• 방사성폐기물학회지
• /
• 제22권3호
• /
• pp.339-346
• /
• 2024

The spent nuclear fuel, combusted and released in the nuclear power plant, is stored in the spent fuel pool (SFP) located in the fuel buildings interconnected with the reactors. In Korea, spent fuel has been stored exclusively in SFPs, prompting initiatives to expand storage capacity by either installing additional SFPs or replacing them with high-density spent fuel storage racks. The installation of these fuel racks necessitates obtaining a regulatory license contingent upon ensuring safe fuel handling and storage systems. Regulatory agencies mandate the formulation of various postulated accident scenarios and assessments covering criticality, shielding, thermal behavior, and structural integrity to ensure safe fuel handling and storage systems. This study describes an evaluation method for assessing the structural damage to storage racks resulting from fuel dropping as a part of the functional safety evaluation of these racks. A scenario was envisaged wherein fuel was dropped onto the base plates of the upper and lower sections of the storage racks, and the impact load was analyzed using the ABAQUS/Explicit program. The evaluation results revealed localized plastic deformation but affirmed the structural integrity and safety of the storage racks.

• Nuclear Engineering and Technology
• /
• 제43권5호
• /
• pp.405-412
• /
• 2011

Used nuclear fuel will likely be stored dry for extended periods of time in the USA. Until a final disposition pathway is chosen, the storage periods will almost definitely be longer than were originally intended. The ability of the important-tosafety structures, systems, and components (SSCs) to continue to meet storage and transport safety functions over extended times must be determined. It must be assured that there is no significant degradation of the fuel or dry cask storage systems. Also, it is projected that the maximum discharge burnups of the used nuclear fuel will increase. Thus, it is necessary to obtain data on high burnup fuel to demonstrate that the used nuclear fuel remains intact after extended storage. An evaluation was performed to determine the conditions that may lead to failure of dry storage SSCs. This paper documents the initial technical gap analysis performed to identify data and modeling needs to develop the desired technical bases to ensure the safety functions of dry stored fuel.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 춘계학술대회논문집
• /
• pp.327-330
• /
• 2003

In this paper, a viscoelastic structural analysis for the spent pressurized water reactor(PWR) nuclear fuel disposal canister is carried out to predict the collapse of the canister while the canister is stored in a deep repository for long time. There may exist some subterranean heat in a deep repository while the nuclear fuel disposal canister is stored for long time. Then, a time-dependent viscoelastic structural deformation may occur in the canister due to the subterrnean heat Hence, the viscoelastic stress variation according to time should be computed to predict the structural strength of the canister. A viscoelastic material model is adopted. Analysis results show that even though some subterrnean heat may exist for quite a long time, the canister structure still endures stresses below the yield strength of the canister. Hence, some subterranean heat cannot seriously affect the structural strength of the canister.

• 방사성폐기물학회지
• /
• 제20권3호
• /
• pp.365-369
• /
• 2022

Operating and decommissioning nuclear power plants generates radioactive waste. This radioactive waste can be categorized into several different levels, for example, low, intermediate, and high, according to the regulations. Currently, low and intermediate-level waste are stored in conventional 200-liter drums to be disposed. However, in Korea, the disposal of intermediate-level radioactive waste is virtually impossible as there are no available facilities. Furthermore, large-sized intermediate-level radioactive waste, such as reactor internals from decommissioning, need to be segmented into smaller sizes so they can be adequately stored in the conventional drums. This segmentation process requires additional costs and also produces secondary waste. Therefore, this paper suggests repurposing the no-longer-used spent nuclear fuel casks. The casks are larger in size than the conventional drums, thus requiring less segmentation of waste. Furthermore, the safety requirements of the spent nuclear fuel casks are severer than those of the drums. Hence, repurposed spent nuclear fuel casks could better address potential risks such as dropping, submerging, or a fire. In addition, the spent nuclear fuel casks need to be disposed in compliance with the regulations for low level radioactive waste. This cost may be avoided by repurposing the casks.

• Preventive Nutrition and Food Science
• /
• 제1권1호
• /
• pp.75-79
• /
• 1996

The purpose of this study was to investigate the effect of vitamin {TEX}$B_{6}${/TEX} deficiency on the utilization and recuperation of stored fuel in exercising rats. Thirty six rats were fed either a vitamin {TEX}$B_{6}${/TEX} deficient diet(-{TEX}$B_{6}${/TEX}) or a control diet(+{TEX}$B_{6}${/TEX}) for 5 weeks, then subdivided into 3 group: non-exercise group(NE), exercise group(EX), exercise and recuperation group(EX). EX group were exercised in treadmill({TEX}$10^{o}${/TEX}, 0.5~0.8km/h)for 2 hours and ER group were recuperated three days with the respective diet after exercise. Glucose(GLU), glycogen(GLY), protein(PRO), trigyceride(TG) and free fatty acid(FFA) were compared in plasma(P), liver(L) and skeletal muscle(M) of rats. Compared to +{TEX}$B_{6}${/TEX} rats, in NE group, the level of L-GLY of -{TEX}$B_{6}${/TEX} rats was higher, M-TG, L-PRO of -{TEX}$B_{6}${/TEX} rats were lower and there were no differences in P-PRO, P-FFA, P-TG, M-GLY, M-PRO and L-TG. In EX group, the levels of P-FFA, L-PRO of -{TEX}$B_{6}${/TEX} rats were higher. P-TG, L-TG of -{TEX}$B_{6}${/TEX} rats were lower and there was no difference in L-GLY. In EG group, the levels of P-GLU, P-PRO, P-RG, L-PRO of -{TEX}$B_{6}${/TEX} rats were lower and there were no differences in L-GLY, L-TG, M-TG and M-GLY. these results suggest that a lowered intake of vitamin {TEX}$B_{6}${/TEX} may impair the recuperation of aminals after exercise related to exercise fuel stores although there is a compensation among stored fuel utilization during exercise.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2005년도 전력전자학술대회 논문집
• /
• pp.343-346
• /
• 2005

In this paper a power conditioning system suitable for the fuel cell powered off-road vehicle is proposed. The proposed system employs a Proton Exchange Membrane Fuel Cell stack combined with boost converter, a super capacitor module combined with hi-directional buck-boost converter, a 4-quadrant DC chopper and a permanent magnet DC motor. The momentary overload condition occurring during the motor starting is handled by the energy stored in the supercapacitor module. Also, the regenerative energy can be stored in the supercapacitor module by operating the system in either buck or boost mode. This capability gives the system designer the higher flexibility in designing the system and assures the lower cost of the system. The validity and feasibility of the proposed system is proven by the computer simulation.

• 한국압력기기공학회 논문집
• /
• 제16권1호
• /
• pp.110-116
• /
• 2020

As the management plan for domestic spent nuclear fuel is delayed, the storage of the operating nuclear power plant is approaching saturation, and the Kori 1 Unit that has reached its end of operation life is preparing for the dismantling plan. The first stage of dismantling is the transfer of spent nuclear fuel stored in storage at plants. The spent fuel management process leads to temporary storage, interim storage, reprocessing and permanent disposal. In this paper, the technical issues to be considered when transporting spent fuel in this process are summarized. The spent fuels are treated as high-level radioactive waste and strictly managed according to international regulations. A series of integrity tests are performed to demonstrate that spent fuel can be safely stored for decades in a dry environment before being transferred to an intermediate storage facility. The safety of spent fuel transport container must be demonstrated under normal transport conditions and virtual accident conditions. IAEA international standards are commonly applied to the design of transport containers, licensing regulations and transport regulations worldwide. In addition, each country operates a physical protection system to reduce and respond to the threat of radioactive terrorism.

• 신재생에너지
• /
• 제3권2호
• /
• pp.60-67
• /
• 2007

This paper describes the design and integration of the wind-fuel cell hybrid system. The hybrid system components included a wind turbine, an electrolyzer (for generation of H2), a PEMFC (Proton Exchange Membrane Fuel Cell), hydrogen storage tank and BOP (Balance of Plant) system. The energy input is entirely provided by a wind turbine. A DC-DC converter controls the power input to the electrolyzer, which produces hydrogen and oxygen form water. The hydrogen used the fuel for the PEMFC. Hydrogen may be produced and stored in high pressure tank by hydrogen gas booster system. Wind conditions are changing with time of day, season and year. So, wind power is a variable energy source. The main purpose with these WT-FC hybrid system is to store hydrogen by electrolysis of water when wind conditions are good and release the stored hydrog en to supply the fuelcell when wind is low.

• Nuclear Engineering and Technology
• /
• 제50권2호
• /
• pp.306-312
• /
• 2018

There is an increasing need in the United States and around the world to move used nuclear fuel from wet storage in fuel pools to dry storage in casks stored at independent spent fuel storage installations or interim storage sites. Under normal conditions, the Nuclear Regulatory Commission limits cladding temperature to $400^{\circ}C$ for high-burnup (>45 GWd/mtU) fuel, with higher temperatures allowed for low-burnup fuel. An analysis was conducted with FRAPCON-4.0 on three modern fuel designs with three representative used nuclear fuel storage temperature profiles that peaked at $400^{\circ}C$. Results were representative of the majority of US light water reactor fuel. They conservatively showed that hoop stress remains below 90 MPa at the licensing temperature limit. Results also show that the limiting case for hoop stress may not be at the highest rod internal pressure in all cases but will be related to the axial temperature and oxidation profiles of the rods at the end of life and in storage.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
• /
• pp.70-73
• /
• 2004

Fuel Cells are clean and efficient electrochemical devices that convert the chemical energy stored in a fuel with oxygen from air directly into usable electricity without using a conventional combustion process. Because of the great importance of proton conducting membranes in fuel cells for certain applications as mobile power generators, significant research efforts have been devoted to these membranes during the last 30 years.(omitted)