In this regard, others have assessed the NIF with the conclusion that the concerns about nonproliferation were manageable, that the risks could be made acceptable, and that the NIF could contribute positively to U.S. arms control and nonproliferation goals. One goal of the ICF program is to explore all of these elements in a laboratory setting. The DOE has stated that the primary scientific goal of the ICF program is the release of significant fusion energy in the laboratory. ICF requires that a small mass of deuterium-tritium fuel be rapidly compressed and heated to ignition, so that the initial fusion energy produced will induce further fusion in the fuel before the mass disassembles. In ICF, a spherical fuel capsule of a few millimeters in size is compressed by ablation of material from the capsule surface.
Compression is achieved by either direct or indirect drive.
In direct drive, laser or ion beams impinge directly on the capsule surface, causing ablation and compression. Relative to direct drive, indirect drive suffers the inefficiency of x-ray conversion, but it imposes less stringent requirements on beam balance and uniformity. The DOE's ICF program began formally in 1963 and was established as a separate budget line item in 1976. Several of the National Laboratories, universities, and commercial firms have participated in this program. Several major facilities are currently active in performing experiments relevant to both direct and indirect drive.