Nuclear Techniques ›› 2017, Vol. 40 ›› Issue (5): 50605-050605.doi: 10.11889/j.0253-3219.2017.hjs.40.050605

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

FAD of different welded structures for joining safe end to pipe-nozzle of nuclear pressure vessel

PAN Jianbin, WANG Guozhen, XUAN Fuzhen, TU Shandong   

  1. Key Laboratory of Pressure Systems and Safety, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
  • Received:2016-12-29 Revised:2017-03-08 Online:2017-05-10 Published:2017-05-03
  • About author:10.11889/j.0253-3219.2017.hjs.40.050605
  • Supported by:

    Supported by National Natural Science Foundation of China (No.51575184,No.51375165)

Abstract:

Background: Dissimilar metal welded joints (DMWJ) were indicated to be vulnerable components in the primary system, and an accurate structural integrity assessment for such DMWJ is needed. Three-material DMWJ structures without buttering layer are also applied in recent years. Purpose & Methods: In order to understand the effects of crack locations and crack sizes on failure assessment diagrams (FAD), FADs of two types of dissimilar metal welded structures (four-material structure with buttering layer and three-material structure without buttering layer) for joining safe end to pipe-nozzle of nuclear pressure vessel were constructed by finite element numerical analysis. Results: Limit loads of the two welded structures are basically the same, and the crack locations almost have no effects on the limit loads. With moving crack location from pipe nozzle to 316L safe end pipe and increasing crack depth, the failure assessment curves (FACs) shift downward and the safety margin of the cracked structure decreases. Conclusions:Because the FADs and limit loads of the cracks with the same location and size in the two welded structures are basically the same, their properties against fracture failure and structural strength are almost the same. It is feasible to connect pipe-nozzle with safe end using simplified manufacture process without buttering layer for the consideration of cost saving.

Key words: FAD, DMWJ, Nuclear pressure vessel, Safe end, Crack

CLC Number: 

  • TL48