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Impacts and fluid-structure interaction in pressurized water reactor safety analysis

Schumann, U. (1982) Impacts and fluid-structure interaction in pressurized water reactor safety analysis. Nuclear Engineering and Design, 69, pp. 313-326. doi: 10.1016/0029-5493(82)90180-7.


Official URL: http://www.elsevier.com/wps/find/journaldescription.cws_home/505661/description#description


A numerical method is described for the analysis of coupled three-dimensional fluid-structure motion with impacts between structural parts at rigid or flexible supports with small clearances. The method is used for the analysis of the blowdown loadings and the response of internal structures in the vessel of a pressurized water reactor (PWR) in the hypothetical event of a sudden break of a coolant inlet pipe. The method is a generalization of the existing code FLUX which simulates the three-dimensional fluid-structure motion by means of an implicit time integration scheme. The additional supports with clearances are taken into account by applying support forces to the freely moving fluid-structure system. The forces are determined such that the kinematic constraints are enforced at each time step. Numerically, these forces are determined efficiently using a precomputed influence matrix which defines the dynamic displacement per time step at each support due to a unit force at each other support. According to the actually “active” supports the relevant influence matrix in constructed. Energy is conserved for rigid supports and for supports which are so flexible that the impact time is large in comparison to the time steps. Treatment of plastic supports is possible. An application of the new method is demonstrated by analysis of the core barrel motion in a PWR with and without impacts at the lower core barrel edge and at the upper flange. The results show the large effects of such impacts in changing the global motions. Large local impact forces and accelerations appear. The interaction with the fluid reduces these loads. By proper design of the supports the resultant stresses can be minimized. Thus the method can be used to demonstrate and enlarge nuclear reactor safety.

Item URL in elib:https://elib.dlr.de/53410/
Document Type:Article
Title:Impacts and fluid-structure interaction in pressurized water reactor safety analysis
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Schumann, U.Kernforschungszentrum KarlsruheUNSPECIFIEDUNSPECIFIED
Journal or Publication Title:Nuclear Engineering and Design
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:No
Page Range:pp. 313-326
Keywords:numerical method, fluid-structure, PWR
HGF - Research field:other
HGF - Program:other
HGF - Program Themes:other
DLR - Research area:no assignment
DLR - Program:no assignment
DLR - Research theme (Project):no assignment
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics
Deposited By: Freund, Jana
Deposited On:26 Nov 2008
Last Modified:31 Jul 2019 19:21

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