• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3639-3647
• /
• 2023

This paper defines a 3D full core neutronics benchmark which is based on the NuScale small modular reactor (SMR) concept. The paper provides a detailed description of the NuScale-like core, a list of expected outputs, and a reference solution to the benchmark exercises obtained with the Monte Carlo code Serpent. The benchmark was developed in the framework of the Euratom McSAFER project and can be used for verification of computational chains dedicated to 3D full-core neutronics simulations of water cooled SMRs. The paper is supplemented with a digital data set to ease the modeling process.

• Korean Journal of Adult Nursing
• /
• v.25 no.6
• /
• pp.655-664
• /
• 2013

Purpose: This study was undertaken to identify which delirium screening instrument would be more useful in clinical practice. Methods: Data were collected from 118 nurses from six hospitals in five provinces in Korea. For the delirium screening three instruments were compared: NEECHAM Confusion Scale (NEECHAM), Nursing Delirium Screening Scale (Nu-DESC), Delirium Observation Scale (DOS). The MMSE-K was used for concurrent validity. The nurse subjects were surveyed as to the practical clinical value of each instrument. Cronbach's ${\alpha}$ coefficient and Kuder-Richardson 20 were used to confirm the reliability. Results: The range of three scales reliability was .70~.82 and the range of correlation coefficient was .63~.82 with MMSE-K. For sensitivity of NEECHAM, Nu-DESC and DOS was 1.00, 1.00 and 0.81 respectively and specificity NEECHAM, Nu-DESC and DOS was 0.88, 0.89 and 0.89 respectively. Nurses rated the practical use of the DOS scale as significantly easier to use than the NEECHAM and Nu-DESC. Conclusion: NEECHAM, Nu-DESC and DOS scales were acceptable in terms of reliability, validity, sensitivity and specificity. However, nurses rated the DOS scale as easier scale to use and had more relevance to their practice.

• Journal of Korean Academy of Nursing
• /
• v.42 no.3
• /
• pp.414-423
• /
• 2012

Purpose: The aims of this study were to develop and test the validity of the Korean Nursing Delirium Scale (Nu-DESC) for older patients in hospital. Methods: The Korean Nu-DESC was developed based on the Nu-DESC (Gaudreau, 2005), and revised according to nursing records related to signs and symptoms of older patients with delirium (n=361) and the results of a pilot study (n=42) in one general hospital. To test the validity of the Korean Nu-DESC, 75 older patients whom nurses suspected of delirium from 731 older patients from 12 nursing units were assessed by bedside nurses using the Korean Nu-DESC. A Receiver Operating Characteristic Curve of the Korean Nu-DESC was constructed with an accompanying Area Under the Curve (AUC). Results: Specific examples such as irritable, kidding, sleeping tendency, which were observed by bedside nurses in Korea, were identified in the five features of signs and symptoms of delirium in the instrument. The Korean Nu-DESC was psycho-metrically valid and had a sensitivity and specificity of .81-.76 and .97-.73, respectively. The AUC were .89, .74. Conclusion: Results of this study indicate that the Korean Nu-DESC is well-suited for widespread clinical use in busy inpatients settings and shows promise as a research instrument.

• Nuclear Engineering and Technology
• /
• v.54 no.12
• /
• pp.4499-4513
• /
• 2022

Spent fuel behavior of dry storage was simulated in a continuous state from steady-state operation by modifying FRAPCON-4.0 to incorporate spent fuel-specific fuel behavior models. Spent fuel behavior of a typical PWR was compared with that of NuScale Power Module (NPM^TM). Current PWR discharge burnup (60 MWd/kgU) gives a sufficient margin to the hoop stress limit of 90 MPa. Most hydrogen precipitation occurs in the first 50 years of dry storage, thereby no extra phenomenological safety factor is identified for extended dry storage up to 100 years. Regulation for spent fuel management can be significantly alleviated for LWR-based SMRs. Hydride embrittlement safety criterion is irrelevant to NuScale spent fuels; they have sufficiently lower plenum pressure and hydrogen contents compared to those of PWRs. Cladding creep out during dry storage reduces the subchannel area with burnup. The most deformed cladding outer diameter after 100 years of dry storage is found to be 9.64 mm for discharge burnup of 70 MWd/kgU. It may deteriorate heat transfer of dry storage by increasing flow resistance and decreasing the view factor of radiative heat transfer. Self-regulated by decreasing rod internal pressure with opening gap, cladding creep out closely reaches the saturated point after ~50 years of dry storage.

• Wind and Structures
• /
• v.28 no.1
• /
• pp.63-70
• /
• 2019

Due to developing environmental concern use of renewable energy source is very essential. The great demand for the energy supply coupled with inadequate energy sources creates an emergency to find a new solution for the energy shortage. The appropriate wind energy distribution is the fundamental requirement for the assessment of wind energy potential available at the particular site essential for the design of wind farms. Hence the proper specification of the wind speed distribution plays a vital role. In this paper the Bimodal Weibull distribution is used to estimate the Capacity factor at the proposed site. The shape and scale parameters estimated using Maximum likelihood method is used as the initial value for extrapolation. Application of this model will give an accurate result overwhelming the concept of overestimation or underestimation of Capacity factor.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.1
• /
• pp.24-30
• /
• 2004

Analysis model for the two-phase catalytic reactor is presented. With the progress in development of micro thermofluidic devices, needs fur understanding of the phenomena in two phase reaction in cm scale has been arisen. To investigate thermal and reactive performance of down scaled two phase reactor simple analysis model that is a kind of lumped flow model is proposed. Analysis model presented is based on the experiment on mm scale model reactor. Target experiment is catalytic decomposition of 70wt％ hydrogen peroxide with existence of perovskite L $a_{0.8}$S $r_{0.2}$Co $O_3$ catalyst. It is composed of balance equations of mass and energy. Each phase is considered to be a species fur the simplicity. Axial diffusion and transversal distribution of properties are neglected. Two phase catalytic reaction is modeled as successive gasification of liquid lump around catalyst and reaction in gas phase. Heat transfer is modeled by model function ofNu number. Modeled Nu is expressed as Nu=N $u_{0}$ (1＋ $a_1$( $a_2$ $T^{-}$ $a_3$)exp( $a_4$ $T^{-1}$)exp( $a_{5}$ z). Transfer coefficients are determined by the comparison of experimental results. With the model, heat transfer characteristics are investigated. Also by the mass transfer coefficient, characteristics in mass transfer is investigated. With the result basic understanding on design and analysis of mm scale two-phase reactive device is obtained. Also it can be further applied to micro scale reactive device fabricated by micromachining.ing..

• Journal of the Korean Statistical Society
• /
• v.35 no.4
• /
• pp.419-439
• /
• 2006

The article develops a new class of distributions by introducing a nonnegative perturbing function to $t_\nu$ distribution having location and scale parameters. The class is obtained by using transformations and conditioning. The class strictly includes $t_\nu$ and $skew-t_\nu$ distributions. It provides yet other models useful for selection modeling and robustness analysis. Analytic forms of the densities are obtained and distributional properties are studied. These developments are followed by an easy method for estimating the distribution by using Markov chain Monte Carlo. It is shown that the method is straightforward to specify distribution ally and to implement computationally, with output readily adopted for constructing required criterion. The method is illustrated by using a simulation study.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.5
• /
• pp.1138-1149
• /
• 1988

Experiments have been conducted to investigate mean thermal structure in unstable turbulent thermal convection between two horizontal flat plates. The upper plate was kept at a constant cold temperature and the bottom plate at a constant hot temperature. Both air and water were used as its working fluids. Chamber aspect ratios were 3.80 and 6.17, the mean temperature differences between two plates were 2.6-9.3.deg. C, whose Rayleigh numbers in a range 6.13*10$^{5}$ -1, 07*10$^{8}$ . The heat transfer correlations obtained through the experiments are Nu=0.139R $a^{0.285}$ for air and Nu=0.087 R $a^{0.319}$ for water. Profiles of the mean temperature gradient clearly show the -2 and 1 4/3 power law regions.

• Journal of Oriental Neuropsychiatry
• /
• v.33 no.3
• /
• pp.339-349
• /
• 2022

Objectives: The purpose of this study was to report the effectiveness of the combination of Giungoroen-therapy, as well as other Korean medicine therapy on postoperative delirium. Methods: The patient was diagnosed with postoperative delirium, that occurred after arthroscopic debridement two months before hospitalization. The patient received Giungoroen-therapy in addition to conventional Korean Medicine treatment, including acupuncture, herbal medicine, and moxibustion. The evaluation variables to check the effectiveness of the interventions, were the Korean Nursing Delirium Screening Scale (Korean Nu-DESC) and the Korean Version of the Delirium Rating Scale-Revised-98 (K-DRS-R-98). Results: During the hospitalization period, the Korean Nu-DESC score decreased from 5 to 1, and the K-DRS-R-98 score decreased from 36 to 23. The subjective expression of anxiety had been reduced. Conclusions: The combination of Giungoroen-therapy, as well as other Korean medicine therapy including acupuncture, moxibustion, and herbal medicine may be useful in alleviating postoperative delirium.

• Nuclear Engineering and Technology
• /
• v.55 no.1
• /
• pp.330-338
• /
• 2023

In this study, impacts of an enhanced-moderation Fuel Assembly (FA) named Truly Optimized PWR (TOP) lattice, which is modified based on the standard 17 × 17 PWR FA, are investigated in a natural circulation Soluble-Boron-Free (SBF) Small Modular Reactor (SMR). Two different TOP lattice designs are considered for the analysis; one is with 1.26 cm pin pitch and 0.38 cm fuel pellet radius, and the other is with 1.40 cm pin pitch and 0.41 cm fuel pellet radius. The NuScale core design is utilized as the base model and assumed to be successfully converted to an SBF core. The analysis is performed following the primary coolant circulation loop, and the reactor is modelled as a single channel for thermal-hydraulic analyses. It is assumed that the ratio of the core pressure drop to the total system pressure drop is around 0.3. The results showed that the reactor power could be increased by 2.5% and 9.8% utilizing 1.26/0.38 cm and 1.40/0.41 cm TOP designs, respectively, under the identical coolant inlet and outlet temperatures as the constraints.