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http://dx.doi.org/10.3795/KSME-A.2012.36.10.1235

Evaluation for Weld Residual Stress and Operating Stress around Weld Region of the CRDM Nozzle in Reactor Vessel Upper Head  

Lee, Kyoung-Soo (Central Research Institute, Korea Hydro and Nuclear Power Co. Ltd.)
Lee, Sung-Ho (Central Research Institute, Korea Hydro and Nuclear Power Co. Ltd.)
Bae, Hong-Yeol (Dept. of Mechanical Engineering, Korea Univ.)
Publication Information
Transactions of the Korean Society of Mechanical Engineers A / v.36, no.10, 2012 , pp. 1235-1239 More about this Journal
Abstract
Primary water stress corrosion cracking (PWSCC) has been observed around the weld region of control rod drive mechanism (CRDM) nozzles in nuclear power plants overseas. The weld has a J-shaped groove and it connects the CRDM nozzle with the reactor vessel upper head (RVUH). It is a dissimilar metal weld (DMW), because the CRDM is made of alloy 600 and the RVUH is made of carbon steel. In this study, finite element analysis (FEA) was performed to estimate the stress condition around the weld region. Generally, it is known that a high tensile region is more susceptible to PWSCC. FEA was performed as for the condition of welding, hydrostatic test and normal operation successively to observe how the residual stress changes due to plant condition. The FEA results show that a high tensile stress region is formed around the weld starting point on the inner surface and around the weld stop point on the outer surface.
Keywords
Weld Residual Stress; Finite Element Analysis; Reactor Upper Vessel Head; Control Rod Drive Mechanism Nozzle;
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Times Cited By KSCI : 4  (Citation Analysis)
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