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Fusion Science and Technology
Latest News
Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
Fong-Yan Gang, D. J. Sigmar, Jean-Noel Leboeuf, Fredrik Wising
Fusion Science and Technology | Volume 25 | Number 3 | May 1994 | Pages 266-277
Technical Paper | Alpha-Particle Special / Plasma Engineering | doi.org/10.13182/FST94-A30283
Articles are hosted by Taylor and Francis Online.
Recent developments in computational and theoretical studies of alpha-particle-driven Alfvén turbulence in both the long (k⊥ρi ≪ 1) and the short (k⊥ρi ≤ 1) wavelength regimes are reported. In the long wavelength regime, a hybrid particle-fluid model is solved numerically as well as analytically in a simple slab geometry. The dominant nonlinear interactions are found to be couplings between two Alfvén waves to generate a zero-frequency electromagnetic convective cell and strong E × B convection of resonant alpha particles, which result in significant changes in plasma equilibria. The fluctuation energies first increase, then saturate and decay. The alpha-particle transport is convective and significant but does not necessarily lead to an appreciable alpha-particle loss. A mode-coupling theory is developed to explain the simulation results. In the short wavelength regime, a reduced turbulence model that describes the coupled nonlinear evolutions of fluctuation spectrum and alpha-particle density profile nα(r,t) in the presence of an alpha-particle source Sα(r, t) is solved numerically. A steady state is achieved. The nonlinear saturation is due to ion Compton scattering-induced energy transfer to higher wave numbers. Alpha-particle transport is significant, and a diffusion coefficient of Dα ≃ 0.5 m2/s for International Thermonuclear Experimental Reactor (ITER)-like parameters is obtained. The effect of anomalous alpha-particle diffusion on alpha-particle power coupling to bulk plasmas is also discussed.