Hostname: page-component-7479d7b7d-k7p5g Total loading time: 0 Render date: 2024-07-11T02:03:47.001Z Has data issue: false hasContentIssue false
  • English
  • Français

Investigation of C-14 in the CRUD collected on the coolant filter of commercial PWR (I) - thermal decomposition characteristics and C-14 release behavior under various gas atmospheres

Published online by Cambridge University Press:  16 January 2018

Kenichiro KINO ,
Akira SAKASHITA ,
Kotaro NAKATA ,
Shintaro TSUJI  and
Toshikazu WAKI
Kenichiro KINO*
Affiliation:
Nuclear Development Corporation, 622-12 Funaishikawa, Tokaimura, Ibaraki319-1111, JAPAN.
Akira SAKASHITA
Affiliation:
Mitsubishi Heavy Industries, LTD 16-5, Konan 2-Choume, Minato-ku Tokyo108-8215, JAPAN
Kotaro NAKATA
Affiliation:
Central Research Institute of Electric Power Industry, 1646 Abiko, Abikoshi, Chiba270-1194, JAPAN.
Shintaro TSUJI
Affiliation:
The KANSAI Electric Power Co., INC, 3-6-16 Nakanoshima Kita-ku Osaka-shi, Osaka530-8270JAPAN
Toshikazu WAKI
Affiliation:
The KANSAI Electric Power Co., INC, 3-6-16 Nakanoshima Kita-ku Osaka-shi, Osaka530-8270JAPAN
*
*(Email: kenichiro_kino@ndc.mhi.co.jp)
Get access

Abstract

In the safety assessment of a radioactive waste disposal, it is extremely important to assess the migration behavior of long-half-life radionuclides in the disposal environment. The migration behavior in the disposal environment for a radionuclide varies with the chemical form of the nuclide. In particular, C-14 has various chemical forms, and its migration behavior in the disposal environment substantially varies with the chemical forms. It has been reported that hardly soluble C-14 is generated in PWRs. However, the chemical form of this hardly soluble C-14 is little known. In this study, the thermal decomposition behavior of particles containing C-14 and the mass spectra of gases released through thermal decomposition were analyzed in order to examine the chemical form of C-14 generated in PWRs. In this study, the gases released during the thermogravimetric (TG) analysis were partially oxidized to CO2, trapped in an alkaline solution and analysed for C-14. Another part of the gas was analysed directly by mass spectrometry (MS). The residues obtained after TG analysis were also analysed for C-14 by oxidizing the residue to CO2, trapping the CO2 in alkaline solutions and analysing C-14 by LSC. During TG-analysis in inert gas (He) atmosphere, about 90% of C-14 was found in residue, while when air was used during TG-analysis, no C-14 could be detected in residue. From the MS-analysis of species released during TG-analysis in inert gas, fragments regarded as originating from ion-exchange resins were detected in released gases. Based on this result, it was found that while substances originating from ion-exchange resin were present in radioactive particles generated in a PWR, the main part of C-14 was contained in the residue after heating in the form of thermally stable substances, easy to be oxidized by air at high temperature. It was not possible to determine their exact chemical composition in this work but also, In addition, sorption of insoluble C-14 to cementitious materials was preliminarily examined. As a results, the concentration of insoluble C-14 decreased greatly in 7 days. That means insoluble C-14 tended not to stay in water. Elucidation of the sorption mechanism in the disposal environment of these C-14 is also a future task.

Keywords

thermogravimetric analysis (TGA)mass spectroscopydifferential thermal analysis (DTA)absorption
Type
Articles
Information
MRS Advances , Volume 3 , Issue 19: Scientific Basis for Nuclear Waste Management XLI , 2018 , pp. 1051 - 1058
Check for updates
Copyright
Copyright © Materials Research Society 2018 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

MUKAI, S., SAIGUSA, M., SAKASHITA, A., HORIKAWA, Y., and HIGUCHI, N., "Characterization of C-14 in PWR Radioactive Waste" J. Power Energy Systems 215–220(2008).Google Scholar
Arthur Byers, W., DeVito, Rachel L., and Correal-Pulver, Olga A., "Evaluation of Fuel Cladding Corrosion and Corrosion Product Deposits from Callaway Cycle 14 -Results of Poolside Measurements Following Two Cycles of Zinc Addition-, 1013425, p5–10, EPRI(2006).Google Scholar
NAKATA, K., HIRONAGA, M., MINATO, D., KINO, K., SAKASHITA, A, TAKAO, K., and SAKAKIHARA, T., " Investigation of C-14 in the CRUD collected on the coolant filter for safety disposal of radioactive waste containing C-14 (II) – Chemical alteration of ion exchange resin under simulated condition in primary coolant of PWR – presented at Scientific Basis for Nuclear Waste Management, Sydney, 2017 "to be published"Google Scholar
SASOH, M., "Investigations of Distribution Coefficients for C-14 from Activated Metal" NAGRA NIB 04–03 p85 (2004).Google Scholar