scholarly journals Experimental Investigation and Computational Validation of Thermal Stratification in Piping Systems of PWR Reactors

10.5772/52614 ◽  
2013 ◽  
Author(s):  
Hugo Cesar ◽  
Andre Augusto Campagnole dos Santos ◽  
Moyses Alberto ◽  
Amir Zacarias ◽  
Elizabete Jordao
Keyword(s):  
Experimental Investigation ◽  
Thermal Stratification ◽  
Piping Systems ◽  
Computational Validation

Prediction of Fluid Temperatures From Measurements of Outside Wall Temperatures in Pipes

1994 ◽  
Vol 116 (2) ◽  
pp. 179-187 ◽  
Author(s):  
M. Guyette
Keyword(s):  
Temperature Measurement ◽  
Wall Temperature ◽  
Industrial Application ◽  
Thermal Stratification ◽  
Transfer Functions ◽  
Fluid Temperature ◽  
Convolution Integral ◽  
Thermal Transients ◽  
Points Of Interest ◽  
Piping Systems

The monitoring of the fatigue induced by thermal transients in thick-walled structures becomes more and more currently performed, mainly on equipment the failure of which could present severe implications on the environment. The easiest way of performing this monitoring is by use of Green’s functions in a convolution integral of the measured fluid temperatures to assess the stresses at the points of interest. Numerous cases, however, exist where the fluid temperatures are not available and only an outside wall temperature measurement is feasible. This paper describes the development and the industrial application of the so-called “inverse” transfer functions to predict the evolution of the fluid temperature from measurements of the metal temperature either at the outside or in the wall of the considered equipment. Some applications are shown for the particular case of the thermal stratification in piping systems.

A New Method to Weaken Thermal Stratification Phenomena in Pipes of Nuclear Power Plant

2013 ◽  
Author(s):  
Shengfei Wang ◽  
Yuxin Pang ◽  
Xiaojing Li ◽  
Dandan Fu ◽  
Yang Li ◽  
...  
Keyword(s):  
Thermal Stratification ◽  
Nuclear Power ◽  
Thermal Stresses ◽  
Heat Pipes ◽  
New Method ◽  
Simple Experiment ◽  
Pressurized Water ◽  
Piping Systems ◽  
Surge Line ◽  
Water Reactors

Thermal stratification phenomena are observed in piping systems of pressurized water reactors, especially in the pressurizer surge line. As a result of the thermal stratification induced thermal stresses, fatigue problems can occur in the pipework. US NRC requirements have also identified flow stratification in surge lines as a phenomenon that must be considered in the design basis of surge lines. In this paper, a new method to reduce thermal stratification is proposed. As we all know, heat pipe is a simple device with no moving parts and can transfer large quantities of heat over fairly large distance. The new method is that using heat pipes to weaken the thermal stratification. In order to validate the new method, a simple experiment and theoretical analysis was taken. The results show that, the temperature difference of thermal stratification with heat pipes is smaller than the stratification without heat pipes. A design scheme was also given at the end of paper.

CFD Analysis of Thermal Stratification Phenomena in the RNS Suction Line of a Gen-III Nuclear Power Plant

2013 ◽  
Author(s):  
Yan Li ◽  
Daogang Lu ◽  
Zhigang Wang ◽  
Jian Wu ◽  
Fengyun Yu
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Thermal Stratification ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Heat Removal ◽  
Radial Temperature ◽  
Piping Systems ◽  
Suction Line ◽  
Power Operation

Thermal stratification phenomena in piping systems of nuclear power plant would threaten the structural integrity of pipes, which are caused by the significant change of water density with temperature. To provide temperature gradients for the stress analysis of Normal heat Removal System (RNS) suction line of a Gen-III nuclear power plant, the relevant thermal stratification phenomena are analyzed by CFD in this paper. Cases without leakage (normal power operation) and with leakage are both studied. The results show that the first portion of pipe (one meter or so) near the hot leg is isothermal for normal power operation due to the penetrating flow. In the remaining portion, the radial temperature drops are of the order of 20∼27 K for no leakage case. For the leakage case, the radial temperature drops are 23 K or less, which are relatively smaller than those for the no leakage case due to the net hot flow from the hot leg to the valve.

Algebraic Turbulent Heat Flux Model for Prediction of Thermal Stratification in Piping Systems

2013 ◽  
Vol 181 (1) ◽  
pp. 144-156
Author(s):  
M. Pellegrini ◽  
H. Endo ◽  
E. Merzari ◽  
H. Ninokata
Keyword(s):  
Heat Flux ◽  
Thermal Stratification ◽  
Turbulent Heat Flux ◽  
Turbulent Heat ◽  
Piping Systems ◽  
Flux Model ◽  
Heat Flux Model

Experimental investigation of thermal stratification subject to multi-species ullage

2020 ◽  
Vol 45 (1) ◽  
pp. 46-51
Author(s):  
Mebin Abraham Cherian ◽  
Jeswin Joseph ◽  
Gagan Agrawal ◽  
Deepak K. Agarwal ◽  
T. John Tharakan ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Thermal Stratification
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