Basic R&D on laser remote analysis for in-situ monitoring of nuclear debris in decommissioning of "Fukushima Daiichi Nuclear Power Station"

Wakaida, Ikuo  ; Oba, Hironori  ; Akaoka, Katsuaki ; Miyabe, Masabumi   ; Oba, Masaki ; Matsumoto, Ayumu*; Sakka, Tetsuo*; Taira, Takunori*; Ikeda, Yuji*

For the decommissioning of "Fukushima Daiichi Nuclear Power Station (F1NPS)" which has damaged or melt downed nuclear core, matting with basic R&D and actual application technologies for decommissioning work will be strongly required. CLADS/JAEA is one of the key institute for strategic promotion of Decommissioning Science on F1NPS in Japan. As for the development of rapid, easy, onsite and in-situ remote diagnostic/analysis of debris under the severe environments such as extremely high radioactive condition, the concept of probing by light and diagnostic by light with radiation resistant optical fiber will be one of the simple, powerful and applicable choices as the innovative development based on LIBS technique. Radiation resistant Optical Fiber based LIBS probe (Fiber LIBS) is constructed, and its activity is demonstrated under water condition and high radiation condition of about 10 kGy/h. For higher sensitivity, Long pulse laser with the pulse duration about 100 ns, and Microwave assisted LIBS are performed. The challenge for longer light delivery (100 m) and flexible use, self Q-switched Microchip laser will be under developing for the LIBS probe and its activity under high radiation condition is now demonstrated.