Copper, nickel, zinc, and common cations in the water-steam circuit of a boiling water reactor (BWR)

Significance of the Topic

Maintaining ultrapure water chemistry in the boiling water reactor water-steam circuit is essential for plant reliability, corrosion control, and minimization of radiological hazards. Trace levels of metal ions and common cations can originate from corrosion products or external contamination, influencing material integrity and operational safety.

Objectives and Study Overview

This application note demonstrates a robust ion chromatography method capable of quantifying sub-ppb concentrations of copper, nickel, zinc, and standard cations (sodium, ammonium, magnesium, calcium, potassium) in a simulated BWR water-steam circuit matrix. The goals were to achieve high sensitivity, reproducibility, and accuracy for routine monitoring in nuclear power plant feedwater and condensate systems.

Methodology

An inline preconcentration approach (MiPCT) was employed to concentrate analytes from large sample volumes. Separation used a combination of Metrosep cation columns with a nitric/oxalic acid eluent. Detection was performed via direct conductivity measurement. Key method parameters included:

• Flow rate: 0.4 mL/min
• Injection volume after preconcentration: 9.8 mL
• Pressure up to 25 MPa
• Analysis time: 22 minutes per run
• Column temperature: 32 °C

Used Instrumentation

• 850 Professional IC Cation
• IC Conductivity Detector
• 858 Professional Sample Processor
• 2×800 Dosino for liquid handling
• 849 Level Control for inline eluent preparation

Main Results and Discussion

Measured concentrations of all cations and transition metals in the artificial BWR matrix were consistently 0.5 ug/L. Method performance metrics at 1.0 ug/L spiking level showed:

• Recoveries between 93.1% and 119.0% (ammonium at higher blank contribution)
• Relative standard deviations (RSD) below 6% for all analytes
• Correlation coefficients exceeding 0.9996, confirming excellent linearity

These results confirm the method’s capability for reliable trace-level quantification in challenging matrices.

Benefits and Practical Applications

The described IC approach offers:

• Enhanced sensitivity through online preconcentration
• High throughput suitable for routine plant monitoring
• Minimal sample preparation and low reagent consumption
• Trace metal and cation profiling to guide corrosion control measures

Future Trends and Opportunities

Emerging developments may include integration of real-time inline sensors for continuous monitoring, advancement of miniaturized column technologies for faster separations, and application of chemometric tools for automated quality control. Coupling with digital plant data systems will support predictive maintenance and more responsive water chemistry management.

Conclusion

This application note outlines a sensitive, reliable IC method for simultaneous determination of key metal impurities and cations in BWR water-steam circuits. The procedure supports nuclear plant water chemistry control with strong analytical performance and practical workflow integration.