The Comparison of High-Temperature Creep Deformation and Failure of RBMK and CANDU Pressure Tubes

Abstract

The experimental investigation of RBMK pressure tubes ballooning during overheating was carried out in RDIPE and EREC (Russia). The test results were treated to obtain pressure tubes creep rate data. The correlations for high-temperature creep rate of Zr+2.5%Nb alloy have been worked out by means of treatment a lot of proper test data. Well-known creep-equations for pressure tubes of CANDU reactor were used and modified. The validation of modified creep-equations was done using the results of RBMK pressure tube ballooning tests. Creep-rate equations were presented as a computer code where the activation energy of creep is determined as a function of current tube temperature. The test data obtained were used to develop the pressure tube failure criteria at accident heating. The comparison of temperature criterion correlations for RBMK and CANDU pressure tubes showed the good agreement in wide range of tube temperature and channel pressure.