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Title: Development of Advanced In-Situ Techniques for Chemistry Monitoring and Corrosion Mitigation in SCWO Environments

Technical Report ·
DOI:https://doi.org/10.2172/781020· OSTI ID:781020

This project is developing sensing technologies and corrosion monitoring techniques for use in super critical water oxidation (SCWO) systems to reduce the volume of mixed low-level nuclear waste by oxidizing organic components in a closed cycle system where CO2 and other gaseous oxides are produced, leaving the radioactive elements concentrated in ash. The technique uses water at supercritical temperatures under highly oxidized conditions by maintaining a high fugacity of molecular oxygen in the system, which causes high corrosion rates of even the most corrosive resistant reactor materials. This project significantly addresses the high corrosion shortcoming through development of (a) advanced electrodes and sensors for in situ potentiometric monitoring of pH in high subcritical and supercritical aqueous solutions, (b) an approach for evaluating the association constants for 1-1 aqueous electrolytes using a flow-through electrochemical thermocell; (c) an electrochemical noise sensor for the in situ measurement of corrosion rate in subcritical and supercritical aqueous systems; (d) a model for estimating the effect of pressure on reaction rates, including corrosion reactions, in high subcritical and supercritical aqueous systems. The project achieved all objectives, except for installing some of the sensors into a fully operating SCWO system.

Research Organization:
Pennsylvania State Univ., University Park, PA (US)
Sponsoring Organization:
USDOE Office of Energy Research (ER) (US)
DOE Contract Number:
FG07-96ER62303
OSTI ID:
781020
Report Number(s):
DOE/ER/62303; Project Number 55171; Project Number 55171; TRN: US0102810
Resource Relation:
Other Information: PBD: 31 Mar 2000
Country of Publication:
United States
Language:
English