Differences between neutron damage in inertial and magnetic confinement fusion materials test facilities

This book is a collection of papers, written by specialists in the field, on advanced topics of nuclear fusion diagnostics. The 78 contributions were originally presented at the International Conference on Advanced Diagnostics for Magnetic and Inertial Fusion held at Villa Monastero, Italy in September 2001. Both magnetically confined and inertial fusion programmes are quite extensively covered, with more emphasis given to the former scheme. In the case of magnetic confinement, since the present international programme is strongly focused on next-step devices, particular attention is devoted to techniques and technologies viable in an environment with strong neutron fluxes. Indeed, in the first section, the various methods are considered in the perspective of performing the measurements of the relevant parameters in conditions approaching a burning plasma, mainly in the Tokamak configuration. The most demanding requirements, like the implications of the use of tritium and radiation resistance, are reviewed and the most challenging open issues, which require further research and development, are also clearly mentioned.The following three sections are devoted to some of the most recent developments in plasma diagnostics, which are grouped according to the following classification: `Neutron and particle diagnostics', `Optical and x-ray diagnostics' and `Interferometry, Polarimetry and Thomson Scattering'. In these chapters, several of the most recent results are given, covering measurements taken on the most advanced experiments around the world. Here the developments described deal more with the requirements imposed by the physical issues to be studied. They are therefore more focused on the approaches adopted to increase the spatial and time resolution of the diagnostics, on some methods to improve the characterisation of the turbulence and on fast particles. Good coverage is given to neutron diagnostics, which are assuming increasing relevance as the plasma parameters approach ignition. Spectroscopic systems and their recent developments are well represented, whereas edge diagnostics are somewhat thin on the ground. A dedicated section is devoted to the latest tests on radiation effects and technological issues. The problems of damage to optical components and the difficulties presented by the determination of the tritium inventory are described.In the last part, the new diagnostic systems of the most recent experiments (under construction or recently operated) are reported. Various aspects of some diagnostics not included in the three previous sections are also covered, with particular emphasis on microwaves and infrared diagnostics.The book is well suited for specialists and, more generally, for people involved in nuclear fusion, who need information about the most recent developments in the field of plasma diagnostics. The papers cover many aspects of the challenges and possible solutions for performing measurements in fusion machines approaching reactor conditions. On the other hand, the contributions are in general quite advanced and would be challenging for people without a significant background in plasma diagnostics and nuclear fusion. The quality of the paper is more than satisfactory both from the point of view of clarity and of graphics. Moreover, at the beginning of the book, several papers make a considerable effort to put diagnostic issues in the wider context of present day nuclear fusion research. For those topics, which are too involved to be completely described in a conference contribution, in general adequate references are provided for deeper investigation.A MurariApproximately one third of the papers included in this volume deal with diagnostics related to inertial confinement fusion plasmas (i.e., laser-produced plasmas and pulsed-power). These papers discuss recent developments in charged particle diagnostics, neutron diagnostics, optical and x-ray measurements along with laser and particle probing diagnostics. The resulting collection of papers is comprehensive and wide-ranging and all of the major laboratories in Europe, the US, and Japan are represented. There is important discussion on the development of diagnostics for the National Ignition Facility, LMJ, and future ultra-high intensity laser experiments as well as papers on wire array z-pinch experiments. It is especially useful to have the contributions from inertial confinement fusion experiments intermingled with those from magnetic confinement fusion. The separation between these two approaches to fusion is often unfortunately large, so one of the pleasing things about this book is that it is very easy for readers familiar with experimental research in one area to compare `state of the art' plasma diagnostics in the other area. Hopefully this will facilitate the development of new ideas in both areas. This book is a conference proceedings and as such, almost all of the papers included are quite brief and are highly technical. Consequently, the book is not particularly pedagogical and would be most useful to researchers already working in this area of physics. For these readers, however, Advanced Diagnostics for Magnetic and Inertial Confinement Fusion is an excellent overview of the present status of fusion plasma diagnostics.K Krushelnick

Inertial Confinement Fusion and Magnetic Confinement Fusion (ICF and MCF) follow different paths toward goals that are largely common. In this paper, the claim is made that progress can be accelerated by learning from each other across the two fields. Examples of successful cross-community knowledge transfer are presented that highlight the gains from working together, specifically in the areas of high-resolution x-ray imaging spectroscopy and neutron spectrometry. Opportunities for near- and mid-term collaboration are identified, including in chemical vapor deposition diamond detector technology, using gamma rays to monitor fusion gain, handling neutron-induced backgrounds, developing radiation hard technology, and collecting fundamental supporting data needed for diagnostic analysis. Fusion research is rapidly moving into the igniting and burning regimes, posing new opportunities and challenges for ICF and MCF diagnostics. This includes new physics to probe, such as alpha heating; increasingly harsher environmental conditions; and (in the slightly longer term) the need for new plant monitoring diagnostics. Substantial overlap is expected in all of these emerging areas, where joint development across the two subfields as well as between public and private researchers can be expected to speed up advancement for all.

The Workshop: Facts and Outcome

As far as is known, nuclear fusion is the primary source of energy in the universe. It occurs when the nuclei of lighter elements, such as hydrogen, are fused together at extremely high temperatures and pressure to form heavier elements, such as helium. Whereas practical methods for harnessing fusion reactions and realizing the potential of this energy source have been sought since the 1950s, achieving the benefits of power from fusion has proved to be a difficult, long‐term challenge. Fusion is widely held to be the ultimate resource for the world's long‐term energy needs. The fuel reserves for fusion are virtually limitless and available to all countries. Fusion fuels can be extracted from water. Fusion promises to be an energy source which is potentially safe and environmentally benign. Radiological and proliferation hazards are much smaller than for fission power plants. The atmospheric impact is negligible compared to fossil fuels, and adverse impacts on the Earth's ecological and geophysical processes are smaller than for large‐scale renewable energy sources. The economics and costs of fusion power plants are still being studied, but appear comparable to those for other medium‐ and long‐term energy sources. The promise of affordable essentially unlimited supplies of clean, safe energy, free of political boundaries, has motivated a world‐wide research effort to develop this energy resource. The reactions of deuterium, tritium, and helium‐3, 3 He, having nuclear charges of 1, 1, and 2, respectively, are the easiest to initiate. These have the highest fusion reaction probabilities and the lowest reactant energies. Two diverse technical approaches to fusion power, magnetic confinement fusion, also known as magnetic fusion energy (MFE) and inertial confinement fusion, also known as inertial fusion energy (IFE) are being pursued worldwide. These form the basis of a large number of fusion research programs. Fusion energy research is also the primary avenue for the development of plasma physics as a scientific discipline.

Geometrical and spectral differences between inertial confinement fusion (ICF) and magnetic confinement fusion (MCF) facilities lead to significant variation of up to ∼ 60% in peak values and profiles of the time averaged blanket nuclear parameters for the same first wall exposure. Simple scaling of radiation effects with neutron wall loading is inappropriate. These effects together with the temporal effects, that result in ∼ 5 to 8 orders of magnitude higher instantaneous reaction rates in the pulsed ICF reactors, lead to significantly different blanket performances in the ICF and MCF reactor environments.

Damage parameters of structural materials in fusion environment compared to fission reactor irradiation

This article explores controlled fusion as a promising avenue for sustainable energy production. It delves into two leading approaches -Magnetic Confinement Fusion (MCF) and laser-driven Inertial Confinement Fusion (ICF)— highlighting their principles and challenges. These artificial methods are compared with natural stellar fusion to underscore the distinct physical and technical challenges of achieving controlled fusion on Earth. While significant progress has been made, challenges in energy efficiency, plasma stability, and scalability remain, guiding the trajectory of future research.

Vladislav Nikolaevich Mokhov, an outstanding scientist, Doctor of Science in Physics and Mathematics, professor, died on December 27, 2011 after long time of severe disease. Before this illness he was Deputy Scientific Leader of the All-Russian Research Institute of Experimental Physics (VNIIEF). V.N. Mokhov was born on April 12, 1931 in the town of Atkarsk, Saratov region, Russia. In 1955, after graduation from the Moscow Engineering Physics Institute, he in a group of the most brilliant and talented young theoreticians was selected by Academicians Ya.B. Zel'dovich and A.D. Sakharov for work on the nuclear weapons program at VNIIEF. In 1963, he was awarded the Lenin Prize for the development of new principles and new approaches to nuclear and thermonuclear weapons design and controlled fusion; in 1964, he received the degree of Candidate of Science, and four years later, the degree of Doctor of Science. V.N. Mokhov was always inspired by challenging projects that required teamwork of theoreticians, designers, and experimentalists. His major scientific and practical results include: Development of the theory of turbulent mixing in layered structures at intense compression. The results obtained are relevant for studying the processes occurring in inertial confinement fusion (ICF) targets.; Ignition of thermonuclear fuel by its heating with fast compression, which was and continues to be very important for the development of a number of special-purpose nuclear charges and fusion targets.; Development of “clean” nuclear charges for peaceful applications (jointly with the team of colleagues).; The new approach to the controlled thermonuclear fusion - the MAGO (MAGnitnoye Obzhatiye, or magnetic compression) - was proposed and developed jointly with his team. V.N. Mokhov considered MAGO to be a system that now made it possible to achieve the scientific breakeven point for fusion without the large initial capital investment that is required by the two more conventional approaches, magnetic confinement fusion and ICF.; Investigation of physical properties of materials at high energy densities provided by explosive magnetic flux compression generators (EMG). Jointly with his team, V.N. Mokhov proposed and developed methods of this investigation, obtained novel results on dynamic strength of a number of materials (aluminum, copper, polyethylene). In 1998, he and some of his colleagues were awarded the RF Government Prize for the development of EMGs and their application for scientific investigations. V.N. Mokhov was one of the pioneers of scientific cooperation between US and Russian nuclear laboratories. This mutually beneficial cooperation between the two countries produced extremely interesting scientific results obtained during joint research activities, including more than 20 series of experiments, and published in more than 400 papers and presentations. Equally important is that he was a true friend of many US scientists, and this friendship between people from different countries and trust in each other made the world better. V.N. Mokhov was a very interesting person having his original opinion on nearly any issue - whether related to science, history or politics. Many of his ideas on these issues were reflected in his papers available to a broad public and in his book “Nuclear Weapons and Safe Stable World. These ideas were extremely up-to-date in due time, and they continue to be relevant these days.

The paper reviews the present status of the available key technologies for implosion experiments as regards the energy driver, pellet fabrication, diagnostics of dense and hot plasmas, and numerical simulations. It is shown that the development of the necessary conditions is well advanced so that it is now possible to proceed to the next step in the achievement of ignition and break-even. Various design studies for inertial confinement fusion reactors are also reviewed; from these studies it has become clear that inertial confinement fusion and magnetic confinement fusion are technologically complementary systems for future fusion reactors.

"STARPOWER: The U.S. and International Quest for Fusion Energy." Fusion Technology, 13(4), pp. 662–663 Additional informationNotes on contributorsStephen O. DeanStephen O. Dean, president of Fusion Power Associates, has been an active fusion researcher and manager for 25 years. As president of Fusion Power Associates, which he cofounded in 1979, he actively explains and promotes fusion to a broad audience that includes congressional staff and science reporters. He sponsors symposia that bring together senior managers and researchers in both magnetic and inertial confinement fusion. As director of the Magnetic Confinement Systems Division at the U.S. Atomic Energy Commission/Energy Research and Development Administration/U.S. Department of Energy in the 1970s, he directed the growth of the major programs in tokamaks and magnetic mirrors at U.S. laboratories. In the late 1960s and early 1970s, he initiated and conducted experimental research in laser fusion at the Naval Research Laboratory.

The nuclear research and development community has a history of using both integral and differential experiments to support accurate lattice-reactor, nuclear reactor criticality and shielding simulations, as well as verification and validation efforts of cross sections and emitted particle spectra. An important aspect to this type of analysis is the proper consideration of the contribution of the neutron spectrum in its entirety, with correct propagation of uncertainties and standard deviations derived from Monte Carlo simulations, to the local and total uncertainty in the simulated reactions rates (RRs), which usually only apply to one application at a time. This paper identifies deficiencies in the traditional treatment, and discusses correct handling of the RR uncertainty quantification and propagation, including details of the cross section components in the RR uncertainty estimates, which are verified for relevant applications. The methodology that rigorously captures the spectral shift and cross section contributions to the uncertainty in the RR are discussed with quantified examples that demonstrate the importance of the proper treatment of the spectrum profile and cross section contributions to the uncertainty in the RR and subsequent response functions. The recently developed inventory code FISPACT-II, when connected to the processed nuclear data libraries TENDL-2015, ENDF/B-VII.1, JENDL-4.0u or JEFF-3.2, forms an enhanced multi-physics platform providing a wide variety of advanced simulation methods for modelling activation, transmutation, burnup protocols and simulating radiation damage sources terms. The system has extended cutting-edge nuclear data forms, uncertainty quantification and propagation methods, which have been the subject of recent integral and differential, fission, fusion and accelerators validation efforts. The simulation system is used to accurately and predictively probe, understand and underpin a modern and sustainable understanding of the nuclear physics that is so important for many areas of science and technology; advanced fission and fuel systems, magnetic and inertial confinement fusion, high energy, accelerator physics, medical application, isotope production, earth exploration, astrophysics and homeland security.

Atomic data for highly charged ions: Applications to X-ray laser design and thermonuclear fusion

The demonstration of inertial fusion energy (IFE) will require the construction of a sequence of physics and engineering test facilities. A key facility in the development path is the Integrated Test Facility (ITF). The ITF will be the first facility to integrate all the major subsystems required for an inertial fusion power plant including the driver, target production and injection systems, and reactor systems (chamber, blanket, heat removal, tritium recovery, etc.); it will demonstrate the technical feasibility of IFE. In this paper we describe the features of a heavy ion fusion ITF that takes advantage of the unique characteristics of inertial fusion in order to reduce development time and costs. Because fusion capsule ignition and burn physics are independent of the reaction chamber size, feasibility tests of various chamber concepts can be done at much smaller sizes (about 1-2 m first wall radius) and much lower powers (tens of MWs) than magnetic fusion development facilities such as ITER.

Three models for nonlocal electron thermal transport are here compared against Vlasov-Fokker-Planck (VFP) codes to assess their accuracy in situations relevant to both inertial fusion hohlraums and tokamak scrape-off layers. The models tested are (i) a moment-based approach using an eigenvector integral closure (EIC) originally developed by Ji, Held, and Sovinec [Phys. Plasmas 16, 022312 (2009)]; (ii) the non-Fourier Landau-fluid (NFLF) model of Dimits, Joseph, and Umansky [Phys. Plasmas 21, 055907 (2014)]; and (iii) Schurtz, Nicolaï, and Busquet’s [Phys. Plasmas 7, 4238 (2000)] multigroup diffusion model (SNB). We find that while the EIC and NFLF models accurately predict the damping rate of a small-amplitude temperature perturbation (within 10% at moderate collisionalities), they overestimate the peak heat flow by as much as 35% and do not predict preheat in the more relevant case where there is a large temperature difference. The SNB model, however, agrees better with VFP results for the latter problem if care is taken with the definition of the mean free path. Additionally, we present for the first time a comparison of the SNB model against a VFP code for a hohlraum-relevant problem with inhomogeneous ionisation and show that the model overestimates the heat flow in the helium gas-fill by a factor of ∼2 despite predicting the peak heat flux to within 16%.

Strategy toward inertial fusion energy