A new data-condensation method based on multidimensional minimisation
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K. Lassmann
Abstract
During irradiation in the Halden Reactor data such as linear rating, coolant temperature, or reactor state are routinely stored every 15 minutes, in the case of special events even at shorter time intervals. Because of the long irradiation times of up to several years, a huge amount of data is produced which is considered to be too much for direct input into fuel performance codes. In order to reduce the amount of data, various data-condensation procedures have been developed, which are briefly discussed. An innovative data-condensation method based on multidimensional minimisation is presented. The condensation factor obtained so far for Halden irradiations is 25–40, which is sufficient for a modern fuel rod performance code like TRANSURANUS. This new condensation method avoids all loss of experimental data and doubtful averaging of temperatures associated with other more drastic condensation methods. Up to now, the so-called reactor state variable, which defines the reactor operation (e. g. constant, decreasing or increasing power), has not been used. The introduction of this variable should further improve this new condensation method.
Kurzfassung
Während einer Bestrahlung im Halden Versuchsreaktor werden routinemäßig alle 15 Minuten Daten wie Stablängenleistung, Kühlmitteltemperatur (gelegentlich auch Brennstofftemperatur), Status des Reaktors, etc. gemessen und gespeichert. In speziellen Situationen werden diese Daten sogar in Sekundenabständen erfasst. Während einer mehrjährigen Bestrahlung wird so eine sehr große Datenmenge erzeugt, die nicht direkt als Eingabe für ein Brennstab-Analyse Programm verwendet werden kann. Um diese Datenmenge zu komprimieren, wurden deshalb verschiedene Algorithmen entwickelt, auf die kurz eingegangen wird. Die Nachteile existierender Algorithmen werden kurz diskutiert. In der vorliegenden Arbeit wird ein neuer Algorithmus zur Komprimierung von Daten vorgestellt, der auf einem mehrdimensionalen Minimierungsverfahren basiert. Der mit diesem Verfahren erzielte Komprimierungsfaktor beträgt etwa 25–40, was für einen modernes Brennstab-Analyse Programm wie TRANSURANUS völlig ausreichend ist. Der neue Komprimierungsalgorithmus vermeidet die Schwächen existierender Komprimierungsalgorithmen wie den Verlust von experimentellen Befunden oder die notwendig werdende zweifelhafte Mittlung von Temperaturen und bietet deutliche Vorteile. In der vorliegenden Entwicklungsstufe wird die gemessene Variable, die den Zustand des Reaktors erfasst (konstanter Betrieb, abnehmende oder zunehmende Leistung, Stillstand etc.), noch nicht verwendet. Die Verwendung dieser Variable sollte den Komprimierungsalgorithmus weiter verbessern.
References
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© 2004, Carl Hanser Verlag, München
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Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Sensitivity analysis of the Peach Bottom Turbine Trip 2 experiment
- Theoretical and experimental investigations into natural circulation behaviour in a simulated facility of the Indian PHWR under reduced inventory conditions
- A new data-condensation method based on multidimensional minimisation
- Current international activities to increase fire protection knowledge for nuclear power plants
- Simple formulas for conservatively calculating the fuel rod cladding strains due to RIA
- Accelerator driven systems for transmutation and energy production: challenges and dangers
- A method for in-situ quantification of oxygen in oil using fast neutron activation analysis
- The time-dependent effect of the biological component of 137Cs soil contamination
- Letter to the Editor
- Remarks on pulsed neutron activation
- On the critical radius of reflected spheres
