R&D Category: Commissioning and start-up testing, rise to power, transient testing
3 documents found
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Investigations concerning gas entrainment at KNK II. Untersuchungen zum Gaseintrag an KNK II
Hoppe, P.;Massier, H.;Mitzel, F.;Vaeth, WKernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Projekt Schneller Brueter
KFK--2867 - German - 1979
Abstract: During commissioning of KNK II operational difficulties were encountered due to gas entrainment in the coolant. This gas entrainment caused negative reactivity fluctuations which tripped the reactor repeatedly. Since first investigations indicated one main cause of the gas entrainment and the existence of an accumulation process a technical modification (installation of a throttle valve) for remedy was performed. By means of this valve the gas entrainment could be considerably reduced but not completely eliminated. The gas storages can be localized with high probability to a region in the primary coolant circuit between a special throttle device and the lower part of the fuel elements. A permanent gas entrainment could be detected even at operational plant conditions (40% reactor power) at which no scrams due to entrained gas bubbles have been encountered. The volume fraction referred to the coolant volume in the core was estimated to be at least 10-4. The observation of apparently positive reactivity overshoots is due to the application of an erroneous reactivity to power transfer function for the reactivity calculation. From the use of the measured reactivity to power transfer function it can be concluded that only negative reactivity fluctuations are induced by gas bubbles passing the core. (orig./HP)
Key words: entrainment;fluctuations;gases;knk-2 reactor;reactivity;reactor commissioning;reactor operation;reactor start-up;valves
Components Category: Reactor components
display the document: 11514378.pdf
Identification of vibrational effects in KNK II fuel elements
Vaeth, W.;Mitzel, F.;Ansari, SKernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Neutronenphysik und Reaktortechnik;Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Projekt Schneller Brueter
KFK--3157 - English - 1981
Abstract: Several observations indicate vibrational effects in some fuel elements of the KNK-II core. This report describes how the coolant outlet temperature of each fuel element was used successfully as a means of the identification of these vibrations. As a result the cause of the sharp peaks in the power spectral density of the KNK-II reactivity noise was found. (orig.)
Key words: correlations;frequency dependence;fuel elements;knk-2 reactor;measuring methods;mechanical vibrations;neutron flux;reactivity;reactor cores;reactor noise;spectral density;temperature dependence;thermocouples
Components Category: --Fuel assemblies
display the document: 13650951.pdf
Determination of radionuclides in the primary sodium and in the primary cover gas Argon and of the Tritium content of the ternary water-/steam circuit of KNK II at the start-up of the second core Bestimmung von Radionukliden im Primaernatrium, im primaeren Schutzgas Argon und von Tritium im tertiaeren Wasser-/Dampfkreislauf der KNK-II bei der Inbetriebnahme des Zweitkerns
Stamm, H.-H.;Hanke, H.-D.;Clauss, H.;Schmidt, KKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.17P11A - German - 1983
Abstract: During the start-up operation of KNK II with its second core the plant was operated at power levels of 40, 80 and 100 % for several days each. During this phase a radiochemical program was performed with measurements of the radionuclide content in the primary sodium and primary cover gas Ar and of the Tritium content of the ternary water-/steam circuit. The results of these measurements are described in this report
Key words: argon;cover gas;knk-2 reactor;primary coolant circuits;radiochemical analysis;secondary coolant circuits;sodium;tritium
Components Category: -Coolant, cover-gas and Primary cooling system including heat exchangers
display the document: 34086278.pdf