Arlington Hts. joins nuclear age, but only to ensure better roads.(News)

Brace yourself: Arlington Heights has its own nuclear device.Lest residents of neighboring towns worry and press their own officials to get one, too, thus touching off a Northwest suburban arms race, Arlington Heights' device helps ensure the roads are properly built. And the state of Illinois says it's perfectly safe. The device in question is a "nuclear density moisture meter," used to determine the proper density and moisture of asphalt or paving stones.

Inspectors from the state's Department of Nuclear Safety visited the village hall Tuesday to check that the monitor is being properly stored and used and that all paperwork is in order. The monitor uses the element radium and works like radar, said Mark Schoeffmann, the village's engineering director.

The radium is stored in a lead-lined compartment, and once uncovered, its radiation penetrates the paving material, Schoeffmann said. "The more dense the material, the more is bounced back and received," he said. That gets measured against pre-set parameters and tells inspectors if the asphalt or stone is of the proper density.
"It's a very commonly used device," Schoeffmann said. While the results of Tuesday's inspection are not yet available, Arlington Heights has "a really good inspection history," said Joe Klinger, division chief for radioactive material at the state department. "On the last inspection (March 1996), they had no violations."The state department checks thousands of such monitors, ranging from smaller, older models like Arlington Heights', to newer, bigger models that use americium and cesium, Klinger said.

Those, Klinger added, are most commonly seen hanging off the rear of Illinois Department of Transportation trucks - those big, yellow, knee-high objects.Each monitor must be inspected at least once every five years, Klinger said. Users must prove they can properly handle the monitors before getting licenses and nuclear material for them, he said.