Uncontrolled withdrawal of a control rod without SCRAM
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T. Abou-El-Maaty
Abstract
In the present work, the thermal-hydraulic analysis of reactivity-induced transients in a Low Enriched Uranium (LEU) core of a typical material test research reactor is conducted using the previous program developed Khater et al. The analysis was done for the uncontrolled withdrawal of a control rod under scram-disabled conditions. The initiating event reactivity was considered with and without influence of the reactivity efficiency curve (“S” curve). The results of the transient calculations are analyzed and compared with each other. In the transient without the “S” curve influence, a high primary peak power of 406.18 MW is attained and a clad melt down is occurring after 1.85 s. In the transient with the “S” curve influence, a super prompt highly critical situation is produced (1.762 $ at 0.895 s) with a very high primary peak power of 801.05 MW at 0.912 s. A fast clad melt down is resulting in the hot channel at 1.088 s and a stable film boiling is occurring. This study shows that the influence of the reactivity efficiency curve results in higher peaks in power and temperatures (fuel, clad and coolant) with a fast clad melt down than that of a linear assumption.
Kurzfassung
In der vorliegenden Arbeit wurden die reaktivitäts-induzierten Transienten in einem Kern mit niedrig angereichertem Uran eines typischen Materialtest-Forschungsreaktors mit Hilfe des zuvor entwickelten Rechencodes ETRR2-RIA thermohydraulisch analysiert. Die Analyse wurde für den Fall eines unkontrollierten Herausziehens eines Regelstabes ohne SCRAM durchgeführt. Die bei diesem Ereignis freigesetzte Reaktivität wurde mit und ohne den Einfluss der Reaktivitätsleistungskurve (“S“-Kurve) betrachtet. Die Ergebnisse der Transientenberechnung werden analysiert und miteinander verglichen. Bei der Transiente ohne “S“-Kurven-Einfluss wird eine promptkritischer Zustand (1,762 $ bei 0,895 s) mit einer sehr hohen primären Leistungsspitze von 801,05 MW nach 0,912 s erzeugt. Dies verursacht ein schnelles Schmelzen der Hüllrohre im Heißkanal nach 1,088 s und ein stabiles Filmsieden. Diese Studie zeigt, dass der Einfluss der Reaktivitätsleistungskurve zu höheren Leistungs- und Temperaturspitzen (Brennstoff, Hüllrohre und Kühlmittel) mit einem schnelleren Schmelzen der Hüllrohre führt als dies bei einer linearen Annahme der Fall ist.
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© 2007, Carl Hanser Verlag, München
Artikel in diesem Heft
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Effect of fuel particles' size and position variations on multiplication factor in pebble-bed nuclear reactors
- Axial flux harmonics affecting the parallel channel instabilities in boiling water reactors
- Uncontrolled withdrawal of a control rod without SCRAM
- Modelling of Carbon-14, Iodine-129 and Cesium-137 releases from near surface radioactive waste disposal and their impact on environment and humans
- Investigation of nuclear model predictions for proton induced reaction cross-sections up to 150 MeV
- The extension of the 2-D finite element/boundary element hybrid method to general multigroup neutron diffusion theory
- Extension of the HN method for solving radiation transfer problems in plane geometry for general anisotropic scattering
- The albedo problem for pure-triplet scattering
- Studies on the transmission and processing of pulse-shaped signals from nuclear radiation detectors using methods of systems theory
- The preignition problem in nuclear explosive devices (NEDs) for a sigmoidal Rossi-α and a high neutron background
- Comparison of economy and emissions of nuclear power plants and combined gas and wind electricity generators
Artikel in diesem Heft
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Effect of fuel particles' size and position variations on multiplication factor in pebble-bed nuclear reactors
- Axial flux harmonics affecting the parallel channel instabilities in boiling water reactors
- Uncontrolled withdrawal of a control rod without SCRAM
- Modelling of Carbon-14, Iodine-129 and Cesium-137 releases from near surface radioactive waste disposal and their impact on environment and humans
- Investigation of nuclear model predictions for proton induced reaction cross-sections up to 150 MeV
- The extension of the 2-D finite element/boundary element hybrid method to general multigroup neutron diffusion theory
- Extension of the HN method for solving radiation transfer problems in plane geometry for general anisotropic scattering
- The albedo problem for pure-triplet scattering
- Studies on the transmission and processing of pulse-shaped signals from nuclear radiation detectors using methods of systems theory
- The preignition problem in nuclear explosive devices (NEDs) for a sigmoidal Rossi-α and a high neutron background
- Comparison of economy and emissions of nuclear power plants and combined gas and wind electricity generators
