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- Broggio, D., et al.
(författare)
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Child and adult thyroid monitoring after a reactor accident (CAThyMARA): Technical recommendations and remaining gaps
- 2019
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 128:Septemberg
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Tidskriftsartikel (refereegranskat)abstract
- © 2019 Elsevier Ltd Following a severe nuclear reactor accident large amounts of radioactive iodine are released in the atmosphere. Health consequences estimation for the affected population is based on the dose assessment which can be derived from in vivo measurements. Since the uptake of radioactive iodine increases the thyroid cancer risk of children it is of particular interest to dispose of technical recommendations on thyroid monitoring, particularly for children. This paper summarizes recommendations that have been issued by a group of European radiation protection specialists during the CAThyMARA project. It covers technical aspects such as the choice of instruments, the calibration process, the measurement preparedness, the dose assessment and communication issues. This paper also discusses remaining gaps and serves as an introduction to other papers of this special issue.
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| 5. |
- Brunsell, Per, et al.
(författare)
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Feedback Stabilization of Multiple Resistive Wall Modes
- 2004
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 93:22, s. 225001-
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Tidskriftsartikel (refereegranskat)abstract
- Active feedback stabilization of multiple independent resistive wall modes is experimentally demonstrated in a reversed-field pinch plasma. A reproducible simultaneous suppression of several nonresonant resistive wall modes is achieved. Coupling of different modes due to the limited number of the feedback coils is observed in agreement with theory. The feedback stabilization of nonresonant RWMs also has an effect on tearing modes that are resonant in the central plasma, leading to a significant prolongation of the discharge pulse.
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| 7. |
- Cavinato, M., et al.
(författare)
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Comparison of strategies and regulator design for active control of MHD modes
- 2005
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Ingår i: Fusion engineering and design. - : Elsevier BV. - 0920-3796 .- 1873-7196. ; 74:1-4, s. 549-553
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Tidskriftsartikel (refereegranskat)abstract
- A system of evenly spaced poloidal arrays of saddle coils was recently installed on the reversed field pinch device EXTRAP T2R to perform experiments on the active control of MHD modes. The implementation of different control strategies, such as "intelligent shell" and "mode control", was made possible by a flexible digital control system. After giving some results on the performances of the innermost coil current control loop, two versions of "mode control" recently tested on the machine are presented. In the "wise shell" approach, equilibrium related modes are ruled out and a systematic increase of the pulse length is obtained. In a second, more model based, approach, a mode estimator/controller is designed aiming at a full state feedback by including modes, which are not directly measurable due to the limited number of available real-time signals.
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| 10. |
- Gregoratto, D., et al.
(författare)
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Optimisation of Resistive Wall Mode Control in Reversed Field Pinches
- 2004
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Ingår i: Nuclear Fusion. - 1741-4326 .- 0029-5515. ; 44, s. 1-
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Tidskriftsartikel (refereegranskat)abstract
- Feedback stabilization of magnetohydrodynamic modes in reversed field pinches is analysed for a set of discrete coils driven by voltage control. It is found that the resistive wall mode can be stabilized with a very simple controller structure and with acceptable voltages in the coils. These results are obtained by using a sufficient number of active coils and either sensors for the radial field or sensors for the poloidal or toroidal field placed inside the resistive wall. The result is robust with respect to variations in the plasma equilibrium. Poloidal and toroidal sensors placed outside the wall require a more complicated controller and very high voltages, and do not allow as good control performance as internal sensors.
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| 11. |
- Liu, Yueqiang, 1971, et al.
(författare)
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Feedback Control of Resistive Wall Modes in Toroidal Devices
- 2004
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 44:1, s. 77-86
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Tidskriftsartikel (refereegranskat)abstract
- Feedback control of nonaxisymmetric resistive wall modes is studied analytically for cylindrical plasmas and computationally for high beta tokamaks. Internal poloidal sensors give superior performance to radial sensors, for instance in terms of the highest achievable plasma pressure. A single poloidal array of feedback coils allows robust control with respect to variations in plasma pressure, current and rotation velocity. The control analysis is applied to advanced scenarios for ITER. Configurations with multiple poloidal coils and feedback systems for nonresonant MHD instabilities in reversed field pinches are also studied. The control study was carried out using the assumption of ideal amplifiers.
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