TY - JOUR
T1 - Cesium and Strontium Contamination of Nuclear Plant Stainless Steel
T2 - Implications for Decommissioning and Waste Minimization
AU - Lang, Adam R.
AU - Engelberg, Dirk L.
AU - Walther, Clemens
AU - Weiss, Martin
AU - Bosco, Hauke
AU - Jenkins, Alex
AU - Livens, Francis R.
AU - Law, Gareth T.W.
N1 - Funding information: We gratefully acknowledge funding from the Sellafield Ltd. Centre of Expertise in Decontamination and Effluent Treatment and thank Ben Spencer (University of Manchester) for assistance with XPS measurements. G.T.W.L. and F.R.L. acknowledge funding from NE/M014088/1 and ST/N002474/1.
PY - 2019/9/10
Y1 - 2019/9/10
N2 - 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 304 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 modeling 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 was also commensurate with corrosion product (Fe and Cr) readsorption, and in the 12 M HNO3 system, XPS documented the presence of Sr and Cs chromates.
AB - 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 304 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 modeling 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 was also commensurate with corrosion product (Fe and Cr) readsorption, and in the 12 M HNO3 system, XPS documented the presence of Sr and Cs chromates.
UR - https://www.scopus.com/pages/publications/85072312358
U2 - 10.1021/acsomega.9b01311
DO - 10.1021/acsomega.9b01311
M3 - Article
AN - SCOPUS:85072312358
SN - 2470-1343
VL - 4
SP - 14420
EP - 14429
JO - ACS Omega
JF - ACS Omega
IS - 11
ER -