scholarly journals Pore Scale Thermal Hydraulics Investigations of Molten Salt Cooled Pebble Bed High Temperature Reactor with BCC and FCC Configurations

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Shixiong Song ◽  
Xiangzhou Cai ◽  
Yafen Liu ◽  
Quan Wei ◽  
Wei Guo
Keyword(s):  
Fluid Dynamics ◽  
High Temperature ◽  
Pressure Drop ◽  
Surface Temperature ◽  
Molten Salt ◽  
Thermal Hydraulics ◽  
Pore Scale ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
Body Center Cubic

The present paper systematically investigated pore scale thermal hydraulics characteristics of molten salt cooled high temperature pebble bed reactor. By using computational fluid dynamics (CFD) methods and employing simplified body center cubic (BCC) and face center cubic (FCC) model, pressure drop and local mean Nusselt number are calculated. The simulation result shows that the high Prandtl number molten salt in packed bed has unique fluid-dynamics and thermodynamic properties. There are divergences between CFD results and empirical correlations’ predictions of pressure drop and local Nusselt numbers. Local pebble surface temperature distributions in several default conditions are investigated. Thermal removal capacities of molten salt are confirmed in the case of nominal condition; the pebble surface temperature under the condition of local power distortion shows the tolerance of pebble in extreme neutron dose exposure. The numerical experiments of local pebble insufficient cooling indicate that in the molten salt cooled pebble bed reactor, the pebble surface temperature is not very sensitive to loss of partial coolant. The methods and results of this paper would be useful for optimum designs and safety analysis of molten salt cooled pebble bed reactors.

Pressure Drop in a Pebble Bed Reactor Under High Reynolds Number

2012 ◽  
Vol 180 (2) ◽  
pp. 159-173 ◽  
Author(s):  
Yassin A. Hassan ◽  
Changwoo Kang
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
High Reynolds Number ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
High Reynolds

Fuel elements of the high temperature pebble bed reactor

1975 ◽  
Vol 34 (1) ◽  
pp. 93-108 ◽  
Author(s):  
L. Wolf ◽  
G. Ballensiefen ◽  
W. Fröhling
Keyword(s):  
High Temperature ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
Fuel Elements

scholarly journals Computational Model for the Neutronic Simulation of Pebble Bed Reactor’s Core Using MCNPX

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
J. Rosales ◽  
A. Muñoz ◽  
C. García ◽  
L. García ◽  
C. Brayner ◽  
...  
Keyword(s):  
High Temperature ◽  
Computational Model ◽  
Inherent Safety ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
Triso Fuel ◽  
Very High Temperature Reactor ◽  
Fuel Design ◽  
High Temperature Reactor ◽  
Very High

Very high temperature reactor (VHTR) designs offer promising performance characteristics; they can provide sustainable energy, improved proliferation resistance, inherent safety, and high temperature heat supply. These designs also promise operation to high burnup and large margins to fuel failure with excellent fission product retention via the TRISO fuel design. The pebble bed reactor (PBR) is a design of gas cooled high temperature reactor, candidate for Generation IV of Nuclear Energy Systems. This paper describes the features of a detailed geometric computational model for PBR whole core analysis using the MCNPX code. The validation of the model was carried out using the HTR-10 benchmark. Results were compared with experimental data and calculations of other authors. In addition, sensitivity analysis of several parameters that could have influenced the results and the accuracy of model was made.

Optimization of a Radially Cooled Pebble Bed Reactor

2008 ◽  
Author(s):  
B. Boer ◽  
J. L. Kloosterman ◽  
D. Lathouwers ◽  
T. H. J. J. van der Hagen ◽  
H. van Dam
Keyword(s):  
Pressure Drop ◽  
Temperature Profile ◽  
Flow Direction ◽  
Outer Region ◽  
Fissile Material ◽  
Fuel Temperature ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
The Core ◽  
Power Profile

By altering the coolant flow direction in a pebble bed reactor from axial to radial, the pressure drop can be reduced tremendously. In this case the coolant flows from the outer reflector through the pebble bed and finally to flow paths in the inner reflector. As a consequence, the fuel temperatures are elevated due to the reduced heat transfer of the coolant. However, the power profile and pebble size in a radially cooled pebble bed reactor can be optimized to achieve lower fuel temperatures than current axially cooled designs, while the low pressure drop can be maintained. The radial power profile in the core can be altered by adopting multi-pass fuel management using several radial fuel zones in the core. The optimal power profile yielding a flat temperature profile is derived analytically and is approximated by radial fuel zoning. In this case, the pebbles pass through the outer region of the core first and each consecutive pass is located in a fuel zone closer to the inner reflector. Thereby, the resulting radial distribution of the fissile material in the core is influenced and the temperature profile is close to optimal. The fuel temperature in the pebbles can be further reduced by reducing the standard pebble diameter from 6 cm to a value as low as 1 cm. An analytical investigation is used to demonstrate the effects on the fuel temperature and pressure drop for both radial and axial cooling. Finally, two-dimensional numerical calculations were performed, using codes for neutronics, thermal-hydraulics and fuel depletion analysis, in order to validate the results for the optimized design that were obtained from the analytical investigations. It was found that for a radially cooled design with an optimized power profile and reduced pebble diameter (below 3.5 cm) both a reduction in the pressure drop (Δp = −2.6 bar), which increases the reactor efficiency with several percent, and a reduction in the maximum fuel temperature (ΔT = −50 °C) can be achieved compared to present axially cooled designs.

Numerical Simulation of Accident Scenario in HTGR (Pebble Bed Reactor) Using COMSOL® Code

2013 ◽  
Author(s):  
Geoffrey J. Peter
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Computer Code ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
Accident Scenario ◽  
Flow And Heat Transfer ◽  
Custom Made ◽  
Accident Scenarios ◽  
High Temperature Gas

High Temperature Gas Cooled Reactor (HTGR) development and operation is expanding in the United Kingdom, Russia, USA (Generation IV Reactors), and France (Pebble Bed Modular Reactor, PBMR). A prototype pebble bed reactor producing 10 MW thermal, High Temperature Reactor (HTR-10) is in operation in China. However, the general public remains skeptical of the safety and the perceived dangers of possible accidents. Of particular concern are blockages caused by local variations in flow and heat transfer that lead to hot spots within the bed. This paper models the accident scenario resulting from blockages due to the retention of dust in the coolant gas or from the rupture of one or more fuel particles used in the High Temperature Gas Cooled (Pebble Bed) Nuclear Reactors using the commercially available computer code COMSOL. Numerical modeling of flow and heat transfer in a packed bed produces an Elliptical Non-Linear Partial Differential equation that requires custom made computer codes. Previously published results obtained from the use of a custom-made verified computer code are limited to one accident scenario and involve considerable modification to study different accident scenarios. Thus the use of a commercially available computer code that can simulate many different accident scenarios is of considerable advantage. Further, this paper compares numerical solutions obtained from custom-made computer code with COMSOL simulation and discusses the advantages and limitations of both codes.

scholarly journals KARAKTERISASI RADIONUKLIDA PADA BAHAN BAKAR BEKAS DARI EXPERIMENTAL PEBBLE BED REACTOR

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
Aisyah Aisyah ◽  
Mirawaty Mirawaty ◽  
Dwi Luhur Ibnu Saputra ◽  
Risdiyana Setiawan
Keyword(s):  
High Temperature ◽  
Pebble Bed ◽  
Pebble Bed Reactor ◽  
High Temperature Gas

KARAKTERISASI RADIONUKLIDA PADA BAHAN BAKAR NUKLIR BEKAS DARI EXPERIMENTAL PEBBLE BED REACTOR. Arbeitsgemeinschaft Versuchsreaktor (AVR) merupakan reaktor nuklir jenis High Temperature Gas Cooled Reactor (HTGR) yang menggunakan bahan bakar berbentuk pebble berlapis TRISO dengan tipe yang sama  dengan Reaktor Daya Eksperimental (RDE) yang direncanakan akan dibangun di Indonesia. Oleh karena itu karakteristik radionuklida dalam bahan bakar bekas (BBNB) reaktor AVR dapat digunakan untuk mempelajari karakteristik BBNB reaktor RDE. Salah satu hal penting dalam operasional reaktor nuklir adalah pengelolaan BBNB yang ditimbulkannya. Pengelolaan BBNB reaktor AVR dilakukan dengan penyimpanan dalam dry cask untuk jangka waktu yang lama. Upaya untuk mendisain keselamatan dalam sistem penyimpanan BBNB salah satu kajian penting yang diperlukan adalah karakterisasi radionuklida yang terkandung dalam BBNB. Pada penelitian ini dilakukan karakterisasi radionuklida yang terkandung dalam BBNB dengan menggunakan software ORIGEN 2.1 yang didasarkan pada operasional reaktor AVR. Penelitian ini bertujuan untuk analisis keselamatan penyimpanan BBNB pebble pada dry cask dalam jangka panjang. Hasil penelitian menunjukkan bahwa sampai dengan waktu penyimpanan selama 100 tahun, BBNB sebuah pebble memiliki karakteristik radionuklida hasil aktivasi, aktinida dan anak luruhnya, serta radionuklida hasil fisi dengan total konsentrasi aktivitas sebesar 4,03x1010 Bq/g. Sampai dengan waktu penyimpanan 100 tahun konsentrasi aktivitas radionuklida total dalam dry cask sebesar 7,66x1013 Bq/g untuk kapasitas dry cask yang berisi BBNB pebble berjumlah 1900 buah. Terdapat BBNB pebble dalam dry cask yang mengalami kerusakan pada lapisan TRISO, sehingga dalam  dry cask kemungkinan terdapat beberapa radionuklida hasil fisi yang dapat lepas dari BBNB  seperti 85Kr, 135Xe, dan 131I yang berupa gas, serta  137Cs,106Ru, 110mAg dan 107Pd yang bersifat logam.Kata kunci: Karakterisasi radionuklida, AVR, bahan bakar nuklir bekas, pebble berlapis TRISO

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