Inverse Modeling for Aquatic Source and Transport Parameters Identification and its Application to Fukushima Nuclear Accident
- 215 Downloads
Inverse modeling technique based on nonlinear least square regression method (LSRM) is developed for the identification of aquatic source and transport parameters. Instantaneous line source release model in two-dimensional domain and continuous point source release model in three-dimensional domain are used for the purpose. Case studies have been carried out for both types of releases to illustrate their application. Error analysis has been carried out to identify the maximum error that can be tolerated in the input concentration data used in the inverse model and to specify the minimum number of sampling points to generate such input data. The LSRM is compared with the well-established correlation coefficient optimization method for instantaneous line source release model, and good comparison is observed between them. The LSRM is used to quantitatively estimate the releases of different radionuclides into the Pacific Ocean which has resulted due to the discharge of highly radioactive liquid effluent from the affected Daiichi Nuclear Power Station at Fukushima in Japan. The measured concentrations of these radionuclides in seawater samples collected from two sampling points near Fukushima are used for the estimation. The average release works out to be 1.09 × 1016 for 131I, 3.4 × 1015 Bq for 134Cs, and 3.57 × 1015 Bq for 137Cs. Very good agreement is observed between the releases estimated in this study and those estimated by other different agencies.
KeywordsFukushima DNPS Surface water LSRM Radionuclide
- 1.Sidauruk, P. (1996). Parameter determination for multi-layered aquifer and groundwater contaminant transport. Ph.D. Diss., University of Delaware.Google Scholar
- 7.David, C. L. (1996). Linear algebra and its applications (2nd ed.). Boston: Addison Wesley.Google Scholar
- 8.Ortega, J., & Rheinboldt, W. (1970). Iterative solution of nonlinear equations in several variables. New York: Academic.Google Scholar
- 9.Bear, J. (1979). Hydraulics of groundwater. New York: McGraw-Hill.Google Scholar
- 10.Socolofsky, S. A., & Jirka, G. H. (2005). CVEN 489–501: special topics in mixing and transport processes in the environment. USA: Coastal and Ocean Engineering Division, Texas A&M University.Google Scholar
- 11.IRSN (2011). Impact on the marine environment of radioactive releases following the nuclear accident at Fukushima Daiichi. Information Note dated 13 May 2011. Institute for Radiological Protection and Nuclear Safety, France.Google Scholar
- 13.TEPCO (2011). http://www.tepco.co.jp/en/press/corp-com/release. Tokyo Electrical Power Company, Japan.
- 14.TEPCO (2012). http://www.tepco.co.jp/en/press/corp-com/release. Tokyo Electrical Power Company, Japan.
- 20.Nair, R. N., Faby Sunny, Manish Chopra, Sharma, L. K., Puranik, V. D., and Ghosh, A. K. (2013). Estimation of radionuclide releases into Pacific Ocean due to Fukushima nuclear accident. Environmental Earth Sciences. doi: 10.1007/s12665-013-2501-I.