Following the magnitude 9.0 earthquake and deadly tsunami nearly three weeks ago on March 11th, the Fukushima Daiichi nuclear energy facility along the northeastern coast of Japan has undergone at least three hydrogen explosions and continues to release radioactive steam and water. Precise measurements of the amount of released radioactive material are still unavailable, but measurements of nearby seawater on Thursday were almost 5,000 times above the regulatory limit.
This measurement of radioactive seawater is much higher than previous measurements. On Tuesday, the level was 3,355 times the legal limit. Three days before Tuesday, on March 26th, the level was 1,850 times the limit, according to Japan’s Nuclear and Industrial Safety Agency (NISA). As a result, the amount of radioactive material has exponentially increased in less than a week and this indicates a growing contamination area.
Three of the six reactors at the Fukushima nuclear facility remain unstable, according to a detailed release [.pdf] from NISA. Since Friday, March 25th, helicopters have poured water on each of these reactors, which is an attempt to lower the temperature of the core of each reactor and prevent another explosion.
Off-shore tankers are providing the helicopters with water, which is estimated to be about 200 tons of water each day (an olympic sized swimming pool holds 2,500 tons of water). A downside of pouring water onto the facility is the water becomes radioactive runoff, as well as the creation of radioactive steam, but engineers contend this “feed and bleed” method is better than allowing the temperatures of the reactor cores to rise and potentially explode.
On top of this infused water becoming radioactive, the facility itself is becoming extremely contaminated and increasing the danger for workers. These “suicide squads” consist of heroic workers who are being paid about $1,200 per day to build sandbag dams to prevent the spread of the radioactive runoff.
Additionally, plutonium, an extremely lethal isotope that can cause lung cancer with exposure to a single microgram, has been found in five different soil samples from around the facility, according to nuclear engineer Arnie Gundersen. Since plutonium is a particularly difficult isotope to detect, five separate identifications of plutonium is especially indicative of severe radioactive explosions.
With the release of radioactive materials, Japanese officials have ordered the evacuation of all residents within twelve miles of the Fukushima facility. Though, the United Nation’s International Atomic Energy Agency (IAEA) has recommended extending this evacuation area after detecting elevated radioactive levels in locations 24 miles from the Fukushima facility. The IAEA also collected 76 samples of various vegetables on March 28th and found 25 of these samples contained radioactivity.
Even though radioactive material has been confirmed in the air, food, and water, the radioactive levels remain below a dangerous level. Several countries are supporting Japan with the collection of data, including the US, France, Singapore, Russia, Ireland, & Switzerland, which have all confirmed very low detections of radioactivity in the air. The US Department of Energy recently conducted an aerial assessment of radioactive material around the Fukushima facility and generated the map below.
This map measures radioactivity in millirems per hour (mRems) and this unit indicates how much exposure to radioactivity a person absorbs each hour on the ground. A typical chest x-ray produces 10 mRem per image. The average American absorbs 620 mRem per year, according to the Nuclear Regulatory Commission.
As the map above shows, low but not insignificant radioactive levels are detected within the 25 miles surrounding the nuclear facility. The region northwest of the plant has received more radioactive material, potentially due to the wind. As a result, an individual standing five miles away from the Fukushima facility for five hours would absorb the same amount of radioactive material that is produced from a chest x-ray.
Meanwhile, even though the radioactivity of Japan’s atmosphere is not an immediate threat, the catastrophic implications of the earthquake and subsequent tsunami are growing. Monetary estimates of the damages are already over $300 billion, reflecting a momentous sum that will only exacerbate the already heightened debt of the Japanese economy. Moreover, the death toll of the disaster has already surpassed 12,000 and will likely continue to climb. With enormous challenges already on the table, the aversion of a nuclear meltdown at the Fukushima Daiichi nuclear facility is certainly imperative.
Update April 7th: The video below measures radiation in the ghostly evacuation zone. The unit of measure in the video is sieverts per hour. To give you an idea of a sievert, a chest x-ray emits 14 sieverts. At 1.5 km from the facility, this video measured 109 Sv/h. In other words, an individual absorbs the recommended annual amount of radiation every 22 hours.