Research on NCRs of Domestic-Made SA-508 Heavy Forgings for the Third Generation Passive Nuclear Power Plant
-
Abstract
SA-508 Gr.3 Cl.1 and Cl.2 forgings for RPV and SG of the third generation passive nuclear power plant possess characters of top-level design requirements and high manufacturing difficulties. During the domestic production progress, a certain number of Non Conformance Report (NCR) on mechanical properties were submitted. Design requirements and deviations from ASME code about SA-508 Gr.3 Cl.1 and Cl.2 forgings were studied. The quantitative analysis on the mechanical properties of the forgings was carried out. Results show that low fracture toughness accounts for the major parts of NCR for RPV forgings, while both the low fracture toughness and lower tensile strength are the main reasons of NCR for SG forgings. A research on chemical and heat treatment specialties of SA-508 Gr.3 Cl.1 and Cl.2 forgings used for RPV and SG of was also carried out, in which the contributing factors and countermeasures on the quality instability of domestic-made heavy forgings were studied. In order to overcome the conflict between the manufacturing actuality and design requirements, it makes senses to optimize the process or develop a new process to improve the heavy frogings′ properties.
-
-
DownLoad: