Comment
The National Ignition Facility
responds to the nuclear challenge
Victor H. Reis
The invention of the atom bomb changed, forever, the way in which humans relate to the basic matter of the universe. Today the Comprehensive Test Ban Treaty and the Nuclear Nonproliferation Treaty are important restraints on the spread and development of nuclear weapons.
Nuclear weapons will be a unique part of US national security far into the future, however, posing a scientific and engineering challenge comparable in significance and complexity to the Apollo moon-landing program of the 1960s and the Manhattan Project, from which the weapons originally came. Existing weapons must be kept safe and reliable far beyond their design lifetimes into the future, and they must be kept in this condition without further nuclear testing.
Maintaining safety and reliability
How shall we deal with this unprecedented challenge for the 21st century? The US Department of Energy (DoE), which has responsibility for US nuclear weapons, has begun the Stockpile Stewardship program, as directed by President Bill Clinton. The elements of Stockpile Stewardship are science, engineering, manufacturing, readiness, and, of course, good people. An integrated team composed of the DoE defense laboratories of Los Alamos (Los Alamos, NM), Lawrence Livermore (Livermore, CA), and Sandia (Albuquerque, NM), the Nevada Test Site, and the smaller, more-agile defense plants at Pantex, TX, Kansas City, MO, Oak Ridge, TN, and Savannah River, SC, can bring together the kind of people we need.
Stockpile Stewardship combines data from regular surveillance of existing weapons, archived data from past underground and aboveground nuclear tests, and previously unobtainable data from experiments performed in new, sophisticated facilities. This information must be tied together using advanced computer simulation and modeling capabilities now being developed in partnership with the private sector to assess the condition of the nuclear stockpile--its safety and reliability. Readiness to return to nuclear testing must also be maintained.
The ability of the weapons lab directors to certify the stockpile to the President, annually, today is largely based on the fact that the weapons are still mostly within their design lifetimes, also that test-experienced weapons designers and engineers are still working in the program. But both the people and the weapons are aging, making the scientific, engineering, manufacturing, and computing elements of Stockpile Stewardship central to continued confidence in the nuclear deterrent over time.
Weapons testing at NIF
A key testing facility, now under construction at Lawrence Livermore National Laboratory--the National Ignition Facility (NIF)--will house the world`s most advanced laser and will achieve fusion ignition in a laboratory for the first time in human history (see photo). NIF will be the world`s largest optical instrument, requiring three-quarters of an acre of high-precision optical surface area. This is 40 times the surface area of the Keck telescope in Hawaii, the world`s largest telescope.
With more than 3500 meter-scale optical components and 15,000 smaller-sized optical components being manufactured for the 192-beam laser in just over three years, NIF is bringing about a revolution in the US high-precision optics industry. NIF laser glass will be made via a continuous-pour method rather than in the batch process used in the past, for higher-quality glass at lower cost per unit. Larger machines, requiring fewer steps from start to finish, will be used for precision grinding and polishing operations. New 2-ft-diameter precision optical interferometers will bring unprecedented in-plant control of manufacturing processes on-line.
Stockpile Stewardship will benefit through higher-quality data thanks to private-sector innovations in manufacturing developed for NIF. Private-sector companies working on NIF are gaining knowledge that will result in better, cheaper non-defense-related products, such as flat-panel displays, instruments for controlling computer chip manufacture, and even ultraviolet-light-filtering windshields for automobiles.
Advanced experimental facilities such as NIF will provide the data to verify advanced computer codes that will come from the Accelerated Strategic Computing Initiative (ASCI). Computational capabilities must be increased by a factor of about one million because the problem of calculating aging effects inside a weapon is more difficult than designing the weapon in the first place. In designing a weapon, scientists can intentionally create symmetries that make calculating weapon performance easier. Aging processes such as corrosion or cracking violate these symmetries. Computer models must be able to handle three-dimensional problems with these additional or modified physical processes included.
New stewards needed
As facilities such as NIF and the computational modeling and simulation capabilities such as those under development in ASCI come into being, young scientists, engineers, and technicians must also develop skills and absorb experience and knowledge from their nuclear test-experienced mentors before they retire.
To attract the best people to Stockpile Stewardship, we must make them believe that the resources and facilities provided to do the job are equal to the task and worthy of serious commitment and hard work. When we partner with universities doing non-defense-related research in areas of serious scientific inquiry, young people working with advanced resources in advanced facilities develop skills that can be applied to solve complex problems such as wildfires, earthquakes, global warming, airline safety, drug design, and biomedical research. Stockpile Stewardship will attract some of these young people to the program, and they will bring with them their problem-solving skills.
The elements of a strong, secure future for our nation are tightly interwoven. More and more we see science and technology as rapidly changing interconnected areas of human endeavor. Technologies developed for the NIF laser may be useful in making better computer chips, which in turn makes the computational goals of Stockpile Stewardship more readily attainable. Better computational skills will put the USA at the forefront of information technology for the 21st century and also let us better assess the safety and reliability of our nuclear deterrent without further nuclear testing.
The safety and reliability of our stockpiled weapons finally rests on our willingness to provide the resources and facilities to ensure the success of our stewardship program. We must sustain this historic commitment, as we did the Apollo and Manhattan projects. o
The $1.2 billion National Ignition Facility, now under construction at Lawrence Livermore National Laboratory, is scheduled to start initial operations in 2001, with final construction to be complete in 2003.