Ed Lyman of the Union of Concerned Scientists will be a member of a Nuclear Regulatory Commission panel discussing the storage of spent nuclear fuel rods at a meeting on January 6, 2014. allthingsnuclear.org
Blog
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Geiger Readings for January 4, 2013
Ambient office = 83 nanosieverts per hourAmbient outside = 83 nanosieverts per hourSoil exposed to rain water = 95 nanosieverts per hourBanana from Top Foods = 114 nanosieverts per hourTap water = 78 nanosieverts per hourFiltered water = 63 nanosieverts per hourAlaskan Copper River Salmon = 82 63 nanosieverts per hour -
Geiger Readings for January 4, 2013
Ambient office = 83 nanosieverts per hourAmbient outside = 83 nanosieverts per hourSoil exposed to rain water = 95 nanosieverts per hourBanana from Top Foods = 114 nanosieverts per hourTap water = 78 nanosieverts per hourFiltered water = 63 nanosieverts per hourAlaskan Copper River Salmon = 82 63 nanosieverts per hour -
Nuclear Fusion 2 – Discovery of Fusion
In 1929, Robert Atkinson of Rutgers University in the U.S. and Friedrich Houtermans of the Georg-August University of Gottingen in Germany were working on a theory of nuclear fusion as the basis for stellar energy production. They applied George Gamow’s theory of quantum tunneling and Albert Einstein’s famous equation E = MC2 to combining or fusing nuclei of light elements to form heavier elements. Their work showed that such a process could release enormous energy that would explain the energy output of starts. Their theory was not accepted when it was first proposed because it required that stars be mostly hydrogen which was not believed to be the case at the time.
In 1932, Marcus Oliphant, an Australian scientist, was working at the Cavendish Laboratory of Cambridge University. He used their particle accelerator to fire nuclei of heavy hydrogen which contained a neutron in addition to a proton at targets of different elements. He discovered hydrogen 3 which contains two neutrons in the nucleus along with the proton and helium 3 which contained a single neutron in its nucleus along with the two protons. When helium 3 nuclei collided with hydrogen 3, the particles that were produced had much more energy than the two parent particles. He had demonstrated nuclear fusion in his laboratory.
In 1938, Hans Bethe, a German/American nuclear physicist at Cornell University in the U.S., attended a conference in stellar energy generation, a subject that he had not been interested in prior to the conference. George Gamow and Carl Friedrich von Weizacker had propose a simple fusion process for the energy generated by stars in a 1937 paper but it could not account for the observation of helium in stars. In their process, two hydrogen nuclei fused to become hydrogen 2. Bethe became interested in the problem and he came up with a much more complex process that involved the fusing of hydrogen 2, Helium 3, Helium 4, Beryllium 7, Lithium 7 and helium 4. This did explain the helium in stars but not the heavier elements observed in stars. Following the conference, Bethe continued to work on the problem and found what is referred to as the Carbon-oxygen-nitrogen cycle. In this process, carbon 12 fuses with a single hydrogen proton which is then followed by further fusion of nitrogen 14, carbon 13, oxygen 15, nitrogen 15 and protons which ultimately produces a carbon 12 nuclei and a helium 4 nuclei. Ultimately, Bethe won the Nobel Prize for his work.
In 1941, Enrico Fermi, an Italian physicist, was working on the project that resulted in the first nuclear reactor called the Chicago Pile-1 at the University of Chicago. He proposed the idea of using a fission bomb to initiate a fusion reaction in a mass of hydrogen to Edward Teller who was also working on the Manhattan Project to create the first nuclear fission bomb. Although he had proposed the idea, he eventually lobbied against the creation of a hydrogen bomb.
The Carbon-Nitrogen-Oxygen fusion cycles in stars:
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Radiation News Roundup January 3, 2013
A ceremony has been held to mark the start of construction of the Global Centre for Nuclear Energy Partnership (GCNEP) near Delhi, India. world-nuclear-news.org
More European Union money will go to decommission nuclear reactors in Bulgaria, Slovakia and Lithuania, but the bloc’s Council of Ministers has requested tighter project management. world-nuclear-news.org
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Geiger Readings for January 3, 2013
Ambient office = 103 nanosieverts per hourAmbient outside = 89 nanosieverts per hourSoil exposed to rain water =83 nanosieverts per hourRed seedless grapes from Top Foods =77 nanosieverts per hourTap water = 67 nanosieverts per hourFiltered water = 53 nanosieverts per hour -
Nuclear Fusion 1 – Introduction
I have focused on nuclear reactors that utilize nuclear fission to generate power because they have existed and functioned for decades. I have briefly covered some esoteric reactor types such as sodium cooled fast breeder reactors, thorium reactors and small modular reactors although they not proven technologies even after a great deal of research and development. Today I am going to begin a series of posts on the possibility of utilizing nuclear fusion reactors for power generation. My only mention of fusion in the past has been in the context of hydrogen bombs where a fission bomb is used to ignite a fusion reaction.
Nuclear fission occurs when a heavy unstable nucleus breaks apart, releasing energy and leaving behind nuclei of lighter elements which may or may not be radioactive. Nuclear fusion occurs when the nuclei of lighter elements fuse to form heavier elements, releasing energy in the process.
Our sun is powered by nuclear fusion. Hydrogen nuclei fuse to form helium nuclei. This process can continue up the periodic table until it hits iron. There is a mathematical model of fusion called the nuclear packing faction curve. It shows how much energy can be derived from a particular fusion reaction. Hydrogen to helium produces the most energy. with less and less energy as you get to heavier and heavier elements. Beyond the formation of iron, the heavier nuclei actually require energy to fuse instead of producing it. Stars form concentric spheres where heavier and heavier elements form in the core. When iron dominates, new processes take over that sometimes lead to collapse and violent novas. It is in such novas that elements heavier than iron are formed.
When scientists came to understand the nuclear fusion process going on in the sun, they realized that if they could harness fusion for power, it would be able to provide huge amounts of energy for human civilization. Initially, it was thought that the sun was just a glowing ball of gas compressed by gravity to the point where the fusion reaction was initiated. According to existing theories at the time, there would be no internal structure to the gas ball. Unfortunately for the effort to develop fusion for energy production, it turns out that the sun has a great deal of internal structure with a number of different processes happening simultaneously in different zones within sphere. When scientists tried to reproduce the fusion reaction by compressing hydrogen gas, instead of a uniform ball of gas, various sorts of transitory structures emerged which interfered with the fusion process and impeded their progress.
There is an old joke that fusion power is just forty years away but, like a rainbow, as time passes, it remains forty years away. A great deal has been learned about stellar dynamics and the process of nuclear fusion over the past few decades and progress has been made. Recently, for the first time, researchers were able to get more energy out of a fusion reaction than they had put in for very brief time. There is still far to go but a milestone has been passed. In coming posts, I will deal with the physics of, the history of and the prospects for safe and economical generation of electricity via nuclear fusion.
Internal structure of our sun:
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Radiation News Roundup January 2, 2013
In his photography, Michael Rothbart explore the human consequences of environmental contamination at Chernobyl and Fukushima. motherjones.com
Gizmodo’s claim that Fukushima could be in the middle of another meltdown is an unsubstantiated rumor. enenews.com
Texas has been hiding information about the level of radioactivity in drinking water. youtube.com
China’s new Yangjiang nuclear plant connected to the grid Tuesday, state media reported. nuclearstreet.com
