Chernobyl Accident

(This blog is replacing the Pandora’s Promise blog that I could not access the video for.)

In April 1986, a result of a flawed Soviet reactor design combined with ineffectively trained personnel responsible for operation and the lack of any safety culture, caused the Chernobyl accident in Ukraine. On the 25^th of April the personnel at Chernobyl 4 reactor started preparing for a test to determine how long turbines would spin and supply power to the main circulating pumps. This test was conducted a year prior but was unsuccessful due to the power from the turbine rapidly was depleted.

There were a series of operation steps that took place, which put the reactor in an extremely unstable condition. The planned procedure included shutting off the reactor’s emergency core cooling system that was responsible for supplying water for cooling the core in an emergency. As the process continued, the power at which the reactor was operating was less then the minimum operating reactivity margin, which is a violation. The operator made a poor decision and the process was continued. At this point, any efforts that could have been made to increase the power were disturbed by xenon poisoning, reduced coolant void, and graphite cool down.

The power excursion rate emergency protection system signals came on when power started to rise and exceeded the required level. This caused fuel elements to rupture that led to increased steam generation, which then further increased the power level. There was a rupture of several fuel channels that increased the pressure inside of the reactor that caused the reactor support plate to become detached and jammed the control rods. While the channel pipes were rupturing, more steam had been generated as a result of the lack of pressure of the reactor cooling circuit.

At this point there were two explosions. The first one was the initial steam explosion and second was a result of the build-up of hydrogen due to steam reactions. As stated by the World-Nuclear Organization, “Fuel, moderator, and structural materials were ejected, starting a number of fires, and the destroyed core was exposed to the atmosphere. One worker, whose body was never recovered, was killed in the explosions, and a second worker died in hospital a few hours later as a result of injuries received in the explosions.”

There was a massive immediate impact to the environment after the accident. At the time, this accident was named as the largest uncontrolled radioactive released into the environment for any civilian operation. For about 10 days, large amounts of radioactive substances were released into the air, which caused a social and economic disruption in Ukraine.

With the task of cleaning up the radioactivity of the site, about 200,000 people were recruited from the Soviet Union. These people received high doses of radiation, and later about 400,000 more people were called in to help and received lower does of radiation. About 116,000 residents were evacuated and later about 1,000 relocated back to the area unofficially.

Human health has been affected by the Chernobyl accident. Whether people were exposed to radiation directly fro the radioactive cloud or the radioactive materials deposited on the ground and were consumed through contaminated food there was a high level of contamination. Children’s thyroids were heavily exposed to radioactive iodine, which caused serious health concerns. 28 emergency workers died from acute radiation syndrome, 15 patients died from thyroid cancer, and it is estimated that 4,000 died from cancers caused by Chernobyl.

The main lesson learned from the Chernobyl accident is reactor safety. There have been modifications made in reactors currently operating. Following Chernobyl, the International Atomic Energy Agency brought together engineers to focus on safety improvements. According to the Chernobyl Forum report, about seven million people received or are eligible for benefits as “Chernobyl victims.”

Works Cited

"Chernobyl Nuclear Accident." Scientific Facts on  the. N.p., n.d. Web. 30 Oct. 2013. <http://www.greenfacts.org/en/chernobyl/index.htm>.

"Chernobyl fuel transfer milestone." Chernobyl. N.p., n.d. Web. 30 Oct. 2013. <http://www.world-nuclear.org/info/Safety-and-Security/Safety-of-Plants/Chernobyl-Accident/#.UnE3HRaRPFJ>.

"History of Chernobyl Disaster." ICRIN > Home >. N.p., n.d. Web. 30 Oct. 2013. <http://www.chernobyl.info/Default.aspx?tabid=274>.

MIT Nuclear Reactor Laboratory Trip

       

The MIT Nuclear Laboratory (MIT-NRL) is the second largest university research reactor in the United States and the only university research facility in the United States where students have the ability to get hands on experience with the development and implementation of nuclear engineering experimental programs. The MIT-NRL is responsible for educational training and cutting-edge research of nuclear fission engineering, material science, radiation effects in biology and medicine, neutron physics, geochemistry, and environmental studies. The NRL has been operating 24 hours a day, 7 days a week since 1958 and has been upgraded in 1975 and makes minor upgrades as needed.

During our trip to the MIT-NRL on October 18, 2013, we started by listening to a presentation made one of the directors of operations of the laboratory. During the presentation, we were briefed on the history of MIT and the reactor, the responsibilities of the employees and the reactor, and the processes that occur in the reactor.

Before we were allowed to enter the MIT-NRL we were all assigned a dosimeter that is about the size of a pen and attached them to our clothing. This meter allowed us to know how much exposure we experienced. This was intimidating due to the fact that I had the slightest idea of what I was going to walk into.

Unlike other nuclear reactors, the MIT Research Reactor does not produce electricity and is primarily responsible for the production of neutrons therefore the director of operations explained the fission process to us using a diagram (similar to the one shown below). The power level of the reactor is 6 MW, which is much smaller compared to 3000 MW for a large electric power reactor.

The NRL has contributed valuable information to many research projects during the years of operation such as closed-loop digital control of spacecraft and terrestrial reactors; boron neutron capture therapy for the treatment of cancer; material studies for the next generation of reactors; neutron activation analysis used for the study of autism; and the investigation of nanofluids for nuclear applications.

During our tour we were able to visit the medical room where the boron neutron capture therapy for the treatment of cancer took place. Our tour guide explained that doctors would use a beam to send boron into the brain to attack and destroy malicious tumors. This experiment had successful variables to it as well as unsuccessful as the doctors struggled with managing the speed of the neutrons.

An interesting piece of information that I took away from this tour was that we get more radiation in an airplane during a flight from New York City to LA than the radiation you would encounter while inside of the reactor.

My after thoughts of the MIT-NRL brought me to the Fukushima reactor, and I initially feared that this reactor could wipe out Boston similar to the disaster in Japan. Although with research, lessons learned from Fukushima have been incorporated in new safety features in nuclear reactors in several countries. The MIT-NRL has also been operating safely for over 50 years and due to the small size and low power level, it poses a much smaller threat than other reactors.

MIT Nuclear Reactor Laboratory: Home. N.p., n.d. Web. 27 Oct. 2013. <http://web.mit.edu/nrl/www/index.html>.

The Robert Stirling Invention

In 1816 Robert Stirling invented an engine that is much different than the engine in your car. The Stirling engine has the potential to be much more efficient than gasoline or diesel engines, although today it is primarily used in specialized items that focus on quiet operation such as a submarine.

What makes this engine different than the internal-combustion engines in cars is that it utilizes the Stirling cycle. During the Stirling cycle process, gasses never leave the engine, as there are no exhaust valves and results in a very quiet engine. The Stirling cycle uses an external heat source such as gasoline, solar energy, or even the heat produced by the combustion of decaying plants.

To explain how the Stirling cycle works, there is an important key principle. A fixed amount of gas is sealed inside the engine and the cycle involves changing the pressure of this gas inside the gas. A fixed amount of gas in a fixed amount of space combined with a rising temperature, pressure will increase while the opposite with cause the pressure to decrease.

Stirling engines have a sealed cylinder with one part that is hot and one that is cold. The working gas contained inside of the engine is moved from the hot side to the cold side by a mechanism. When the gas is on the hot side, it expands and pushes a piston then it moves back to the cold side and contracts. There are different types of Stirling engines and the more common types are the two-piston type Stirling engine and the displacer type Stirling engine.

The displacer type Stirling Engine is continuously heated by a heat source on the space below the displacer piston while the space above the displacer piston is continuously cooled. Below is an animation to explain this type.

The two-piston type animation is shown below demonstrating the space above the hot piston is continuously heated by a heat source while the space above the cold piston is continuously cooled.

Stirling engines are not more common because of the impracticality of use in most items. With the heat source being external, the engine encounters some delays when responding to changes in the amount of heat being applied, which caused the engine to require some time to warm up before it can produce power and the engine is not capable of changing the amount of power output quickly.

Works Cited

"American Stirling Company." American Stirling Company. N.p., n.d. Web. 27 Oct. 2013. <http://www.stirlingengine.com>.

"How Stirling Engines Work." HowStuffWorks. N.p., n.d. Web. 27 Oct. 2013. <http://auto.howstuffworks.com/stirling-engine1.htm>.

"Stirling Engine Home Page -English-." Stirling Engine Home Page -English-. N.p., n.d. Web. 27 Oct. 2013. <http://www.bekkoame.ne.jp/~khirata/indexe.htm>.

"Stirling Engine Society USA." Stirling Engine Society USA. N.p., n.d. Web. 27 Oct. 2013

            <http://www.sesusa.org>.

Fukushima Nuclear Power Plant Disaster

On March 11, 2011, at Fukushima Daiichi in Japan, there was the most extensive release of radioactivity disaster since the Chernobyl accident in 1986 and the Three Mile Island accident in 1979. An earthquake and tsunami struck Fukushima Daiichi nuclear power station, which caused the backup power systems that were used to cool off reactors in the plant to be knocked out. Three of the reactors experienced fuel melting, hydrogen explosions, and radioactive releases.

On March 12, 2011, radioactive contamination from the plant had not cause any immediate deaths but did force the evacuation of communities up to 20km surrounding the plant affecting ten of thousands of residents. The Japan government later announces that the evacuation zone to be expanded causing 160,000 people to evacuate.

The Fukushima nuclear power complex consists of six nuclear boiling water reactor units operated by Tokyo Electric Power Company. When the earthquake struck, units 1, 2, and 3 that were generating electricity, shut down. Offsite power supplies and backup diesel generators were lost. The tsunami following the earthquake caused flooding which caused units 1, 2, 3, and 4 to be lost. At the time, unit 4 was undergoing a maintenance shutdown in which all of the nuclear fuel had been relocated to the unit’s spent fuel storage pool. Units 5 and 6 continued to stay cool and operate with the power from one generator. With the lack of AC power in the units, heat and pressure built up, fuel rods in the reactor cores overheated, a reaction between hydrogen and steam escaped and exploded. This explosion interfered with any possible efforts made by plant workers to restore cooling and radioactivity began to spread.

The radioactive material was released into the air producing a high amount of radiation near the plant and left the surrounding areas uninhabitable, and contaminated water from the plant was discharged into the sea, which created an international dispute.

Assistance was provided to Japan to deal with the disaster from the United States and other countries and the International Atomic Energy Agency.

In September 2012, Japan announced that it plans to abandon nuclear power by year 2030 and not begin any new construction on nuclear reactors during that time.

The nuclear disaster of Fukushima has initiated a revision of nuclear plant safety requirements around the world.

Now, two and a half years later, Japan’s efforts to clean up the remains from the Fukushima Daiichi power plant is some what of another disaster waiting to happen. Tokyo Electric Power Co. was put in charge of the cleanup process from the disaster and now the plant site is storing 90 million gallons of radioactive water while an additional 400 tons of toxic water is flowing daily into the ocean.

Below is an animated from the Washington Post that does a great job demonstrating the disaster and the cleanup plan of the plant that could take four decades to accomplish.

http://apps.washingtonpost.com/g/page/world/preventing-radioactive-leaks-at-fukushima-daiichi/511/

Works Cited

"Fukushima nuclear crisis timeline." Greenpeace. N.p., n.d. Web. 26 Oct. 2013. <http://www.greenpeace.org/international/Global/international/publications/nuclear/2012/Fukushima/Fact%20Sheets/Fukushima_Timeline.pdf>.

Harlan, Chico. "For Tepco and Japan’s Fukushima Daiichi nuclear plant, toxic water stymies cleanup." Washington Post. The Washington Post, 22 Oct. 2013. Web. 26 Oct. 2013. <http://www.washingtonpost.com/world/for-tepco-and-japans-fukushima-daiichi-nuclear-plant-toxic-water-stymies-cleanup/2013/10/21/406f4d78-2cba-11e3-b141-298f46539716_story.html>.

Holt, Mark, Richard Campbell, and Mary Beth Nikitin. "Fukushima Nuclear Disaster." Congressional Research Service I (2012): n. pag. FAS. Web. 26 Oct. 2013.

Solar Energy Efforts

Solar power is considered one of the cleanest and most abundant renewable energy sources available which is why solar technology is becoming a more popular idea to incorporate into new buildings and projects. While researching this topic, I came across a resources with a number of different solar projects that interested me and below, I have selected four to discuss how solar energy efforts are made around the world.

The Solar Ark in the geographical center of Japan is an ark-shaped photovoltaic power generation facility with over 5,000 panels that produce about 530,000 kilowatt-hours on a annual basis. This ark was designed to symbolize producing clean energy and was constructed by Sanyo Electric Company and completed in December 2001. Using cutting edge solar technology was a must for this project, which involved using crystal silicon and thin-film amorphous silicon with a 14-15% efficiency rate. Since the Solar Ark was constructed, data has been collected regarding the power-generating performance of the photovoltaic system.

Located in Dezhou, China resides the world’s largest solar-powered building. This building is a 75,000 square meter structure which features exhibition centers, scientific research facilities, meeting and training facilities, and a hotel all run on solar power gathered from the hundreds of solar panels located on the roof of this building. The sundial was an inspiration for this design in addition to the need to remind everyone of the urgent need to seek renewable energy sources.

Coming to the Arizona desert in 2015 is a large-scale solar energy project that entails building a full-scale solar tower. This tower is 800+ meters (2625 ft.) tall with 200-megawatt power generation capacity predicted to produce enough power for 150,000 US homes. How this giant tower is going to work is a simple idea that the sun will beat down on the large covered greenhouse area at the bottom, while warming up the air underneath it. The hot air produced will then want to rise so the center point will lead to tower in the middle with a lot of turbines at the base of this tower that will generate electricity from that natural updraft. This project is estimated to cost around $750 million to build and will run at an efficiency of about 60%, which is much more efficient and reliable than other renewable energy sources.

The Sahara Forest Project aims to “bring green to the desert”.  The goal is to create re-vegetation and green jobs through the production of food, water, clean electricity and biomass in desert areas. This project will implement materials that we have in abundance including CO2, salt water, sunlight, and desert areas and combining them with already existing and proven technologies. This project is projected to begin in 2015 and if successful, this will provide great benefits for our environment. For further reading on the Sahara Forest Project, this website provides interesting insights and valuable information, (http://saharaforestproject.com). 

As far as the wisdom of clean energy subsides goes, I found an article from The New York Times that questioned if this was the end of clean energy subsides. It stated that, “The federal government has given generously to the clean energy industry over the last few years, funneling billions of dollars in grants, loans and tax breaks to renewable power sources like wind and solar, biofuels and electric vehicles. “Clean tech” has been good in return”. Although it seems that the relationship between the progress in clean energy and the government is productive, the clean energy incentives that were provided by President Obama in 2009 are coming to an end. Funding for clean energy will be seeing a 75% decline over the next few years. It is debated if any real success in the clean energy sector would have been made without help from the government.

Works Cited

Blain, Loz. "Twice the height of the Empire State - EnviroMission plans massive solar tower for Arizona." Gizmag | New and Emerging Technology News. N.p., n.d. Web. 7 Oct. 2013. <http://www.gizmag.com/enviromission-solar-tower-arizona-clean-energy-renewable/19287/>.

"Home - Sahara Forest Project." Home - Sahara Forest Project. N.p., n.d. Web. 7 Oct. 2013. <http://saharaforestproject.com>.

Nusca, Andrew. "World’s largest solar-powered office building opens in China | SmartPlanet." SmartPlanet - Innovative Ideas That Impact Your World. N.p., n.d. Web. 7 Oct. 2013. <http://www.smartplanet.com/blog/smart-takes/worlds-largest-solar-powered-office-building-opens-in-china/2798>.

"SOLAR ARK | SANYO Electric Co., Ltd. | Panasonic." Panasonic Global Home. N.p., n.d. Web. 7 Oct. 2013. <http://panasonic.net/sanyo/solarark/en/index.html>.

"The End of Clean Energy Subsidies? - NYTimes.com." The New York Times - Breaking News, World News & Multimedia. N.p., n.d. Web. 7 Oct. 2013. <http://www.nytimes.com/2012/05/06/opinion/sunday/the-end-of-clean-energy-subsidies.html?_r=0>.

"The World’s 6 Coolest Solar Powered Projects top 6 solar projects around the world - Gallery Page 1 – Inhabitat - Sustainable Design Innovation, Eco Architecture, Green Building." Inhabitat | Design For a Better World!. N.p., n.d. Web. 7 Oct. 2013. <http://inhabitat.com/the-worlds-6-coolest-solar-powered-projects/solar-projects/>.