Cesium retention and release from sulfur polymer concrete matrix under normal and accidental conditions

Piotr Szajerski; Agnieszka Bogobowicz; Andrzej Gasiorowski

doi:10.1016/j.jhazmat.2019.121180

Cesium retention and release from sulfur polymer concrete matrix under normal and accidental conditions

J Hazard Mater. 2020 Jan 5:381:121180. doi: 10.1016/j.jhazmat.2019.121180. Epub 2019 Sep 6.

Authors

Piotr Szajerski¹, Agnieszka Bogobowicz², Andrzej Gasiorowski³

Affiliations

¹ Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590, Lodz, Poland. Electronic address: szajer@mitr.p.lodz.pl.
² Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590, Lodz, Poland. Electronic address: 188993@edu.p.lodz.pl.
³ Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590, Lodz, Poland. Electronic address: agasiorowski@mitr.p.lodz.pl.

PMID: 31561122
DOI: 10.1016/j.jhazmat.2019.121180

Abstract

This paper proposes an efficient two-stage process for stabilization and solidification of the Cs-137 isotope in a sulfur polymer concrete (SPC) matrix. Lignite slag (SL) and fly ash (FA) were applied as active fillers for cesium immobilization. To study the release of Cs-137 isotope and determine the tracer activity in the leachates, we applied a slightly modified ANSI/ANS 16.1 protocol and the gamma spectrometry technique. The measured effective diffusion coefficients for the Cs-137 isotope were between 0.84·10^-9 and 3.10·10^-9 cm²·s^-1. Normalized leaching rates were within the range of 1.74·10^-5 - 3.85·10^-5 g·cm^-2·d^-1, fulfilling acceptance criteria for radioactive wasteforms. As well as standard leaching under static conditions, we also studied dynamic leaching of SPC samples at increased temperatures and leaching in an aggressive environment. The Cs-137 effective diffusion coefficients were found to increase by 3 - 4 orders of magnitude (10^-6 - 10^-5 cm²·s^-1), while the normalized leaching rate reached values of up to 2.36·10^-3 g·cm^-2·d^-1 after 28 days of leaching. The proposed cesium immobilization mechanism is based on the formation of cesium silicate and aluminosilicate phases, together with effective matrix sealing during the SPC manufacturing process.

Keywords: Cesium immobilization; Diffusion; Industrial waste; Leaching; Sulfur polymer concrete.

Publication types

Research Support, Non-U.S. Gov't