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The back-end of the nuclear fuel cycle: storing and transporting radioactive waste
Published in Peter R. Mounfield, World Nuclear Power, 2017
When spent fuel elements arrive at reprocessing plants they are fed into automatic decanning machines which remove the nose and tail pieces, split and peel off the cans and then chop them into pieces for storage. The decanned uranium fuel is then dissolved in nitric acid to form the nitrates of uranium, plutonium and the fission product elements. Gaseous effluents containing radionuclides or radioactive matter arise when the fuel is dissolved and from the ventilation of cells and vessels. Most prominent are krypton-85, iodine-129, carbon-14 and tritium. Their approximate content in 1 tonne of used LWR fuel after a normal burnup of 33 GW days/tonne is shown in Table 12.1. Aerosols are also produced at the stage of fuel processing. All these effluents are strongly diluted by air moving through the nitric acid and dissolving fuel. High level waste vitrification and low or intermediate level waste incineration at fuel reprocessing plants are other sources of airborne activity (e.g. caesium-137 and ruthenium-106). It is clear, therefore, that arguments for nuclear power on the grounds that it contributes less pollution to the atmosphere than coal- or oil-fired plants must be qualified by the recognition that it has its own contribution to make to environmental pollution.
The Medical Implications of Nuclear Power Plant Accidents
Published in W.A. Crosbie, J.H. Gittus, Medical Response to Effects of Ionising Radiation, 2003
Effluent released from the pipeline into the Irish Sea is dispersed by tidal action and currents. Some isotopes remain mostly mobile within the seawater (eg caesium-137), whereas others are more strongly adsorbed by silt particles (eg plutonium and ruthenium-106). Certain isotopes are ingested or adsorbed by marine flora and fauna, depending on their chemical nature, and may enter the food chain. The quantity of radioactive material taken up by any particular species will depend, among other things, on its habitat and feeding habits. Eventually, radionuclides will pass along food
Biological Transfer and Transport Processes
Published in Gunnar Kullenberg, Pollutant Transfer and Transport in the Sea, 2018
Differences in the oxidation state of metals also strongly affect their uptake characteristics. Clams accumulate more 51Cr in the hexavalent form than as the trivalent ion.63 Selenite has an affinity for mussel tissue approximately four times over that of seienate when the ions are absorbed from water.66 Ruthenium-106 chloride complexes are more available for uptake than 106Ru nitrosyl-nitrato forms in mussels68 and euphausiids.69
Analysis of Korea’s PWR Spent Nuclear Fuel (SNF) Characteristics Evaluated from Existing SNF Inventories (1979–2015) and Projected SNF Inventories (2016–2089)
Published in Nuclear Technology, 2019
Ara Go, Daesik Yook, Kyuhwan Jeong, GyeongMi Kim, GunHee Jung, Ser Gi Hong
Figure 10 shows the composition of thermal power of the reference SNF. Figure 10 lists the top 10 nuclides among 183 nuclides for each cooling time. Praseodymium-144, ruthenium-106, and cesium-134 contribute to 72% in the 1-year–cooled reference SNF and decreased to 30% in 5 years. After 10 years, they had a minor effect on heat. (90Y, 90Sr) showed a great increase in 5 years and then about 30% until 50 years, and in 100 years, they decreased to 17%. (137mBa, 137Cs) were similar to (90Y, 90Sr). Contrary to 90Y and 137mBa, 238Pu and 241Am increased with the lapse of time. Plutonium-238 increased from 2% in 5 years to 19% in 100 years, and 241Am increased from 5% in 10 years to 41% in 100 years. These results were similar to results from KAERI (Ref. 12).
Analysis of the vertical distribution and size fractionation of natural and artificial radionuclides in soils in the vicinity of hot springs
Published in Radiation Effects and Defects in Solids, 2018
S. Padovani, I. Mitsios, M. Anagnostakis, D. Mostacci
During this research the following radionuclides were detected and quantified: Lead–210 via its 46.52 keV photons.Thorium–234 via its 63.29 keV photons, used to evaluate Uranium–238 concentration activity.Thorium–228 was calculated by weighting Lead–212 (283.63 keV) and Thallium–208 (583.14 keV) activity concentrations.Radium–226 activity concentration was calculated by weighting the activity concentrations of two of its short–lived decay products: Lead–214 (295.22 keV and 351.99 keV) and Bismuth–214 (609.32 keV, 1120.28 keV and 1764.51 keV).Radium–228 was determined under the assumption of radioactive equilibrium with Actinium–228 (338.40 and 911.07keV).Cesium–137 via its 661.66 keV photons.Potassium–40 via its 1460.75 keV photons.Beryllium–7 via its 477.6 keV photons.Ruthenium–106 was determined under the assumption of radioactive equilibrium with Rhodium–106 (621.8 keV). Due to Rhodium–106 short half–life (30.10 s) Ruthenium–106 and Rhodium–106 are practically always in equilibrium in environmental samples.