Study of Overlay Technology for the Repair Control Rod Drive Mechanism Canopy Seal Weld
|School||Shanghai Jiaotong University|
|Course||Nuclear energy and nuclear science and technology|
|Keywords||The control rod drive mechanism (CRDM) Seal weld Surfacing Technology Residual stress Crack propagation|
Control rod drive mechanism is a nuclear reactor critical sensitive parts , upper the Ω a sealed weld (UCSW) defects will lead to leakage of radioactive material have been many incidents of Ω seal weld leakage accident at home and abroad , bring serious harm to the safety of the reactor . In this paper, the upper part of the Ling Ao Nuclear Power Station Unit 1 in CRDM H14 sealed weld area for non-destructive testing and metallurgical anatomical analysis to infer crack more likely to corrosion caused by the stress of work hardening and surfacing repair programs. The probability of occurrence of SCC according to the alloy , alloy welding technology requirements and welding process caused the dilution phenomenon of two for Alloy52 alloy demonstrated the ability to resist the SCC . In this paper, the finite element software ANSYS launched an in-depth evaluation of the Ω seal weld structural strength . Calculated by thermal analysis and stress analysis of the structure of residual stress distribution in the structure after the implementation of the surfacing . The residual stress analysis of the results of the stress intensity factor of the projected structure , and then carry out the crack growth analysis of the structure . The results show that , assume that the final size of the crack growth than the ASME allowable defect size smaller , surfacing to ensure the seal weld structure to maintain the safe operation of the state during the life of the power station . Also, comparative analysis of a variety of repair plans and gives the feasibility of the selected plan , described in detail the contents of the maintenance plan .