B and Gd-containing overall composite combustible toxic fuel and preparation method

Abstract

The invention belongs to a combustible toxic fuel, in particular to a B and Gd-containing overall composite combustible toxic fuel and a preparation method. The fuel aims to control excess reactivity and meets the requirements of long-period reactivity control and moderator negative temperature coefficient control on the composite combustible toxic fuel. The composite combustible toxic fuel consists of a ZrB2 coating and a UO2-Gd2O3, wherein the UO2-Gd2O3 comprises 2 to 12 mass percent of Gd2O3; and the linear density of concentrated <10>B is 0.1 to 1.0 mg / cm. By using the overall composite combustible toxic fuel, the requirements of the long-period reactivity control and the moderator negative temperature coefficient control on the composite combustible toxic fuel can be met; moreover, the cost of the composite combustible toxic fuel is lower than that of an Er-containing combustible toxic fuel. Simultaneously the service life of a reactor core is prolonged, the refueling period is prolonged and the nuclear power operation cost is reduced, so that the refueling period of a light-water reactor nuclear power station fuel can reach 24 to 48 months.

Description

technical field [0001] The invention belongs to a burnable poison fuel and a preparation method thereof, in particular to an integral composite burnable poison fuel containing B and Gd and a preparation method thereof. Background technique [0002] For high burnup fuel assemblies, due to their long service life and high abundance of fissionable elements, when new fuel assemblies are put into the reactor, combustible poisons should be used reasonably to flatten the neutron flux distribution in the core to achieve long-period reactions Positive control and negative temperature coefficient control of the moderator are required to increase the core life. There are two main types of combustible poisons used in PWR cores at home and abroad, one is discrete, and the other is combined with fuel, which can be referred to as integral for short. Discrete burnable poisons mainly include borosilicate glass tubes contained in stainless steel casings and ring-shaped alumina-boron carbide ...

AI Technical Summary

Problems solved by technology

But Er is expensive, UO 2 -Er 2 o 3 with UO 2 -Gd 2 o 3 The composite sintering process of double-layer fuel pellets is difficult and has poor quality stability