Evaluation of Quantification of Margins and Uncertainties Methodology for Assessing and Certifying the Reliability of the Nuclear Stockpile
Summary
BACKGROUND
In order to meet their obligation to help maintain the capabilities of the nuclear weapons stockpile and to perform the annual assessment for the stockpile’s certification, the national security laboratories (Los Alamos National Laboratory—LANL, Lawrence Livermore National Laboratory—LLNL, and Sandia National Laboratories—SNL) of the National Nuclear Security Administration (NNSA) employ a wide range of processes, technologies, and expertise. The quantification of margins and uncertainties (QMU) framework plays a key role in helping to link those three elements. While it does not replace existing assessment methodologies, QMU makes a number of critical contributions. Concerns about its use, however, led the Congress to ask the National Research Council to evaluate 1) how the national security labs were using QMU, including any significant differences among the three labs; 2) its use in the annual assessment; and 3) whether the application of QMU to assess the proposed reliable replacement warhead (RRW) could reduce the likelihood of resuming underground nuclear testing.[1] This request was endorsed by the NNSA.
MAJOR FINDINGS AND RECOMMENDATIONS
QMU is a sound and valuable framework that helps the national security laboratories carry out the Department of Energy’s (DOE) responsibility to maintain the nation’s nuclear weapons capabilities. Its value is evident in many ways, including for the organization of the many stockpile stewardship tools such as the advanced simulation and computing codes and computing and for the allocation of important resources. The national security laboratories and NNSA should expand their use of QMU while continuing to develop, improve, and increase application of the methodology. While they have focused much attention on uncertainty quantification, a broader effort is needed in this area, including further development of the methodology to identify, aggregate, and propagate uncertainties. In a related issue, the identification of performance gates (see Glossary) and their margins is incomplete.
QMU also relies on expert judgment, and effective implementation of QMU will depend on maintaining a quality staff at the national security labs, particularly weapons designers. Finally, the national security labs are not taking full advantage of their own probabilistic risk assessment capabilities. Several probabilistic risk assessment concepts could be applied to QMU applications. In particular, the national security labs should investigate the probability of frequency (See Glossary) approach in presenting uncertainties.
The application of QMU in the annual assessment review conducted by the national security laboratories is growing and providing important insights, such as a basis for confidence in stockpile performance. Its use in the review is still limited, however, and should be expanded. In particular, margins (M) and uncertainties (U) should be reported for all gates that are judged to be critical for warhead performance.
While there are differences among the national security labs in how the QMU methodology is implemented, these differences can enhance the development of QMU. Different approaches for estimating uncertainties, for example, should continue to be explored. Differences in definitions and terminology, however, can inhibit communication and transparency, and the national security labs should agree upon a common set of definitions and terms. Consistency and transparency of the application of QMU are also being inhibited by the lack of documentation. Both NNSA and the labs should issue QMU guidance documents in time for the current assessment cycle.
QMU can be used to evaluate new warheads, such as the RRW design, and for certification. If the design of a new nuclear warhead is sufficiently “close” to existing tested designs, the new warhead could, in principle, be certified without nuclear tests, based on archival tests, modeling and simulation tools, and a more mature QMU methodology. The design labs (LANL and LLNL) should provide detailed justification for use of archival tests to support any proposed RRW design and investigate ways to help quantify “closeness”. Also essential for a credible RRW certification process are expanded peer review, documentation, and experimentation without nuclear testing.
[1] Throughout this report, the terms nuclear test and nuclear testing refer to nuclear explosions.
[A prepublication draft of the unclassified portion of this report by the National Research Council can be downloaded here.]
Too funny. I remember sitting in a meeting with some folks in X-Div in the 90s and bringing some of these concepts up. Was pooh-poohed out of the room. They had (still have?) a real not-invented-here mentality and an aversion to admitting to anyone (other than perhaps themselves) they don't understand something. It's too bad really, because some others might have some useful ideas and are willing to help. Oh well, that's LANL.
ReplyDeleteJust wait until some unexpected or completely overlooked event in the process rears its ugly head and all that fantasy QMU work goes right out the window.
ReplyDeleteThis remarks of "QMU" could essentially be shortened to: "The fact that nuclear testing has been used in the past to find a solution to a reliability problem does not mean that it was essential." (Richard L. Garwin in New York Times, Evidence Supporting Nuclear Tests Is Challenged, by William J. Broad, June 20, 1988.)
ReplyDeleteIn reality: "Over one-third of all nuclear-weapons designs introduced into our stockpile since 1958 have encountered reliability problems, and 75 percent of these were discovered and subsequently corrected thanks to actual explosive testing." (Then Secretary of Defense Caspar W. Weinberger in 1987, ibid.)
In reality, further: "Since 1958, 14 of the 41 weapon designs in the stockpile or 34 percent of the weapons have required post-development nuclear tests to resolve problems," and "In three-fourths of these cases, the problems were discovered as the result of nuclear tests, and additional tests were required to confirm that the fix was satisfactory." (Then Adm. Sylvester R. Foley in 1986, then Assistant Secretary for defense programs, ibid.)
U.S. urged to boost its nuclear vigilance
ReplyDeleteA bipartisan panel cites 'growing risks' that the world will see an attack. Biological terrorism is called the greatest threat.
By Cynthia Dizikes
December 4, 2008
Reporting from Washington -- President-elect Barack Obama will probably confront a biological or nuclear attack at home or abroad if the U.S. and its allies do not act decisively to prevent it, according to a report released this week by a panel created by Congress.
The report found that the U.S. had taken important steps to counteract nuclear proliferation and, to a lesser extent, biological terrorism, but had "not kept pace with growing risks."
The nine-member, bipartisan commission presented its conclusions Wednesday to Vice President-elect Joe Biden and Arizona Gov. Janet Napolitano, Obama's nominee for Homeland Security secretary.
"We have been losing ground, and we are less secure today than we have been in the recent past," said former Sen. Bob Graham (D-Fla.), the commission chairman.
The report concluded that biological agents posed the most imminent threat to the U.S. among weapons of mass destruction. The spread of biotechnology, and the corresponding rise of poorly secured and regulated pathogens around the world, has put the nation in an increasingly precarious situation, Graham said.
The Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism said American security was threatened by nuclear weapons programs in Iran and North Korea, as well as in Pakistan, given its history of political instability and arsenal of several dozen nuclear warheads.
"What we're saying in this report is: Look, this is urgent and important and it has to constantly be at the top of the menu," said former Sen. Jim Talent (R-Mo.), the commission's vice chairman.
The report, which was ordered by Congress last year to serve as a road map for the next administration, made several recommendations about reorganizing agencies to help slow the spread of nuclear weapons.
It also encouraged Obama to devote a White House official to coordinate intelligence and foreign policy to combat the spread of nuclear and biological weapons.
"There should be someone in the White House who wakes up every day, looks in the mirror and says, 'What do we need to do today to reduce the possibility of a weapon of mass destruction going off someplace in the world, specifically someplace in the United States?' " Graham said.
Graham said the person could play an important role in highlighting nonproliferation issues when the administration considered agreements such as the recent deal permitting U.S. sales of nuclear fuel and technology to India.
"There hasn't been someone who can stand up to the secretary of State or a secretary of Commerce or other Cabinet officials when the final decision is made," Graham said.
Obama has said that, as president, he would dramatically accelerate work to lock down nuclear material around the world.
A paper issued by his campaign in July said Obama would "appoint a deputy national security advisor to be in charge of coordinating all U.S. programs aimed at reducing the risk of nuclear terrorism and weapons proliferation."
Biden on Wednesday suggested the administration would follow the report's recommendations.
"We're not doing all we can to prevent the world's most lethal weapons from winding up in the hands of terrorists," Biden said. "This report is more than a warning about what we are doing wrong. It's a pragmatic blueprint for how to get it right."
But some specialists, and some officials in the Bush administration, cautioned against appointing too many advisors.
Homeland Security Secretary Michael Chertoff urged caution Wednesday, saying that the government risked creating too many extraneous layers of bureaucracy by creating "a czar to do this and a czar to do that."
"I put a big yellow light on, [a] go-slow, in terms of reorganizations," Chertoff said.
Dizikes is a writer in our Washington bureau.
cynthia.dizikes@latimes.com
This remarks of QMU could essentially be shortened to: "The fact that nuclear testing has been used in the past to find a solution to a reliability problem does not mean that it was essential." (Richard L. Garwin in New York Times, Evidence Supporting Nuclear Tests Is Challenged, by William J. Broad, June 20, 1988.)
ReplyDeleteIn reality: "Over one-third of all nuclear-weapons designs introduced into our stockpile since 1958 have encountered reliability problems, and 75 percent of these were discovered and subsequently corrected thanks to actual explosive testing." (Then Secretary of Defense Caspar W. Weinberger in 1987, ibid.)
In reality, further: "Since 1958, 14 of the 41 weapon designs in the stockpile or 34 percent of the weapons have required post-development nuclear tests to resolve problems," and "In three-fourths of these cases, the problems were discovered as the result of nuclear tests, and additional tests were required to confirm that the fix was satisfactory." (Then Adm. Sylvester R. Foley in 1986, then Assistant Secretary for defense programs, ibid.)
(QMU is political correctness of nuclear testing.)