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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.
A. Nerem, D.H. Kellman, S.G.E. Pronko, J.R. Valentine
Fusion Science and Technology | Volume 39 | Number 2 | March 2001 | Pages 1116-1120
Plasma Engineering, Heating, and Current Drive | doi.org/10.13182/FST01-A11963394
Articles are hosted by Taylor and Francis Online.
As part of the Electron Cyclotron Heating (ECH) Facility upgrade at DIII–D an 8.4 MW Modulator/Regulator Power System was designed and constructed using acquired hardware from the Mirror Fusion Test Facility (MFTF) at Lawrence Livermore National Laboratory (LLNL) program as a foundation.1 Design changes in the feedback control of the modulator/regulator (M/R) was motivated by the need for improved output voltage regulation and improved capability to modulate the output voltage consistent with reference command signals containing modulation patterns (typically square wave). The regulation characteristics of the old ECH M/R power system had previously constrained gyrotron operation due to marginal voltage control loop stability and slow response to voltage step changes. The technical approach was to develop models of the circuit functions of the M/R controller from the circuit diagrams, and then examine the control characteristics using circuit analysis software. MATLAB® Simulink® and Intusoft IsSPICE4® (SPICE) codes were used to examine the control issues. These analysis software tools were used to simulate the controller functions and yielded identical results. The SPICE circuit model was selected as a baseline for future maintenance by the engineering staff. The analysis of the controller model blocks provided the needed information to modify the controller circuits. Changes made to the controller included addition of a voltage feedback loop around the grid driver amplifier for the power tetrode control grid in the M/R, and changes to the feedback loop compensation of the main error amplifier. The implemented revised controller performance matches the model performance predictions remarkably well. This paper describes the circuit models, implementation of the revisions to the controller, and recent operational results.
