Study on the influence of geometric size of annular fuel element on thermal performance

Abstract

BackgroundCompared with conventional rod-type nuclear fuel, annular fuel has higher power density and better heat transfer efficiency, which can significantly improve the safety and economy of the reactor.PurposeThis study aims to investigate the effect of ring fuel element geometry on the thermal performance and to correct the initial parameters.MethodsThe initial parameters of the ring fuel element were set and the thermal conductivity calculation program of the ring fuel element was prepared. The effects of the ring fuel flow distribution ratio, inner and outer cladding thickness, inner and outer air gap thickness and core block thickness on the thermal performance of the ring fuel element were investigated by three evaluation criteria developed and geometric corrections are made.ResultsAppropriately increasing the flow distribution ratio, decreasing the inner casing thickness, increasing the outer casing thickness, decreasing the inner and outer air gap spacing and decreasing the core block thickness can improve the thermal performance of the components; setting the flow distribution ratio to 1, the inner casing thickness 0.06 cm is amended to 0.04 cm, the outer casing thickness 0.06 cm is amended to 0.07 cm, the inner and outer air gap spacing 0.035 cm. The thickness of core block is amended to 0.5 cm.ConclusionsThermal performance of annular fuel elements is significantly improved after appropriate geometry correction is made.

Keywords

• annular fuel element
• thermal-hydraulic performance
• geometric size modification
• thermal conducting model
• flow distribution ratio