• Title/Summary/Keyword: Radioactive material

Search Result 454, Processing Time 0.037 seconds

A study on the effect of material impurity concentration on radioactive waste levels for plans for decommissioning of nuclear power plant

  • Gilyong Cha;Minhye Lee;Soonyoung Kim;Minchul Kim;Hyunmin Kim
    • Nuclear Engineering and Technology
    • /
    • v.55 no.7
    • /
    • pp.2489-2497
    • /
    • 2023
  • Co and Eu impurities in the SSCs are nuclides that dominantly influence the neutron-induced radioactive inventory in metal and concrete radwastes (radioactive wastes) during NPP decommission. The impurity concentrations provided by NUREG/CR-3474 were used for the practical range of Co and Eu impurity concentrations to be applied to the code calculations. Metal structures near the core were evaluated to be ILW (intermediate-level waste) for the whole range of Co impurity concentration, so the boundary line between ILW and LLW (low-level waste) has no change for the whole concentration range provided by NUREG/CR-3474. Also, the boundary line between VLLW (very low-level waste) and CW (clearance waste) in the concrete shield could alter a little depending on the Eu impurity concentration within the range provided by NUREG/CR-3474. From this work, it is found that the concentration of material impurities of SSCs gives no critical impact on determining radwaste levels.

Formulation on the Empirical Equation of the Cask Impact Forces by Dimensional Analysis (차원해석을 이용한 사용후 핵연료 수송용기의 충격력 실험식 공식화)

  • Kim Yong-Jae;Choi Young-Jin;Lee Young-Shin
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.18 no.3
    • /
    • pp.245-254
    • /
    • 2005
  • Radioactive material is used in the various fields. The numbers of transport for radioactive material have been gradually increased in both domestic and International regions. The safety of the cask should be secured to safely transport of radioactive material. The korean atomic law and the IAEA safety standards prescribe regulations lot the safe transport of radioactive material The cask for spent fuel is comprised of the body and the impact limiter. In this study, the empirical equation of the cask impact force is proposed based on the dimensional analysis. Using this empirical equation the characteristics of the impact limiter are analyzed. The results are also validated by comparing with the previous results of the impact area method and the finite element analysis. The present method can be used to predict the impact force of the cask.

An Influence Analysis on the Gap Space of an Engineered Barrier for an HLW Repository (고준위폐기물처분장 공학적방벽의 갭 공간이 미치는 영향 분석)

  • Yoon, Seok;Lee, Changsoo;Kim, Min-Jun
    • Journal of the Korean Geotechnical Society
    • /
    • v.37 no.4
    • /
    • pp.19-26
    • /
    • 2021
  • The high-level radioactive waste (HLW) produced from nuclear power plants is disposed in a rock-mass at a depth of hundreds meters below the ground level. Since HLW is very dangerous to human being, it must be disposed of safely by the engineered barrier system (EBS). The EBS consists of a disposal canister, backfill material, buffer material, and so on. When the components of EBS are installed, gaps inevitably exist not only between the rock-mass and buffer material but also between the canister and buffer material. The gap can reduce water-retarding capacity and heat release efficiency of the buffer material, so it is necessary to investigate properties of gap-filling materials and to analyze gap spacing effect. Furthermore, there has been few researches considering domestic disposal system compared to overseas researches. In this reason, this research derived the peak temperature of the bentonite buffer material considering domestic disposal system based on the numerical analysis. The gap between the canister and buffer material had a minor effect on the peak temperature of the bentonite buffer material, but there was 40% difference of the peak temperature of the bentonite buffer material because of the gap existence between the buffer material and rock mass.

DEPTH AND LAYOUT OPTIMIZATIONS OF A RADIOACTIVE WASTE REPOSITORY IN A DISCONTINUOUS ROCK MASS BASED ON A THERMOMECHANICAL MODEL

  • Kim, Jhin-Wung;Koh, Yong-Kwon;Bae, Dae-Seok;Choi, Jong-Won
    • Nuclear Engineering and Technology
    • /
    • v.40 no.5
    • /
    • pp.429-438
    • /
    • 2008
  • The objective of the present study is the depth and layout optimizations of a single layer, high level radioactive waste repository in a discontinuous rock mass with special joint set arrangements. A single layer repository model, considering variations in the repository depths, pitches, and tunnel spacings, is used to analyze the thermomechanical interaction behavior. It is assumed that the repository is constructed in saturated granite with joints; the PWR spent fuel in a disposal canister is installed in a deposition drift which is then sealed with compacted bentonite; and the backfill material is filled in the repository tunnel. The decay heat generated by the high level radioactive wastes governs the thermomechanical behavior of the near field rock mass of the repository. The temperature and displacement behavior of the repository is influenced more by the pitch variations than the tunnel spacing and repository depth. However, the stress behavior is influenced more by the repository depth variations than the pitch and tunnel spacing. For the final selection of the tunnel spacing, pitch, and repository depth, other aspects such as the nuclide migration through a groundwater flow path, construction costs, operation costs, and so on should be considered.