Recent evolution of 129-I levels in the Nordic Seas and the North Atlantic Ocean

Most of the anthropogenic radionuclide 129I released to the marine environment from the nuclear fuel reprocessing plants (NFRP) at Sellafield (England) and La Hague (France) is transported to the Arctic Ocean via the North Atlantic Current and the Norwegian Coastal Current. 129I concentrations in seawater provides a powerful and well-established radiotracer technique to provide information about the mechanisms which govern water mass transport in the Nordic Seas and the Arctic Ocean and is gaining importance when coupled with other tracers (e.g. CFC, 236U). In this work, 129I concentrations in surface and depth profiles from the Nordic Seas and the North Atlantic (NA) Ocean collected from four different cruises between 2011 and 2012 are presented. This work allowed us to i) update information on 129I concentrations in these areas, required for the accurate use of 129I as a tracer of water masses; and ii) investigate the formation of deep water currents in the eastern part of the Nordic Seas, by the analysis of 129I concentrations and temperature-salinity (T-S) diagrams from locations within the Greenland Sea Gyre. In the Nordic Seas, 129I concentrations in seawater are of the order of 109 at·kg− 1, one or two orders of magnitude higher than those measured at the NA Ocean, not so importantly affected by the releases from the NFRP. 129I concentrations of the order of 108 atoms·kg− 1 at the Ellet Line and the PAP suggest a direct contribution from the NFRP in the NA Ocean. An increase in the concentrations in the Nordic Seas between 2002 and 2012 has been detected, which agrees with the temporal evolution of the 129I liquid discharges from the NFRPs in years prior to this. Finally, 129I profile concentrations, 129I inventories and T-S diagrams suggest that deep water formation occurred in the easternmost area of the Nordic Seas during 2012.Ministerio de Economía y Competitividad FIS2015-69673-

I+D para detectar isótopos de difícil medida

Desde que el Centro Nacional de Aceleradores (CNA) abriera sus puertas en 1997, los investigadores españoles cuentan con un laboratorio de referencia para estudiar la caracterización y modificación de materiales. Uno de los proyectos que allí se desarrollan consiste en medir isótopos radiactivos, lo que con las técnicas empleadas hasta ahora no se había conseguido. Se trata de un estudio en el que coopera Enresa, empresa con la que el CNA selló un convenio de colaboración en 2008, y cuyos resultados contribuirán a mejorar la seguridad en el almacenamiento de los residuos.Since the National Accelerators Centre (NAC) opened its doors in 1997, Spanish researchers have had use of a reference centre to study the characterisation and modification of materials. One of the projects developed there has been to measure radioactive isotopes that have not been measured using the techniques employed to da te. This study involves the cooperation of Enresa, with which the NAC established a collaboration agreement in 2008, and the results of which may help to improve the safe storage of waste

Long-lived radionuclides in residues from operation and decommissioning of nuclear power plants

Radioactive residues, in order to be classified as Low-Level Waste (LLW), need to fulfil certain conditions; the limitation of the maximum activity from long-lived radionuclides is one of these requirements. In order to verify compliance to this limitation, the abundance of these radionuclides in the residue must be determined. However, performing this determination through radiometric methods constitutes a laborious task. In this work, 129I concentrations, 239+240Pu activities, and 240Pu/239Pu ratios are determined in low-level radioactive residues, including resins and dry sludge, from nuclear power plants in Spain. The use of Accelerator Mass Spectrometry (AMS) enables high sensitivities to be achieved, and hence these magnitudes can be re determined with good precision. Results present a high dispersion between the 129I and 239+240Pu activities found in various aliquots of the same sample, which suggests the existence of a mixture of resins with a variety of histories in the same container. As a conclusion, it is shown that activities and isotopic ratios can provide information on the processes that occur in power plants throughout the history of the residues. Furthermore, wipes from the monitoring of surface contamination of the José Cabrera decommissioning process have been analyzed for 129I determination. The wide range of measured activities indicates an effective dispersal of 129I throughout the various locations within a nuclear power plant. Not only could these measurements be employed in the contamination monitoring of the decommissioning process, but also in the modelling of the presence of other iodine isotopes.Ministerio de Ciencia e Innovación FIS2008-0114

Recent evolution of 129 I levels in the Nordic Seas and the North Atlantic Ocean

Most of the anthropogenic radionuclide 129I released to the marine environment from the nuclear fuel reprocessing plants (NFRP) at Sellafield (England) and La Hague (France) is transported to the Arctic Ocean via the North Atlantic Current and the Norwegian Coastal Current. 129I concentrations in seawater provides a powerful and well-established radiotracer technique to provide information about the mechanisms which govern water mass transport in the Nordic Seas and the Arctic Ocean and is gaining importance when coupled with other tracers (e.g. CFC, 236U). In this work, 129I concentrations in surface and depth profiles from the Nordic Seas and the North Atlantic (NA) Ocean collected from four different cruises between 2011 and 2012 are presented. This work allowed us to i) update information on 129I concentrations in these areas, required for the accurate use of 129I as a tracer of water masses; and ii) investigate the formation of deep water currents in the eastern part of the Nordic Seas, by the analysis of 129I concentrations and temperature-salinity (T-S) diagrams from locations within the Greenland Sea Gyre. In the Nordic Seas, 129I concentrations in seawater are of the order of 109 at·kg− 1, one or two orders of magnitude higher than those measured at the NA Ocean, not so importantly affected by the releases from the NFRP. 129I concentrations of the order of 108 atoms·kg− 1 at the Ellet Line and the PAP suggest a direct contribution from the NFRP in the NA Ocean. An increase in the concentrations in the Nordic Seas between 2002 and 2012 has been detected, which agrees with the temporal evolution of the 129I liquid discharges from the NFRPs in years prior to this. Finally, 129I profile concentrations, 129I inventories and T-S diagrams suggest that deep water formation occurred in the easternmost area of the Nordic Seas during 2012

Estimating the impact from Fukushima in Southern Spain by I-131 and Accelerator Mass Spectrometry detection of I-129

Parte del número especial: Environmental Radioactivity – New Challenges with New Analytical Technologies Selected papers presented at the ENVIRA2015 ConferenceAfter the Fukushima accident, large amounts of radionuclides were discharged to the atmosphere. Some of them travelled long distances and were detected in places as far from Japan as Spain a few days after the accident. One of these radionuclides was 131I. Its isotope 129I (T1/2 = 15.7 × 106 years) was also expected to follow the same pathway. In this work, we present the results for the 129I concentration in the same atmospheric samples from Seville (Spain) where 131I activity was measured in 2011 by Baeza et al. (2012). 129I concentrations in aerosol and gaseous samples showed concentrations in the order of 104 and 105 atoms/m3, typically higher in the gaseous form with respect to the aerosol form. Also 129I in rainwater was measured, showing concentrations in the order of 108 atoms/L. The results show a very good agreement with the 131I profile, showing that, if background from other sources is not relevant, it is possible to estimate the impact of similar events years after them thanks to the sensitivity of techniques like Accelerator Mass Spectrometry.Junta de Andalucía P10-FQM-5956Ministerio de Economía y Competitividad FIS2012-31853Ministerio de Economía y Competitividad FIS2015-69673-

Recent evolution of 129I levels in the Nordic Seas and the North Atlantic Ocean

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