First demonstration of a single-end readout position-sensitive optical fiber radiation sensor inside the Fukushima Daiichi Nuclear Power Station based on wavelength-resolving analysis

波長分解分析に基づく片側読み出し型光ファイバ放射線位置検出器の福島第一原子力発電所における初実証

寺阪 祐太   ; 佐藤 優樹  ; 瓜谷 章*

Terasaka, Yuta; Sato, Yuki; Uritani, Akira*

We have developed a new position-sensitive optical fiber radiation sensor that achieves single-end readout and high dose rate application. The sensor determines the incident position of radiation on the optical fiber by using the wavelength dependency of light attenuation within the fiber. Through the analysis of the output wavelength spectrum from the fiber end, the incident position of radiation on the optical fiber can be inversely estimated using the spectrum unfolding procedure. Using this optical fiber sensor, we conducted a measurement of radiation distribution inside the Fukushima Daiichi Nuclear Power Station (FDNPS). The actual trend of incident position of radiation was successfully reproduced in a high dose rate area, with a maximum dose rate exceeding 100 mSv/h. This validates the effectiveness of our new position-sensitive optical fiber radiation sensor.