Hitachi-ge Nuclear Energy, Ltd.

Ryusuke Kimura

Hiroshi Kitaguchi

Takahiro Tadokoro

Katsunori Ueno

Yutaka Iwata

A gamma scanning apparatus includes a moving and fixing mechanism which moves/fixes a housing to a definite position, and a rotating and moving mechanism which moves a fuel assembly vertically in addition to rotating the assembly. A gamma-ray counting circuit measures an output of a gamma-ray detector, and a data collecting/analyzing and controlling apparatus analyzes data output from the gamma-ray counting circuit, in association with data relating to the rotation and movement of the fuel assembly by the rotating and moving mechanism. The rotating and moving mechanism, after fixing the vertical position of the fuel assembly with the housing also fixed, rotates the fuel assembly through 360&#xb0; with its height kept constant, and during the 360&#xb0; rotation of the fuel assembly, the gamma-ray counting circuit measures either a time average of count values of the detector during the rotation or an integral value within a fixed time.

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Hitachi, Japan

Ryusuke Kimura