• Title/Summary/Keyword: CRUD

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A Study on the Removal Method of Radioactive Corrosion Product using its Magnetic Property (방사성 부식생성물의 자기적 성질을 이용한 제거방법에 대한 연구)

  • 송민철;공태영;이건재
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.1 no.1
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    • pp.73-79
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    • 2003
  • In a pressurized water reactor, radioactive corrosion products (CRUD) in primary coolant system are one of the major sources for the occupational radiation exposure of the personnel in a nuclear power plant. Through the recent trend of long term fuel cycle in a nuclear power Plant, radioactive corrosion products deposited in reactor core for a long time are also the cause of Axial Offset Anomaly (AOA) having m effect on reactor power by the hideout of boron. CRUD consist primarily of magnetite, nickel ferrite, cobalt ferrite, and so on. They have the characteristic of strong magnetism. Therefore it is performed the conceptual design to develop the filter which removes the CRUD by magnetic field that is generated by an arrangement of permanent and electric magnets. Contrary to the conventional filter, the proposed filter does not interrupt the fluid flow, so there is little pressure drop and it can be used continuously. It is expected to be applied as one of the technologies for removal of the CRUB.

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Evaluation of Core Residence Time of Fuel Cruds from Hanul Unit 1 Cycle 17 (한울1호기 17주기 연료 크러드의 노내 체류시간 평가)

  • Lee, Doo Ho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.12 no.3
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    • pp.211-216
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    • 2014
  • Corrosion products are released to the primary coolant in the corrosion process of structural materials. They are deposited on fuel surfaces and activated on exposure to a neutron flux with formation of radionuclides that can become incorporated into out-of-core surface films. To get a clear understanding of activated crud formation process, the specific activity and core residence time of fuel cruds was calculated as a function of exposure time to the core neutron flux on the assumption that parent nuclide is being deposited continuously. Fuel cruds were sampled in the fuel scraping campaign from Hanul Unit 1 Cycle 17 and analyzed for elemental concentration and radioisotope activity.

경수로 원자로 냉각재 CRUD 대표시료 채취 기술에 관한 고찰

  • Kim, Min-Jae;Kim, Jong-Bin;Gang, Deok-Won;Park, Jong-Seok
    • 대한방사선방어학회:학술대회논문집
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    • 2009.04a
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    • pp.254-255
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    • 2009
  • 국내 경수로 원전의 경우, 원전의 효율적, 경제적 운영차원에서 장주기 운전으로 패턴을 바뀌면서 핵연료봉 표면상에 크러드(crud)의 침적량은 점점 증가하는 경향을 나타내고 있다. 이러한 경향은 원자로의 출력 제어와 직결되면서 이에 대한 문제 해결을 위한 대표성이 있는 시료의 채취와 재현성이 있는 부식 생성물의 측정이 요구되어져 왔다. 원자로 계통 내에서 부식생성물의 농도변화에 대한 평가, 특히 입자농도가 증가되어지면 축방향 출력편차(Axial Offset Anomaly, AOA)가 발생될 수 있는 위험에 노출되거나, 핵연료 교체를 위해 발전소 정지시(shut down) 부식생성물의 방출이 급격히 증가되는 것으로 나타났다. 특히 입자성을 띤 물질은 존재의 특성상 이들 물질에 대한 대표시료의 채취가 어려울 뿐 아니라 grab 채취로 인해, 분석결과에 대한 재현성이 낮으며 계통 선량율의 제어와 작업자 피폭관리에 많은 어려움이 뒤따르고 있어 선진 원전 운영국에서는 앞 다투어 대표시료를 채취 할 수 있는 capillary sampling 법이나 integrated sampling법을 적용해 오고 있다. 본 논문에서는 국내 경수로 원전에서 일반적으로 사용하고 있는 grab sampling 법에 대한 문제점 파악과 해외 원전에서 사용 중인 capillary sampling 법의 국내 적용 가능성에 대해 살펴보았다.

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Performance Evaluation and Optimal Operation Strategy of OpenDaylight Controller Cluster (오픈데이라이트 컨트롤러 클러스터 성능 분석 및 최적 운영 방안)

  • Kim, Taehong;Suh, Dongeun;Pack, Sangheon;Kim, Myung-Sup;Lim, Chang-Gyu;Park, Soomyung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.12
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    • pp.1801-1810
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    • 2016
  • The OpenDaylight controller has been receiving significant attention as one of the enabling open source framework for SDN, and this paper analyzes the architecture and procedure of OpenDaylight based controller cluster. The OpenDaylight controller cluster uses shard based distributed datastore and Raft algorithm to maintain consistency among controllers inside a cluster. The performance evaluation analyzes the leader re-election time as well as latencies of CRUD and Routed RPC according to cluster size, shard role, and sharding strategy, and we discuss the optimal operation strategy for OpenDaylight controller cluster.