Cesium and Strontium Contamination of Nuclear Plant Stainless Steel: Implications for Decommissioning and Waste Minimization

Research output: Contribution to journalArticle

  • External authors:
  • Adam Lang
  • Clemens Walther
  • Martin Weiß
  • Hauke Bosco
  • Alex Jenkins

Abstract

Stainless steels can become contaminated with radionuclides at nuclear sites. Their disposal as radioactive waste would be costly. If the nature of steel contamination could be understood, effective decontamination strategies could be designed and implemented during nuclear site decommissioning in an effort to release the steels from regulatory control. Here, batch uptake experiments have been used to understand Sr and Cs (fission product radionuclides) uptake onto AISI Type 304L stainless steel under conditions representative of spent nuclear fuel storage (alkaline ponds) and PUREX nuclear fuel reprocessing (HNO3). Solution (ICP-MS) and surface measurements (GD-OES depth profiling, TOF-SIMS, and XPS), and kinetic modelling of Sr and Cs removal from solution, were used to characterize their uptake onto the steel, and define the chemical composition and structure of the passive layer formed on the steel surfaces. Under passivating conditions (when the steel was exposed to solutions representative of alkaline ponds and 3 and 6 M HNO3), Sr and Cs were maintained at the steel surface by sorption / selective incorporation into the Cr-rich passive film. In 12 M HNO3, corrosion and severe intergranular attack led to Sr diffusion into the passive layer and steel bulk. In HNO3, Sr and Cs accumulation were also commensurate with corrosion product (Fe, Cr) re-adsorption and in the 12 M HNO3 system, XPS documented the presence of Sr and Cs chromates.

Bibliographical metadata

Original languageEnglish
JournalACS Omega
Publication statusAccepted/In press - 31 Jul 2019

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