| 摘要 |
PURPOSE: To obtain the monitor of a neutron bundle existing in the neighborhood of the core of a reactor during operation wherein various disadvantages seen in a prior art can be overcome while inherent neutron measuring characteristics are fully held. CONSTITUTION: A few groups of neutron detectors connected to chains, an electronic circuit and the state of a connection part are in the vertical axes 8-22 of concrete near a vessel 4, and a light source and an intermediate and output three chain type are formed of the detectors. At least one of them is a nuclear fission chamber 50, and a high sensitivity detector 26 and the nuclear fission chamber 50 are provided with each of the all axes. Each detector is positioned in tubes 24, 28 extending over the height of the axis, and its insertion and removal are constituted to be performed regardless of other detectors.
|
