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Open Source software enables innovative, community-based software development. ONIX brings this concept to the field of depletion calculations. It is an open-source depletion software to be used for nuclear reactor simulations, for fissile material production analysis as well as for nuclear arms control applications. ONIX provides a module to solve the depletion equation using a Chebyshev Rational Approximation Method. For the generation of one-group cross sections, it includes a coupling interface for the open-source neutron transport code, OpenMC, as well as a module to read pre-computed values in a stand-alone mode. ONIX has special features to optimize nuclear data libraries, to update isomeric branching ratio during burnup, and to support automation of simulations for nuclear archaeology. ONIX has been validated against results from numerical and experimental benchmarks, and its results agree with other methods within expected error ranges.

Burnup calculations are applied to determine the amount of krypton-85 that is produced during the irradiation of nuclear fuel. Since krypton-85 is most likely released into the atmosphere during reprocessing to separate plutonium, atmospheric transport modeling is used to calculate the worldwide distribution of krypton-85 concentrations stemming from emissions from declared reprocessing plants. The results are the basis for scenarios in which emissions from clandestine reprocessing facilities have to be detected against various background levels. It is concluded that today's background imposes heavily on the ability to detect small and medium plutonium separation rates; only high separation rates of 1 SQ per week and higher have a chance to be detected with feasible outlay. A fixed network of monitoring stations seems too costly; instead the high number of samples that are required rather calls for mobile sampling procedures, where air samples are collected at random locations over the world and are analyzed in regional laboratories for their krypton-85 concentration. Further, it is argued that krypton-85 emissions from declared reprocessing activities have to be significantly lowered to enable a worldwide verification of the absence of even smaller clandestine reprocessing. For each scenario the number of samples that have to be taken for probable detection is calculated.

The International Atomic Energy Agency (IAEA) defines uranium with a 235U isotope concentration of 20 percent as the threshold between low-enriched uranium (LEU) and highly enriched uranium (HEU), and as a significant waypoint on the path towards weapon-grade uranium (typically above 90 percent 235U enrichment). The distinction between LEU and HEU is widely used in shaping nonproliferation policy, and it has featured prominently in commentary over Iran's nuclear program and the series of Nuclear Security Summits that since 2010 have sought to minimize civilian stockpiles and use of HEU. Yet the origin of this threshold is obscure, dating back 6 decades. This research note traces the political origin and the technical basis for this limit.

The verification of arms-control and disarmament agreements requires states to provide declarations, including information on sensitive military sites and assets. There are important cases, however, where negotiations of these agreements are impeded because states are reluctant to provide any such data, because of concerns about prematurely handing over militarily significant information. To address this challenge, we present a cryptographic escrow that allows a state to make a complete declaration of sites and assets at the outset and commit to its content, but only reveal the sensitive information therein sequentially. Combined with an inspection regime, our escrow allows for step-by-step verification of the correctness and completeness of the initial declaration so that the information release and inspections keep pace with parallel diplomatic and political processes. We apply this approach to the possible denuclearization of North Korea. Such approach can be applied, however, to any agreement requiring the sharing of sensitive information., 14 pages, 4 figures

The process must reflect existing levels of trust at each stage

Nuclear weapons have re-emerged as one the main global security challenges of our time. Any further reductions in the nuclear arsenals will have to rely on robust verification mechanisms. This requires, in particular, trusted measurement systems to confirm the authenticity of nuclear warheads based on their radiation signatures. These signatures are considered extremely sensitive information, and inspection systems have to be designed to protect them. To accomplish this task, so-called information barriers" have been proposed. These devices process sensitive information acquired during an inspection, but only display results in a pass/fail manner. Traditional inspection systems rely on complex electronics both for data acquisition and processing. Several research efforts have produced prototype systems, but after almost thirty years of research and development, no viable and widely accepted system has emerged. This talk highlights recent efforts to overcome this impasse. A first approach is to avoid electronics in critical parts of the measurement process altogether and to rely instead on physical phenomena to detect radiation and to confirm a unique fingerprint of the inspected warhead using a zero-knowledge protocol. A second approach is based on a radiation detection system using vintage electronics built around a 6502 processor. Hardware designed in the distant past, at a time when its use for sensitive measurements was never envisioned, may drastically reduce concerns that another party implemented backdoors or hidden switches. Sensitive information is only stored on traditional punched cards. The talk concludes with a roadmap and highlights opportunities for researchers from the hardware security community to make critical contributions to nuclear arms control and global security in the years ahead.

In recent years, neutron detection with superheated emulsions has received renewed attention thanks to improved detector manufacturing and read-out techniques, and thanks to successful applications in warhead verification and special nuclear material (SNM) interdiction. Detectors are currently manufactured with methods allowing high uniformity of the drop sizes, which in turn allows the use of optical read-out techniques based on dynamic light scattering. Small detector cartridges arranged in 2D matrices are developed for the verification of a declared warhead without revealing its design. For this application, the enabling features of the emulsions are that bubbles formed at different times cannot be distinguished from each other, while the passive nature of the detectors avoids the susceptibility to electronic snooping and tampering. Large modules of emulsions are developed to detect the presence of shielded special nuclear materials hidden in cargo containers 'interrogated' with high energy X-rays. In this case, the enabling features of the emulsions are photon discrimination, a neutron detection threshold close to 3 MeV and a rate-insensitive read-out.

Measurement 114, 185 - 190 (2018). doi:10.1016/j.measurement.2017.09.014, Published by Elsevier Science, Amsterdam [u.a.]

Verification of current nuclear arms control treaties between United States and Russia relies primarily on the verification of delivery vehicles. Warheads are counted indirectly via the delivery vehicles that they are associated with. As states move to lower numbers of nuclear weapons in their arsenals, verification will likely pose complex challenges. Most importantly, future nuclear disarmament treaties may place limits on the total number of nuclear weapons in the arsenals. Their verification would require inspections of individual nuclear warheads without revealing secret information. Confirming the authenticity of nuclear warheads and perhaps also of warhead components is at the center of the verification challenge for future reductions in the nuclear arsenals. This paper provides an overview of the development of verification systems, and highlights the challenges and the opportunities for future research in this area.

The availability of fusion energy could prove valuable in meeting carbon mitigation targets over the course of the century. We use recent cost estimates for future fusion power plants in order to incorporate fusion into the Global Change Assessment Model (GCAM), a long-term energy and environment model used to study the interaction between technology, climate, and public policy. Results show that fusion's growth will depend on: the chosen carbon mitigation target (if any); the availability of competing carbon-neutral options for the provision of baseload electrical power, in particular nuclear fission as well as carbon capture and storage; the chosen discount rate; the initial year of availability; and the assumed costs of fusion electricity. We quantify the present value of the fusion option while varying the assumptions about these other parameters, and we find that it is, in general for our range of assumptions, significantly larger than the estimated cost of a comprehensive R&D plan to develop fusion energy. The results emphasize the wisdom in hedging against uncertainty in future technology availability by pursuing the development of multiple options that could feasibly play a major role in the latter half of the century.

This article examines possible modifications of Iran’s IR-40 (Arak) heavy-water reactor that would limit its plutonium production without compromising its usefulness for civilian purposes. The proposed modifications only involve the fuel composition, avoid changes to the fuel and core geometry, and therefore have the advantage of minimizing the overall complexity and cost of conversion as well as shortening the time period required to implement these modifications. The suggested changes would significantly reduce the reactor’s production of plutonium from 7–9 kilograms to less than 1 kilogram per year. The article also examines key safety parameters, medical isotope production rates, and uranium resource requirements for all modifications considered. The analysis is relevant beyond the case of Iran’s Arak reactor and may provide some future guidance for converting other heavy-water reactors that continue to operate today.

In circulating fuel reactors, such as the Molten Salt Reactor, the fuel circulates throughout the reactor instead of being immobile as in solid fuel reactors. The vast majority of nuclear simulation codes are primarily designed to simulate solid fuel reactors. Hence, many features unique to circulating fuel reactors, such as fuel injection and removal, cannot be properly modeled with these codes. The work presented here focuses on developing a numerical simulation package that can effectively and accurately model these reactors. This package consists of the coupling of the Monte Carlo particle transport code OpenMC with a modified version of ORIGEN-S, and uses a novel algorithm that calculates the optimal fuel injection and removal schemes for such reactors to achieve certain conditions such as a stable reactivity. We demonstrate our code’s accuracy by benchmarking the coupling module with the MCODE coupling code, and by simulating the operation of the ORNL Denatured Molten Salt Reactor using the coupling and fuel injection modules. The resulting fuel injection scheme is in agreement with the original study of that reactor while offering a much finer resolution for the injection scheme over time. This work is part of a broader project to develop an open-source neutronics code for circulating fuel reactors that will couple OpenMC with an in-house open-source depletion module.

Verifying limits on the stockpiles of nuclear weapons may require the ability for international in-spectors to account for individual warheads, even when non-deployed, and to confirm the authenticity of nuclear warheads prior to dismantlement. These are fundamentally new challenges for nuclear verification, and they have been known for some time; unfortunately, due to a lack of sense of urgency, research in this area has not made substantial progress over the past 20 years. This chapter explores the central outstanding issues and offers a number of possible paths forward. In the case of confirming numerical limits, these in-clude innovative tagging techniques and approaches solely based on declarations using modern crypto-graphic escrow schemes; with regard to warhead confirmation, there has recently been increasing interest in developing fundamentally new measurement approaches where, in one form or another, sensitive infor-mation is not acquired in the first place. Overall, new international R&D efforts could more usefully focus on non-intrusive technologies and approaches, which may show more promise for early demonstration and adoption. In the meantime, while warhead dismantlements remain unverified, nuclear weapon states ought to begin to document warhead assembly, refurbishment, and dismantlement activities and movements of warheads and warhead components through the weapons complex in ways that international inspectors will find credible at a later time. Again, such a process could be enabled by modern cryptographic techniques such as blockchaining. Finally, and perhaps most importantly, it is important to recognize that the main reason for the complexity of technologies and approaches needed for nuclear disarmament verification is the requirement to protect information that nuclear weapon states consider sensitive. Ultimately, if information security concerns cannot be resolved to the satisfaction of all stakeholders, an alternative would be to “reveal the secret” and to make available select warhead design information.

The verification of nuclear warheads for arms control involves a paradox: international inspectors will have to gain high confidence in the authenticity of submitted items while learning nothing about them. Proposed inspection systems featuring 'information barriers', designed to hide measurements stored in electronic systems, are at risk of tampering and snooping. Here we show the viability of a fundamentally new approach to nuclear warhead verification that incorporates a zero-knowledge protocol, which is designed in such a way that sensitive information is never measured and so does not need to be hidden. We interrogate submitted items with energetic neutrons, making, in effect, differential measurements of both neutron transmission and emission. Calculations for scenarios in which material is diverted from a test object show that a high degree of discrimination can be achieved while revealing zero information. Our ideas for a physical zero-knowledge system could have applications beyond the context of nuclear disarmament. The proposed technique suggests a way to perform comparisons or computations on personal or confidential data without measuring the data in the first place.

Nuclear weapon states historically have attached great secrecy to their nuclear weapon and fissile material production programs and stockpiles, despite warnings that this would fuel fears, handicap informed debate and decision making, and drive arms races. As evidenced by the “Action Plan on Nuclear Disarmament” agreed upon at the 2010 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) Review Conference, however, the international community now sees greater transparency about nuclear weapon and fissile material stocks as necessary for enabling and monitoring progress toward nuclear disarmament. To support this effort, the International Panel on Fissile Materials has proposed a step-by-step program for weapon states to declare their inventories, production histories, and disposition of nuclear warheads and fissile materials, and to set up joint projects to develop methods for verifying these declarations. This openness initiative is described here, and could be adopted at the 2015 NPT Review Conferen...

Gaseous diffusion was historically the most widely used technology for military production of highly enriched uranium. Since June 2013, all gaseous diffusion enrichment plants worldwide are permanently shut down. The experience with decommissioning some of these plants has shown that they contain large amounts of uranium particles deposited in the cascade equipment. This article evaluates the potential of using uranium particle deposition to understand and reconstruct the operating histories of gaseous diffusion enrichment plants. First, a squared-off cascade enrichment model is derived to estimate the enrichment capacity of a reference plant. Then, using a cross-flow filtration model, the mass of solid uranium particles deposited over time in the tubular separation membranes of the stage diffusers is calculated. Finally, potential techniques to characterize these uranium deposits and help reconstruct the operating history of the plant are assessed.

In April 2015, Iran and the E3+3 nations (France, Germany, and the United Kingdom, plus China, Russia, and the United States) negotiated a framework for a “comprehensive solution that will ensure the exclusively peaceful nature of the Iranian nuclear program” ( 1 , 2 ). 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? 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.

Small modular reactor designs with power levels of less than 300 MWe are being developed in several countries. While there are several potential advantages with these reactors, they are also confronted with multiple challenges. Important among these challenges is to have these new reactor designs licensed by national regulatory bodies. Because of the many novel features incorporated in different SMR (small modular reactor) designs, careful and thorough licensing procedures are critical to maintaining safety of the nuclear fleet. This paper examines how different countries have engaged in the process of licensing new reactor designs, and demonstrates both similarities and differences between countries. In many cases, designers have emphasized the safer design and deployment features of SMRs and attempted to use those features as reasons to get existing licensing requirements diluted. This raises the concern that the promised safety enhancements in SMR designs could be offset by a simultaneous relaxation of licensing requirements.

Small modular reactors (SMRs) with power levels much smaller than the currently standard 1000- to 1600-MW(electric) reactor designs have been proposed as a potential game changer for the future of ...

The Transport Layer Security (TLS) protocol is still the de-facto standard for secure network connections over an insecure medium like the Internet. But its flexibility concerning the algorithms used for securing a channel between two parties can also be a weakness, due to the possible agreement on insecure ciphers. State of the art cipher suites are not supported by all websites. We relate on an existing white paper (Applied Crypto Hardening) giving recommendations on how to securely configure SSL/TLS connections with regard to the practical feasibility of these recommendations. In addition, we propose an additional configuration set with the aim of increasing compatibility as well as security. We also developed a small Cipher Negotiation Crawler (CiNeg) to test TLS-handshakes using given cipher configurations with Alexa’s top websites and show its practical usability. In this work we examine the trend regarding supported cipher suites on webservers over time. To analyze this, we performed the scans twice with a one year gap. We compared the outcome of the two scans to see if we can determine a trend to better security as time goes by. And indeed, we found explicit enhancements in our reevaluations.

Shortly after the accident at the Fukushima Daiichi Nuclear Power Station, Germany’s government started preparing legislation that would close the country’s last nuclear power plant by 2022. But th...

Converting research reactors from highly enriched uranium (HEU) fuel to more proliferation-resistant low-enriched fuel is critical for achieving the objective of ending the use of directly weapon-usable materials in the civilian nuclear fuel cycle. The most challenging type of reactors to convert are high-flux research reactors, which, along with upcoming strong spallation sources, are the most important neutron sources for sophisticated neutron scattering experiments. Advanced Monte-Carlo computer codes are now available that make it possible to track neutrons from the neutron source, through neutron guides, to the detector of a neutronic experimental setup, including realistic samples. These “virtual experiments” allow optimizing the performance of complete beamlines, where in many cases a large unused potential exists for increasing the neutron flux at the sample or detector position. The Monte-Carlo codes VITESS and McStas are used to compare results for typical neutron scattering setups using typical...

Unprecedented interest in seeking progress toward nuclear disarmament exists today; even some nuclear weapon states are looking for new ways to strengthen this process. National declarations of fissile material holdings—highly enriched uranium and plutonium—could play an important role in supporting this effort, facilitating not only transparency but also the irreversibility of the process. This article discusses what kind of content such declarations could have in order to be meaningful and effective, the sequence of data on fissile material holdings that states might release, and some of the challenges to be expected in reconstructing historic fissile material production; it also summarizes current attitudes of weapon states toward making such declarations. Initial declarations can be valuable as confidence-building measures, but better and more background data are necessary if declarations are to serve as the groundwork for deeper cuts in the nuclear arsenals. A robust verification approach would ultim...

There is growing interest in a set of methods and tools that can be used to characterize past fissile material production activities, using measurements and sampling at production and storage sites. This field has been dubbed “nuclear archaeology.” The best-established example of nuclear archaeology relies on measurements of the isotope ratios of selected elements in the graphite of graphite-moderated plutonium production reactors. This Graphite Isotope-Ratio Method (GIRM) determines the cumulative neutron fluence through the graphite and thereby estimates the cumulative plutonium production in the reactor. The great limitation of this particular method is that it can only be applied to graphite-moderated reactors, which represent only one class of reactors that have been used for unsafeguarded plutonium production. In this article, we propose to extend this method to non-graphite moderated reactors by analyzing the evolution of relevant isotope ratios in the support structures and other core components o...

Proliferation concerns have generally been associated with the acquisition of the fissile material needed for nuclear weapons; however, the spread of the knowledge needed to build very light and po...

One particularly important lesson for responsible energy policy can be learned from Germany: one may agree or disagree with its decision to respond so radically to the Fukushima accidents, but the experience has shown that it is critically important to have alternative energy strategies available in case a technology has to be taken off the table.

We report neutronics calculations for the most important natural uranium-fueled reactor types historically used for weapons plutonium production. These include an early design of the Hanford-type graphite-moderated and light-water-cooled reactor used in the United States; the Calder Hall-type graphite-moderated and gas-cooled reactor used in the United Kingdom; and the NRX-type heavy-water-moderated and light-water-cooled reactor, originally developed in Canada for civilian purposes but later used in India and Pakistan for military plutonium production. We show that while it is possible in principle to identify with a high level of confidence weapon-grade plutonium compositions produced in other types of reactors, e.g., light-water-cooled or fast neutron reactors, it is difficult to distinguish among plutonium compositions generated in dedicated production reactors fueled with natural uranium. This suggests that efforts to determine the origin of weapon-grade plutonium for a nuclear forensic analysis could well remain inconclusive without access to databases based on actual samples of the nuclear material.

One challenge to a potential verification regime for a Fissile Material Cutoff Treaty (FMCT) would be to assure that enrichment plants are not producing highly enriched uranium (HEU) for weapons purposes. Namely in some older enrichment plants, operated in nuclear weapon states, environmental sampling techniques might detect particles from historic HEU production. Determination of the age of these particles would be the most direct confirmation of treaty-compliance. While methods are available to determine the age of nuclear materials based on the concentrations of decay products, micron-sized uranium particles are particularly difficult to analyze. We will review the sensitivity requirements for age determination of HEU particles in an FMCT, and assess the potential of advanced measurement techniques available for this application.

Civilian and military stockpiles of materials that can be used to make nuclear weapons continue to pose global risks.

This article presents estimates of global and national stockpiles of highly enriched uranium and separated plutonium based on the 2008 Global Fissile Material Report by the International Panel on Fissile Materials. 1 The global stockpile of highly enriched uranium (HEU) is estimated to be 1670 ± 300 tons. It is declining as Russia and the United States blend down about 40 tons per year of HEU for use in light-water power-reactor fuel. This rate of blend-down is far higher than the estimated rate of production of HEU, currently believed to be limited to production by Pakistan for weapons and by India for naval fuel. The global stockpile of separated plutonium, all of which can be used for weapons, is about 500 tons. About half of this stockpile is civilian and is currently growing at less than 5 tons a year. This rate will increase significantly once Japan's Rokkasho reprocessing plant begins commercial operation. Only India and Pakistan and perhaps Israel are believed to be producing plutonium for weapons...

This article presents an analytical model, originally developed in the 1980s, for the gas centrifuge and uses this methodology to determine the main design and operational characteristics of several hypothetical centrifuge designs. A series of simulations for a typical first-generation machine is used to assess the relevance of important breakout scenarios, including batch recycling and cascade interconnection, using either natural uranium or preenriched material as feedstock.

Uranium enrichment by centrifugation is the basis for the quick and efficient production of nuclear fuel-or nuclear weapons.

This Resource Letter provides a guide to the literature on nuclear arms control for the nonspecialist. Journal articles and books are cited for the following topics: nuclear weapons, fissile materials, nonproliferation, missiles and missile defenses, verification, disarmament, and the role of scientists in arms control.

India is building a 500 MWe Prototype Fast Breeder Reactor, which is scheduled to be operational by 2010. India has refused to accept international safeguards on this facility, raising concerns that the plutonium produced in its uranium blankets might be used to make nuclear weapons. Based on neutronics calculations for a detailed three-dimensional model of the reactor, we estimate that up to 140 kg of weapon-grade plutonium could be produced with this facility each year. This article shows how India's large stockpile of separated reactor-grade plutonium from its unsafeguarded spent heavy-water reactor fuel could serve as makeup fuel to allow such diversion of the weapon-grade plutonium from the blankets of the fast breeder reactor. We describe and assess the most plausible refueling strategies for producing weapon-grade plutonium in this way.

This article reviews the rationale of selecting an enrichment of just less than 20% (low-enriched uranium) as the preferred enrichment level for research reactor fuel in order to minimize overall proliferation risks. The net strategic value of the nuclear material associated with reactor operation is evaluated for a variety of enrichment levels, ranging from slightly enriched to weapon-grade fuel. To quantify the proliferation potential, both the demand of fresh uranium fuel as well as the plutonium buildup in the irradiated fuel are estimated via cell burnup calculations. The analysis confirms the usefulness of the current enrichment limit and challenges a recent trend to reconsider fuel enrichment levels between 20% and 50% for new research reactor projects.

Civilian research reactors contain highly enriched uranium (HEU) that could be used by the terrorists to build nuclear bombs. HEU is a uranium in which uranium 235, the isotope capable of sustaining a nuclear chain reaction, has been concentrated to levels of 20 percent or more by weight. People have raised credible concerns that suicidal malefactors could penetrate an HEU storage facility, construct a so-called improvised nuclear device and detonate it before security guards could respond. The US and its allies have established programs to bolster security measures, convert reactors to use low-enriched uranium and retrieve HEU from research- reactor sites around the world. Language: en

The September 11 terrorist attacks demonstrated that the technical competence, available resources, level of preparation and suicidal determination of contemporary terrorist groups like al Qaeda have greatly increased over the last decade. This article will consider the likelihood that sophisticated terrorist groups could successfully launch sabotage attacks against nuclear research reactors and cause radiological releases that threaten nearby populated neighborhoods. While the theft by terrorists of highly enriched uranium (HEU) from research reactors to make relatively simple gun-type nuclear explosives has been a concern for some time, the sabotage threat to research reactors—a threat which is independent of fuel enrichment—has not been widely addressed. Nuclear regulators should reassess the level of physical protection that research reactor operators provide in light of the increased terrorist threat.

1. Prostaglandins play a major role in maintaining ductal patency in utero. Ductal tone is regulated by both locally released and circulating vasodilatory prostaglandins. In infants with ductus arteriosus-dependent congenital heart disease, ductal patency is maintained by intravenous administration of prostaglandin (PG) E(1). Little information is available regarding the expression of prostaglandin receptors in man. 2. By means of RT-PCR and immunohistochemistry we studied the expression of the PGI(2) receptor (IP), the four different PGE(2) receptors (EP1, EP2, EP3 and EP4), and the receptors for thromboxane (Tx) A(2) (TP), PGD(2) (DP) and PGF(2alpha) (FP) in the ductus arteriosus of three newborn infants with ductus arteriosus-dependent congenital heart disease and intravenous infusion of PGE(1) and of one 8 month old child with a patent ductus arteriosus. 3. The EP3, EP4, FP, IP and TP receptor were markedly expressed at the mRNA and protein level, whereas the EP2 receptor was weakly expressed and the EP1 receptor was detected in two out of four tissue specimens only. The DP receptor was not detected in any of the samples. The most pronounced expression, which was located in the media of the ductus arteriosus, was observed for the EP4 and TP receptors followed by IP and FP receptor protein. 4. These data indicate that ductal patency during the infusion of PGE(1) in infants with ductus arteriosus-dependent congenital heart disease might be mediated by the EP4 and IP receptor. The data further suggest that a heterogeneous population of prostanoid receptors may contribute to the regulation of ductus arteriosus tone in humans.

The use of highly enriched uranium (HEU) as fuel in research reactors runs contrary to the concept of proliferation-resistant nuclear technologies. Consequently, for more than two decades, international activities have been undertaken to terminate the use of HEU in research reactors by supporting the conversion of these facilities to low-enriched uranium (LEU). Achievements, setbacks and perspectives of these efforts are discussed in this article. The German research reactor FRM-II, which will presumably begin operation in 2002, would be the world's first HEU-fueled reactor in more than 10 years. Among proponents and critics of HEU use in this reactor there is disagreement on the scientific impact of FRM-II conversion, which could be based on designs proposed by Argonne National Laboratory (ANL). In order to support the decision-making process, independent computer simulations have been performed that provide detailed information on the scientific usability of the converted reactor. The most important res...

Small Modular Reactors (SMRs) with power levels of below 300 MW(e) appear to have several favorable characteristics and their deployment might help bring about a big change in how nuclear power fares in the future. Numerous SMR designs with distinct characteristics are under development in several countries. To capture the impacts of these different designs, we have developed notional models for two leading SMR types and performed neutronics calculations on these to estimate uranium resource requirements. These are then used to explore the resulting waste generation and potential proliferation risks.Copyright © 2013 by ASME

Nuclear proliferation risks from magnetic fusion energy associated with access to fissile materials can be divided into three main categories: 1) clandestine production of fissile material in an undeclared facility, 2) covert production and diversion of such material in a declared and safeguarded facility, and 3) use of a declared facility in a breakout scenario, in which a state openly produces fissile material in violation of international agreements. The degree of risk in each of these categories is assessed, taking into account both state and non-state actors, and it is found that safeguards are required for fusion energy to be highly attractive from a non-proliferation standpoint. Specific safeguard requirements and R&D needs are outlined for each category of risk, and the technical capability of the ITER experiment, under construction, to contribute to this R&D is noted. A preliminary analysis indicates a potential legal pathway for fusion power systems to be brought under the Treaty for the Non-Proliferation of Nuclear Weapons. "Vertical" proliferation risks associated with tritium and with the knowledge that can be gained from inertial fusion energy R&D are outlined.