Selective removal of carbon-14 from ion exchange resins using supercritical carbon dioxide

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:476561

Dias, S A; Krasznai, J P ^[1]

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1. Ontario Hydro Technologies (OHT), Toronto, Ontario (Canada)

Ion exchange resins (IX) are used extensively in CANDU-PHWR (Canada Deuterium Uranium - Pressurized Heavy Water Reactor) and other reactor systems worldwide to remove ionic contaminants from various coolant circuits. Spent IX resins represent a significant volume of low and intermediate level radioactive waste. The presence of long-lived C-14 which is found in significant quantities in IX resins from CANDU reactors, complicates the disposal of these resins. Several experiments were conducted with carbon dioxide under subcritical and supercritical conditions to determine the feasibility of removing C-14 present as carbonate and/or bicarbonate on IX resins. It has been established that resins containing inorganic C-14 undergo rapid isotopic exchange when exposed to inactive carbon dioxide under supercritical conditions. This treatment reduces the C-14 to the limits of detection and leaves other radioisotopes on the resins largely unaffected. This selective and highly efficient means to remove long-lived C-14 activity from CANDU spent IX resins allows the resin waste to be reclassified as low level waste. This lower classification simplifies the handling, transportation and eventual disposal of IX resins which translates to a very significant cost saving. Since the process is selective the C-14 can be enriched and recovered for commercial purposes.

• OSTI ID: 476561
• Report Number(s): CONF-960804--Vol.3
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
40 CHEMISTRY
CARBON 14
CARBON DIOXIDE
ION EXCHANGE MATERIALS
ISOTOPIC EXCHANGE
RADIOACTIVE WASTE PROCESSING
SEPARATION PROCESSES
SUPERCRITICAL STATE