Abstract:
PURPOSE: A fixed in-core instrument of a nuclear reactor and a neutron detecting method using the same are provided to secure a plurality of output values in one measurement point by using a main detecting unit to detect a neutron and a sub detection unit to detect the measurement point according to the movement of the in-core instrument. CONSTITUTION: An in-core instrument(10) includes a main detecting unit(11) to detect a neutron of a nuclear fuel assembly and a sub detecting unit(12). The nuclear fuel assembly is divided into a nuclear fuel part without the in-core instrument and a nuclear fuel part(2b) with the in-core instrument. The main detecting unit corresponds to the measurement point to detect the output of the neutron of the set measurement point. The sub detecting unit is located in the measurement location. The sub detecting unit is composed of a top sub detecting part(12a) and a bottom sub detecting part(12b).
Abstract:
PURPOSE: A fixed in-core instrument of a nuclear reactor including a shielding unit and a method for detecting neutrons using the same are provided to continuously correct an output value of a neutron from a plurality of first detecting units using an output value measured by a second detecting unit with a relatively low radiation exposure frequency. CONSTITUTION: An in-core instrument(10) is sealed in a nuclear reactor of a high temperature and high pressure. The in-core instrument includes a first detecting unit(11) and a second detecting unit(12) to detect neutrons of a nuclear fuel assembly. The first detecting unit detects the output of the neutrons in a measurement point of the nuclear fuel assembly. The second detecting unit includes a top second detecting unit(12a) and a bottom second detecting unit(12b) which are arranged on both ends of the first detecting unit. A guide tube(4) guides an in-core instrument inserted through a sealing table to the inside of the nuclear reactor. A shielding unit(4a) is made of various materials to effectively shield radiation.