Method for replacing primary neutron source with irradiated fuel assemblies

Abstract

The invention discloses a method for replacing a primary neutron source with irradiated fuel assemblies. A primary neutron source assembly is not loaded or used by a reactor core; one or more irradiated fuel assemblies obtained from other running reactors are loaded in a first cycle; the neutron counting rate of a detector meets the requirements by using neutrons released by the irradiated fuel assemblies; and meanwhile, fissile nuclides preserved by the irradiated fuel assemblies meet the physical design requirements of the first cycle. The method has the beneficial effects that the fuel assemblies generate the nuclides capable of reacting with (alpha, n) to generate the neutrons through self-fission reaction after two cycles, meanwhile, a lot of fissile nuclides still exist in the fuel, and the primary neutron source is replaced with the irradiated fuel assemblies, so that the problems of Cf-252 source production, equipment manufacturing or radiation protection caused by a primary neutron source assembly are solved under the condition of meeting the reactor core loading and critical safety supervision starting requirements.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor design, in particular to a method for using irradiated fuel elements to replace primary neutron sources. Background technique [0002] During the charging and start-up of the reactor, it is necessary to monitor the fission reaction rate and its changes in the core, so as to prevent the reactor from reaching an uncontrollable instantaneous critical state. For nuclear power plants in service in China, in the first cycle, the monitoring uses external source range detectors, which are far away from the core, and a neutron source (usually a Cf-252 source) is introduced into the core, which can improve the detection efficiency of the detectors. neutron fluence rate and count rate. At present, a typical pressurized water reactor nuclear power plant core will introduce two primary neutron source components into the core symmetrically. [0003] The use of a primary neutron source has the followin...

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Problems solved by technology

[0003] The use of primary neutron source has the following disadvantages: 1) Cf-252 source is difficult to produce and the production cost is high; 2) Special primary neutron source components need to be designed and manufactured, adding additional equipment

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