• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.229-244
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• 2024

Recently, supply chain attacks against nuclear facilities such as "Evil PLC" are increasing due to the application of digital technology in nuclear power plants such as the APR1400 reactor. Nuclear supply chain security requires a asset management system that can systematically manage a large number of providers due to the nature of the industry. However, due to the nature of the control system, there is a problem of inconsistent management of attribute information due to the long lifecycle of software assets. In addition, due to the availability of the operational technology, the introduction of automated configuration management is insufficient, and limitations such as input errors exist. This study proposes a systematic asset management system using SBOM(Software Bill Of Materials) and an improvement for input errors using natural language processing techniques.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.551-551
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• 2017

우리나라와 동아시아는 경제 성장에 따른 전력수요가 크게 증가하였으며, 증가하는 대부분의 전력수요를 원자력으로 대체하고자 원전을 통한 전력생산 비중을 증가시키고 있다. 현재 중국은 13기의 원전을 가동 중이며, 동남 해안지대에 집중되어 있다. 또한, 건설 중인 원전은 27기로 전세계에서 건설 중인 원전의 41%를 차지한다. 원전의 증가에 따른 방사능 누출에 대한 위험성 역시 증가되고 있는 실정이다. 한국원자력안전기술원에서 중국 중서부지역에서 방사능이 누출될 경우 방사성 물질이 한반도로 이동하는 모의 상황에 대한 시뮬레이션을 통해, 원전 사고 발생 시 사흘 만에 제주도를 포함한 대한민국 전역이 방사성 물질로 뒤덮이는 것으로 분석하였다. 중국에서 누출된 방사성물질은 편서풍을 타고 한반도로 이동하게 되며, 일부는 낙진으로 유역 또는 하천에 유입되고 일부는 동해를 지나 일본으로 이동 할 것이다. 그동안 중국에서의 방사능 누출사고를 통한 방사성물질의 국내유입에 의한 영향에 대한 연구가 부족한 것이 현실이다. 이에 본 연구에서는 중국 텐완에서 원전사고 발생시 국내 하천에 어떠한 영향을 미치는지 분석하고자 환경다매체 모형을 이용하여 방사성물질(세슘, Cs-137)의 영향에 대한 모의를 진행하였다. 중국 텐완원전에서 방사성 Cs-137이 누출되어 춘천지역에 도달하였을 때의 대기중 농도 $5,650Bq/m^3$로 가정하여 모의 시나리오를 구성하였다. 모의 지역은 북한강 수계를 대상으로 하였으며, 7개의 중권역과 549.3 km의 하천이 포함되었다. 다매체 모형 모의를 통해 방사성물질 낙진으로 인한 Cs-137이 북한강 수계에 어떠한 영향을 미치는지 알아보고자 북한강수계의 팔당댐 부근의 오염농도를 모의하였다. 우리나라의 원자력시설 방호 방재법에 따른 상수원 취수기준(먹는물)은 100 Bq/L로 되어있다. 본 연구의 시나리오 모의결과, 모의 1일차에서 45 Bq/L, 모의 8일차에는 먹는물 기준 100 Bq/L를 초과하여 최대 119.56 Bq/L로 오염되는 것으로 모의되었다. 따라서, 반감기가 큰 방사성물질을 유입으로 오염된 하천은 개선하기 위해서는 오랜 시간과 높은 처리비용이 발생되기 때문에 인접국 또는 국내의 방사능 누출로 인한 상수원 오염 발생에 대비한 초기/중 장기적인 대응책 마련이 필요한 시점이다.

• Journal of Radiation Protection and Research
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• v.31 no.4
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• pp.211-217
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• 2006

For more realistic assessment of Korean food chain radiation doses due to the operation of nuclear facilities, it is required to use domestically produced data for radionuclide transfer parameters in crop plants. This paper analyzed results of last about 10 year's studies on radionuclide transfer parameters in major crop plants by the Korean Atomic Energy Research Institute, comparing with the published international data, and consequently suggested the proper parameters to use. The trends of transfer parameter shows normal distributions if we have a lot of experimental data, but some radionuclides showed enormous variations with the environment of experimental, crops and soils. These transfer factors can be used to assess realistic radiation doses or to predict the doses in crops for normal operation or accidental release. Some kinds of parameter can be produced as conservatives or fragmentary results because soil-to-plant transfer factors were measured through greenhouse experiments which sometimes showed improper field situations. But these parameters mentioned in this paper can be representative of the status of Korean food chain than that of foreign country.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.1-8
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• 2016

The Nuclear Power Plants(: NPP) are being protected as national infrastructure, and instrumentation and control(: I&C) systems are one of the principle facilities of the NPP, which perform the protection, control, and monitoring function. The I&C systems are being evolved into digitalization based on computer and network technology from analog system. In addition, the I&C systems are mostly employ the specialized logic controllers which are dedicated for the NPP, but the usage of generalized IT resources are steadily increased. The cyber security issues for the NPP are being emerged due to cyber incidents by Stuxnet and various accidents in the NPP. In this paper, hybrid access control model is proposed which are applicable to I&C system by analyzing the access control requirements specified in regulatory guides. The safety of in-service and under construction of NPP are effectively increased by applying proposed hybrid model.

• Journal of the Korean Society of Radiology
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• v.9 no.3
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• pp.125-130
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• 2015

RI & RG are used in various field such as medical field, industrial field, agricultural and food&life field. The number of small nuclear facilities is on the increase. We need to take an interest in decommissioning of small nuclear facility and predict the occurring problem from facility decommissioning. Because of the relatively low radiation risk, the preparation of the small nuclear facility dismantling is often neglected. As the accident in Goiania, Brazil showed, the impact of the decommissioning of small nuclear facilities is not less than the large nuclear facilities although it may seem dangerless. Therefore, we analyzed the each institutional characteristics of the decommissioning of small nuclear facilities through foreign case study on this research. Also, we proposed several considerations on decommissioning such as reuse of facility and source, lack of space, stakeholder involvement and failures of protection. Through these study, we tried to make guideline of the small nuclear facilities decommissioning.

• Journal of Radiation Protection and Research
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• v.33 no.3
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• pp.121-126
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• 2008

Radioactivities of the stack air effluents from the Advance Fuel Science Building (AFSB) at KAERI have been investigated and evaluated. In this AFSB, nuclear fuels for the HANARO research reactor have been fabricated and the advanced nuclear fuels have been studied. A stack air monitoring system has been continuously operating to monitor the stack air effluents from the facility to protect the environment. As the results of the periodical radioactivity measurement and both the gamma and alpha spectrometry for the millipore filters taken from the stack air monitor from January until March 2008, a trace amount of primordial $^{40}K$ and the short-lived decay products of natural borne $^{222}Rn$ and $^{220}Rn$ have been detected. However, the radioactivities have rapidly decayed to the level below the Minimum Detectable Activity (MDA) of the counting system. Therefore, it was evaluated that no uranium isotopes have been released to the atmosphere from the stack of the AFSB at KAERI.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.262-264
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• 2000

원자로 내에서 연소 중인 핵연료나 저장 또는 재처리 중인 사용후핵연료의 성분으로서 시설의 공정설계, 안전성분석 및 차폐설계에 중요한 입력자료가 되는 핵분열생성물질, 방사화생성물 및 악티나이드의 핵종 농도와 이에 대응하는 방사능 강도의 기기 별 시간변 화율을 해석할 수 있는 코드 개발할 목적으로 MULTISAMS 정상 평형상태 모델을 구현하였다. MULTISAMS 코드의 반응공정 모델은 서로 연결되어 있으며 내부에 방사성물질의 혼합유체가 순환하는 세 종류의 반응기(원자로, 열교환기 및 화학반응기) 계통에서 자연적 또는 설계에 의해 일어나는 현상으로서; 반응기 간의 물질 흐름; 각 반응기 내에서 방사성 붕괴, 변환, 이동과 중성자 흡수 및 핵분열; 외부로부터 특정 핵종의 유입혹은 유출을 고려한 시간종속 핵종농도보존방정식 이론에 근거한다. 코드의 유용성 및 신뢰성을 검증하기 위해 현재 개념설계가 진행 중인 AMBIDEXTER원자력 에너지시스템을 대상으로 ORIGEN2 계산과 비교하였다. 두 코드 간의 입력조건과 배경이론차이점 때문에 절대적 비교가 불가능하므로 단순이론의 중간매개코드로서 SAMS를 이용한 2단계 비교방법을 따랐다. 결론은 MULTISAMS는 ORIGEN2 계산의 수렴치와 근사하게 일치하면서 ORIGEN2 가 다룰 수 없는 핵주기 연속후처리공정의 정상가동 시 핵종 평형농도를 기기 별로 계산할 수 있다는 장점을 확인하였다.

• Journal of Radiation Protection and Research
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• v.20 no.1
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• pp.8-15
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• 1995

An estimate of a change in radioactivity's circumstances around the nuclear power plant is validated with the results of the radioactivity measurements are compared. In this study, to further enhance the reliability of the results obtained from the environmental radioactivity measurements and analysis around the nuclear power plants that have been carried out up to the present. In the korea standard, there is the technical analysis guide for general stable chemical element's, but there is not the technical analysis guide for the radionuclei. therefore the environmental sample collection, the pretreatment of the sample and radionuclide analysis in the sample, the result's of the environmental radioactivity measurements by each organization, etc. are different. It is not sufficient for the database to forecasting a change in radioactivity's circumstances. A comparative study of collection and pretreatment techniques for the soil sample, the results by comparison, the method of minimizing the relative error are proposed. At one side of sample collection, there are going to considered that the surroundings of sample collection like the lay of the land, the provision of the selection standard for the area and pathway of radionuclide adhesion, the coherence of sample collection, etc.. at another side of pretreatment of the sample and measurement in the case of soil sample, how to do homogeneously the soil particle size and the standard tools, i.e. kinds of meshes, must to be selected.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.228-233
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• 2013

It has been continuously generated the requirement for the replacement of the main components such as a steam generator due to the deterioration of the nuclear power plant all around the world. Also, a large amount of radioactive metal was generated during the decommissioning in a short period. It is required to make an accurate measurement of the residual radioactivity for recycling the metal waste for releasing from regulatory control. In planning the measurement procedures, the influence of geometry, self-absorption, density and other relevant factors on the representativeness of the measurements should be considered for the decommissioning metal waste. In this study, the method for measurement procedures, the source term evaluation, the ways to secure representative samples, the measurement device for wide area and the self-absorption correction factors for different density were evaluated. The metal samples for measurement were prepared for securing the simple geometry and representative by melting process. The developed correction method for measuring the radioactivity a variety density of metal waste could improve the reliability of the evaluation results for clearance.

• Journal of the Korean Electrochemical Society
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• v.2 no.4
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• pp.183-189
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• 1999

A study on the destruction of organic cation and anion exchange resins by electro-generated Ag(II) as a mediator was carried out to develop the ambient-temperature aqueous process, known as Ag(II)-mediated electro-chemical oxidation (MEO) process, for the treatment of a large quantity of spent organic ion exchange resins as the low and Intermediated-level radioactive wastes arising from the operation, maintenance and repairs of nuclear facilities. The effects of controllable process parameters such as applied current density, temperature, and nitric acid concentration on the MEO of organic ion exchange resins were investigated. The cation exchange resin was completely decomposed to $CO_2$. The current efficiency increased with a decrease in applied current density while nitric acid concentration and temperature on the MEO of cation exchange resin did not affect the MEO. On the other hand, anion exchange resins were decomposed to CO and $CO_2$. The ultimate conversion to CO was about $10\%$ regardless of temperature. The destruction efficiencies to $CO_2$ were dependent upon temperature and the effective destruction of anion exchange resin could be obtained above $60^{\circ}C$.