• Title/Summary/Keyword: nuclear-decommissioning facilities

Search Result 87, Processing Time 0.028 seconds

Parametric Study for Structural Reinforcement Methods of Disposal Container for NPP Decommissioning Radioactive Waste

  • Hyungoo Kang;Hoseog Dho;Jongmin Lim;Yeseul Cho;Chunhyung Cho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.21 no.3
    • /
    • pp.329-345
    • /
    • 2023
  • This paper described a method for analyzing the structural performance of a metal container used for disposing radioactive waste generated during the decommissioning of a nuclear power plant, and numerical analysis results of a method for reinforcing the container. The containers to be analyzed were those that can be used in near-surface and landfill disposal facilities scheduled to be operated at the Gyeongju radioactive waste disposal facility. Structural reinforcement of the container was performed by lattice reinforcement, column reinforcement, and bottom plate reinforcement. Accordingly, a total of 14 reinforcement cases were modeled. The external force causing damage to the container was set equivalent to the impact of a 9-m fall, accounting for the height of the vault at the near-surface disposal facility. The reinforcement methods with a high contribution to the structural performance of the container were concluded to be lattice and column reinforcements.

Monte Carlo simulation for verification of nonparametric tests used in final status surveys of MARSSIM at decommissioning of nuclear facilities

  • Sohn, Wook;Hong, Eun-hee
    • Nuclear Engineering and Technology
    • /
    • v.53 no.5
    • /
    • pp.1664-1675
    • /
    • 2021
  • In order to verify the statistical performance of the nonparametric tests used in the MARSSIM approach, all plausible contamination distribution types that can be encountered in a survey area should be investigated. As the first of such investigations, this study aims to perform the verification for normal distribution of the contamination in a survey area by simulating the collection of random samples from it through the Monte Carlo simulation. The results of the simulations conducted for a total of 81 simulation cases showed that Sign test and WRS test both exhibited an excellent statistical performance: 100% for the former and 98.8% for the latter. Therefore, in final status surveys of the MARSSIM approach, a high statistical performance can be expected in applying the nonparametric hypothesis tests to survey areas whose net contamination can be assumed to be normally distributed.

A Mathematical Model to Evaluate the Radiological Risks for the Reuse of Decommissioning Site (원자력시설 해체부지의 재이용을 위한 방사선학적 리스크 평가모델)

  • Cheong, Jae-Hak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.4 no.4
    • /
    • pp.353-363
    • /
    • 2006
  • In order to evaluate the potential radiological risks for the reuse of the site after decommissioning of nuclear facilities, a mathematical model was developed and materialized into the Microsoft $Excel{\circledR}$ spreadsheets frame. A set of input parameter values was proposed, which is useful in the preliminary risk screening step before the detailed evaluation with the site-specific data. It appeared that the screening levels calculated by the present model was agreed with the derived concentration guideline limits resulted from RESRAD Ver.6.2 and the German dose criteria for releasing a nuclear site from regulatory control.

  • PDF

A preparation plan proposal of nuclear power plant decommissioning radioactive waste characterization report (원자력발전소 해체 방사성폐기물 특성보고서 작성 방안 제안)

  • Kim, Chang Lak;Lee, Sun Kee;Kim, Heon;Park, Hae Soo;Sung, Suk Hyun;Kong, Chang Sig
    • Journal of the Korean Society of Systems Engineering
    • /
    • v.17 no.1
    • /
    • pp.76-84
    • /
    • 2021
  • Radioactive waste generated from nuclear power plant decommissioning shall be strictly managed so that radioactive materials above the allowable limit are not leaked into the environment. Radioactive wastes shall be classified and treated for management based on characteristics such as the type of waste, physicochemical properties, nuclide concentration and radioactivity. Waste characterization report shall be prepared and submitted to the disposal facility operator to ensure that the treated waste is suitable for disposal. The disposal facility operator shall review the waste Characterization report and visit the nuclear power plant decommissioning site to ensure that the wastes are processed step by step according to the plan. The waste Characterization report may be used as input data to evaluate disposal facility safety. Domestic and foreign data are collected and reviewed to confirm the entire processes from waste generation to delivery. This paper proposes the method to prepare the waste Characterization report which contains data and information on waste characteristics, treatment facilities & method and packaging method & container.

Comprehensive Assessment on Risk Factors using Fuzzy Inference in Decommissioning Process (퍼지추론을 이용한 해체공정 중 리스크 요인의 통합 평가)

  • Lim, Hyeon Kyo;Kim, Hyunjung
    • Journal of the Korean Society of Safety
    • /
    • v.29 no.4
    • /
    • pp.184-190
    • /
    • 2014
  • Decommissioning process of nuclear facilities consist of a sequence of problem solving activities, because there may exist not only working environments contaminated by radiological exposure but also industrial hazards such as fire, explosions, toxic materials, and electrical and physical hazards. Therefore, not a few countries in the world have been trying to develop appropriate counter techniques in order to guarantee safety and efficiency of the process. In spite of that, there still exists neither domestic nor international standard. Unfortunately, however, there are few workers who experienced decommissioning operations a lot in the past. As a solution, it is quite necessary to utilize experts' opinions for risk assessment in decommissioning process. As for an individual hazard factor, risk assessment techniques are getting known to industrial workers with advance of safety technology, but the way how to integrate those results is not yet. This paper aimed to find out an appropriate technique to integrate individual risk assessment results from the viewpoint of experts. Thus, on one hand the whole risk assessment activity for decommissioning operations was modeled as a sequence of individual risk assessment steps which can be classified into two activities, decontamination and dismantling, and on the other, a risk assessment structure was introduced. The whole model was inferred with Fuzzy theory and techniques, and a numerical example was appended for comprehension.