First Experimental Zero-knowledge

Already back in July, at the 2015 INMM Annual Conference, we reported initial results from the first zero-knowledge differential neutron radiographic measurements. To our knowledge, this was the first demonstration of a physical zero-knowledge proof of physical properties. This proof-of-concept constitutes a small but important first step toward an efficient zero-knowledge protocol for nuclear warhead authentication where sensitive information is never measured.

For this first demonstration, we tried to implemented all key steps of a zero-knowledge inspection using 14-MeV DT neutron radiography with test items represented by patterns of steel and aluminum cubes. We were able to preload the bubble detectors with the complement of the radiograph of a reference item and, by subsequent irradiation, verify whether items presented for inspection were identical to the reference item or not. We confirmed that the results yielded “zero information” when valid items were tested and successfully identified tampered items for four different diversion scenarios.

Watch this space for updates as we evaluate new measurements and write up the journal version of the paper.

After the Iran Nuclear Deal: Multinational Uranium Enrichment

In April 2015, Iran and the E3+3 nations negotiated a framework for a “comprehensive solution that will ensure the exclusively peaceful nature of the Iranian nuclear program.” The final settlement, expected by July 2015 or soon after, would constrain Iran’s activities for various extended periods in return for the lifting of sanctions and affirm Iran’s right to pursue its nuclear program free of the limits on its uranium enrichment capacity a decade or more from now. What happens when these restrictions begin to phase out?

In our recent Science Perspective piece, we outline one approach to limit the long-term risk by using the next 10 years to convert Iran’s national enrichment plant into a multinational one, possibly including as partners some of Iran’s neighbors and one or more of the E3+3 countries.

The full article (PDF) is available here.

WANTED: PhD Students, 2014-2015

NOTE: Deadlines are December 15, 2014 (MAE) and December 1, 2014 (WWS)

The Nuclearfutures Laboratory has openings for graduate students interested in studying interdisciplinary problems related to nuclear energy, nuclear nonproliferation, and nuclear disarmament verification. Students interested in pursuing a doctoral degree through the Nuclearfutures Laboratory can either apply for a PhD program in the Department of Mechanical and Aerospace Engineering (MAE) or for a PhD program in the Woodrow Wilson School of Public and International Affairs (WWS/STEP).

Here is a summary of our current areas of research:

Nuclear Disarmament Verification. Our research focuses on new concepts and technologies that can help support verification approaches for nuclear disarmament in two main areas: the treatment of fissile materials in future arms-control regimes and the verification of nuclear warheads slated for dismantlement. We are also part of the new Consortium for Verification Technology and PhD projects could involve internships at a U.S. National Laboratory.

Research on disarmament verification places a strong emphasis on warhead counting and on verified nuclear warhead dismantlement, which might become necessary for deep-cuts arms control regimes. We pursue several technical approaches in this area. Our work combines neutron physics, computer modeling, and experimental work at the Princeton Plasma Physics Laboratory (PPPL).

Nuclear Power. Our research explores the shapes of alternative nuclear futures looking in particular at emerging technologies, many still in the R&D stage, that may be potential game changers for nuclear power. The main emphasis is currently on analyzing and assessing proposed small modular reactor (SMR) designs, which are potentially better suited for a modern electric grid with more distributed power generation and could also offer increased safety and security through underground siting. Some designs also envision much longer core-lives and promise lower proliferation risks.

Please write to Alexander Glaser if you have questions about admission procedures, the Laboratory’s activities and possible topics for a thesis.

Memo on the Potential Value of Stricter Limits on Iran’s Stockpile of Low-enriched UF6

In the negotiation over Iran’s nuclear program there currently appears to be an unbridgeable gap between Iran’s minimum requirement for enrichment capacity, the equivalent of the approximately 10,000 IR-1 centrifuges currently operating at Natanz, and the U.S. upper limit, which appears to be considerably lower. But there is another variable which also determines how quickly Iran could produce enough 90% enriched uranium for a nuclear explosive if it broke its commitment to stay below 5% enrichment. This variable is the size of Iran’s stockpile of up-to-5%-enriched uranium. Having a large stockpile of low-enriched uranium to feed into its centrifuge cascades shortens by a factor of three, e.g. from six to two months, the time that it would take to produce enough 90% enriched uranium for a bomb.

In this memo, first circulated in late September, Frank von Hippel and Alex Glaser show that it would be possible to reduce Iran’s current stockpile of 5,000 kg of low-enriched UF6 to about 200 kg made possible by using a smaller (12-inch) cylinder for enriched uranium. This would make it possible to recover the factor of three in breakout time and might make it possible for the P5+1 to raise their upper limit on Iran’s centrifuge capacity.

Unmaking the Bomb. The Book.

ceip-launchOur book is finally out, and we had the opportunity to present it yesterday at the Carnegie Endowment for International Peace in Washington, DC. Our argument is based on a very simple premise: Banning nuclear weapons will not end the threat of nuclear war and nuclear explosions if countries continue to make, stockpile, and use the fissile materials that make nuclear weapons possible. International efforts to abolish nuclear weapons and to prevent proliferation and nuclear terrorism so far have been acting largely in parallel with no comprehensive underlying strategy. With now enough fissile material around for about 200,000 nuclear weapons, we propose a new framework that puts these materials front and center. We propose a set of policies to drastically reduce fissile material inventories worldwide with a view to their total elimination as irreversibly as possible. Put simply, no material, no problem.

The slides of the briefing are available here.

Radical Reactors, Part 1

NFL-mask-msre Molten salt reactors (MSRs) are often advocated as a radical but worthwhile alternative to traditional reactor concepts based on solid fuels. In a paper published in the Annals of Nuclear Energy in January 2015, Ali Ahmad, Edward McClamrock and Alexander Glaser study the resource requirements and proliferation-risk attributes of denatured molten salt reactors.

The analysis presented in the paper confirms that MSRs could offer significant advantages with regard to resource efficiency compared to conventional thermal reactors based on light-water reactor technology. Depending on specific design choices, even fully denatured reactors could reduce uranium and enrichment requirements by approximately a factor of 3–4, even when operated on an open fuel cycle. As for the implications associated with proliferation risk, fully denatured single-fluid reactors using low-enriched make-up fuel appear as the most promising candidate technology minimizing overall proliferation risks and should, in our view, therefore receive particular attention despite being less attractive from the perspective of resource utilization.

Nature Article on Nuclear Warhead Verification

We have put together a webpage summarizing the main challenges of nuclear disarmament verification and the concept of the template approach for warhead authentication, which is the basis for the Nature article from June 2014. The page also provides a brief overview of other verification projects currently underway and includes a list of useful readings.

Note also the story on the article in Science.

Nuclear Transparency Scorecard

Zia Mian and Alex Glaser presented at the 2014 NPT Prepcom in New York on behalf of the International Panel on Fissile Materials on next steps the nuclear weapons states can take to increase transparency of their nuclear weapon and fissile material stockpiles as part of meeting their obligations under the NPT 2010 “Action Plan on Nuclear Disarmament.”

The presentation (PDF) was co-sponsored by the Missions of the Netherlands and of Japan, represented by Ambassador Henk Cor van der Kwast of the Netherlands and Ambassador Toshio Sano of Japan.

Iran 2014: Aiming for the Best of Imperfect Outcomes

Throughout Robert Einhorn’s report, “Preventing a Nuclear-Armed Iran,” Einhorn consistently reminds us about of the necessity of compromise and trade-offs during the ongoing 2014 negotiations toward a comprehensive nuclear agreement with Iran.

Einhorn begins by outlining the components of an ideal comprehensive agreement, highlighting three goals: (1) Ensuring and enabling early detection of breakout (2) Lengthening the breakout timeline (by reducing Iran’s capability—its enrichment levels and centrifuge numbers—such that it does not have enough time to produce sufficient fissile material before outside intervention) (3) Outlining a strong international response to breakout, which would provide effective deterrence.

Einhorn then goes on to discuss the feasibility of such an ideal agreement being reached. He admits several reasons to be skeptical about the success of these talks. First, he clarifies that the possibility of Iran breaking out is a real danger, pointing out that the debate about preventing Iran from acquiring a nuclear weapon versus developing the capability to develop a weapon is a myth; in fact, Iran already has the capability. Due to Iran’s persistent claims of a peaceful, scientific purpose, Supreme Leader Khamenei’s 2005 fatwa against nuclear weapon possession, and a lack of complete inspection information, Einhorn admits that we likely cannot ever expect to eliminate Iran’s capability or dismantle its enrichment facilities—the ideal U.S. outcome. He also recognizes that the U.S. will likely have to take a more conciliatory stance during talks, compromising on some of its goals and easing sanctions in exchange for reductions in Iran’s nuclear program. Inevitably, the negotiations will also be stalled and bombarded by strong and conflicting opinions from parties vying for different demands; some parties, like Israel, will likely only be appeased by unrealistically substantial concessions by Iran. Thus, negative press and backlash to the final agreement seems inevitable.

However, there are also reasons to be hopeful. Beginning with the negotiations for the Nov. 2013 Joint Plan of Action, Iran has been the most willing it has been in many years to come to the negotiating table. Unlike its previous non-compliance with IAEA regulations and inspections, the IAEA confirmed that Iran has indeed complied with the JPA’s reduction requirements, which lengthen the breakout timeline by a few months, and monitoring requirements. Iran’s newfound willingness to join talks was perhaps ushered in by the more moderate leadership of President Rouhani. Rouhani belongs to the camp of Iranian politicians who believe that the U.S. and Iran do have some overlapping interests, and has prioritized Iran’s economic improvement (starting with the lifting of sanctions). The JPA, while a temporary and incomplete solution, demonstrates an unprecedented level of diplomacy between Iran and the P5+1. Examining the progress through the JPA, Einhorn seems to suggest that appealing to Iran’s domestic priorities (such as its emphasis on developing a civil program, for which they would only need a portion of their current capacity, and its economy) may be an effective diplomatic strategy.

Given these factors, I pose to you a few questions:

  1. What are your predictions for the outcome of these 2014 talks? i.e. length of the talks, an extension of the JPA vs. a comprehensive agreement, which parties are dissenters or compromisers, public opinion/reaction
  2. Which of the three goals listed above (in the second paragraph) do you think the U.S. and P5+1 should prioritize and refuse to yield on for the final, comprehensive agreement? Which element is most important in preventing a nuclear-armed Iran? The most feasible to accomplish?
  3. Do you consider recent developments in negotiations with Iran, specifically the 2013 JPA, a success or failure?
  4. How should the U.S. and P5+1 go about appealing to Iran’s domestic agenda? What are Iran’s largest domestic considerations?


Credible Commitment: in Iran and in the NPT

One of the largest problems in attempts to work towards international non-proliferation is the lack of credible commitment, spurring the concern that other nations will be acting outside of agreements and skirting verification. This fear tends to undermine efforts of the Nuclear Non-Proliferation Treaty, and it certainly surfaces when discussing Iran’s nuclear research and enrichment programs.

When we examined the IAEA report on Iran for one of our problem sets, we saw that Iran was operating an underground enrichment plant that had previously gone unnoticed. Given the fact that this plant was producing up to 20% HEU, it caused a significant ripple of concern at the time of the report. Could this present an obstacle to future agreements concerning nuclear enrichment in Iran? As Einhorn writes in his report, Iran already has the technological know-how and hands-on experience to produce weapons grade uranium, and theoretically produce nuclear weapons. At this time, the United States Intelligence Community, or IC as Einhorn calls it, is uncertain whether Iran intends to pursue nuclear weapons as part of their nuclear program. This could present a problem when examining the practical needs of Iran from multiple nations’ perspectives. A nation like Israel likely does not believe that Iran needs a nuclear weapon (as they strongly oppose Iran’s possession of a weapon), and thus might limit its view of Iran’s practical needs to nuclear power, or even less nuclear activity. Conversely, Iran might include eventual potential development of a nuclear weapon in its practical needs. Even if an agreement were to be reached preventing Iran from developing a nuclear weapon at the moment, would credible commitment problems arise due to Iran’s past operation of an unknown nuclear facility? What kinds of verification techniques would the European Union and the P5+1 states require of Iran, and what would Iran consent to?

Additionally, if this credible commitment problem indeed exists regarding Iran, how would this affect the state and stability of the NPT? It was mentioned in class that, after North Korea’s exit from the NPT, a stable agreement in Iran would contribute to the strength of the NPT’s agreement. Would a failure to complete an agreement in Iran before the JPA expires signal a shift downward in the power of the NPT? Might other states decide to leave the NPT and pursue nuclear programs? What kind of commitment problem exists with the NPT, and how might it be fixed? — Nicole

On the Iran Nuclear Crisis (II)

The Brookings Institute’s recent paper in the Arms Control and Non-Proliferation Series covers many of the current concerns involved with Iran’s nuclear programs, as well as relevant history. Of the many elements recommended for a comprehensive and effective agreement, some aspects of the recommendation seem unfortunately hard to realize.

One aspect is the need for strong international response, particularly the timing elements associated with the non-military actions. While I can see how the initial diplomatic and non-military approaches tend to take a lot of time (many months) and how this would be a factor in Iran’s possible breakout decision, it seems impossible to find and implement a concrete answer to this element. It seems difficult logistically to go through those current structures and authorities to try to build an official commitment of what actions it would take, and within what amount of time, at this international level since this would be just for one country. Actually defining and putting into place such a timeline could be problematic; on one hand, while this process will bring forth a more defined articulation and public commitment for how the diplomatic and non-military approaches would work towards preventing the breakout, it would also be clarifying for Iran, and not just those wishing to prevent Iran’s breakout possibilities. In as much as the international level policies and decisions are transparent, it may be impossible and even problematic to articulate and specify these possible approaches. In the end, this aspect does seem quite difficult to resolve, in terms of the more “key” goal of making it unclear for Iran to calculate how long the non-military actions may take.

A second aspect is the idea for the international community (or specifically, the PS5+1 and even Russia were named) to help Iran in its civil nuclear plans. It seems like an idea that has potential to work– if the PS5+1 could assist Iran in designing, constructing, and fabricating the fuel for the light water reactors, and help with designing an indigenous power reactor and if Russia could train Iranians in fabricating fuel to eventually enable them to produce the fuel themselves. These proposed actions seem cooperative and likely to overcome the stalemate, since this idea seems to offer some concrete and specific “helpful” guidance towards the peaceful purposes claimed by Iran. While of course there is always the question of whether Iran’s intentions will stay peaceful or not, another question brought to mind is whether Russia would be cooperative. If Russia has thus far sold some material to Iran for questionable aims, the question of Russia’s willingness to cooperate and future possible actions is something that must be considered more thoroughly, in context of this idea. Otherwise, it seems that this idea has potential to help facilitate the cooperation from Iran needed to come to an ideal agreement. — M.

On the Iran Nuclear Crisis

Robert Einhorn’s report “Preventing a Nuclear Armed Iran” is particularly interesting not because its recommendations are that revolutionary, but because it suggests what the broad outlines are of the Obama administration’s negotiating strategy. Einhorn served until recently as the Department of State’s Special Advisor on Non-Proliferation and Arms Control, he maintains close ties with the negotiating team and his perspective is likely as close to official government policy as anything.

Einhorn acknowledges that the Iranians will insist on retaining uranium enrichment capacity and the ability to create nuclear arms if they deem it necessary. However, he believes US concerns can still be dealt with as long as the agreement makes any Iranian attempt at nuclear breakout a “detectable, lengthy and risky process that would not only fail but would inevitably result in Iran paying a very high price in terms of its national interests.”

Einhorn proposes several technical solutions to the problem, suggesting that the Fordow plant be turned into a research facility, that the Arak reactor’s ability to produce plutonium be greatly reduced, and that the Iranian program be subject to stringent monitoring by the IAEA.

Given that just last Saturday Iran’s Vice President announced plans to redesign the Arak plant to limit the plutonium it can make, it would seem that Einhorn’s proposal is already bearing fruit. By most media accounts, the negotiations between the West and Iran have proceeded very well to date. Iran has complied with the interim agreement, and is already ahead of schedule in diluting it’s enriched uranium as stipulated by the 6 month agreement. Representatives have even announced that they plan to Meet in New York in early May to start drafting the final text.

The greatest challenge to successful negotiations may come from hardliners within both countries. Republicans in the US and Netanyahu in Israel have been furious over the prospect of any deal that might permit Iran to continue enriching Uranium, and may attempt to scuttle it.

Rouhani’s administration recently admitted to reshuffling leadership positions in Iran’s atomic energy agency as a way of sidelining the hardliners, holdouts from the Ahmadinejad administration, who had opposed any deal. Ultimately the decision to proceed with the deal depends on Ayatollah Khamenei. Western media reports that he has been cautiously open to the possibility of a deal, but as long as his intentions remain uncertain so is the future of an accord between Iran and the US. — E. S.

Indirect Effects of Low Natural Gas Prices on Nuclear, Renewable and Coal-Fired Electricity Generation

Abundant natural gas resources and prevailing low prices are frequently credited with reducing coal-fired electricity generation and reducing carbon dioxide emissions from power plants. However, the same characteristics are putting similar stresses on future renewable and nuclear power generation, both low carbon sources of energy. The February 2013 Credit Suisse presentation cites low electricity prices as squeezing profit margins for nuclear plants. Credit Suisse concludes by suggesting that low prices could lead to a decrease in nuclear’s market share, which has traditionally stood at about 20% of US generation.

suisse2(c) Credit Suisse

Assuming that Credit Suisse is correct and nuclear begins to lose market share in the near term, the question is: “What fuel source will replace the lost nuclear capacity?” Three options exist, renewables, natural gas and coal. Two of those options, gas and coal, will cause a net increase in GHG emission from power plants when compared to existing nuclear reactors. Since nuclear is a base-load fuel, coal and gas are better suited than renewables to serve as direct replacements. Given EPA’s new and upcoming rules on coal plants, it is likely that much of the slack will be comprised of natural gas. However, increased demand and marginally higher gas prices may also cause old coal plants to stay online longer than they would otherwise.

In summation, natural gas has replaced some coal-fired generation and reduced emissions in the short-term; however, the indirect effects of low prices on nuclear and renewables could have a partially offsetting effect on emissions in future years. Given the Obama administration’s interest in reducing carbon pollution and moving away from coal, the nuclear industry should further investigate this effect to argue for license extensions, new plant approvals and increased R&D investment. — N. R.

On the Nuclear Middle Age Dilemma

Credit Suisse highlights a couple main themes in their presentation. First, the current nuclear fleet is operating under capacity. Second, costs for nuclear operation have been rising. And third, the current fleet of nuclear power plants is aging and replacement construction is not keeping pace.

The graphs I found the most interesting were on slides 12 and 17. Slide 12 shows cash margins for regulated utilities, and nearly a third of them operate at a loss for at least some power prices. The least cost effective, Monticello and San Onofre, operate at a loss for every power price, and this loss can be over $15/MWh at certain times. (In comparison, the most profitable can make up to $17/MWh and has a positive cash margin at any price, so there are still some profits to be made). With financial situations such as this, it is not surprising that plants are being powered off at times or permanently closed, and it seems unlikely that many new plants will come into operation. I was wondering what the trend is with newer plants. Do most face regulated markets, or are the new ones mostly merchant operations?

Slide 17 shows the age and capacity of the US nuclear plant fleet. The majority were built in the 1960s-80s, and only one was constructed after 1990 (note the graph ends in 2000). As the slide points out, most of the oldest plants are the smallest and standalone. I would be interested to hear more detail as to what the implications of this are, and how the economics of small standalone plants compares to that of larger and/or grouped plants. — A. D.

It’s Official: $3.5M for Nuclear Disarmament Research at Princeton

CVT We are happy to announce that we are part of the consortium that has been awarded the $25 million five-year grant to improve nuclear arms control verification technology (see NNSA press release from March 31, 2014). The consortium will be led by the University of Michigan, and also involves MIT, Columbia, North Carolina State, University of Hawaii, Pennsylvania State, Duke, University of Wisconsin, University of Florida, Oregon State, Yale, and the University of Illinois at Urbana Champaign.

Princeton leads a key research thrust of the consortium focused on the relevant policy dimensions: “Treaty Verification: Characterizing Existing Gaps and Emerging Challenges.” Together with PPPL, we will also be able to expand our technical work on zero-knowledge approach to nuclear warhead verification and will be developing a virtual environment to support development, testing, and demonstration of verification approaches for these treaties. We will report regularly at on the progress of this exciting opportunity. Watch this space.