• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.862-868
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• 1998

Korean Next Generation Reactor(KNGR) is a standardized evolutionary Advanced Light Water Reactor design under development Korea Power Company(KEPCO). It incorporates design enhncements such as active and passive advanced design features(ADFs) to increase the plant safety. A Preliminary level 1 Probabilistic Safety Assessment(PSA) has been performed for KNGR to examine the effect of these safety features. The preliminary PSA result shows that it meets the KNGR safety goal on core damage frequency(CDF). The result of this safety assessment shows that the four-train safety systems, and the ADFs such as Passive Secondary Cooling System (PSCS) contributes greatly to the reduction the CDF. Furthermore, several design changes are made or proposed for detailed review based on the PSA insights.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.134-139
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• 2009

Various modules are generally combined with one another in order to perform rotorcraft preliminary design and its optimization. At the stage of the preliminary design, analysis fidelity is less important than the rapid assessment of a design is. Most of the previous researchers attempted to implement sophisticated applications in order to increase the fidelity of analysis, but the present paper focuses on a rapid assessment while keeping the similar level of fidelity. Each small-sized module will be controlled by an externally-operated global optimization module. Results from each module are automatically handled from one discipline to another which reduces the amount of computational effort and time greatly when compared with manual execution. Automatically handled process decreases computational cycle and time by factor of approximately two. Previous researchers and the rotorcraft industries developed their own integrated analysis for rotorcraft design task, such as HESCOMP, VASCOMP, and RWSIZE. When a specific mission profile is given to these programs, those will estimate the aircraft size, performance, rotor performance, component weight, and other aspects. Such results can become good sources for the supplemental analysis in terms of stability, handling qualities, and cost. If the results do not satisfy the stability criteria or other constraints, additional sizing processes may be used to re-evaluate rotorcraft size based on the result from stability analysis. Trade-off study can be conducted by connecting disciplines, and it is an important advantage in a preliminary design study. In this paper among the existing rotorcraft design programs, an adequate program is selected for a baseline of the design framework, and modularization strategy will be applied and further improvements for each module be pursued.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.102-110
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• 2019

This paper describes the work and results of the preliminary Probabilistic Safety Assessment (PSA) for a research reactor in the design phase. This preliminary PSA was undertaken to assess the level of safety for the design of a research reactor and to evaluate whether it is probabilistically safe to operate and reliable to use. The scope of the PSA described here is a Level 1 PSA which addresses the risks associated with core damage. After reviewing the documents and its conceptual design, eight typical initiating events are selected regarding internal events during the normal operation of the reactor. Simple fault tree models for the PSA are developed instead of the detailed model at this conceptual design stage. A total of 32 core damage accident sequences for an internal event analysis were identified and quantified using the AIMS-PSA. LOCA-I has a dominant contribution to the total CDF by a single initiating event. The CDF from the internal events of a research reactor is estimated to be 7.38E-07/year. The CDF for the representative initiating events is less than 1.0E-6/year even though conservative assumptions are used in reliability data. The conceptual design of the research reactor is designed to be sufficiently safe from the viewpoint of safety.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.2
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• pp.221-228
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• 2008

This paper describes to determine optimum main particulars of warships which satisfy user's requirements in a concept design stage with minimum construction cost and maximum transportation efficiency. Present worth was used as an assessment criteria of the economical efficiency. And Pareto optimal set was used to have the optimum design.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.380-386
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• 2017

Fennovoima's nuclear power plant, Hanhikivi 1, $Pyh{\ddot{a}}joki$, Finland, is currently in design phase, and its construction is scheduled to begin in 2018 and electricity production in 2024. The objective of this paper is to produce a preliminary list of safety-significant external event combinations including preliminary probability estimates, to be used in the probabilistic risk assessment of Hanhikivi 1 plant. Starting from the list of relevant single events, the relevant event combinations are identified based on seasonal variation, preconditions related to different events, and dependencies (fundamental and cascade type) between events. Using this method yields 30 relevant event combinations of two events for the Hanhikivi site. The preliminary probability of each combination is evaluated, and event combinations with extremely low probability are excluded from further analysis. Event combinations of three or more events are identified by adding possible events to the remaining combinations of two events. Finally, 10 relevant combinations of two events and three relevant combinations of three events remain. The results shall be considered preliminary and will be updated after evaluating more detailed effects of different events on plant safety.

• Journal of Aerospace System Engineering
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• v.2 no.2
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• pp.14-19
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• 2008

This paper presents the procedure and the results of the preliminary design of the fuel tank as a part of developing the helicopter. For the requirements of operational capability, MIL-DTL-27422D and Defence Standard 15-2/Issue 1 are considered to be applied in developing a helicopter fuel tank. The procedure of the fuel tank development is set up including interface plate design, tank design, former design, tank material lay-up, and tank installation assessment. The outer moulded line and fittings of fuel tank have being designed, and several test will be performed to get the qualification.

• Journal of the Korean Society of Systems Engineering
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• v.6 no.1
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• pp.1-13
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• 2010

KC-100 is a 4 seats, single piston engine, civil aircraft whose type certificate is applied for KAS 23 (FAR 23) for the first time in Korea. Its system safety assessment and analysis have been conducted to meet the minimum safety requirement in KAS 23 and to verify the safety of equipment, system, and installation in accordance with the requirement of ${\S}$23.1309 and the guidelines in FAA AC 23.1309-1D and SAE ARP 4761. This safety assessment begins with the FHA (Functional Hazard Assessment) at aircraft and system level in preliminary design phase, and all of the safety assessment and analysis reports including the preliminary version of SSA (System Safety Assessment) have been prepared during detail design phase. The revised version of these safety reports will be approved by Airworthiness Authority through the ground and flight test phases. In this paper, the safety assessment requirement in ${\S}$23.1309, safety assessment guideline in AC 23.1309-1D, and safety assessment and analysis methods in ARP 4761 will be explained based on the application example for KC-100 development. The experience and knowledge of this system safety assessment for civil aircraft can be applied to commuter aircraft of FAR 23 class or large transport airplane of FAR 25 class.

• Youth Facilities and Environment
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• v.17 no.1
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• pp.131-141
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• 2019

The purpose of this study is to derive and type utilization indexes by comparing public design indicators with preceding studies related to closed school facilities, and to derive preliminary classification systems through a correlation review between indicators. Pre-research was conducted in the scope of academic papers, academic journals, research reports, and special act for promoting the utilization of closed school assets. Public design indicators were set in the scope of domestic design guidelines, the Seoul city public design assessment system, the 'Good Building' designation system, and the UK Design Quality Index (DQI). and the design review of the British architects. First of all, the research method looked at laws, procedures and utilization of closed schools, and reviewed the preceding study and domestic and international public design indicators sequentially. Next, the association was reviewed through a comparison between the preceding study and the public design indicators, and a preliminary classification system for the use of closed schools was derived from this.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.380-389
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• 2011

Esthetic appeal of a product is often affected by the appearance quality of seams forming between components of the product. The appearance quality of seams is, however, assessed in a very subjective and qualitative manner that heavily depends on the evaluator. This paper presents a preliminary study to quantify such assessment by formulating a quantitative index which is a linear function of the seam gap sizes, seam gap ranges, and the size uniformity of seam gaps. By considering a highly simplified problem of a drawer system and utilizing subjective assessments by twenty evaluators, the index has been formulated. The validity of this index has been confirmed by observing its behavior with changes of the component tolerances. Also, the utility of this index has been demonstrated through a selective assembly scheme applied to the drawer system problem. Though the index formulated in this study for seam appearance quality may be useful, future studies are necessary to make the model readily applicable to real problems.

• Journal of Radiation Industry
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• v.17 no.3
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• pp.309-320
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• 2023

A multi-purpose canister (MPC) was developed for the purpose of transportation, storage and disposal of spent nuclear fuel (SNF) and has the advantage of minimizing repackaging between management stages of SNF. Considering the typical rock characteristics in Korea, a disposal canister is expected to contain 4 assemblies of Pressurized water reactor (PWR) SNF. The capacity of the MPC should be similarly designed with the disposal canister. However, the MPC with four SNF assemblies is expected to be less efficient in transporting and storing compared to a large-capacity canister. Therefore, a preliminary concept was derived for an auxiliary equipment that can transport and store multiple MPCs in a large overpack. A previously derived concept from US was thoroughly reviewed, and the preliminary concept was revised considering domestic situations including crane capacity and others. In addition, the safety of the normal transportation and storage of the MPC placed in transportation and storage overpack was evaluated with the auxiliary equipment.