1
|
Hassanpour M, Khezripour S, Rezaie M, Hassanpour M, Rashed Iqbal Faruque M, Uddin Khandaker M. The efficacy of thick gas electron multiplier detector in measuring 14C for dating purpose. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110288] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
2
|
Yadav P, Le Dizès S. Intercomparison of model predictions of 14C concentrations in agricultural plants following acute exposures to airborne 14C. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 248:106886. [PMID: 35472689 DOI: 10.1016/j.jenvrad.2022.106886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/24/2022] [Accepted: 04/07/2022] [Indexed: 06/14/2023]
Abstract
Carbon-14 (14C) is one of the main radionuclides released during normal operation by nuclear power plants, nuclear defense facilities and nuclear fuel reprocessing plants. It is mainly released in the form of carbon dioxide gas denoted 14CO2, which has the specificity of being incorporated into food webs via photosynthesis by primary producing organisms. In order to better assess the environmental and human impacts of 14CO2 under normal operating conditions - or after potential accidental releases - from nuclear facilities, it is necessary to improve our understanding and our predictions of the behaviour of this radionuclide along the human food chain. To achieve this goal, the International Atomic Energy Agency (IAEA) Environmental Modelling for Radiation Safety (EMRAS) model evaluation programme included the Tritium and 14C Working Group (TCWG) which dealt with the intercomparison exercises between several models of environmental transfer in the case of routine and accidental releases of these radionuclides into the environment, and their performance testing. The TOCATTA-χ model developed at IRSN is a dynamic compartment model with high temporal resolution, which simulates the transfer of 14C (and tritium) in grassland ecosystems exposed to gaseous 14CO2 (and HTO) from nuclear facilities under normal or accidental operating conditions. Following this work, IRSN proposed a related project to extend the application of the TOCATTA-χ model to 14C estimates in leafy vegetables, fruits and roots. This article deals with the application of the TOCATTA-χ model to a specific real-case scenario identified within the framework of the TCWG. The scenario provides experimental data and predicted results from models developed at the international level. Model-model and model-data intercomparison exercises were thus carried out to validate the evaluations of the TOCATTA-χ model. In addition, this paper discusses the parameterization of the TOCATTA-χ model for this scenario and the development of modules for 14C concentrations in potato tubers, based on the assumption that photosynthetic transfer occurs directly from leaves to tubers and depends mainly on the growth stage of the tubers. It is observed that the predictions of the TOCATTA-χ model for the concentrations of 14C in leaves and tubers are slightly better than the other models due to the modelling approaches adopted by TOCATTA-χ for the calculation of key ecophysiological processes that govern plant functioning. Overall, the TOCATTA-χ model reduces the Root Mean Square Error (RMSE) by a factor of less than 8 compared to other models. In addition, most of the predicted results of the TOCATTA-χ model better match the measurements and are within the measurement uncertainty limit, while a few are overestimated. This could be due to the high uncertainty associated with the experimentally measured 14C activities, which reflects the field variability in plant growth rate.
Collapse
Affiliation(s)
- Pratibha Yadav
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Reactor Safety Division, Bautzner Landstrasse 400, 01328, Dresden, Germany; Institut de Radioprotection et de Sûrete Nucleaire (IRSN), PSE-ENV/SRTE/LR2T, Laboratoire de Recherche sur les Transferts des radionucleides dans les écosystèmes Terrestres, CEN Cadarache, Saint Paul Lez Durance, 13115, France.
| | - Séverine Le Dizès
- Institut de Radioprotection et de Sûrete Nucleaire (IRSN), PSE-ENV/SRTE/LR2T, Laboratoire de Recherche sur les Transferts des radionucleides dans les écosystèmes Terrestres, CEN Cadarache, Saint Paul Lez Durance, 13115, France
| |
Collapse
|
3
|
Nicoulaud-Gouin V, Mourlon C, Tanaka T, Le Dizes-Maurel S, Garcia-Sanchez L, Attard JC, Zorko B, Mora JC, Simon-Cornu M. Sensitivity analysis in a radiological impact assessment of a nuclear power plant discharge. A comparison of the Morris, Spearman and Sobol' approaches. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 242:106770. [PMID: 34864504 DOI: 10.1016/j.jenvrad.2021.106770] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 09/10/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
This paper compares the Morris, Spearman and Sobol' methods of sensitivity analysis in radiological risk assessment. The determination of the most influential parameters on model with regards to the propagation of their uncertainties to output variables, is of greatest interest. This study aims to determine the relative importance of parameters uncertainties on the dose calculation uncertainty in the framework of a scenario of routine discharges discussed in the context of an IAEA working group. The scenario considers atmospheric and liquid discharges of three different types of radionuclides (14C, tritium as HTO and 110mAg) from a nuclear power plant located by the side of a river. It is concluded that the most reliable and practical method according to the ability of ranking influential parameters and the easiness of its application is the Spearman method. As key result, the three first influential variables for annual total dose for all pathways and all radionuclides were the water dissolved inorganic carbon concentration, the volatilisation rate constant and the soil layer solid liquid distribution in 14C.
Collapse
Affiliation(s)
- V Nicoulaud-Gouin
- Institut de Radioprotection et de Sûreté Nucléaire, IRSN, PSE-ENV, SRTE, LRTA, Cadarache, France.
| | - C Mourlon
- Institut de Radioprotection et de Sûreté Nucléaire, IRSN, PSE-ENV, SEREN, LEREN, Cadarache, France
| | - T Tanaka
- EDF R&D, LNHE, 6 Quai Watier, 78400, Chatou, France
| | - S Le Dizes-Maurel
- Institut de Radioprotection et de Sûreté Nucléaire, IRSN, PSE-ENV, SRTE, LR2T, Cadarache, France
| | - L Garcia-Sanchez
- Institut de Radioprotection et de Sûreté Nucléaire, IRSN, PSE-ENV, SRTE, LR2T, Cadarache, France
| | - J C Attard
- Institut de Radioprotection et de Sûreté Nucléaire, IRSN, PSE-ENV, SRTE, LRTA, Cadarache, France
| | - B Zorko
- Jozef Stefan Institute, Jamova Cesta, 39, 1000, Ljubljana, Slovenia
| | - J C Mora
- UPRPYMA, CIEMAT, Avda. Complutense 40, 28040, Madrid, Spain
| | - M Simon-Cornu
- Institut de Radioprotection et de Sûreté Nucléaire, IRSN, PSE-ENV, SEREN, Cadarache, France
| |
Collapse
|
4
|
Audrey S, Virginie C, Isabelle C, Philippe C, Frédéric A. Short-term accumulation and elimination of carbon-14 in the common carp Cyprinus carpio under laboratory conditions. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 233:106585. [PMID: 33761388 DOI: 10.1016/j.jenvrad.2021.106585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/17/2021] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
This study examined the short term transfer of carbon-14 (14C) in the common carp Cyprinus carpio under laboratory conditions. Various experiments were achieved in order to investigate direct or trophic transfer for 4 days, using waterborne 14C-labelled arginine or 14C-labelled food pellets respectively. Radiolabelled food was prepared with 14C-labelled arginine or glucose in order to test how transfer kinetics might vary with the biochemical form of 14C. Elimination experiments were achieved using fish fed for 5 days on radiolabelled food and then placed under starvation for 4 days. In all experiments, water, food and fish activities were monitored every day. Different fish fractions (whole body, muscle) were sampled in order to elucidate the role of muscle as a potential storage. Results suggested that direct water-to-fish absorption rate was 20% d-1 per fish. Carps incorporated 14.3% of the absorbed 14C. Fish activity did not increase over days, due to a strong decrease in 14C concentration in the water (resulting from aquarium sorption). During trophic transfer experiments, food was entirely ingested and 14C sources rapidly assimilated. For either arginine or glucose, results suggested that 19-20% of ingested 14C was incorporated, yielding a significant increase in fish activity over days. No difference in mass-specific activity was observed among muscle and whole body. Total activity in the muscle represented 29%-32% of whole body activity, this proportion reflecting the contribution of muscle to whole body weight. During elimination experiments, results showed a significant decrease in whole body total activity and mass-specific activity with arginine. The decrease was not significant with glucose due to a great variability among fish. Results suggested that an essential amino-acid like arginine can be used as an energy source under starvation and that muscles can act as a storage for essential amino-acids.
Collapse
Affiliation(s)
- Souloumiac Audrey
- LECO, IRSN, PSE-ENV, SRTE, Cadarache, BP3, 13115, Saint-Paul-lez-Durance, France
| | - Camilleri Virginie
- LECO, IRSN, PSE-ENV, SRTE, Cadarache, BP3, 13115, Saint-Paul-lez-Durance, France
| | - Cavalié Isabelle
- LECO, IRSN, PSE-ENV, SRTE, Cadarache, BP3, 13115, Saint-Paul-lez-Durance, France
| | - Ciffroy Philippe
- EDF, Division Recherche et Développement, Laboratoire National d'Hydraulique et Environnement, 6 Quai Watier, 78401, Chatou, France
| | - Alonzo Frédéric
- LECO, IRSN, PSE-ENV, SRTE, Cadarache, BP3, 13115, Saint-Paul-lez-Durance, France.
| |
Collapse
|
5
|
Ota M, Tanaka T. Importance of root uptake of 14CO 2 on 14C transfer to plants impacted by below-ground 14CH 4 release. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 201:5-18. [PMID: 30721755 DOI: 10.1016/j.jenvrad.2019.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 01/24/2019] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
14C-labelled methane (14CH4) released from deep underground radioactive waste disposal facilities can be a below-ground source of 14CO2 owing to microbial oxidation of 14CH4 to 14CO2 in soils. Environmental 14C models assume that the transfer of 14CO2 from soil to plant occurs via foliar uptake of 14CO2. Nevertheless, the importance of 14CO2 root uptake is not well understood. In the present study, below-ground transport and oxidation of 14CH4 were modeled and incorporated into an existing land-surface 14CO2 model (SOLVEG-II) to assess the relative importance of root uptake and foliar uptake on 14CO2 transfer from soil to plants. Performance of the model in calculating the below-ground dynamics of 14CH4 was validated by simulating a field experiment of 13CH4 (as a substitute for 14CH4) injection into subsoil in a wheat field in the UK. The proposed model simulation was then applied to 14C transfer in a hypothetical ecosystem impacted by continuous 14CH4 input from the water table (bottom of 1-m thick soil), which simulated continuous release of 14CH4 from a deep underground radioactive waste disposal facility. The contrast between the results obtained from the model calculation that assumed different distributions of roots (rooting depths of 11 cm, or 97 cm) and methane oxidation (characterized by e-folding depths of 5 cm, 20 cm, or 80 cm) in the soil provided insight into the relative importance of root uptake and foliar uptake pathways. In the shallowly rooted ecosystem with rooting depth of 11 cm, foliar uptake of 14CO2 was significant, accounting for 80% of the 14C accumulation (as organic 14C) in the plant (leaf compartment). By contrast, in a deeply rooted ecosystem (rooting depth of 97 cm), where the root penetrated to depths close to the water-table, more than half (63%) the 14C accumulated in the plant was transferred via the root uptake pathway. We found that 14CO2 root uptake (thus 14C accumulation in the plant) in this ecosystem depended on the distribution of methane oxidation in the soil; all 14C accumulated in the plant was transferred by the root uptake pathway when methane oxidation occurred at considerable depths (e-folding depths of 20 cm, or 80 cm) in the soil. The high level of 14CO2 root uptake was ascribed to the oxidation of added 14CH4 (i.e., production of 14CO2) in the deep part of the soil and the subsequent high level of root uptake of the deep soil-water containing 14CO2. These results indicate that 14CO2 root uptake contributes significantly to 14CO2 transfer to plants if 14CH4 oxidation occurs at great depths and roots penetrate deeply into the soil. It is recommended that current environmental 14C models must be refined to consider the importance of the root uptake pathway to ensure that dose estimates of 14CH4 release from deep underground waste disposal facilities are accurate.
Collapse
Affiliation(s)
- Masakazu Ota
- Research Group for Environmental Science, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan.
| | - Taku Tanaka
- Group P78, Laboratoire National d'Hydraulique et Environnement, Électricité de France, 6 Quai Watier, Chatou, 78401, France
| |
Collapse
|
6
|
Le Dizès S, Gonze MA. Behavior of 36Cl in agricultural soil-plant systems: A review of transfer processes and modelling approaches. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2019; 196:82-90. [PMID: 30408682 DOI: 10.1016/j.jenvrad.2018.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 10/21/2018] [Indexed: 05/25/2023]
Abstract
This article aims to review up-to-date knowledge and data acquired on 36Cl transfers to terrestrial soil-plant systems, evaluate the existing modelling approaches and identify priorities for future model improvements. This update has revealed the existence of fairly recent studies, whose results could be used for improving the modelling approaches which have been developed over the last decade. The priority areas include the consideration of the dry deposition process and the transfer of both gaseous and aerosol 36Cl to plants. The consideration of secondary processes such as the synthesis/mineralization of organochlorines and plant biomass litterfall is not recognized as a priority issue when assessing the impact of gaseous discharges. It was also identified that additional experimental studies had to be conducted to improve the understanding of the processes governing stable Cl and 36Cl dynamics in other terrestrial ecosystems (field crops, vegetables, grass) than forest environments on which most of the reported knowledge and data are reviewed.
Collapse
Affiliation(s)
- S Le Dizès
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SRTE/LR2T, Laboratoire de Recherche sur les Transferts de Radionucléides dans les écosystèmes Terrestres, CEN Cadarache, 13115, Saint-Paul-Lez-Durance, France.
| | - M A Gonze
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SEREN/LEREN, Laboratoire d'expertise et d'étude en Radioprotection des Populations et de la Radioactivité dans l'environnement, CEN Cadarache, 13115, Saint-Paul-Lez-Durance, France
| |
Collapse
|
7
|
Le Dizès S, Aulagnier C, Maro D, Rozet M, Vermorel F, Hébert D, Voiseux C, Solier L, Godinot C, Fievet B, Laguionie P, Connan O, Cazimajou O, Morillon M. The VATO project: Development and validation of a dynamic transfer model of tritium in grassland ecosystem. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 171:83-92. [PMID: 28199861 DOI: 10.1016/j.jenvrad.2016.11.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/25/2016] [Accepted: 11/25/2016] [Indexed: 06/06/2023]
Abstract
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 3H 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. In the same time, the model achieves a good compromise between easy-to-use (as it is to be used in an operational mode), explicative power and predictive accuracy in various experimental conditions. In the framework of the VATO project, the model has been tested against two-year-long in situ measurements of 3H activity concentration monitored by IRSN in air, groundwater and grass, together with meteorological parameters, on a grass field plot located 2 km downwind of the AREVA NC La Hague nuclear reprocessing plant, as was done in the past for the evaluation of transfer of 14C in grass. By considering fast exchanges at the vegetation-air canopy interface, the model correctly reproduces the observed variability in TFWT activity concentration in grass, which evolves in accordance with spikes in atmospheric HTO activity concentration over the previous 24 h. The average OBT activity concentration in grass is also correctly reproduced. However, the model has to be improved in order to reproduce punctual high concentration of OBT activity, as observed in December 2013. The introduction of another compartment with a fast kinetic (like TFWT) - although outside the model scope - improves the predictions by increasing the correlation coefficient from 0.29 up to 0.56 when it includes this particular point. Further experimental investigation will be undertaken by IRSN and EDF next year to better evaluate (and properly model) other aspects of tritium transfer where knowledge gaps have been identified in both experimental and modelling areas.
Collapse
Affiliation(s)
- S Le Dizès
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRTE, Laboratoire de Recherche sur les Transferts de radionucléides dans l'Environnement, CEN Cadarache, 13115 Saint-Paul-Lez-Durance, France.
| | - C Aulagnier
- Electricité de France, DIPDE, 154 Avenue Thiers, 69458 Lyon, Cedex 06 France
| | - D Maro
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - M Rozet
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - F Vermorel
- Electricité de France, DIPDE, 154 Avenue Thiers, 69458 Lyon, Cedex 06 France
| | - D Hébert
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - C Voiseux
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - L Solier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - C Godinot
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - B Fievet
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - P Laguionie
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - O Connan
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - O Cazimajou
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| | - M Morillon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Rue Max-Pol Fouchet B.P.10, 50130 Cherbourg-Octeville, France
| |
Collapse
|
8
|
Dizès SL, Maro D, Rozet M, Hébert D. Modeling and Validating Tritium Transfer in a Grassland Ecosystem in Response to3h Releases. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst14-t51] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Séverine Le Dizès
- Institute for Radioprotection and Nuclear Safety, IRSN/PRP-ENV/SERIS/LM2E. CE Cadarache Bât.159. BP3 13115 Saint-Paul-lez-Durance Cedex, France
| | - Denis Maro
- IRSN/PRP-ENV/SERIS/LRC. BP 10, F-50130 Cherbourg-Octeville, France
| | - Marianne Rozet
- IRSN/PRP-ENV/SERIS/LRC. BP 10, F-50130 Cherbourg-Octeville, France
| | - Didier Hébert
- IRSN/PRP-ENV/SERIS/LRC. BP 10, F-50130 Cherbourg-Octeville, France
| |
Collapse
|
9
|
Maro D, Vermorel F, Rozet M, Aulagnier C, Hébert D, Le Dizès S, Voiseux C, Solier L, Cossonnet C, Godinot C, Fiévet B, Laguionie P, Connan O, Cazimajou O, Morillon M, Lamotte M. The VATO project: An original methodology to study the transfer of tritium as HT and HTO in grassland ecosystem. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2017; 167:235-248. [PMID: 27908461 DOI: 10.1016/j.jenvrad.2016.10.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/27/2016] [Accepted: 10/27/2016] [Indexed: 06/06/2023]
Abstract
Tritium (3H) 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 3H 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 3H from an atmospheric source (currently releasing HT and HTO) to a grassland ecosystem. A fully instrumented technical platform with specifically designed materials was set up downwind of the AREVA NC La Hague reprocessing plant (Northwest of the France). This study, started in 2013, was conducted in four main steps to provide an hourly data set of 3H concentrations in the environment, adequate to develop and/or validate transfer models. It consisted first in characterizing the physico-chemical forms of 3H present in the air around the plant. Then, 3H transfer kinetics to grass were quantified regarding contributions from various compartments of the environment. For this purpose, an original experimental procedure was provided to take account for biases due to rehydration of freeze-dried samples for the determination of OBT activity concentrations in biological samples. In a third step, the 3H concentrations measured in the air and in rainwater were reconstructed at hourly intervals. Finally, a data processing technique was used to determine the biological half-lives of OBT in grass.
Collapse
Affiliation(s)
- D Maro
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France.
| | - F Vermorel
- Electricité de France, DIPDE, Lyon, 69458, France
| | - M Rozet
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - C Aulagnier
- Electricité de France, DIPDE, Lyon, 69458, France
| | - D Hébert
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - S Le Dizès
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRTE, Laboratoire de Recherche sur les Transferts des Radionucléides dans l'Environnement, CEN Cadarache, Saint Paul Lez Durance, 13115, France
| | - C Voiseux
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - L Solier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - C Cossonnet
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/STEME/LMRE, Laboratoire de Mesure de la Radioactivité dans l'Environnement, Bois des Rames, Orsay, 91400, France
| | - C Godinot
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - B Fiévet
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - P Laguionie
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - O Connan
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - O Cazimajou
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - M Morillon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| | - M Lamotte
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville, 50130, France
| |
Collapse
|
10
|
Ota M, Katata G, Nagai H, Terada H. Impacts of C-uptake by plants on the spatial distribution of 14C accumulated in vegetation around a nuclear facility-Application of a sophisticated land surface 14C model to the Rokkasho reprocessing plant, Japan. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 162-163:189-204. [PMID: 27267157 DOI: 10.1016/j.jenvrad.2016.05.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/24/2016] [Accepted: 05/29/2016] [Indexed: 06/06/2023]
Abstract
The impacts of carbon uptake by plants on the spatial distribution of radiocarbon (14C) accumulated in vegetation around a nuclear facility were investigated by numerical simulations using a sophisticated land surface 14C model (SOLVEG-II). In the simulation, SOLVEG-II was combined with a mesoscale meteorological model and an atmospheric dispersion model. The model combination was applied to simulate the transfer of 14CO2 and to assess the radiological impact of 14C accumulation in rice grains during test operations of the Rokkasho reprocessing plant (RRP), Japan, in 2007. The calculated 14C-specific activities in rice grains agreed with the observed activities in paddy fields around the RRP within a factor of four. The annual effective dose delivered from 14C in the rice grain was estimated to be less than 0.7 μSv, only 0.07% of the annual effective dose limit of 1 mSv for the public. Numerical experiments of hypothetical continuous atmospheric 14CO2 release from the RRP showed that the 14C-specific activities of rice plants at harvest differed from the annual mean activities in the air. The difference was attributed to seasonal variations in the atmospheric 14CO2 concentration and the growth of the rice plant. Accumulation of 14C in the rice plant significantly increased when 14CO2 releases were limited during daytime hours, compared with the results observed during the nighttime. These results indicated that plant growth stages and diurnal photosynthesis should be considered in predictions of the ingestion dose of 14C for long-term chronic releases and short-term diurnal releases of 14CO2, respectively.
Collapse
Affiliation(s)
- Masakazu Ota
- Research Group for Environmental Science, Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan.
| | - Genki Katata
- Research Group for Environmental Science, Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Haruyasu Nagai
- Research Group for Environmental Science, Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - Hiroaki Terada
- Research Group for Environmental Science, Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| |
Collapse
|
11
|
Mihok S, Wilk M, Lapp A, St-Amant N, Kwamena NOA, Clark ID. Tritium dynamics in soils and plants grown under three irrigation regimes at a tritium processing facility in Canada. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 153:176-187. [PMID: 26773512 DOI: 10.1016/j.jenvrad.2015.12.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 12/27/2015] [Accepted: 12/28/2015] [Indexed: 06/05/2023]
Abstract
The dynamics of tritium released from nuclear facilities as tritiated water (HTO) have been studied extensively with results incorporated into regulatory assessment models. These models typically estimate organically bound tritium (OBT) for calculating public dose as OBT itself is rarely measured. Higher than expected OBT/HTO ratios in plants and soils are an emerging issue that is not well understood. To support the improvement of models, an experimental garden was set up in 2012 at a tritium processing facility in Pembroke, Ontario to characterize the circumstances under which high OBT/HTO ratios may arise. Soils and plants were sampled weekly to coincide with detailed air and stack monitoring. The design included a plot of native grass/soil, contrasted with sod and vegetables grown in barrels with commercial topsoil under natural rain and either low or high tritium irrigation water. Air monitoring indicated that the plume was present infrequently at concentrations of up to about 100 Bq/m(3) (the garden was not in a major wind sector). Mean air concentrations during the day on workdays (HTO 10.3 Bq/m(3), HT 5.8 Bq/m(3)) were higher than at other times (0.7-2.6 Bq/m(3)). Mean Tissue Free Water Tritium (TFWT) in plants and soils and OBT/HTO ratios were only very weakly or not at all correlated with releases on a weekly basis. TFWT was equal in soils and plants and in above and below ground parts of vegetables. OBT/HTO ratios in above ground parts of vegetables were above one when the main source of tritium was from high tritium irrigation water (1.5-1.8). Ratios were below one in below ground parts of vegetables when irrigated with high tritium water (0.4-0.6) and above one in vegetables rain-fed or irrigated with low tritium water (1.3-2.8). In contrast, OBT/HTO ratios were very high (9.0-13.5) when the source of tritium was mainly from the atmosphere. TFWT varied considerably through time as a result of SRBT's operations; OBT/HTO ratios showed no clear temporal pattern in above or below ground plant parts. Native soil after ∼20 years of operations at SRBT had high initial OBT that persisted through the growing season; little OBT formed in garden plot soil during experiments. High OBT in native soil appeared to be a signature of higher past releases at SRBT. This phenomenon was confirmed in soils obtained at another processing facility in Canada with a similar history. The insights into variation in OBT/HTO ratios found here are of regulatory interest and should be incorporated in assessment models to aid in the design of relevant environmental monitoring programs for OBT.
Collapse
Affiliation(s)
- S Mihok
- Canadian Nuclear Safety Commission, 280 Slater Street, P.O. Box 1046, Station B, Ottawa, Ontario K1P 5S9, Canada.
| | - M Wilk
- Department of Earth Sciences, 140 Louis-Pasteur, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - A Lapp
- Department of Earth Sciences, 140 Louis-Pasteur, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - N St-Amant
- Canadian Nuclear Safety Commission, 280 Slater Street, P.O. Box 1046, Station B, Ottawa, Ontario K1P 5S9, Canada
| | - N-O A Kwamena
- Canadian Nuclear Safety Commission, 280 Slater Street, P.O. Box 1046, Station B, Ottawa, Ontario K1P 5S9, Canada
| | - I D Clark
- Department of Earth Sciences, 140 Louis-Pasteur, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| |
Collapse
|
12
|
Connan O, Maro D, Hébert D, Solier L, Caldeira Ideas P, Laguionie P, St-Amant N. 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. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2015; 148:1-9. [PMID: 26091609 DOI: 10.1016/j.jenvrad.2015.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/01/2015] [Accepted: 06/06/2015] [Indexed: 06/04/2023]
Abstract
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. The results show that each of the three methods gave similar results. The various constraints applying to each method are discussed. The results show a tritium evapotranspiration flux of around 15 mBq m(-2) s(-1) in this environment. These results will be used to improve the entry parameters for the general models of tritium transfers in the environment.
Collapse
Affiliation(s)
- O Connan
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville 50130, France.
| | - D Maro
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville 50130, France
| | - D Hébert
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville 50130, France
| | - L Solier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville 50130, France
| | - P Caldeira Ideas
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), IPRP-ENV/SESURE/LS3E, Laboratoire de Surveillance et d'Expertise Environnementale par Echantillonnage, Le Vésinet 78116, France
| | - P Laguionie
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LRC, Laboratoire de Radioécologie de Cherbourg Octeville, Cherbourg-Octeville 50130, France
| | - N St-Amant
- Canadian Nuclear Safety Commission, Ottawa, Canada
| |
Collapse
|
13
|
Limer LMC, Le Dizès-Maurel S, Klos R, Maro D, Nordén M. 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. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2015; 147:115-124. [PMID: 26063400 DOI: 10.1016/j.jenvrad.2015.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 05/06/2015] [Accepted: 05/15/2015] [Indexed: 06/04/2023]
Abstract
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. These models have been applied here to the La Hague field data as it represents a medium term data set with both short term variation and a sizeable time series of measurements against which to compare the models. The two models have different objectives in terms of the timescales they are intended to be applied over, and thus incorporate biological processes, such as photosynthesis and plant growth, at different levels of complexity. It was found that the inclusion of seasonal dynamics in the models improved predictions of the specific activity in grass for such a source term of atmospheric (14)C.
Collapse
Affiliation(s)
- Laura M C Limer
- Quintessa Limited, 633/635 Birchwood Boulevard, WA3 7QU, Warrington, United Kingdom.
| | - Séverine Le Dizès-Maurel
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, Saint-Paul Lez Durance, France
| | - Ryk Klos
- Aleksandria Sciences Limited, S7 2DD, Sheffield, United Kingdom
| | - Denis Maro
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, Saint-Paul Lez Durance, France
| | - Maria Nordén
- Swedish Radiation Safety Authority, SE-171 16, Stockholm, Sweden
| |
Collapse
|
14
|
Simon-Cornu M, Beaugelin-Seiller K, Boyer P, Calmon P, Garcia-Sanchez L, Mourlon C, Nicoulaud V, Sy M, Gonze MA. Evaluating variability and uncertainty in radiological impact assessment using SYMBIOSE. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2015; 139:91-102. [PMID: 25464045 DOI: 10.1016/j.jenvrad.2014.09.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 09/09/2014] [Accepted: 09/22/2014] [Indexed: 06/04/2023]
Abstract
SYMBIOSE is a modelling platform that accounts for variability and uncertainty in radiological impact assessments, when simulating the environmental fate of radionuclides and assessing doses to human populations. The default database of SYMBIOSE is partly based on parameter values that are summarized within International Atomic Energy Agency (IAEA) documents. To characterize uncertainty on the transfer parameters, 331 Probability Distribution Functions (PDFs) were defined from the summary statistics provided within the IAEA documents (i.e. sample size, minimal and maximum values, arithmetic and geometric means, standard and geometric standard deviations) and are made available as spreadsheet files. The methods used to derive the PDFs without complete data sets, but merely the summary statistics, are presented. Then, a simple case-study illustrates the use of the database in a second-order Monte Carlo calculation, separating parametric uncertainty and inter-individual variability.
Collapse
Affiliation(s)
- M Simon-Cornu
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, France.
| | - K Beaugelin-Seiller
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, France
| | - P Boyer
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, France
| | - P Calmon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SESURE, LERCM, Cadarache, France
| | - L Garcia-Sanchez
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, L2BT, Cadarache, France
| | - C Mourlon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, France
| | - V Nicoulaud
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, France
| | - M Sy
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, France
| | - M A Gonze
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, France
| |
Collapse
|
15
|
Le Dizès S, Aulagnier C, Henner P, Simon-Cornu M. TOCATTA: a dynamic transfer model of (3)H from the atmosphere to soil-plant systems. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 124:191-204. [PMID: 23811129 DOI: 10.1016/j.jenvrad.2013.04.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 03/22/2013] [Accepted: 04/22/2013] [Indexed: 06/02/2023]
Abstract
This paper describes a dynamic compartment model (TOCATTA) that simulates tritium transfer in agricultural plants of several categories including vegetables, pasture and annual crops, exposed to time-varying HTO concentrations of water vapour in the air and possibly in irrigation and rainwater. Consideration is also given to the transfer pathways of HTO in soil. Though the transfer of tritium is quite complex, from its release into the environment to its absorption and its incorporation within the organic material of living organisms, the TOCATTA model is relatively simple, with a limited number of compartments and input parameters appropriate to its use in an operational mode. In this paper, we took the opportunity to have data obtained on an ornamental plant - an indoor palm tree - within an industrial building where tritium was released accidentally over several weeks (or months). More specifically, the model's ability to provide hindsight on the chronology of the release scenario is discussed by comparing model predictions of TFWT and OBT activity concentrations in the plant leaves with measurements performed on three different leaves characterized by different developmental stages. The data-model comparison shows some limitations, mainly because of a lack of knowledge about the initial conditions of the accident and when it actually started and about the processes involved in the transfer of tritium. Efforts are needed in both experimental and modelling areas for future evaluation of tritium behaviour in agricultural soil and plants exposed to gaseous HTO releases and/or to irrigation with contaminated water.
Collapse
Affiliation(s)
- S Le Dizès
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, 13015 Cadarache, France.
| | | | | | | |
Collapse
|
16
|
Aulagnier C, Le Dizès S, Maro D, Hébert D, Lardy R, Martin R. The TOCATTA-χ model for assessing 14C transfers to grass: an evaluation for atmospheric operational releases from nuclear facilities. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 120:81-93. [PMID: 23466654 DOI: 10.1016/j.jenvrad.2012.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 12/10/2012] [Accepted: 12/20/2012] [Indexed: 06/01/2023]
Abstract
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. The TOCATTA-χ model has been tested against observations of (14)C activity concentrations in grass samples collected monthly from six plots which are located around the periphery of the reprocessing plant. Simulated (14)C activities are consistent with observations on both intensively managed and poorly managed grasslands, but an adaptation of the mean turn-over time for (14)C within the plant is necessary in the model to account for different management practices. When atmospheric (14)C activity concentrations are directly inferred from observations, TOCATTA-χ performs better than TOCATTA (the root mean square error is decreased by 45%), but when atmospheric (14)C activity concentrations are not known and must be calculated, the uncertainty associated with the TOCATTA-χ model outcomes is estimated to be larger than the standard deviation of the observations.
Collapse
Affiliation(s)
- Céline Aulagnier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, 13115 Cadarache, France
| | | | | | | | | | | |
Collapse
|
17
|
Melintescu A, Galeriu D, Tucker S, Kennedy P, Siclet F, Yamamoto K, Uchida S. Carbon-14 transfer into potato plants following a short exposure to an atmospheric 14CO2 emission: observations and model predictions. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 115:183-191. [PMID: 22995861 DOI: 10.1016/j.jenvrad.2012.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 05/31/2012] [Accepted: 08/06/2012] [Indexed: 06/01/2023]
Abstract
To improve the understanding of the environmental (14)C behaviour, the International Atomic Energy Agency (IAEA) coordinated a Tritium and C-14 Working Group (T&C WG) in its EMRAS (Environmental Modelling for Radiation Safety) programme. One of the scenarios developed in the frame of T&C WG involved the prediction of time dependent (14)C concentrations in potato plants. The experimental data used in the scenario were obtained from a study in which potatoes (Solanum tuberosum cv. Romano) were exposed to atmospheric (14)CO(2) in a wind tunnel. The observations were used to test models that predict temporal changes in (14)C concentrations in leaves at each sampling time for each experiment and (14)C concentrations in tubers at the final harvest of each experiment. The experimental data on (14)C dynamics in leaves are poorly reproduced by most of the models, but the predicted concentrations in tubers are in good agreement with the observations.
Collapse
Affiliation(s)
- A Melintescu
- Departemt of Life and Environmental Physics, "Horia Hulubei" National Institute of Physics and Nuclear Engineering, Magurele, Romania.
| | | | | | | | | | | | | |
Collapse
|
18
|
Aulagnier C, Le Dizès S, Maro D, Hébert D, Lardy R, Martin R, Gonze MA. Modelling the transfer of 14C from the atmosphere to grass: a case study in a grass field near AREVA-NC La Hague. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2012; 112:52-59. [PMID: 22537618 DOI: 10.1016/j.jenvrad.2012.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 01/30/2012] [Accepted: 03/30/2012] [Indexed: 05/31/2023]
Abstract
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. 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. These two models are the TOCATTA model which is specifically designed for modelling transfer of (14)C and tritium in the terrestrial environment, and PaSim, a pasture model for simulating grassland carbon and nitrogen cycling. Both TOCATTA and PaSim tend to under-estimate the magnitude of observed peaks in grass (14)C activity, although they reproduce the general trends. PaSim simulates (14)C activities in substrate and structural pools of the plant. We define a mean turn-over time for (14)C within the plant, which is based on both experimental data and the frequency of cuts. An adapted PaSim result is presented using the 15 and 20 day moving average results for the (14)C activity in the substrate pool, which shows a good match to the observations. This model reduces the Root Mean Square Error (RMSE) by nearly 40% in comparison to TOCATTA.
Collapse
Affiliation(s)
- C Aulagnier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV, SERIS, LM2E, Cadarache, Saint-Paul Lez Durance, France.
| | | | | | | | | | | | | |
Collapse
|