• Nuclear Engineering and Technology
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• 제54권3호
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• pp.984-990
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• 2022

Corrosion release behavior of Alloy 690 in high-temperature water was investigated under the conditions of injected Zn concentrations of 0 ppb, 10 ppb and 50 ppb. A protective oxide film composed of Zn(Fe_xCr_1-x)₂O₄ and Cr₂O₃ was formed with Zn injection, resulting in a better corrosion resistance. In comparison with the Zn-free condition, the corrosion release rate under the Zn-injection conditions was smaller. The corrosion release inhibiting factors were 1.7 and 1.9 under the conditions of 10 ppb and 50 ppb Zn-injection respectively. A foreseen application of the corrosion and corrosion release rates has been proposed and discussed.

• 방사성폐기물학회지
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• 제19권2호
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• pp.177-186
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• 2021

Radioactive materials from nuclear power facilities can be released into the atmosphere through various channels. Recently, the dispersion of radioactive materials has become critical issue in Korea after Kori Unit 1 and Wolsong Unit 1 were permanently shut down. In this study, annual atmospheric dispersion factors were compared based on the continuous release and purge release using the XOQDOQ computer program, a method for calculating atmospheric dispersion factors at commercial nuclear power stations. The meteorological data analyzed in this study was based on the Shin Kori nuclear power meteorological tower which has the largest operating nuclear power plants in Korea, for three years (from 2008 to 2010). The analysis results of the dispersion factor of the radioactive material release obtained using the XOQDOQ program showed that the difference between the continuous release and purge release was within two times. This study will be valuable helpful for revealing the uncertainty of the predictive atmospheric dispersion factor to achieve regulation.

• Journal of Pharmaceutical Investigation
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• 제30권3호
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• pp.207-211
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• 2000

The objective of this work is to investigate the effect of molecular weight of poly(ethylene oxide) (PEO) and release medium on the release of nifedipine (NP) from PEO tablets containing NP and to get some mechanistic insights into the release of NP. The tablets containing NP were prepared by direct compression, using a flat-faced punch and die. The molecular weights of PEOs used were 200K, 900K, 2000K and 7,000K. The release kinetics were studied for 24 hours in aqueous ethanol solution, using a dissolution tester at $36.5^{\circ}C$ and 100 rpm. Drug release rate increased, as the concentration of ethanol in the dissolution medium increased, due to the increased solubility of NP. As the molecular weight of PEO increased, release rate decreased, due to the slower swelling and dissolution of PEO. The power values obtained by fitting data to the power law expression $(M_t/M_{\infty}=kt^n)$ indicated that, at low ethanol concentration, the release of NP is governed by anomalous diffusion. However, as the ethanol concentration increases, diffusional release becomes to prevail over anomalous or zero-order release. Overall, these results provided some insights into the release of NP from PEO tablet.

• 대한물리의학회지
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• 제1권1호
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• pp.49-57
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• 2006

Purpose : The Purpose of this study was to pain release and power grip in wrist affect of needle TENS(utilized of TENS in electrotherapy with oriental needle) and ultrasound therapy and taping with carpal tunnel syndrome patients. Methods : To study divided of each groups. each groups were apply to ultrasound therapy for 5 mintus, Taping was attached from wrist joint to elbow joint medial epicondly after maximum extension. needle TENS application was following of median nerve in wrist. Result : 1. The pain was released on needle TENS, ultrasound and taping groups of all(p<.05). 2. Power grip was enhanced in needle TENS and taping groups(p<.05) but ultrasound was no difference compared with before therapy. 3. Compared with needle TENS and taping therapy about pain release was needle TENS groups better than ultrasound groups(p<.05) Conclusion : Needle TENS, taping therapy are more effectable than ultrasound therapy for grip power and pain release. Needle TENS therapy is more effectable than taping therapy for pain release. Therefor, neddle TENS therapy is most effectable for pain release with carpal tunnel syndrome patients.

• 한국방사선학회논문지
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• 제9권5호
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• pp.269-277
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• 2015

세계적으로 수명을 다한 원자력발전소들이 증가하면서 노후화 된 원전의 해체에 대한 관심도 커져가고 있다. 특히 국토가 좁고 자원이 부족한 국내의 경우 원전을 해체하는데 있어 부지 재이용 문제는 하나의 중요한 사안이지만, 아직까지 부지 재이용을 위한 구체적인 법적 부지해제기준이 마련되어 있지 않다. 따라서 본 연구에서는 부지해제를 위한 IAEA의 국제적 안전기준(Safety Guide No. WS-G-5.1) 및 국내 관련기준, 미국 유럽 등 선진국들의 부지해제 사례들을 분석하였으며, 이를 바탕으로 적절한 선량기준 및 국내 부지해제 기준 수립 시 고려해야하는 사항들을 제언하였다. 이는 원전 해체 후 부지 재이용을 위한 국내 부지해제 기준 수립을 위한 기초자료로 활용될 것으로 판단된다.

• 방사성폐기물학회지
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• 제17권3호
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• pp.299-311
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• 2019

최근 한국에서 원전해체는 중요한 이슈이다. 원전의 운영 시와 비교해볼 때, 원전 해체 시에는 방사성물질의 방출이 크지 않을 것으로 예상되지만, 주민은 항상 방사선피폭으로부터 보호되어야 한다. 이에 대한 효과적인 관리를 위해, 연간 방출관리치와 방출한도치를 원자력안전위원회 고시 및 일반인 선량한도 기준으로부터 유도하였다. 기체상 유출물에 의한 대기 확산 및 침적 인자는 신고리 발전소 기상탑에서 2008년부터 2010년까지 3년간 수집 된 기상자료를 토대로 XOQDOQ 컴퓨터 코드를 이용해서 평가하였다. 선량평가는 ENDOS-G 컴퓨터 코드를 사용하였다. 이 컴퓨터 코드를 이용하여 기체상 유출물의 연간 방출관리치 및 방출한도치를 평가한 결과, 핵종별로 차이가 있었는데, 이는 연령에 따른 방사선민감도의 차이에 기인한다고 할 수 있다. 본 평가 방법 및 결과는 향후 원전 해체 시 방사성유출물 관리에 중요한 정보를 제공할 수 있을 것으로 판단된다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(2)
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• pp.879-884
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• 1995

The results of performance assessment analyses have shown that the long-lived radionuclides such as I-129 control the potential individual dose impact to the public. I-129 is difficult-to-measure(DTM) in low-level waste because it is non-gamma emitting radionuclides and exists at extremely low concentrations in radioactive waste generated by nuclear reactors. In this study, computer modeling technique to predict release rate of I-129 is developed to provide another tools far performance assessment of land disposal facilities and characteristics of radwaste. Model suggested in this study will give conservative values of I-129 release rate far determination of radwaste characteristics. More detailed approach is implemented to account for release conditions of fuel source-nuclides. 1-131 concentration measured from reactor coolant and released fraction from tramp fuel have dominant roles in calculating release rate of I-129 with fuel defect conditions.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.184-189
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• 1997

A prompt fission gas release model incorporating the resistance to gas flow in the gap was developed and the effects of gap resistance and failure location on prompt fission gas release from the cladding breach were assessed. The process of prompt fission gas release from the plenum and gap into the coolant was modeled in accordance with three major phenomena: (1) transient gas flow in the gap, (2) the growth of the fission gas bubble while it is still attached to the breach, and (3) the detachment of the fission gas bubble from the breach and mixing with the coolant. The cumulative mass release fraction by the present model was calculated for the case of Young-Gwang 3 & 4 nuclear fuel rod as a typical example. The results showed that the release behavior of prompt fission gas with time was different from the frictionless model which has frequently been used in a simplified approach, and that the location of cladding failure was another key factor for the prompt fission gas release process due to the resistance in the gap.

• Journal of Radiation Protection and Research
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• 제28권3호
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• pp.239-245
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• 2003

Every nuclear power plant measured concentrations of tritium in groundwater and surface water around the plants periodically. It was not easy to predict the tritium concentration only with these measurement data in case of various release scenarios. KAERI developed a new approach to find the relationship between the tritium release rate and tritium concentration in the environment. The approach was based upon a dynamic compartment model. In this paper the dynamic compartment model was modified to predict the tritium behavior more accurately. The mechanisms considered for the transfer of tritium between the compartments were evaporation, groundwater flow, infiltration, runoff, and hydrodynamic dispersion. Time dependent source terms of the compartment model were introduced to refine the release scenarios. Also, transfer coefficients between the compartments were obtained using realistic geographical data. In order to illustrate the model various release scenarios were developed, and the change of tritium concentration in groundwater and surface water around the nuclear power plants was estimated.

• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1098-1108
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• 2019

Korea's first commercial nuclear power plant at Kori site was permanently shut down in 2017 and is currently in transition stage. Preparatory activities for decommissioning such as historical site assessment, characterization, and dismantling design are being actively carried out for successful D&D (Dismantling and Decontamination) at Kori site. The ultimate goal of decommissioning will be to ensure the safety of workers and residents that may arise during the decommissioning of nuclear facilities and, thereby finally returning the site to its original status in accordance with the release criteria. Upon completion of decommissioning, the resident's safety at a site released will be assessed from the evaluation of dose caused by radionuclides expected to be present or detected at the site. Although the U.S. commercial nuclear power plants with decommissioning experience use different site release criteria, most of them are 0.25 mSv/y. In Korea, both the unrestricted and restricted release criteria have been set to 0.1 mSv/y by the Nuclear Safety and Security Commission. However, since the dose is difficult to measure, measurable concentration guideline levels for residual radionuclides that result in dose equivalent to the site release criteria should be derived. For this derivation, site reuse scenario, selection of potential radionuclides, and systematic methodology should be developed in planning stage of Kori site decommissioning. In this paper, for calculation of a preliminary site-specific Derived Concentration Guideline Levels (DCGLs) for the Nuclear Power Plant site, a novel approach has been developed which can fully reflect practical reuse plans of the Kori site by taking into account multiple site reuse scenarios sequentially, thereby striking a remarkable distinction with conventional approaches which considers only a single site scenario.