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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.
Toshihiko Yamanishi, Mikio Enoeda, Kenji Okuno, Robert H. Sherman
Fusion Science and Technology | Volume 29 | Number 2 | March 1996 | Pages 232-243
Technical Paper | Fusion Fuel Cycle | doi.org/10.13182/FST96-A30710
Articles are hosted by Taylor and Francis Online.
A control method was proposed for the cryogenic distillation column with a feedback stream. The top and bottom flow rates of the column are adjusted for the variation of external feed composition to control product purity. The flow rate of the side stream and the power of the reboiler heater are promptly and linearly changed with the corresponding variation of external feed flow rate. Ordinary columns with no feedback stream are first-order lag systems for the case where the top flow rate is chosen as a manipulated variable. On the other hand, the column with a feedback stream is a second-order lag system even in this case. The parameter-setting method of the proportional-integral (PI) controller was proposed to predict the unstable region in the control of the column. The method can also be applied to the case where the measurement of the controlled variable is accompanied by a long time lag. However, the longer time lag requires a larger integral time, and the larger integral time brings a larger overshoot and slower damping for the controlled variable. For this case, the promptness of the control can be improved by introducing the PI derivative controller.