A report prepared for Congress in December states that the National Ignition Campaign (NIC) did not meet its principal program goal to achieve ignition at the National Ignition Facility (NIF) by the close of FY 2012.
NIF is located at the Lawrence Livermore National Laboratory.
The report, written by the National Nuclear Security Administration (NNSA), is entitled, “NNSA’s Path Forward to Achieving Ignition in the Inertial Confinement Fusion Program." It notes, "The NIC made significant progress and brought the National Nuclear Security Administration (NNSA) closer than ever before to ignition in the laboratory."
"Present codes had predicted that NIF would attain ignition at the present scale. Since ignition was not achieved, this indicates significant gaps between experimental results, present models, and scientific understanding."
The disagreement between NIF experimental data and codes and models reflects an inadequate understanding of key physics issues required to make this determination. Plans are to move forward with a three year nationally-based program using NIF for a broad-based experimental program addressing a more diverse range of scientific issues and opportunities. The emphasis at the facility will shift towards improving computer models until they match up with what has been measured experimentally. Once the codes and models are improved to the point at which agreement is reached, NNSA will be able to determine whether and by what approach ignition can be achieved at the NIF. While that does not mean the end of ignition experiments, it does mean that more of the beam-time at NIF will be used to simulate nuclear weapons and for fundamental science, including some non-ignition work.
The plan allows for the development and testing of strategies to deal with problems that are identified.
After three years of work to better understand the physics of ignition, the NIF program will then be assessed again at the end of fiscal year 2015.
NNSA oversees management of the national laboratories for the Department of Energy.
NNSA, in the report, suggests that work on the giant laser at the Lawrence Livermore National Laboratory is critical to maintaining the nuclear stockpile. In particular, ongoing experiments are testing codes and models that underpin stockpile confidence, are providing fundamental scientific knowledge relevant to nuclear weapons, and are attracting and retaining the scientific talent required for NNSA’s broad national security missions. "Decreasing funding for the ignition program, or more broadly, NIF experiments in support of the NNSA weapons science program, would run counter to the long-standing judgment of the nuclear weapons policy community on the importance of maintaining scientific expertise in support of U.S. national security goals. It is imperative for the stockpile stewardship (SSP) to continue an ignition effort focused on improving the understanding of the science underlying ignition."
The report states that of the Inertial Confinement Fusion Program funds, about 20 percent directly go to ignition efforts. The actual costs of NIF and, more broadly, the ICF Program, are dominated by facility operations costs needed for all experiments.
Construction of NIF at the Lab was completed in March 2009. After a period of commissioning, initial experimentation, and diagnostics development, the first layered cryogenic target implosions were executed in September 2010. Over the next two years, the Lab has issued information that the NIF laser performed reliably and with great precision. Power and energy have exceeded initial design specifications.
The NASA report points out that to date there is no compelling scientific information suggesting that the approach used by NIF cannot achieve ignition. Because the approach has the closest relevance to nuclear weapons physics, this will remain the mainline approach for ignition either until it achieves ignition or until there is sufficient scientific understanding supporting a conclusion that priorities should be reset to favor an alternative approach.
In September 2012, the NNSA and the Lab proposed a plan that transitioned NIF to a national user facility. The plan puts into effect the transition from a focus on igntion to a NIF national user facility model, drawing broadly from the community for both the best scientific ideas and for peer review.
Among the proposals in the three year plan are efforts to continue a modified effort to pursue the present indirect drive approach to ignition; explore the physics revealed in experiments designed to evaluate integrated performance of the system; add a significant experimental effort to explore single physics effects and improved models; and explore alternative indirect drive approaches.
The report concluded that confidence in the present stockpile is dependent upon the data from a successful underground test program and a continued Stockpile Stewardship Program to understand the impact of any changes from the tested configuration. The gaps in understanding demonstrated by the ignition campaign are not at a level that would impact confidence in the stockpile. Rather the question is the extent to which NNSA will be able to rely upon codes and models as the basis for confidence in modifications and alterations, as NNSA extrapolates from as-tested configurations. Therefore, a program to resolve these gaps in the codes and models is vital.