# Measurement of Individual Dose from External Exposure among All Citizens of Date City 5 to 51 Months after the Fukushima NPP Accident: Prediction of Lifetime Additional Dose and Evaluating the Effect of Decontamination on Individual Dose

## TL;DR

This study estimates the lifetime external radiation dose for residents of Date City post-Fukushima, finding it unlikely to exceed 18 mSv and showing limited impact of decontamination efforts on dose reduction.

## Contribution

It introduces a method combining individual badge data with ambient dose reduction functions to predict residents' lifetime doses in contaminated areas.

## Key findings

- Average lifetime dose estimated at not exceeding 18 mSv.
- Decontamination effects on dose reduction were not clearly observed.
- Method enables reliable prediction of long-term doses for residents.

## Abstract

In the first paper of this series, we showed that the ratio c of individual dose to ambient dose did not change with time in Date City, Fukushima Prefecture, after the Fukushima Daiichi Nuclear Power Plant accident. The purpose of the present paper, the second in a series, is to estimate the lifetime doses of the Date City residents, based on continuous glass badge monitoring data, extrapolated by means of the ambient-dose-rate reduction function obtained from the airborne monitoring data. As a result, we found that the mean additional lifetime dose of residents living in Date City is not expected to exceed 18 mSv. In addition, effects of decontamination on the reduction of individual doses were not evident. This method of combining individual doses and the ambient doses, as developed in this study, has made it possible to predict with reasonable certainty the lifetime doses of residents who continue to live in this radiologically contaminated area.