Session JM2: Mini-conference on Nuclear Renaissance II: Where is it Going and Where Does Fusion Fit In?

Prospects for Attractive Fusion Power

During the past ten years, the ARIES Team, a national team involving universities, national laboratories, and industry, has studied a variety of magnetic fusion power plants (tokamaks, stellarators, ST, and RFP). In this paper, we present the top-level requirements and goals for commercial fusion power plants developed with consultation with US utilities and industry. We will review several ARIES designs and discuss the candidate options for physics operation regime as well engineering design of various components (e.g., choice of structural material, coolant, breeder). For each option, we will discuss (1) the potential to satisfy the requirements and goals, and (2) the critical R{\&}D needs. In particular, we will discuss fusion R{\&}D issues which are similar to those of advanced fission systems. For tokamaks, our results indicate that dramatic improvement over first-stability operation can be obtained through either utilization of high-field magnets (e.g., high-temperature superconductors) or operation in advanced-tokamak modes (e.g., reversed-shear). In particular, if full benefits of reversed-shear operation are realized, as is assumed in ARIES-AT, tokamak power plants will have a cost of electricity competitive with other sources of electricity. Emerging technologies such as advanced Baryon cycle, high-temperature superconductor, and advanced manufacturing techniques can improve the cost and attractiveness of fusion plants.   

The fusion hybrid, a new (old) development plan for fusion

For world development to proceed, mid-century energy requirements are daunting. Estimates are that by 2050, the world will need 10-30 terawatts (TW) of additional energy (we generate about 13 TW today, mostly with fossil fuel). However to avoid possibly disastrous climate change, this additional energy should be carbon-free [1]. Another study looks at how this might be accomplished [2]. The startling conclusion from Ref. [2] is that options are few, and any option would require greater changes to the world's energy systems than have occurred in the last fifty years. This paper proposes that fusion can be a player in the quest to power the mid-century world, but only by contributing to the fission/fusion hybrid. My own very preliminary study indicates that a fusion hybrid could deliver energy to the world in a timely manner, and in an economically and environmentally acceptable way. \newline \newline [1] M. Hoffert et. al., Nature, 395, 881, (1998) \newline [2] M. Hoffert et al, Science, 298, 981, (2002)   

Fusion Energy: How to realize it sooner. And with less risk.

We submit the following prescription to successfully develop fusion energy:\\ 1) Encourage competition and innovation. These are the seeds for breakthroughs. Selecting one approach at this stage is too risky.\\ 2) Pursue coherent ``complete'' programs to develop the science and technology in concert with one another.\\ 3) Make the ``end product'' of an attractive energy plant a criteria to evaluate merit.\\ 4) Set clear goals so the criteria for redirecting/ stopping the program are unambiguous.\\ 5) Reward approaches that minimize the investment needed to test the science and technology.\\ Against this background, we offer Fusion Energy with lasers and direct drive targets. Recent pellet designs suggest meaningful gains (20-60) with KrF laser energies of 500 kJ. Based on this we proposed a staged program to build the Fusion Test Facility [1]. The FTF will demonstrate the target physics and key technologies, and be flexible to accommodate advances in chambers, optics, and target physics. It would also lay the groundwork for a power plant.\\ \\ $[$1] S.P. Obenschain, et al, ``Pathway to a lower cost high repetition rate ignition facility'' Accepted in Physics of Plasmas   

Role of Advanced-Fuel and Innovative-Concept Fusion in the Nuclear Renaissance

Developing attractive fusion power requires overcoming physics, engineering, economic, and environmental obstacles. From a purely physics perspective, D-T fuel in combination with the tokamak seems most attractive. However, low-neutron advanced fuels, especially D-$^3$He, in combination with innovative confinement concepts appear very attractive from an engineering, safety, environmental, and licensing perspective. The crucial question is how advanced-fuel physics development compares to the engineering difficulties D-T fusion faces, such as tritium-breeding blanket design, neutron damage to materials, and frequent maintenance in a highly radioactive environment. With respect to physics issues, burning advanced fuels requires continued plasma physics progress and development of a suitable high-$\beta$ innovative concept. This talk will summarize the key issues---including plasma power density, surface heat flux, materials damage, activation, nuclear proliferation, and $^3$He fuel supply. Some potentially suitable innovative confinement concepts will also be described.