December 08, 2016

Carnival of Nuclear Energy 337

The Carnival of Nuclear Energy 337 is up at Neutron Bytes

MZ consulting - A new study by UNSCEAR shows that there is more radiation coming from coal plants than nuclear plants – and that workers mining the rare earths required for solar and wind are subject to higher doses than nuclear workers.

Report of the United Nations Scientific Committee on the Effects of Atomic Radiation (24 pages)

They calculated the collective doses to defined population groups resulting from one year’s global and regional electricity generation by each energy technology, integrated over specific time periods. The second metric consisted of the relevant collective doses divided by the amount of electricity generated by each technology. The reference year used for the comparisons was 2010.

The Committee estimated that the contribution from the coal cycle was more than half of the total collective dose to the local and regional public from the discharges due to a single year’s global electricity generation. That estimate was based on the assumption that the discharges originated from modern coal plants. The nuclear fuel cycle, on the other hand, contributed less than a fifth. The contribution from the coal cycle comes from discharges of natural radionuclides (primarily radon and its radioactive progeny) during coal mining, combustion of coal at power plants and coal ash deposits. Similarly, almost half of the exposures of the global public from the nuclear fuel cycle result from discharges of natural radionuclides during uranium mining and milling activities. These values depend on the share of each technology in total electricity production; in 2010 the coal cycle contributed about 40 per cent, the largest amount. Although radon and its progeny are relatively important contributors to the collective doses to the public for both the nuclear fuel cycle and the coal cycle, the associated individual doses are small compared with doses due to inhalation of radon and its progeny at levels that occur naturally in homes.

The Committee found, however, that the contribution of a given technology to the exposures of the global public was not simply a function of how much electricity that technology generated.

The Committee also assessed occupational exposures. The largest collective dose to workers per unit of electricity generated resulted from coal mining, because of exposures to naturally occurring radionuclides. Of all the collective doses evaluated, both to the public and to workers, the exposure of workers from coal mining made the largest contribution, although it has fallen over time because of improving mining conditions. By far the largest collective dose to workers per unit of electricity generated was found in the solar power cycle, followed by the wind power cycle. The reason for this is that these technologies require large amounts of rare earth metals, and the mining of low-grade ore exposes workers to natural radionuclides during mining.

Forbes- James Conca - Illinois Sees The Light – Retains Nuclear Power

The Illinois State legislature passed The Future Energy Jobs Bill (SB 2814) with less than an hour remaining in the legislative session, allowing Exelon’s Clinton and Quad Cities nuclear power plants to remain open. This will save 4,200 jobs and over 22 billion kWhs of carbon-free power each year, more than all of the state’s renewables combined.

Nextbigfuture - Coal to nuclear conversion can rapidly address 30% of CO2 emissions

High temperature nuclear reactors can replace the coal burners at several hundred supercritical coal plants in China. The lead of the pebble bed project indicates that China plans to replace coal burners with high temperature nuclear pebble bed reactors.

HTR-PM are modular reactors that will be mainly factory mass produced. The first one is taking 6 years to make. The reactor module will head towards about two years to build when they are making them by the dozen.

Nextbigfuture - China’s HTR-PM (high temperature pebble bed nuclear reactor) project is squarely aimed at being a cost-effective solution that will virtually eliminate air pollution and CO2 production from selected units of China’s large installed base of modern 600 MWe supercritical coal plants.

It is a deployment program with the first of a kind commercial demonstration approaching construction completion and commercial operation by mid to late 2018. Major parts of the machinery will be able to be merged into the existing infrastructure.

The current critical path item is the completion of the steam generators — one for each of the two reactors. The shells and internals have been completed, but the final stages of attaching the piping to the thick-walled, large diameter pressure vessels will delay site delivery until sometime close to the middle of 2017.

Nextbigfuture - In graduate school at the University of Wisconsin, Rachel Slaybaugh began studying the Boltzmann Transport Equation — “a single equation that describes where all of the neutrons are in a nuclear system,” Slaybaugh explains. “Anything in a nuclear system starts with where all of the neutrons are, so it lets you figure out everything else.”

Working with the equation can be challenging, so Slaybaugh developed expertise in creating algorithms and software to solve the equation faster and more efficiently, which ultimately can be applied to designing and modeling new nuclear technologies.

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