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Johansen, M. P.*; Child, D. P.*; Collins, R.*; Cook, M.*; Davis, J.*; Hotchkis, M. A. C.*; Howard, D. L.*; Howell, N.*; Ikeda, Atsushi; Young, E.*
Science of the Total Environment, 842, p.156755_1 - 156755_11, 2022/10
Times Cited Count：4 Percentile：53.82(Environmental Sciences)Burr, T.*; Hamada, M. S.*; Howell, J.*; Suzuki, Mitsutoshi
Journal of Nuclear Science and Technology, 49(2), p.209 - 221, 2012/02
Times Cited Count：7 Percentile：48.31(Nuclear Science & Technology)Solution monitoring (SM) is a type of process monitoring (PM) intended to improve nuclear safeguards in facilities such as reprocessing plants. In SM, volume (V) and mass (M) are monitored in each tank-to-tank transfer and during all wait modes for each tank, resulting in residuals that arise by comparing observations to predictions. The main performance measure is the estimated loss detection probability (DP) for material loss scenarios. This report re-estimates DPs when realistic effects are included in simulated data, such as pump carryover, evaporation, condensation, and mixing/sparging. One challenge involves the need for SM to be part of day-to-day assessment without leading to too many alarms, so we widen the control limits to avoid alarming on innocent process variation effects.
Burr, T.*; Suzuki, Mitsutoshi; Howell, J.*; Jongo, C. E.*; Hamada, M. S.*
Nuclear Instruments and Methods in Physics Research A, 640(1), p.200 - 212, 2011/06
Times Cited Count：9 Percentile：57.01(Instruments & Instrumentation)Process monitoring (PM) is increasingly important in nuclear safeguards as a complement to mass-balance based nuclear materials accounting (NMA). Typically, PM involves more frequent but lower quality measurements than NMA. While NMA estimates special nuclear material (SNM) mass balances and uncertainties, PM often tracks SNM attributes qualitatively or in the case of solution monitoring (SM) tracks bulk mass and volume. Automatic event marking is used in several nuclear safeguards PM systems. All methods are evaluated on both raw and smoothed data, and several smoothing options are compared, including standard filters, hybrid filters, and local kernel smoothing. The main finding is that for real and simulated examples considered, a two-step strategy is most effective. First, any reasonably effective initial smoother is used to provide a good initial guess at change point locations. Second, PLR is applied, looking for one change point at a time.
Chapman, I. T.*; Buttery, R. J.*; Coda, S.*; Gerhardt, S.*; Graves, J. P.*; Howell, D. F.*; Isayama, Akihiko; La Haye, R. J.*; Liu, Y.*; Maget, P.*; et al.
Nuclear Fusion, 50(10), p.102001_1 - 102001_7, 2010/10
Times Cited Count：52 Percentile：87.41(Physics, Fluids & Plasmas)no abstracts in English
Hender, T. C.*; Wesley, J. C.*; Bialek, J.*; Bondeson, A.*; Boozer, A. H.*; Buttery, R. J.*; Garofalo, A.*; Goodman, T. P.*; Granetz, R. S.*; Gribov, Y.*; et al.
Nuclear Fusion, 47(6), p.S128 - S202, 2007/06
Times Cited Count：916 Percentile：100(Physics, Fluids & Plasmas)no abstracts in English
L
nnroth, J.-S.*; Parail, V.*; Hynnen, V.*; Johnson, T.*; Kiviniemi, T.*; Oyama, Naoyuki; Beurskens, M.*; Howell, D.*; Saibene, G.*; de Vries, P.*; et al.
Plasma Physics and Controlled Fusion, 49(3), p.273 - 295, 2007/03
Times Cited Count：15 Percentile：47.4(Physics, Fluids & Plasmas)It is investigated whether differences in the MHD stability of the pedestal, including effects of plasma rotation and aspect ratio, can explain the results of JET/JT-60U similarity experiments. As a result, these mechanisms fail to explain the experimental observations. Therefore, the effects of ripple losses on H-mode performance were investigated. The analysis shows that ripple losses of thermal ions can affect H-mode plasma performance very sensitively. Orbit-following simulations indicate that losses due to diffusive transport give rise to a wide radial distribution of enhanced ion thermal transport, whereas non-diffusive losses have a very edge-localized distribution. In predictive transport simulations with an energy sink term in the continuity equation for the ion pressure representing non-diffusive losses, reduced performance as well as an increase in the ELM frequency are demonstrated.
Parail, V. V.*; Evans, T. E.*; Johnson, T.*; Lnnroth, J.*; Oyama, Naoyuki; Saibene, G.*; Sartori, R.*; Salmi, A.*; de Vries, P.*; Becoulet, M.*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03
Ripple-induced transport and externally driven resonance magnetic perturbations (RMP) near the separatrix are considered as prospective methods of ELM mitigation in present day tokamaks and ITER. Although these methods rely on different physics to generate extra transport, the influence of this transport on plasma dynamics and ELM mitigation is either similar or supplementary. The results of extensive theoretical analysis of the underlying physics processes behind transport induced by ripple and RMP is presented together with predictive transport modelling. Comparison with experiments on present-day tokamaks is given.
Belo, P.*; Buratti, P.*; Buttery, R. J.*; Hender, T. C.*; Howell, D. F.*; Isayama, Akihiko; Joffrin, E.*; Nave, M. F. F.*; Sips, G.*
Proceedings of 31st European Physical Society Conference on Plasma Physics, Vol.28B, p.1 - 170, 2004/00
no abstracts in English
