Real Time Nano-gravimetric Monitoring of Corrosion for Nuclear Decommissioning in Simulated Radioactive Environments - 16170

Conference · Fri Jul 01 04:00:00 EDT 2016

OSTI ID:22838050

Tzagkaroulakis, Ioannis; Boxall, Colin ^[1]; Trivedi, Divyesh ^[2]

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1. Engineering Department, Lancaster University, Lancaster, LA1 4YR (United Kingdom)
2. The National Nuclear Laboratory, Birchwood Park, Warrington WA3 6AE (United Kingdom)

Monitoring and understanding of corrosion on nuclear sites plays a key role in safe asset management and supporting informed choice of decontamination methods for steels due for decommissioning. Recent advances in Quartz Crystal Nano-balance (QCN) technology offer a means to monitor corrosion in-situ in radiologically harsh environments, in real time and with high sensitivity. Oxalic acid has been widely used in nuclear plants and installations as a corrosion inhibitor for carbon steels and as a decontamination cleaning agent due to its ability to remove rust from the surface of ferritic metals and alloys. As an exemplar system for decontamination, the corrosion behavior of mild carbon steel and pure iron samples in 1 wt% to 8 wt% oxalic acid solutions have, for the first time, been measured and compared in real time and in situ using the QCN. Corrosion rates measured using the QCN are found to agree with those obtained using corrosion current (i{sub CORR}) measurements, with the added advantages of: (i) real time and potentially in situ and higher sensitivity measurement; (ii) reduced uncertainty in the conversion of the QCN measured frequency change to a mass change-based corrosion rate compared to the conversion of the iCORR measured by LSV with Tafel extrapolation to similar; (iii) the provision of mechanistic insights into the action of oxalic acid on Fe-rich steels. We have also used the QCN to study the impact of radiolytically generated peroxide on the corrosion protection afforded by oxalate to Fe surfaces during oxalic acid-driven tank clear out. In so doing we have identified H{sub 2}O{sub 2} and oxalate concentrations under which that protection breaks down and elucidated the Fenton reaction assisted mechanism by which that breakdown occurs. (authors)

• Research Organization: WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
• OSTI ID: 22838050
• Report Number(s): INIS-US--19-WM-16170
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CARBON STEELS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
CORROSION
CORROSION INHIBITORS
CORROSION PROTECTION
DECOMMISSIONING
DECONTAMINATION
FERRITIC STEELS
HYDROGEN PEROXIDE
IRON
NUCLEAR POWER PLANTS
OXALATES
OXALIC ACID
RADIATION MONITORING
SENSITIVITY
TANKS