• 방사성폐기물학회지
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• 제11권4호
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• pp.293-301
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• 2013

처분공 처분 개념은 아프리카의 방사성폐기물관리 방안의 향상을 위해서 남아프리카에너지주식회사(NECSA)에서 처음으로 제시되었다. 초기에 방사성폐기물의 지층처분방안이 고려되었으나, 지하수를 방사성폐기물 오염으로부터 보호하는 방안과 토양과 지하 암석의 균열지대를 통한 방사성 물질의 이동에 대한 조사가 불가피하게 필요했다. 이러한 이유로 처분공 처분개념이 연구되었다. 처분공 처분 개념은 폐기된 밀봉선원을 상대적으로 좁은 직경(260 mm)의 처분공 시설을 통해 처리 및 처분한다. 탄자니아는 장반감기 및 단반감기의 폐기된 밀봉선원을 방사성폐기물관리시설에 저장하고 있으며 폐기된 밀봉선원의 방사능은 1E-6 Ci 에서 8.8E+3 Ci의 범위로 분포한다. 그러나 영구 처분 문제는 여전히 해결하지 못하고 있다. 본 연구에서는 처분부지 면적이 적고, 이에 따라 인간침입 위험이 줄어드는 처분공 처분개념을 제시하였다.

• Journal of Radiation Protection and Research
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• 제35권1호
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• pp.6-11
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• 2010

Embodying the safety of radioactive waste disposal requires the relevant safety criteria and the corresponding stylized methods to demonstrate its compliance with the criteria. This paper proposes a conceptual model of risk-based safety evaluation for integrating complex potential radiation exposure situations in radioactive waste disposal. For demonstrating compliance with a risk constraint, the approach deals with important exposure scenarios from the viewpoint of the receptor to estimate the resulting risk. For respective exposure situations, it considers the occurrence probabilities of the relevant exposure scenarios as their probability of giving rise to doses to estimate the total risk to a representative person by aggregating the respective risks. In this model, an exposure scenario is simply constructed with three components:radionuclide release, radionuclide migration and environment contamination, and interaction between the contaminated media and the receptor. A set of exposure scenarios and the representative person are established from reasonable combinations of the components, based on a balance of their occurrence probabilities and the consequences. In addition, the probability of an exposure scenario is estimated on the assumption that the initiating external factors influence release mechanisms and transport pathways, and its effect on the interaction between the environment and the receptor may be covered in terms of the representative person. This integrated approach enables a systematic risk assessment for complex exposure situations of radioactive waste disposal and facilitates the evaluation of compliance with risk constraints.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.378-390
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• 2023

The SPES (Selective Production of Exotic Species) facility, currently under development at Legnaro National Laboratories of INFN, aims at the production of intense RIB (Radioactive Ion Beams) employing the Isotope Separation On-Line (ISOL) technique for interdisciplinary research. The radioactive isotopes of interest are produced by the interaction of a multi-foil uranium carbide target with a 40 MeV 200 μA proton beam generated by a cyclotron proton driver. The Target Ion Source (TIS) is the core of the SPES project, here the radioactive nuclei, mainly neutron-rich isotopes, are stopped, extracted, ionized, separated, accelerated and delivered to specific experimental areas. Due to efficiency reasons, the TIS unit needs to be replaced periodically during operation. In this highly radioactive environment, the employment of autonomous systems allows the manipulation, transport, and storage of the TIS unit without the need for human intervention. A dedicated remote handling infrastructure is therefore under development to fulfill the functional and safety requirement of the project. This contribution describes the layout of the SPES target area, where all the remote handling systems operate to grant the smooth operation of the facility avoiding personnel exposure to a high dose rate or contamination issues.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.96-100
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• 2003

조사후시험시설에는 시설내의 부압기준을 다르게 설정하여 시설의 운전조건을 최적화로 유지하고 방사성물질을 처리하기 위한 오염배기를 포집하는 여과장치가 설치되어 있다. 필터 포집장치에 대해 관련된 효율시험과 검사를 주기적으로 수행하여 운전효율과 안전을 향상시키고 있다.

• 한국환경복원기술학회지
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• 제16권3호
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• pp.55-62
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• 2013

Generally, the radioactivity from NPP(Nuclear Power Plants) operation can be released below 3% of DRLs(Derived Release Limits) to environment. It was tried to understand which plant was efficient for absorbing radioactivity in this study. Pinus thunbergii Parl. and Viburnum awabuki K. KOCH were analyzed for radioisotope absorption. The samples were collected at three different locations depending on the distance from NPP at the vicinity 10km away, and 30km away. Gamma radionuclide was not detected from the samples, which means that the direct transition into the plant was not significant. Meanwhile, the very low level of radioactive tritium was detected in the samples. One remark was that every plant has different ability for tritium absorption. These results are expected to be applied to propagation and transplanting in radioactively contaminated area or reducing radioactivity in the soil and water near the plants.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.503-508
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• 2003

원자력 시설의 공기조화 시스템은 일반시설의 공기조화 시스템에 비하여 더 안정되고 여유있게 설치 및 시공되어야 한다. 그 목적은 최적 작업환경유지, 오염 공기로부터의 작업자 보호, 외부배기로 인한 대기오염 방지 등이다. 낮은 공기오염조차 막는 것이 원자력시설의 안전한 운전을 위해 기본적인 것이다. 설계 시 시스템의 융통성을 갖는 설계가 필요한데 이는 나중에 시스템의 수정보완 등을 고려할 때 중요하다. 본 논문에서는 원자력시설의 공기조화계통 설계에 고려해야 할 내용 및 외국시설에 대하여 검토하였는바, 원자력시설의 공기조화계통 설계에 활용될 수 있겠다.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.56-63
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• 2024

In high radiation fields, gamma cameras suffer from pulse pile-up, resulting in poor energy resolution, count losses, and image distortion. To overcome this problem, various methods have been introduced to reduce the size of the aperture or pixel, reject the pile-up events, and correct the pile-up events, but these technologies have limitations in terms of mechanical design and real-time processing. The purpose of this study is to develop a real-time gamma camera to evaluate the radioactive contamination in high radiation fields. The gamma camera is composed of a pinhole collimator, NaI(Tl) scintillator, position sensitive photomultiplier (PSPMT), signal processing board, and data acquisition (DAQ). The pulse pile-up is corrected in real-time with a field programmable gate array (FPGA) using the start time correction (STC) method. The STC method corrects the amplitude of the pile-up event by correcting the time at the start point of the pile-up event. The performance of the gamma camera was evaluated using a high dose rate ¹³⁷Cs source. For pulse pile-up ratios (PPRs) of 0.45 and 0.30, the energy resolution improved by 61.5 and 20.3%, respectively. In addition, the image artifacts in the ¹³⁷Cs radioisotope image due to pile-up were reduced.

• 한국산업정보학회논문지
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• 제16권4호
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• pp.37-44
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• 2011

본 논문은 원자력시설내의 방사성 표면오염을 측정평가하기 위한 표변오염도 시료채취용 자동화 시료채취기 개발에 있다. 시료채취를 위한 간접법은 사람에 의한 수동적인 시료 채취방법으로서 시료를 채취하는 사람에 따라 문지르는 횟수 강도 및 면적이 다르다. 이로 인하여 표면오염도 측정치의 정확도가 저하되고 시료 채취시마다 측정치의 오차가 많이 발생한다. 개발된 장치에 의한 방법은 기존방법에 의한 표면오염도의 측정치보다 smear paper의 방사성 시료가 균일하게 채취됨을 확인하였으며, 향후 표면오염도의 평가시 측정자료의 일관성을 확보하게 되었다.

• 방사선산업학회지
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• 제5권2호
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• pp.185-189
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• 2011

As nuclear industry has been developed, a various types of radiological contamination has occurred. After 9.11 terror in U.S.A., it has been concerned that terrorists' active area has been enlarged to use nuclear or radioactive substance. Recently, the most powerful earth-quake stroke, which triggered a massive tsunami in Japan and then Fukushima nuclear power plant reactor has suffered from a serious accident in history. The Fukushima reactor accident has occurred an anxiety of radiation leaks and about 170,000 people have been evacuated from the accidental area near the nuclear power plant. For these reasons, a social chaos can be occurred if radiological contamination occurs to the supply system for the drinking water. As such, the establishment of the radiation monitoring system for the city main water system is compelling for the national security. In this study, a feasibility test of radiation monitoring system which consists of unified hybrid-type radiation detectors was experimented for multi detection system by using gamma-ray imaging. The hybrid-type radiation sensors were fabricated with CsI(Tl) scintillators and photodiodes. A preamplifier and amplifier was also fabricated and assembled with the sensor in the shielding case. For the preliminary test of detection of radiological contamination in the river, multi CsI(Tl)-PIN photodiode radiation detectors and $^{137}Cs$ gamma-ray source were used. The DAQ was done by Linux based ROOT program and NI DAQ system with Labview program. The simulated contamination was assumed to be occurred at Gapcheon river in Daejeon city. Multi CsI(Tl)-PIN photodiode radiation detectors were positioned at the Gapcheon river side. Assuming that the radiological contaminations flows in the river the $^{137}Cs$ gamma-ray source has been moved and then, the contamination region was reconstructed.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.671-675
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• 2003

연구로 1,2호기 해체 사업이 본격적으로 착수하게 됨에 따라 2001년 8월부터 2002년 12월까지 연구로 2호기 부속시설인 동위원소 생산시설을 제염 및 해체하였다. 이 시설은 동위원소 생산용 콘크리트 핫셀, 납 핫셀 및 실험실로 구성되어 있다. 제염ㆍ해체의 대상물은 흄후드, 실험대, 씽크 및 오염된 내부 시설물이다. 안전한 해체 활동을 위해서 각종 지침서 및 절차서가 수립되었다. 해체 활동을 위해 총 20,933 man-hour의 인력이 소요되었고, 드릴링 머신 등 여러 장비가 투입되었다. 실험실에서의 최대 오염도는 유리성 오염도가 $\beta$ : 9.24 Bq/$\textrm{cm}^2$이였고, 고착성 오염도는 350,000 cpm이였다. 해체폐기물은 콘크리트류, 목재류 및 철재류 등으로 총 62.146 Ton이고, 작업자들의 피폭량은 0.33 mam-mSv로 나타났다.