• Title/Summary/Keyword: 콘크리트 방사화

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Radioactivation Analysis of Concrete Shielding Wall of Cyclotron Room Using Monte Carlo Simulation (PET 사이클로트론 가동에 따른 콘크리트 차폐벽의 방사화)

  • Jang, Donggun;Lee, Dongyeon;Kim, Junghoon
    • Journal of the Korean Society of Radiology
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    • v.11 no.5
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    • pp.335-341
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    • 2017

  • Cyclotron is a device that accelerates positrons or neutrons, and is used as a facility for making radioactive drugs having short half-lives. Such radioactive drugs are used for positron emission tomography (PET), which is a medical apparatus. In order to make radioactive drugs from a cyclotron, a nuclear reaction must occur between accelerated positrons and a target. After the reaction, unncessary neutrons are produced. In the present study, radioactivation generated from the collisions between the concrete shielding wall and the positrons and neutrons produced from the cyclotron is investigated. We tracked radioactivated radioactive isotopes by conducting experiments using FLUKA, a type of Monte Carlo simulation. The properties of the concrete shielding wall were comparatively analyzed using materials containing impurities at ppm level and materials that do not contain impurities. The generated radioactivated nuclear species were comparatively analyzed based on the exposure dose affecting human body as a criterion, through RESRAD-Build. The results of experiments showed that the material containing impurities produced a total of 14 radioactive isotopes, and $^{60}Co$(72.50%), $^{134}Cs$(16.75%), $^{54}Mn$(5.60%), $^{152}Eu$(4.08%), $^{154}Eu$(1.07%) accounted for 99.9% of the total dose according to the analysis having the exposure dose affecting human body as criterion. The $^{60}Co$ nuclear species showed the greatest risk of radiation exposure. The material that did not contain impurities produced a total of five nuclear species. Among the five nuclear species, 54Mn accounted for 99.9% of the exposure dose. There is a possibility that Cobalt can be generated by inducive nuclear reaction of positrons through the radioactivation process of $^{56}Fe$ instead of impurities. However, there was no radioactivation because only few positrons reached the concrete wall. The results of comparative analysis on exposure dose with respect to the presence of impurities indicated that the presence of impurities caused approximately 98% higher exposure dose. From this result, the main cause of radioactivation was identified as the small ppm-level amount of impurities.

  • https://doi.org/10.7742/jksr.2017.11.5.335 인용 PDF KSCI

Probability-Based Performance Prediction of the Nuclear Contaminated Bio-Logical Shield Concrete Walls (원전 방사화 콘크리트 차폐벽의 확률 기반 성능변화 예측)

  • Kwon, Ki-Hyon;Kim, Do-Gyeum;Lee, Ho-Jae;Seo, Eun-A;Lee, Jang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.4
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    • pp.316-322
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    • 2019

  • A probabilistic approach considering uncertainties was employed to investigate the effects on the material characteristics and strength of nuclear bio-logical shield concrete walls, when exposed to long-term radiation during the entire service life. Time-dependent compressive and tensile strengths were estimated by conducting the neutron fluence analysis. For the contaminated concrete, individual compressive and tensile failure probabilities can be possibly evaluated by not only establishing limit-state function withthe predefined critical values but also performing Monte Carlo Simulation. Nuclear power plant types similar to the Kori Unit 1, which was shut off permanently in 2017 after the 40-year operation, were herein selected for an illustrative purpose. Consequently, the probability-based performance assessment and prediction of contaminated concrete walls were well demonstrated.

  • https://doi.org/10.14190/JRCR.2019.7.4.316 인용 PDF KSCI

Spatial Distributions of $^3H$ and $^{14}C$ in the Shielding Concrete of KRR-2 (연구로 2호기 수조 콘크리트의 $^3H$ 및 $^{14}C$ 공간분포)

  • Hong, Sang-Bum;Kim, Hee-Reyoung;Chung, Kun-Ho;Kang, Mun-Ja;Jeong, Gyeong-Hwan;Chung, Un-Soo;Park, Jin-Ho
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.4 no.4
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    • pp.329-334
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    • 2006

  • The depth distributions of total $^3H$ and $^{14}C$ activities were characterized for the activated shielding concrete from a decommissioning of KRR-2 using the commercially available tube furnace and a liquid scintillation counter. The correlation of measurement results between $^3H,\;^{14}C$ and gammer emitter was evaluated to apply for estimating radionuclide inventory of the concrete waste generated from decommissioning KRR-2. The detection limits for $^3H$ and $^{14}C$ are 0.048 and 0.028 Bq/g respectively. The specific activities of the $^3H$ and $^{14}C$ tend to decrease exponentially as the depth of the concrete becomes deeper from the surface. In addition, the $^3H$ and $^{14}C$ activities were in good correlation with the $^{60}CO$ activities analysed for the shielding concrete of KRR-2.

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