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The busyness of the nuclear fuel supply chain
Ken Petersenpresident@ans.org
With all that is happening in the industry these days, the nuclear fuel supply chain is still a hot topic. The Russian assault in Ukraine continues to upend the “where” and “how” of attaining nuclear fuel—and it has also motivated U.S. legislators to act.
Two years into the Russian war with Ukraine, things are different. The Inflation Reduction Act was passed in 2022, authorizing $700 million in funding to support production of high-assay low-enriched uranium in the United States. Meanwhile, the Department of Energy this January issued a $500 million request for proposals to stimulate new HALEU production. The Emergency National Security Supplemental Appropriations Act of 2024 includes $2.7 billion in funding for new uranium enrichment production. This funding was diverted from the Civil Nuclear Credits program and will only be released if there is a ban on importing Russian uranium into the United States—which could happen by the time this column is published, as legislation that bans Russian uranium has passed the House as of this writing and is headed for the Senate. Also being considered is legislation that would sanction Russian uranium. Alternatively, the Biden-Harris administration may choose to ban Russian uranium without legislation in order to obtain access to the $2.7 billion in funding.
Yuichi Ogawa, Nobuyuki Inoue, Zensho Yoshida, Kunihiko Okano
Fusion Science and Technology | Volume 24 | Number 2 | September 1993 | Pages 188-199
Technical Paper | Plasma Engineering | doi.org/10.13182/FST93-A30225
Articles are hosted by Taylor and Francis Online.
The plasma and machine parameters of a pulsed tokamak reactor with a day-long operation period have been studied, where engineering constraints such as maximum toroidal field strength are preserved at International Thermonuclear Experimental Reactor (ITER) levels so as to realize a fusion reactor with only a short-range extension of currently available technology. To provide the magnetic flux necessary to sustain a plasma current inductively for 1 day or longer, plasmas with a major radius of R > 9.5 m are necessary, and a plasma with an aspect ratio as high as A > 5 should be employed. Typical parameters are as follows: major radius R = 10 m, minor radius a = 1.85 m, plasma elongation κ = 1.8, plasma current Ip = 12.2MA, toroidal field on axis Bt >= 7.56 T, and safety factor at the plasma surface qψ = 3. A plasma volume V ∼ 1200 m3 is comparable with that of ITER, even though the major radius of a day-long operation reactor is relatively large. A very small amount of heating power (∼ 15 MW) with a heating time of only a few tens of seconds is sufficient to achieve the ignition condition. This is well within the capacity of auxiliary heating systems currently used in large tokamak devices. A confinement improvement factor (from L mode) of fL > 1.7 is required to design a reactor with a reasonable machine size and a day-long pulse duration. The operation temperature is chosen to be 〈T〉 = 20 keV with a toroidal beta βt = 2.6% (Troyon factor g = 3), which gives a fusion power Pfus = 2.5 GW even for an alpha-particle dilution nα/ne of 10%. The bootstrap current fraction is 50% or more of the total current, and current profile needed for the beta limit could be achieved with a combination ofohmic current in the plasma center region and bootstrap current in the outer region. If the maximum toroidal field is set much higher, as in proposed recent reactor designs for the Steady-State Tokamak Reactor (SSTR) and ARIES, a more attractive plasma with a larger safety factor can be designed, and the pulse length can be extended remarkably.