Advanced Operational Practices for Reducing of Carbon-14 Stack Emissions at CANDU Plant

Carbon-14 (C-14), a pure β-emitting radioisotope of carbon with half-life of 5730 years, may be found in the radio-waste from nuclear power plants. Among the nuclear power plants, CANDU plants, which use heavy water as moderator and coolant, emit a larger amount of C-14 than LWRs since heavy water contains a higher isotopic abundance of oxygen-17, one of major source materials for C-14 production at nuclear power plants. The monitoring for stack emission of C-14, which was initiated at four domestic CANDU units in 1998, revealed that during 1998 and 1999, relatively high C- 14 emission rates were observed at three units. In order to find measures to reduce those C-14 stack emissions, a special monitoring program had been conducted from July 2000 to August 2002 at Unit W-3