Comparative analysis of preliminary design core of TRIGA Bandung using fuel element plate MTR in Indonesia

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1 Comparative analysis of preliminary design core of TRIGA Bandung using fuel element plate MTR in Indonesia Anwar Ilmar Ramadhan, Efrizon Umar, Nathanael Panagung Tandian, and Aryadi Suwono Citation: AIP Conference Proceedings 1799, (2017); View online: View Table of Contents: Published by the American Institute of Physics Articles you may be interested in Automated power control system for reactor TRIGA PUSPATI AIP Conference Proceedings 1799, (2017); / Investigation on alternative methods to enhance the cooling capacity of an open pool reactor AIP Conference Proceedings 1799, (2017); / Thorium fueled reactor AIP Conference Proceedings 1799, (2017); / Detection of underground water distribution piping system and leakages using ground penetrating radar (GPR) AIP Conference Proceedings 1799, (2017); / National data centre preparedness exercise 2015 (NPE2015): MY-NDC progress result and experience AIP Conference Proceedings 1799, (2017); / Neutronics calculation of RTP core AIP Conference Proceedings 1799, (2017); /

2 Comparative Analysis of Preliminary Design Core of TRIGA Bandung Using Fuel Element Plate MTR in Indonesia Anwar Ilmar Ramadhan 1,3,a), Efrizon Umar 2, Nathanael Panagung Tandian 1, Aryadi Suwono 1 1 Thermodynamics Laboratory, Faculty of Mechanical and Aerospace Engineering, Institut Teknologi Bandung Jl. Ganesha No 10 Bandung 40132, Indonesia 2 Center for Applied Nuclear Science and Technology, National Nuclear Energy Agency of Indonesia [BATAN] Jl. Tamansari No 71 Bandung 40132, Indonesia 3 Department of Mechanical Engineering, Faculty of Engineering, Universitas Muhammadiyah Jakarta Jl. Cempaka Putih Tengah 27 Jakarta 10510, Indonesia a) Corresponding author: airamadhan@students.itb.ac.id Abstract. TRIGA Bandung is a research nuclear reactor owned by Indonesia, located in Bandung with a power of 2 MWth. Nuclear research reactor TRIGA Bandung is used as a center for applied research and development in the field of application of the nuclear technologies. TRIGA Bandung is currently still using a cylindrical fuel element, this raises a new problem - the limited number of existing fuel element. The purpose of this research is the development of the preliminary core design of a nuclear research reactor TRIGA Bandung using fuel element plate MTR. The research method is modeling and simulation the preliminary design core of nuclear research reactor TRIGA Bandung using comparative method of porous media and non-porous media with CFD code. This research shows the velocity flow and temperature distribution and the influence of pressure from the comparison method of k-ε standard model and porous media model at the preliminary design in the core area of TRIGA Bandung research reactor with fuel element plate MTR. INTRODUCTION The nuclear reactor has two types based on the function that is used for electrical energy generation and research reactor that produces radioisotopes and for nuclear science and technology research. Indonesia has three research reactors, namely two types of TRIGA research reactor in Bandung with a power of 2 MW and in Yogyakarta with a power of 100 kw and a research reactor in PUSPIPTEK Serpong with nominal power of 30 MW [1]. Fuel elements used by both types of TRIGA reactors currently are made of cylindrical material element [2-5], while the fuel elements RSG-GAS reactor in Serpong uses fuel element of plate type [6][7]. These three nuclear research reactors, owned by Indonesia, are used for research, radioisotopes production and training related to nuclear science and technology. TRIGA Bandung reactor is a reactor that can be used to predict a buffer in development of research reactor and radioisotope production on scale of national and international. This reactor has a problem due to the limited number of existing fuel elements as the cylinder fuel elements are no longer manufactured by General Atomics. The necessary steps to modify the design of the TRIGA reactor core using the fuel element plate MTR (Material Testing Reactor) that can be made by PT. Inuki in Indonesia [8]. Research on modification of the TRIGA research reactor core by replacing the nuclear fuel elements with fuel element of plate cylinder type has never been done before. Heat and mass transfer methods that can be analyzed further using several methods, one of the approaches used in the fuel element plate is a method of porous media [9-12]. In this research, modeling and simulation of the preliminary design of a nuclear reactor with the TRIGA research reactor core configurations using fuel element plate MTR is carried out, by comparing the model of porous media and k-ε standard model [Figure 1]. Advancing Nuclear Science and Engineering for Sustainable Nuclear Energy Knowledge AIP Conf. Proc. 1799, ; doi: / Published by AIP Publishing /$

3 Existing Fuel Cylinder Fuel Conversion Fuel Element Next Fuel Fuel Element Plate MTR FIGURE 1. Modification Research of TRIGA Bandung Reactor With Fuel Element Plate MTR. Core components and the research nuclear reactor facility powerless 2 MWh and TRIGA reactor core configuration can be seen in Figure 2 and 2 below: FIGURE 2. Facilities owned the TRIGA nuclear research reactor [13]; Nuclear reactor core configurations of TRIGA nuclear research reactor [14]. Figure 2 shows the facility or the reactor components that are contained in a research nuclear reactor of power 2 MWth, such as: beam tube, reflector, thermal column, fuel elements, reactor tank, rotary specimen rack, etc. Figure 2 shows the TRIGA reactor core configurations with cylindrical fuel element, that has slab grid located on the upper core reactor with a radius of 26.5 cm consisting of fuel elements, moderator and graphite elements (dummy). Third nuclear reactor core volume is occupied by water. This nuclear reactor uses a reflector made from graphite with thickness of 28.4 cm. The whole arrangement is enclosed in an aluminum bonded to the tank bottom. The nuclear research reactor of TRIGA 2 MWth has five control rods were made of absorbent material Boron Carbide (B4C), with its underneath followed by fuel rods. Its irradiation facilities consist of four pipes that penetrate the file from the core through water and concrete to outer surface of shield structure. Shelves footage in the hole above the reflector ring is used as a place of irradiation to produce radioisotopes. Fuel element plate MTR accompanied with the dimensions as shown in Figure

4 FIGURE 3. Fuel Elements plate MTR in nuclear reactor research RSG GAS [15] Figure 3 shows the fuel element plet MTR used in RSG GAS Serpong. The fuel element plate has a length dimension [mm]; wide of [mm] ; high of [mm]. A fuel element assembly consists of 21 grid plates, each of which contains U 3 Si 2 -Al enrichment of 19.75% U 235. RESEARCH METHOD Preliminary Design Modeling TRIGA Reactor The preliminary design of the core reactor of TRIGA Bandung fuel element plate MTR was carried out using modeling with regard to reactor core components that existed previously in the reactor core. Considerations taken when making models of the preliminary design are: the use of chimney, reactor core configurations used by the fuel element plate numbered 20 plates [15]. Modeling of the preliminary design of TRIGA reactor is shown in Figure 4. FIGURE 4. Modeling Preliminary Design Reactor using CAD Code

5 Boundary Condition Determination of the boundary conditions of the boundary consists of input, output and energy at the fuel element plate MTR. Input type is defined by the inlet velocity, then the output is defined by the outlet pressure, the energy input to the MTR fuel element plate is value of heat flux is uniform and constant. Simulations by using CFD Code of modeling that have been defined in the CAD Code (Table 1 and Figure 5). TABLE 1. Parameters boundary conditions Boundary Type Value Velocity Inlet [16] [m/s] 3.29 Fluid inlet temperature [16] [ o C] 32.2 Heat Flux [15] [W/m 2 ] Inlet Chimney Fuel Element Plate Outlet FIGURE 5. The boundary condition of the preliminary design of the TRIGA reactor. k-ε Standard Model k-ε standard model of a semi-empirical models based on transport equation model for turbulent kinetic energy (k) and the rate of dissipation (ε), which was developed by Launder and Spalding. Turbulent kinetic energy (k) and the rate of dissipation (ε), obtained from the following transport equation: and, t t x t k kui Gk Gb p YM S k i x j k k x j (1) x x k x j t ui C1 Gk G3 Gb ) C2 p S i j 2 k ( (2) G k in the equation formation of turbulent kinetic energy with a mean velocity gradient. G b is the formation of turbulent kinetic energy due to buoyancy forces. Y m stated contribution dilatation fluctuations in the turbulent flow of incompressible not on the rate of dissipation as a whole. While the value of C 1ε, C 2ε, and C 3ε are constants, σ k and σ ε are turbulent Prandtl number (Pr) for k and ε respectively. S k and S ε are defined as tribal sources. Constants values are C 1ε = 1.44, C 2ε = 1.92, C 3ε = 0.09, σ k and σ ε = 1.0 = 1.3. k-ε standard model used for Reynolds number (Re) is high

6 Porous Media Model Porous media in CFD Code is modeled using additional source terms in the momentum equation given by Equation (3): S i 3 3 j Dij j j1c ij 1 2 mag j 1 (3) where, S i is the source term for the i (x, y or z) momentum equation, v j is the velocity component in j (x, y or z) direction, v mag is the velocity magnitude, and μ is the fluid viscosity. The first term on the right hand side of Equation 3 is the viscous pressure loss term (Darcy term) due to the porous media structure. The second term (Forchheimer term) represents the pressure loss due to the momentum of the flow in the porous media zone. The parameter tensor D ij, called viscous resistance factor, and C ij, called inertial resistance factor, are defined by the users. This simplification may lead to lower turbulent kinetic energy and turbulent viscosity, since turbulent kinetic energy equation of standard k-ε model does not include the term corresponding to porous media induced turbulence [17]. RESULTS AND DISCUSSION Analysis of Temperature Distribution The results of numerical simulations the preliminary design core reactor TRIGA Bandung using CFD Code obtained distribution of temperature, velocity flow distribution and pressure distribution on core reactor of TRIGA Bandung with fuel element plate MTR. The distribution of temperature in the area of chimney, porch in the reactor fuel element plate and output areas in the preliminary design of the core of nuclear research reactor TRIGA Bandung can be seen in Figure 6. FIGURE 6. Distribution of Temperature at Preliminary of Design Core Reactor of TRIGA: k-ε standard Model; Porous Media Model. Figure 6 shows the results of numerical simulation conditions for the distribution of temperature in the preliminary design of core reactor TRIGA Bandung using standard k-ε model and Porous Media Model. Figure 6 for k-ε standard model shows a change in temperature from the preliminary temperature of the input of 32.2 [ C] at Chimney as the inlet, increase the temperature to 33.1 [ C] after passing the fuel element plate given heat flux at [W/m 2 ]. Figure 6 for state Porous Media Model, has a similar pattern, namely the distribution of temperature in the chimney at 32.2 [ C] and increase the output area after going through fuel element plate MTR of 33.2 [ o C], but the temperature distribution patterns output area more even than the standard k-ε models. The temperature distribution pattern that occurs on fuel element plate MTR in the preliminary design of the TRIGA reactor core can be seen in Figure 7 and Figure

7 FIGURE 7. Curve plot of distribution of Temperature in Fuel Element Plate MTR at Preliminary of Design Core Reactor of TRIGA with: a. k-ε standard Model; b. Porous Media Model Figure 7 shows the pattern of temperature distribution that occurs in the fuel element plate MTR in the early design of core reactor TRIGA by the method of k-ε standard model, it appears clearly that the distribution of temperature on fuel elements show very big increase with the smallest at 32.8 [ C] and most of it is 35.3 [ o C]. The curve indicates the temperature large deployment integrating fuel element plate MTR. This happens because the k-ε standard model has fairly high value fluctuations in the grid plate fuel element. Figure 7 shows the distribution pattern of temperature on fuel element plate MTR in the preliminary design of the core nuclear reactor research TRIGA with Porous Media models. It appears that this model has a distribution temperature is more uniform and shorter than the k-ε standard model, the porous media model are temperatures of at least small is 32.9 [ C] and most earned 35.0 [ o C]. Influence of Darcy term in fuel element which has a lower plate turbulent kinetic energy and turbulent viscosity. Analysis of Velocity Distribution Comparative analysis was carried out to determine the subsequent flow velocity distribution pattern that occurred reactor core area, especially in the chimney, fuel element plate and output area of the preliminary design of the TRIGA reactor core (Figure 8). FIGURE 8. Distribution of Velocity flow at Preliminary of Design Core Reactor of TRIGA: k-ε standard Model; Porous Media Model. Figure 8 shows the flow rate of phenomena that occurs in the preliminary design of the TRIGA reactor core. Figure 8 shows the result of CFD Code numerical simulation method with k-ε standard model, the visible blue is a low flow speed at a speed of 3.69 [m/s] in chimney area. When it enters the core area which contains the reactor fuel element plate, an increase in the flow rate of 4.89 [m/s], after passing through the fuel element plate MTR with accelerated flow velocity of 23.2 [m/s]. Porous Media Model which occurred in the preliminary design of the core TRIGA reactor, as in Figure 8 with velocity flow area chimney at 3.28 [m/s], area before entering the core area is 6.76 [m/s], area output after the fuel element plate by 25.7 [m/s]. Subsequent analysis focused on the area of

8 chimney [see Figure 9], local fuel element plate MTR [see Figure 10] and the output area after the fluid passing through the fuel elements plate MTR [see Figure 11]. From each of these areas can be studied more in depth about the phenomenon of the spread and flow rate that occurred in the preliminary design of the core TRIGA research nuclear reactor using fuel element plate MTR. FIGURE 9. Distribution of Velocity flow at Preliminary of Design Core Reactor of TRIGA on Chimney area: k-ε standard Model; Porous Media Model. Figure 9 describes the distribution pattern of the flow velocity in the chimney, before the cooling fluid entering the core area that contains the reactor fuel element plate MTR. The second figure above shows that the flow rate was greater in the k-ε standard models compared to porous media model. Particularly noticeable flow occurred in the area of handle of fuel element plate in Figure 9. While Figure 9 shows that for a smaller model of porous media, flow velocities occurs at handle of fuel element plate area. FIGURE 10. Distribution of Velocity flow at Preliminary of Design Core Reactor of TRIGA on after Fuel Element Plate area: a. k-ε standard Model; b. Porous Media Model Figure 10 shows the phenomenon of the flow rate that occurred after passing the fuel element plate with k-ε standard model, where an increase in flow velocity along the length MTR fuel element plate. This is due to the heating by conduction and convection of the fuel element plate of the fluid, so that the fluid is getting hot, and the flow velocity increases its ride. Likewise in Figure 10, it can be seen that an increase in flow rate after passing through the fuel element plate. Only for Porous media model, more uniform flow velocity that occurs instead of the k-ε standard. Flow rate in Figure 10 has a velocity magnitude of 14.9 [m/s] and k-ε standard model (Figure 10 ) is 13.5 [m/s]. Figure 10 shows the numeric results are the same, namely an increase in the flow at end fitting of fuel element plate MTR, this happens due to the narrowing of the flow of fluid passing through the fuel element plate MTR. Figure 11 shows the distribution pattern of fluid flow velocity that occurs the output area after passing the fuel element plate MTR. Figure 11 explains the phenomenon of fluid flow with k-ε standard model, after passing through the fuel element plate area, the flow velocity of 13.5 [m/s] will increase the output area core reactor of

9 TRIGA Bandung to 23.2 [m/s]. Visible also is the spreading pattern that does not look too uneven flow area output after the fuel element plate, compared to porous media models. Figure 11 shows that the fluid flow phenomena which occurs almost with equal increase of k-ε standard model, of 14.9 [m/s] to 25.7 [m/s] in output core area. Porous media flow model shows a pattern of spread better and more even after passing the fuel element plate MTR. FIGURE 11. Distribution of Velocity at Preliminary of Design Core Reactor of TRIGA on Outlet area: k-ε standard Model; Porous Media Model. Analysis of Pressure Distribution Subsequent analysis is the distribution pattern of pressure that occurs in the preliminary design of the core nuclear research reactor of TRIGA Bandung using fuel element plate MTR, can be seen in Figure 12 for the design of the reactor core and Figure 13 for MTR fuel element plate in the preliminary design of the TRIGA reactor core. FIGURE 12. Distribution of Pressure at Preliminary of Design Core Reactor of TRIGA: k-ε standard Model; Porous Media Model Figure 12 shows the spread of the pressure reactor core area of the preliminary design of a nuclear reactor research TRIGA Bandung. Figure 12 shows the pressure distribution with k-ε standard model: the pressure that occurs in chimney area is very large compared to the exit after passing the fuel element plate, each pressure value is , then the pressure decreased output area of , As for the model of porous media pressure drops of become , this happens because there are viscous resistance factor and inertial resistance factor in porous media model

10 FIGURE 13. The pressure distribution curve on fuel elements MTR plate with: k-ε standard model; porous media model. Figure 13 describes the distribution pattern of pressure that occurs in fuel element plate MTR in the preliminary design of a core nuclear reactor research of TRIGA Bandung. Figure 13 shows the pressure drop that occurs at the fuel element plate MTR of the simulation results using the k-ε standard model, the preliminary pressure of then decreased pressure becomes Figure 14 shows that the porous media model has a similar pattern with k-ε standard models, namely the existing preliminary pressure by fuel element plate MTR in to This proves the research that has been done Y.Yan, et. al. [17], see Figure 14. FIGURE 14. Numerical Simulation Results Pressure drop [17]. CONCLUSION The conclusions for this research are: Temperature distribution that occurred in the preliminary design of the core research nuclear reactor of TRIGA Bandung, using k-ε standard model and Porous Media model showed similar pattern, i.e. an increase in temperature. Porous Media model has the advantage of a more equitable distribution of temperature rise in the area surrounding the core design output than k-ε standard model. The distribution of the flow rate that occurred in the preliminary design of the TRIGA research nuclear reactor core showed a similar pattern, in both models, i.e. an increase in the flow rate that from the chimney to the output area core. The pressure distribution on both models showed a decrease of pressure in the preliminary design of the TRIGA research nuclear reactor core

11 ACKNOWLEDGEMENTS This research was supported by National Nuclear Energy Agency of Indonesia (BATAN) and Ministry of Research, Technology, and High Education Republic of Indonesia with Contract/Grant Number: 55.1/LPPM- UMJ/VIII/2016. REFERENCES 1. L. Suparlina, Proceeding of Meeting and Scientific Presentations-Basic Research Science and Nuclear Technology 2011 (2011). 2. E. Umar and R. Fiantini, The 2nd International Conference on Advances in Nuclear Science and Engineering 2009ICANSE 2009) (AIP Conference Proceedings) Vol. 1244, (2010). 3. R. Fiantini and E.Umar, The 2nd International Conference on Advances in Nuclear Science and Engineering 2009ICANSE 2009) (AIP Conference Proceedings) Vol. 1244, (2010). 4. E. Umar, Atom Indonesia, 27 (1),67-84 (2001). 5. E. Umar, K. Kamajaya, A. Suwono, N. P. Tandian and T. Hardianto, Proceedings of the International Conference on Fluid and Thermal Energy Conversion 2003, Indonesia (2003). 6. G. A. Mandala, 6 th National Seminar of Human Resources for Nuclear Technology (2010). 7. M. Subekti, D. Isnaini, E. P. Hastuti, Journal of Nuclear Reactor Technology, Vol. 15 No 2, pp (2013). 8. H. Raflis, Proceeding of the 17 th National Seminar of NPP Safety Technology and Nuclear Facilities (2011). 9. S. U. D. Khan et. al., Annals of Nuclear Energy 53, (2013). 10. A. Mesquita, et. al., International Nuclear Atlantic Conference (2011) 11. S. Safi, S. Benissaad, Adv. Theor. Appl. Mech., Vol 5 No 1, pp (2012). 12. M. M. Lianes, et al, International Nuclear Atlantic Conference (2011). 13. K. Kamajaya, et. al., The Current Status of Bandung TRIGA Mark-II Reactor Indonesia, Bandung (2006). 14. National Nuclear Energy Agency, Safety Analysis Report TRIGA 2000 Bandung Reactor, National Nuclear Energy Agency (2006). 15. P. Basuki, et. al., Journal of Nuclear Science and Technology Indonesia, Vol. 15 No 2, pp (2014). 16. R. Nazar, Journal of Nuclear Reactor Technology, Vol. 13 No 3, pp (2011). 17. Y. Yan, Rizwan-uddin, N. Sobh, Proceeding of Mathematics and Computation, Supercomputing, Reactor Physics and Nuclear and Biological Applications (2005)