First measurements of chlorine 36 (Cl) wet deposition fluxes in the vicinity of Orano La Hague nuclear reprocessing plant in France.

Chlorine 36 (Cl) is a radionuclide of natural and anthropogenic origin, mainly used as a tracer in geochemical studies. Owing to analytical constraints and its low environmental levels, knowledge of Cl behavior in the environment is still very limited. In this study, we use environmental measurements to report for the first time the wet deposition fluxes of Cl downwind an anthropogenic source, the Orano nuclear reprocessing plant, which chronically emits Cl into the environment.

First quantitative constraints on chlorine 36 dry deposition velocities on grassland: Comparing measurements and modelling results.

Once released into the atmosphere, radionuclide dry deposition represents a major transfer process. It can be accurately characterized by its deposition velocity. However, this parameter is poorly constrained for most radionuclides, including chlorine 36.

Iodine uptake in brown seaweed exposed to radioactive liquid discharges from the reprocessing plant of ORANO La Hague.

Iodine-129 is present in controlled liquid radioactive waste routinely released in seawater by the ORANO nuclear fuel reprocessing plant in La Hague (Normandy, France). Brown algae are known for their exceptional ability to concentrate iodine from seawater. They also potentially emit volatile iodine compounds in response to various stresses, such as during emersion at low tide.

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.

Assessing tritium internalisation in zebrafish early life stages: Importance of rapid isotopic exchange.

"It appeared that OBT content in organisms was low with an OBT/TFWT ratio of about 8% for both stages (24 hpf and 96 hpf)." Should be read as "It appeared that OBT content in organisms was low with an OBT/TFWT ratio of about 8% and 14% at 24 hpf and 96 hphf respectively".

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).

Assessing tritium internalisation in zebrafish early life stages: Importance of rapid isotopic exchange.

Tritium (H) is mainly released into the environment in the form of tritiated water (HTO) by nuclear power plants and nuclear fuel reprocessing plants. To better understand how organisms may be affected by contamination to H it is essential to link observed effects to a correct estimation of absorbed dose rates. Due to quick isotopic exchanges between H and hydrogen, H measurement is difficult in small organisms such as zebrafish embryo, a model in ecotoxicological assay.

Tritium forms discrimination in ryegrass under constant tritium exposure: From seed germination to seedling autotrophy.

Uncertainties remain regarding the fate of atmospheric tritium after it has been assimilated in grasslands (ryegrass) in the form of TFWT (Tissue Free Water Tritium) or OBT (Organically Bound Tritium). One such uncertainty relates to the tritium forms discrimination during transfer from TFWT to OBT resulting from photosynthesis (OBT), corresponding to the OBT/TFWT ratio. In this study, the OBT/TFWT ratio is determined by experiments in the laboratory using a ryegrass model and hydroponic cultures, with constant activity of tritium in the form of tritiated water (denoted as HTO) in the "water" compartment (liquid HTO) and "air" compartment (HTO vapour in the air).

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.

Impacts of (14)C discharges from a nuclear fuel reprocessing plant on surrounding vegetation: Comparison between grass field measurements and TOCATTA-χ and SSPAM(14)C model computations.

This article compares and discusses the ability of two different models to reproduce the observed temporal variability in grass (14)C activity in the vicinity of AREVA-NC La Hague nuclear fuel reprocessing plant in France. These two models are the TOCATTA-χ model, which is specifically designed for modelling transfer of (14)C (and tritium) in the terrestrial environment over short to medium timescales (days to years), and SSPAM(14)C, which has been developed to model the transfer of (14)C in the soil-plant-atmosphere with consideration over both short and long timescales (days to thousands of years). The main goal of this article is to discuss the strengths and weaknesses of the models studied, and to investigate if modelling could be improved through consideration of a much higher level of detail of plant physiology and/or higher number of plant compartments.

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.

The TOCATTA-χ model for assessing 14C transfers to grass: an evaluation for atmospheric operational releases from nuclear facilities.

Radioactive (14)C is formed as a by-product of nuclear power generation and from the operation of nuclear fuel reprocessing plants like AREVA-NC La Hague (North France), which releases about 15 TBq per year of (14)C into the atmosphere. This article evaluates a recently improved radioecology model (TOCATTA-χ) to assess (14)C transfers to grassland ecosystems under normal operating conditions. The new version of the TOCATTA model (TOCATTA-χ) includes developments that were derived from PaSiM, a pasture model for simulating grassland carbon and radiocarbon cycling.

Modelling the transfer of 14C from the atmosphere to grass: a case study in a grass field near AREVA-NC La Hague.

Radioactive (14)C is formed as a by-product of nuclear power generation and from operation of nuclear fuel reprocessing plants like AREVA-NC La Hague (North France), which releases about 15 TBq per year of (14)C into the atmosphere. Since the autumn of 2006, (14)C activity concentrations in samples from the terrestrial environment (air, grass and soil) have been monitored monthly on grassland 2 km downwind of the reprocessing plant. The monitoring data provides an opportunity to validate radioecology models used to assess (14)C transfer to grassland ecosystems.

TOCATTA: a dynamic transfer model of ¹⁴C from the atmosphere to soil-plant systems.

Many nuclear facilities release ¹⁴C into the environment, mostly as ¹⁴CO₂, which mixes readily with stable CO₂. This complete isotopic mixing (equilibrium) is often used as the basis for dose assessment models. In this paper, a dynamic compartment model (TOCATTA) has been investigated to describe ¹⁴C transfer in agricultural systems exposed to atmospheric ¹⁴C releases from nuclear facilities under normal operating or accidental conditions.

Modelling tritium flux from water to atmosphere: application to the Loire River.

Tritium (³H or T) is one of the major radionuclides released by nuclear power plants (NPP) into rivers. However, tritiated water (HTO) flux from water to air is seldom considered when assessing health effects of such releases. The aim of this paper is to present the result of a research program, called LORA, conducted on the Loire River (France).

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.

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.

Structural and functional studies of vertebrate metallothioneins: cross-talk between domains in the absence of physical contact.

In previous studies, we showed that the chemical and dynamic properties of fish and mouse MTs (metallothioneins) present a number of distinctive differences linked to their primary structures, and that phylogenetic relationships of mammal and fish MTs correlate with their three-dimensional structures. The different behaviours of MTs may also be linked to the interaction between their two domains. In the present study, we have compared the physicochemical properties of the isolated recombinant domains constituting Notothenia coriiceps and mouse MTs, and compared them with those of the corresponding whole MTs.

In situ metrology of 85Kr plumes released by the COGEMA La Hague nuclear reprocessing plant.

The IRSN (Institut de Radioprotection et de Sûreté Nucléaire, France) has started an in situ study of the behaviour of atmospheric releases close-by the COGEMA La Hague nuclear reprocessing plant. The study is designed to improve information on the dispersion of radioactive pollutants very close to the emission point--a 100 m height chimney. In this situation, close to the emission and height of the emission, Gaussian models generally used to predict the behaviour of atmospheric releases are not well adapted.

Solution structure of MT_nc, a novel metallothionein from the Antarctic fish Notothenia coriiceps.

The structure of [113Cd(7)]-metallothionein (MT_nc) of the Antarctic fish Notothenia coriiceps, the first three-dimensional structure of a fish metallothionein, was determined by homonuclear 1H NMR experiments and heteronuclear [1H, 113Cd]-correlation spectroscopy. MT_nc is composed of an N-terminal beta domain with 9 cysteines and 3 metal ions and a carboxy-terminal alpha-domain with 11 cysteines and 4 metal ions. The position of the ninth Cys of the alpha domain of MT_nc is different from the corresponding Cys of mammalian MTs.