What you saw was Hanford Nuclear reservation America's nuclear program began here.
But you probably saw the Yakima Firing range used by the Army as a Artillery practice area.
Interstate 82 (I-82) is a 143.58-mile (231.07 km) Interstate Highway that extends from I-90 in Ellensburg, Washington, to I-84 near Umatilla, Oregon, in the United States. In the state of Washington, it serves the cities of Ellensburg, Yakima, and the Tri Cities (via I-182), and in Oregon, it serves Umatilla and Hermiston. It is the major route westwards to Seattle and eastwards to Boise and Salt Lake City (via I-84 and I-15). I-82's designation is a violation of the Interstate system's numbering rules, as it is located north of I-84, and is also primarily a north-south route. I-84 was originally designated I-80N, but received its current number in 1980 as part of efforts to eliminate suffixed routes.