Flux of tritium from the sea to the atmosphere around a nuclear reprocessing plant: Experimental measurements and modelling for the Western English channel.

Tritium is released to the environment by nuclear industries in various forms, mainly HTO. In impact studies leading to estimated doses for the population, atmospheric discharges are mainly taken into consideration because they generally lead to values higher than those related to liquid discharges. However, the tritium released in liquid environments can be transferred to the atmosphere by evaporation and then be transported to terrestrial ecosystems by wind.

Experimental measurements of the bacterial oxidation of HT in soils: Impact over a zone influenced by an industrial release of tritium in HT form.

Tritium is a radionuclide released to the atmosphere by nuclear industries in various forms, mainly HTO and to a lesser extent HT. However, some nuclear sites may emit predominantly HT in the atmosphere. The HT is oxidized to HTO essentially in the top cm of soils, and that the formed HTO is then possibly released into the atmosphere.

Measurement and modelling of gaseous elemental iodine (I) dry deposition velocity on grass in the environment.

Assessing the impact of radioactive iodine on humans subsequent to a nuclear accident requires a better understanding of its behaviour in the environment. An original approach aimed at developing a model constrained by data collected during experimental campaigns has been developed. These experimental campaigns, named MIOSEC 2 and MIOSEC 3 respectively, were conducted in the middle of grassland.

Tritium in precipitation on 5 sites in North-West France during the 2017-2019 period.

Between October 2017 and May 2019, measurements of tritium in rainwater were carried out at several sites in north-west France. Tritium is an important tracer for hydroclimatic studies and this work provided up-to-date data that we compared with Global Network for Isotopes in Precipitation (GNIP) measurements. Of the various sites studied, some could potentially be affected by atmospheric gaseous emissions from the nuclear industries in the region (reprocessing plant, nuclear power plant).

Atmospheric tritium concentrations under influence of AREVA NC La Hague reprocessing plant (France) and background levels.

In-air tritium measurements were conducted around the AREVA NC La Hague reprocessing plant, as well as on other sites that are not impacted by the nuclear industry in northwest of France. The results indicate that the dominant tritium form around the AREVA site is HT (86%). HT and HTO levels are lower than 5 and 1 Bq.

The VATO project: Development and validation of a dynamic transfer model of tritium in grassland ecosystem.

In this paper, a dynamic compartment model with a high temporal resolution has been investigated to describe tritium transfer in grassland ecosystems exposed to atmospheric H releases from nuclear facilities under normal operating or accidental conditions. TOCATTA-χ model belongs to the larger framework of the SYMBIOSE modelling and simulation platform that aims to assess the fate and transport of a wide range of radionuclides in various environmental systems. In this context, the conceptual and mathematical models of TOCATTA-χ have been designed to be relatively simple, minimizing the number of compartments and input parameters required.

The VATO project: An original methodology to study the transfer of tritium as HT and HTO in grassland ecosystem.

Tritium (H) is mainly released into the environment by nuclear power plants, military nuclear facilities and nuclear reprocessing plants. The construction of new nuclear facilities in the world as well as the evolution of nuclear fuel management might lead to an increase of H discharges from the nuclear industry. The VATO project was set up by IRSN (Institut de Radioprotection et de Sûreté Nucléaire) and EDF (Electricité de France) to reduce the uncertainties in the knowledge about transfers of H from an atmospheric source (currently releasing HT and HTO) to a grassland ecosystem.

In situ measurements of tritium evapotranspiration (³H-ET) flux over grass and soil using the gradient and eddy covariance experimental methods and the FAO-56 model.

The behaviour of tritium in the environment is linked to the water cycle. We compare three methods of calculating the tritium evapotranspiration flux from grassland cover. The gradient and eddy covariance methods, together with a method based on the theoretical Penmann-Monteith model were tested in a study carried out in 2013 in an environment characterised by high levels of tritium activity.

Near-field krypton-85 measurements in stable meteorological conditions around the AREVA NC La Hague reprocessing plant: estimation of atmospheric transfer coefficients.

The aim of this work was to study the near-field dispersion of (85)Kr around the nuclear fuel reprocessing plant at La Hague (AREVA NC La Hague - France) under stable meteorological conditions. Twenty-two (85)Kr night-time experimental campaigns were carried out at distances of up to 4 km from the release source. Although the operational Gaussian models predict for these meteorological conditions a distance to plume touchdown of several kilometers, we almost systematically observed a marked ground signal at distances of 0.

Comparison of RIMPUFF, HYSPLIT, ADMS atmospheric dispersion model outputs, using emergency response procedures, with (85)Kr measurements made in the vicinity of nuclear reprocessing plant.

The Institut de Radioprotection et de Sureté Nucléaire (IRSN) performed a series of (85)Kr air sampling campaigns at mesoscale distances (18-50 km) from the AREVA NC La Hague nuclear reprocessing plant (North West France) between 2007 and 2009. The samples were collected in order to test and optimise a technique to measure low krypton-85 ((85)Kr) air concentrations and to investigate the performance of three atmospheric dispersion models (RIMPUFF, HYSPLIT, and ADMS), This paper presents the (85)Kr air concentrations measured at three sampling locations which varied from 2 to 8000 Bq m(-3), along with the (85)Kr air concentrations output by the dispersion models. The dispersion models made reasonable estimates of the mean concentrations of (85)Kr field measurements during steady wind conditions.

Tracking of airborne radionuclides from the damaged Fukushima Dai-ichi nuclear reactors by European networks.

Radioactive emissions into the atmosphere from the damaged reactors of the Fukushima Dai-ichi nuclear power plant (NPP) started on March 12th, 2011. Among the various radionuclides released, iodine-131 ((131)I) and cesium isotopes ((137)Cs and (134)Cs) were transported across the Pacific toward the North American continent and reached Europe despite dispersion and washout along the route of the contaminated air masses. In Europe, the first signs of the releases were detected 7 days later while the first peak of activity level was observed between March 28th and March 30th.

A study of the atmospheric dispersion of a high release of krypton-85 above a complex coastal terrain, comparison with the predictions of Gaussian models (Briggs, Doury, ADMS4).

Atmospheric releases of krypton-85, from the nuclear fuel reprocessing plant at the AREVA NC facility at La Hague (France), were used to test Gaussian models of dispersion. In 2001-2002, the French Institute for Radiological Protection and Nuclear Safety (IRSN) studied the atmospheric dispersion of 15 releases, using krypton-85 as a tracer for plumes emitted from two 100-m-high stacks. Krypton-85 is a chemically inert radionuclide.

Solid partitioning and solid-liquid distribution of 210Po and 210Pb in marine anoxic sediments: roads of Cherbourg at the northwestern France.

A sequential extraction protocol has been used to determine the solid-phase partition of (210)Po and (210)Pb in anoxic marine sediment from the roads of Cherbourg (France) in the central English Channel. Measurements were also obtained in pore waters, in which (210)Po activities range between 1 and 20 mBq L(-1) and (210)Pb activities between 2.4 and 3.

Metals in marine environment (mollusc Patella sp., fish Labrus bergylta, crustacean Cancer pagurus, beach sand) in a nuclear area, the North Cotentin (France).

The results of a 1-year long survey of trace metals concentrations (Al, Cd, Cr, Co, Cu, Fe, Mn, Hg, Ni, Pb, Zn) measured in beach sand, limpets and, occasionally, in fish and shellfish from the North Cotentin area (France), where nuclear industries are implanted, are presented. The objective of these study was to provide useful data for the validation of models predicting the impact of these industries on the marine environment. Even if differences were noted between sites for various metals, the levels are consistent with existing data published for similar site and do not appear to give evidence of contamination by industrial sites.

Water to atmosphere fluxes of 131I in relation with alkyl-iodide compounds from the Seine Estuary (France).

This study presents an original work on measurements of stable and radioactive iodinated species in the Seine estuary (France), with estimates fluxes of volatile gaseous species from water to the atmosphere. Various iodinated compounds were identified in water and air in particular 131I in water, what is unusual. Concentrations and behaviour of iodinated elements in the Seine estuary seem similar to what has been observed in other European estuaries.

Variations of 210Po and 210Pb in various marine organisms from Western English Channel: contribution of 210Po to the radiation dose.

Measurements of (210)Po were carried out in various marine matrices (mussels, oysters, seaweed, fish, and abalones) and in seawater at several points along the French coast, over a period of 2 years (2003-2005). These measurements contribute to a better knowledge of this element, since few recent data exist for the French coast. Marked seasonal variations have been revealed in some species and there are differences according to the way of life of these species.