Scientists have long sought easier ways to make the costly material known as enriched uranium — the fuel of nuclear reactors and bombs, now produced only in giant industrial plants.

One idea, a half-century old, has been to do it with nothing more substantial than lasers and their rays of concentrated light. This futuristic approach has always proved too expensive and difficult for anything but laboratory experimentation.

Until now.

In a little-known effort, General Electric has successfully tested laser enrichment for two years and is seeking federal permission to build a $1 billion plant that would make reactor fuel by the ton.

That might be good news for the nuclear industry. But critics fear that if the work succeeds and the secret gets out, rogue states and terrorists could make bomb fuel in much smaller plants that are difficult to detect.