Development of a method to lower recontamination after chemical decontamination by depositing Pt nano particles: (II) consideration of the Pt effect on oxide composition |
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| Authors: | Tsuyoshi Ito Hideyuki Hosokawa Toru Kawasaki Yukie Ishizawa Kenji Inaba Nozomu Hatakeyama |
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| Affiliation: | 1. Center for Technology Innovation-Energy, Hitachi Ltd., Hitachi-shi, Japan;2. Hitachi Works, Hitachi-GE Nuclear Energy Ltd., Hitachi-shi, Japan;3. New Industry Creation Hatchery Center, Tohoku University, Sendai, Japan |
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| Abstract: | The Pt coating (Pt-C) process has been developed to lower the recontamination by 60Co which was incorporated in oxides on piping surface after chemical decontamination. In order to determine the suppression mechanism of 60Co deposition by Pt-C, it is important to investigate the formation of oxide film 60Co deposition behavior on oxide with Pt-C specimens. In this paper, we observed the composition change of oxide after a 60Co deposition test under the hydrogen water chemistry condition, and considered the 60Co deposition behavior on oxide for Pt-C specimens. The Ni and Co metal concentrations in oxide were dramatically changed by Pt-C process. The Ni metal concentrations in oxide for specimens with and without the Pt-C process were 11.2% and 18.0%, respectively. On the other hand, the Co metal concentrations in oxide for specimens with and without the Pt-C process were 1.2% and 0.2%, respectively. This composition change of the oxides indicated that 60Co incorporation for the Pt-C specimens was suppressed by replacing 60Co with Ni. We concluded that the Ni2+ ions were incorporated into the 8a site of the oxide spinel structure instead of Co2+ ions due to the effect of the conversion deposition energy. |
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| Keywords: | Boiling water reactor chemical decontamination recontamination primary loop recirculation stainless steel hydrogen water chemistry |
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