scholarly journals HIGH-PERFORMANCE MULTI-BATCH FUEL MANAGEMENTS FOR THE ADVANCED SOLUBLE-BORON-FREE ATOM CORE

2021 ◽  
Vol 247 ◽  
pp. 19003
Author(s):  
Xuan Ha Nguyen ◽  
Seongdong Jang ◽  
Yonghee Kim

The autonomous transportable on-demand reactor module (ATOM), a 450 MWth PWR-type small modular reactor (SMR), is under development at Korea Advanced Institute of Science and Technology (KAIST). The ATOM core is designed for soluble-boron-free and passive autonomous load-following operations by utilizing successfully an advanced reactivity control technology, centrally-shielded burnable absorber (CSBA). To enhance the ATOM core safety, CrAl-coated Zircaloy-4 is adopted as an accident-tolerant-fuel cladding. For a long operational cycle, the reference ATOM core has primarily accomplished with a single-batch fuel management (FM). In this paper, for more flexible operation and enhanced fuel utilization, various multi-batch FMs are investigated while the core performance is maintained in terms of both neutronic and safety aspects. These aspects are refueling pattern, cycle length, burnup reactivity swing, discharge burnup, axial and radial power peaking factor (PPF), total PPF, and temperature coefficients. Several refueling types are examined: In-out (low leakage), out-in (flattened power), and randomly scattered schemes. In addition, new heavy reflector designs, ZrO2 and PbO, are introduced instead of stainless steel reflector for an improved core performance. Moreover, a new CSBA loading pattern is also proposed for an effective reactivity control of multi-batch FM strategy. Numerical results show that with a two-batch FM the cycle length can achieve above 2 years with an average discharge burnup of 40 GWd/tU, while the burnup reactivity swing remains less than 1,200 pcm. On top of that, the coolant and fuel temperature coefficients are highly negative at the beginning of cycle and power profile is comparable to that with the single-batch FM. All calculations in these multi-physics assessments of the ATOM core are performed using a Monte Carlo-diffusion hybrid code system based on Monte Carlo Serpent 2 and nodal diffusion COREDAX codes.

2021 ◽  
Author(s):  
Xuan Ha Nguyen ◽  
Seongdong Jang ◽  
Yonghee Kim

Abstract A novel re-optimization of fuel assembly (FA) 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 (<1,000 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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xuan Ha Nguyen ◽  
Seongdong Jang ◽  
Yonghee Kim

AbstractA 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.


2013 ◽  
Vol 1538 ◽  
pp. 291-302
Author(s):  
Edward Yi Chang ◽  
Hai-Dang Trinh ◽  
Yueh-Chin Lin ◽  
Hiroshi Iwai ◽  
Yen-Ku Lin

ABSTRACTIII-V compounds such as InGaAs, InAs, InSb have great potential for future low power high speed devices (such as MOSFETs, QWFETs, TFETs and NWFETs) application due to their high carrier mobility and drift velocity. The development of good quality high k gate oxide as well as high k/III-V interfaces is prerequisite to realize high performance working devices. Besides, the downscaling of the gate oxide into sub-nanometer while maintaining appropriate low gate leakage current is also needed. The lack of high quality III-V native oxides has obstructed the development of implementing III-V based devices on Si template. In this presentation, we will discuss our efforts to improve high k/III-V interfaces as well as high k oxide quality by using chemical cleaning methods including chemical solutions, precursors and high temperature gas treatments. The electrical properties of high k/InSb, InGaAs, InSb structures and their dependence on the thermal processes are also discussed. Finally, we will present the downscaling of the gate oxide into sub-nanometer scale while maintaining low leakage current and a good high k/III-V interface quality.


Animals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1104
Author(s):  
Emilio Fernández-Varón ◽  
Edgar García-Romero ◽  
Juan M. Serrano-Rodríguez ◽  
Carlos M. Cárceles ◽  
Ana García-Galán ◽  
...  

Contagious agalactia is a mycoplasmosis affecting small ruminants that have become an important issue in many countries. However, PK/PD studies of antibiotics to treat this problem in lactating goats affected by Mycoplasma (M.) agalactiae, the main CA-causing mycoplasma are almost non-existent. The aims of this study were to evaluate the plasma and milk disposition of marbofloxacin in lactating goats after intravenous (IV), subcutaneous (SC) and subcutaneous poloxamer P407 formulations with and without carboxy-methylcellulose (SC-P407-CMC and SC-P407) administration. Marbofloxacin concentrations were analysed by the High Performance Liquid Chromatography (HPLC) method. Minimum inhibitory concentrations (MIC) of M. agalactiae field isolates from mastitic goat’s milk were used to calculate surrogate markers of efficacy. Terminal half-lives of marbofloxacin after IV, SC, SC-P407 and SC-P407-CMC administration were 7.12, 6.57, 13.92 and 12.19 h in plasma, and the half-lives of elimination of marbofloxacin in milk were 7.22, 7.16, 9.30 and 7.74 h after IV, SC, SC-P407 and SC-P407-CMC administration, respectively. Marbofloxacin penetration from the blood into the milk was extensive, with Area Under the Curve (AUCmilk/AUCplasma) ratios ranged 1.04–1.23, and maximum concentrations (Cmax-milk/Cmax-plasma) ratios ranged 0.72–1.20. The PK/PD surrogate markers of efficacy fAUC24/MIC and the Monte Carlo simulation show that marbofloxacin ratio (fAUC24/MIC > 125) using a 90% of target attainment rate (TAR) need a dose regimen between 8.4 mg/kg (SC) and 11.57 mg/kg (P407CMC) and should be adequate to treat contagious agalactia in lactating goats.


2020 ◽  
Vol 21 (1) ◽  
pp. 147-156
Author(s):  
Fred Thomas Tracy ◽  
Jodi L. Ryder ◽  
Martin T. Schultz ◽  
Ghada S. Ellithy ◽  
Benjamin R. Breland ◽  
...  

The purpose of this research is to compare the results from two different computer programs of flow analysesof two levees at Port Arthur, Texas where rising water of a flood from Hurricane Ike occurred on the levees. The first program (Program 1) is a two-dimensional (2-D) transient finite element program that couples the conservation of mass flow equation with accompanying hydraulic boundary conditions with the conservation of force equations with accompanying x and y displacement and force boundary conditions, thus yielding total head, x displacement, and y displacement as unknowns at each finite element node. The second program (Program 2) is a 2-D transient finite element program that considers only the conservation of mass flowequation with its accompanying hydraulic boundary conditions, yielding only total head as the unknown at each finite element node. Compressive stresses can be computed at the centroid of each finite element when using the coupled program. Programs 1 and 2 were parallelized for high performance computing to consider thousands of realisations of the material properties. Since a single realisation requires as much as one hour of computer time for certain levees, the large realisation computation is made possible by utilising HPC. This Monte Carlo type analysis was used to compute the probability of unsatisfactory performance for under seepage, through seepage, and uplift for the two levees. Respective hydrographs from the flood resulting from Hurricane Ike were applied to each levee. When comparing the computations from the two programs, the most significant result was the two programs yielded significantly different values in the computed results in the two clay levees considered in this research.  


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Florin Pop

Modern physics is based on both theoretical analysis and experimental validation. Complex scenarios like subatomic dimensions, high energy, and lower absolute temperature are frontiers for many theoretical models. Simulation with stable numerical methods represents an excellent instrument for high accuracy analysis, experimental validation, and visualization. High performance computing support offers possibility to make simulations at large scale, in parallel, but the volume of data generated by these experiments creates a new challenge for Big Data Science. This paper presents existing computational methods for high energy physics (HEP) analyzed from two perspectives: numerical methods and high performance computing. The computational methods presented are Monte Carlo methods and simulations of HEP processes, Markovian Monte Carlo, unfolding methods in particle physics, kernel estimation in HEP, and Random Matrix Theory used in analysis of particles spectrum. All of these methods produce data-intensive applications, which introduce new challenges and requirements for ICT systems architecture, programming paradigms, and storage capabilities.


2014 ◽  
Vol 13 (02) ◽  
pp. 1450012 ◽  
Author(s):  
Manorama Chauhan ◽  
Ravindra Singh Kushwah ◽  
Pavan Shrivastava ◽  
Shyam Akashe

In the world of Integrated Circuits, complementary metal–oxide–semiconductor (CMOS) has lost its ability during scaling beyond 50 nm. Scaling causes severe short channel effects (SCEs) which are difficult to suppress. FinFET devices undertake to replace usual Metal Oxide Semiconductor Field Effect Transistor (MOSFETs) because of their better ability in controlling leakage and diminishing SCEs while delivering a strong drive current. In this paper, we present a relative examination of FinFET with the double gate MOSFET (DGMOSFET) and conventional bulk Si single gate MOSFET (SGMOSFET) by using Cadence Virtuoso simulation tool. Physics-based numerical two-dimensional simulation results for FinFET device, circuit power is presented, and classifying that FinFET technology is an ideal applicant for low power applications. Exclusive FinFET device features resulting from gate–gate coupling are conversed and efficiently exploited for optimal low leakage device design. Design trade-off for FinFET power and performance are suggested for low power and high performance applications. Whole power consumptions of static and dynamic circuits and latches for FinFET device, believing state dependency, show that leakage currents for FinFET circuits are reduced by a factor of over ~ 10X, compared to DGMOSFET and ~ 20X compared with SGMOSFET.


Sign in / Sign up

Export Citation Format

Share Document