atw - International Journal for Nuclear Power | 2.2024

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68 Research and Innovation replaced with the FCM fuel based on the UN and UCO kernel of Triso fuels without the alternation of core constraints and design. The performance of the can didate fuel (UN and UCO) has been compared with the reference core under identical design constraints. Fig. 2a. FCM fuel rod (right) and Conventional LWR Fuel Rod (left) [9] 2. SMART Reactor core and FCM fuel replacement. SMART is an advanced and multipurpose SMR with 330 MWt power and can produce 40,000 m³/day through desalination [15] . The SMART reactor core is composed of 57 fuel assemblies of a 17 ×17 fuel assembly array. Each assembly contains 264 fuel rods, 24 control rods guided tubes and central instrumentation guided tube control. Low-enriched uranium oxide is used as the fuel, which provides sufficient reactivity for three years of refueling length of continuous operation. The design of code of divided into two zones depending upon the enrichment. The zone one and zone assemblies contain fuel enrichment of 2.82 % and 4.88 % respectively [16] . Integral burnable absorber rods in the form of Gd2O3 are used to reduce the excess reactivity and flatten core power distribution [17] . The original design of the SMART reactor code is depicted in Figure 3 and the fuel assembly configuration is presented in Table 1. Fig. 2b. Cross-section view of conventional oxide fuel rod (right) and the SMART Reactor FCM fuel (left) concept. layers. These practices are then embedded randomly in a SiC matrix identical to the conventional fuel pellet [11] . The function of a low-carbon buffer is to slow down and retention of fission products. The function of pyrolytic carbon is severalfold, including the protection of kernel from aggressive process gases used in Trio’s processing, from energetic fission product re coil da mage, and providing thermal and mechanical stability [3, 7, 12] . The conventional fuel UO₂ of LWR had shown a feeble tolerance to issues like swelling degradation, cracking, and expansion under high-temperature scenarios [12] . After the recent event of the Fukushima Daiichi Nuclear power plant accident in Japan, interest has been developed to enhance the ATF for LWRs [13] . In this regard, Oak Ridge National Laboratory (ORNL) has developed TRISO-based FCM fuel which is based on proven HTGR technology. FCM fuel has been proposed for the LWRs and it could be adopted for the SMRs. The main concerning issues in employing FCM fuel in LWRs are the fuel cycle length and neutronic performance. In this work, we focused on the feasibility of the replacement of UO₂ fuel with the UN and UCO FCM fuel for SMART reactors. The OpenMC [14] has been used for the computation analysis of the SMART reactor core. The reference core of the SMART reactor has been Fig. 3. SMART reactor core Cross-section view (Left), [7, 19] and assembly Configuration (Right). 2.1 FCM Fuel replacement In this study SMART reactor core with its original geometry is replaced with the FCM fuel material of UN and UCO kernel (See Table 2). Baumann et al. [20] have suggested the UN TRISO fuel concept for the higher burnup LWRs application with 19.5 % enrichment. UN kernel of 800mm was ideal. Power J.J [21] has suggested the UCO for LWRs [22] and has used the UCO-TRISO fuel of 500 mm kernel for LWRs with 19.75 % enrichment. Therefore, in this study, UCO and UN-based Triso base FCM fuel of 800 kernels 870 µm and 850 µm respectively with heterogeneous enrichment have been employed in the SMART reactor core. The SMART reactor core has been configured with two zones with enrichment of enrichment 4.88 wt % 235 U and 2.82 wt % 235 U. Therefore, the same argument has been taken into consideration for FCM enrichment. In FCM fuel design part of the fuel pallet is occupied by the SiC matrix Ausgabe 2 › März
Research and Innovation 69 therefore higher enrichment is needed to achieve the same amount of fissile material. Therefore, 15.5 % and 9.5 %, enrichment is selected for Zone 2 and Zone 1 respectively. The packing fraction determined the number of Triso fuel particles per fuel rod. Since, as the packing fraction increases the pitch rapidly decreases. The simulated dismissions of FCM fuel pellets and conventional fuel pellets are depicted in Tab. 2. The kernel-to-particle volume ratio and the particle packing fraction combination for simulated TRISO cases resulted in 75 – 80 % of 235 U fissile density compared to standard uranium dioxide fuel pellets. Type Assembly type No. of Assemblies No. of fuel rods Enrichment 235 U w/o% No. of IFBA rods Gd 2 O 3 (w/o%) A 8 260 4.88 4 8.0 Zone 2 Zone 1 B 12 244 4.88 20 8.0 BZ 12 256 4.88 8 8.0 BC 4 240 4.88 24 8.0 C 9 256 2.82 8 8.0 CZ 12 252 2.82 12 8.0 Tab. 1. Fuel assembly configuration of SMART reactor [18] . Pentameter Conventional UO 2 pellet FCM Fuel pellet UCO-Case UN-case TRISO Particle Kernel Material type - UCO (5% porosity) UN (5% porosity) Coating material - IPyC, SiC, OPyC IPyC, SiC, OPyC Kernel diameter (µm) - 870 850 Buffer thickness (µm) - 55 70 Density of Buffer - 0.79 0.79 Layers thickness IPyC, SiC, OPyC (µm) - 35, 35, 35 35, 35, 35 Densities of IPyC, SiC, OPyC (µm) - 1.9, 4.21, 1.9 1.9, 4.21, 1.9 Density of Kernel - 13.76 13.76 Fuel radius (mm) - 3.922 3.922 Rod diameter (mm) - 9.5 9.5 Packing fraction - 0.60 0.48 TRISO Pitch (mm) - 1.13 1.23 Number of TRISO per Rod - 64090 51270 U 235 (%) a - 9.5, 15.5 9.5, 15.5 The average density of Tirso particle g.cm -3 - 10.87 13.68 Density of fuel (g.cm -3 ) 10.28 - - Fuel rod Active Fuel rod Length cm 200 200 200 Fuel diameter 8.19 8.19 8.19 Pin pitch (mm) 0.12598 0.12598 0.12598 Helium gap (mm) 0.028 0.028 0.028 Cladding outer diameter mm 9.5 9.5 9.5 Cladding inner diameter (mm) 9.5 8.22 8.22 Fuel Assembly Assembly pitch (cm) 21.504 21.504 21.504 Assembly matrix 17×17 17×17 17×17 Tab. 2. FCM fuel pellet UN and UCO base FCM fuel and fuel rod specifications a Zone 2 and Zone 1 Vol. 69 (2024)
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ISSN: 1431-5254 (Print) | eISSN: 29
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4 Contents Inhalt Editorial Abschie
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6 Calendar Kalender 2024 07.03.2024
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8 Feature: Energy Policy, Economy
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Page 18 and 19: 18 Energy Policy, Economy and Law
Page 30 and 31: 30 Operation and New Build Meta Qu
Page 32 and 33: 32 Operation and New Build Fig. 2.
Page 34 and 35: 34 Operation and New Build It woul
Page 36 and 37: 36 Operation and New Build VR Topi
Page 38 and 39: 38 Operation and New Build Fig. 8.
Page 40 and 41: 40 Operation and New Build [47] Bo
Page 42 and 43: 42 Operation and New Build [127] H
Page 44 and 45: 44 Environment and Safety Initial
Page 46 and 47: 46 Environment and Safety S/N Docu
Page 48 and 49: 48 Environment and Safety compared
Page 50 and 51: 50 Environment and Safety EPZ EPD
Page 52 and 53: 52 Environment and Safety Emergenc
Page 54 and 55: 54 Environment and Safety In 2015,
Page 56 and 57: 56 Environment and Safety populati
Page 58 and 59: 58 Environment and Safety [38] A.
Page 60 and 61: 60 Environment and Safety Evaluati
Page 62 and 63: 62 Environment and Safety Material
Page 64 and 65: 64 Environment and Safety EFPY (Ef
Page 66 and 67: 66 Environment and Safety Referenc
Page 70 and 71: 70 Research and Innovation 2.2 Mod
Page 72 and 73: 72 Research and Innovation fuel (U
Page 74 and 75: 74 Research and Innovation [12] Po
Page 76 and 77: 76 Spotlight on Nuclear Law auf Ko
Page 78 and 79: 78 KTG-Fachinfo KTG-Fachinfo 02/202
Page 80 and 81: 80 KTG-Fachinfo Regierungsbericht v
Page 82 and 83: 82 Vor 66 Jahren Ausgabe 2 › Mä
Page 88 and 89: 88 Kerntechnik 2024 Technical Sess
Page 90 and 91: 90 Kerntechnik 2024 Technical Sess
Page 92 and 93: 92 Kerntechnik 2024 Partner, Ausst
Page 94 and 95: 94 KTG Inside Die KTG gratuliert a
Page 96 and 97: 96 KTG Inside † Nachruf Die Kern
Page 98 and 99: 98 KTG Inside † Nachruf Die Kern
Page 100 and 101: 100 KTG Inside † Nachruf Die Ker
Page 102 and 103: 102 Report ⁃ Seitens der Internat
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