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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.
David D. B. van Bragt, Tim H. J. J. van der Hagen
Nuclear Technology | Volume 121 | Number 1 | January 1998 | Pages 52-62
Technical Paper | Reactor Safety | doi.org/10.13182/NT98-A2818
Articles are hosted by Taylor and Francis Online.
A parametric study of coupled neutronic-thermohydraulic stability of natural circulation boiling water reactors (BWRs) is performed. As an example, the stability characteristics of the Dutch Dodewaard reactor, which was cooled by natural circulation, are determined. The Dodewaard reactor can be considered as the prototype of next generation natural circulation BWRs. The stability issues that are identified for this prototype reactor are therefore important in the design of new natural circulation BWRs.Without a riser section installed, only one region of thermohydraulic instability exists in the stability plane. The significant gravitational pressure drop in a riser section, installed to enhance the natural circulation flow, gives rise to the emergence of an additional region of instability. The oscillations in this zone become especially important during low-power/low-pressure (reactor startup) conditions. Significant damping of these oscillations occurs in a reactor, due to the nuclear void reactivity feedback.A comparison between natural circulation in-phase and out-of-phase reactor stability is made, in particular important for large reactor cores but also yielding unexpected results for small reactors. The impact of downcomer inertia on the stability of the in-phase mode is investigated in detail. Typical trajectories in the dimensionless stability plane are calculated as a function of changing operating conditions, to investigate their influence on reactor dynamics.