• Nuclear Engineering and Technology
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• 제17권3호
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• pp.185-192
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• 1985

가압경수로에서 나오는 사용후 핵연료의 fissile 양은 CANDU형 원자로에 쓰는 천연우라늄의 농축도 보다 높다. 따라서 핵연료 활용을 다양화하고 점차 누적되고 있는 가압경수로의 사용후 핵 연료의 저장문제를 부분적으로나마 해결하기 위하여, 가압경수로의 사용후 책 연료를 CANDU 형 원자로에 사용하는 방안을 검토 하였다. 가압경수로에서 나온 사용후 핵 연료에서 가공되는 혼합핵연료(Mixed Oxide Fuel)를 CANDU형 원자로에 장전하였을 경우, WIMS/D 코드를 이용하여 핵적특성을 분석하였다. 그리고 본 분석에서는 현 CANDU형 원자로의 반응도 조절장치를 변경시키지 않고 혼합핵 연료를 CANDU형 원자로에 사용할 수있는 방안만 조사하였다.

• 한국항공운항학회지
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• 제19권2호
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• pp.58-63
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• 2011

A Continuous Descent Approach(CDA) is defined as a simple, cost-effective, noise and emission abatement technique for any powered aircraft on approach. CDA also can be optimised within energy, speed and safety constraints by avoiding unnecessary flap, air brake and engine thrust. This study includes comparison on fuel consumption between Continuous Descent type and Step Down type by using flight data. In particular, we investigated fuel flow per hour, calibrated airspeed and pressure altitude for all flight time. During descent flight, the fuel consumption of Continuous Descent type was less than the fuel consumption of Step Down type.

• 설비공학논문집
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• 제7권3호
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• pp.353-358
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• 1995

The emission characteristics of a semi-Bunsen type burner for gas boilers were studied experimentally. The experimental results reveal that nitric oxide emission increases with fuel flow rate. It is linearly proportional to total fue flow rate at a small amount of fuel up to 0.4 liters per minute. It does not change significantly within the range of fuel flow rate from 0.4 to 1.2 liters per minute per nozzle and increases at large fuel flow rate. The carbon monoxide emission reveals to be dependent upon the fuel flow rate per each nozzle and the number of fuel injection nozzles. Diameter of an injection nozzle could have an effect on the emission characteristics of this type of burners. However, there is no marked change in the nitric oxide emission if the total fuel flow rate is same with different nozzle sizes.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2415-2421
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• 2020

The axial heterogeneous void distribution in a fuel channel is a relevant and important issue during nuclear reactor analysis for LWR, especially for boiling water channel-type reactors. Variation of the coolant density in fuel channel has an effect on the neutron spectrum that will in turn have an impact on the values of absolute reactivity, the void reactivity coefficient, and the fuel isotopic compositions during irradiation. This effect is referring to as the history effect in light water reactor calculations. As the void reactivity effect is positive in RBMK type reactors, the underestimation of water density heterogeneity in 3D reactor core numerical calculations could cause an uncertainty during assessment of safe operation of nuclear reactor. Thus, this issue is analysed with different cross-section libraries which were generated with WIMS8 code at different reference water densities. The libraries were applied in single fuel model of the nodal code of QUABOX-CUBBOX/HYCA. The thermohydraulic part of HYCA allowed to simulate axial water distribution along fuel assembly model and to estimate water density history effect for RBMK type fuel.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4477-4490
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• 2023

Fuel locking mechanisms (FLMs) are essential in upward-flow research reactors to prevent accidental fuel separation from the core during reactor operation. This study presents a novel design concept for a remotely controlled plate-type nuclear fuel locking mechanism. By employing electromagnetic field analysis, we optimized the design of the electromagnet for fuel unlocking, allowing the FLM to adapt to various research reactor core designs, minimizing installation space, and reducing maintenance efforts. Computational flow analysis quantified the drag acting on the fuel assembly caused by coolant upflow. Subsequently, we performed finite element analysis and evaluated the structural integrity of the FLM based on the ASME boiler and pressure vessel (B&PV) code, considering design loads such as dead weight and flow drag. Our findings confirm that the new FLM design provides sufficient margins to withstand the specified loads. We fabricated a prototype comprising the driving part, a simplified moving part, and a dummy fuel assembly. Through basic operational tests on the assembled components, we verified that the manufactured products meet the performance requirements. This remote-controlled micro locking mechanism holds promise in enhancing the safety and efficiency of plate-type nuclear fuel operation in upflow research reactors.

• 한국자동차공학회논문집
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• 제15권3호
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• pp.99-105
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• 2007

Currently, BLDC fuel pump was applied on LPi vehicle using 3rd fuel supply system as liquified phase LPG injection method had already shown better performance than others. Its cost, however, is rather expensive because of drawbacks such as complicated structure, a fault of localization of system. In this work, demonstration system for a developed turbine type fuel pump to replace BLDC system was setup and investigated. This study results that fuel mass flow rate of turbine type pump and injection performance of injector were better compared to BLDC type. Comparing flow rate of summer LPG with that of winter LPG, the flow rate decreased about 25% using winter LPG. Performance applying turbine type LPi fuel pump to engine is confirmed.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1556-1568
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• 2021

The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect stress conditions, mechanical behaviors and thermal-hydraulic performance of the fuel assembly. This paper is the Part II work of a two-part study devoted to analyzing the complex unique mechanical deformation and thermal-hydraulic characteristics for the typical plate-type fuel assembly under irradiation effect, which is on the basis of developed and verified numerical thermal-fluid-structure coupling methodology under irradiation in Part I of this work. The mechanical deformation, thermal-hydraulic performance and Mises stress have been analyzed for the typical plate-type fuel assembly consisting of support plates under non-uniform irradiation. It was interesting to observe that: the plate-type fuel assembly including the fuel plates and support plates tended to bend towards the location with maximum fission rate; the hot spots in the fuel foil appeared at the location with maximum thickness increment; the maximum Mises stress of fuel foil was located at the adjacent location with the maximum plate thickness increment et al.

• 한국분무공학회지
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• 제16권1호
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• pp.1-6
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• 2011

In recent years, the need for more fuel-efficient and lower-emission vehicles has driven the technical development of alternative fuels such as LPG (Liquefied Petroleum Gas) which is able to meet the limits of better emission levels without many modifications to current engine design. LPG has a high vapor pressure and lower viscosity and surface tension than diesel and gasoline fuels. These different fuel characteristics make it difficult to directly apply the conventional gasoline or diesel fuel pump. Self acting lubricated groove design or coating can be used in high-speed and high precision spindle system like a roller-vane type fuel pump, because of its advantages such as low frictional loss, low heat generation, averaging effect leading better running accuracy and simplicity in manufacturing. Those design method can also affect the atomization of fuel from the injector and the formation of fuel film on the intake manifold. In this study, experiments are carried out to get performance characteristics of initial and steady state operation, The characteristics of vane type fuel pump were investigated to access the applicability on LPLi engine.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.94-101
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• 2001

In this paper, the combustion improvement effects of alcohol-diesel oil blend fuel were investigated in a visualization engine. As a result of experiment, it was found out that the combustion chamber of deep dish type and re-entrant type at the same operation condition. However, when the con-tent of alcohol exceeded 10% of total fuel delivery, the combustion of alcohol-diesel oil blend fuel was worse than that of diesel oil. The maximum blend quantity of ethanol which is not ignited in the re-entrant type combustion chamber was estimated at approximately 40% of total fuel delivery. So, it is necessary to blend appropriate quantity of a volatility fuel such as alcohol in order to improve combustion.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2874-2879
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• 2020

Due to excess reactivity, fresh nuclear fuel often contains burnable poisons. This research looks at six different burnable poisons and their impacts on reactivity, material attractiveness, and waste management. An MCNP simulation of a PWR fuel pin was performed with a fuel burnup of 60 GWd/MTHM to determine when each burnable poison fuel type would decrease below a k_∞ of 1. For determining the plutonium material attractiveness in each burnable poison fuel type, the plutonium isotopic content of the used fuel was evaluated using Bathke's Figure of Merit formula. For the waste management analysis, the thermal output of each burnable poison fuel type was determined through ORIGEN decay simulations at 100 and 300 years after being discharged from the core. The performance of all six burnable poisons varied over the three criteria considered and no single burnable poison performed best in all three considerations.