Spatial and temporal prediction of radiation dose rates near Fukushima Daiichi Nuclear Power Plant

Journal Article · 22 June 2022 · Journal of Environmental Radioactivity

DOI: https://doi.org/10.1016/j.jenvrad.2022.106946 · OSTI ID:1994348

Sun, Dajie  ^[1]; Wainwright, Haruko ^[2]; Suresh, Ishita ^[3]; Seki, Akiyuki ^[4]; Takemiya, Hiroshi ^[4]; Saito, Kimiaki ^[4]

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1. Univ. of California, Berkeley, CA (United States)
2. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
3. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
4. Japan Atomic Energy Agency (JAEA), Oarai (Japan)

In this paper, we have developed a methodology to estimate the spatiotemporal distribution of radiation air dose rates around the Fukushima Daiichi Nuclear Power Plant (FDNPP). In our exploratory data analysis, we found that (1) the temporal evolution of dose rates is composed of a log-linear decay trend and fluctuations of air dose rates that are spatially correlated among adjacent monitoring posts; and (2) the slope of the log-linear environmental decay trend can be represented as a function of the apparent initial dose rates, coordinate position, land-use type, and soil type. From these observations, we first estimated the log-linear decay trend at each location based on these predictors, using the random forest method. We then developed a modified Kalman filter coupled with a Gaussian process model to estimate the dose-rate time series at a given location and time. We applied this method to the Fukushima evacuation zone (as of March 2017), which included 17 monitoring post locations (with monitoring datasets collected between 2014 and 2018) and generated a time series of dose-rate maps. Our results show that this approach allows us to produce accurate spatial and temporal predictions of radiation dose-rate maps using limited spatiotemporal measurements.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: Japan Atomic Energy Agency; USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1994348
• Journal Information: Journal of Environmental Radioactivity, Journal Name: Journal of Environmental Radioactivity Vol. 251-252; ISSN 0265-931X
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English