Contamination Sources & Detection | Advanced Power Plant Chemistry

≡ Course IndexModule 19 of 48 · Track 3 — Condensate & Feedwater Chemistry

Sources Cataloged

6

across the cycle

Primary Signal

Varies

by source type

Method

Checklist

systematic elimination

Source	What It Introduces	Primary Chemistry Signal	Covered In
Condenser tube leak	Raw cooling water — Na, Cl, minerals	Cation conductivity + sodium rise	Module 1.6, 3.1
Heater tube leak	Feedwater into extraction path (usually)	Inventory/level anomaly first	Module 3.4
Air in-leakage	Oxygen, nitrogen at vacuum points	Rising DA/feedwater dissolved O₂	Module 3.3
Makeup water upset	Hardness, TDS from pretreatment failure	Conductivity, hardness trend	Module 1.3
Copper alloy corrosion	Dissolved/particulate copper	Rising feedwater copper	Module 3.5
Chemical feed error	Wrong dose/blend of treatment chemical	Isolated parameter shift, no load correlation	Module 2.1–2.6

Click any source to see its diagnostic fingerprint. Working a real excursion means matching the observed signal pattern against this list rather than guessing at a single likely cause.

Select a contamination source to learn more.

Building the Full Picture

Modules 3.1 through 3.5 each covered a specific piece of the condensate/feedwater system and its associated risks in depth. This module steps back and surveys all of them together as a single troubleshooting checklist — the mental list a chemistry tech should be able to run through quickly when an unexplained parameter shift shows up anywhere in this part of the cycle.

Six Major Contamination Paths

Condenser tube leak (Module 3.1): Raw cooling water enters through a failed tube, carrying sodium, chloride, and other minerals. Signature: rising cation conductivity paired with rising sodium, the pattern established in Module 1.6.

Feedwater heater tube leak (Module 3.4): Usually feedwater moving into the extraction steam/drain path rather than true contamination entering the cycle, especially on HP heaters. Signature: inventory or drain tank level anomalies often precede any dramatic chemistry signal.

Air in-leakage (Module 3.3): Atmospheric air entering through any sub-atmospheric (vacuum) point — condenser, LP heaters, low-pressure piping joints. Signature: rising dissolved oxygen at the DA outlet or feedwater, sometimes without any corresponding conductivity change, distinguishing it from a liquid contamination path.

Makeup water treatment upset (Module 1.3): A softener, RO, or demin system underperforming lets hardness or TDS through into the cycle via makeup water. Signature: gradual conductivity or hardness trend, often correlating with known makeup water system issues rather than appearing suddenly.

Copper alloy corrosion (Module 3.5): Ongoing or accelerated corrosion of copper alloy components releasing dissolved/particulate copper. Signature: rising feedwater copper, potentially correlated with a separate oxygen excursion or mechanical erosion issue.

Chemical feed error (Tracks 1–2): Incorrect dosing, wrong chemical blend, or a calibration drift in any treatment feed system. Signature: an isolated parameter shift specific to the chemical involved, generally without the load correlation of hideout or the multi-parameter pattern of a leak.

Using the Checklist — Signal Pattern, Not Guesswork

The diagnostic discipline built across Modules 1.5, 1.6, and 2.7 applies directly here: read the pattern across multiple parameters rather than reacting to a single reading. A rising conductivity reading alone could fit several of these six sources — what narrows it down is which other parameters move alongside it, and how.

A practical narrowing sequence: Does dissolved oxygen move without conductivity change? Suspect air in-leakage first. Does sodium rise alongside cation conductivity? Suspect condenser leak first. Does the shift correlate with a maintenance activity, chemical batch change, or feed pump work? Suspect a feed error first. Is copper elevated with normal oxygen and no conductivity change? Suspect mechanical erosion-corrosion on copper alloy components first. None of these are certainties, but they're a faster starting point than checking all six sources with equal priority every time.

Why Some Sources Are Easy to Miss

Heater leaks and makeup water upsets both tend to develop gradually and can be mistaken for normal operational drift if trend review isn't disciplined — recall the trend-reading emphasis from Module 1.4 and the ratio-drift scenario in Module 2.7.
Air in-leakage is easy to overlook because it produces no conductivity signal at all — a tech watching only conductivity and pH could miss a real, worsening air in-leakage problem entirely.
Copper corrosion trends are sometimes not monitored at all on units where copper alloys were installed decades ago and the monitoring program was never updated to include it — a genuine programmatic gap worth checking for on any older unit.

Field note: A chemistry tech who can run this six-source mental list quickly, and knows which one or two parameters best distinguish between them, will diagnose real problems faster than one who only knows the textbook definitions of each source in isolation. This module is deliberately built as a checklist for exactly that reason.

Contamination Path

A specific mechanism by which an unwanted substance can enter the condensate/feedwater system, each with a characteristic chemistry signature.

Signal Pattern

The combination of which chemistry parameters move, and how, used to distinguish between multiple possible contamination sources presenting similar individual readings.

Narrowing Sequence

A practical diagnostic order for checking likely causes based on which parameters are and aren't affected, used to prioritize investigation rather than checking all sources with equal effort.

Programmatic Gap

A monitoring or procedural omission (such as not tracking copper on an older unit) that persists because it was never updated to reflect current equipment or risks.

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