Inspection, Testing, Documentation, and Quality Assurance
Inspection proves the system, not just the film
Inspection in nuclear coating work follows an approved inspection and test plan with hold points. Verify surface preparation, environmental conditions, mixing, wet-film and dry-film thickness, cure, adhesion, holidays, and final appearance. Dry-film thickness is statistically evaluated, commonly per SSPC-PA 2; average thickness alone does not prove compliance because low spots can leave the barrier too thin. Holiday testing detects pinholes and discontinuities; use the correct voltage and method so the test does not damage the coating. Adhesion tests may be destructive and must be planned. Documentation includes batch numbers, calibration records, environmental logs, nonconformance reports, and sign-offs. Personnel qualification matters: inspectors and applicators may need specific nuclear qualifications. Traps include accepting an average DFT while ignoring a low reading, holiday testing at excessive voltage, and treating documentation as after-the-fact clerical work.
Rule of thumb: if a measurement is out of specification, investigate with additional readings and repair, not with a more favorable average.
Worked example: A specification requires 8–12 mils DFT. Readings average 9 mils, but one area reads 6 mils. Add readings in that area and repair low thickness; the average does not override the minimum.