Temperature Distribution in Connection Zones During Heat-Treatment of Weld Joints

Cracking of the weld joints in Du300 austenitic pipelines, which are part of multiple forced circulation loops, remains an urgent problem in spite of the compensatory measures adopted. The multiple forced circulation loop in RBMK-1000 is a complicated system of pipelines with different diameters, equipment and fixtures made of different materials. Its separate elements have different geometry and structural features in different power-generating units. High-temperature heat treatment makes it possible to adopt compensatory measures under cramped conditions in complex geometry without degrading the reliable results of ultrasonic monitoring. For safety in NPPs, it is necessary to meet the requirements specified in the normative-technical documentation. Calculations of the heat exchange in the structure elements were performed to meet them. The computational results are presented here.