Ageing of a phosphate ceramic used to immobilize chloride-contaminated actinide waste

Metcalfe, Brian; Donald, Ian W.; Fong, Shirley K.; Gerrard, Lee A.; Strachan, Denis M.; Scheele, Randall D.

doi:10.1016/j.jnucmat.2008.12.035

Title: Ageing of a phosphate ceramic used to immobilize chloride-contaminated actinide waste

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Abstract

At AWE, we have developed a process for the immobilization of ILW waste containing a significant quantity of chloride with Ca₃(PO₄)₂ as the host material. Waste ions are incorporated into two phosphate-based phases, chlorapatite [Ca₅(PO₄)₃Cl] and spodiosite [Ca₂(PO₄)Cl]. Non-active trials performed at AWE with Sm as the actinide surrogate demonstrated the durability of these phases in aqueous solution. Trials of the process, in which actinide-doped materials were used, wer performed at PNNL where the waste form was found to be resistant to aqueous leaching. Initial leach trials conducted on ²³⁹Pu /²⁴¹Am loaded ceramic at 40°C/28 days gave normalized mass losses of 1.2 x 10^-5 g.m^-2 and 2.7 x 10^-3 g.m^-2 for Pu and Cl respectively. In order to assess the response of the phases to radiation-induced damage, accelerated ageing trials were performed on samples in which the ²³9Pu was replaced with ²³⁸Pu. No changes to the crystalline structure of the waste were detected in the XRD patterns after the samples had experienced an α radiation dose of 4 x 10¹⁸ g^-1. Leach trials showed that there was an increase in the P and Ca release rates but no change in the Pu release rate.

Authors:

Metcalfe, Brian ^[1]; Donald, Ian W. ^[1]; Fong, Shirley K. ^[1]; Gerrard, Lee A. ^[1]; Strachan, Denis M. ^[2]; Scheele, Randall D. ^[2]

AWE plc, Reading (United Kingdom)
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Publication Date:: Tue Mar 31 00:00:00 EDT 2009

Research Org.:: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 964613

Report Number(s):: PNNL-SA-60519
Journal ID: ISSN 0022-3115; JNUMAM; 830403000; TRN: US0903878

DOE Contract Number:: AC05-76RL01830

Resource Type:: Journal Article

Journal Name:: Journal of Nuclear Materials

Additional Journal Information:: Journal Volume: 385; Journal Issue: 2; Journal ID: ISSN 0022-3115

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ACTINIDES; AQUEOUS SOLUTIONS; CERAMICS; CHLORIDES; LEACHING; PHOSPHATES; RADIATION DOSES; WASTE FORMS; WASTES; X-RAY DIFFRACTION; plutonium immobilization; chloride immobilization; radiation-induced damage; waste management

Citation Formats


                    Metcalfe, Brian, Donald, Ian W., Fong, Shirley K., Gerrard, Lee A., Strachan, Denis M., and Scheele, Randall D. Ageing of a phosphate ceramic used to immobilize chloride-contaminated actinide waste.  United States: N. p., 2009. 
        Web.  doi:10.1016/j.jnucmat.2008.12.035.

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                    Metcalfe, Brian, Donald, Ian W., Fong, Shirley K., Gerrard, Lee A., Strachan, Denis M., & Scheele, Randall D. Ageing of a phosphate ceramic used to immobilize chloride-contaminated actinide waste.  United States.  https://doi.org/10.1016/j.jnucmat.2008.12.035

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                    Metcalfe, Brian, Donald, Ian W., Fong, Shirley K., Gerrard, Lee A., Strachan, Denis M., and Scheele, Randall D. 2009.  
        "Ageing of a phosphate ceramic used to immobilize chloride-contaminated actinide waste".  United States.  https://doi.org/10.1016/j.jnucmat.2008.12.035.

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@article{osti_964613,

  title        = {Ageing of a phosphate ceramic used to immobilize chloride-contaminated actinide waste},

  author       = {Metcalfe, Brian and Donald, Ian W. and Fong, Shirley K. and Gerrard, Lee A. and Strachan, Denis M. and Scheele, Randall D.},

  abstractNote = {At AWE, we have developed a process for the immobilization of ILW waste containing a significant quantity of chloride with Ca3(PO4)2 as the host material. Waste ions are incorporated into two phosphate-based phases, chlorapatite [Ca5(PO4)3Cl] and spodiosite [Ca2(PO4)Cl]. Non-active trials performed at AWE with Sm as the actinide surrogate demonstrated the durability of these phases in aqueous solution. Trials of the process, in which actinide-doped materials were used, wer performed at PNNL where the waste form was found to be resistant to aqueous leaching. Initial leach trials conducted on 239Pu /241Am loaded ceramic at 40°C/28 days gave normalized mass losses of 1.2 x 10-5 g.m-2 and 2.7 x 10-3 g.m-2 for Pu and Cl respectively. In order to assess the response of the phases to radiation-induced damage, accelerated ageing trials were performed on samples in which the 239Pu was replaced with 238Pu. No changes to the crystalline structure of the waste were detected in the XRD patterns after the samples had experienced an α radiation dose of 4 x 1018 g-1. Leach trials showed that there was an increase in the P and Ca release rates but no change in the Pu release rate.},

  doi          = {10.1016/j.jnucmat.2008.12.035},

  url          = {https://www.osti.gov/biblio/964613},
  journal      = {Journal of Nuclear Materials},

  issn         = {0022-3115},

  number       = 2,

  volume       = 385,

  place        = {United States},

  year         = {Tue Mar 31 00:00:00 EDT 2009},

  month        = {Tue Mar 31 00:00:00 EDT 2009}

}

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