C. BRUCE TARTER and E. MICHAEL CAMPBELL
The signed editorial in September's Laser Focus World advocating the termination of the National Ignition Facility (NIF) project was inaccurate and misleading. Furthermore, the editorial makes no reference to the six reviews since 1990 by panels of independent scientific experts. Each publicly available report recommended that the government proceed with the NIF; one panel felt so strongly that it said, "The NIF is without question the most scientifically valuable of the programs proposed for the SBSS [Science-Based Stockpile Stewardship]."1
The NIF, being designed, built, and operated by a team from Lawrence Livermore, Los Alamos, and Sandia National Laboratories and the University of Rochester, will contain the world's largest laser, a research tool allowing scientists to create, on Earth, fusion ignition and the temperatures and pressures at the center of the Sun or of an exploding nuclear weapon (see figure). The NIF will focus 192 extremely powerful laser beams onto a BB-sized capsule of deuterium and tritium, forcing the two heavy isotopes of hydrogen to combine through compression and heating, producing fusion ignition, that is, self-sustained fusion burn. The conditions the NIF creates will be unique on Earth and will have a major impact on national security as well as corollary benefits for fusion energy and basic science.
The NIF is a cornerstone of the Stockpile Stewardship and Management Program of the Department of Energy, which responds to a request by the President and Congress to provide a means for maintaining confidence in our nuclear deterrent and for sustaining our core nuclear weapons expertise, in the absence of nuclear testing. The President has signed the Comprehensive Test Ban Treaty (CTBT). The Director of the Arms Control and Disarmament Agency and such arms control advocates as Prof. Henry Kendall of MIT have stated that the stockpile stewardship program, including the NIF, is needed under the CTBT.2 These recommendations stand in stark contrast to the editorial`s suggestion that once the treaty is ratified, the United States should abandon the technical means of verifying nuclear weapons safety and reliability.
Weapons physics and fusion energy
The NIF, with 40 times the energy and 10 times the power of the existing Nova laser, will produce, on a tiny but large enough scale, temperatures and pressures that occur in nuclear weapons explosions. And it will be used to study fusion ignition. Scientists will use NIF data from both ignition and non-ignition experiments to better understand the effect of changes that occur due to weapons aging or re-manufacture—studies that Nova can not complete due to its smaller energy. NIF data will resolve specific weapons physics problems likely to arise and will help verify advanced computer codes used to assess weapon reliability. It is important to note that Britain and France have included major high-intensity laser capabilities in their weapons stewardship efforts.
Important fusion energy questions will also be answered. The NIF is likely to achieve fusion ignition and energy gain for the first time in a laboratory. The first independent groups to recommend proceeding with an ignition facility like the NIF were the National Academy of Sciences and the Fusion Policy Advisory Committee in 1990.3,4 The Inertial Confinement Fusion Advisory Committee reviewed ICF and the NIF from 1992 to 1996 and also recommended proceeding with the NIF.5 Proving that more energy can be produced than is used to create ignition will lay the scientific foundation for future commercial fusion power production. Note that the world spends more than $600 billion per year on electricity production today.6
Tool for astrophysics research
Because the NIF will also be able to reproduce conditions that exist in stars and the sun, even without ignition, it will become an important new tool for laboratory astrophysics. At a recent workshop on laboratory astrophysics, scientists from around the world showed their important Nova results and highlighted the increased value of NIF capabilities. The NIF's impact on the leading edge of high-energy-density physics will be unparalleled. These scientific advances will, in turn, have a significant impact on weapons and fusion energy issues.
Additionally, the NIF's $900million of private-sector contracts will "push the envelope" for industrial partners in several high-technology segments of the economy. Technical and manufacturing process advances will accrue to firms in precision optics, laser and electro-optics technologies, high-speed instrumentation, micro-fabrication, and advanced imaging. Commercial areas already positively affected include advanced manufacturing techniques, advanced cost-effective health-care technologies, extreme-ultraviolet lithography for more-powerful computer chips, and micropower impulse radar, licensed by 25 companies for a variety of near-term applications.
The NIF project began in 1996 and will start initial operations in 2001 with final construction complete in 2003. The project has met all milestones. The project reviews continue; the reviewers continue to hear all issues, and they continue to recommend proceeding. Specifically, the NIF was reviewed a second time by the JASON group (academic scientists consulted by the Department of Defense and the Department of Energy in matters of national security) in 19967 and again in 1997 by the National Research Council of the National Academy of Sciences.8 Assuming the FY1998 funding bill, now completed by Congress, is signed by the President in its present form, Congress and the administration will have committed $500 million to the NIF of its total $1.2 billion bill. This continued level of endorsement and bipartisan support underscores the recognized importance of the NIF to the United States.
The weapons stockpile continues to age; by 2005, most weapons will reach the end of their designed lifetime. Because there is no experience with very old nuclear weapons, we do not yet know how difficult certifying their safety and reliability will be. In this circumstance, our task must be to give the country the tools it needs to make the best technical judgments.
REFERENCES
1. "Science Based Stockpile Stewardship," S. Drell, SLAC, Chair, JASON, JSR-94-345, MITRE Corp. (Nov. 1994).
2. See, for example, "Taking care of nuclear weapons," H. Bethe, H. Kendall, and H. York, San Jose Mercury News, May 25, 1997.
3. "Second Review of the Department of Energy`s Inertial Confinement Fusion Program Final Report," S. Koonin, Caltech, Chair, National Academy Press (Sept. 1990).
4. "Fusion Policy Advisory Committee Final Report," G. Stever, NAE, Chair, DoE (Sept. 1990).
5. Letter report of the Inertial Confinement Fusion Advisory Committee to V. Reis from V. Narayanamurti, College of Engineering, UCSB, February 21, 1996.
6. Energy from Inertial Fusion, International Atomic Energy Agency, Vienna, Austria (1995).
7. "Inertial Confinement Fusion (ICF) Review", D. Hammer, Cornell University, Chair, JASON, JSR-96-300, MITRE Corp. (Feb. 1996).
8. "Review of the Department of Energy`s Inertial Confinement Fusion Program, The National Ignition Facility," NAS/NRC, Washington, DC (1997).
C. Bruce Tarter is director and E. Michael Campbell is associate director of Laser Programs at Lawrence Livermore National Laboratory, Livermore, CA 94551.