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This paper presents a high performance burnable absorber named as CIMBA (Cylindrically Inserted and Mechanically Separated Burnable Absorber) for the soluble-boron-free SMR. The CIMBA is the cylindrical gadolinia inserted into the annular fuel pellets. Although the CIMBA utilizes the spatial self-shielding effect of the fuel material, a large reactivity upswing occurs when the gadolinia is depleted. To minimize the reactivity swing of the CIMBA-loaded FA, two approaches were investigated. One is controlling the spatial self-shielding effect of the CIMBA as burnup proceeds by a multi-layered structure of the CIMBA (ML-CIMBA) and the other is the mixed-loading of two different types of CIMBA (MIX-CIMBA). Both approaches show promising performances to minimize the reactivity swing, where the MIX-CIMBA is more preferable due to its simpler fabrication process. In conclusion, the MIX-CIMBA is expected to accelerate the commercialization of the CIMBA and can be used to achieve an optimal soluble-boron-free SMR core design.

The selection of an appropriate turbulence/transition model is critical when simulating the hypersonic flows based on the Reynolds-averaged Navier–Stokes (RANS) equation. In particular, a deep understanding of the validity, reliability, and limitations of existing models is an essential prerequisite to facilitate their further development. This paper reports on the assessment of two models dedicated to hypersonic boundary layer transition analysis. Both models are compared with two other models that are widely used in this field. The double ramp and shock wave laboratory scramjet intake cases are used for the validation and evaluation of the predictive performance of both models via comparison against experimental data. The results reveal that the appropriate selection of the transition model is critical to the attainment of accurate results. Moreover, the forebody of the scramjet combustion propulsion-01 (SCP-01) flight vehicle, which is a research model, is analyzed as a case study. The air intake performance of the SCP-01, as predicted by four models, is compared and analyzed at different flight altitude and Mach number conditions. The results reveal that the accuracy of the prediction of boundary layer and separated flow transitions significantly affects the flow field and corresponding air intake performance. Furthermore, the uncertainty of results obtained using the two models increases significantly with an increase in altitude. Finally, the reliability and limitations of the transition models considered in this study are examined.

We develop a new high-fidelity multiphysics model to simulate boron chemistry in the porous Chalk River Unidentified Deposit (CRUD) deposits. Heat transfer, capillary flow, solute transport, and chemical reactions are fully coupled. The evaporation of coolant in the deposits is included in governing equations modified by the volume-averaged assumption of wick boiling. The axial offset anomaly (AOA) of the Seabrook nuclear power plant is simulated. The new model reasonably predicts the distributions of temperature, pressure, velocity, volumetric boiling heat density, and chemical concentrations. In the thicker CRUD regions, 60% of the total heat is removed by evaporative heat transfer, causing boron species accumulation. The new model successfully shows the quantitative effect of coolant evaporation on the local distributions of boron. The total amount of boron in the CRUD layer increases by a factor of 1.21 when an evaporation-driven increase of soluble and precipitated boron concentrations is reflected. In addition, the concentrations of B(OH)3 and LiBO2 are estimated according to various conditions such as different CRUD thickness and porosity. At the end of the cycle in the AOA case, the total mass of boron incorporated in CRUD deposits of a reference single fuel rod is estimated to be about 0.5 mg.

Parabens are widely used preservatives in cosmetics and pharmaceutical products and are approved as food additives. These chemicals have been considered safe for many years. However, the literature classifies parabens as endocrine-disrupting chemicals, and an assessment of their influence on the endocrine system and systemic toxicity is important. This study explored long-term systemic toxicity, effects on the endocrine system, and toxicokinetic behavior after repeated subcutaneous administration of butylparaben to Sprague-Dawley rats. Rats were treated with vehicle (4% Tween 80) or butylparaben at dose levels of 2, 10, and 50 mg/kg/day for 13 weeks. Assessment of systemic toxicity and endocrine-disrupting effects was based on mortality; clinical signs; body weight; food and water consumption; ophthalmological findings; urinalysis; hematology and clinical biochemistry; organ weights; necropsy and histopathological findings; regularity and length of the estrous cycle; semen quality; and toxicokinetic behavior. Female uterine weight and estrous cycle, and male semen quality indicated no estrogenic effects. Butylparaben induced local irritation at the injection site in both sexes at a dose of 50 mg/kg/day, but systemic toxicity was not observed. Therefore, the no-observed-adverse-effect level of butylparaben is set at 50 mg/kg/day in rats of both sexes. Butylparaben was without endocrine system effects at this dose. Butylparaben displays dose-dependent systemic exposure up to the maximum dose of 50 mg/kg/day and repeated administration of butylparaben for 13 weeks shows no bioaccumulation.

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

This paper presents the verification and validation of the radiation source term calculation capability implemented in the reactor analysis code STREAM for pressurized water reactor (PWR) spent nuclear fuel (SNF) analysis. Activity, decay heat, neutron and gamma source spectra of irradiated PWR fuel assemblies are calculated with STREAM and ORIGEN and the results obtained are compared. The verification is performed with Westinghouse 15 × 15, 17 × 17 and Combustion Engineering 16 × 16 designs with enrichment of 3–5 wt.% 235U, burnup of 30–60 GWd/t and cooling times of 0.3–1000 years. The radiation source term comparison between STREAM and ORIGEN indicates that the implementation of the source term equations is correct. The validation is done by comparing STREAM calculation results against 91 decay heat calorimetric measurements for 52 PWR fuel assemblies performed at the Swedish central storage facility for spent nuclear fuel, CLAB, and United States Hanford Engineering Development Laboratory (HEDL) and General Electric Morris Operations. The measured fuel assemblies have enrichment of 2–4 wt.% 235U, burnup of 28–51 GWd/t and cooling times of 2–27 years. The comparison between calculated and measured decay heat shows good agreement. For most of the measurements analyzed, the calculated decay heat is within the range of the measurement uncertainty. The average, overall C/E over 71 CLAB decay heat measurements is 1.000 ± 0.017, and 0.997 ± 0.013 for 20 US measurements. Overall, this work demonstrates that STREAM can be reliably used to predict PWR SNF radiation source terms.

Background Studies have shown that short‐term exposure to air pollution is associated with cardiac arrhythmia hospitalization and mortality. However, the relationship between long‐term particulate matter air pollution and arrhythmias is still unclear. We evaluate the prospective association between particulate matter (PM) air pollution and the risk of incident arrhythmia and its subtypes. Methods and Results Participants were drawn from a prospective cohort study of 178 780 men and women who attended regular health screening exams in Seoul and Suwon, South Korea, from 2002 to 2016. Exposure to PM with an aerodynamic diameter of ≤10 and ≤2.5 μm (PM 10 and PM 2.5 , respectively) was estimated using a land‐use regression model. The associations between long‐term PM air pollution and arrhythmia were examined using pooled logistic regression models with time‐varying exposure and covariables. In the fully adjusted model, the odds ratios (ORs) for any arrhythmia associated with a 10 μg/m 3 increase in 12‐, 36‐, and 60‐month PM 10 exposure were 1.15 (1.09, 1.21), 1.12 (1.06, 1.18), and 1.14 (1.08, 1.20), respectively. The ORs with a 10 μg/m 3 increase in 12‐ and 36‐month PM 2.5 exposure were 1.27 (1.15, 1.40) and 1.10 (0.99, 1.23). PM 10 was associated with increased risk of incident bradycardia and premature atrial contraction. PM 2.5 was associated with increased risk of incident bradycardia and right bundle‐branch block. Conclusions In this large cohort study, long‐term exposure to outdoor PM air pollution was associated with increased risk of arrhythmia. Our findings indicate that PM air pollution may be a contributor to cardiac arrhythmia in the general population.

Background & Aims Although coronavirus disease 2019 (COVID-19) is characterized by fever and respiratory symptoms, some patients have no or mild symptoms. Severe acute respiratory syndrome-coronavirus (SARS-CoV-2) has been detected in feces of patients. We investigated gastrointestinal symptoms and shedding of virus into feces of patients with asymptomatic or mild COVID-19. Methods We collected data from 46 patients (median age, 26 y; 46% men) with asymptomatic or mild COVID-19 (without fever and pneumonia) and prolonged respiratory shedding of SARS-CoV-2, quarantined from April 4, 2020, through April 24, 2020, in Korea. Respiratory specimens included upper respiratory specimens (nasopharyngeal and oropharyngeal swabs) and lower respiratory specimens (sputum), and were collected twice per week. The median interval between COVID-19 diagnosis to the start of fecal sample collection was 37 days (range, 29–41 d); 213 stool specimens were collected from 46 patients. We used real-time reverse-transcription polymerase chain reaction to detect SARS-CoV-2 in the respiratory and fecal specimens. Results Gastrointestinal manifestations were observed in 16 of the 46 patients (35%); diarrhea was the most common (15%), followed by abdominal pain (11%), dyspepsia (11%), and nausea (2%). Virus RNA was detected in feces from 2 patients without gastrointestinal symptoms (4%). Mean cycle threshold values from the time of quarantine to the time of fecal collection tended to be lower in patients with virus detected in fecal samples than in patients without virus in fecal samples (29.91 vs 33.67 in the first week, 29.47 vs 35.71 in the fifth week, respectively). Shedding of virus into feces persisted until day 50 after diagnosis; fecal samples began to test negative before or at approximately the time that respiratory specimens also began to test negative. Conclusions In an analysis of fecal and respiratory specimens from patients with COVID-19 in quarantine in Korea, we found that the gastrointestinal tract could be a route of transmission of SARS-CoV-2 even in patients with asymptomatic or mild disease, with no gastrointestinal symptoms. The viral load of the respiratory specimens appears be related to shedding of the virus into feces in this group of patients.

The status of nuclear power plants’ conditions must be checked to avoid initial events which may eventually lead to accidents. Axial power and axial offset (AO) are key parameters which are usually used to state 3-dimensional core power peaking, in the form of a practical parameter. Group method of data handling (GMDH) has a wide range of applications. Here, a GMDH is used and modified as an efficient method to predict the axial power and AO of the reactor core as well as fuel assemblies. In this paper, axial power offset of the whole reactor core is reconstructed by using in-core detectors. By using the developed GMDH algorithm, the optimum relationship between the independent in-core detector signals and the dependent variables, the core axial power and AO, is determined. Two separate sets of big data are prepared and analyzed. The first set includes power at each of 24 axial nodes at different core states. The second set is similar to the first set except as it also contains fuel assembly data.

This work investigates the depletion capability implemented in lattice physics code STREAM for the prediction of pressurized water reactor (PWR) uranium dioxide (UO2) spent nuclear fuel (SNF) isotopic inventory. The validation of this capability is performed by comparison of STREAM calculation results to measured SNF assay data obtained from PWRs Takahama-3, Calvert Cliffs and GKN II. The depletion analysis is conducted with the ENDF/B-VII.0 library and uses a pin cell model of the fuel rods from which the fuel samples were taken. The Chebyshev Rational Approximation Method (CRAM) is used to solve the depletion equation with about 1300–1600 isotopes in the depletion chain. 16 actinides and 23 fission products are analyzed in 14 spent UO2 fuel samples. The actinides are isotopes of uranium, neptunium, plutonium, americium and curium. The fission products nuclides include isotopes of cesium, neodymium, europium, samarium as well as 106Ru, 144Ce, 155Gd, 99Tc, 90Sr, 109Ag, and 103Rh. The sensitivity of some of the nuclides to the details of the power history and the adjustment of the fuel sample burnup is discussed. The impact of using ENDF/B-VII.0 library instead of ENDF/B-VI.8 is also discussed. Most of the nuclides analyzed are well predicted within ±7% of the experiment for actinides and fission products. STREAM depletion results are also compared to the codes SWAT, HELIOS and SCALE results based on publicly available information in literature, to check the performance of STREAM relative to other codes for the prediction of SNF isotopic inventory. The comparison to other code systems shows that the implementation in STREAM is of comparable accuracy. Overall, this paper demonstrates that the depletion capability in STREAM can be reliably applied to predict the isotopic inventory of PWR UO2 SNF for burnup ranging from 14 to 54 GWd/t and initial enrichment ranging from 3.0 to 4.1 wt% 235U.

This study presents the first application of the advanced Rossi-alpha method (theoretically introduced by Kong et al., 2014) on the reactivity measurements in a research reactor: detector count signals at the Kyoto University Critical Assembly (KUCA) facility. The detector signals in the KUCA A-type core are analyzed by three subcriticality measurement methods: (1) Feynman-alpha (F-α) method, (2) Rossi-alpha (R-α) method, and (3) advanced Rossi-alpha (advanced R-α) method. Four cases are analyzed for two different subcritical states of the core and two different neutron source locations. Two different negative reactivity ρ values are obtained by the measurements of control rod worth and regarded as the reference reactivity values, comparing the results by the four methods. The F-α shows reactivity errors ranging between 7.1 and 7.3% due to its use of variance-to-mean ratios of detector count signals, which are not very sensitive to neutron background noise. However, the fitting uncertainties associated to the F-α results are large, ranging between 5.4 and 12.8% at one standard deviation. The R-α shows small fitting uncertainties ranging between 2.8 and 3.8%, although reactivity errors are in the range of 3.5–26.5% due to the neutron background noise. Finally, the advanced R-α that explicitly models the neutron background noise contrary to the previous methods shows the reactivity errors in the range of 1.0–11.8%, and provides the lowest uncertainties of the measured ρ in the range of 0.4–0.9%. In conclusion, among the four methods applied to the reactivity measurements at KUCA, the advanced R-α reveals the best accuracy with the lowest uncertainties.

Vanadium, rhodium, silver and cobalt Self-Powered Neutron Detectors (SPNDs) are evaluated and compared in this study, including their characteristic response time. The module for response calculations of different SPNDs has been programmed and added to RAST-K v2.0 (Reactor Analysis code for Steady-state and Transient). For simplification purposes and running time minimization, previously studies have often adopted the simplified depletion chain of the SPNDs. The isomers are often neglected in the detectors studies because of their low levels of contribution to the final signal. Besides, few published documents can be found for comparisons of the behavior of different emitters in normal power changes, especially for silver and cobalt emitters. In this paper, the full depletion chains for different emitters are adopted, and the isomers’ contributions are calculated. A new method for detector response calculation based on Chebyshev Rational Approximation Method (CRAM) is used as the depletion method. It is shown that the response of silver SPND is very similar to that of rhodium SPND and can be considered as an alternate emitter material for light water reactors. This study can contribute to the selection of proper SPNDs in specific applications.

Summary In this paper, new in-core self-powered neutron detector emitter candidate materials, ie, vanadium, cobalt, and silver, have been examined in their lifetimes compared with the commonly used rhodium emitter. Using a new quantitative lifetime evaluation model, the lifetimes of vanadium and cobalt were determined to be longer than that of rhodium, but these materials were also shown to have the disadvantage of low signal intensities. Under normal operating conditions, we showed that rhodium emitter can be used for 2 cycles of pressurized water reactors (PWRs) with lifetime of 4.35 years, whereas silver can be used for 5 cycles of PWRs with lifetime of 8.04 years. Three sensitivity tests were performed for rhodium and silver about (1) the emitter size, (2) the fuel assembly burnup, and (3) the emitter temperature variations. From the test results, we observed that the lifetimes of rhodium and silver emitters remained 2 and 5 cycles long, respectively. We concluded that silver can significantly extend the in-core detector's lifetime in PWR operation.

Although Asian people are believed to be more susceptible to bleeding on currently recommended dose of ticagrelor, there is limited evidence supporting low-dose ticagrelor. We prospectively randomized patients receiving dual antiplatelet therapy with aspirin and clopidogrel into 3 groups; aspirin plus clopidogrel 75 mg versus aspirin plus ticagrelor 90 mg once daily versus aspirin plus ticagrelor 45 mg twice daily. Platelet function assessments were conducted using VerifyNow P2Y12 assay at baseline and 28 days after randomization. No differences in baseline P2Y12 reaction unit (PRU) values were observed among the 3 groups. PRU values at the end of the treatment periods were significantly lower in low-dose ticagrelor (90 mg QD group, 98.6 ± 73.4 and 45 mg BID group, 65.5 ± 58.8) compared with clopidogrel (221.2 ± 50.1, both p

The ex-core detector response calculation is an important part in reactor design. However, the response function cannot be measured by experiments quantitatively. Ex-core detector response simulation is therefore required. For decades, the S N code has been used as the dedicated tool. Nowadays, more and more engineers are expressing an interest in using the Monte-Carlo method instead of the S N method in simulations, as it is expected that the Monte-Carlo method will give higher accuracy. In this paper, the modeling and simulation of ex-core detector responses is briefly reviewed based on the Korean Kori Unit 1 reactor. Then, the differences between the S N simulation and Monte-Carlo simulation are compared. The sensitivity of computational conditions is also discussed. It is shown that the problem dependence of cross sections and meshing dependence of spatial discretization in the ex-core detector response calculations are not as strong as expected. However, the ray effect is the main shortcoming for the S N calculation. Based on the analysis, two benefits are shown by using MCNP for the direct 3D calculation. Firstly, the impact of ray effect is eliminated without using the S N angular discretization. Secondly, the direct 3D calculation is easier to perform based on the powerful ability of 3D modeling and parallel computing of the Monte-Carlo code. The new DRF values are adopted in the dynamic control rod reactivity measurement of Kori Unit 1 reactor. The results show that the new DRF values improve the error of measured control rod worth by a percentage of 3.

This study presents a coolant void reactivity analysis of Canada Deuterium Uranium (CANDU)-6 and Advanced Canada Deuterium Uranium Reactor-700 (ACR-700) fuel lattices using a Monte Carlo code. The reactivity changes when the coolant was voided were assessed in terms of the contributions of four factors and spectrum shifts. In the case of single bundle coolant voiding, the contribution of each of the four factors in the ACR-700 lattice is large in magnitude with opposite signs, and their summation becomes a negative reactivity effect in contrast to that of the CANDU-6 lattice. Unlike the coolant voiding in a single fuel bundle, the 2 × 2 checkerboard coolant voiding in the ACR-700 lattice shows a positive reactivity effect. The neutron current between the no-void and voided bundles, and the four factors of each bundle were analyzed to figure out the mechanism of the positive coolant void reactivity of the checkerboard voiding case. Through a sensitivity study of fuel enrichment, type of burnable absorber, and moderator to fuel volume ratio, a design strategy for the CANDU reactor was suggested in order to achieve a negative coolant void reactivity even for the checkerboard voiding case.

Long-term exposure to particulate matter (PM) air pollution is associated with all-cause mortality and adverse cognitive outcomes, but the association with developing depression remains inconsistent.Our goal was to evaluate the prospective association between PM air pollution and developing depression assessed using the Center for Epidemiological Studies Depression (CES-D) scale.Subjects were drawn from a prospective cohort study of 123,045 men and women free of depressive symptoms at baseline who attended regular screening exams in Seoul and Suwon, South Korea, from 2011 to 2015. Exposure to PM with an aerodynamic diameter of [Formula: see text] ([Formula: see text] and [Formula: see text], respectively) was estimated using a land-use regression model based on each subject's residential postal code. Incident depression was defined as a CES-D score [Formula: see text] during follow-up. As a sensitivity analyses, we defined incident depression using self-reports of doctor's diagnoses or use of antidepressant medications during follow-up.The mean baseline 12-month concentrations of [Formula: see text] and [Formula: see text] were 50.6 (4.5) and [Formula: see text], respectively. The hazard ratios (HRs) and 95% confidence intervals (CIs) for developing depression associated with a [Formula: see text] increase in 12- and 60-month [Formula: see text] exposure were 1.11 (95% CI: 1.06, 1.16) and 1.06 (95% CI: 1.01, 1.11), respectively. The corresponding HRs for 12-month [Formula: see text] exposure was 0.96 (95% CI: 0.64, 1.43). Similar results were obtained when incident depression was identified using self-reports of doctor's diagnoses or the use of antidepressant medications.In this large cohort study, we found a positive association between long-term exposure to outdoor [Formula: see text] air pollution and the developing depression. We did not find an association for outdoor [Formula: see text] air pollution; however, we had a much shorter follow-up for subjects' exposure to [Formula: see text]. https://doi.org/10.1289/EHP4094.

We aimed to determine the association between alcohol consumption change on fasting serum glucose, insulin resistance, and beta cell function. The study population consisted of 55,858 men from the Kangbuk Samsung Health Study. Participants were divided into non-, light, moderate, and heavy drinkers for each of the first and second health examinations based on a self-reported questionnaire on alcohol consumption. The adjusted mean values for change in fasting serum glucose (FSG), homeostatic model assessment of insulin resistance (HOMA-IR), and beta cell function (HOMA-β) levels were determined according to alcohol consumption change by linear regression. Compared to sustained initial drinkers, those who increased alcohol intake to moderate (p 0.001) and heavy (p 0.001) levels had increased FSG levels. In contrast, reduction in alcohol intake to light levels among initial heavy drinkers was associated with reduced change in FSG levels (p = 0.007) compared to sustained heavy drinkers. No significant associations were observed between changes in alcohol intake with HOMA-IR levels. Compared to sustained light drinkers, those who increased alcohol intake to moderate (p 0.001) and heavy (p = 0.009) levels had lower increases in HOMA-β levels. Finally, compared to sustained heavy drinkers, those who reduced alcohol consumption to light levels had greater increases in HOMA-β levels (p = 0.002). Increases in alcohol consumption were associated with higher blood glucose levels and worsened beta cell function. Heavy drinkers who reduce alcohol intake could benefit from improved blood glucose control via improved beta cell function.

The rod ejection accident (REA) is the most severe reactivity-initiated accident of the pressurized water reactors (PWRs). The three-dimensional (3-D) neutron kinetics method is widely applied to the REA analysis, where the fixed neutron source is usually ignored at the hot zero power (HZP) condition. This paper describes a new capability of the 3-D nodal diffusion code, RAST-K to consider the fixed source in the low power transient analysis of the PWR reload core. The RAST-K calculates the fixed source originated from the spontaneous fission and the (α,n) reaction, which is verified by the ORIGEN code. The new capability is applied to the REA analysis at the HZP condition for various initial core power levels and the results are compared with those of ignoring the fixed source. The numerical results show that the fixed source significantly suppresses the power pulse of the REA by imposing the initial negative reactivity.

Background and objectives Intravascular ultrasound (IVUS)-guided percutaneous coronary intervention frequently results in unnecessary stenting due to the low positive predictive value of IVUS-derived minimal lumen area (MLA) for identification of functionally significant coronary stenosis. We appraised the diagnostic accuracy of IVUS-derived MLA compared with the fractional flow reserve (FFR) to assess intermediate coronary stenosis. Subjects and methods We searched MEDLINE and Cochrane databases for studies using IVUS and FFR methods to establish the best MLA cut-off values to predict significant non-left main coronary artery stenosis. Summary estimates were obtained using a random-effects model. Results The 17 studies used in our analysis enrolled 3920 patients with 4267 lesions. The weighted overall mean MLA cut-off value was 2.58 mm2. The pooled MLA sensitivity that predicted functionally significant coronary stenosis was 0.75 (confidence interval [CI]: 0.72 to 0.77) and the specificity was 0.66 (CI: 0.64 to 0.68). The positive likelihood ratio (LR) was 2.33 (CI: 2.06 to 2.63) and LR (-) was 0.33 (CI: 0.26 to 0.42). The pooled diagnostic odds ratio (DOR) was 7.53 (CI: 5.26 to 10.76) and the area under the summary receiver operating characteristic curve for all the trials was 0.782 with a Q point of 0.720. Meta-regression analysis demonstrated that an FFR cut-off point of 0.75 was associated with a four times higher diagnostic accuracy compared to that of 0.80 (relative DOR: 3.92; 95% CI: 1.25 to 12.34). Conclusion IVUS-derived MLA has limited diagnostic accuracy and needs careful interpretation to correlate with functionally significant non-left main coronary artery stenosis.

Summary This paper presents a preliminary design of a Small Modular Pressurized Water Reactor (SMPWR) aimed at boron-free operation which can reduce the size of a nuclear power plant (NPP) and the amount of liquid radioactive waste, and also reduce the corrosion issues caused by boric acid in the coolant. The design parameter limits, such as reactivity swing, axial offset (AO), 3D pin peaking factor (Fq), and the required shutdown margin, have been established for the boron-free SMPWR. Furthermore, a new ring type of burnable absorber (R-BA) with Zr–167Er is adopted as a burnable absorber (BA) and HfB2 is adopted as a control rod material to satisfy those design limits without liquid boron. Optimal fuel assemblies (FAs) and loading patterns have been searched through a sensitivity study, and the excess reactivity control capacity and design requirements have been demonstrated to be satisfactory. Copyright © 2016 John Wiley & Sons, Ltd.

This paper presents an aerial work robot for a nuclear power plant (NPP) with a pressurized heavy water reactor (PHWR). The aerial work robot provides measurements by teleoperating a fuel handling machine placed at a high location in front of the PHWR. The robot can detect a leak from pipes such as delayed neutron (DN) monitoring tubes, which are also placed at a high place. The robot is equipped with radiation-hardened controllers, radiation-hardened cameras, and a noise robust communication system.

This paper presents a new high performance burnable absorber (BA) design for advanced Pressurized Water Reactors (PWRs) aiming for a long-cycle operation with a low soluble boron concentration. The new BA consists of a UO 2 – 157 Gd 2 O 3 rod covered with a thin layer of Zr 167 Er 2 . A key feature of this new BA is that enriched isotopes, 157 Gd and 167 Er, are used as absorber materials. Since the high absorption cross section of 157 Gd can reduce the mass fraction of Gd 2 O 3 in UO 2 –Gd 2 O 3 , the thermal margin of fuel rods will increase with higher heat conductivity. Also, the 157 Gd transmutes into 158 Gd by neutron absorption and therefore the residual penalty at the end of cycle (EOC) will decrease. Since 167 Er has a resonance near the thermal neutron energy region, the moderator temperature coefficient (MTC) will become more negative and the control rod worth will increase. These advantages of the new BA are demonstrated with three verification cases: a 17 × 17 Westinghouse (WH) type fuel assembly, a 16 × 16 Combustion Engineering (CE) type fuel assembly, and an OPR-1000 equilibrium core.

Chronic fatigue (CF) is a common reason for consulting a physician due to affecting quality of life, but only a few effective treatments are available. The aim of this study was to examine the effectiveness of subcutaneous injection of the human placental extract (HPE) on medically indescribable cases of CF and safety in a randomized, double-blind, placebo-controlled clinical trial. A total of 78 subjects with CF were randomly assigned to either a HPE group or a placebo group. Subjects in the HPE group were treated with HPE three times a week subcutaneously for 6 weeks, whereas those in the placebo group with normal saline. Then, the fatigue severity scale (FSS), visual analog scale (VAS) and multidimensional fatigue inventory (MFI) were measured in both CF group and chronic fatigue syndrome (CFS) and idiopathic chronic fatigue (ICF) subgroup. The FSS, VAS and MFI score at baseline were not different between the HPE and placebo group in total subjects with CF. In CFS group, the FSS (p=0.0242), VAS (p=0.0009) and MFI (p=0.0159) scores measured at the end of the study period decreased more in the HPE group than in the placebo group when compared with those at the baseline. There were no significant differences between the HPE group and placebo group in the mean change from baseline in FSS, VAS, and MFI in subjects with ICF during the study period. The subcutaneous injection of HPE was effective in the improvement of CFS.

Accurate prediction of supersonic transition is required for the heat transfer estimation over supersonic double compression ramp flows. Correlation-based transition models were assessed for a supersonic double ramp problem. Numerical results were compared with experimental data from RWTH Aachen University. A parametric study on the nose bluntness was performed using a selected transition model. As the nose bluntness increases, the boundary layer thickness is increased and the triple point of shock interactions moves downstream. The peak magnitude of the heat transfer is consequently decreased with the nose bluntness.

Objective: Long-term exposure to fine particulate matter less than 2.5 µm in diameter (PM2.5) and less than 10 µm in diameter (PM10) are associated with cardiovascular risk. The mechanisms underlyi...

This paper describes the design of a remote control robot system for hazardous environments such as a severe accident or the dismantling of a nuclear power plant. Occasionally, it is necessary for a robot to carry out the cutting work. We designed the hardware of a robot system and the software architecture. The system to be developed is composed of a master device, a slave robot, and a mobile platform, as well as a telescopic mast that moves the slave robot to the desired position. The integrating program has a system component control module, a virtual guide implementing module, and egocentric remote control algorithms. In addition, we developed a cutting tool for the robot system and carried out a cutting test of a 2 inch steel pipe with 5 mm thickness.

Summary This paper presents detailed analyses of a pressurized water reactor with a new reflector design using zirconium metal. The optimization of the reflector design has been performed using a two-dimensional fuel assembly reflector model. The three-dimensional core calculation results with the optimized reflector were compared against those with the existing water reflector and iron reflector. The high scattering cross section of zirconium enhances neutron reflections from the reflector to the core, increasing the peripheral assembly powers. From the analysis based on the equilibrium core, it was noted that the cycle length can be extended, and the pin peaks can be decreased when using zirconium reflector. The analysis has been performed for the optimized power reactor 1000 core with combustion engineering type fuel assemblies using the CASMO-4E/SIMULATE-3 (Studsvik Scandpower, Inc., Waltham, MA, USA) code system and SERPENT (VTT Technical Research Centre of Finland, Vuorimiehentie 3, 02150 Espoo, Finland) code, with ENDF/B-VI data. Copyright © 2015 John Wiley & Sons, Ltd.

Aims There have been several studies on the association between metabolic syndrome (MetS) and microalbuminuria. However, none has examined whether MetS is associated with the prospective development of microalbuminuria. Accordingly, we performed a prospective study to evaluate the longitudinal effects of baseline number of MetS traits on the development of microalbuminuria in Korean men. Methods 1649 Korean men without microalbuminuria in 2005 were included and followed prospectively until 2010 with the endpoint being the development of microalbuminuria. MetS was defined according to the joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention. Microalbuminuria was evaluated by urine albumin creatinine ratio (UACR). Risk estimations for development of microalbuminuria were analyzed according to the number of MetS traits using multivariate adjusted Cox proportional hazards model. Results During 5611.8 person-years of follow-up (median 3.40 ± 1.46 years), microalbuminuria developed in 91 (5.5%) participants between 2006 and 2010. After adjusting for multiple covariates, the hazard ratios (95% confidence interval) for development of microalbuminuria comparing 1, 2 and 3–5 MetS traits vs 0 were 2.57 (0.97–6.82), 2.94 (1.09–7.98) and 3.85 (1.37–10.86), respectively. Conclusions The number of MetS traits independently associated with the future development of microalbuminuria during the 5-year follow-up period, and MetS per se was an independent risk factor for microalbuminuria.

Background Although previous studies have suggested clinical benefits of complete revascularization in patients with multivessel coronary artery disease, it is still controversial whether preventive percutaneous coronary intervention (PCI) leads to better clinical outcomes in the clinical setting of ST-segment elevation myocardial infarction (STEMI). Methods Relevant studies through September 2014 were searched and identified in the electronic databases. Primary endpoint was all-cause mortality at the longest follow-up. Secondary endpoints included myocardial infarction (MI), repeat revascularization, and major adverse cardiac events (MACE). Results From 836 initial citations, 7 randomized trials, and 23 observational studies with 44,256 patients (8,087 preventive and 36,169 culprit-only) were included in this study. Preventive PCI was associated with a significant reduction in repeat revascularization (odds ratios [OR]: 0.71; 95% CI: 0.51–0.99) with no differences in all-cause mortality (OR: 0.99; 95% CI: 0.76–1.29) or MI (OR: 1.08; 95% CI: 0.62–1.87) as compared with culprit-only PCI. Comparison of preventive PCI to the culprit-only PCI group revealed OR for MACE of 0.80 (95% CI: 0.57–1.12). Stratified analysis according to revascularization strategy demonstrated a significant survival benefit of culprit-only PCI over multivessel PCI during the index procedure and a significantly lower incidence of all-cause mortality with staged PCI as compared with culprit-only or multivessel PCI during the index procedure. Conclusions Preventive PCI strategy appears to be effective in reducing the risk of repeat revascularization without significant benefits for mortality or MI when compared with culprit-only revascularization in STEMI patients with multivessel disease. (J Interven Cardiol 2015;28:1–13)

Isolated left ventricular noncompaction (LVNC) is a rare cardiomyopathy with morphologic characteristics of two distinct myocardial layers i.e., thin compacted epicardial and thick noncompacted endocardial layers. The noncompacted myocardium consists of prominent ventricular trabeculae and deep intertrabecular recesses. It can lead to arrhythmias, heart failure or systemic embolisms. Electrocardiographic patterns of patients with LVNC are various and non-specific; however, the most common findings are intraventricular conduction delay, left ventricular hypertrophy, and repolarization abnormalities. We reported the first case, to the best of our knowledge, of a 29-year-old man who had recent cerebral infarction and incidental LVNC with spontaneous left atrial standstill.

This paper proposes a new control rod material for a boron-free small modular pressurized water reactor (SMPWR) to compensate the loss of the soluble boron. To design control rod for SMPWR is difficult due to the large amount of reactivity control necessity and the multiple roles of control rod, i.e., the excess reactivity control, the coarse/fine power control, and the axial shape control and shutdown. This paper presents a study of various control rod materials: B4C, Ag-In-Cd, and HfB2. The rod worth and the excess reactivity control capability will be assessed for the SMPWR using Studsvik’s reactor core design code system, CASMO-4E/SIMULATE-3.

Background and Aim: Non-alcoholic fatty liver disease (NAFLD) is getting an increas- ing attention for its clinical implications on cardiovascular disease (CVD). However, epidemiologic data are not so evident to sustain the causative association between NAFLD and hypertension, the major cause of CVD. Accordingly, we designed this study to investigate the clinical association between NAFLD and the development of hypertension. Methods: To assess the natural course of blood pressure according to degree of NAFLD (normal, mild, and moderate to severe), we conducted a prospective cohort study on the 22 090 Korean men without hypertension for 5 years. We serially checked the various metabolic factors including systolic and diastolic blood pressure in order to monitor the development of hypertension. Results: The incidence rate of hypertension increased according to the degree of NAFLD (normal: 14.4%, mild: 21.8%, moderate to severe: 30.1%, P < 0.001). Even after adjusting for other multiple covariates, the hazard ratios (95% confidence intervals) for hypertension were higher in the mild group (1.07; 1.00-1.15) and moderate to severe group (1.14; 1.00-1.30), compared with normal group, respectively (P for trend < 0.001). Conclusion: Development of hypertension is more potentially associated with the more progressive NAFLD than normal or milder state. In addition, NAFLD was an independent risk factor for hypertension.

This paper describes the Group Method of Data Handling (GMDH) algorithm to reconstruct 20-node axial core power shapes from five-level in-core detector power measurements. Conventional methods in this field are the parameter identification framework by adopting fixed basis functions and the determination of parameters weighted to each terms of known functions like Fourier series or spline forms. This study proposes GMDH, an evolutionary algorithm, to find the optimal functional form and parameters simultaneously those describe the power distribution accurately. A total of 1060 cases of axially 1-dimensional core power distributions of 20-nodes are generated by 3-dimensional core design code covering beginning-of-life to end-of-life core burnup histories to validate the method. Axially five-point box powers at in-core detector positions are considered as measured snapshots. The reconstructed axial power shapes using GMDH method are compared to the reference power shapes. The results show that the proposed method is very robust and accurate compared with the spline fitting method.