During chalk testing of the gasket hatch, if the line is not continuous, what is wrong?

• A. Beta contamination
• B. Alpha contamination
• C. Gamma contamination
• D. No contamination indicated

Answer: (A)

Chalk testing visualizes how surface contamination deposits on a seam by brushing chalk along the gasket area and looking at the pattern. If the chalk line around the hatch is continuous, it suggests a uniform transfer along the entire contact area, which aligns with the behavior of more penetrating contamination. When the line is not continuous, the chalk deposition isn’t uniform, which is characteristic of beta contamination, since beta particles have a moderate range and tend to deposit in patches rather than along the whole seam. Alpha contamination would typically show as isolated spots where chalk adheres strongly due to the very short range of alpha particles, and gamma contamination would usually produce a more even, continuous pattern due to its high penetration. So a broken, non-continuous chalk line indicates beta contamination on the gasket hatch.