Getters for improved technetium containment in cementitious waste forms

JOURNAL OF HAZARDOUS MATERIALS

卷:341

Article

Asmussen, R. Matthew¹  Pearce, Carolyn I.¹  Miller, Brian W.²  Lawter, Amanda R.¹  Neeway, James J.¹  Lukens, Wayne W.³  Bowden, Mark E.¹  Miller, Micah A.¹  Buck, Edgar C.¹  Serne, R. Jeffery¹  Qafoku, Nikolla P.¹ 

[1] Pacific Northwest Natl Lab, 902 Battelle Blvd, Richland, WA 99354 USA

[2] Univ Arizona, Coll Opt Sci, 1630 E Univ Blvd, Tucson, AZ USA

[3] Lawrence Berkeley Natl Lab, 1 Cyclotron Rd, Berkeley, CA USA

关键词: Nuclear waste management;    Technetium;    Cementitious materials;    Waste forms;    Hanford site;    Getters;   

DOI  :  10.1016/j.jhazmat.2017.07.055

来源: Elsevier

【 摘 要 】

A cementitious waste form, Cast Stone, is a possible candidate technology for the immobilization of low activity nuclear waste (LAW) at the Hanford site. This work focuses on the addition of getter materials to Cast Stone that can sequester Tc from the LAW, and in turn, lower Tc release from the Cast Stone. Two getters which produce different products upon sequestering Tc from LAW were tested: Sn(II) apatite (Sn-A) that removes Tc as a Tc(IV)-oxide and potassium metal sulfide (KMS-2) that removes Tc as a Tc(IV)-sulfide species, allowing for a comparison of stability of the form of Tc upon entering the waste form. The Cast Stone with KMS-2 getter had the best performance with addition equivalent to similar to 0.08 wt% of the total waste form mass. The observed diffusion (D-obs) of Tc decreased from 4.6 +/- 0.2 x 10(-12) cm(2)/s for Cast Stone that did not contain a getter to 5.4 +/- 0.4 x 10(-13) cm(2)/s for KMS-2 containing Cast Stone. It was found that Tc-sulfide species are more stable against re-oxidation within getter containing Cast Stone compared with Tc-oxide and is the origin of the decrease in Tc D-obs when using the KMS-2. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

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