A remote, contactless microprocessor-based control system has been designed, developed, tested, and used at Pacific Northwest Laboratory that accurately positions glass-receiving canisters beneath a radioactive liquid-fed ceramic melter and monitors the height and extent of cross-sectional glass fill. Both tasks are accomplished using in-cell gamma-ray sources and out-of-cell detection, analysis and data interpretation equipment. The system aligns the canister axis with the melter overflow section to within ≈3 mm. The canister glass level at 11 fixed elevations is measured to within ±5 mm, while as little as 5 mm of linear cross-sectional voiding (or equivalent glass thickness) can be detected in 30-cm-diam canisters.