The environmental mobility of newly deposited radionuclides in surface soil is driven by complex biogeochemical relationships, which have significant impacts on transport pathways. The partition coefficient (Kd) is useful for characterizing the soil-solution exchange kinetics and is an important factor for predicting relative amounts of a radionuclide transported to groundwater compared to that...

We present a comprehensive geochemical data set for the most recent volcanics from the Mariana Islands, which provides new constraints on the timing and nature of fluxes from the subducting slab. The lavas display many features typical of island arc volcanics, with all samples showing large negative niobium anomalies and enrichments in alkaline earth elements and lead (e.g., high Ba/La and Pb/C...

In the mid-1990s, a groundwater plume of uranium (U) was detected in monitoring wells in the B-BX-BY Waste Management Area at the Hanford Site in Washington. This area has been used since the late 1940s to store high-level radioactive waste and other products of U fuel-rod processing. Using multiple-collector ICP source magnetic sector mass spectrometry, high-precision uranium isotopic analyses...

Saline groundwaters with 4.7 to 26%o total dissolved solids were sampled from springs and artesian wells in Mississippian and Ordovician carbonates and sandstones in central Missouri. U-Th isotopic variations provide a means of evaluating processes of water-rock interaction and fluid mixing and estimating the time scales of element transport. Recently developed mass spectrometric techniques are...

The naturally occurring primordial radionuclides in coals might exhibit high radioactivity, and can be exported to the surrounding environment during coal combustion. In this study, nine coal samples were collected from eastern Yunnan coal deposits, China, aiming at characterizing the overall radioactivity of some typical nuclides (i.e., 40K, 238U, 232Th, 226Ra) and assessing their ecological i...

The results of the study on natural radionuclide content in 102 samples of the moss species randomly collected in 2008- 2013 at 30 locations of eastern Serbia are presented in the paper. The activity concentration values of 238U, 226Ra, 232Th, 40K, and 7Be determined by gamma spectrometry were within the intervals: 238U (1.1-50) Bq kg(-1), 226Ra (1.1-41) Bq kg(-1), 232Th (1.4-28) Bq kg(-1), 40K...

Gamma-ray emission probabilities of 235U and 238U have been studied extensively. While the gamma-ray emission probabilities for 235U are well known, the emission probabilities for differ widely from one study to another. Our study indicates that one of the causes of the large discrepancies in the studies may be due to the true coincidence summing of many gamma rays from the decay of 238U daught...

Parity nonconservation (PNC) was studied for 24 p-wave neutron resonances in 238U from 10 to 300 eV by measuring the helicity dependence of the total neutron cross section with an improved experimental apparatus. Six resonances show statistically significant (greater than 2.9σ) parity violation. An analysis treating the PNC matrix elements as random variables yields a root-mean-square PNC matri...

We report the application of high-resolution in situ 238U-230Th disequilibrium dating to pyrochlore [(Ca,Na,REE,Th,U)2(Nb,Ti,Ta,Zr)2O6(OH,F)]. Compositionally zoned pyrochlore is an accessory phase in intrusive carbonatitic syenites, which were ejected as cognate clasts during the eruption of the phonolitic Laacher See volcano, East Eifel, Germany, 12.9 ka ago. Separated individual pyrochlore c...

This paper details the different steps for isotopic determination of UAmO2 discs from analytical irradiation. MARIOS and DIAMINO irradiations were performed in materials testing reactors to study behaviour americium bearing blanket samples regard heterogeneous recycling sodium-cooled fast reactor. Six irradiated dissolved hot cells analyzed determine isotope ratios uranium, plutonium, neodymium...