Test Methods for Accumulated Deposition in a Steam Generator Tube

10.1520/d3483 ◽  
2008 ◽  
Author(s):  
Keyword(s):  
Steam Generator ◽  
Test Methods ◽  
Steam Generator Tube

Measurement of Steam-Generator Tube Damping Caused by Anti-Vibration-Bar Supports

2021 ◽  
Author(s):  
Bruce A. W. Smith ◽  
Paul Feenstra ◽  
Michael Liu
Keyword(s):  
Steam Generator ◽  
Low Frequency ◽  
Test Methods ◽  
Squeeze Film ◽  
Published Data ◽  
Single Pair ◽  
Design Guideline ◽  
Steam Generator Tube ◽  
Position Sensing ◽  
And Control

Abstract In 2013, Atomic Energy of Canada Limited (now Canadian Nuclear Laboratories) took vibration measurements to examine low-frequency damping associated with tube vibration parallel to anti-vibration bar supports. These tests were performed to better understand and control in-plane fluidelastic instability of tubes in the U-bend region of recirculating steam generators. In the tests, the damping ratios of a single steam generator tube vibrating parallel to a single pair of anti-vibration bars were measured using both a log-decrement and a power-based method. Non-contacting excitation and position-sensing techniques were employed to improve accuracy. The tests examined the effects of fluid (water or air), natural frequency, gap width, preload, and vibration normal to the bars. Additional tests were also done using a drilled-hole support and without supports to allow validation against previously published work. Most of the tests were performed in water. This paper describes the tests including the test apparatus, test methods, and analysis techniques. A summary of the results is presented. These results show that the damping ratios measured without any supports and with a drilled-hole support are consistent with previously published data. Contrary to an existing design guideline, the anti-vibration bars resulted in no significant additional viscous or squeeze-film damping for vibration parallel to the bars. The results also showed that anti-vibration bars can introduce significant in-plane Coulomb-type damping because of friction and impacting.

scholarly journals Analysis of the Accelerator-Driven System Fuel Assembly during the Steam Generator Tube Rupture Accident

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1818
Author(s):  
Di-Si Wang ◽  
Bo Liu ◽  
Sheng Yang ◽  
Bin Xi ◽  
Long Gu ◽  
...  
Keyword(s):  
Fuel Assembly ◽  
Steam Generator ◽  
Metal Flow ◽  
Maximum Temperature ◽  
Steam Generator Tube ◽  
Driven System ◽  
Fuel Assemblies ◽  
Accelerator Driven System ◽  
The Impact ◽  
Steam Bubble

China is developing an ADS (Accelerator-Driven System) research device named the China initiative accelerator-driven system (CiADS). When performing a safety analysis of this new proposed design, the core behavior during the steam generator tube rupture (SGTR) accident has to be investigated. The purpose of our research in this paper is to investigate the impact from different heating conditions and inlet steam contents on steam bubble and coolant temperature distributions in ADS fuel assemblies during a postulated SGTR accident by performing necessary computational fluid dynamics (CFD) simulations. In this research, the open source CFD calculation software OpenFOAM, together with the two-phase VOF (Volume of Fluid) model were used to simulate the steam bubble behavior in heavy liquid metal flow. The model was validated with experimental results published in the open literature. Based on our simulation results, it can be noticed that steam bubbles will accumulate at the periphery region of fuel assemblies, and the maximum temperature in fuel assembly will not overwhelm its working limit during the postulated SGTR accident when the steam content at assembly inlet is less than 15%.

Time Domain Simulation of the Vibration of a Steam Generator Tube Subjected to Fluidelastic Forces Induced by Two-Phase Cross-Flow

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Téguewindé Sawadogo ◽  
Njuki Mureithi
Keyword(s):  
Steam Generator ◽  
Two Phase Flow ◽  
Work Rate ◽  
Fretting Wear ◽  
Phase Flow ◽  
Reference Case ◽  
Two Phase ◽  
Steam Generator Tube ◽  
Wide Range ◽  
Instability Regime

Having previously verified the quasi-steady model under two-phase flow laboratory conditions, the present work investigates the feasibility of practical application of the model to a prototypical steam generator (SG) tube subjected to a nonuniform two-phase flow. The SG tube vibration response and normal work-rate induced by tube-support interaction are computed for a range of flow conditions. Similar computations are performed using the Connors model as a reference case. In the quasi-steady model, the fluid forces are expressed in terms of the quasi-static drag and lift force coefficients and their derivatives. These forces have been measured in two-phase flow over a wide range of void fractions making it possible to model the effect of void fraction variation along the tube span. A full steam generator tube subjected to a nonuniform two-phase flow was considered in the simulations. The nonuniform flow distribution corresponds to that along a prototypical steam-generator tube based on thermal-hydraulic computations. Computation results show significant and important differences between the Connors model and the two-phase flow based quasi-steady model. While both models predict the occurrence of fluidelastic instability, the predicted pre-instability and post instability behavior is very different in the two models. The Connors model underestimates the flow-induced negative damping in the pre-instability regime and vastly overestimates it in the post instability velocity range. As a result the Connors model is found to underestimate the work-rate used in the fretting wear assessment at normal operating velocities, rendering the model potentially nonconservative under these practically important conditions. Above the critical velocity, this model largely overestimates the work-rate. The quasi-steady model on the other hand predicts a more moderately increasing work-rate with the flow velocity. The work-rates predicted by the model are found to be within the range of experimental results, giving further confidence to the predictive ability of the model. Finally, the two-phase flow based quasi-steady model shows that fluidelastic forces may reduce the effective tube damping in the pre-instability regime, leading to higher than expected work-rates at prototypical operating velocities.

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