... of leesite resembles the previously described, but poorly understood mineral, paraschoepite. Uptake of dangerous radionuclides ( 90 Sr, 135 Cs, 137 Cs, 237 Np, 238 Pu) into the structure of leesite and other members of the family has important implications for the safe disposal of nuclear waste...

...Fig. 6. Variation of log( K d ) of 233 U, 241 Am, 239 Pu and 238 Np present in different phases of the speleothem and CaCO 3 minerals from the literature as a function of pH. ...

... at 90 °C: implications for the corrosion of spent nuclear fuel. Journal of Nuclear Materials , 238 , 78 –95. The crystal chemistry of Np 5+ is similar to that of U 6+ in that nearly linear actinyl ions dominate in each case, and the neptunyl and uranyl ions are of similar size. Neptunium...

... solution, for another 180 seconds. The data were acquired in time resolved — peak jumping — pulse counting mode with 1 point measured per peak for masses 202 (flyback), 203 and 205 (Tl), 206 and 207 (Pb), 209 (Bi), 233 (U), 237 (Np), 238 (U), 249 ( 233 U oxide), 253 ( 237 Np oxide) and 254 ( 238 U oxide...

... optimized to ensure that only the mass of interest was included in the mass window. Initially, becquerelite crystals grown in the absence of Np were analyzed to verify that there is no interference of the 238 mass isotope of U with the 237 mass window selected for the analysis. The count rate for mass 238...

... Toarcian Kanense–Planulata 7 Ashcroft 1 Rattlesnake Hill 625000 5624200 C-178148 cs Proximal Pliensbachian Kunae 8 2 Lundblom Lake 672100 5559850 NP-2000-15 cs Proximal Early Jurassic 3 Semlin Hill 624450 5624600 C-178149 cs Proximal basin Bajocian Kirschneri 8, 9...

... with CN = 4 (238–246 pm), and 5 (253–265 pm), and U–O s bonds to the O m centers of 249–261 pm ( Table 2 ). The two groups of U–O distances (shorter and longer) are rather distinct, especially for the complexes with CN = 5. Although equatorial Np–O distances followed the same trend as for U–O...

... in the early 1990s when dry, contaminated sediments were collected directly from the base of the drained North Process Pond in two locations (NP 1 and NP 4). Samples were collected over depth at both locations; we include a single image (see “Results and Discussion,” below) for a reference sample from...

... grown in the absence of Np (Na-MS-CRY) were analyzed to verify that there is no interference of the 238 mass isotope of U with the 237 mass window selected for the analysis. The results for a crystal of Na-MS-CRY-Np are shown in Figure 2 , taken from Burns and Klingensmith (2006) . F igure 2...

...-Tethys in the Pamir plateau. Integrating this study with previous studies, we construct a more detailed Paleo-Tethys evolution process of the Pamir Plateau. The Pamir plateau is divided into three main tectonic units, from north to south, the Northern Pamir (NP), the Central Pamir (CP...

... their crustal abundances are extremely small (10 −10 to 10 −6 ppm). The crustal abundances of Pu, Np, Cm and Am are essentially zero, although minute quantities of Pu and Np form in uranium deposits by neutron capture on 238 U and subsequent β-decay, continuing to the formation of 235 U by α-decay...

... Pb/ 238 U age 1σ error % Discordance Mean group age U/Th 207 Pb/ 235 U % error 206 Pb/ 238 U % error Error correction (Ma) NP-43 (c) 0.6503 2.93 0.0815 2.8 0.94 505.3 13.4 4 4 NP-46 (c) 0.6661 3.08 0.0823 2.8 0.905 509.7 13.7 9 2 NP-67 (r) 0.6411...

.../ 206 Pb 1σ 207 Pb/ 235 U 1σ 206 Pb/ 238 U 1σ 207 Pb/ 206 Pb age (Ma) 1σ 207 Pb/ 235 U age (Ma) 1σ 206 Pb/ 238 U age (Ma) 1σ 176 Lu/ 177 Hf 2σ 176 Hf/ 177 Hf 2σ ε Hf ( t ) T DM2 (Ga) NP-5 (Napeng pluton):  1.1 60 843 .07 .05244 .00091 .29871 .00561 .04132...

... power plant. The energy of the neutron spectrum can be adjusted so that higher-energy (>1 MeV) “fast” neutrons can be used to fission 238 U and the “minor” actinides, such as Np, Cm, and Am. The final composition of the fuel depends on the initial fuel type, chemical composition, the level...

... for 200 seconds. The data were acquired in time-resolved peak-jumping, pulse-counting mode with one point measured per peak for masses 202 (Hg, flyback), 203 (Tl), 205 (Tl), 206 (Pb), 207 (Pb), 208 (Pb), 209 (Bi), 232 (Th), 233 (U), 237 (Np), 238 (U), 248 ( 232 Th 16 O), 249 ( 233 U 16 O), 253 ( 237 Np 16...

... of new reactor designs and advanced fuel cycles, which rely on extensive, multiple reprocessing schemes, some of the important “waste” radionuclides, such as Pu and Np, may be eliminated; in other schemes, they may be generated as new fissile material ( 239 Pu from 238 U or 233 U from 232 Th). Most...

...-sericite schists that were metamorphosed under regional greenschist facies conditions and belong to the Tokma (Gorevka) Formation (NP 1–2 ) ( Kachevsky et al., 1998 ). The host rocks were deformed due to lateral strain in a W–E direction (geographic coordinates), forming inclined asymmetrical N–S-trending...

... of 237 U, 238 U, and 242 U were determined in five measurement cycles. The average values were calculated from these measurements, and the standard deviations represent the short-term precision of the ICP-MS. The final 237 Np and 242 Pu concentrations in the spike solution, calculated as the weighted...

... fission of U in fuel rods in nuclear reactors. The radionuclides generated in those reactions can be separated into fission products (including 137 Cs, 90 Sr and 99 Tc) and actinides (e.g. 238 U, 238 Pu, 239 Pu, 240 Pu, 241 Pu, 237 Np and 241 Am). Of these, 137 Cs and 90 Sr have relatively...