• Title/Summary/Keyword: Nuclear Fuel Cladding

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Microstructure and Corrosion Behavior of Zr Alloys with Manufacturing Process (핵연료피복관용 Zr 합금의 제조공정에 따른 미세조직 및 부식거동)

  • Kim, H.G.;Choi, B.K.;Kim, K.T.;Kim, S.D.;Park, C.H.;Jeong, Y.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.18 no.5
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    • pp.288-296
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    • 2005
  • The corrosion behaviors of Zr-based alloys were very sensitive to their microstructures which were determined by manufacturing process. The specimens of Zr-based alloy named as HANA-4 for nuclear fuel cladding were investigated in order to get the optimized manufacturing process such as the intermediate annealing temperature and cold working steps after the ${\beta}$ quenching. From the microstructural analysis, cold worked microstructure of the samples was changed to the recrystallized microstructure by performed process. The corrosion behaviors of HANA-4 alloy were affected by the different manufacturing process. The ${\beta}$-Zr phase was formed in the matrix and the Nb concentration in the ${\beta}$-Zr phase was increased as progressing the manufacturing process. So, it was found that the corrosion rate of HANA-4 alloy was affected by the Nb concentration in the matrix.

Evaluation of SMUT Properties according to Nb Content in the Pickling Process of Nuclear Fuel Cladding Tube (핵연료 피복관의 산세 공정 시 Nb 함량에 따른 SMUT 특성)

  • Moon, Jong Han;Lee, Young Jun;Lee, Jin Hang;Hong, Jong Won;Lee, Jong Hyeon
    • Korean Journal of Materials Research
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    • v.29 no.8
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    • pp.483-490
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    • 2019
  • Currently, the Korean nuclear industry uses ZIRLO as material for nuclear fuel cladding(zirconium alloy). KEPCO Nuclear Fuel is in the process of developing a HANA alloy to enable domestic production of cladding. Cladding manufacture involves multistage heat treatments and pickling processes, the latter of which is vital for the removal of defects and impurities on the cladding surface. SMUT that forms on the cladding surface during such pickling process is a source of surface defects during heat treatment and post-treatment processes if not removed. This study analyzes ZIRLO, HANA-4, and HANA-6 alloy claddings to extensively study the SEM/EDS, XRD, and particle size characteristics of SMUT, which are second phase particles that are formed on the cladding surface during pickling processes. Using the analysis results, this study observes SMUT formation characteristics according to Nb concentration in Zr alloys during the washing process following the pickling process. In addition, this study observes SMUT removal characteristics on cladding surfaces according to concentrations of nitric acid and hydrofluoric acid in the acid solution.

Mechanical Integrity Evaluation on the Degraded Cladding Tube of Spent Nuclear Fuel Under Axial and Bending Loads During Transportation

  • Lee, Seong-Ki;Lee, Dong-Hyo;Park, Joon-Kyoo;Kim, Jae-Hoon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.4
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    • pp.491-501
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    • 2021
  • This paper aims to evaluate the mechanical integrity for Spent Nuclear Fuel (SNF) cladding under lateral loads during transportation. The evaluation process requires a conservative consideration of the degradation conditions of SNF cladding, especially the hydride effect, which reduces the ductility of the cladding. The dynamic forces occurring during the drop event are pinch force, axial force and bending moment. Among those forces, axial force and bending moment can induce transverse tearing of cladding. Our assessment of 14 × 14 PWR SNF was performed using finite element analysis considering SNF characteristics. We also considered the probabilistic procedures with a Monte Carlo method and a reliability evaluation. The evaluation results revealed that there was no probability of damage under normal conditions, and that under accident conditions the probability was small for transverse failure mode.