Effect of Thermal Stratification on Full-Cone Spray Performance in Reactor Containment for a Scaled Scenario

2014 ◽  
Author(s):  
Sidharth Paranjape ◽  
Guillaume Mignot ◽  
Domenico Paladino
Keyword(s):  
Thermal Stratification ◽  
Nuclear Reactor ◽  
Initial Conditions ◽  
Fluid Temperature ◽  
Spray Nozzle ◽  
Mass Spectrometers ◽  
Spray System ◽  
Nozzle Configuration ◽  
Paul Scherrer ◽  
Mixing Of Gases

The results of an experimental study on the nuclear reactor containment spray system are presented. Depending on the initial conditions, the spray nozzle configuration and flow rates, the spray may cause higher hydrogen concentration during depressurization due to steam condensation, or it may erode the hydrogen stratification by enhanced mixing. To investigate these phenomena, the tests are performed using a full-cone spray nozzle in PANDA facility at Paul Scherrer Institut, Switzerland. Temporal evolution and spatial distribution of the fluid temperature and the fluid concentrations are measured using thermocouples and mass spectrometers. Two tests are performed with initial vessel wall temperatures of 105°C and 135°C, which create condensing and non-condensing environments respectively. The different initial conditions lead to different density stratifications. The effect of these different density stratification on the flow patterns and mixing of gases in the vessels due to the action of the spray is revealed by these tests.

THERMAL STRATIFICATION IN NUCLEAR REACTOR PIPING SYSTEM

Equipment ◽  
2006 ◽  
Author(s):  
H. C. Rezende ◽  
M. A. Navarro ◽  
A. A. C. dos Santos
Keyword(s):  
Thermal Stratification ◽  
Nuclear Reactor ◽  
Piping System

SIMULASI KARAKTERISTIK ALIRAN DAN SUHU FLUIDA PENDINGIN (H2O) PADA TERAS REAKTOR NUKLIR SMR (SMALL MODULAR REACTOR)

ROTASI ◽  
2013 ◽  
Vol 15 (4) ◽  
pp. 33
Author(s):  
Anwar Ilmar Ramadhan ◽  
Indra Setiawan ◽  
M. Ivan Satryo
Keyword(s):  
Fluid Flow ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Heat Removal ◽  
Axial Direction ◽  
Operating Conditions ◽  
Fluid Temperature ◽  
Wide Range ◽  
Fuel Reactor ◽  
Performance Of Heat Transfer

Safety is an issue that is of considerable concern in the design, operation and development of a nuclear reactor. Therefore, the method of analysis used in all these activities should be thorough and reliable so as to predict a wide range of operating conditions of the reactor, both under normal operating conditions and in the event of an accident. Performance of heat transfer to the cooling of nuclear fuel, reactor safety is key. Poor heat removal performance would threaten the integrity of the fuel cladding which could further impact on the release of radioactive substances into the environment in an uncontrolled manner to endanger the safety of the reactor workers, the general public, and the environment. This study has the objective is to know is profile contour of fluid flow and the temperature distribution pattern of the cooling fluid is water (H2O) in convection in to SMR reactor with fuel sub reed arrangement of hexagonal in forced convection. In this study will be conducted simulations on the SMR reactor core used sub channel hexagonal using CFD (Computational Fluid Dynamics) code. And the results of this simulation look more upward (vector of fluid flow) fluid temperature will be warm because the heat moves from the wall to the fluid heater. Axial direction and also looks more fluid away from the heating element temperature will be lower.

Development of Ultrasonic Temperature Sensors for Ultra-High Temperature Measurement in Nuclear Reactor Vessel

2002 ◽  
Author(s):  
Kil-Mo Koo ◽  
Kwang-Soon Ha ◽  
Rae-Joon Park ◽  
Sang-Baik Kim ◽  
Hee-Dong Kim ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Measurement ◽  
Optimization Design ◽  
Nuclear Reactor ◽  
Initial Conditions ◽  
Measurement Techniques ◽  
Gap Formation ◽  
Melt Temperature ◽  
Infrared Thermometry ◽  
High Temperature Measurement

The temperature measurement of a very high temperature core melt is of importance in LAVA (lower-plenum Arrested Vessel Attack) experiment in which gap formation between core melt and the reactor lower head, and the effect of the gap on thermal behavior are to be measured. The existing temperature measurement techniques have some problems, where the thermocouple, one of the contact methods, is restricted to under 2000°C, and the infrared thermometry, one of the non-contact methods, is unable to measure an internal temperature and very sensitive to the interference from reacted gases. So, in order to solve these problems, the delay time of ultrasonic wavelets due to high temperature is suggested. One of the key initial conditions to be measured in LAVA is the initial corium melt temperature. To measure it, the LAVA measurement group has developed several kinds of UTS’s. As a first stage, a molten material temperature was measured up to 2314°C. Also, the optimization design of the UTS (ultrasonic temperature sensor) with persistence at the high temperature was suggested in this paper. And the utilization of the theory suggested in this paper and the efficiency of the developed system are certified by performing experiments.

Experimental Investigation on Rapid Evaporation of High-Pressure Liquids due to Depressurization

2012 ◽  
Author(s):  
Qiaoling Zhang ◽  
Qincheng Bi ◽  
Zesen Nie ◽  
Jun Liang ◽  
Yajun Guo ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
High Speed ◽  
Initial Conditions ◽  
Initial Pressure ◽  
Fluid Temperature ◽  
Shape Variation ◽  
Nitrogen Gas ◽  
Test Vessel ◽  
Variation Characteristics

This paper reports an experimental investigation of rapid evaporation process of high-pressure ethanol liquid during depressurization. The study focused on pressure and temperature transients with the influence of different initial conditions, and the shape variation was recorded via a high speed camera. During an experiment, the ethanol liquid was contained in a small round tube with a diameter 10mm in the test vessel, and a thermocouple was put within the fluid which was used to measure the fluid temperature during the depressurization. The predetermined pressure was provided by the high-pressure nitrogen gas, and the process of quick depressurization was started by opening the magnetic valve, which was connected with the test vessel. The transitions of the pressure and the fluid temperature were recorded by the NI data collection system. According to the experimental results, during the fast pressure drop, with the same initial temperature and other test conditions, the higher the initial pressure is, the faster the liquid temperature decreases, and the lower the minimum temperature reaches. In addition, the effect of initial fluid conditions, initial environmental pressure on temperature transition and so on are summed up and are experimentally analyzed on the fluid temperature change under the same test equipment. Also, the variation characteristics of kerosene fluid were compared with ethanol liquid under the same experiment conditions.

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.

scholarly journals Basic analysis on heat transfer phenomena in natural circulation for liquid sodium

2021 ◽  
Vol 2072 (1) ◽  
pp. 012012
Author(s):  
R Wulandari ◽  
S Permana ◽  
Suprijadi
Keyword(s):  
Heat Transfer ◽  
Nuclear Reactor ◽  
Cooling System ◽  
Natural Circulation ◽  
Liquid Sodium ◽  
Navier Stokes ◽  
Circulation System ◽  
Fluid Temperature ◽  
Navier Stokes Equation ◽  
Basic Equations

Abstract Natural convention, the heat transfer on fluid due to density differences that can be caused by differences in fluid temperature. One example application of natural convection is cooling system, such as nuclear reactor cooling system. The purpose of this study is to analysis the basic characteristic heat transfer of sodium liquid in the natural circulation system for steady state analysis and transient characteristic with Finite Element Method. The selected module is the Non-Isothermal FLow (NITF) module. This module is a combination of three basic equations, namely the continuity equation, the Navier-Stokes equation, and the dynamic equation of heat transfer in fluid. The simulation model measures 1.5 x 2 (m) with sodium liquid (Na) as a fluid.

Dependence of the temperature distribution in the vortex tube on the geometry of the swirler

2017 ◽  
Vol 12 (2) ◽  
pp. 174-179 ◽  
Author(s):  
C.I. Mikhaylenko
Keyword(s):  
Mathematical Model ◽  
Temperature Distribution ◽  
Computational Modeling ◽  
Thermal Stratification ◽  
Vortex Tube ◽  
Initial Conditions ◽  
Size And Shape ◽  
Shape And Size

Modeling of the vortex tube for several variants of the size and shape of inlets of the swirl is carried out. A mathematical model of the process is written. Computational modeling was based on the LES method using the PIMPLE algorithm in the OpenFOAM computational package. Considerable attention was paid to using uniform orthogonalized meshes, while the shape and size of the swirl of the swirl was determined by the feature of the mesh constructed. It is shown that, under certain initial conditions, the effect of thermal stratification can be inversed for some forms of the swirler.

APPLICATION OF INFORMATION TECHNOLOGY FOR MODELING THE CONTROL DYNAMICS OF A NUCLEAR REACTOR ZONING ON THE VERTICAL AXIS

2021 ◽  
Vol 5 ◽  
pp. 45-56
Author(s):  
Valery Severyn ◽  
◽  
Elena Nikulina ◽  
Keyword(s):  
Information Technology ◽  
Nonlinear Systems ◽  
Differential Equations ◽  
Control Systems ◽  
Nuclear Reactor ◽  
Initial Conditions ◽  
Control Object ◽  
Vertical Axis ◽  
Integration Methods ◽  
Systems Of Differential Equations

The structure of information technology for modeling control systems, which includes a block of systems models, a module of integration methods and other program elements, is considered. To analyze the dynamics of control of a nuclear reactor, programs of mathematical models of a WWER-1000 nuclear reactor of the V-320 series and its control systems in the form of nonlinear systems of differential equations in the Cauchy form have been developed. For the integration of nonlinear systems of differential equations, an algorithm of the system method of the first degree is presented. A mathematical model of a WWER-1000 reactor as a control object with division into zones along the vertical axis in relative variables of state is considered, the values of the constant parameters of the model and the initial conditions corresponding to the nominal mode are given. Using information technology for ten zones of the reactor, the system integration method was used to simulate the dynamics of control of a nuclear reactor. Graphs of neutron and thermal processes in the reactor core, as well as changes in the axial offset when the reactor load is dumped under the influence of the movement of absorbing rods and an increase in the concentration of boric acid, are plotted. The analysis of dynamic processes of reactor control is carried out. The programs of integration methods and models of the WWER-1000 reactor of the V-320 series are included in the information technology to optimize the maneuvering modes of the reactor.

Study on the Design Methodology of Swirl Nozzle for Nuclear Reactor Pressurizer

2017 ◽  
Author(s):  
Xiong Cao ◽  
Zhiwei Ding
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Design Methodology ◽  
Nuclear Reactor ◽  
Internal Flow ◽  
Spray Angle ◽  
Spray Nozzle ◽  
Reactor Coolant ◽  
Atomization Performance ◽  
Coolant System

Pressurizer is one of the most important components in reactor coolant system of a nuclear power plant, which operates normally at pressure of 15.4 MPa and temperature of 345°C[1]. The main function of pressurizer is to regulate the pressure in the reactor coolant system by either cooling the steam or heating the saturated water in its upper zone. When the pressure in the reactor coolant system increases, it will distribute cold water to decrease its temperature and pressure through atomizing the reactor coolant with swirl spray nozzle in pressurizer. Swirl nozzle is the key part of pressurizer with swirl structure of full cone spray pattern, and the atomization performance include drop size, spray angle and distribution, also it is characterized by huge flow rate and low pressure drop, and its atomization performance decides the quality of pressure control of the reactor coolant system. To enhance the independent design level of both pressurizer and cooling system, it’s necessary to study the atomization performance of swirl nozzle for nuclear reactor pressurizer. Aimed at improving atomization performance of swirl spray nozzle, the structure design methodology of nuclear reactor pressurizer was studied systematically in three aspects including theory design, numerical simulation and test confirm in this thesis. Through designing the swirl nozzle structure according to similar design formula of spray nozzle in theory, especially studying the influence of different structures that mainly include internal swirl structure on internal flow field of swirl nozzles, the primary structure parameters of swirl nozzle were confirmed. Then, through numerical simulation of the internal flow field, flow rate and pressure drop, and swirl core structure of the swirl nozzle (by building physical model and mathematic model according to the spray nozzle structure), the atomization performance of the nozzle was analyzed. On this basis, the typical swirl nozzle was designed and tested, which included spray angle, flow rate as well as pressure drop tests, and spray drop tests, and the applicability of the computational fluid dynamics (CFD) method was verified when it was applied in swirl nozzle design. Finally, the design method of swirl nozzle with deep groove of swirl core for pressurizer was put forward. Through this studying of theoretical calculation, numerical simulating and test, the correlation between the structural parameters of swirl nozzle and atomization performance was achieved, meanwhile design, analysis and test methods of spray nozzle with low pressure drop and huge flow rate were established. It is helpful to realize the independent design of pressurizer’s swirl nozzle and even to put forward the design methodology of pressurizer’s swirl nozzle with our own characteristic.

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