• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1174-1183
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• 2016

Hydrogen release during severe accidents poses a serious threat to containment integrity. Mitigating procedures are necessary to prevent global or local explosions, especially in large steel shell containments. The management of hydrogen safety and prevention of over-pressurization could be implemented through a hydrogen reduction system and spray system. During the course of the hypothetical large break loss-of-coolant accident in a nuclear power plant, hydrogen is generated by a reaction between steam and the fuel-cladding inside the reactor pressure vessel and also core concrete interaction after ejection of melt into the cavity. The MELCOR 1.8.6 was used to assess core degradation and containment behavior during the large break loss-of-coolant accident without the actuation of the safety injection system except for accumulators in Beznau nuclear power plant. Also, hydrogen distribution in containment and performance of hydrogen reduction system were investigated.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.4
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• pp.312-319
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• 2014

When distributed generation such as a wind power system is connected to the grid, it should meet grid requirements like IEEE Std. 1547, which regulates the anti-islanding method. Since the islanding may cause damage on electrical equipments or safety hazards for utility line worker, a distributed generation should detect it as soon as possible. This paper proposes a hybrid anti-islanding method coupled with the active and passive detection methods. To enhance the harmonic extraction capability for an active harmonic injection method, cascaded second-order band-pass filter and signal processing scheme are employed. Simulation and experiments are carried out under the islanding test condition specified in IEEE Std. 1547. Passive over/under voltage and over/under frequency methods are combined with the active method to improve the detection speed under certain condition. The simulation and experimental results are presented to verify that the proposed hybrid anti-islanding method can effectively detect the islanding.

• Clinical and Experimental Vaccine Research
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• v.11 no.1
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• pp.104-115
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• 2022

Purpose: In the United States, Pfizer-BioNTech, Moderna, and Janssen's coronavirus disease 2019 (COVID-19) vaccines have been granted Emergency Use Authorization (EUA) with the Pfizer-BioNTech vaccine presently approved by the US Food and Drug Administration. The purpose of this study is to analyze passive surveillance data on COVID-19 vaccine adverse reaction in the United States. Materials and Methods: We analyzed passive surveillance data on COVID-19 vaccine adverse reactions which were retrieved from the Vaccine Adverse Event Reporting System database. Retrieved records on demographic information as well as the top 10 common vaccine adverse events were extracted and assessed from 200 of the most recently reported cases for the study analysis. Results: Local and systemic adverse reactions were reported in the study. A significant difference (p<0.05) was recorded for the top 10 systemic reactions by age category (0.041) and by gender (0.002). Analysis of the top five systemic reactions, stratified by vaccine type yielded a significant difference (p<0.05) for chills (p=0.044), and when stratified by age group and type of vaccination received, it yielded a significant difference (p<0.05) for fatigue (p=0.023). Overall, Pfizer had 182 persons (91.0%) reporting adverse events, Moderna with 13 (6.5%), and Janssen with 5 (2.5%). Conclusion: Mild side effects were reported following vaccination with the EUA COVID-19 vaccines in the United States. Thus, continuous monitoring and reporting of all adverse events are recommended to ensure the safety of vaccination.