Stockpile stewardship in the light of national ignition campaign experience

ABSTRACT

Uncontrolled risk is inherent in any program that lacks a proven means for revealing improper system performance, and the U.S. Stockpile Stewardship Program (SSP) is no exception. The downside of uncontrolled risk has been illustrated by the outcome of the National Ignition Campaign (NIC), a part of the Inertial Confinement Fusion (ICF) Program that has long been characterized as a crucial adjunct to the U.S. nuclear weapons program. For most of its duration, the NIC utilized simulations and partial-system experiments at several facilities, adding full-system experiments at the National Ignition Facility (NIF) only at the very end of the program. Uncontrolled risk was present in the program while those experiments were absent. That risk materialized when failure to achieve fusion capsule ignition was repeatedly and conclusively demonstrated in full-system experiments. For the SSP, the corresponding risk is that expectations concerning the safety, performance, and reliability of weapons in the stockpile are significantly incorrect. The only proven way of controlling that risk—finding out whether the expectations are wrong—requires nuclear testing. In its absence, this risk is not controlled by the SSP. The ongoing presence of uncontrolled risk in the U.S. nuclear stockpile leads inevitably to uncertainty in the effectiveness of the U.S. nuclear deterrent. None of the potential consequences of that uncertainty, one of which is a decrease in the deterrent's effectiveness, are beneficial to the United States or those who rely on its nuclear umbrella.

Acknowledgments

For comments and encouragement that have significantly improved this paper, we give our sincere thanks to Peter Adams, Stephen Becker, Mark Chadwick, Baolian Cheng, Clay Dillingham, John S. Foster, Jr., Damon Giovanelli, James Glimm, Joyce Guzik, Marie Harper, Terry Hawkins, Siegfried S. Hecker, John Hopkins, John Immele, Arthur Kerman, Robert Kuckuck, James Langenbrunner, Craig Leasure, Glenn Mara, Fred Mortensen, Charles Nakhleh, John Pedicini, C. Paul Robinson, John Scott, Robert Selden, Jonathan Ventura, and Gary Wall. We would also like to thank Edward Conard for reviewing and commenting on section 3.2.

Notes on contributors

David H. Sharp ([email protected]) is a laboratory fellow (retired) and guest scientist at Los Alamos National Laboratory. He has served as leader of the Complex Systems Group and as chief scientist in the Science, Technology and Engineering Directorate at Los Alamos. Sharp is a graduate of Princeton University (AB, 1960) and the California Institute of Technology (PhD, 1964). His recent scientific work has focused on problems that arise in predicting, accurately and reliably, the behavior of complex systems. Sharp is a fellow of the American Association for the Advancement of Science, the American Physical Society, and the Society for Industrial and Applied Mathematics. He is currently a consultant to the Department of Mechanical Engineering, Stanford University, and the Department of Ecology and Evolution at the University of Chicago.

Merri M. Wood-Schultz ([email protected]) earned a PhD in physics from the Georgia Institute of Technology. During her full-time professional career as a technical staff member and then a fellow of Los Alamos National Laboratory (LANL), her work included the prediction and post-shot analysis of data acquired in nuclear tests and above-ground experiments (AGEX) for the purposes of weapons development, weapons physics, and stockpile support, including yield certification. She is currently a guest scientist and retired fellow of LANL, and she is employed part-time as a member of a scientific advisory panel for the U.S. government.

Notes

1. A pertinent statement can be found on page 19 of “Science Based Stockpile Stewardship,” Jason Report JSR-94-345, The MITRE Corp., McLean, Va., November 1994: “These non-proliferation principles provide the framework which must govern the stewardship program. The weapons physics and diagnostics program should consist of a core activity which maintains confidence in the present stockpile for the foreseeable future to standards not substantially different from those maintained when underground nuclear tests were permitted.”

2. D. H. Sharp, “Nuclear Testing: Deterrence, Stewardship, and Arms Reduction,” Comparative Strategy, vol. 29 (2010): 300–301.

3. U.S. Department of State, Fact Sheet, Bureau of Arms Control, Verification and Compliance, “Maintaining the US Nuclear Weapons Stockpile in the Absence of Nuclear Explosive Testing,” September 28, 2012, https://2009-2017.state.gov/t/avc/rls/198238.htm

4. National Academy of Sciences, “The Comprehensive Nuclear Test Ban Treaty: Technical Issues for the United States,” Washington, DC: The National Academies Press, 2012.

5. There is often a significant discrepancy between the output of a code and the experimental data to which it is compared. Parameters and physical models implemented in the code are sometimes adjusted to eliminate or reduce the discrepancy; this procedure is called code calibration. Note that a code that has been calibrated can, at best, only be regarded as partially validated. Indeed, it is because validation of some predictions of the code has failed that it must be calibrated. Code calibration is not always obtainable, and even when satisfactory calibration is obtained, the degree to which such calibration will persist if experimental conditions are changed can itself be determined only with the help of experiments. For further discussion, see M. M. Wood-Schultz and D. H. Sharp, “Persistence of Calibration in a Physics Simulation,” in Proceedings of the Nuclear Explosives Code Development Conference, 2010, LA-UR-11-01426, [email protected]

6. In his 1987 testimony before the Senate Armed Services Committee on technical aspects of the TTBT, [6] Dr. Hecker makes the following statements: (1) “Nuclear testing continues to be an indispensable part of the design process because of the great complexities of nuclear weapons behavior, which cannot be completely modeled by computer nor adequately explored by non-nuclear laboratory experiments”; (2) “As long as…we continue to be asked…to be responsible for weapons already part of the deterrent force, we will need nuclear tests”; (3) “Restrictions, including the present ones, on our ability to test these complex devices carry technological risks. These technological risks may translate into military risks, or at least military penalties. I consider it my responsibility to bring these technological risks to your attention”; and (4) “ Testing constraints more restrictive than those in the TTBT would greatly endanger our ability to adequately support the Nation's deterrent in terms of safe, secure, reliable and effective nuclear weapons.” Statement of S. S. Hecker before the Senate Armed Services Committee concerning TTBT and PNET Ratification, February 26, 1987. This statement, co-authored with D. R. Westervelt, also appears as a CNSS Brief, Los Alamos National Laboratory (LANL), dated April 8, 1987. This document is available from the LANL Library, [email protected]

7. Sharp, “Nuclear Testing,” 302.

8. Sharp, “Nuclear Testing,” 303.

9. J. Lindl, “The Development of Indirect Drive ICF and the Countdown to Ignition Experiments on the NIF,”, Maxwell Prize Address, American Physical Society Division of Plasma Physics Meeting, Orlando, FL, November 15, 2007, available at fire.pppl.gov/aps07_lindl_maxwell.pdf

10. J. Lindl, P. Amendt, et al., “The Physics Basis for Ignition Using Indirect-Drive Targets on the National Ignition Facility, Physics of Plasmas, vol.11 (2004): 339–491; S. W. Haan, P. Amendt, et al., “Design and Simulations of Indirect Drive Ignition Targets for NIF,” Nuclear Fusion, vol.44 (2004): 171–176; Report on the Workshop on High Energy Density Physics, Gaithersburg, MD, May 24–26, 2004, https://ifeworkshop.llnl.gov/HEDP_Task_Force_Report.pdf. Opinions about ignition at NIF prevailing in 2004 are reflected in statements such as “It (NIF) is predicted to achieve ignition in both indirect drive…and direct drive illumination,” “The imminent achievement of ignition on the NIF…” and “ignition is expected to be achieved on NIF in less than 10 years…” (reported in ibid., 71 and 73).

11. Editorial, “Ignition Switch,” Nature, vol. 491 (2012): 159; G. Brumfiel, “Laser Lab Shifts Focus to Warheads,” Nature, vol. 491 (2012): 170–171, 2012; U.S. Department of Energy, “ICF Execs Draft to Congress for NNSA,” October 2012, LA-UR-12-25242.

12. National Academy of Sciences, “Review of the Department of Energy's Inertial Confinement Fusion Program,” Washington, DC: The National Academies Press, 1997.

13. Sharp, “Nuclear Testing,” 296.

14. The discussion in this section draws heavily on Edward Conard, “Unintended Consequences: Why Everything You've Been Told about the Economy Is Wrong” (New York: Portfolio/Penguin, 2012).

15. Freddie Mac's senior vice president in charge of its affordable housing mission admitted that the higher default rates typical of lower-quality affordable mortgages could do “serious harm to households and neighborhoods.” This grim reality notwithstanding, [the executive concluded] “tipping the scale in favor of no cap on defaults at this time was the pragmatic consideration…[because failing to do so] would be interpreted by external critics as additional proof that we are not really committed to affordable lending” (quoted in Conard, “Unintended,” 178).

16. H. T. Hawkins, “Maintaining Nuclear Stability during Times of Transition. Still Required: Thinking about the Unthinkable,” LA-UR-08-05902, [email protected]

17. D. Sharp and M. Wood-Schultz, “Nuclear Stockpile: Concern over US Nuclear Stewardship,” Nature, vol. 493 (2013): 608.

18. Lindl, “The Development”; DOE statement; Lindl et al., The Physics”; Haan et al., “Design and Simulations”; Report on the Workshop on High Energy Density Physics.

19. “Science Based Stockpile Stewardship.”

20. NNSA press release available at http://www.nnsa.energy.gov/mediaroom/pressreleases/20th-anniversary-ssp-commitment

21. Concerning the CTBT, see (1) statement by President Clinton; “I consider the maintenance of a safe and reliable nuclear stockpile to be a supreme national interest of the United States. I am assured…that we can meet the challenge of maintaining our nuclear deterrent under a CTBT,” “Statement on a Comprehensive Nuclear Weapons Test Ban,” August 11, 1995, https://www.gpo.gov/fdsys/pkg/WCPD-1995-08-14/pdf/WCPD-1995-08-14-Pg1432-2.pdf; and (2) statement by President Obama, referring to nuclear weapons, “As long as these weapons exist, the United States will maintain a safe, secure and effective arsenal to deter any adversary and guarantee that defense to our allies,” “Obama Prague Speech on Nuclear Weapons,” April 5, 2009, http://www.huffingtonpost.com/2009/04/05/obama-prague-speech-on-nu_n_183219.html

Additional information

Notes on contributors

David H. Sharp

David H. Sharp ([email protected]) is a laboratory fellow (retired) and guest scientist at Los Alamos National Laboratory. He has served as leader of the Complex Systems Group and as chief scientist in the Science, Technology and Engineering Directorate at Los Alamos. Sharp is a graduate of Princeton University (AB, 1960) and the California Institute of Technology (PhD, 1964). His recent scientific work has focused on problems that arise in predicting, accurately and reliably, the behavior of complex systems. Sharp is a fellow of the American Association for the Advancement of Science, the American Physical Society, and the Society for Industrial and Applied Mathematics. He is currently a consultant to the Department of Mechanical Engineering, Stanford University, and the Department of Ecology and Evolution at the University of Chicago.

Merri M. Wood-Schultz

Merri M. Wood-Schultz ([email protected]) earned a PhD in physics from the Georgia Institute of Technology. During her full-time professional career as a technical staff member and then a fellow of Los Alamos National Laboratory (LANL), her work included the prediction and post-shot analysis of data acquired in nuclear tests and above-ground experiments (AGEX) for the purposes of weapons development, weapons physics, and stockpile support, including yield certification. She is currently a guest scientist and retired fellow of LANL, and she is employed part-time as a member of a scientific advisory panel for the U.S. government.