The Importance of Online Sodium Monitoring in the Water-Steam Cycle

Sodium is one of the most sensitive indicators of contamination entering the water-steam cycle, which is why EPRI designates it a core parameter in its Cycle Chemistry Guidelines: continuously monitored online, with alarm limits displayed in the control room. Regardless of its chemical form, sodium in condensate, feedwater or steam raises the risk of stress corrosion cracking, including in turbine materials. Sodium measurement is also the basis for determining total carryover of boiler drum water into steam. At the low concentrations that matter, reliable measurement is only possible with online analyzers, not grab samples. 

This session covers the recommended sampling points and target values for sodium across the cycle, then turns to the analyzers themselves: the design features and capabilities that separate a dependable measurement from one that drifts or fails. Plant chemists evaluating new instrumentation will leave knowing which analyzer features are essential and which are not, and how to specify equipment that delivers reliable readings with minimal malfunction risk. 

For chemistry staff at drum boiler and combined cycle plants, this is a working session on one of the few parameters where a single reliable number can catch condenser leaks, polisher breakthrough and carryover problems before they become tube or turbine damage.