• Title/Summary/Keyword: Radioactive

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Evaluation of Exposure Dose and Working Hours for Near Surface Disposal Facility

  • Yeseul Cho;Hoseog Dho;Hyungoo Kang;Chunhyung Cho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.20 no.4
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    • pp.511-521
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    • 2022

  • Decommissioning of nuclear power plants generates a large amount of radioactive waste in a short period. Moreover, Radioactive waste has various forms including a large volumes of metal, concrete, and solid waste. The disposal of decommissioning waste using 200 L drums is inefficient in terms of economics, work efficiency, and radiation safety. Therefore, The Korea Radioactive Waste Agency is developing large containers for the packaging, transportation, and disposal of decommissioning waste. Assessing disposability considering the characteristics of the radioactive waste and facility, convenience of operation, and safety of workers is necessary. In this study, the exposure dose rate of workers during the disposal of new containers was evaluated using Monte Carlo N-Particle Transport code. Six normal and four abnormal scenarios were derived for the assessment of the dose rate in a near surface disposal facility operation. The results showed that the calculated dose rates in all normal scenarios were lower than the direct exposure dose limitation of workers in the safety analysis report. In abnormal scenarios, the work hours with dose rates below 20 mSv·y-1 were calculated. The results of this study will be useful in establishing the optimal radiation work conditions.

  • https://doi.org/10.7733/jnfcwt.2022.039 인용 PDF KSCI

Efficient Computation of Radioactive Decay with Graph Algorithms

  • Yoo, Tae-Sic
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.1
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    • pp.19-29
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    • 2020

  • This paper gives two graph-based algorithms for radioactive decay computation. The first algorithm identifies the connected components of the graph induced from the given radioactive decay dynamics to reduce the size of the problem. The solutions are derived over the precalculated connected components, respectively and independently. The second algorithm utilizes acyclic structure of radioactive decay dynamics. The algorithm evaluates the reachable vertices of the induced system graph from the initially activated vertices and finds the minimal set of starting vertices populating the entire reachable vertices. Then, the decay calculations are performed over the reachable vertices from the identified minimal starting vertices, respectively, with the partitioned initial value over the reachable vertices. Formal arguments are given to show that the proposed graph inspired divide and conquer calculation methods perform the intended radioactive decay calculation. Empirical efforts comparing the proposed radioactive decay calculation algorithms are presented.

  • https://doi.org/10.7733/jnfcwt.2020.18.1.19 인용 PDF KSCI

The Study on the Way of Radioactive Waste Disposal in China

  • Keyan Teng;Hao Peng;Caixia Lv;Han Wu
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.20 no.4
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    • pp.533-540
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    • 2022

  • Because of the massive development of nuclear power plants in China in recent years, China is facing the challenge of radioactive waste disposal. China has established complete regulatory requirements for radioactive waste disposal, but it also has encountered problems and challenges in low-level radioactive waste disposal in terms of management, selection of disposal facility sites, and implementation of a site selection plan. Three low-level radioactive waste disposal facilities that have been operated in China are described, and their activity limits, locations, and capacities are also outlined. The connotations of "regional" and "centralized" disposal policies are discussed in light of the characteristics of the radioactive waste. The characteristics and advantages of the regional and centralized disposal policies are compared. It is concluded that the regional disposal policy adopted in 1992 can no longer meet the current disposal needs, and China should adopt a combination of the two disposal policies to solve the problem of radioactive waste disposal.

  • https://doi.org/10.7733/jnfcwt.2022.042 인용 PDF KSCI