• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1394-1405
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• 2022

The importance of ensuring the inherent safety and security has been more emphasized in recent years to demonstrate the integrity of nuclear facilities under external human-induced events (e.g. aircraft crashes). This work suggests a simulation methodology to effectively evaluate the impact of a commercial aircraft engine onto a dry storage facility. A full-scale engine model was developed and verified by Riera force-time history analysis. A reinforced concrete (RC) structure of a dry storage facility was also developed and material behavior of concrete was incorporated using three constitutive models namely: Continuous Surface Cap, Winfrith, and Karagozian & Case for comparison. Strain-based erosion limits for concrete were suitably defined and the local responses were then compared and analyzed with empirical formulas according to variations in impact velocity. The proposed methodology reasonably predicted such local damage modes of RC structure from the engine missile, and the analysis results agreed well with the calculations of empirical formulas. This research is expected to be helpful in reviewing the dry storage facility design and in the probabilistic risk assessment considering diverse impact scenarios.

• 방사성폐기물학회지
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• 제21권4호
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• pp.531-541
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• 2023

The Wolsong Nuclear Power Plant (NPP) operates an on-site spent fuel dry storage facility using concrete silo and vertical module systems. This facility must be safely maintained until the spent nuclear fuel (SNF) is transferred to an external interim or final disposal facility, aligning with national policies on spent nuclear fuel management. The concrete silo system, operational since 1992, requires an aging management review for its long-term operation and potential license renewal. This involves comparing aging management programs of different dry storage systems against the U.S. NRC's guidelines for license renewal of spent nuclear fuel dry storage facilities and the U.S. DOE's program for long-term storage. Based on this comparison, a specific aging management program for the silo system was developed. Furthermore, the facility's current practices-periodic checks of surface dose rate, contamination, weld integrity, leakage, surface and groundwater, cumulative dose, and concrete structure-were evaluated for their suitability in managing the silo system's aging. Based on this review, several improvements were proposed.

• 한국압력기기공학회 논문집
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• 제17권2호
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• pp.65-74
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• 2021

This study aims to assess the effect of postulated seismic loads on the structural integrity of a spent nuclear fuel dry storage facility. Firstly, three-dimensional modal and response spectrum analyses were carried out. With regard to the latter analysis, the effect of incident angles against two horizontal and one vertical response spectra was also considered. Results showed that even though two critical locations were predicted at the longitudinal axis central part of upper flow path as well as the end discontinuity part of upper and lower flow paths connector, their maximum principal stress values were less than the tensile strength. Moreover, since the influence of vertical angle was 87% higher than that of horizontal angle in particular, which should be carefully handled to demonstrate integrity of the facility.

• 방사성폐기물학회지
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• 제19권2호
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• pp.205-214
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• 2021

Currently, the interim storage pools of spent fuels in South Korea are expected to become saturated from 2024. It is required to prepare an operation plan of a domestic dry storage facility during a long-term period, with the researches on safety evaluation methods. This study modified the FRAPCON code to predict the spent fuel integrity evaluation such as the axial cladding temperature, the hoop stress and hydrogen distribution in dry storage. The cladding temperature in dry storage was calculated using the COBRA-SFS code with the burnup information which was calculated using the FRAPCON code. The hoop stress was calculated using the ideal gas equation with spent fuel information such as rod internal pressure. Numerical analysis method was used to calculate the degree of hydrogen diffusion according to the hydrogen concentration and temperature distribution during a dry storage period. Before 50 years of dry storage, the cladding temperature and hoop stress decreased rapidly. However, after 50 years, they decreased gradually and the cladding temperature was below 400 K. The initial temperature distribution and hydrogen concentration showed a parabolic line, but hydrogen was transferred by the hydrogen concentration and temperature gradient over time.

• KIEAE Journal
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• 제16권6호
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• pp.103-108
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• 2016

Purpose: This study has developed economical and environmentally friendly storage type infiltration facilities that securing storage space inside the infiltration facility. It focused on preventing flooding rainfall as well as securing more groundwater through rainwater infiltration that is valuable for the dry season. In addition, this study compares the installation cost of the storage-type infiltration facility to the cost of the conventional rainwater management facilities to demonstrate the economic efficiency of the storage-based infiltration facility. Method: Unit infiltration of this facility is calculated and when it was applied to a certain capacity, the amount of countermeasures are proposed in case study. Result: Unit infiltration of it is $0.2541m^3/hr$ and un it Temporary storage of it is $1.054m^3/m$. As a result, the infiltration effect of this facility is $1.306m^3/hr$. The cost was approximately 30% reduction in time to apply the storage type infiltration facility as compared with the case to apply the existing penetration of the facilities. Since the penetration of the existing facilities is smaller than that and it has much securing volume to process the same the amount of countermeasures. Therefore, it is determined that the cost significantly increases in material cost part. On the other hand, storage type infiltration facility is installed a small quantity because Unit Temporary storage and infiltration are bigger than that. So, it occurred to reduce material and installation costs.

• Nuclear Engineering and Technology
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• 제45권4호
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• pp.427-438
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• 2013

In this paper we discuss spent fuel management options in the Republic of Korea (ROK) from two interrelated perspectives: Centralized dry cask storage and spent fuel pyroprocessing and burning in sodium fast reactors (SFRs). We argue that the ROK will run out of space for at-reactors spent fuel storage by about the year 2030 and will thus need to transition centralized dry cask storage. Pyroprocessing plant capacity, even if approved and successfully licensed and constructed by that time, will not suffice to handle all the spent fuel discharged annually. Hence centralized dry cask storage will be required even if the pyroprocessing option is successfully developed by 2030. Pyroprocessing is but an enabling technology on the path leading to fissile material recycling and burning in future SFRs. In this regard we discuss two SFR options under development in the U.S.: the Super Prism and the Travelling Wave Reactor (TWR). We note that the U.S. is further along in reactor development than the ROK. The ROK though has acquired more experience, recently in investigating fuel recycling options for SFRs. We thus call for two complementary joint R&D project to be conducted by U.S. and ROK scientists. One leading to the development of a demonstration centralized away-fromreactors spent fuel storage facility. The other involve further R&D on a combined SFR-fuel cycle complex based on the reactor and fuel cycle options discussed in the paper.

• 방사성폐기물학회지
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• 제15권4호
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• pp.391-402
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• 2017

한국원자력환경공단에서는 국내 경수로 원전에서 발생된 사용후핵연료를 건식으로 저장할 수 있는 콘크리트 용기를 개발하였다. 본 저장용기는 사용후핵연료가 건식환경에서 장기간 저장되는 동안 용기 및 사용후핵연료의 건전성이 유지되며, 방사선량률이 저장시설의 설계기준을 초과하지 않도록 설계되어야 한다. 특히, 저장시설은 정상 및 사고조건에서 적절한 방사선 방호를 위한 차폐설계가 이루어져야 한다. 이를 위해 본 연구에서는 미국 10CFR72 및 10CFR20의 기술기준과 NRC의 표준 심사지침 NUREG-1536에서 제시한 평가방법에 따라 건식저장조건하에서 단일 콘크리트용기 및 $2{\times}10$ 용기배열조건의 선량율을 평가하였다. 평가결과, 일반인에 대한 연간선량 한도인 0.25 mSv를 만족하는 통제구역 경계까지의 거리는 약 230 m로 도출되었다. 콘크리트 저장용기의 설계사고는 $2{\times}10$ 배열의 저장시설에서 한 개의 저장용기가 이송 중 전도사고가 발생하여 용기의 바닥면이 통제구역 경계로 향하는 상황으로 가정하였다. 전도된 저장용기의 바닥면으로 부터 100 m 및 230 m 지점에서 각각 12.81 mSv 및 1.28 mSv로 평가되었다. 본 연구를 통해 건식저장조건에서 콘크리트 저장용기 및 저장시설은 적절하게 평가된 통제구역경계까지의 거리가 확보된다면 방사선적 안전성이 유지됨을 확인할 수 있었다. 본 평가결과만으로 건식환경의 저장용기(시설) 설계에 직접 적용하기는 어렵겠으나, 향후 '국가 고준위폐기물 관리 전략'에 근거한 원전내 저장시설 또는 중간저장 시설의 설계 및 운영에 유용한 자료가 될 것으로 사료된다.

• Nuclear Engineering and Technology
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• 제55권10호
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• pp.3898-3906
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• 2023

The paper notes that the most common way of handling spent nuclear fuel (SNF) of power reactors is its temporary long-term dry storage. At the same time, the operation of the dry spent fuel storage facilities almost never use the modern capabilities of information systems in safety control and collecting information for the next studies under implementation of aging management programs. The author proposes a structure of an information system that can be implemented in a dry spent fuel storage facility with ventilated storage containers. To control the thermal component of spent fuel storage safety, a database structure has been developed, which contains 5 tables. An algorithm for monitoring the thermal state of spent fuel was created for the proposed information system, which is based on the comparison of measured and forecast values of the safety criterion, in which the level of heating the ventilation air temperature was chosen. Predictive values of the safety criterion are obtained on the basis of previously published studies. The proposed algorithm is an implementation of the information function of the system. The proposed information system can be used for effective thermal monitoring and collecting information for the next studies under the implementation of aging management programs for spent fuel storage equipment, permanent control of spent fuel storage safety, staff training, etc.

• Journal of Radiation Protection and Research
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• 제37권4호
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• pp.197-201
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• 2012

경수로 사용후핵연료 중간저장시설의 부지면적을 산출하기 위하여 콘크리트 저장시설 개념모델의 연간선량을 계산하였다. 초기농축도 4.5 wt%, 연소도 45,000 MWd/MTU, 냉각기간 10년인 사용후핵연료를 대상으로 ORIGEN-ARP를 사용하여 선원항을 생산하였으며, MCNP 코드를 사용하여 저장시설에 대한 모델링 및 방사선차폐계산을 수행하였다. 연간선량은 저장시설의 용량별로 계산하였으며, 중앙집중식 저장시설의 경우, 반경 700 m 이상에서 10CFR72에서 권고하는 통제구역 경계에서의 연간선량 기준 0.25 mSv를 만족하였다.

• Journal of Radiation Protection and Research
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• 제38권4호
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• pp.189-193
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• 2013

경수로 사용후핵연료 건식 중간저장시설 격납건물 크기에 따른 방사선량률 추이 분석을 위하여 격납건물 외부 벽면에서의 추정연간선량을 계산하였다. ORIGEN-ARP를 사용하여 농축도 4.5 wt%, 연소도 45,000 MWd/MTU 냉각기간 10년인 사용후핵연료를 대상으로 선원항을 생산하였으며, MCNP 코드를 사용하여 저장시설 및 격납건물에 대한 모델링 및 선량률 계산을 수행하였다. 연간선량은 격납건물 외부 벽면에서의 값으로 계산하였으며, 격납건물 벽과 최외곽 배열의 저장용기와의 간격을 50 m 이상으로 설정할 경우 10CFR72에서 제시하는 연간선량인 0.25 mSv 이하의 값이 계산되었다.