Atmospheric dispersion of radionuclides from the Fukushima-Daichii nuclear power plant

CEREA, joint laboratory École des Ponts ParisTech and EdF R&D

Victor Winiarek, Marc Bocquet

Yelva Roustan, Camille Birman, Pierre Tran

Map of ground deposition of caesium-137 for the Fukushima-Daichii accident (updated 20 June 2013).

The simulation was performed with a specific version of the numerical atmospheric chemistry and transport model Polyphemus/Polair3D. The parametrisations used for the transport and physical removal of the radionuclides are described in [6,7,8,9].

The source term has been estimated by the assimilation of activity concentrations in the air as well as activity deposited on the ground [1,2].

The magnitude of the deposition field is uncertain and the simulated values of deposited radionuclides could be significantly different from the actual deposition. In particular, the source term remains uncertain, athough its uncertainty has been narrowed down thanks to data assimilation.

Other results obtained by collaborators about the Fukushima radionuclides dispersion accident are references below [3,4,5].

Map of ground deposition of caesium-137 for the Chernobyl accident

The simulation was performed with a specific version of the numerical atmospheric chemistry and transport model Polyphemus/Polair3D. The parametrisation used for the transport and physical removal of the radionuclides are described in [6,7,8,9].

The source term has been estimated by the assimilation of activity concentrations in the air [8].

The magnitude of the deposition field is uncertain and the simulated value of deposited radionuclides could be different from the actual from the actual deposition. However the source term is much better known than for Fukushima-Daichii. A comparison with deposition measurements will be conducted to evaluate the simulation.

Movie of the Fukushima-Daichii activity in the air (caesium-137, ground level, updated 20 June 2013)

The simulation was performed with a specific version of the numerical atmospheric chemistry and transport model Polyphemus/Polair3D. The parametrisations used for the transport and physical removal of the radionuclides are described in [6,7,8,9].

The source term has been estimated by the assimilation of activity concentrations in the air as well as activity deposited on the ground [1,2].

The magnitude of activity concentration field is uncertain and could be significantly different from the actual one. In particular, the source term remains uncertain. Therefore, these results should be seen as preliminary and they are likely to be revised as new information become available to better constrain the source term and when radionuclides data can be used to evaluate the model simulation results.

Dispersion of radionuclides in the ocean: see the coastal simulations of the Sirocco team here.

References (updated 9 January 2014):

1. Estimation of Errors in the Inverse Modeling of Accidental Release of Atmospheric Pollutant: Application to the Reconstruction of the Cesium-137 and Iodine-131 Source Terms from the Fukushima Daiichi Power Plant. V. Winiarek, M. Bocquet, O. Saunier and A. Mathieu. J. Geophys. Res. Atmospheres, 117, D05122, 2012.
2. Estimation of the caesium-137 source term from the Fukushima Daiichi nuclear power plant using a consistent joint assimilation of air concentration and deposition observations. V. Winiarek, M. Bocquet, N. Duhanyan, Y. Roustan, O. Saunier and A. Mathieu. Submitted, Atmo. Env., 82, 268-279, 2014.
3. An inverse modeling method to assess the source term of the Fukushima nuclear power plant accident using gamma dose rate observations. O. Saunier, A. Mathieu, D. Didier, M. Tombette, D. Quélo, V. Winiarek, and M. Bocquet. Atmos. Chem. Phys., 13, 11403--11421, 2013.
4. Assessment of the amount of Cesium-137 released into the Pacific Ocean after the Fukushima accident and analysis of its dispersion in Japanese coastal waters. C. Estournel, E. Bosc, M. Bocquet, C. Ulses, P. Marsaleix, V. Winiarek, I. Osvath, C. Nguyen, T. Duhaut, F. Lyard, H. Michaud, and F. Auclair, Journal of Geophysical Research Oceans, 117, C11014, 2012.
5. État de la modélisation pour simuler l'accident nucléaire de la centrale Fukushima Daiichi. Mathieu, A., I. Korsakissok, D. Quélo, O. Saunier, J. Groëll, D. Didier, D. Corbin, J. Denis, M. Tombette, V. Winiarek, M. Bocquet, E. Quentric, J.-P. Benoit. Pollut. Atmos., 217, in press, 2013.
6. Towards the operational estimation of a radiological plume using data assimilation after a radiological accidental atmospheric release. V. Winiarek, J. Vira, M. Bocquet, M. Sofiev and O. Saunier. Atmos. Env., 45, 2944-2955, 2011.
7. Targeting of observations for accidental atmospheric release monitoring (Abstract, Overview). R. Abida and M. Bocquet. Atmos. Env., 43, 6312-6327, 2009.
8. Inverse modelling-based reconstruction of the Chernobyl source term available for long-range transport. X. Davoine and M. Bocquet, Atmo. Chem. Phys., 7, 1549-1564, 2007.
9. Validation of the Polyphemus platform on the ETEX, Chernobyl and Algeciras cases D. Quélo, M. Krysta, M. Bocquet, O. Isnard, Y. Minier and B. Sportisse, Atmos. Env., 41, 5300-5315, 2007.