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3-D thermal stress analysis of hot spots in reactor piping using BEM

Technical Report:

Abstract

A three-dimensional steady state thermoelastic analysis has been conducted on the hot leg of a pressurized water reactor(PWR) containing localized hot spots resulting from fission product aerosol deposition occurring during a hypothetical severe accident. The boundary element method (BEM) of numerical solution was successfully employed to investigate the structural response of the hot leg. Convergence of solution can be realized provided sufficiently large number of elements are employed and correct modelling of the temperature transition region (TTR) adjacent to the hot spot on the inner surface is conducted. The only correct temperature field across the TTR is that which can be represented by the interpolation functions employed in the BEM code. Further, incorrect solutions can also be generated if the TTR is too thin. The nature of the deformation at the hot spot location depends on whether the thermal boundary condition on the outer surface of the hot leg is one of constant temperature or adiabatic. The analysis shows that at the location of the hot spot on the inner surface large compressive stresses can be established. On the outer surface at the same location, large tensile stresses can be established. The presence of these large stress elevations in the  More>>
Authors:
Bains, R S; Sugimoto, Jun [1] 
  1. Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
Publication Date:
Aug 01, 1994
Product Type:
Technical Report
Report Number:
JAERI-Research-94-007
Reference Number:
SCA: 210200; PA: JPN-94:011233; EDB-95:007399; SN: 95001296267
Resource Relation:
Other Information: PBD: Aug 1994
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; PIPES; HOT SPOTS; THERMAL STRESSES; PWR TYPE REACTORS; THREE-DIMENSIONAL CALCULATIONS; THERMOELASTICITY; BOUNDARY ELEMENT METHOD; NUMERICAL SOLUTION; TENSILE PROPERTIES; SURFACES; 210200; POWER REACTORS, NONBREEDING, LIGHT-WATER MODERATED, NONBOILING WATER COOLED
OSTI ID:
10102309
Research Organizations:
Japan Atomic Energy Research Inst., Tokyo (Japan)
Country of Origin:
Japan
Language:
English
Other Identifying Numbers:
Other: ON: DE95722075; TRN: JP9411233
Availability:
OSTI; NTIS; INIS
Submitting Site:
JPN
Size:
75 p.
Announcement Date:
Jun 30, 2005

Technical Report:

Citation Formats

Bains, R S, and Sugimoto, Jun. 3-D thermal stress analysis of hot spots in reactor piping using BEM. Japan: N. p., 1994. Web.
Bains, R S, & Sugimoto, Jun. 3-D thermal stress analysis of hot spots in reactor piping using BEM. Japan.
Bains, R S, and Sugimoto, Jun. 1994. "3-D thermal stress analysis of hot spots in reactor piping using BEM." Japan.
@misc{etde_10102309,
title = {3-D thermal stress analysis of hot spots in reactor piping using BEM}
author = {Bains, R S, and Sugimoto, Jun}
abstractNote = {A three-dimensional steady state thermoelastic analysis has been conducted on the hot leg of a pressurized water reactor(PWR) containing localized hot spots resulting from fission product aerosol deposition occurring during a hypothetical severe accident. The boundary element method (BEM) of numerical solution was successfully employed to investigate the structural response of the hot leg. Convergence of solution can be realized provided sufficiently large number of elements are employed and correct modelling of the temperature transition region (TTR) adjacent to the hot spot on the inner surface is conducted. The only correct temperature field across the TTR is that which can be represented by the interpolation functions employed in the BEM code. Further, incorrect solutions can also be generated if the TTR is too thin. The nature of the deformation at the hot spot location depends on whether the thermal boundary condition on the outer surface of the hot leg is one of constant temperature or adiabatic. The analysis shows that at the location of the hot spot on the inner surface large compressive stresses can be established. On the outer surface at the same location, large tensile stresses can be established. The presence of these large stress elevations in the vicinity of the hot spot could be detrimental to the integrity of the hot leg. The tensile stresses are extremely important since they can act as sites of crack initiation and subsequent propagation. Once a crack propagates through the thickness, leak worthiness of the hot leg comes into question. Consequently, additional analysis incorporating the effects of plasticity and temperature dependence of the material properties must be conducted to ascertain the integrity of the hot leg. (J.P.N.).}
place = {Japan}
year = {1994}
month = {Aug}
}