lightly mineralized water

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For nuclear plant condensates and in particular ultrapure water the required guarantees cover all aspects: mineral, organic, particulate, bacteriological. The equipment must be increasingly performant.

In practice, solely continuous analysis give accurate results. Any sample shipping is damaging. The following list displays the main parameters that need to be taken into consideration:

resistivity

This measurement must be carried out in a circulation cell capable of detecting 25 Mohms · cm.

salts and metals

The required target concentration thresholds may be below 1 μg· L-1, for sodium and heavy metals among others. Some specific electrodes and ionic chromatography with an eluant suppression column and preconcentration may be required to reach those sensitivities.

TOC

Apparatus used to measure a drop in resistivity after the organic matter has been mineralised are the most appropriate (published detection threshold of 20 μg· L-1).

particle count

If the sample collection time is very short, measurements carried out on the spot without any dilution are correct and reproducible.

fouling indices

These indices are very low. Results are only significant if measurements are continuously carried out by a programmable logic controller

bacteriology

Grab samples typically produce representative results. The membrane filtration technique is appropriate because it allows for the filtration of volumes that are considerably greater than those set for potability inspections.

The required target concentration thresholds may be below 1 mg· L-1, for sodium and heavy metals among others. Some specific electrodes and ionic chromatography with an eluant suppression column and preconcentration may be required to reach those sensitivities.