Design on cladding of central measuring shroud against thermal shock in FR based on elastoplastic model

Abstract

The thermal shock caused by scram conditions greatly affects the service life of central measuring shroud. Cladding, as a protective layer, can be adopted to protect the central measuring shroud. In this study, a cladding design procedure based on elastoplastic model was proposed and verified by experiment. Then, the cladding thickness and gap distance were designed. And the temperature and strain distribution were analyzed and discussed. It was found that under thermal shock condition, the cladding thickness and gap distance should be at least 2 mm and 2.66 mm to guarantee safety. Compared to elastic model, the design results of elastoplastic model are reduced by 50 % for cladding thickness and 33.5 % for gap distance. The increase of cladding thickness is beneficial for central measuring shroud, but harmful for cladding. The alternating tensile and compressive strain caused by temperature changes is the main reason for total strain fluctuation.