Nuclear industry water analysis: Sizewell B Nuclear Power Plant Chemistry Laboratory, EDF UK

Significance of the Topic

Ion chromatography is critical for monitoring trace anionic impurities in nuclear power plant coolant and condensate systems to prevent stress corrosion and maintain plant integrity over decades. Precise detection at the sub-µg/L level ensures corrosion inhibitors do not interfere with analysis and supports reliable power generation.

Objectives and Study Overview

This study at the Sizewell B Nuclear Power Plant Chemistry Laboratory aimed to enhance the sensitivity of anion analysis in ammoniated condensate and lithium-borated water. It compared the performance of Thermo Scientific Dionex CR-CTC Continuously Regenerated Cation Trap Column II and III for inline removal of interferences to achieve detection limits down to 10 ppb.

Methodology and Instrumentation Used

The analysis employed a Thermo Scientific Dionex Integrion HPIC system configured with:

• An AXP Auxiliary Pump for sample loading
• A Dionex CR-CTC II or III for inline cation removal
• High-pressure inline filters (0.5 µm) to trap particulates
• IonPac AG15 guard column, AS15 analytical column (2 × 250 mm), and AC10 concentrator column
• An ADRS 600 suppressor and EGC 500 KOH eluent generator with CR-ATC 600 anion trap

Inline pretreatment eliminated up to 10 mg/L ammonia or 4 mg/L lithium, restoring peak shape and response without offline regeneration.

Main Results and Discussion

Inline use of the CR-CTC III improved regeneration capacity, maintaining consistent fluoride response over more than 50 daily check injections. Compared to the CR-CTC II, the CR-CTC III delivered lower RSD (< 3.1% vs. up to 7.1%) for a 10 ppb anion standard in 10 ppm ammonia. The system operated reagent-free, reducing maintenance and extending calibration intervals during high-throughput periods.

Benefits and Practical Applications of the Method

• Reliable sub-ppb quantification of fluoride, chloride, sulfate, and phosphate
• Automated, reagent-free inline removal of matrix interferences
• Minimized method downtime and extended calibration stability
• Enhanced productivity during routine and outage sampling campaigns
• Safer alternative to flame photometry by eliminating explosive gases

Future Trends and Potential Applications

Ongoing developments may push detection limits lower via automated autosampler dilution and sample prep. The inline trap approach can be adapted to broader power plant water streams, including high-purity feedwater and closed-cooling circuits, and extended to trace metal monitoring.

Conclusion

The Dionex CR-CTC III, integrated with a reagent-free IC workflow, enables robust, low-level anion analysis in challenging nuclear power plant matrices. Its automated regeneration and inline cleanup improve precision, extend operation cycles, and support critical water chemistry control.

Reference

• Thermo Fisher Scientific. Application Update AU-000610. Trace organic acids and inorganic anions in boric acid-treated power plant waters.
• Thermo Fisher Scientific. Application Note AN-277. Fast determination of transition metals in power industry waters.
• Thermo Fisher Scientific. Application Note AN-73852. Trace anions in high-purity waters via direct injection.
• Thermo Fisher Scientific. Application Note AN-1058. Polyacrylic Acid in PWR secondary feedwater.