The Plowshare program was both a public relations ploy and a serious scientific study. It was an attempt to see if nuclear bombs could be used in peaceful constructive ways. If it had been successful, America would pretty much be humming by now.
During the late 1930s and early 1940s, the entire focus of the atomic program was to create the weapon to end any war, even one as all-consuming as World War II. After the war, the makers of the bomb saw its power, and their own uneasy public, and tried to think of ways to both soothe the American people, and put the bombs to good use. Some of their minds drifted to the Bible verse in Isiah 2:4, "They shall beat their swords into plowshares, and their spears into pruning-hooks: nation shall not lift up sword against nation, neither shall they learn war any more."
It sounds good — until the interpretation works out as "Let's bomb Alaska, until it has a whole new harbor." Operation Plowshare was simultaneously touching and terrifying. It was touching, because it honestly believed that extraordinarily ambitious projects that might do the nation a great deal of good could be achieved through this supposedly destructive force. Terrifying, because proposed projects including widening the Panama Canal with a bomb in one fell swoop, and just bombing an entire route through Nicaragua.
Also terrifying, because there were a number of tests actually conducted to see if the idea might work. Project Gnome attempted to created energy by bombing underground aquifers. Project Sedan was to just keep bombing parts of America, until we figured out how big a crater each bomb would make. Project Rulison and Project Gasbuggy were an attempt to free natural gas with nuclear explosions. In total, over twenty-five different tests were conducted all over the nation.