Neutron detection apparatus

摘要

A neutron detector detects a neutron flux distribution of the inside of a reactor. The neutron detector includes a thimble guide tube that is inserted inside of the reactor, for inserting the neutron detector. A drive apparatus is connected to the thimble guide tube for inserting or extracting the neutron detector into or out of the thimble guide tube. A vacuum unit controls the vacuum state in the thimble guide tube. A supply unit supplies carbon dioxide gas. A gas purge unit is connected to the supply unit and conducts gas purge in the thimble guide tube. A gate valve is provided between the thimble guide tube and the drive apparatus, and performs an open/close operation. A control apparatus controls the gate valve, the drive apparatus, the vacuum unit, the supply unit, and the gas purge unit.

主权项

1. A neutron detection apparatus configured to detect a neutron flux distribution inside of a pressurized water reactor, the neutron detection apparatus comprising:
a neutron detector configured to detect the neutron flux distribution inside of the reactor; a thimble guide tube configured to be inserted into the reactor from the outside of the reactor, for inserting the neutron detector inside of the reactor; a drive apparatus which is connected to the thimble guide tube and which inserts the neutron detector into the thimble guide tube or extracts the neutron detector out of the thimble guide tube; a vacuum unit which controls a vacuum state in the thimble guide tube; a supply unit which supplies carbon dioxide gas; a gas purge unit which is connected to the supply unit and conducts gas purge in the thimble guide tube via the flow of carbon dioxide gas into the thimble guide tube; a gate valve which is provided between the thimble guide tube and the drive apparatus and opens or closes to allow or prevent communication between the thimble guide tube and the drive apparatus; and a control apparatus which controls the gate valve, the drive apparatus, the vacuum unit, the supply unit, and the gas purge unit, so that when the gate valve is closed, first flow of carbon dioxide gas flows inside the thimble guide tube, and when the gate valve is opened, a second flow of carbon dioxide gas, smaller than the first flow, flows inside the thimble guide tube.