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Fracture mechanics assessment of surface and sub-surface cracks in the RPV under non-symmetric PTS loading

Abstract

One of the most severe loading conditions of a reactor pressure vessel (rpv) under operation is the loss of coolant accident (LOCA) condition. Cold water is injected through nozzles in the downcomer of the rpv, while the internal pressure may remain at a high level. Complex thermal hydraulic situations occur and the fluid and downcomer temperatures as well as the fluid to wall heat transfer coefficient at the inner surface are highly non-linear. Due to this non-symmetric conditions, the problem is investigated by three-dimensional non-linear finite element analyses, which allow for an accurate assessment of the postulated flaws. Transient heat transfer analyses are carried out to analyze the effect of non-symmetrical cooling of the inner surface of the pressure vessel. In a following uncoupled stress analysis the thermal shock effects for different types of defects, surface flaws and sub-surface flaws are investigated for linear elastic and elastic-plastic material behaviour. The obtained fracture parameters are calculated along the crack fronts. By a fast fracture analysis the fracture parameters at different positions along the crack front are compared to the material resistance. Safety margins are pointed out in an assessment diagram of the fracture parameters and the fracture resistance versus the transient  More>>
Authors:
Keim, E; Shoepper, A; Fricke, S [1] 
  1. Siemens AG Unternehmensbereich KWU, Erlangen (Germany)
Publication Date:
Sep 01, 1997
Product Type:
Conference
Report Number:
IWG-LMNPP-96/1; CONF-9705163-
Reference Number:
SCA: 220200; PA: AIX-28:059459; EDB-97:116698; SN: 97001844453
Resource Relation:
Conference: IAEA specialists` meeting on methodology for pressurized thermal shock evaluation, Esztergom (Hungary), 5-8 May 1997; Other Information: PBD: 1997; Related Information: Is Part Of Methodology for pressurized thermal shock evaluation. Proceedings of the IAEA specialists meeting. Working material; PB: 457 p.
Subject:
22 NUCLEAR REACTOR TECHNOLOGY; PRESSURE VESSELS; CRACKS; EVALUATION; FRACTURE MECHANICS; LOSS OF COOLANT; SURFACES; THERMAL SHOCK
OSTI ID:
519615
Research Organizations:
International Atomic Energy Agency, Vienna (Austria). International Working Group on Life Management of Nuclear Power Plants
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ON: DE97640092; TRN: XA9744637059459
Availability:
INIS; OSTI as DE97640092
Submitting Site:
INIS
Size:
pp. 235-246
Announcement Date:

Citation Formats

Keim, E, Shoepper, A, and Fricke, S. Fracture mechanics assessment of surface and sub-surface cracks in the RPV under non-symmetric PTS loading. IAEA: N. p., 1997. Web.
Keim, E, Shoepper, A, & Fricke, S. Fracture mechanics assessment of surface and sub-surface cracks in the RPV under non-symmetric PTS loading. IAEA.
Keim, E, Shoepper, A, and Fricke, S. 1997. "Fracture mechanics assessment of surface and sub-surface cracks in the RPV under non-symmetric PTS loading." IAEA.
@misc{etde_519615,
title = {Fracture mechanics assessment of surface and sub-surface cracks in the RPV under non-symmetric PTS loading}
author = {Keim, E, Shoepper, A, and Fricke, S}
abstractNote = {One of the most severe loading conditions of a reactor pressure vessel (rpv) under operation is the loss of coolant accident (LOCA) condition. Cold water is injected through nozzles in the downcomer of the rpv, while the internal pressure may remain at a high level. Complex thermal hydraulic situations occur and the fluid and downcomer temperatures as well as the fluid to wall heat transfer coefficient at the inner surface are highly non-linear. Due to this non-symmetric conditions, the problem is investigated by three-dimensional non-linear finite element analyses, which allow for an accurate assessment of the postulated flaws. Transient heat transfer analyses are carried out to analyze the effect of non-symmetrical cooling of the inner surface of the pressure vessel. In a following uncoupled stress analysis the thermal shock effects for different types of defects, surface flaws and sub-surface flaws are investigated for linear elastic and elastic-plastic material behaviour. The obtained fracture parameters are calculated along the crack fronts. By a fast fracture analysis the fracture parameters at different positions along the crack front are compared to the material resistance. Safety margins are pointed out in an assessment diagram of the fracture parameters and the fracture resistance versus the transient temperature at the crack tip position. (author). 4 refs, 10 figs.}
place = {IAEA}
year = {1997}
month = {Sep}
}