Decay heat (DH) is the heat produced through a radioactive decay of fission products during or after a reactor operation. It is known as the second largest source of power in the core after fission. ...Being such a strong contributor to reactor power, it should be accurately determined at any time of reactor operation. Currently, there are two main approaches for DH estimation used in reactor simulation codes. One approach is based on careful inventorying of all produced target nuclides and their individual contributions to total power. Alternatively, the other popular approach is based on collapsing all target fission products into a small number of groups similar to delayed neutron estimation techniques. However, the last (multigroup) method currently has limitations when used in some transient scenarios such as transients occurred in fresh fuel.
In this study, the multigroup method was further developed for reducing limitations while retaining the advantage in computation speed. Then, it was implemented into Reactor Analysis code for Steady state and Transient (RAST-K) and tested against other codes. As a result, the improved method was found capable of determining DH power at all tested stages of reactor operation under any tested operation scenario. In particular, the test simulations using the improved method showed better results in those scenarios that were under accuracy limitations of the original multigroup method. Overall, the quality of transient calculations in RAST-K was improved when using the newly implemented DH module.
This study aimed to verify and validate the transient simulation capability of the hybrid code system RAST-F for fast reactor analysis. For this purpose, control rod (CR) drop experiments involving ...eight separate CRs and six CR groups in the China Experimental Fast Reactor (CEFR) start-up tests were utilized to simulate the CR drop transient. The RAST-F numerical solution, including the neutron population, time-dependent reactivity, and CR worth, was compared against the measurement values obtained from two out-of-core detectors. Moreover, the time-dependent reactivity and CR worth from RAST-F were verified against the results obtained by the Monte Carlo code Serpent using continuous energy nuclear data. A code-to-code comparison between Serpent and RAST-F showed good agreement in terms of time-dependent reactivity and CR worth. The discrepancy was less than 160 pcm for reactivity and less than 110 pcm for CR worth. RAST-F solution was almost identical to the measurement data in terms of neutron population and reactivity. All the calculated CR worth results agreed with experimental results within two standard deviations of experimental uncertainty for all CRs and CR groups. This work demonstrates that the RAST-F code system can be a potential tool for analyzing time-dependent phenomena in fast reactors.
The feasibility of using the Monte Carlo code MCS to generate multigroup cross sections for nodal diffusion simulations RAST-F of liquid metal fast reactors is investigated in this paper. The ...performance of the MCS/RAST-F code system is assessed using steady-state simulations of the ANTS-100e core. The results show good agreement between MCS/RAST-F and MCS reference solutions, with a keff difference of less than 77 pcm and root-mean-square differences in radial and axial power of less than 0.5% and 0.25%, respectively. Furthermore, the MCS/RAST-F reactivity feedback coefficients are within three standard deviations of the MCS coefficients. To validate the internal thermal-hydraulic (TH) feedback capability in RAST-F code, the coupled neutronic/TH1D simulation of ANTS-100e is performed using the case matrix obtained from MCS branch calculations. The results are compared to those obtained using the MARS-LBE system code and show good agreement with relative temperature differences in fuel and coolant of less than 0.8%. This study demonstrates that the MCS/RAST-F code system can produce accurate results for core steady-state neutronic calculations and for coupled neutronic/TH simulations.
The Tapirus indicus, also known as Malayan tapir, has been listed as a rapidly declining animal species in the past decades, along with being declared and categorized as an endangered species by the ...International Union for Conservation of Nature (IUCN) 2016. This tapir species is geographically distributed across several countries in Southeast Asia such as Peninsular Malaysia, Indonesia (Sumatra), South Thailand, and Myanmar. Amongst these countries, the Peninsula Malaysia forest is recorded to contain the highest number of Malayan tapir population. Unfortunately, in the past decades, the population of Malayan tapirs has declined swiftly due to serious deforestation, habitat fragmentation, and heavy vehicle accidents during road crossings at forest routes. Concerned by this predicament, the Department of Wildlife and National Parks (DWNP) Peninsular Malaysia collaborated with a few local universities to conduct various studies aimed at increasing the population number of tapirs in Malaysia. Several studies were conducted with the aim of enhancing the well-being of tapirs in captivity. Veterinarians face problems when it comes to selecting healthy and suitable tapirs for breeding programs at conservation centers. Conventional molecular methods using high-throughput sequencing provides a solution in determining the health condition of Malayan tapirs using the Next-Generation Sequencing (NGS) technology. Unaware by most, gut microbiome plays an important role in determining the health condition of an organism by various aspects: (1) digestion control; (2) benefiting the immune system; and (3) playing a role as a "second brain." Commensal gut bacterial communities (microbiomes) are predicted to influence organism health and disease. Imbalance of unhealthy and healthy microbes in the gut may contribute to weight gain, high blood sugar, high cholesterol, and other disorders. In infancy, neonatal gut microbiomes are colonized with maternal and environmental flora, and mature toward a stable composition in two to three years. Interactions between the microorganism communities and the host allow for the establishment of microbiological roles. Identifying the core microbiome(s) are essential in the prediction of diseases and changes in environmental behavior of microorganisms. The dataset of 16S rRNA amplicon sequencing of Malayan tapir was deposited in the MG-RAST portal. Parameters such as quality control, taxonomic prediction (unknown and predicted), diversity (rarefaction), and diversity (alpha) were analyzed using sequencing approaches (Amplicon sequencing). Comparisons of parameters, according to the type of sequencing, showed significant differences, except for the prediction variable. In the Amplicon sequencing datasets, the parameters Rarefaction and Unknown had the highest correlation, while Alpha and Predicted had the lowest. Firmicutes, Bacteroidetes, Proteobacteria, Bacilli, and Bacteroidia were the most representative genera in Malayan tapir amplicon sequences, which indicated that most of the tapirs were healthy. However, continuous assessment to maintain the well-being of tapir for long term is still required. This chapter focuses on the introduction of 16S rRNA amplicon metagenomics in analyzing Malayan tapir gut microbiome dataset.
This paper presents the verification and validation (V&V) of the STREAM/RAST-K 2.0 code system for a pressurized water reactor (PWR) analysis. A lattice physics code STREAM and a nodal diffusion code ...RAST-K 2.0 have been developed by a computational reactor physics and experiment laboratory (CORE) of Ulsan National Institute of Science and Technology (UNIST) for an accurate two-step PWR analysis. The calculation modules of each code were already verified against various benchmark problems, whereas this paper focuses on the V&V of linked code system. Three PWR type reactor cores, OPR-1000, three-loop Westinghouse reactor core, and APR-1400, are selected as V&V target plants. This code system, for verification, is compared against the conventional code systems used for the calculations in nuclear design reports (NDRs) and validated against measured plant data. Compared parameters are as follows: critical boron concentration (CBC), axial shape index (ASI), assembly-wise power distribution, burnup distribution and peaking factors. STREAM/RAST-K 2.0 shows the RMS error of critical boron concentration within 20 ppm, and the RMS error of assembly power within 1.34% for all the cycles of all reactors. Keywords: Verification and validation, PWR core, Two-step approach, STREAM, RAST-K 2.0
The objective of this study was to provide the clinic with rapid and accurate results of antimicrobial susceptibility testing for the treatment of patients with bloodstream infections. To achieve ...this, we applied the Clinical and Laboratory Standards Institute (CLSI) blood culture direct rapid antimicrobial susceptibility test (rAST) to assess the susceptibility of the most common Enterobacterales found in blood cultures.
In this study, we utilized the CLSI blood culture direct rapid antimicrobial susceptibility test to assess the susceptibility (rAST) of the most common Enterobacterales present in blood cultures. We chose this method for its simplicity in analysis, and our aim was to predict minimum inhibitory concentrations (MICs) using the rAST. As a benchmark, we assumed that Broth Macrodilution method (BMD) results were 100% accurate. For data evaluation, we employed the terms categorical agreement (CA), very major errors (VME), and major errors (ME).
Our findings demonstrate that the CLSI rAST method is reliable for rapidly determining the in vitro susceptibility of Enterobacterales to common antimicrobial drugs in bloodstream infections. We achieved a concordance rate of 90% in classification within a 10-hour timeframe. We identified a total of 112 carbapenem-resistant Enterobacterales (CRE) strains, and there was no significant difference in the detection rate of CRE at 6, 10, and 16 hours. This suggests that CRE can be identified as early as 6 hours.
The CLSI rAST is a valuable tool that can be utilized in clinical practice to quickly determine the susceptibility of Enterobacterales to antimicrobial drugs within 10 hours. This capability can greatly assist in the clinical management of patients with bloodstream infections.
CEFR is a small core-size sodium-cooled fast reactor (SFR) using high enrichment fuel with stainless-steel reflectors, which brings a significant challenge to the deterministic methodologies due to ...the strong spectral effect. The neutronic simulation of the start-up experiments conducted at the CEFR have been performed with a deterministic code system RAST-F, which is based on the two-step approach that couples a multi-group cross-section generation Monte-Carlo (MC) code and a multi-group nodal diffusion solver. The RAST-F results were compared against the measurement data. Moreover, the characteristic of neutron spectrum in the fuel rings, and adjacent reflectors was evaluated using different models for generation of accurate nuclear libraries. The numerical solution of RAST-F system was verified against the full core MC solution MCS at all control rods fully inserted and withdrawn states. A good agreement between RAST-F and MCS solutions was observed with less than 120 pcm discrepancies and 1.2% root-mean-square error in terms of keff and power distribution, respectively. Meanwhile, the RAST-F result agreed well with the experimental values within two-sigma of experimental uncertainty. The good agreement of these results indicating that RAST-F can be used to neutronic steady-state simulations for small core-size SFR, which was challenged to deterministic code system.
The aim of study was to compare the anaerobic capacity of different type sport. The running-based anaerobic capacity test (RAST) were exam to 42 athletes of football (10), sprint (6), takraw (8), ...volleyball (10) and pencak silat (8). The anova analysis resulted the difference of minimum power (MinP) (p=0.001), maximum power (MaxP) (p=0.000), average power (AvP)(0.000) and fatigue index (FI) (0.008). The post hoc analysis showed no difference anaerobic capacity between athletes of football vs sprinter, football vs pencak silat, football vs takraw and takraw vs pencak silat. The different finding appeared between athlete of volleyball vs the other athletes. and between takraw vs sprint. We concluded that the anaerobic capacity of athletes was specific with the type of sports.