Heraclitus, QMU, and Laser Fusion

Heraclitus had many famous quotes, but the one I often remember is, “No man ever steps in the same river twice. For it’s not the same river and he’s not the same man.” My take away from this is relevant to many of the complex problems I have worked with over my 50 odd years of dealing with various science and technology problems. Also, I can claim without contradiction that my career has never been blemished with even a single success.

For some reason, I always seemed to be interested in really challenging problems that were limited by not just engineering and physics, but also by constraints of politics, economics, and human decision making. I have written about this general class of problems that are best described as “wicked.” They are characterized as not having any closed form solution. Working on such problems provides the participants with alternating experiences of euphoria and utter depression. Maybe that is why poor Heraclitus had a problem crossing a river.

People in charge of maintaining the United States’ nuclear weapons stockpile are facing a particularly wicked problem. Their job is to assure that the weapons are safe, secure, and reliable… but without the ability to fully test them by detonating any of these weapons. This approach is called Quantification of Margins and Uncertainty (QMU).  It is a process of highly diagnosed but sub critical experiments and comprehensive computer simulations to allow decision making about the risk involved in the performance and reliability of the stockpile.

An extremely important and challenging aspect of this program is the use of lasers to ignite fusion ignition in the laboratory. The recent experiment at the National Ignition Facility (NIF) recently demonstrated fusion ignition with more energy output than delivered to the target by the lasers. This is the first time that actual “fusion ignition” has been achieved in a lab.

In my Feb.23 post “Fusion Fact or Fiction,” I explained the seemingly “miraculous” achievement involving many tradeoffs on nonlinear variables adjusted over years of complex experiments and calculations requiring continuing political support with ever-increasing budgets. I stated then (and as far as I know now) the achievement has yet to be repeated. The lab director explained recently, “We haven’t had the kind of perfect capsule that we had in December.” Perfect capsules will require a “perfect” budget.

An additional issue is the performance of the laser. Pushing the laser to its limits causes damage to the optical system that is expensive and time consuming to fix. There is also the political pressure created by the association of fusion research with the desire to develop the ultimate clean, cheap, unlimited source of energy.  

So, how can leaders deal with this wicked problem? I think the methodology that will be useful is QMU that focuses on establishing the needed margins of performance of all the components of NIF experiments that will have uncertain outcomes. Each experiment will be a different man stepping into a different river.  Heraclitus would certainly get his feet wet, but he might get swept away.

8 thoughts on “Heraclitus, QMU, and Laser Fusion

  1. Gene McCall

    Their definition of a perfect capsule is simply wrong. The “ignition “ shot was simply less of a failure than earlier shots. Yield should have been at least 5 times higher. It is the grain size that matters.

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  2. Al Toepfer

    “Success is the ability to go from one failure to another with no loss of enthusiasm, maintain your passion.” Winston Churchill

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  3. Al Toepfer

    Is AI the tool for using QMU?
    https://www.foreignaffairs.com/united-states/eric-schmidt-innovation-power-technology-geopolitics
    “Artificial intelligence will change the very nature of scientific research. Instead of making progress one study at a time, scientists will discover the answers to age-old questions by analyzing massive data sets, freeing the world’s smartest minds to devote more time to developing new ideas. As a foundational technology, AI will be critical in the race for innovation power, lying behind countless future developments in drug discovery, gene therapy, material science, and clean energy—and in AI itself.”

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  4. Steve Goldstein

    In addition to the scientific method requirement of independent peer review, a basic tenet has been that experiments ought to be repeatable, not only by the institution reporting the research but also perhaps an independent group (the latter, however, unlikely for ICF ignition due to phenomenal budget constraints). Is the thesis here that somehow QMU removes the age-old requirement of repeatability? Should the community accept that?

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    1. gyonas

      Should require repeated results in many simple experiments, but some very complex phenomena are extremely variable, so QMU
      gives a rigorous method for evaluation.

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  5. albuquerqueal

    Thanks for the reference to the QMU and Nukes report. QMU appears to be an advanced version of Quantitative Risk Analysis that takes advantage of modern computational capabilities. It seems to me that it is QRA on steroids.

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