors could be prompted.
The spent fuel assemblies are gripped by a huge remote-controlled crane and transferred into dry cask storage containers which each can hold up to 22 assemblies.  Moving the first assembly into the cask took workers more than an hour.
Once the storage cask is full, workers will lift the container out, load it onto a trailer, and move it to the central repository.  Work is largely carried out at a slow crawl.   The movement of one cast out of the pool takes 12 hours over a 48-hour period, and 8 to 10 days to complete transfer to the new storage pool.
Tokyo Electric plans to finish removing all the spent fuel from the Unit 4 reactor building by the end of 2014.
Many experts have brought to light their concerns related to another major earthquake striking Japan near the Fukushima Daiichi site while workers are conducting removal work.
Source: TEPCO

Tuesday, March 29, 2011

Link to Japan Real-time radiation data.

Link to Japan Real-time data.

Some graphs are shown below. Three different sites show abnormal spikes at:
3/15/2011,  3/16/2011,  3/21/2011,  and 3/22/2011.

The map is updated every 10 minutes based on data from
Japan Nuclear Safety Division, Ministry of Education, Culture, Sports, Science and Technology (SPEEDI)

Tuesday, March 22, 2011

The intensifying nuclear crisis in Japan is raising anxieties on both sides of the Pacific over the potential impacts of radiation exposure, and a relative lack of official information on radiation has many worried. The nuclear radiation threat continues to spread in Japan after numerous explosions.