Elimination of Flow-Rate Fluctuations in the Core of the FRJ-2 Research Reactor and Its Usefulness for Reactor Operation

1977 ◽  
Vol 34 (3) ◽  
pp. 369-375
Author(s):  
Johannes Wolters ◽  
Manfred Nickel
Keyword(s):  
Flow Rate ◽  
Research Reactor ◽  
Reactor Operation ◽  
The Core

scholarly journals Estimation of Fuel Burnup Rate for Core Conversion for the Nigeria Research Reactor-1 (NIRR-1) Fueled With 19.75% Enriched UO2 USING VENTURE PC Code

2020 ◽  
pp. 42-49
Author(s):  
J. A. Rabba ◽  
M. Y. Onimisi ◽  
D. O. Samson
Keyword(s):  
Uranium Dioxide ◽  
Research Reactor ◽  
Fuel Burnup ◽  
Reactor Operation ◽  
The Core ◽  
Computer Codes ◽  
Enriched Uranium ◽  
Conversion Study ◽  
Good Agreement

A standardized burnup analysis using VENTURE-PC computer codes system has been performed for the core conversion study of Nigeria Research Reactor-1. The result obtained from this analysis showed that the mass of Uranium decreases with increase in the number of days of reactor operation while the quantity of Plutonium continues to build up linearly. The buildup of the fissile isotope in the Low Enriched Uranium (LEU) core is very much greater than in the Highly Enriched Uranium (HEU) core. The quantity of Uranium-235 consumed and the amount of Plutonium-239 produce in the core of the reactor were 13.95 g and 0.766745 g respectively for the period of 11 years of reactor operation which is in good agreement with other literatures. This results obtained showed that uranium dioxide (UO2) fuel is a potential material for future Low Enriched Uranium (LEU) core conversion of Nigeria Research Reactor.

scholarly journals Prediction of Flow and Temperature Distributions in a High Flux Research Reactor Using the Porous Media Approach

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Shanfang Huang ◽  
Daxin Gong ◽  
Chao Li ◽  
Xiaoyu Guo ◽  
Guanbo Wang ◽  
...  
Keyword(s):  
Porous Media ◽  
Flow Rate ◽  
Research Reactor ◽  
Flow Direction ◽  
Coolant Temperature ◽  
Rate Variation ◽  
High Flux ◽  
Fuel Temperature ◽  
The Core ◽  
Porous Media Model

High thermal neutron fluxes are needed in some research reactors and for irradiation tests of materials. A High Flux Research Reactor (HFRR) with an inverse flux trap-converter target structure is being developed by the Reactor Engineering Analysis Lab (REAL) at Tsinghua University. This paper studies the safety of the HFRR core by full core flow and temperature calculations using the porous media approach. The thermal nonequilibrium model is used in the porous media energy equation to calculate coolant and fuel assembly temperatures separately. The calculation results show that the coolant temperature keeps increasing along the flow direction, while the fuel temperature increases first and decreases afterwards. As long as the inlet coolant mass flow rate is greater than 450 kg/s, the peak cladding temperatures in the fuel assemblies are lower than the local saturation temperatures and no boiling exists. The flow distribution in the core is homogeneous with a small flow rate variation less than 5% for different assemblies. A large recirculation zone is observed in the outlet region. Moreover, the porous media model is compared with the exact model and found to be much more efficient than a detailed simulation of all the core components.

scholarly journals Expanded Microchannel Heat Exchanger: Finite Difference Modeling

Designs ◽  
2021 ◽  
Vol 5 (4) ◽  
pp. 58
Author(s):  
David Denkenberger ◽  
Joshua M. Pearce ◽  
Michael Brandemuehl ◽  
Mitchell Alverts ◽  
John Zhai
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Finite Difference ◽  
Flow Rate ◽  
Experimental Results ◽  
Low Flow ◽  
Difference Model ◽  
The Core ◽  
Finite Difference Model ◽  
Flow Maldistribution

A finite difference model of a heat exchanger (HX) considered maldistribution, axial conduction, heat leak, and the edge effect, all of which are needed to model a high effectiveness HX. An HX prototype was developed, and channel height data were obtained using a computerized tomography (CT) scan from previous work along with experimental results. This study used the core geometry data to model results with the finite difference model, and compared the modeled and experimental results to help improve the expanded microchannel HX (EMHX) prototype design. The root mean square (RMS) error was 3.8%. Manifold geometries were not put into the model because the data were not available, so impacts of the manifold were investigated by varying the temperature conditions at the inlet and exit of the core. Previous studies have not considered the influence of heat transfer in the manifold on the HX effectiveness when maldistribution is present. With no flow maldistribution, manifold heat transfer increases overall effectiveness roughly as would be expected by the greater heat transfer area in the manifolds. Manifold heat transfer coupled with flow maldistribution for the prototype, however, causes a decrease in the effectiveness at high flow rate, and an increase in effectiveness at low flow rate.

scholarly journals THE THERMOHYDRAULIC ANALYSIS OF THE BANDUNG RESEARCH REACTOR CORE WITH PLATE TYPE FUEL ELEMENTS USING THE CFD CODE

2018 ◽  
Vol 20 (3) ◽  
pp. 123
Author(s):  
Reinaldy Nazar ◽  
Sudjatmi KA ◽  
Ketut Kamajaya
Keyword(s):  
Fuel Element ◽  
Surface Temperature ◽  
Forced Convection ◽  
Flow Rate ◽  
Research Reactor ◽  
Saturation Temperature ◽  
Cooling Flow ◽  
Fuel Elements ◽  
Type Fuel ◽  
Plate Type

Due to TRIGA fuel elements are no longer produced by General Atomic, it is necessary to find a solution so that the Bandung TRIGA 2000 reactor can still be operated. One solution is to replace the type of fuel elements. Study on using the MTR plate type fuel elements as used in RSG-GAS Serpong has been done for the Bandung TRIGA 2000. Based on the results of the study using CFD computer program, it is found that Bandung TRIGA 2000 with plate type fuel elements cannot be operated up to 2000 kW power by natural convection cooling mode. Therefore, the reactor must be cooled by forced convection. The analysis using forced convection showed that for cooling flow rate of 50 kg/s and various temperatures of 35oC, 35.5 oC and 36 oC, the surface temperature of the fuel element is between 110.37 oC and 111.27 oC. Meanwhile, the cooling water temperature in the corresponding position is between 61.03 oC and 61.95 oC. In this operation condition, the surface temperatures of fuel elements can approach the saturation temperature and nucleat boiling started to occur. Hence, the use of cooling flow rate entering core less than 50 kg/s should be avoided. The surface temperature of fuel elements decreased under saturation temperature if cooling flow rate is greater than 65 kg/s. The surface temperature of fuel elements is achieved at 96.65 oC and coolant temperature in the corresponding position was 54.38 oC. Keywords: Bandung research reactor, plate type fuel element, thermohydraulic, CFD code ANALISIS TERMOHIDROLIK TERAS REAKTOR RISET BANDUNG BERELEMEN BAKAR TIPE PELAT MENGGUNAKAN PROGRAM CFD. Mengingat tidak diproduksinya lagi elemen bakar TRIGA oleh General Atomic, maka perlu diusahakan suatu solusi agar reaktor TRIGA 2000 Bandung dapat tetap beroperasi. Salah satu solusi adalah dengan melakukan penggantian tipe elemen bakar. Pada studi ini telah dianalisis penggunaan elemen bakar tipe pelat yang sejenis dengan yang digunakan di RSG-GAS Serpong, untuk digunakankan pada teras reaktor TRIGA 2000 Bandung. Berdasarkan hasil penelitian yang telah dilakukan dengan menggunakan program komputer CFD, diketahui bahwa reaktor TRIGA berelemen bakar tipe pelat tidak dapat dioperasikan pada daya 2000 kW dengan menggunakan moda pendinginan konveksi alamiah seperti yang digunakan saat ini. Untuk kondisi ini, pendinginan dilakukan dengan moda pendinginan konveksi paksa. Hasil analisis konveksi paksa menunjukkan bahwa dengan menggunakan laju alir pendingin pompa 50 kg/s dan variasi temperatur pada 35 oC, 35,5 oC dan 36 oC, diperoleh temperatur permukaan pelat elemen bakar antara 110,37 oC – 111,27 oC dan temperatur pendinginnya pada posisi terkait antara 61,03 oC – 61,95 oC. Temperatur permukaan pelat elemen bakar ini mendekati temperatur saturasi dan tentunya telah mulai terjadi pendidihan inti, sehingga penggunaan laju alir pendingin masuk teras reaktor kurang dari 50 kg/s perlu dihindari. Temperatur permukaan pelat elemen bakar mulai menurun menjauhi temperatur saturasi jika digunakan laju alir pendingin lebih besar dari 65 kg/s, dengan temperatur permukaan pelat elemen bakar 96,65 oC dan temperatur pendinginnya pada posisi terkait 54,38 oC.Kata kunci: Reaktor riset Bandung, elemen bakar tipe pelat, termohidrolik, program CFD

scholarly journals Facile fabrication and characterization on alginate microfibres with grooved structure via microfluidic spinning

2019 ◽  
Vol 6 (5) ◽  
pp. 181928 ◽  
Author(s):  
Xiaolin Zhang ◽  
Lin Weng ◽  
Qingsheng Liu ◽  
Dawei Li ◽  
Bingyao Deng
Keyword(s):  
Flow Rate ◽  
Loss Modulus ◽  
Fibre Diameter ◽  
Morphological Structure ◽  
Flow Rates ◽  
Alginate Solution ◽  
The Core ◽  
Facile Fabrication ◽  
Fabrication And Characterization ◽  
Alginate Fibres

Alginate microfibres were fabricated by a simple microfluidic spinning device consisting of a coaxial flow. The inner profile and spinnability of polymer were analysed by rheology study, including the analysis of viscosity, storage modulus and loss modulus. The effect of spinning parameters on the morphological structure of fibres was studied by SEM, while the crystal structure and chemical group were characterized by FTIR and XRD, respectively. Furthermore, the width and depth of grooves on the fibres was investigated by AFM image analysis and the formation mechanism of grooves was finally analysed. It was illustrated that the fibre diameter increased with an increase in the core flow rate, whereas on the contrary of sheath flow rate. Fibre diameter exhibited an increasing tendency as the concentration of alginate solution increased, and the minimum spinning concentration of alginate solution was 1% with the finest diameter being around 25 µm. Importantly, the grooved structure was obtained by adjusting the concentration of solutions and flow rates, the depth of groove increased from 278.37 ± 2.23 µm to 727.52 ± 3.52 µm as the concentration varied from 1 to 2%. Alginate fibres, with topological structure, are candidates for wound dressing or the engineering tissue scaffolds.

scholarly journals On the Flow Behavior in Rotor-Stator System with Superposed Flow

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
Roger Debuchy ◽  
Fadi Abdel Nour ◽  
Gérard Bois
Keyword(s):  
Flow Rate ◽  
High Reynolds Number ◽  
Good Accuracy ◽  
Flow Behavior ◽  
Swirl Ratio ◽  
Rotating Fluid ◽  
Weighting Functions ◽  
The Core ◽  
Stationary Disc ◽  
High Reynolds

The flow between a rotor and a stator at high Reynolds number and small Ekman number is divided into three domains, two boundary layers adjacent to the discs separated by a central core. In the present work, a simple theoretical approach provides analytical solutions for the radial distribution of the core swirl ratio valid for a rotor-stator system with a superposed radial inflow rate. At first, the flow in the rotor boundary layer is assumed to behave as expressed by Owen and Rogers (1989) in the case of a turbulent flow on a rotating single disc. On the stator side, a necessary compensation flow rate must take place according to the conservation of mass. It is found that this compensation flow rate cannot be estimated with a good accuracy using the hypotheses of a stationary disc in a rotating fluid by Owen and Rogers (1989). Thus, two innovative weighting functions are tested, leading to new analytical laws relating the core swirl ratioKto the coefficient of flow rateCqrintroduced by Poncet et al. (2005). The adequacy between the theoretical solutions and numerous results of the literature is clearly improved and the discussion allows a better understanding of the flow behavior.

New Human-Machine Interface at VR-1 Training Reactor

2010 ◽  
Author(s):  
Martin Kropi´k ◽  
Jan Rataj ◽  
Monika Jurˇicˇkova´
Keyword(s):  
User Interface ◽  
Foreign Students ◽  
Nuclear Power ◽  
English Language ◽  
Reactor Power ◽  
Text Messages ◽  
Reactor Operation ◽  
The Core ◽  
Machine Interface ◽  
And Training

The paper describes a new human-machine (HMI) interface of the VR-1 nuclear training reactor at the Czech Technical University in Prague. The VR-1 reactor is primarily used for training of university students and future nuclear power plant staff. The new HMI was designed to meet functional, ergonomic and aesthetic requirements. It contains a PC with two monitors. The first alphanumerical monitor presents text messages about the reactor operation and status; next, the operator can enter commands to control the reactor operation. The second graphical monitor provides parameters of reactor operation and shows the course of the reactor power and other parameters. Furthermore, it is able to display the core configuration, perform reactivity calculations, etc. The HMI is also equipped with an alarm annunciator. Due to a high number of foreign students and visitors at the reactor, the Czech and English language versions of the user interface are available. The HMI contains also a History server which provides a very detailed storage and future presentation of the reactor operation. The new HMI improves safety and comfort of the reactor utilization, facilitates experiments and training, and provides better support for foreign visitors.

Effect of Thermal Stratification of Coolant in a Vertical Heated Channel

2002 ◽  
Author(s):  
Abolghasem Zare Shahneh
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Stratification ◽  
Research Reactor ◽  
Rate Versus ◽  
Heated Channel ◽  
Stratification Effect ◽  
Simplifying Assumptions ◽  
Linear Manner

In a vessel type low power research reactor having vertical fuel plates, while circulating pump is switched off, coolant (light water) would flow by natural convection. By using conservation equations, taking into account simplifying assumptions, coolant mass flow rate through the channel can be obtained. Due to the thermal stratification effect, coolant mass flow rate through the channel is shown to decrease. The present study shows that, assuming a linear thermal stratification, the variations of coolant mass flow rate versus stratification parameter behave in a non-linear manner. The aforementioned variations decrease down to 41%.

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