{"id":7084,"date":"2024-11-12T08:50:25","date_gmt":"2024-11-12T07:50:25","guid":{"rendered":"https:\/\/ingenius.ecoledesponts.fr\/?p=7084"},"modified":"2025-07-29T16:23:21","modified_gmt":"2025-07-29T14:23:21","slug":"identifying-and-quantifying-radioactive-substance-emissions-in-the-atmosphere","status":"publish","type":"post","link":"https:\/\/ingenius.ecoledesponts.fr\/en\/articles\/identifying-and-quantifying-radioactive-substance-emissions-in-the-atmosphere\/","title":{"rendered":"Identifying and quantifying radioactive substance emissions in the atmosphere\u00a0"},"content":{"rendered":"\n\n\n
\"\"
Map of a simulated radioactive released from the Fukushima nuclear accident in March 2011. Credit: Cerea.<\/figcaption><\/figure>\n\n\n\n

The nuclear industry, like many industrial activities, produces discharges into the environment. Radioactive discharge management is a major issue to secure facilities and protect the environment. These discharges are strictly controlled before, during and after their emission, in accordance with regulatory limits set by ASN (Autorit\u00e9 de S\u00fbret\u00e9 Nucl\u00e9aire<\/em>, French Nuclear Safety Authority).<\/p>\n\n\n\n

In the case of accidental discharge into the environment, identification and characterization of atmospheric releases of radioactive substances, called radionuclides, form an integral part of the strategy to prevent and manage risks associated with the nuclear industry.<\/p>\n\n\n\n

Modeling to protect<\/h2>\n\n\n\n

It is essential to have precise information on the accidental release, such as its intensity, the location of its source, and the physicochemical nature of the radioactive elements involved. This data is crucial to drive numerical models enabling prediction of the evolution of concentrations of radionuclides in the air as well as the quantity of radioactivity deposited on the ground.<\/p>\n\n\n\n

The results of these models are used to determine any zones to be evacuated in order to protect populations in the event of a major accident. In addition, once the discharges have ended, this same approach based on modeling can be supplemented with in-field sampling. This allows better identification of affected geographical zones and accordingly definition of use restrictions, such as prohibiting consumption of agricultural products. In some cases, there can also be plans to implement exclusion zones.<\/p>\n\n\n\n

Monitoring and modeling of the operation of nuclear facilities, including in the event of an accident, allow to assess the characteristics of a (possibly accidental) discharge of radionuclides into the atmosphere. However, these estimations often feature significant uncertainties, as was demonstrated in the event of the Fukushima accident. Automated environmental monitoring networks combined with the deployment of mobile in-field systems1<\/a><\/sup> accordingly facilitate the rapid detection of any unusual rise in ambient radioactivity and consequently the sharing of additional information.<\/p>\n\n\n\n

Numerical models that simulate the dispersion of radionuclides elucidate the link between the discharge and the measurements. Combining environmental measurements with the results of these models enables the reconstruction of the characteristics of a discharge.<\/p>\n\n\n\n

This approach, which is based on data assimilation <\/em>methods, is called inverse modeling of the source term<\/em><\/a>. In collaboration with IRSN, CEREA has been working for more than 20 years on implementing this type of techniques and is among the cutting-edge international teams in this field.<\/p>\n\n\n\n

Fukushima accident case study<\/h2>\n\n\n\n

Following the Fukushima accident in March 2011, a massive amount of radionuclides was emitted into the environment due to the fusion of the cores of several reactors. The changing weather during the accident combined with Japan\u2019s complex topography made it particularly difficult to precisely estimate the discharges. The release, spread over a 3-week period and were highly variable in terms of the amplitude and nature of radionuclides emitted.<\/p>\n\n\n\n

Faced with these challenges, the work done by CEREA in collaboration with IRSN served to bolster inverse modeling<\/em> techniques based on a probabilistic method. It aims to quantify the characteristics of the discharge but also the uncertainties inherent in their assessment. The most probable values for the characteristics of the emissions were estimated, such as the total released radioactivity, together with their corresponding uncertainty.<\/p>\n\n\n\n

The new method developed enables automatic adjustment of the temporal resolution of the description of the source term (its discretization) based on information from observations. It therefore facilitates the processing of the high temporal dynamic of long-term discharges.<\/p>\n\n\n\n

\"\"
Evolution of the release rate (Bq\/s) reconstructed by inverse modeling with the \u201creversible jump\u201d algorithm (RJ-MCMC, in blue) compared with other reconstructions proposed in the scientific literature (in green and pink). The shaded area corresponds to the estimated uncertainties associated with the release rate (Source<\/a>)<\/figcaption><\/figure>\n\n\n\n

The results obtained by this method show that the total quantity of radioactivity discharged into the atmosphere in the course of the Fukushima accident due to caesium-137would be between 10 to 20 Petabecquerels (PBq), with a most probable estimate of approximately 14 PBq, matching other studies [Saunier et al., 2013<\/a>, Terada et al., 2020<\/a>]. For comparison, the quantity of radioactivity of this radionuclide released during the Chernobyl accident was estimated to be 85 PBq.<\/p>\n\n\n\n

\n
\n
\"\"
Evolution of the average number of steps used each day to describe the temporal dynamics of rejection (red curve) and associated uncertainties (red area) (Author provided ).<\/figcaption><\/figure>\n<\/div>\n\n\n\n
\n
\"\"
Probability density associated with the amount of total radioactivity released in March 2011 (Author provided).<\/figcaption><\/figure>\n<\/div>\n<\/div>\n\n\n\n

Finally, this approach, thanks to a reasonable computation time, can be used for other accidental situations. It was recently successfully applied to low-amplitude discharge events, such as forest fires in Ukraine and the detection of radionuclides in northern Europe in 2020.<\/p>\n\n\n\n

<\/p>\n\n\n

  1. In France, the Teleray network (https:\/\/www.irsn.fr\/savoir-comprendre\/environnement\/reseaux-telesurveillance<\/a>) operated by the Institute for Radiological Protection and Nuclear Safety (IRSN) is used for daily monitoring of the territory \u21a9\ufe0e<\/a><\/li><\/ol>\n\n\n
    \n

    thesis Joffrey Dumont Le Brazidec<\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    The nuclear industry, like many industrial activities, produces discharges into the environment. Radioactive discharge management is a major issue to […]<\/p>\n","protected":false},"author":9,"featured_media":7191,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_related_content_post":[],"_related_content_subject":[937,690],"_related_content_author":[6709,6720,7186,7197],"_related_content_category":[1716,1720],"_related_content_folder":[6913],"_excerpt":"The nuclear industry generates radioactive discharges that require rigorous management to secure facilities and protect the environment. This article demonstrates the benefits of numerical modeling to predict and quantify discharges and their impacts, taking the accident that occurred at the Fukushima power plant as a case study.","_duration":4,"_manual_duration":false,"footnotes":"[{\"content\":\"In France, the Teleray network (https:\/\/www.irsn.fr\/savoir-comprendre\/environnement\/reseaux-telesurveillance<\/a>) operated by the Institute for Radiological Protection and Nuclear Safety (IRSN) is used for daily monitoring of the territory\",\"id\":\"77879839-9d50-476d-a7ca-27bc52f257e7\"}]"},"article-types":[13,27],"class_list":["post-7084","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","article-types-article","article-types-folder"],"has_blocks":true,"block_data":[{"blockName":"enpc\/excerpt","attrs":{"lock":[],"metadata":[],"className":"","style":""},"innerBlocks":[],"innerHTML":"","innerContent":[],"rendered":""},{"blockName":"core\/image","attrs":{"id":7191,"sizeSlug":"large","linkDestination":"none","align":"wide","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/Fukushima-simulated-plume-1024x248.png","alt":"","caption":"Map of a simulated radioactive released from the Fukushima nuclear accident in March 2011. Credit: Cerea.","lightbox":[],"title":"","href":"","rel":"","linkClass":"","width":"","height":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"className":"wp-block-image alignwide size-large","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    \"\"
    Map of a simulated radioactive released from the Fukushima nuclear accident in March 2011. Credit: Cerea.<\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Map of a simulated radioactive released from the Fukushima nuclear accident in March 2011. Credit: Cerea.<\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Map of a simulated radioactive released from the Fukushima nuclear accident in March 2011. Credit: Cerea.<\/figcaption><\/figure>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"The nuclear industry, like many industrial activities, produces discharges into the environment. Radioactive discharge management is a major issue to secure facilities and protect the environment. These discharges are strictly controlled before, during and after their emission, in accordance with regulatory limits set by ASN (Autorit\u00e9 de S\u00fbret\u00e9 Nucl\u00e9aire, French Nuclear Safety Authority).","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    The nuclear industry, like many industrial activities, produces discharges into the environment. Radioactive discharge management is a major issue to secure facilities and protect the environment. These discharges are strictly controlled before, during and after their emission, in accordance with regulatory limits set by ASN (Autorit\u00e9 de S\u00fbret\u00e9 Nucl\u00e9aire<\/em>, French Nuclear Safety Authority).<\/p>\n","innerContent":["\n

    The nuclear industry, like many industrial activities, produces discharges into the environment. Radioactive discharge management is a major issue to secure facilities and protect the environment. These discharges are strictly controlled before, during and after their emission, in accordance with regulatory limits set by ASN (Autorit\u00e9 de S\u00fbret\u00e9 Nucl\u00e9aire<\/em>, French Nuclear Safety Authority).<\/p>\n"],"rendered":"\n

    The nuclear industry, like many industrial activities, produces discharges into the environment. Radioactive discharge management is a major issue to secure facilities and protect the environment. These discharges are strictly controlled before, during and after their emission, in accordance with regulatory limits set by ASN (Autorit\u00e9 de S\u00fbret\u00e9 Nucl\u00e9aire<\/em>, French Nuclear Safety Authority).<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"In the case of accidental discharge into the environment, identification and characterization of atmospheric releases of radioactive substances, called radionuclides, form an integral part of the strategy to prevent and manage risks associated with the nuclear industry.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    In the case of accidental discharge into the environment, identification and characterization of atmospheric releases of radioactive substances, called radionuclides, form an integral part of the strategy to prevent and manage risks associated with the nuclear industry.<\/p>\n","innerContent":["\n

    In the case of accidental discharge into the environment, identification and characterization of atmospheric releases of radioactive substances, called radionuclides, form an integral part of the strategy to prevent and manage risks associated with the nuclear industry.<\/p>\n"],"rendered":"\n

    In the case of accidental discharge into the environment, identification and characterization of atmospheric releases of radioactive substances, called radionuclides, form an integral part of the strategy to prevent and manage risks associated with the nuclear industry.<\/p>\n"},{"blockName":"core\/heading","attrs":{"style":{"elements":{"link":{"color":{"text":"var:preset|color|red"}}}},"textColor":"red","textAlign":"","content":"Modeling to protect","level":2,"levelOptions":[],"placeholder":"","lock":[],"metadata":[],"align":"","className":"wp-block-heading has-red-color has-text-color has-link-color","backgroundColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Modeling to protect<\/h2>\n","innerContent":["\n

    Modeling to protect<\/h2>\n"],"rendered":"\n

    Modeling to protect<\/h2>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"It is essential to have precise information on the accidental release, such as its intensity, the location of its source, and the physicochemical nature of the radioactive elements involved. This data is crucial to drive numerical models enabling prediction of the evolution of concentrations of radionuclides in the air as well as the quantity of radioactivity deposited on the ground.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    It is essential to have precise information on the accidental release, such as its intensity, the location of its source, and the physicochemical nature of the radioactive elements involved. This data is crucial to drive numerical models enabling prediction of the evolution of concentrations of radionuclides in the air as well as the quantity of radioactivity deposited on the ground.<\/p>\n","innerContent":["\n

    It is essential to have precise information on the accidental release, such as its intensity, the location of its source, and the physicochemical nature of the radioactive elements involved. This data is crucial to drive numerical models enabling prediction of the evolution of concentrations of radionuclides in the air as well as the quantity of radioactivity deposited on the ground.<\/p>\n"],"rendered":"\n

    It is essential to have precise information on the accidental release, such as its intensity, the location of its source, and the physicochemical nature of the radioactive elements involved. This data is crucial to drive numerical models enabling prediction of the evolution of concentrations of radionuclides in the air as well as the quantity of radioactivity deposited on the ground.<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"The results of these models are used to determine any zones to be evacuated in order to protect populations in the event of a major accident. In addition, once the discharges have ended, this same approach based on modeling can be supplemented with in-field sampling. This allows better identification of affected geographical zones and accordingly definition of use restrictions, such as prohibiting consumption of agricultural products. In some cases, there can also be plans to implement exclusion zones.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    The results of these models are used to determine any zones to be evacuated in order to protect populations in the event of a major accident. In addition, once the discharges have ended, this same approach based on modeling can be supplemented with in-field sampling. This allows better identification of affected geographical zones and accordingly definition of use restrictions, such as prohibiting consumption of agricultural products. In some cases, there can also be plans to implement exclusion zones.<\/p>\n","innerContent":["\n

    The results of these models are used to determine any zones to be evacuated in order to protect populations in the event of a major accident. In addition, once the discharges have ended, this same approach based on modeling can be supplemented with in-field sampling. This allows better identification of affected geographical zones and accordingly definition of use restrictions, such as prohibiting consumption of agricultural products. In some cases, there can also be plans to implement exclusion zones.<\/p>\n"],"rendered":"\n

    The results of these models are used to determine any zones to be evacuated in order to protect populations in the event of a major accident. In addition, once the discharges have ended, this same approach based on modeling can be supplemented with in-field sampling. This allows better identification of affected geographical zones and accordingly definition of use restrictions, such as prohibiting consumption of agricultural products. In some cases, there can also be plans to implement exclusion zones.<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"Monitoring and modeling of the operation of nuclear facilities, including in the event of an accident, allow to assess the characteristics of a (possibly accidental) discharge of radionuclides into the atmosphere. However, these estimations often feature significant uncertainties, as was demonstrated in the event of the Fukushima accident. Automated environmental monitoring networks combined with the deployment of mobile in-field systems1 accordingly facilitate the rapid detection of any unusual rise in ambient radioactivity and consequently the sharing of additional information.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Monitoring and modeling of the operation of nuclear facilities, including in the event of an accident, allow to assess the characteristics of a (possibly accidental) discharge of radionuclides into the atmosphere. However, these estimations often feature significant uncertainties, as was demonstrated in the event of the Fukushima accident. Automated environmental monitoring networks combined with the deployment of mobile in-field systems1<\/a><\/sup> accordingly facilitate the rapid detection of any unusual rise in ambient radioactivity and consequently the sharing of additional information.<\/p>\n","innerContent":["\n

    Monitoring and modeling of the operation of nuclear facilities, including in the event of an accident, allow to assess the characteristics of a (possibly accidental) discharge of radionuclides into the atmosphere. However, these estimations often feature significant uncertainties, as was demonstrated in the event of the Fukushima accident. Automated environmental monitoring networks combined with the deployment of mobile in-field systems1<\/a><\/sup> accordingly facilitate the rapid detection of any unusual rise in ambient radioactivity and consequently the sharing of additional information.<\/p>\n"],"rendered":"\n

    Monitoring and modeling of the operation of nuclear facilities, including in the event of an accident, allow to assess the characteristics of a (possibly accidental) discharge of radionuclides into the atmosphere. However, these estimations often feature significant uncertainties, as was demonstrated in the event of the Fukushima accident. Automated environmental monitoring networks combined with the deployment of mobile in-field systems1<\/a><\/sup> accordingly facilitate the rapid detection of any unusual rise in ambient radioactivity and consequently the sharing of additional information.<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"Numerical models that simulate the dispersion of radionuclides elucidate the link between the discharge and the measurements. Combining environmental measurements with the results of these models enables the reconstruction of the characteristics of a discharge.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Numerical models that simulate the dispersion of radionuclides elucidate the link between the discharge and the measurements. Combining environmental measurements with the results of these models enables the reconstruction of the characteristics of a discharge.<\/p>\n","innerContent":["\n

    Numerical models that simulate the dispersion of radionuclides elucidate the link between the discharge and the measurements. Combining environmental measurements with the results of these models enables the reconstruction of the characteristics of a discharge.<\/p>\n"],"rendered":"\n

    Numerical models that simulate the dispersion of radionuclides elucidate the link between the discharge and the measurements. Combining environmental measurements with the results of these models enables the reconstruction of the characteristics of a discharge.<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"This approach, which is based on data assimilation methods, is called inverse modeling of the source term. In collaboration with IRSN, CEREA has been working for more than 20 years on implementing this type of techniques and is among the cutting-edge international teams in this field.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    This approach, which is based on data assimilation <\/em>methods, is called inverse modeling of the source term<\/em><\/a>. In collaboration with IRSN, CEREA has been working for more than 20 years on implementing this type of techniques and is among the cutting-edge international teams in this field.<\/p>\n","innerContent":["\n

    This approach, which is based on data assimilation <\/em>methods, is called inverse modeling of the source term<\/em><\/a>. In collaboration with IRSN, CEREA has been working for more than 20 years on implementing this type of techniques and is among the cutting-edge international teams in this field.<\/p>\n"],"rendered":"\n

    This approach, which is based on data assimilation <\/em>methods, is called inverse modeling of the source term<\/em><\/a>. In collaboration with IRSN, CEREA has been working for more than 20 years on implementing this type of techniques and is among the cutting-edge international teams in this field.<\/p>\n"},{"blockName":"core\/heading","attrs":{"style":{"elements":{"link":{"color":{"text":"var:preset|color|red"}}}},"textColor":"red","textAlign":"","content":"Fukushima accident case study","level":2,"levelOptions":[],"placeholder":"","lock":[],"metadata":[],"align":"","className":"wp-block-heading has-red-color has-text-color has-link-color","backgroundColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Fukushima accident case study<\/h2>\n","innerContent":["\n

    Fukushima accident case study<\/h2>\n"],"rendered":"\n

    Fukushima accident case study<\/h2>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"Following the Fukushima accident in March 2011, a massive amount of radionuclides was emitted into the environment due to the fusion of the cores of several reactors. The changing weather during the accident combined with Japan\u2019s complex topography made it particularly difficult to precisely estimate the discharges. The release, spread over a 3-week period and were highly variable in terms of the amplitude and nature of radionuclides emitted.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Following the Fukushima accident in March 2011, a massive amount of radionuclides was emitted into the environment due to the fusion of the cores of several reactors. The changing weather during the accident combined with Japan\u2019s complex topography made it particularly difficult to precisely estimate the discharges. The release, spread over a 3-week period and were highly variable in terms of the amplitude and nature of radionuclides emitted.<\/p>\n","innerContent":["\n

    Following the Fukushima accident in March 2011, a massive amount of radionuclides was emitted into the environment due to the fusion of the cores of several reactors. The changing weather during the accident combined with Japan\u2019s complex topography made it particularly difficult to precisely estimate the discharges. The release, spread over a 3-week period and were highly variable in terms of the amplitude and nature of radionuclides emitted.<\/p>\n"],"rendered":"\n

    Following the Fukushima accident in March 2011, a massive amount of radionuclides was emitted into the environment due to the fusion of the cores of several reactors. The changing weather during the accident combined with Japan\u2019s complex topography made it particularly difficult to precisely estimate the discharges. The release, spread over a 3-week period and were highly variable in terms of the amplitude and nature of radionuclides emitted.<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"Faced with these challenges, the work done by CEREA in collaboration with IRSN served to bolster inverse modeling techniques based on a probabilistic method. It aims to quantify the characteristics of the discharge but also the uncertainties inherent in their assessment. The most probable values for the characteristics of the emissions were estimated, such as the total released radioactivity, together with their corresponding uncertainty.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Faced with these challenges, the work done by CEREA in collaboration with IRSN served to bolster inverse modeling<\/em> techniques based on a probabilistic method. It aims to quantify the characteristics of the discharge but also the uncertainties inherent in their assessment. The most probable values for the characteristics of the emissions were estimated, such as the total released radioactivity, together with their corresponding uncertainty.<\/p>\n","innerContent":["\n

    Faced with these challenges, the work done by CEREA in collaboration with IRSN served to bolster inverse modeling<\/em> techniques based on a probabilistic method. It aims to quantify the characteristics of the discharge but also the uncertainties inherent in their assessment. The most probable values for the characteristics of the emissions were estimated, such as the total released radioactivity, together with their corresponding uncertainty.<\/p>\n"],"rendered":"\n

    Faced with these challenges, the work done by CEREA in collaboration with IRSN served to bolster inverse modeling<\/em> techniques based on a probabilistic method. It aims to quantify the characteristics of the discharge but also the uncertainties inherent in their assessment. The most probable values for the characteristics of the emissions were estimated, such as the total released radioactivity, together with their corresponding uncertainty.<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"The new method developed enables automatic adjustment of the temporal resolution of the description of the source term (its discretization) based on information from observations. It therefore facilitates the processing of the high temporal dynamic of long-term discharges.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    The new method developed enables automatic adjustment of the temporal resolution of the description of the source term (its discretization) based on information from observations. It therefore facilitates the processing of the high temporal dynamic of long-term discharges.<\/p>\n","innerContent":["\n

    The new method developed enables automatic adjustment of the temporal resolution of the description of the source term (its discretization) based on information from observations. It therefore facilitates the processing of the high temporal dynamic of long-term discharges.<\/p>\n"],"rendered":"\n

    The new method developed enables automatic adjustment of the temporal resolution of the description of the source term (its discretization) based on information from observations. It therefore facilitates the processing of the high temporal dynamic of long-term discharges.<\/p>\n"},{"blockName":"core\/image","attrs":{"id":7116,"sizeSlug":"large","linkDestination":"none","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/fig3_EN-1024x485.png","alt":"","caption":"Evolution of the release rate (Bq\/s) reconstructed by inverse modeling with the \u201creversible jump\u201d algorithm (RJ-MCMC, in blue) compared with other reconstructions proposed in the scientific literature (in green and pink). The shaded area corresponds to the estimated uncertainties associated with the release rate (Source)","lightbox":[],"title":"","href":"","rel":"","linkClass":"","width":"","height":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"align":"","className":"wp-block-image size-large","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    \"\"
    Evolution of the release rate (Bq\/s) reconstructed by inverse modeling with the \u201creversible jump\u201d algorithm (RJ-MCMC, in blue) compared with other reconstructions proposed in the scientific literature (in green and pink). The shaded area corresponds to the estimated uncertainties associated with the release rate (Source<\/a>)<\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Evolution of the release rate (Bq\/s) reconstructed by inverse modeling with the \u201creversible jump\u201d algorithm (RJ-MCMC, in blue) compared with other reconstructions proposed in the scientific literature (in green and pink). The shaded area corresponds to the estimated uncertainties associated with the release rate (Source<\/a>)<\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Evolution of the release rate (Bq\/s) reconstructed by inverse modeling with the \u201creversible jump\u201d algorithm (RJ-MCMC, in blue) compared with other reconstructions proposed in the scientific literature (in green and pink). The shaded area corresponds to the estimated uncertainties associated with the release rate (Source<\/a>)<\/figcaption><\/figure>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"The results obtained by this method show that the total quantity of radioactivity discharged into the atmosphere in the course of the Fukushima accident due to caesium-137would be between 10 to 20 Petabecquerels (PBq), with a most probable estimate of approximately 14 PBq, matching other studies [Saunier et al., 2013, Terada et al., 2020]. For comparison, the quantity of radioactivity of this radionuclide released during the Chernobyl accident was estimated to be 85 PBq.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    The results obtained by this method show that the total quantity of radioactivity discharged into the atmosphere in the course of the Fukushima accident due to caesium-137would be between 10 to 20 Petabecquerels (PBq), with a most probable estimate of approximately 14 PBq, matching other studies [Saunier et al., 2013<\/a>, Terada et al., 2020<\/a>]. For comparison, the quantity of radioactivity of this radionuclide released during the Chernobyl accident was estimated to be 85 PBq.<\/p>\n","innerContent":["\n

    The results obtained by this method show that the total quantity of radioactivity discharged into the atmosphere in the course of the Fukushima accident due to caesium-137would be between 10 to 20 Petabecquerels (PBq), with a most probable estimate of approximately 14 PBq, matching other studies [Saunier et al., 2013<\/a>, Terada et al., 2020<\/a>]. For comparison, the quantity of radioactivity of this radionuclide released during the Chernobyl accident was estimated to be 85 PBq.<\/p>\n"],"rendered":"\n

    The results obtained by this method show that the total quantity of radioactivity discharged into the atmosphere in the course of the Fukushima accident due to caesium-137would be between 10 to 20 Petabecquerels (PBq), with a most probable estimate of approximately 14 PBq, matching other studies [Saunier et al., 2013<\/a>, Terada et al., 2020<\/a>]. For comparison, the quantity of radioactivity of this radionuclide released during the Chernobyl accident was estimated to be 85 PBq.<\/p>\n"},{"blockName":"core\/columns","attrs":{"verticalAlignment":"","isStackedOnMobile":true,"templateLock":null,"lock":[],"metadata":[],"align":"","className":"wp-block-columns","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","layout":[],"anchor":""},"innerBlocks":[{"blockName":"core\/column","attrs":{"width":"50%","verticalAlignment":"","templateLock":null,"lock":[],"metadata":[],"className":"wp-block-column","style":"flex-basis:50%","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","layout":[],"anchor":""},"innerBlocks":[{"blockName":"core\/image","attrs":{"id":7118,"width":"326px","height":"auto","sizeSlug":"full","linkDestination":"none","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/fig4-pas-1.png","alt":"","caption":"Evolution of the average number of steps used each day to describe the temporal dynamics of rejection (red curve) and associated uncertainties (red area) (Author provided ).","lightbox":[],"title":"","href":"","rel":"","linkClass":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"align":"","className":"wp-block-image size-full is-resized","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    \"\"
    Evolution of the average number of steps used each day to describe the temporal dynamics of rejection (red curve) and associated uncertainties (red area) (Author provided ).<\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Evolution of the average number of steps used each day to describe the temporal dynamics of rejection (red curve) and associated uncertainties (red area) (Author provided ).<\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Evolution of the average number of steps used each day to describe the temporal dynamics of rejection (red curve) and associated uncertainties (red area) (Author provided ).<\/figcaption><\/figure>\n"}],"innerHTML":"\n
    <\/div>\n","innerContent":["\n
    ",null,"<\/div>\n"],"rendered":"\n
    \n
    \"\"
    Evolution of the average number of steps used each day to describe the temporal dynamics of rejection (red curve) and associated uncertainties (red area) (Author provided ).<\/figcaption><\/figure>\n<\/div>\n"},{"blockName":"core\/column","attrs":{"width":"50%","verticalAlignment":"","templateLock":null,"lock":[],"metadata":[],"className":"wp-block-column","style":"flex-basis:50%","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","layout":[],"anchor":""},"innerBlocks":[{"blockName":"core\/image","attrs":{"id":7120,"width":"335px","height":"auto","sizeSlug":"full","linkDestination":"none","blob":"","url":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/fig4-TRRA_EN.png","alt":"","caption":"Probability density associated with the amount of total radioactivity released in March 2011 (Author provided).","lightbox":[],"title":"","href":"","rel":"","linkClass":"","aspectRatio":"","scale":"","linkTarget":"","lock":[],"metadata":[],"align":"","className":"wp-block-image size-full is-resized","style":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n
    \"\"
    Probability density associated with the amount of total radioactivity released in March 2011 (Author provided).<\/figcaption><\/figure>\n","innerContent":["\n
    \"\"
    Probability density associated with the amount of total radioactivity released in March 2011 (Author provided).<\/figcaption><\/figure>\n"],"rendered":"\n
    \"\"
    Probability density associated with the amount of total radioactivity released in March 2011 (Author provided).<\/figcaption><\/figure>\n"}],"innerHTML":"\n
    <\/div>\n","innerContent":["\n
    ",null,"<\/div>\n"],"rendered":"\n
    \n
    \"\"
    Probability density associated with the amount of total radioactivity released in March 2011 (Author provided).<\/figcaption><\/figure>\n<\/div>\n"}],"innerHTML":"\n
    \n\n<\/div>\n","innerContent":["\n
    ",null,"\n\n",null,"<\/div>\n"],"rendered":"\n
    \n
    \n
    \"\"
    Evolution of the average number of steps used each day to describe the temporal dynamics of rejection (red curve) and associated uncertainties (red area) (Author provided ).<\/figcaption><\/figure>\n<\/div>\n\n\n\n
    \n
    \"\"
    Probability density associated with the amount of total radioactivity released in March 2011 (Author provided).<\/figcaption><\/figure>\n<\/div>\n<\/div>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"Finally, this approach, thanks to a reasonable computation time, can be used for other accidental situations. It was recently successfully applied to low-amplitude discharge events, such as forest fires in Ukraine and the detection of radionuclides in northern Europe in 2020.","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    Finally, this approach, thanks to a reasonable computation time, can be used for other accidental situations. It was recently successfully applied to low-amplitude discharge events, such as forest fires in Ukraine and the detection of radionuclides in northern Europe in 2020.<\/p>\n","innerContent":["\n

    Finally, this approach, thanks to a reasonable computation time, can be used for other accidental situations. It was recently successfully applied to low-amplitude discharge events, such as forest fires in Ukraine and the detection of radionuclides in northern Europe in 2020.<\/p>\n"],"rendered":"\n

    Finally, this approach, thanks to a reasonable computation time, can be used for other accidental situations. It was recently successfully applied to low-amplitude discharge events, such as forest fires in Ukraine and the detection of radionuclides in northern Europe in 2020.<\/p>\n"},{"blockName":"core\/paragraph","attrs":{"align":"","content":"","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    <\/p>\n","innerContent":["\n

    <\/p>\n"],"rendered":"\n

    <\/p>\n"},{"blockName":"core\/footnotes","attrs":{"lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","fontSize":"","fontFamily":"","borderColor":""},"innerBlocks":[],"innerHTML":"","innerContent":[],"rendered":""},{"blockName":"enpc\/accordion","attrs":{"title":"REFERENCE","lock":[],"metadata":[],"className":"wp-block-enpc-accordion","style":""},"innerBlocks":[{"blockName":"core\/paragraph","attrs":{"align":"","content":"thesis Joffrey Dumont Le Brazidec","dropCap":false,"placeholder":"","direction":"","lock":[],"metadata":[],"className":"","style":"","backgroundColor":"","textColor":"","gradient":"","fontSize":"","fontFamily":"","borderColor":"","anchor":""},"innerBlocks":[],"innerHTML":"\n

    thesis Joffrey Dumont Le Brazidec<\/a><\/p>\n","innerContent":["\n

    thesis Joffrey Dumont Le Brazidec<\/a><\/p>\n"],"rendered":"\n

    thesis Joffrey Dumont Le Brazidec<\/a><\/p>\n"}],"innerHTML":"\n

    <\/div>\n","innerContent":["\n
    ",null,"<\/div>\n"],"rendered":"\n
    \n

    thesis Joffrey Dumont Le Brazidec<\/a><\/p>\n<\/div>\n"}],"seo":{"title":"Identifying and quantifying radioactive substance emissions in the atmosphere"},"media":{"img":"\"\"","src":"https:\/\/ingenius.ecoledesponts.fr\/wp-content\/uploads\/2024\/11\/Fukushima-simulated-plume.png"},"url":"\/en\/articles\/identifying-and-quantifying-radioactive-substance-emissions-in-the-atmosphere\/","related":{"post":[],"author":[{"title":"Marc Bocquet","url":"\/en\/authors\/marc-bocquet\/","id":"6709","media":"\"\"","slug":"marc-bocquet"},{"title":"Joffrey Dumont Le Brazidec","url":"\/en\/authors\/joffrey-dumont-le-brazidec\/","id":"6720","media":"\"\"","slug":"joffrey-dumont-le-brazidec"},{"title":"Olivier Saunier","url":"\/en\/authors\/olivier-saunier\/","id":"7186","media":"\"\"","slug":"olivier-saunier"},{"title":"Yelva Roustan","url":"\/en\/authors\/yelva-roustan\/","id":"7197","media":"\"\"","slug":"yelva-roustan"}],"subject":[{"title":"Energy, Ecology & Climate","url":"\/en\/subjects\/energy-ecology-climate\/","id":"937","media":"\"\"","slug":"energy-ecology-climate"},{"title":"Digital Technology, Modeling & Artificial Intelligence","url":"\/en\/subjects\/digital-technology-modeling-artificial-intelligence\/","id":"690","media":"\"\"","slug":"digital-technology-modeling-artificial-intelligence"}],"category":[{"title":"Articles","url":"\/en\/articles\/category\/articles\/","id":"1716","media":"","slug":"articles","_related_post_type":""},{"title":"Article collection","url":"\/en\/articles\/category\/dossier\/","id":"1720","media":"","slug":"dossier","_related_post_type":"folder"}],"folder":[{"title":"Nuclear power : history, risks and challenges","url":"\/en\/folders\/nuclear-power-history-risks-and-challenges\/","id":"6913","media":"\"\"","slug":"nuclear-power-history-risks-and-challenges"}]},"translated":"https:\/\/ingenius.ecoledesponts.fr\/articles\/identifier-et-quantifier-les-emissions-de-substances-radioactives-dans-latmosphere\/","icon":"icon-article","duration":"4","custom_excerpt":"The nuclear industry generates radioactive discharges that require rigorous management to secure facilities and protect the environment. This article demonstrates the benefits of numerical modeling to predict and quantify discharges and their impacts, taking the accident that occurred at the Fukushima power plant as a case study.","duration_type":"","_links":{"self":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts\/7084","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/comments?post=7084"}],"version-history":[{"count":5,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts\/7084\/revisions"}],"predecessor-version":[{"id":8998,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/posts\/7084\/revisions\/8998"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/media\/7191"}],"wp:attachment":[{"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/media?parent=7084"}],"wp:term":[{"taxonomy":"article-types","embeddable":true,"href":"https:\/\/ingenius.ecoledesponts.fr\/en\/wp-json\/wp\/v2\/article-types?post=7084"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}