Chromium in aqueous nitrate plutonium process streams: Corrosion of 316 stainless steel and chromium speciation

Journal Article · Sun Dec 31 00:00:00 EST 1995 · Waste Management

DOI:https://doi.org/10.1016/0956-053X(96)00002-5· OSTI ID:367874

Smith, W H; Purdy, G M ^[1]

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1. Los Alamos National Lab., NM (United States). Nuclear Materials Technology Div.

This study was undertaken to determine if chromium(+6) could exist in plutonium process solutions under normal operating conditions. Four individual reactions were studied: the rate of dissolution of stainless steel, which is the principal source of chromium in process solutions; the rate of oxidation of chromium(+3) to chromium(+6) by nitric acid; and the reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel and with oxalic acid. The stainless steel corrosion rate was found to increase with increasing nitric acid concentration, increasing hydrofluoric acid concentration, and increasing temperature. Oxidation of chromium(+3) to chromium(+6) was negligible at room temperature and only became significant in hot concentrated nitric acid. The rate of reduction of chromium(+6) back to chromium(+3) by reaction with stainless steel or oxalic acid was found to be much greater than the rate of the reverse oxidation reaction. Based on these findings and taking into account normal operating conditions, it was determined that although there would be considerable chromium in plutonium process streams it would rarely be found in the (+6) oxidation state and would not exist in the (+6) state in the final process waste solutions.

• OSTI ID: 367874
• Journal Information: Waste Management, Vol. 15, Issue 7; Other Information: PBD: 1995
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
05 NUCLEAR FUELS
STAINLESS STEEL-316
CORROSION
FUEL REPROCESSING PLANTS
PROCESS SOLUTIONS
RADIOACTIVE WASTE MANAGEMENT
CHEMICAL ANALYSIS
CHROMIUM COMPOUNDS
DISSOLUTION
OXIDATION
REDUCTION
TOXIC MATERIALS
MIXTURES
LOW-LEVEL RADIOACTIVE WASTES
HAZARDOUS MATERIALS
CLASSIFICATION
RADIOACTIVE WASTE DISPOSAL
COST
WASTE FORMS
LEACHING
CONCRETES
LIQUID WASTES
CEMENTING