Scientists Criticize NIF
WASHINGTON, June 4, 2007 -- The National Ignition Facility is one of three major components of the Stockpile Stewardship Program at the Department of Energy that are all seriously over budget and behind schedule, according to a report issued last week by the Federation of American Scientists (FAS).
FAS was formed in 1945 by atomic scientists from the Manhattan Project to promote humanitarian uses of science and technology. Its paper, "The Stockpile Stewardship Program: Fifteen Years On," reviews the status of the experimental devices that support the Stockpile Stewardship Program (SSP), describes how each experiment is supposed to work, and identifies the problems that have been encountered. SSP was developed because of concerns that over time a nuclear weapon's reliability could decline.
The report specifically addresses three projects: The National Ignition Facility (NIF) uses laser beams to compress a hydrogen target to densities and pressures where fusion would occur; the Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility uses x-rays to view an imploding fission primary in real time; and the Accelerated Strategic Computing Initiative (ASCI) -- renamed Advanced Simulation and Computing (ASC) -- develops supercomputers and associated software to model nuclear warheads and predict their behavior using information gathered from other experiments.
The National Ignition Facility (NIF), the world's largest laser facility and the most expensive project of the three, was proposed to be built at Lawrence Livermore National Laboratory (LLNL) in Livermore, Calif., to increase understanding of the thermonuclear, or fusion, portion of nuclear weapons by simulating some of the conditions within a detonating nuclear warhead.
Featuring a three-story-deep subterranean chamber housed in a football-stadium-sized building, NIF is centered around a 130-ton spherical target chamber designed to contain a small thermonuclear explosion. The target chamber spans 30 feet across with 4-in. thick aluminum alloy walls and will accommodate 192 laser beams, which will be focused on a single tiny 3-mm tritium and deuterium fuel pellet in the center of the sphere. As the x-rays heat the pellet’s fuel to millions of degrees, some of the nuclei will fuse and generate over 1.8 million joules, lasting one billionth of a second.
When DoE first announced the NIF program in 1996, its construction cost was estimated at $1.07 billion and completion was expected in 2002. Now, according to the FAS report, after years of mismanagement and technological problems, its first experiments are expected to take place in 2010 and the construction cost estimates have more than doubled.
The use of a "great deal" of untested new technologies in the device has generated much criticism from other DoE scientists and from anti-nuclear groups, FAS said, and caused the filing of several lawsuits against the DoE by environmentalists.
"The physics community is not championing NIF, they do not believe it will push back the frontiers of science, certainly not enough to justify the cost. NIF may, however, serve a significant national security function if completed successfully," FAS said in the report.
One of the NIF's major problems, according to the report, dates back to 1999, when engineers found they couldn't keep the laser optics free of dust. While pursuing solutions that ultimately added $350 million to the project's cost, lab officials hid the problem from senior Energy Department officials and Congress and lied about it, leading to the firing of several LLNL employees.
Since a 2000 audit by the General Accounting Office, some of NIF's biggest problems -- such as the dust issue -- have been addressed, FAS said. By 2003, the dust issue was solved by building an enormous cleanroom and installing the optics in modular dust-free units, while new methods were developed to produce thousands of highly polished pieces of laser glass that are part of the beam amplifiers assembly.
Challenges remaining, however, include getting the 192 laser beams to focus perfectly on the fuel pellet. As of November 2005, eight of the beams were operational and initial testing of four of the eight was successful, according to NIF.
There are also questions remaining about the pellet itself. The pellet's shell was to be made of plastic, but was replaced with beryllium, which can withstand intense heat, is a good conductor, and molecularly stable. However, it is still uncertain as to whether beryllium can be machined to specification. Last year Congress directed another outside review to report how the development of a beryllium target might affect NIF's completion timetable, FAS said.
"NIF’s technical problems remain difficult hurdles to clear, and may be solvable, but other cumbersome issues can be traced back to poor management, especially in the early part of the program’s life.
"Even though the cost of completing NIF at this point is probably greater than the original total estimated cost, it seems politically inevitable that NIF will be carried through to laser operation and we will not know NIF’s value to taxpayers until its commissioning tests in 2009-2010. If it then fails, there is strong reason for canceling the project at that point," FAS said.
"All of the expensive SSP experiments were initiated because of the cessation of nuclear testing, with the expectation that they would be essential to maintaining the nuclear stockpile," said Ivan Oelrich, vice president of strategic security at FAS, in a statement. "We understand nuclear weapons much better now than we did when we were testing. It is time to reevaluate which of these expensive experiments we still need. The DoE is even proposing to move away from stockpile stewardship to a reliable, replacement warhead, which could avoid the need for the SSP experiments altogether.
"Based on unclassified sources, it appears that the connection between NIF and the current SSP is at best indirect," said Oelrich. "We believe that NIF could be ended without reducing the confidence in the existing nuclear stockpile."
NIF in particular has been promoted by its supporters as a way to attract top scientists to DoE and the SSP, FAS said, but universities and industry are now conducting more cutting-edge research. The billions of dollars devoted to NIF might be better spent if they directly supported university research of interest to DoE, or to create smaller but scientifically more interesting experiments within the labs, FAS said.
The full report can be viewed at: www.fas.org
- The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
MORE FROM PHOTONICS MEDIA