Fukushima accident, the Chernobyl of our time

Browns_Ferry 

On March 11th, 14:46 JST, a strong earthquake with the magnitude of 9.0, dubbed “The 2011 off the Pacific cost of Tohoku Earthquake” by the Japan Meteorological Agency (JMA), occurred 130 km ESE off Ojika Peninsula. The Tohoku quake caused a Tsunami with waves of up to 15 meters, and damaged the Fukushima Daiichi Nuclear Power Plant compound, causing the failure of the generator cooling system. Due to reactor nuclear meltdown, as of April 12th, Tepco declared the INES rating at Fukushima Daiichi NPS to be Level 7, equaling it to the Chernobyl accident with 90% less radiation leakage compared to the Chernobyl accident. The estimated number of casualties caused by the earthquake and tsunami on April 11th was at 12,000 deaths and 15,000 missing persons. (Asia, 2011, April 11th)

A complete comprehensive and unbiased report on what happened with the Fukushima nuclear power plant, the radiation levels in Japan and the global consequences of these accounts is a necessity! Unfortunately, many lives were lost. This fact cannot and should not be belittled in any way, which makes it even more important to set the story straight; no assumptions, just facts.

Naturally, after a monthly mixture of all levels of reporting, from popular to scientific, the overview seems colorful to say the least. But facts remain and should prevail. We’ve tried to sum them up for anyone who would like to know the facts about the Fukushima accident.

 

 

 

BASICS

Earthquakes

500,000 Earthquakes occur per year, 100,000 of those can be felt. The United States Geological Survey estimates that there have been an average of 18 major Earthquakes per year (magnitude 7.0-7.9) and one great earthquake (magnitude 8.0 or greater) per year.

The strongest earthquake recorded on a seismograph reached 9.5 magnitude and occurred on 22 May 1960 in Canete, Chile. (USGS, Measuring the size of an Earthquake) (USGS, earthquake hazard program)

Tsunamis

Compared to wind waves which have a wavelength of approximately 100m, tsunamis can have wavelengths of up to 200 km (120 miles). Such waves can travel up to 800 km/h (500 miles/hour). As the waves hit the shore their speeds decrease to 80 km/h, due to the shallower waters. (NTHMP) About 80% of Tsunamis occur in the Pacific Ocean. Highest recorded tsunami wave occurred in Spirit lake in Washington USA due to a magma eruption, it reached heights of 260 meters. (Two, 2000)

Why we use Nuclear power plants

Power systems are comprised of power plants and their task is to supply and match the electric energy demands of our societies. Energy demands vary on a minute-to-minute basis as factories, air conditioners and TV’s are turned on or off. The goal of the power systems is to match the demands as closely as possible, without depriving the energy users at any moment. Our industry and society require three types of energy based on their availability:

  • Constantly supplied energy which is always available and powers factories, hospitals, data centers.
  • daily supplied energy that can be turned on or off in a matter of hours and
  • on-demand peak energy which can be turned on or off immediately

Consequentially, our power systems must offer all types of energy listed above at all times, and they do so by combining the energy from various types of power plants. The important fact we need to know is, that the only power plants that can constantly supply electric energy are nuclear, coal or gas-powered. Another important fact is also that 1kg of Uranium-235 (U235) produces approximately 3 million times more energy than 1 kg of coal.

Basic Boiling water reactor nuclear power plant operation explanation

Operating cycle

Fukushima Nuclear power plant compound consists of Fukushima I and Fukushima II power plants, which are comprised of 10 boiling water reactors or BWR’s. The principal of operation for BWR nuclear reactors is based on nuclear fission: uranium dioxide or MOX fuel absorbs a neutron and it splits into two or more lighter nuclei, releasing kinetic energy, gamma radiation and free neutrons. These are also referred to as fission products. Neutrons that were produced during fission are then absorbed by other fissile atoms, continuing the fission.

Nuclear reactors basically harness the thermal energy released from nuclear fission to produce electrical energy. The heat resulting from the fission boils the water, water turns into steam, is guided towards turbines which it propels, the turbines then drive the generators to produce mechanical energy and finally the generators produce electricity. The steam which passed through the reactor-turbine cycle is directed through condensers which cool it down and turn it back to water.

Radiation

Radiation is a form of energy. When radioactive materials, such as Uranium, are disintegrating, they produce daughter products and neutrons. These daughter products split into smaller particles and emit Gamma rays, Beta particles or Alpha particles and neutrons that are consequently produced continue to be absorbed by remaining atoms. Radiation transfers energy into living organisms and damages them. Gamma rays are absorbed by breathing and cannot be stopped by metals as they can pierce them or pass through them. Beta and Alpha particles however, can only cause damage to us if they are inside our bodies and can’t pass through protective clothing and filters. Iodine, Cezium and Stroncium are examples of Beta particles. Iodine causes damage in thyroid, Cezium in muscle tissue and Stroncium in bone marrow. Alpha particles, which come from depleted Uranium and Plutonium, can also be breathed into the body and cause cancers on lungs.

The way radiation is measured is in Becquerels, Sieverts and half-life. 1 disintegration per second equals 1 Becquerel. 1 Millisievert (mSv) equals 100 Millirem, this is used to describe personal exposure and damage to living tissue. Iodine has a half-life of 8 days, which means in 8 days half of it is gone. Cezium has a 30 year half-life, meaning that it will take 300 years to disappear. Plutonium has a half-life of 2400 years and if leaked it would stay in the environment for up to 250,000 years. 1 dollar bill weighs 1 gram. If you cut it into a million pieces you get 1 microgram. 1 microgram of Plutonium can cause deadly cancer.

What went wrong at Fukushima

In a nutshell

At 2:46 PM on Mar11 2011 units 1, 2 and 3 were shut down due to the Miyagiken-oki Earthquake, units 4,5 and 6 were not operational due to planned maintenance. Off-site power systems malfunctioned and emergency diesel generators were started up to cool the reactors. Following the subsequent tsunami with waves of up to 15 meters in height at the Fukushima Nuclear power plant caused the emergency shut-down of diesel generators at 3:41 due to a malfunction. At 3:42 PM INES Level 1 emergency was declared. There was a partial nuclear meltdown at units 1, 2 and 3 rated at level 7 on the INES scale and an uncovering of spent fuel rods at unit 4, rated at Level 3 on the INES scale. (TEPCO, 2011)

On April 15th 2011 radiation levels have reached one tenth of radiation levels recorded after the Chernobyl accident. Highest radiation levels on Apr 15th 2011 were recorded at the south side of the office building – 530 µSv/h. There is highly radioactive contaminated water accumulated on the basement of Unit 2 turbine building and in the concrete piping outside the building. Samples from seawater surrounding the Fukushima Daiichi NPS contain 2500-times more I-131 than the legal limit. (Japan Industrial Forum, 2011) Traces of Plutonium have been found on at least five locations 30 km from the Fukushima plant, highly contaminated water is being released into the sea daily. (Gundersen, Fukushima Updates, 2011)

According to the IAEA (International atomic energy agency), the background radiation has spread over the 30 kilometers area well into the 40 kilometers area around the Fukushima Nuclear Power station and it amounts to more than 1600-times the normal background radiation level. IAEA reports on April 15th that the highest levels of background gamma-beta radiation were found less than 23 km from the plant in amounts of up to 2.5 MBq/m2. The source of the background radiation are the noble gas clouds hovering over the mentioned area, comprised of Xenon and Kripton, which do not react with anything but emit Gamma rays. This means 2,500,000 disintegrations (decay of radioactive products which emits Gamma rays, beta particles or Alpha particles) of radioactive materials per second in the ground 29 kilometers from the Fukushima power plant. This also means that the evacuation radius should be much larger than proposed at the moment as radiation of 2.5 MBq/m2 is well above the allowed limit. For comparison, in Chernobyl the evacuation radiation limit was 0,5 MBq/m2.

Influence to the people’s life.

Radioactive material was detected from milk and agricultural products from Fukushima and neighboring prefectures. The government issued order to limit shipment and intake for some products. Radioactive iodine, exceeding the provisional legal limit, was detected from tap water sampled in some prefectures. Small fish caught off the coast of Ibaraki on Apr.4th have been found to contain radioactive cesium and iodine above the legal limit. Small amount of Strontium was detected from some samples of soil and plants taken in the atea that is 2080 km far from the power station. (Japan Industrial Forum, 2011)

Conclusion

Fukushima NPS compound was simply not designed to meet the combined security criteria of the Earthquake stronger than magnitude 8.5. According to USGS, the strongest conceivable Earthquake that could occur, could reach the magnitude of 10.5. Earthquakes have been recorded for the last 100 years and the strongest recorded Earthquake took place in Chile and was rated at 9.5. (USGS, earthquake hazard program)

Our civilization can’t deal with present energy demands without Nuclear power plants for which we need better construction, control and contingency management. On the contrary, with exponentially rising energy demands and lagging energy production, we are faced with inevitable energy crisis. Without a doubt, it is easier to lower energy consumption than increase production. With upgrades of our power systems to smart-grids and inclusion of battery technologies into transportation systems and power management systems, we are closer to the possibilities of including more renewable energy sources, but the demand for a large portion of uninterrupted base energy sources will remain.

That being said, when a Nuclear power plant needs to be built on an area prone to earthquakes, the buildings should be designed to withstand natural disasters stronger than any natural disasters previously recorded. Buildings should therefore be strong enough to withstand earthquakes of magnitudes up to 10.5, and biggest Tsunami waves. However, it is a question if buildings like that are even possible to construct.

As mentioned in the previous chapter, design of Nuclear power plants should incorporate mitigation of scenarios with up to 100% fuel damage and complete loss of containment, leakage of pools, loss of water cooling systems and backup pressure decrease systems etc.

In 60 years there have been 19 Nuclear power plant accidents either involving more than US$100 million in property damage or multiple fatalities. Only two of these accidents (Chernobyl and Fukushima) have been rated as level 7 incidents on the International Nuclear Emergency scale.

Although present radiation readings appear to be lower than those of the Chernobyl incident, the full extent of the Fukushima Nuclear power plant meltdown is still to be determined. There will undoubtedly be a wide geographical, if not a global, effect and consequences. We are witnessing one of the greatest and most devastating tragedies of our time and should act accordingly.

If you can afford it, donate to the victims closest to the accident. You can do so by visiting this link: http://www.google.com/crisisresponse/japanquake2011.html

Useful links:

Sources

  • Asia, S. (2011, April 11th). Damage Needs/assessment in the affected area of the 2011 off the Pacifik Coast of Tohoku Earthquake and Tsunami. OYO International Corporation and Kyoto University.
  • Gundersen, A. (2011, April 13). Fukushima Updates. Retrieved April 13, 2011, from fairewinds.com: http://www.fairewinds.com/updates
  • Japan Industrial Forum, I. (2011). Information on Status of Nuclear Power Plants in Fukushima. Fukushima: JAIF.
  • Milosevic, V. (2011). The Fukushima Daiichi Nuclear Power Station incident following the Tohoku earthquake and Tsunami (1st ed.). Ljubljana, Slovenija.
  • NTHMP. (n.d.). Tsunami Terminology. Retrieved April 13th, 2011, from NTHMP history 1995-2005: http://nthmp-history.pmel.noaa.gov/terms.html
  • TEPCO. (2011, April). Fukushima Daiichi. Retrieved Mar-Apr 2011, from Tokyo Electric Power Company: http://www.tepco.co.jp/en/nu/press/f1-np/index-e.html
  • Two, B. (Director). (2000). Mega-Tsunami: Wave of destruction [Motion Picture].
  • USGS. (n.d.). earthquake hazard program. Retrieved April 13, 2011, from earthquake USGS: http://earthquake.usgs.gov/learn/faq/
  • USGS. (n.d.). Measuring the size of an Earthquake. Retrieved April 13, 2011, from earthquake USGS: http://earthquake.usgs.gov/learn/topics/measure.php