4 ms·

This is not actually correct. See this NRC publication "Radioactive Effluents From Nuclear Power Plants: Annual Report 2008." https://www.nrc.gov/docs/ML1036/M

This is not actually correct. See this NRC publication "Radioactive Effluents From Nuclear Power Plants: Annual Report 2008." https://www.nrc.gov/docs/ML1036/ML103620452.pdf https://www.nrc.gov/docs/ML1036/ML103620452.pdf Power reactors discharge a small amount of radioactive material into the environment under normal operating conditions. See figures 4.1 through 4.12 in the report. The Palo Verde Nuclear Generating Station in Arizona [0] released 1844 curies of radionuclides in a year from gaseous, liquid, and particulate discharges. In SI units, that's 6.8 * 10^13 becquerels. According to the World Nuclear Association, a kilogram of coal ash contains about 2000 becquerels of radioactive material [1]. In 2012, the United States coal fleet generated about 110 million tons of coal ash [2]. In 2012, the United States generated 1514 terawatt hours of electricity from coal [3]. That puts the coal ash radioactive burden to the environment at roughly 1.45 * 10^11 becquerels per TWh of electricity generated in coal plants. The Palo Verde annual radioactive effluent discharge of 6.8 * 10^13 becquerels from an average of 32.3 TWh electricity generation [0] comes to 21 * 10^ 11 becquerels per TWh of electricity. Its radioactive discharge to the environment is significantly higher than the average discharged via coal ash to produce an equivalent amount of electricity. However, before getting alarmed, see figure 2.1 in the NRC Radioactive Effluents report that I linked at the beginning of this post. Even though nuclear plant effluent adds more radiation to the environment than coal ash does, industrial sources of radiation (including nuclear plants) account for about 0.1% of general population radiation exposure. Natural background sources add up to about 50%. So the marginal danger of radioactive exposure from normally operating nuclear plants or coal ash dumps is very small. People who say that coal plants emit more radiation than nuclear plants are not helping to counter "radiophobia." They are in fact attempting to exploit "radiophobia" to stir up fear over a very minor aspect of coal's environmental harms. (And coal really is an environmental disaster in many other ways.) Worse, people making this argument are not even correct about the underlying numbers. Many of them are just parroting a Scientific American article [4] which itself is a misleadingly garbled retelling of an actual research report [5] [6]. [0] https://en.wikipedia.org/wiki/Palo_Verde_Nuclear_Generating_Station https://en.wikipedia.org/wiki/Palo_Verde_Nuclear_Generating_... [1] http://www.world-nuclear.org/uploadedFiles/org/Features/Radiation/1_RadiationandRadioactivity(2).pdf http://www.world-nuclear.org/uploadedFiles/org/Features/Radi... [2] https://www.epa.gov/coalash https://www.epa.gov/coalash [3] https://en.wikipedia.org/wiki/Energy_in_the_United_States#Electricity_generation_by_source https://en.wikipedia.org/wiki/Energy_in_the_United_States#El... [4] "Coal Ash Is More Radioactive Than Nuclear Waste" https://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/ https://www.scientificamerican.com/article/coal-ash-is-more-... [5] "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants" https://science.sciencemag.org/content/202/4372/1045 https://science.sciencemag.org/content/202/4372/1045 [6] Detailed examination of what the authors were actually reporting in "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants" via my past comment here: https://news.ycombinator.com/item?id=14466887 https://news.ycombinator.com/item?id=14466887

pas 7y ago
Wow, thanks for getting the details and sources. Do we have data/studies on the health effect comparison of the radioactive portion of emitted coal ash and the typical emitted/discharged effluents of a nuclear power plant? Eg. isn't the NPP discharge much more localized so it affects a lot less people? Or both kinds have some of this and some of that and the gases are carried well with the wind anyway?
- philipkglass 7y ago
  Most of the NPP radionuclide discharge is in the form of highly mobile tritium and noble gas fission products. Since these radionuclides do not accumulate biologically, they rapidly dilute to levels that translate into very low human exposure. Most of the discharge from coal plants modeled in "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants" was from traces of radium discharged from the smoke stack along with other combustion products. Since radium behaves chemically like calcium, and is taken up into plants and the bones of people who eat those plants, it can have a much greater effect on human radiation exposure even though the coal plant discharging fewer curies of radioactive material to the environment. A modern do-over of the 1978 study would need to take into account a few things: - Smokestack emissions of radionuclides from coal have been incidentally reduced by other anti-pollution measures required on coal power plants in the US. Ash precipitators, SO2 scrubbing, and mercury scrubbing will all cut down somewhat on radium escaping via the smokestack. (None of this helps with coal's CO2 profile, but it does reduce other pollution hazards.) - Operational changes have reduced how much effluent nuclear power plants discharge into the environment -- even if the plant was already built in the 1970s. It should use more recent effluent numbers like those in "Radioactive Effluents From Nuclear Power Plants: Annual Report 2008" rather than 1970s NPP effluent numbers. - Locality of food production/consumption has decreased since 1978. The original study assumed that people ate food grown in the same region they live in, so that radioactive effluents from power plants affected local populations via the agricultural food chain. It will change if people living near a power plant in Maryland are eating foods mostly produced out-of-state.
  - pas 7y ago

pas 7y ago

Wow, thanks for getting the details and sources. Do we have data/studies on the health effect comparison of the radioactive portion of emitted coal ash and the typical emitted/discharged effluents of a nuclear power plant? Eg. isn't the NPP discharge much more localized so it affects a lot less people? Or both kinds have some of this and some of that and the gases are carried well with the wind anyway?

philipkglass 7y ago
Most of the NPP radionuclide discharge is in the form of highly mobile tritium and noble gas fission products. Since these radionuclides do not accumulate biologically, they rapidly dilute to levels that translate into very low human exposure. Most of the discharge from coal plants modeled in "Radiological Impact of Airborne Effluents of Coal and Nuclear Plants" was from traces of radium discharged from the smoke stack along with other combustion products. Since radium behaves chemically like calcium, and is taken up into plants and the bones of people who eat those plants, it can have a much greater effect on human radiation exposure even though the coal plant discharging fewer curies of radioactive material to the environment. A modern do-over of the 1978 study would need to take into account a few things: - Smokestack emissions of radionuclides from coal have been incidentally reduced by other anti-pollution measures required on coal power plants in the US. Ash precipitators, SO2 scrubbing, and mercury scrubbing will all cut down somewhat on radium escaping via the smokestack. (None of this helps with coal's CO2 profile, but it does reduce other pollution hazards.) - Operational changes have reduced how much effluent nuclear power plants discharge into the environment -- even if the plant was already built in the 1970s. It should use more recent effluent numbers like those in "Radioactive Effluents From Nuclear Power Plants: Annual Report 2008" rather than 1970s NPP effluent numbers. - Locality of food production/consumption has decreased since 1978. The original study assumed that people ate food grown in the same region they live in, so that radioactive effluents from power plants affected local populations via the agricultural food chain. It will change if people living near a power plant in Maryland are eating foods mostly produced out-of-state.
- pas 7y ago