Determination of carbon-14 levels in heavy water and groundwaters

Analysis and processing of samples for a carbon-14 monitoring program at a radioactive waste storage site

“…In both cases, the total carbon recovery (gravimetric) was consistent at 85.9 ± 2.7% and 86.9 ± 2.6% for the blank and spiked pellets, respectively. The extraction yield of the 14 C in the spiked pellets was 96.0 ± 4.2%, which is close to the value of 94.2 ± 6% reported in our previous work 5 for aqueous solutions. The gravimetric yields ( ~86%) are different from 100% probably because of the water of hydration of the solids involved in the pellet preparation (higher weight per pellet, thus a lower weight of C per pellet).…”

“…The counting procedure consisted of mixing 2 mL of the 2 M NaOH solution of interest (samples, standards, procedural blanks, instrument blanks) with 18 mL of Hionic Fluor scintillation cocktail (Packard Instruments, Meriden, CT). 5 In all cases, glass scintillation vials with cone-shaped plastic liner caps were used. The EG&G Wallac 1414 instrument was used, with a full window (0-1024 channels).…”

“…Under these circumstances, it was difficult to check for the quantitative transfer of total CO 2 , which was done gravimetrically. In addition, memory effects were experienced with high 14 C activity samples, and incomplete tritiated water removal was observed, making liquid scintillation analysis difficult for 14 C. To overcome these difficulties, we have modified the hardware and method displayed in a companion paper, 5 which featured the quantitative removal of tritiated water, and no or little memory effect between samples. Recoveries and consistencies of this modified stripping method are reported here.…”

Determination and human health risk assessment of TFWT, OBT and carbon-14 in seafood around Qinshan Nuclear Power Plant

“…14 C is primarily released as gases and liquids through wastewater pipelines and chimneys. While the 14 C concentrations in reactor water sampled during the operation were reported ranging within 0.1 – 2 MBq/L, those taken during shutdown and in groundwater near a waste management area ranged from −100 to 1800 Bq/L ( Caron et al, 2000 ). 14 C, which exists as carbon dioxide (CO 2 ), mixes with non-radioactive CO 2 in the air, participates in the photosynthesis of plants, enters into the food chain, and endangers the environment and human body.…”