The Experts below are selected from a list of 1980 Experts worldwide ranked by ideXlab platform
Mamoru Ishii - One of the best experts on this subject based on the ideXlab platform.
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experimental study of blowdown event in a pwr type Small Modular Reactor
Nuclear Technology, 2019Co-Authors: Guanyi Wang, Shanbin Shi, Yikuan Yan, Zhuoran Dang, Xiaohong Yang, Mamoru IshiiAbstract:AbstractAs one of the future directions of nuclear energy development, Small Modular Reactor (SMR) designs meet the demands of safety, sustainability, and efficiency by eliminating circulating pump...
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experimental study on accident transients and flow instabilities in a pwr type Small Modular Reactor
Progress in Nuclear Energy, 2017Co-Authors: Guanyi Wang, Shanbin Shi, Yikuan Yan, Xiaohong Yang, Mamoru IshiiAbstract:Abstract Experimental study on natural circulation flow instabilities is of great importance for the safety analysis in a PWR-type SMR, especially for accident scenarios such as loss of coolant accident (LOCA) and loss of heat sink accident (LOHS). In this study, an experimental natural circulation facility was built by scaling down from a typical PWR-type SMR. The scaling ratios were derived from non-dimensional field and constitutive equations of the drift flux model. The test facility has a height of 3.44 m with an operating pressure limit of 1.0 MPa. Two kinds of tests, the blowdown test and cold-blowdown test were performed. The blowdown test was designed to simulate the low pressure phase (
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a core design study for a Small Modular boiling water Reactor with long life core
Nuclear Technology, 2016Co-Authors: W S Yang, Shanbin Shi, Mamoru IshiiAbstract:This paper presents the core design and performance characteristics of the Novel Modular Reactor (NMR-50), a 50-MW(electric) Small Modular Reactor. NMR-50 is a boiling water Reactor with na...
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a core design study for a Small Modular boiling water Reactor with long life core
Nuclear Technology, 2016Co-Authors: W S Yang, Shanbin Shi, Mamoru IshiiAbstract:AbstractThis paper presents the core design and performance characteristics of the Novel Modular Reactor (NMR-50), a 50-MW(electric) Small Modular Reactor. NMR-50 is a boiling water Reactor with natural-circulation cooling and two layers of passive safety systems that enable the Reactor to withstand prolonged station blackout and loss of ultimate heat sink accidents. The main goal in the core design is to achieve a long-life core (~10 years) without refueling for deployment in remote sites. Through assembly design studies with the CASMO-4 lattice code and coupled neutronics and thermal-hydraulic core analyses with the PARCS and RELAP5 codes, a preliminary NMR-50 core design has been developed to meet the 10-year cycle length with an average fuel enrichment of 4.75 wt% and a maximum enrichment of 5.0 wt%. The calculated fuel temperature coefficient and coolant void coefficient provide adequate negative reactivity feedbacks. The maximum fuel linear power density throughout the 10-year burn cycle is 18.7 kW/...
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experimental investigation of natural circulation instability in a bwr type Small Modular Reactor
Progress in Nuclear Energy, 2015Co-Authors: Joshua P Schlegel, Caleb S Brooks, Takashi Hibiki, Mamoru IshiiAbstract:Abstract The Purdue NMR (Novel Modular Reactor) represents a BWR-type Small Modular Reactor with a significantly reduced Reactor pressure vessel (RPV). Specifically, the NMR is one third the height and area of a conventional BWR RPV with an electrical output of 50 MWe. Experiments are performed in a well-scaled test facility to investigate the thermal hydraulic flow instabilities during the startup transients for the NMR. The scaling analysis for the design of natural circulation test facility uses a three-level scaling methodology. Scaling criteria are derived from non-dimensional field and constitutive equations. Important thermal hydraulic parameters, e.g. system pressure, inlet coolant flow velocity and local void fraction, are analyzed for slow and fast normal startup transients. Flashing instability and density wave oscillation are the main flow instabilities observed when system pressure is below 0.5 MPa. And the flashing instability and density wave oscillation show different type of oscillations in void fraction profile. Finally, the pressurized startup procedure is recommended and tested in current research to effectively eliminate the flow instabilities during the NMR startup transients.
Yonghee Kim - One of the best experts on this subject based on the ideXlab platform.
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truly optimized pwr lattice for innovative soluble boron free Small Modular Reactor
Scientific Reports, 2021Co-Authors: Xuan Ha Nguyen, Seongdong Jang, Yonghee KimAbstract:A novel re-optimization of fuel assembly and new innovative burnable absorber (BA) concepts are investigated in this paper to pursue a high-performance soluble-boron-free (SBF) Small Modular Reactor (SMR), named autonomous transportable on-demand Reactor module (ATOM). A truly optimized PWR (TOP) lattice concept has been introduced to maximize the neutron economy while enhancing the inherent safety of an SBF pressurized water Reactor. For an SBF SMR design, the 3-D centrally-shielded BA (CSBA) design is utilized and another innovative 3-D BA called disk-type BA (DiBA) is proposed in this study. Both CSBA and DiBA designs are investigated in terms of material, spatial self-shielding effects, and thermo-mechanical properties. A low-leakage two-batch fuel management is optimized for both conventional and TOP-based SBF ATOM cores. A combination of CSBA and DiBA is introduced to achieve a very Small reactivity swing (< 1000 pcm) as well as a long cycle length and high fuel burnup. For the SBF ATOM core, safety parameters are evaluated and the moderator temperature coefficient is shown to remain sufficiently and similarly negative throughout the whole cycle. It is demonstrated that the Small excess reactivity can be well managed by mechanical shim rods with a marginal increase in the local power peaking, and a cold-zero shutdown is possible with a pseudo checker-board control rod pattern. In addition, a thermal-hydraulic-coupled neutronic analysis of the ATOM core is discussed.
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Truly-optimized PWR lattice for innovative soluble-boron-free Small Modular Reactor
'Springer Science and Business Media LLC', 2021Co-Authors: Xuan Ha Nguyen, Seongdong Jang, Yonghee KimAbstract:Abstract A novel re-optimization of fuel assembly and new innovative burnable absorber (BA) concepts are investigated in this paper to pursue a high-performance soluble-boron-free (SBF) Small Modular Reactor (SMR), named autonomous transportable on-demand Reactor module (ATOM). A truly optimized PWR (TOP) lattice concept has been introduced to maximize the neutron economy while enhancing the inherent safety of an SBF pressurized water Reactor. For an SBF SMR design, the 3-D centrally-shielded BA (CSBA) design is utilized and another innovative 3-D BA called disk-type BA (DiBA) is proposed in this study. Both CSBA and DiBA designs are investigated in terms of material, spatial self-shielding effects, and thermo-mechanical properties. A low-leakage two-batch fuel management is optimized for both conventional and TOP-based SBF ATOM cores. A combination of CSBA and DiBA is introduced to achieve a very Small reactivity swing (
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impacts of an atf cladding on neutronic performances of the soluble boron free atom core
International Journal of Energy Research, 2020Co-Authors: Xuan Ha Nguyen, Seongdong Jang, Yonghee KimAbstract:The impacts of various ATF (accident tolerant fuel) claddings on neutronic performances of pressurized water Reactor fuel assembly and soluble‐boron‐free Small Modular Reactor autonomous transportable on‐demand Reactor module (ATOM) are investigated. There are two ATF cladding concepts which are evaluated here: (a) Coating Zircaloy‐4 cladding with thin layer of Cr or Cr alloys; (b) High‐strength and oxidation‐resistant claddings: SS‐304 and FeCrAl. A minor modification of burnable absorber loading in the ATOM core is proposed to adopt the selected ATF cladding and maintain the core performances.
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an advanced core design for a soluble boron free Small Modular Reactor atom with centrally shielded burnable absorber
Nuclear Engineering and Technology, 2019Co-Authors: Xuan Ha Nguyen, Chihyung Kim, Yonghee KimAbstract:Abstract A complete solution for a soluble-boron-free (SBF) Small Modular Reactor (SMR) is pursued with a new burnable absorber concept, namely centrally-shielded burnable absorber (CSBA). Neutronic flexibility of the CSBA design has been discussed with fuel assembly (FA) analyses. Major design parameters and goals of the SBF SMR are discussed in view of the Reactor core design and three CSBA designs are introduced to achieve both a very low burnup reactivity swing (BRS) and minimal residual reactivity of the CSBA. It is demonstrated that the core achieves a long cycle length (∼37 months) and high burnup (∼30 GWd/tU), while the BRS is only about 1100 pcm and the radial power distribution is rather flat. This research also introduces a supplementary reactivity control mechanism using stainless steel as mechanical shim (MS) rod to obtain the criticality during normal operation. A further analysis is performed to investigate the local power peaking of the CSBA-loaded FA at MS-rodded condition. Moreover, a simple B4C-based control rod arrangement is proposed to assure a sufficient shutdown margin even at the cold-zero-power condition. All calculations in this neutronic-thermal hydraulic coupled investigation of the 3D SBF SMR core are completed by a two-step Monte Carlo-diffusion hybrid methodology.
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An advanced core design for a soluble-boron-free Small Modular Reactor ATOM with centrally-shielded burnable absorber
Elsevier, 2019Co-Authors: Xuan Ha Nguyen, Chihyung Kim, Yonghee KimAbstract:A complete solution for a soluble-boron-free (SBF) Small Modular Reactor (SMR) is pursued with a new burnable absorber concept, namely centrally-shielded burnable absorber (CSBA). Neutronic flexibility of the CSBA design has been discussed with fuel assembly (FA) analyses. Major design parameters and goals of the SBF SMR are discussed in view of the Reactor core design and three CSBA designs are introduced to achieve both a very low burnup reactivity swing (BRS) and minimal residual reactivity of the CSBA. It is demonstrated that the core achieves a long cycle length (∼37 months) and high burnup (∼30 GWd/tU), while the BRS is only about 1100 pcm and the radial power distribution is rather flat. This research also introduces a supplementary reactivity control mechanism using stainless steel as mechanical shim (MS) rod to obtain the criticality during normal operation. A further analysis is performed to investigate the local power peaking of the CSBA-loaded FA at MS-rodded condition. Moreover, a simple B4C-based control rod arrangement is proposed to assure a sufficient shutdown margin even at the cold-zero-power condition. All calculations in this neutronic-thermal hydraulic coupled investigation of the 3D SBF SMR core are completed by a two-step Monte Carlo-diffusion hybrid methodology. Keywords: Small Modular Reactor, Soluble-boron-free (SBF), Centrally-shielded burnable absorber (CSBA), ATOM, Serpent-COREDA
Geoffrey T Parks - One of the best experts on this subject based on the ideXlab platform.
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neutronic feasibility of civil marine Small Modular Reactor core using mixed d2o h2o coolant
Nuclear Engineering and Design, 2020Co-Authors: Syed Bahauddin Alam, Dinesh Kumar, Bader Almutairi, Cameron S Goodwin, Sh Tanim, Safwan Jaradat, Kirk D Atkinson, Geoffrey T ParksAbstract:Abstract In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable that a civil marine core not to use highly enriched uranium, but it is then a challenge to achieve long core lifetime while maintaining reactivity control and acceptable power distributions in the core. The objective of this study is to design a civil marine core type of single batch Small Modular Reactor (SMR) with low enriched uranium (LEU) ( 20% 235U enrichment), a soluble-boron-free (SBF) and using mixed D 2 O + H 2 O coolant for operation period over a 20 years life at 333 MWth. Changing the coolant properties is the way to alter the neutron energy spectrum in order to achieve a self-sustaining core design of higher burnup. Two types of LEU fuels were used in this study: micro-heterogeneous ThO2-UO2 duplex fuel (18% 235U enriched) and all-UO2 fuel (15% 235U enriched). 2D Assembly designs are developed using WIMS and 3D whole-core model is developed using PANTHER code. The duplex option shows greater promise in the final burnable poison design with high thickness ZrB2 integral fuel burnable absorber (IFBA) while maintaining low, stable reactivity with minimal burnup penalty. For the final poison design with ZrB2, the duplex contributes ∼ 2.5% more initial reactivity suppression, although the all-UO2 design exhibits lower reactivity swing. Three types of candidate control rod materials: hafnium, boron carbide (B4C) and 80% silver + 15% indium + 5% cadmium (Ag-In-Cd) are examined and duplex fuel exhibits higher control rod worth with the candidate materials. B4C shows the greatest control reactivity worth for both the candidate fuels, providing ∼ 3% higher control rod worth for duplex fuel than all-UO2. Finally, 3D whole-core results from PANTHER show that the use of the mixed coolant contributes to ∼ 21.5 years core life, which is a ∼ 40% increase in core life compared to H 2 O coolant ( ∼ 15.5 years) while using the same fuel candidates and fissile enrichment. The mixed coolant provides excellent core lifetimes comparable to those of HEU military naval vessels ( ∼ 25 years vs. ∼ 21.5 years) while utilizing LEU candidate fuels.
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neutronic investigation of alternative composite burnable poisons for the soluble boron free and long life civil marine Small Modular Reactor cores
Scientific Reports, 2019Co-Authors: Syed Bahauddin Alam, Tuhfatur Ridwan, Dinesh Kumar, Bader Almutairi, Cameron S Goodwin, Kirk D Atkinson, Geoffrey T ParksAbstract:Concerns about the effects of global warming provide a strong case to consider how best nuclear power could be applied to marine propulsion. Currently, there are persistent efforts worldwide to com ...
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Small Modular Reactor core design for civil marine propulsion using micro heterogeneous duplex fuel part ii whole core analysis
Nuclear Engineering and Design, 2019Co-Authors: Syed Bahauddin Alam, Tuhfatur Ridwan, Dinesh Kumar, Bader Almutairi, Cameron S Goodwin, Geoffrey T ParksAbstract:Abstract Civil marine Reactors face a unique set of design challenges. These include requirements for a Small core size and long core lifetime, a 20% cap on fissile loading, and limitations on using soluble neutron absorbers. In this Reactor physics study, we seek to design a core that meets these requirements over a 15 effective full-power-years (EFPY) life at 333 MWth using homogeneously mixed all-UO2 and micro-heterogeneous ThO2-UO2 duplex fuels. In a companion (Part I) paper, we found assembly designs using 15% and 18% 235 U for UO2 and duplex fuels, respectively, loaded into 13 × 13 pin arrays. High thickness (150 μm) ZrB2 integral fuel burnable absorber (IFBA) pins and boron carbide (B4C) control rods are used for reactivity control. Taking advantage of self-shielding effects, these designs maintain low and stable assembly reactivity with little burnup penalty. In this paper (Part II), whole-core design analyses are performed for Small Modular Reactor (SMR) to determine whether the core remains critical for at least 15 EFPY with a reactivity swing of less than 4000 pcm, subject to appropriate constraints. The main challenge is to keep the radial form factor below its limit (1.50). Burnable poison radial-zoning is examined in the quest for a suitable arrangement to control power peaking. Optimized assemblies are loaded into a 3D Reactor model in PANTHER. The PANTHER results confirm that the fissile loadings of both fuels are well-designed for the target lifetime: at the end of the ∼ 15-year cycle, the cores are on the border of criticality. The duplex fuel core can achieve ∼ 4% longer core life, has a ∼ 3% lower initial reactivity and ∼ 30% lower reactivity swing over life than the final UO2 core design. The duplex core is therefore the more successful design, giving a core life of ∼ 16 years and a reactivity swing of less than 2500 pcm, while satisfying all the neutronic safety parameters. In particular, one of the major objectives of this study is to offer/explore a thorium-based candidate alternative fuel platform for the proposed marine core. It is proven by literature reviews that the ability of the duplex fuel was never explored in the context of a single-batch, LEU, SBF, long-life SMR core. In this regard, the motivation of this paper is to understand the underlying physics of the duplex fuel and ‘open the option’ of designing the functional cores with both the duplex and UO2 fuel cores.
Syed Bahauddin Alam - One of the best experts on this subject based on the ideXlab platform.
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quantitative risk assessment of a high power density Small Modular Reactor smr core using uncertainty and sensitivity analyses
Energy, 2021Co-Authors: Dinesh Kumar, Syed Bahauddin Alam, Tuhfatur Ridwan, Cameron S GoodwinAbstract:Abstract The use of uncertainty quantification and machine learning platforms in ensuring the robustness of Small Modular Reactor (or popularly known as SMR) core design is rare. Most importantly, there have not been many studies in SMR core design that need significant attention in terms of uncertainty quantification to ensure thermal-hydraulics safety. The majority of the previous SMR core studies have been limited to low core power density ( ∼ 60–65 MW/m3) environment, whereas typical land-based light-water cooled power Reactors are operated in ∼ 100 MW/m3. In this paper, we attempt to fill the major gap in the robustness of SMR design system by using advanced VVUQ (Verification, Validation, and Uncertainty Quantification) approaches. Therefore, this work addresses the uncertainty issue and quantifies the sensitivity for the 100 MW/m3 SMR core system. Non-intrusive polynomial chaos, an efficient, well-developed, and validated approach, is applied to a subchannel thermal-hydraulic SMR system to compute the effect of input uncertainties on the SMR core. The impact of input uncertainties for 10% variability is evaluated on the key thermal-hydraulic parameters in the hot channel for the SMR Reactor core with 100 MW/m3. It has been observed that all the output system parameters and their uncertainties are within the prescribed core safety limits for the 100 MW/m3 SMR core, except for the pressure drop and surface heat flux. It is also noticed that these two parameters exhibit an approximately 20% probability of exceeding the limiting values. The sensitivity analysis concluded that the pressure drop and surface heat flux are highly sensitive to the inlet temperature and linear power profile, respectively.
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neutronic feasibility of civil marine Small Modular Reactor core using mixed d2o h2o coolant
Nuclear Engineering and Design, 2020Co-Authors: Syed Bahauddin Alam, Dinesh Kumar, Bader Almutairi, Cameron S Goodwin, Sh Tanim, Safwan Jaradat, Kirk D Atkinson, Geoffrey T ParksAbstract:Abstract In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable that a civil marine core not to use highly enriched uranium, but it is then a challenge to achieve long core lifetime while maintaining reactivity control and acceptable power distributions in the core. The objective of this study is to design a civil marine core type of single batch Small Modular Reactor (SMR) with low enriched uranium (LEU) ( 20% 235U enrichment), a soluble-boron-free (SBF) and using mixed D 2 O + H 2 O coolant for operation period over a 20 years life at 333 MWth. Changing the coolant properties is the way to alter the neutron energy spectrum in order to achieve a self-sustaining core design of higher burnup. Two types of LEU fuels were used in this study: micro-heterogeneous ThO2-UO2 duplex fuel (18% 235U enriched) and all-UO2 fuel (15% 235U enriched). 2D Assembly designs are developed using WIMS and 3D whole-core model is developed using PANTHER code. The duplex option shows greater promise in the final burnable poison design with high thickness ZrB2 integral fuel burnable absorber (IFBA) while maintaining low, stable reactivity with minimal burnup penalty. For the final poison design with ZrB2, the duplex contributes ∼ 2.5% more initial reactivity suppression, although the all-UO2 design exhibits lower reactivity swing. Three types of candidate control rod materials: hafnium, boron carbide (B4C) and 80% silver + 15% indium + 5% cadmium (Ag-In-Cd) are examined and duplex fuel exhibits higher control rod worth with the candidate materials. B4C shows the greatest control reactivity worth for both the candidate fuels, providing ∼ 3% higher control rod worth for duplex fuel than all-UO2. Finally, 3D whole-core results from PANTHER show that the use of the mixed coolant contributes to ∼ 21.5 years core life, which is a ∼ 40% increase in core life compared to H 2 O coolant ( ∼ 15.5 years) while using the same fuel candidates and fissile enrichment. The mixed coolant provides excellent core lifetimes comparable to those of HEU military naval vessels ( ∼ 25 years vs. ∼ 21.5 years) while utilizing LEU candidate fuels.
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neutronic investigation of alternative composite burnable poisons for the soluble boron free and long life civil marine Small Modular Reactor cores
Scientific Reports, 2019Co-Authors: Syed Bahauddin Alam, Tuhfatur Ridwan, Dinesh Kumar, Bader Almutairi, Cameron S Goodwin, Kirk D Atkinson, Geoffrey T ParksAbstract:Concerns about the effects of global warming provide a strong case to consider how best nuclear power could be applied to marine propulsion. Currently, there are persistent efforts worldwide to com ...
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Small Modular Reactor core design for civil marine propulsion using micro heterogeneous duplex fuel part ii whole core analysis
Nuclear Engineering and Design, 2019Co-Authors: Syed Bahauddin Alam, Tuhfatur Ridwan, Dinesh Kumar, Bader Almutairi, Cameron S Goodwin, Geoffrey T ParksAbstract:Abstract Civil marine Reactors face a unique set of design challenges. These include requirements for a Small core size and long core lifetime, a 20% cap on fissile loading, and limitations on using soluble neutron absorbers. In this Reactor physics study, we seek to design a core that meets these requirements over a 15 effective full-power-years (EFPY) life at 333 MWth using homogeneously mixed all-UO2 and micro-heterogeneous ThO2-UO2 duplex fuels. In a companion (Part I) paper, we found assembly designs using 15% and 18% 235 U for UO2 and duplex fuels, respectively, loaded into 13 × 13 pin arrays. High thickness (150 μm) ZrB2 integral fuel burnable absorber (IFBA) pins and boron carbide (B4C) control rods are used for reactivity control. Taking advantage of self-shielding effects, these designs maintain low and stable assembly reactivity with little burnup penalty. In this paper (Part II), whole-core design analyses are performed for Small Modular Reactor (SMR) to determine whether the core remains critical for at least 15 EFPY with a reactivity swing of less than 4000 pcm, subject to appropriate constraints. The main challenge is to keep the radial form factor below its limit (1.50). Burnable poison radial-zoning is examined in the quest for a suitable arrangement to control power peaking. Optimized assemblies are loaded into a 3D Reactor model in PANTHER. The PANTHER results confirm that the fissile loadings of both fuels are well-designed for the target lifetime: at the end of the ∼ 15-year cycle, the cores are on the border of criticality. The duplex fuel core can achieve ∼ 4% longer core life, has a ∼ 3% lower initial reactivity and ∼ 30% lower reactivity swing over life than the final UO2 core design. The duplex core is therefore the more successful design, giving a core life of ∼ 16 years and a reactivity swing of less than 2500 pcm, while satisfying all the neutronic safety parameters. In particular, one of the major objectives of this study is to offer/explore a thorium-based candidate alternative fuel platform for the proposed marine core. It is proven by literature reviews that the ability of the duplex fuel was never explored in the context of a single-batch, LEU, SBF, long-life SMR core. In this regard, the motivation of this paper is to understand the underlying physics of the duplex fuel and ‘open the option’ of designing the functional cores with both the duplex and UO2 fuel cores.
Xuan Ha Nguyen - One of the best experts on this subject based on the ideXlab platform.
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truly optimized pwr lattice for innovative soluble boron free Small Modular Reactor
Scientific Reports, 2021Co-Authors: Xuan Ha Nguyen, Seongdong Jang, Yonghee KimAbstract:A novel re-optimization of fuel assembly and new innovative burnable absorber (BA) concepts are investigated in this paper to pursue a high-performance soluble-boron-free (SBF) Small Modular Reactor (SMR), named autonomous transportable on-demand Reactor module (ATOM). A truly optimized PWR (TOP) lattice concept has been introduced to maximize the neutron economy while enhancing the inherent safety of an SBF pressurized water Reactor. For an SBF SMR design, the 3-D centrally-shielded BA (CSBA) design is utilized and another innovative 3-D BA called disk-type BA (DiBA) is proposed in this study. Both CSBA and DiBA designs are investigated in terms of material, spatial self-shielding effects, and thermo-mechanical properties. A low-leakage two-batch fuel management is optimized for both conventional and TOP-based SBF ATOM cores. A combination of CSBA and DiBA is introduced to achieve a very Small reactivity swing (< 1000 pcm) as well as a long cycle length and high fuel burnup. For the SBF ATOM core, safety parameters are evaluated and the moderator temperature coefficient is shown to remain sufficiently and similarly negative throughout the whole cycle. It is demonstrated that the Small excess reactivity can be well managed by mechanical shim rods with a marginal increase in the local power peaking, and a cold-zero shutdown is possible with a pseudo checker-board control rod pattern. In addition, a thermal-hydraulic-coupled neutronic analysis of the ATOM core is discussed.
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Truly-optimized PWR lattice for innovative soluble-boron-free Small Modular Reactor
'Springer Science and Business Media LLC', 2021Co-Authors: Xuan Ha Nguyen, Seongdong Jang, Yonghee KimAbstract:Abstract A novel re-optimization of fuel assembly and new innovative burnable absorber (BA) concepts are investigated in this paper to pursue a high-performance soluble-boron-free (SBF) Small Modular Reactor (SMR), named autonomous transportable on-demand Reactor module (ATOM). A truly optimized PWR (TOP) lattice concept has been introduced to maximize the neutron economy while enhancing the inherent safety of an SBF pressurized water Reactor. For an SBF SMR design, the 3-D centrally-shielded BA (CSBA) design is utilized and another innovative 3-D BA called disk-type BA (DiBA) is proposed in this study. Both CSBA and DiBA designs are investigated in terms of material, spatial self-shielding effects, and thermo-mechanical properties. A low-leakage two-batch fuel management is optimized for both conventional and TOP-based SBF ATOM cores. A combination of CSBA and DiBA is introduced to achieve a very Small reactivity swing (
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impacts of an atf cladding on neutronic performances of the soluble boron free atom core
International Journal of Energy Research, 2020Co-Authors: Xuan Ha Nguyen, Seongdong Jang, Yonghee KimAbstract:The impacts of various ATF (accident tolerant fuel) claddings on neutronic performances of pressurized water Reactor fuel assembly and soluble‐boron‐free Small Modular Reactor autonomous transportable on‐demand Reactor module (ATOM) are investigated. There are two ATF cladding concepts which are evaluated here: (a) Coating Zircaloy‐4 cladding with thin layer of Cr or Cr alloys; (b) High‐strength and oxidation‐resistant claddings: SS‐304 and FeCrAl. A minor modification of burnable absorber loading in the ATOM core is proposed to adopt the selected ATF cladding and maintain the core performances.
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an advanced core design for a soluble boron free Small Modular Reactor atom with centrally shielded burnable absorber
Nuclear Engineering and Technology, 2019Co-Authors: Xuan Ha Nguyen, Chihyung Kim, Yonghee KimAbstract:Abstract A complete solution for a soluble-boron-free (SBF) Small Modular Reactor (SMR) is pursued with a new burnable absorber concept, namely centrally-shielded burnable absorber (CSBA). Neutronic flexibility of the CSBA design has been discussed with fuel assembly (FA) analyses. Major design parameters and goals of the SBF SMR are discussed in view of the Reactor core design and three CSBA designs are introduced to achieve both a very low burnup reactivity swing (BRS) and minimal residual reactivity of the CSBA. It is demonstrated that the core achieves a long cycle length (∼37 months) and high burnup (∼30 GWd/tU), while the BRS is only about 1100 pcm and the radial power distribution is rather flat. This research also introduces a supplementary reactivity control mechanism using stainless steel as mechanical shim (MS) rod to obtain the criticality during normal operation. A further analysis is performed to investigate the local power peaking of the CSBA-loaded FA at MS-rodded condition. Moreover, a simple B4C-based control rod arrangement is proposed to assure a sufficient shutdown margin even at the cold-zero-power condition. All calculations in this neutronic-thermal hydraulic coupled investigation of the 3D SBF SMR core are completed by a two-step Monte Carlo-diffusion hybrid methodology.
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An advanced core design for a soluble-boron-free Small Modular Reactor ATOM with centrally-shielded burnable absorber
Elsevier, 2019Co-Authors: Xuan Ha Nguyen, Chihyung Kim, Yonghee KimAbstract:A complete solution for a soluble-boron-free (SBF) Small Modular Reactor (SMR) is pursued with a new burnable absorber concept, namely centrally-shielded burnable absorber (CSBA). Neutronic flexibility of the CSBA design has been discussed with fuel assembly (FA) analyses. Major design parameters and goals of the SBF SMR are discussed in view of the Reactor core design and three CSBA designs are introduced to achieve both a very low burnup reactivity swing (BRS) and minimal residual reactivity of the CSBA. It is demonstrated that the core achieves a long cycle length (∼37 months) and high burnup (∼30 GWd/tU), while the BRS is only about 1100 pcm and the radial power distribution is rather flat. This research also introduces a supplementary reactivity control mechanism using stainless steel as mechanical shim (MS) rod to obtain the criticality during normal operation. A further analysis is performed to investigate the local power peaking of the CSBA-loaded FA at MS-rodded condition. Moreover, a simple B4C-based control rod arrangement is proposed to assure a sufficient shutdown margin even at the cold-zero-power condition. All calculations in this neutronic-thermal hydraulic coupled investigation of the 3D SBF SMR core are completed by a two-step Monte Carlo-diffusion hybrid methodology. Keywords: Small Modular Reactor, Soluble-boron-free (SBF), Centrally-shielded burnable absorber (CSBA), ATOM, Serpent-COREDA
