The surrogate measure also covers intact gauges in the recycling stream, which though not causing exposures, are still a concern because they are beyond controls. At present, a quantitative evaluation of the impacts to health from melting a nuclear gauge at a steel mill is difficult to perform. A large amount of steel, although contaminated, will give more shielding than a small amount of steel. Cesium vaporizes from molten steel and slag and resides in the furnace dust. Contamination is not found in steel when cesium has been melted.
Cobalt forms an alloy with steel.
A ventilation hood in a melt shop collects dust from the furnace. At some mills, the furnace is ventilated while it is operating. When a furnace is opened, a plume of dust rises up to the hood, but not all of the plume enters the hood. Inhalation exposures are more than just a function of the collection efficiency. Predicted exposures are complicated by the rate at which radionuclides are purged from molten steel.