• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.1
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• pp.60-67
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• 2004

The exposure dose form recycling of a large amount of the steel scrap from the KRR-1＆2 decommissioning activities was evaluated, and also the clearance level(draft) was derived. The maximum individual dose and collective dose were evaluated by modifying internal dose conversion factor which was based on the concept of effective dose in ICRP 60, applied to the RESRAD-RECYCLE ver 3.06 computing code, IAEA Safety Series 111-P-1.1 and NUREG-1640 as the assessment tool. The result of assessment for individual dose and collective dose is 23.9 $\mu$Sv per year and 0.11 man$.$Sv per year respectively. The clearance levels were ultimately determined by extracting the most conservative value form the results of the generic assessment and specific assessment methodologies. The result of clearance level for radionuclides( $Co^{60}$ , C $s^{l37}$) is less than 1.14${\times}$10$^{-1}$ Bq/g to comply with the clearance criterion(maximum individual dose : 10 $\mu$Sv per year, collective dose : 1 man$.$Sv per year) provided for Korea Atomic Energy Act and relevant regulations.s.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.129-134
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• 2002

상업용 원자력 발전소와 연구용 원자로, 재처리시설 또는 원자력 관련 연구시설 등은 일반적으로 한계수명의 도달, 정치 경제적 사유 또는 안전성 둥의 이유로 폐지조치 하게 된다. 현재 세계적으로 80여기 이상의 발전소와 수백 개의 연구시설, 연구로 및 재처리 시설 등이 폐로 중에 있거나 대기중이다.(중략)

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1281-1282
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.1275-1276
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.249-250
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.205-206
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.836-837
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• 2005

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.198-201
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• 2001

Porous structures of aluminum foam have been studied by using return aluminum scrap. The apparent foam shape, foam height, density, pore size and their distributions in various section areas of the experimental samples have been investigated. The sample have been cast into metallic mold, using aluminum foam prepared from a precursor based on pure Al ingot and return aluminum scrap mixed with various amounts of 1-2wt% increasing viscosity and foam agent materials. The process provides for flexibility in design of foam structures via relatively easy control over the amount of hydrogen evolution and the drainage processes which occur during foam formation. This is facilitated by manipulating parameters such as the foaming agent, thermal histories during solidification and mix melt viscosities. A metal for producing the foamed are decomposing a foaming agent in a molten metal such that there is an initial and a subsequent expansion due to foaming agent. It has been found that the Al porous foaming with variation amount of 1∼2wt% foam agent and at 2min holding time, which melting temperature has appeared homogeneous pore size at 650∼700$^{\circ}C$. The compression strength were 10-13 kg/min at 125ppi, and increased by higher pore density. The acoustical performance of the panel made with the foamed aluminum is considerably improved; its absorption coefficient shows NRC 0.6-0.8. It has been found that the Al foam is very preferable for the compactness of the thermal system.

• Journal of the Korean Society of Safety
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• v.37 no.4
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• pp.129-138
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• 2022

A new method for injecting cooling water into the Korean research reactor (KRR) in the event of beam tube rupture is proposed in this paper. Moreover, the research evaluates the risk to the reactor core in terms of core damage frequency (CDF). The proposed method maintains the cooling water in the chimney at a certain level in the tank to prevent nuclear fuel damage solely by gravitational coolant feeding from the emergency water supply system (EWSS). This technique does not require sump recirculation operations described in the current procedure for resolving beam tube accidents. The reduction in the risk to the core in the event of beam tube rupture that can be achieved by the proposed change in the cooling water injection design is quantified as follows. 1) The total CDF of the KRR for the proposed design change is approximately 4.17E-06/yr, which is 8.4% lower than the CDF of the current design (4.55E-06/yr). 2) The CDF for beam tube rupture is 7.10E-08/yr, which represents an 84.1% decrease compared with that of the current design (4.49E-07/yr). In addition to this quantitative reduction in risk, the modified cooling water injection design maintains a supply of pure coolant to the EWSS tank. This means that the reactor does not require decontamination after an accident. Thermal hydraulic analysis proves that the water level in the reactor pool does not cause damage to the nuclear fuel cladding after beam tube rupture. This is because the amount of water in the chimney can be regulated by the EWSS function. The EWSS supplies emergency water to the reactor core to compensate for the evaporation of coolant in the core, thus allowing water to cover the fuel assemblies in the reactor core over a sufficient amount of time.

• Nuclear Engineering and Technology
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• v.34 no.6
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• pp.610-618
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• 2002

A study of the conceptual data modeling to realize the decommissioning database on the HRR-1&2 was carried out. In this study, the current state of the abroad decommissioning database was investigated to make a reference of the database. A scope of the construction of decommissioning database has been set up based on user requirements. Then, a theory of the database construction was established and a scheme on the decommissioning information was classified . The facility information, work information, radioactive waste information, and radiological information dealing with the decommissioning database were extracted through interviews with an expert group and also decided upon the system configuration of the decommissioning database. A code which is composed of 17 bit was produced considering the construction, scheme and information. The results of the conceptual data modeling and the classification scheme will be used as basic data to create a prototype design of the decommissioning database.