Countries other than the United States and consortia of countries are seeking to attain fusion energy. These facilities and programs are briefly described in this appendix.
EUROPEAN UNION—HIGH POWER LASER ENERGY RESEARCH (HiPER)
The High Power Laser Energy Research (HiPER) project is an international collaborative research activity to design a high-power laser fusion facility capable of “significant energy production.”1 It is funded by 10 funding agency partners in the European Union (from the United Kingdom, France, the Czech Republic, Greece, Spain, and Italy) and has 17 institutional partners. A coordinated science and technology effort to achieve HiPER exists between major laser laboratories such as Laser MégaJoule (LMJ), the PETawatt Aquitaine Laser (PETAL), Orion, the Extreme Light Infrastructure (ELI), and the Prague Asterix Laser System (PALS), with each lab investigating discrete elements of interest.
The driver for HiPER consists of diode pumped solid-state lasers (DPSSLs). Their preliminary design has not yet specified a particular DPSSL material, but a few are under consideration at this time, such as cryocooled Yb:CaF2, Yb:YAG, and ceramic Yb:YAG. These materials can be made in large sizes, easily scaled, and have a wide industrial base on which to draw on from the EU countries.
Although other methods are under consideration, HiPER appears to favor the direct drive, shock ignition method. The project is collaborating with universities on the development of technologies for fast ignition. HiPER appears to have no intention of pursuing indirect drive ignition, possibly, at least in part, because French law forbids use of military program data for civilian use. The U.K.’s Atomic Weapons Establishment has been working with the United States on indirect drive at the National Ignition Facility (NIF).
The preliminary design for the ignition target for HiPER uses an aluminum shell containing deuterium-tritium (DT) ice and vapor; a gain greater than 100 is desired for commercial inertial fusion energy (IFE) purposes. Mass production, cryolayering, and chamber injection of these targets are currently under study by Micronanics, General Atomics, and laboratories in the Czech Republic. Much of the design of European approaches to IFE is being done using DUED, a code developed in Italy, and MULTI, a code developed in Spain.
A two-stage development approach to the HiPER chamber is under consideration. The first stage would be a technology integration demonstration, while the next stage would be an IFE reactor. A “consumable” first wall concept is being studied wherein the damaging effects of debris and reaction products on the first wall are mitigated. One consumable wall concept involves gas-filled removable tiles as a modular solution to this problem. Partnerships with the magnetic fusion energy (MFE) community could be of interest for solving these challenges, which are not unique to IFE.
A 3- to 5-kJ laser unit representative of a larger modular scheme for HiPER is currently under development by four European Union teams. The goal of this research thrust is to have a 10 percent efficient laser capable of reaching 1 MJ of energy at 10 Hz.
The timeline for the entire HiPER project begins with a technological development and risk reduction phase from the present to approximately 2020; a design, build, and test phase from approximately 2017 to 2029; and, finally, a reactor design phase from approximately 2025 to 2036. These activities are all intended to be done at a single site to reduce costs and redundancies. During this time, it is anticipated that NIF will have achieved ignition, and that HiPER will have received some business investment.
See the Chapter 2 section “The Global R&D Effort on Solid-State Lasers for IFE Drivers” for more information on laser development in Europe.
FRANCE—LASER MEGAJOULE (LMJ)
The Centre lasers intenses et applications (CELIA), centered at the University of Bordeaux, organizes and administers a collaboration among French academic institutions, the Commissariat à l’énergie atomique et aux énergies alternatives
(CEA), and several other European laser collaborations. It attempts to develop relevant industrial connections for all purposes in the Bordeaux area. CELIA is heavily involved in the HiPER project. It is also a very active collaborator with other nations such as Japan and the United States on laser IFE research and with other large programs such as ITER for fusion-related materials research.
The French IFE effort other than HiPER is the Laser MégaJoule (LMJ). LMJ is similar to HiPER in one way and to NIF in a different way. Like NIF, LMJ will use a flashlamp-pumped laser as its driver. LMJ is also structurally very similar to NIF, but with differences in the number of beams and optics. It will use indirect-drive ignition and will produce approximately the same final laser wavelength of 351 nm at a similar maximum energy of 1.8 MJ. LMJ will use indirect drive for the purpose of weapons physics studies, just as NIF does. Though it is associated with the French nuclear weapons program, LMJ is to be used for open research, including IFE, 25 percent of the time, according to the present CEA Commissioner.
Currently, the CEA target laboratory is responsible for all CEA laser target needs. It has no plans to expand its capabilities for mass-production of IFE targets for the time being and will rely on General Atomics for targets for the foreseeable future. The future challenges that LMJ will face in IFE are similar to those facing other programs reliant on indirect drive: building, positioning, and orienting high-velocity targets; managing the large mass present in an indirect-drive-type target; and meeting the higher energy requirement for indirect drive ignition predicted by computer simulation.
It is planned that “first light” experiments from 162 of the intended 240 beams will occur at LMJ in 2014, with ignition experiments starting in 2017. The EU-sponsored petawatt laser arm (PETAL) will also be brought online in parallel with the main LMJ facility.
The Chinese IFE program plans to achieve ignition and burn around the year 2020. On the path to that goal, China is updating existing laser research facilities such as SG-II to higher energies and with additional features such as backlighting. The SG-III lamp-pumped Nd:glass facility is also in the process of an upgrade from 8 to 48 beams. The upgrade and construction work will culminate in completion of the 1.5 MJ (351 nm) SG-IV ignition facility.
The laser driver for the SG-IV facility is planned to be Yb:YAG water-cooled DPSSLs operating between 1 and 10 Hz and fired into a 6-m-diameter target chamber. The choice of ignition method and target has not been finalized, though fast ignition is favored with a cone-in-shell target. The indirect drive is still being considered, however. The upgrades to China’s existing laser facilities as well as new capabilities are planned to drive target physics and ignition research.
In addition to many experiments devoted to improving understanding of the physics, the Chinese program is developing its own simulation codes. This code suite will be used to design the ignition targets for China’s ignition program, and experiments to check simulation designs will be carried out on the upgraded SG-II (SG-IIU) and SG-III lasers.
JAPAN—FIREX AND I-LIFT
The Japanese Fast-Ignition Realization Experiment (FIREX) IFE facility is planning to achieve ignition using the fast ignition technique around 2019. Japan’s IFE program is also working on engineering plans for a Laboratory Inertial Fusion Test (i-LIFT) experimental IFE reactor, and it eventually plans to construct an IFE demonstration plant. i-LIFT will feature 100-kJ lasers firing at 1 Hz and a 100-kJ heating laser operating at the same rate. The facility is designed to generate net electricity.
Currently, experimental progress has been focused on fast ignition by performing integrated experiments with the FIREX-I system and the LFEX CPA heating beam. DPSSLs have been selected as the laser driver—Japan believes that its strong semiconductor industry will underpin this choice of technology. It also cites a strong domestic working relationship with the materials and MFE communities. Japan says that most critical elements of IFE reactor construction have been addressed and/or demonstrated, such as mass production of targets and high-speed target injection, magnetic field laser port protection, and liquid first-wall stability.
The current plans for i-LIFT include operation from 2021 to 2032. The Japanese anticipate that their demonstration plant will begin engineering design in 2026, and a single-chamber system will begin to operate in 2029 and will be expanded to a four-chamber commercial plant operating at 1.2 MJ at 16 Hz in 2040.
See Chapter 2 of this report for more information on laser development in Japan.
RUSSIA AND GERMANY—HEAVY ION-BASED INERTIAL FUSION ENERGY
The IFE collaboration between Russia and Germany has chosen heavy ion beams as their driver method, featuring two options. A 10-km radiofrequency linac would be needed for the heavy-ion driver. They are considering both direct fast ignition and indirect drive methods. Bi and/or Pt ion beams would drive either a rotating cylindrical target or a target similar to the capsule-in-hohlraum designs for laser-driven ignition, with a calculated gain of as much as 100. They are also examining the possibility of a fusion-fission-fusion target design using a layer of 238U.
Their proposed target chamber incorporates a two-walled design, with a wetted silicon carbide first wall and a LiPb blanket. The vapor layer generated from the
“prepulse” may mitigate a number of potential challenges such as target debris and X-ray damage to the first wall. However, the vapor generated is also a cause for concern in the overall reactor design. The radiation-hydrodynamics code RAMPHY has been used to study the effects of liquid film ablation and radiation transport, as well as other effects of importance to IFE, such as DT capsule implosion and burn, X-ray and charged particle stopping, and neutron deposition.
Experimental work with the synchrotron SIS and the Facility for Antiproton and Ion Research (FAIR) facilities in Germany is intended to investigate beam development and behavior. Other accelerator challenges to overcome include beam wobbling, vacuum instability, and high current injection. The Institute for Theoretical and Experimental Physics Terawatt Accumulator (ITEP-TWAC) project, which will be a main test bed for these issues, is now under construction.
Russia recently announced a project to build a 2.8-MJ laser for inertial confinement fusion and weapons research. The Research Institute of Experimental Physics (RFNC-VNIIEF) will develop the concept.