18-09-2014 дата публикации
Номер: US20140270039A1
The present invention relates to devices and methods for measuring neutron fluence at a pre-selected location which is positioned in a nuclear power plant. The devices and methods include passing neutrons through a fiber optic cable. The fiber optic cable has disposed therein a neutron sensitive material which is capable of absorbing the neutrons to produce a gas. The gas results in a build-up of pressure in the fiber optic cable which causes a change in the optical stress birefringence pattern. This change is measured and used to determine the amount of gas in the fiber optic cable, the number of neutrons absorbed by the neutron sensitive material and subsequently, the neutron fluence at the pre-selected location. 1. A device to measure neutron fluence in a pre-selected location in a nuclear power plant , the pre-selected location comprising a presence of neutrons , the device comprising:a fiber optic cable having a length and an outer surface which forms an cavity, the cavity extending through the length of the fiber optic cable;a neutron sensitive material substantially uniformly contained in the cavity, the neutron sensitive material effective to at least partially absorb the neutrons to produce a gas;an optical measurement tool for measuring a change in an optical stress birefringence pattern of the fiber optic cable, the change produced from a build-up of pressure as a result of the gas produced; anda means for determining an amount of the gas in the fiber optic cable and an amount of neutrons absorbed by the neutron sensitive material to determine total neutron exposure in the pre-selected location.2. The device of claim 1 , wherein the cavity has one or more cores formed therein.3. The device of claim 1 , wherein the one or more cores each substantially uniformly contains the neutron sensitive material.4. The device of claim 1 , wherein the gas is selected from the group consisting of hydrogen claim 1 , helium and mixtures thereof.5. The device of claim 1 , ...
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