• Title/Summary/Keyword: Nuclear waste

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In-situ Measurements of Time-dependent Rock Deformations at the Waste Isolation Pilot Plant in USA (미국 Waste Isolation Pilot Plant에서의 시간변동 거동 계측)

  • Sangki Kwon;Chul-Hyung Kang;Jongwon Choi
    • Tunnel and Underground Space
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    • v.9 no.3
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    • pp.175-184
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    • 1999
  • Systematic measurements in the field are the key component in the design process to ensure that optimal and safe designs result. The instruments installed at the Waste Isolation Pilot Plant, a underground nuclear waste repository in U.S., for measuring rock deformation was reviewed. Also discussions about installation and measurement for better understanding the complex time-dependent deformational behavior of underground excavation were made.

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Image Reconstruction Techniques for Radioactive Waste Assay by Tomographic Gamma Scanning Method

  • Zhang Quanhu;Kim Ki-Hong;Hong Kwon-Pyo
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.11b
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    • pp.126-140
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    • 2005
  • The tomographic gamma scanner (TGS) method, a further of extension of segmented gamma scanner (SGS), is most accurate and precise for assaying heterogeneous drummed nuclear radioactive waste; it is widely used in nuclear power plants and radioactive waste storages and disposal sites. The transmission and emission images are reconstructed by image reconstruction techniques. In the paper, the principle of TGS is introduced; image reconstruction techniques are discussed as well; finally, it is demonstrated that TGS method performance.

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Characteristics of Cement Solidification of Metal Hydroxide Waste

  • Koo, Dae-Seo;Sung, Hyun-Hee;Kim, Seung-Soo;Kim, Gye-Nam;Choi, Jong-Won
    • Nuclear Engineering and Technology
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    • v.49 no.1
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    • pp.165-171
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    • 2017
  • To perform the permanent disposal of metal hydroxide waste from electro-kinetic decontamination, it is necessary to secure the technology for its solidification. The integrity tests on the fabricated solidification should also meet the criteria of the Korea Radioactive Waste Agency. We carried out the solidification of metal hydroxide waste using cement solidification. The integrity tests such as the compressive strength, immersion, leach, and irradiation tests on the fabricated cement solidifications were performed. It was also confirmed that these requirements of the criteria of Korea Radioactive Waste Agency on these cement solidifications were met. The microstructures of all the cement solidifications were analyzed and discussed.

The Effects of pH and Buffer Materials on the Leaching of Simulated Waste Glass

  • Kim, S.S.;Kim, J.G.;Kim, J.S.;Chun, K.S.;Lee, G.H.
    • Nuclear Engineering and Technology
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    • v.30 no.1
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    • pp.1-7
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    • 1998
  • Effects of pH, bentonite and Portland cement on the leaching of the simulated waste glass were investigated. The simulated waste glass showed the low leach rate in the neutral pH region, while the leach rate in both acidic and alkaline regions increased. Addition of bentonite to the leachant enhanced the leaching of the waste glass. When the waste glass was leached at 72$^{\circ}C$ for 36 days in the ground water with gel state Na-bentonite, approximately 2.2${\mu}{\textrm}{m}$ of the surface was corroded out and the large amount of Ti, Nd, and Zr was observed on the surface. The amount of B leached from the simulated waste glass in the presence of domestic bentonite was about three times higher than that in the presence of Aldrich bentonite as well as Portland cement.

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WASTE CLASSIFICATION OF 17×17 KOFA SPENT FUEL ASSEMBLY HARDWARE

  • Cho, Dong-Keun;Kook, Dong-Hak;Choi, Jong-Won;Choi, Heui-Joo
    • Nuclear Engineering and Technology
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    • v.43 no.2
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    • pp.149-158
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    • 2011
  • Metal waste generated from the pyroprocessing of 10 MtU of spent fuel was classified by comparing the specific activity of a relevant radionuclide with the limit value of the specific activity specified in the Korean acceptance criteria for a lowand intermediate-level waste repository. A Korean Optimized Fuel Assembly design with a 17${\times}$17 array, an initial enrichment of 4.5 weight-percent, discharge burn-up of 55 GWD/MtU, and a 10-year cooling time was considered. Initially, the mass and volume of each structural component of the assembly were calculated in detail, and a source term analysis was subsequently performed using ORIGEN-S for these components. An activation cross-section library generated by the KENO-VI/ORIGEN-S module was utilized for top-end and bottom-end pieces. As a result, an Inconel grid plate, a SUS plenum spring, a SUS guide tube subpart, SUS top-end and bottom-end pieces, and an Inconel top-end leaf spring were determined to be unacceptable for the Gyeongju low- and intermediate-level waste repository, as these waste products exceeded the acceptance criteria. In contrast, a Zircaloy grid plate and guide tube can be placed in the Gyeongju repository. Non-contaminated Zircaloy cladding occupying 76% of the metal waste was found to have a lower level of specific activity than the limit value. However, Zircaloy cladding contaminated by fission products and actinides during the decladding process of pyroprocessing was revealed to have 52 and 2 times higher specific activity levels than the limit values for alpha and $^{90}Sr$, respectively. Finally, it was found that 88.7% of the metal waste from the 17${\times}$17 Korean Optimized Fuel Assembly design should be disposed of in a deep geological repository. Therefore, it can be summarized that separation technology with a higher decontamination factor for transuranics and strontium should be developed for the efficient management of metal waste resulting from pyroprocessing.

A Numerical analysis of Underground Repository Cavern in Korean Crystalline rocks (우리나라 결정질암내 동굴처분장에 대한 수치해석)

  • 윤건신
    • The Journal of Engineering Geology
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    • v.1 no.1
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    • pp.68-84
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    • 1991
  • A numerical analysis using Universal Distinct Element Code program for the nuclear waste disposal cavern has been performed for a typical Korean crystalline rock condition with same geometry of Swedish low and intermediate nuclear waste disposal repository(S.F.R). The stress concentration, displacement and safety factor for the typical single cross section of cavern, 5 caverns and a silo are analyzed.

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