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The objectives of MSTD are: promote the advancement of materials science in Nuclear Science Technology; support the multidisciplines which constitute it; encourage research by providing a forum for the presentation, exchange, and documentation of relevant information; promote the interaction and communication among its members; and recognize and reward its members for significant contributions to the field of materials science in nuclear technology.
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Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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Fusion Science and Technology
Latest News
ARPA-E announces $40 million to develop transmutation technologies for UNF
The Department of Energy’s Advanced Research Projects Agency–Energy (ARPA-E) announced $40 million in funding to develop cutting-edge technologies to enable the transmutation of used nuclear fuel into less-radioactive substances. According to ARPA-E, the new initiative addresses one of the agency’s core goals as outlined by Congress: to provide transformative solutions to improve the management, cleanup, and disposal of radioactive waste and spent nuclear fuel.
S. Morita, M. Goto, S. Muto, H. Y. Zhou, C. F. Dong, LHD Experiment Group
Fusion Science and Technology | Volume 58 | Number 1 | July-August 2010 | Pages 91-102
Chapter 3. Confinement and Transport | Special Issue on Large Helical Device (LHD) | doi.org/10.13182/FST10-A10796
Articles are hosted by Taylor and Francis Online.
Impurity transport has been studied in the Large Helical Device (LHD) with different diagnostic approaches based on an active method that combine carbon pellet injection with visible bremsstrahlung measurement and three passive methods for radial profile measurements of Ar and Fe K X-ray lines, Zeff, and extreme ultraviolet (EUV, 500 Å) impurity line emissions, in addition to usual passive spectroscopy. The existence of an inward convective velocity is confirmed in the edge region ( > 0.6) using the active method, whereas no convection is required in the core region ( < 0.6). The electron density dependence is weak for the diffusion coefficient (typically D = 0.15 to 0.25 m2 /s) for densities of 1 to 5 × 1013 cm-3 but is strong for the inward convective velocity, which varies in the range of V(a) = -0.2 to -1.5 m/s. The inward V in helium plasmas (-0.4 m/s at = 0.8 and the central density, ne [approximately] 4.0 × 1013 cm-3) is nearly half that in hydrogen plasmas (-0.7 m/s). This difference suggests a charge state dependence of fuel ions predicted by the neoclassical theory. Radial profiles of impurity transport coefficients of argon and iron have been studied using spatially resolved soft X-ray pulse-height analyzers. The impurity transport has also been studied in extremely high density discharges achieved by H2 pellet injection based on the passive spectroscopy and Zeff profile measurement. A flat Zeff profile is obtained at ne = 2.5 × 1014 cm-3 with values of 1.1 Zeff 1.2, suggesting no existence of impurity accumulation and radially constant impurity partial pressure. Finally, radial profiles of impurity lines in the EUV range are analyzed with the transport coefficients.