Optical fiber scope for inspecting fuel assembly

Since a fiber scope has only one objective section, it has to observe a plurality of places successively. Then, if the time for the observation is long, the objective section is deteriorated by radiation rays, which causes a problem of interrupting the observation and increasing operator's radiation dose. In view of the above, one or two light guides are combined with an image guide to form one objective section, and a plurality of them are formed in parallel and gathered as a comb-like shape. A prism is put into a window of the objective section and resins are filled or a glass cover is attached, to make the objective section smooth and flat. Compared with the case of using only one objective section, it is no more necessary for successive observation, and objection can be conducted at one time. For example, if a fiber scope having nine objective sections is used for observing 8 x 8 arrangement fuel assembly, the observation time is shortened to 1/9. Since the prism, the glass cover, and the resins are used for making the window flat, cruds deposited between the optical fiber and a reflection mirror are easily removed, to obtain clear images. (N.H.)