Nuclear Techniques ›› 2019, Vol. 42 ›› Issue (10): 100601-100601.doi: 10.11889/j.0253-3219.2019.hjs.42.100601

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Analysis and evaluation of stress relaxation for the high temperature bolt connecting structure in scram system of the TMSR-LF1

Zuokang LIN1,2,Wen WANG1,2,Huiqing FAN1,2,Maoyuan CAI1,2,Lifang ZHAI1,2,Xiaochun ZHANG1,2()   

  1. 1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
    2. Institute of Advanced Nuclear Energy Innovation, Chinese Academy of Sciences, Shanghai 201800, China
  • Received:2019-07-04 Revised:2019-07-24 Online:2019-10-13 Published:2019-10-21
  • Contact: Xiaochun ZHANG
  • About author:LIN Zuokang, male, born in 1984, graduated from University of Chinese Academy of Sciences with a doctoral degree in 2013, focusing on nuclear technology and application
  • Supported by:
    the Strategic Priority Research Program of Chinese Academy of Sciences(XDA02010000)

Abstract: Background

The temperature of the bolt connecting structure is around 650 ℃ in the scram system of the thorium molten salt reactor-liquid fuel 1 (TMSR-LF1) and the connecting components include three kinds of material, which have different coefficients of thermal expansion. Thermal expansion during the heating process, from room temperature to 650 ℃, and creep in the long lifetime of reactor will affect the bolt pretension, which may touch the safety of the scram system.


This study aims to analyse the stress relaxation of the bolting structure, and assess structural safety for the scram system of TMSR-LF1.


The ANSYS program was employed for the mechanical analysis of the bolt connecting model. The stress analysis and creep stress-relaxation analysis of the structure under the combined action of bolting preload and thermal expansion were performed.


The high temperature creep of bolted structural materials and the variation of stress relaxation caused by the creep and its influence on the pre-tightening force of bolted connection structures are obtained for the whole lifetime of the reactor. And the evaluation of the bolt is completed under.


According to American society of mechanical engineers (ASME) standard in coordinate with ASME-III-5-HBB rules for bolt mechanical analysis and safety evaluation, the connecting bolt structure designed for TMSR-LF1 is demonstrated safe and reliable in the whole lifetime.

Key words: High temperature creep, Stress relaxation, Bolt pretension, Mechanical analysis

CLC Number: 

  • TL99