R&D Category: Safety aspects
43 documents found
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Heat transfer calculations on the KNK II emergency cooling system Waermetechnische Rechnungen zum KNK II Notkuehlsystem
Vossebrecker, H.;Groenefeld, GINTERATOM GmbH, Bergisch-Gladbach (Germany)
IA-ITB--76.130 - German - 1976
Abstract: The Licensing Authority had demanded that in case of the change of the KNK thermal core into a fast core the decay heat removal system must be improved by a diverse and spatially separated emergency cooling system. In order to meet this requirement an existing nitrogen system of the facility is extended in such a manner that the decay heat will be removed by a nitrogen flow passing through the gap between reactor vessel and guard vessel. The heat transport from the core to the vessel is accomplished by natural convection flow rates which are generated by density differences between the hot core subassemblies, the reflector subassemblies and other passages between the upper and the lower plenum. The calculations show that the maximum temperatures in the core do not reach the sodium boiling-point. The maximum vessel temperature is 673 deg. C. In this report the function of the emergency cooling system and the methods of calculation are described, the input data and the results are stated and it is shown that the calculated temperatures are conservative
Key words: after-heat removal;boiling points;eccs;heat transfer;knk-2 reactor;natural convection;reactor cores;reactor vessels;safety analysis;sodium
Components Category: -Decay heat removal systems
display the document: 34087422.pdf
Basic concept and design data of a nuclear sodium boiling experiments in KNK II Grundkonzept und Auslegungsdaten eines nuklearen Na-Siedeversuches in KNK
Edelmann, MKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-INR--1.24.3/5 - German - 1976
Abstract: On the basis of investigations within a feasibility study, the report describes the concept of a nuclear boiling generator as well as aspects of the nuclear and thermal-hydraulic design and instrumentation of a sodium boiling experiment in KNK II. In addition to the problems resulting from the feasibility study, first results of design calculations are presented. Therewith a common basis of available data for the solution of open questions is provided to the institutions participating in this project
Key words: boiling detection;calculation methods;design;feasibility studies;knk-2 reactor;measuring instruments;sodium;thermal hydraulics
Components Category: -Core components
display the document: 34087743.pdf
Safety aspects about the installation of a nuclear boiling generator in KNK II Sicherheitstechnische Gesichtspunkte beim Einsatz eines nuklearen Siedegenerators in KNK II
Mitzel, FKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-INR--01.24.3/11 - German - 1977
Abstract: In this report the safety problems are described which are related to the installation of a nuclear boiling generator in KNK II. Key problems are the stress of the cladding and the safety instrumentation. Stress analysis and out-of-pile experiments so far indicate that the cladding material to be used should withstand the stresses during local boiling. The stress and strain as well as the creep and fatigue behavior due to temperature oscillations should however still be analyzed more accurately on the basis of improved material coefficients. This might not be necessary, if it can be proved, that the out-of-pile experiments give complete information about the behavior of the cladding in the nuclear generator. The instrumentation being proposed is suitable for controlling the boiling process, under the condition that the results from out-of-pile experiments can reliably be used for temperature calculations in the nuclear boiling generator. This has still to be checked. The influences of the boiling generator on possible reactor malfunctions, to be kept under control by the automatic reactor shutdown system, and on reactivity coefficients are compatible with the requirements of the reactor safety. The same holds for the special design of the boiling generator in order to limit the damage in the very unlikely event of a failure
Key words: boiling detection;creep;engineered safety systems;in core instruments;knk-2 reactor;reactivity coefficients;safety analysis;stress analysis;thermal fatigue
Components Category: any or undefined
display the document: 34087741.pdf
Feasibility study of a sodium boiling experiment at KNK II at nuclear power Studie zur Durchfuehrbarkeit eines Na-Siedeversuchs in der KNK II mit nuklearer Leistung
Edelmann, M.;Artz, D.;Bestenreiner, G.;Dorr, B.;Erhardt, J.;Hoppe, P.;Huber, F.;Kempe, H.;Mitzel, F.;Reimann, G.;Ricken, E.;Schaefer, L.;Schleisiek, K.;Schwarz, M.;Seitz, H.;Steinbock, K.;Vaeth, W.;Venker, H.;Zihla, WKernforschungszentrum Karlsruhe GmbH (Germany), INTERATOM;Bergisch-Gladbach (Germany)
KFK-INR--01.24.3 - German - 1977
Abstract: For testing of all potential methods to detect sodium boiling in LMFBR subassemblies, a sodium boiling experiment at KNK II is under consideration. Local boiling of sodium is to be produced behind an artificial blockage in a modified fuel element of the fast test zone of KNK II to provide approximate prototype reactor environment and operating conditions. This paper consists of a summary report on the proposed project and the results of the feasibility study and of 13 single contributions dealing with key items of the experiment. As a conclusion, the proposed experiment appears feasible and is not unlikely to be licensed by the authorities
Key words: boiling detection;experiment planning;feasibility studies;flow blockage;fuel elements;knk-2 reactor;sodium
Components Category: -Core components
display the document: 34087740.pdf
Instrumentation, threshold and signal processing for the nuclear boiling generator of KNK II Instrumentierung, Grenzwerte und Signalverarbeitung fuer den nuklearen Siedegenerator an KNK II
Erhardt, J.;Hoppe, PKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-INR--1.24.3/7 - German - 1977
Abstract: It is investigated in this report, which measuring data recorder are suitable for the control of the respective operational state and for the observation of the boiling process in the planned nuclear boiling generator of KNK II. The expected behaviour of the different measuring parameters during normal and test operation is estimated. With consideration of the irradiation and temperature loadings at the place of operation, the requirements for the data recorders are formulated and compared with the specifications of available devices. Hereby, it became obvious that a redundant and diverse safety instrumentation with flow-meters, thermocouples and neutron detectors is feasible. A threshold management for the safety relevant measuring data is proposed and a constructional arrangement of all data recorders in the instrumented plug of KNK II is given
Key words: boiling detection;data processing;feasibility studies;flowmeters;knk-2 reactor;neutron detectors;reactor monitoring systems;reactor safety;signal conditioning;thermocouples
Components Category: -Core components
display the document: 34087744.pdf
Detection of local sodium boiling in the nuclear boiling generator in KNK II and in the cores of SNR 300 and SNR 2 Nachweis von lokalem Na-Sieden im nuklearen Siedegenerator an der KNK II sowie im Core des SNR 300 und SNR 2
Erhardt, J.;Hoppe, PKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-INR--1.24.3/9 - German - 1977
Abstract: As a basis of a global detection system, the detection of local boiling in sodium cooled reactors via surveillance of the neutron flux background noise is of special importance. With the help of parameter studies it is investigated in the present report, which parts of the core of SNR 300 and SNR 2 could be monitored with such a detection system. As a comparison the detection sensibility of the planned boiling generator in KNK II is determined
Key words: boiling detection;knk-2 reactor;neutron flux;reactor monitoring systems;reactor noise;reactor safety;snr reactor;snr-2 reactor
Components Category: -Core components
display the document: 34087745.pdf
Local coolant flow perturbations in KNK II - coolant inlet blockages of assemblies of the test and driver zone Lokale Kuehlflusstoerungen in KNK II - Kuehlmitteleinlaufblockaden von Elementen der Test- und Treiber-zone
Duesing;Friedel;GerlingINTERATOM GmbH, Bergisch-Gladbach (Germany)
IA--70.670.4 - German - 1978
Abstract: The present report documents the investigations of local coolant blockages, which were requested for KNK II from the licensing authorities. Sudden blockages at the coolant inlet of fuel assemblies are assumed of such a degree that sodium boiling occurs. Four basic cases have been defined, three for the central fuel assembly with different nominal power levels and different residual coolant flow and one for a moderated driver assembly with 100% power and 10% residual flow. For these cases the course of the accident has to be followed for each scram excitation into the post-scram phase. It had to be proved, that these perturbations are controlled by the inherent properties and the preventive safety measures of the KNK II and that their extension is prevented. It is shown that this proof target is reached. From the calculational results for the basic cases statements are deduced for the accident detection and the accident course for the whole spectrum of integral coolant flow reduction accidents. The aimed high efficiency of the preventive measures, especially in the test zone, is hereby confirmed
Key words: boiling;flow blockage;fluid flow;knk-2 reactor;loss of flow;reactor accidents;risk assessment;safety analysis;scram;sodium
Components Category: -Core components
display the document: 34087395.pdf
Vibration measurements at KNK II Schwingungsmessungen an KNK II
Hoppe, P.;Massier, H.;Mitzel, F.;Vaeth, WKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.18P05D - German - 1979
Abstract: For the development of surveillance techniques, vibration measurements have been performed at the sodium cooled fast reactor KNK II. For this purpose the signals of neutron detectors, sodium pressure gauges, displacement transducers and strain gauges, some of them being installed within the core, have been analyzed by means of noise analysis methods. The power spectral densities of the neutron flux and the sodium pressure show distinct correlated peaks indicating vibrations of core internals
Key words: fuel assemblies;knk-2 reactor;mechanical vibrations;neutron detectors;performance testing;reactor cores;reactor noise;sodium;strains;transducers
Components Category: -Core components
display the document: 34086289.pdf
Investigations of gas entrainment in KNK II Untersuchungen zum Gaseintrag an KNK II
Hoppe, P.;Massier, H.;Mitzel, F.;Vaeth, WKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.18P25A - 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. This report describes the investigations made after the plant modification. The main objective was to test the effectiveness of the modifications and to look into the following still open problems: Localization of the gas storage, detection and estimation of a permanent gas entrainment and the analysis of positive power overshoots being observed in connection with the gas bubbles
Key words: bubbles;entrainment;gases;knk-2 reactor;performance testing;reactivity insertions;reactor accidents
Components Category: -Core components
display the document: 34086291.pdf
Detection of local cooling disturbances in the core of SNR 300 by Delayed Neutron Detection DND and by fuel element outlet temperature surveillance Detektion lokaler Kuehlungsstoerungen im Kern des SNR 300 durch DND-System und Ueberwachung der Brennelementaustrittstemperatur
Schleisiek, KKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.19P21A - German - 1979
Abstract: In this report the possibilities of the detection of local cooling disturbances in the core of SNR 300 by Delayed Neutron Detection DND and fuel element outlet temperature monitoring are analyzed. At the given DND scram level of 150 cm2 effective free fuel surface in the most unfavourable zone of the core, the fuel mass within a local blockage will not exceed 120 g. In the MOL 7C experiments it has been demonstrated that blockages of this size do not have the potential for a fast failure propagation to the fuel element as a whole. The local destruction of fuel pins after the occurrence of dry-out within a local blockage is reliably detected by the DND system with a time delay corresponding to the sodium transport time to the DND monitor. Even at a fast reduction of the sodium flow leading to bulk boiling and melting in the fuel element, DND signals can be expected which are sufficient to initiate a reactor scram. Many events of the propagation process cause a temperature increase at the fuel element outlet, too. In most cases however, the DND is superior to the temperature surveillance with respect to the sensitivity, except for blockages at the fuel element inlet. In this case a distinct temperature signal can be expected prior to the occurrence of pin failures as a consequence of the temperature increase
Key words: delayed neutron analysis;dryout;flow blockage;fuel element failure;knk-2 reactor;neutron detection;reactor accidents;snr reactor;sodium;temperature monitoring
Components Category: -Core components
display the document: 34086297.pdf
Investigation of different reactor protection systems Untersuchung verschiedener Reaktorschutzsysteme
Eggenberger, O.;Gmeiner, L.;Nehmer, J.;Racke, W.;Voges, UKernforschungszentrum Karlsruhe GmbH (Germany)
PSB--01.02.19P23A - German - 1979
Abstract: It is the goal of this report to evaluate and to compare the computerized reactor protection systems of different existing plants and to develop a methodology for application in fast reactors and to be tested in KNK II. Within the 14 plants under investigation four are fast reactors and the others are thermal reactors
Key words: computerized control systems;fast reactors;knk-2 reactor;performance testing;reactor protection systems;thermal reactors
Components Category: -Protective and shut-down systems (shutdown rods and drive mechanisms, passive control systems, support systems)
display the document: 34086370.pdf
Investigations of the gas passage through the reactor core of KNK II Untersuchungen zu den Gasdurchlaeufen durch den Reaktorkern KNK II
Hoechel, J.;Schott, HINTERATOM GmbH, Bergisch-Gladbach (Germany)
IA-INTAT--75.01284.1 - German - 1980
Abstract: During the startup phase of KNK II automatic scrams due to the signal 'reactivity too low' occurred when a power level above 60 % was reached. Comprehensive plant experiments at zero power were performed to find out the reason for the reactivity effects. It became clear that the transport of gas bubbles through the core was the reason. With the help of several further experiments it could be shown that the gas discharge pipe of the nozzle modification equipment was the major gas source. After reduction of the mass-flow through this pipe with the help of a throttle, a stationary operation of the plant was possible. This report describes the results of the experimental investigations at the plant in the frame of the experimental operation and those which were performed in parallel on different water models
Key words: entrainment;fuel elements;gases;knk-2 reactor;reactivity insertions;reactor cores;reactor operation
Components Category: -Core components
display the document: 34087407.pdf
Model experiments for the problem of the gas storage and gas transport in the KNK reactor Modellversuche zum Problem der Gasspeicherung und des Gastransports im KNK-Reaktor
Voj, P.;Granner, N.;Penny, WINTERATOM GmbH, Bergisch-Gladbach (Germany)
IA-INTAT--53.03970.1 - German - 1980
Abstract: During the start-up phase of KNK II an automatic scram due to the signal 'negative reactivity high' occurred at a power level of 64%. The reactivity threshold of the reactimeters was at -7.3 cent. In the frame of the examinations of the cause for the scram it was found out, that mechanical changes in the core area were not the reason. Since further scrams occurred, specific plant experiments at zero power were performed with the result, that gas transported with the sodium was identified as the origin of the reactivity perturbations. It could be shown, that the gas quantities under discussion were no safety related problem. But they reduced the availability of the plant and limited the frame of the planned operational procedures of the test reactor. This report presents the results of model experiments in water, which were performed in parallel to the plant experiments
Key words: entrainment;gases;knk-2 reactor;reactivity meters;reactivity;reactor start-up;sodium
Components Category: -Core components
display the document: 34087403.pdf
Safety related investigations for the second and third operation period of KNK II Sicherheitstechnische Untersuchungen fuer die zweite und dritte Betriebsperiode der KNK II
Friedel, G.;Groenefeld, G.;Lenzen, M.;Niebel, H.;Pueschel, H.;Schade, H.-J.;Stepan, GINTERATOM GmbH, Bergisch-Gladbach (Germany)
IA-ITB--70.01486.9 - German - 1980
Abstract: The present report contains the safety analysis performed for the second core of KNK II in the operation period from 256 to 710 equivalent full-power days. It is separated into the following six chapters: 1. Operational and accidental performance. 2. Local cooling flow disturbations. 3. Operational and accidental behavior of the primary heat transfer circuits. 4. Investigation of the emergency cooling performance. 5. Thermo-technical investigations of the fuel assemblies during handling. 6. Activities in the plant and radiological effects in case of normal operation and accidents
Key words: dynamics;eccs;fluid flow;fuel assemblies;heat transfer;knk-2 reactor;primary coolant circuits;radiation protection;reactor cores;safety analysis;steady-state conditions;thermal analysis;transients
Components Category: -Core components
display the document: 34087418.pdf
Analysis of reactivity noise measured at KNK II with respect to vibrations of control rods and primary loop components
Mitzel, F.;Ansary, S.;Vaeth, W. (Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.))INIS-mf--8131 - English - 1981
Abstract: not available
Key words: control elements;knk-2 reactor;mechanical vibrations;primary coolant circuits;reactivity insertions;reactor noise
Components Category: -Protective and shut-down systems (shutdown rods and drive mechanisms, passive control systems, support systems)
display the document: 14755895.pdf
Potential and state of development of acoustic boiling detection methods in sodium cooled reactors Potential und Entwicklungsstand akustischer Messverfahren zur Siededetektion in natriumgekuehlten Reaktoren
Rohrbacher, H.A.;Schleisiek, KKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.18P61A - German - 1981
Abstract: In sodium cooled reactors the application of acoustic measuring methods offers a number of new and redundant possibilities for an immediate boiling detection of the coolant. The reliability and availability of an acoustic surveillance system is substantially determined by the reactors background, the composition of the boiling spectra and their local intensity as well as by the property of the high temperature sensors. The physical process of boiling, the complex acoustic transfer function, the attenuation and delay times are described. With an assessment of the emitted acoustic energies of collapsing sodium vapour bubbles a statement is made for the absolute pressure of the acoustic signals in comparison to the experimentally measured background data of a reactor providing a realistic signal-to-noise figure. It is shown that the absolute values of acoustic pressure signals from out-of-pile boiling experiments under reactor-like conditions are in good conformity to the theoretical calculations. The choice of suitable acoustic sensors for reactor application is of great importance. The advantage and drawback of different kinds of microphones are discussed in consideration to high ambient temperatures and irradiation doses. An automatically working acoustic surveillance system of the core can be realized by an on-line-data processing system whose principal structure is described
Key words: acoustic measurements;background noise;boiling detection;bubbles;knk-2 reactor;measuring methods;on-line systems;reactor monitoring systems;sodium
Components Category: Reactor components
display the document: 34086292.pdf
Analysis of reactivity noise observed at KNK-II with respect to vibration of control rods and primary loop components Analyse von Reaktivitaets-Rauschen an KNK-II im Hinblick auf Vibrationen von Absorbern und Primaerkreis-Komponenten
Ansari, S.;Mitzel, F.;Vaeth, WKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.18P65A - German - 1981
Abstract: Various facts indicated that peaks in the Auto Power Spectral Density (APSD) of the neutron flux may be due to vibrations of core components. Possible candidates are the control rods. In order to scrutinize this hypothesis, seismic transducers were mounted on the shrouds of the control rod drive mechanisms of each control rod. Correlation measurements between the signals of these transducers and the neutron flux showed positive results. However from measurements with particular control rods being withdrawn from the core at zero power and from a quantitative analysis of all experimental results it must be concluded that the control rod's vibration do not cause the reactivity noise. Correlations with other signals showed that one peak of the APSD of the neutron flux is probably caused by flow induced vibrations occurring in only one of the two primary coolant loops. A possible explanation of the mechanism which causes the reactivity effects is given
Key words: control elements;control rod drives;correlation functions;knk-2 reactor;mechanical vibrations;reactor control systems;reactor noise;transducers
Components Category: Reactor components
display the document: 34086293.pdf
Avoidance of gas bubble caused scrams at KNK II without reducing the sensitivity of the reactimeter to bulk sodium boiling Vermeidung der an der KNK II durch Gasblasen ausgeloesten Schnellabschaltungen ohne Beeintraechtigung der Sicherheitsfunktion des Reaktimeters bei integralem Natrium-Sieden
Vaeth, WKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.18P67A - German - 1981
Abstract: The KNK II was sometimes tripped by too high negative reactivity which is caused by cover gas passing through the core. Assuming that this gas entrainment is not safety relevant, these scrams may be suppressed. This paper shows, that vibrations of the tank which are observed before a gas bubble passes the core, can be used to avoid the trip: the signal of a seismic transducer triggers a dynamic modification of the reactimeter's threshold value according to a reactivity change which is typical for a gas bubble passage. Thus the reactimeter may still give a prompt trip signal, when a bulk boiling of the sodium in a fuel element occurs. Some statements concerning the reliability of the vibrational signal cannot be given quantitatively before further investigations are done
Key words: boiling detection;cover gas;entrainment;knk-2 reactor;mechanical vibrations;reactivity insertions;reactor cores;reactor safety;scram;transducers
Components Category: -Core components
display the document: 34086294.pdf
Dismantling and post-irradiation examination of the two first defective fuel pins of the KNK-II. Die Zerlegung und Nachuntersuchung des ersten und zweiten defektiven KNK II-Brennelemente
Enderlein, H.;Kathol, W. (Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Hauptabteilung Kerntechnische Betriebe;Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Projekt Schneller Brueter)KFK--3278 - German - 1982
Abstract: The report contained the dismantling and the post irradiation examination of the two first defective fuel elements of the KNK II-reactor. The construction of the dismantling device and the process of dismantling of the fuel elements are described. The main aim of the examination of the fuel pins is to find the defective pin and to establish the cause of the pin damage. The most important steps for this are shown, also a few of the results. Finally improvements to a planned second dismantling device are described. (orig.)
Key words: failed element detection;fuel assemblies;fuel assembly dismantling;fuel element failure;fuel pins;knk-2 reactor;post-irradiation examination
Components Category: --Fuel pins
display the document: 13696679.pdf
Detection of fuel element vibration at KNK II. Nachweis von Brennelementschwingungen in KNK II
Mitzel, F.;Vaeth, W.;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--3379 - German - 1982
Abstract: The reactivity signal of the KNK-II-plant shows almost harmonic oscillations of
Key words: correlation functions;fluid flow;fuel elements;jets;knk-2 reactor;mechanical vibrations;oscillations;reactor noise;vortices
Components Category: --Fuel assemblies
display the document: 14756090.pdf
Vibrational effects of fuel elements detected during KNK II power operation
Mitzel, F.;Vaeth, W.;Ansari, SKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.18P85B - English - 1982
Abstract: The reactivity signal of the KNK II reactor shows almost harmonic reactivity oscillations of
Key words: flow stress;fuel elements;knk-2 reactor;mechanical vibrations;performance testing;reactivity;vortex flow
Components Category: -Core components
display the document: 34086295.pdf
Test operation KNK II: Investigation of the gas entrainments with disengaged reactivity limit (May '81 till Febr. '82) Versuchsbetrieb KNK II: Untersuchung von Gasdurchlaeufen bei abgeschaltetem Reaktivitaetsgrenzwert (Mai '81 bis Febr. '82)
Becker, M.;Richard, H.;Schmidt-Hoenow, MKernkraftwerk-Betriebsgesellschaft mbH (Germany), INTERATOM GmbH Bergisch-Gladbach (DE)
KBG--UP0382.1 - German - 1982
Abstract: During the start-up phase of KNK II the reactor was tripped repeatedly by signals of too negative reactivity, which were caused by gas entrainment. In the frame of a special test program a limited power operation campaign was performed in which the reactivity threshold of the reactimeter was deactivated in order to study the pattern and the amplitudes of the reactivities in the power range of 40 to 90 %. The report describes the course of the test program and its results. All together 22 signals were observed exceeding the threshold of -7.3 cent with a largest peak of -19 cent. An influence of the reactor power could not be observed, but a general difference compared with the operation in 1979/80 could be noted after the mass-flow reduction in the degasification pipe. Probably the discharge mechanism of the gas storage has been changed, but no new knowledge about the storage localization could be gained
Key words: entrainment;gases;knk-2 reactor;power distribution;reactivity;reactor operation;reactor start-up
Components Category: -Core components
display the document: 34087735.pdf
Safety considerations for the KNK II annular fuel element with carbide test bundle Sicherheitsbetrachtungen fuer das KNK II-Ringelement mit Karbidtestbuendel
Haefner, H.EKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.01.02P82B - German - 1982
Abstract: The present safety considerations concern the accident analysis for the KNK II annular fuel element with an integrated 19-pin carbide bundle. In the investigations those possible accidents had been selected from the total number of accidents studied for the first and second KNK II cores, in which the annular element with the carbide bundle could show an irregular behavior. The results of the analysis did not reveal an elevated risk for the irradiation of this special fuel element compared with a standard oxide fuel element
Key words: annular fuel elements;irradiation devices;knk-2 reactor;mixed carbide fuels;reactor safety;reloadable fuel assemblies;replaceable fuel assemblies;risk assessment;safety analysis
Components Category: --Fuel assemblies
display the document: 34087760.pdf
Dynamic simulation of the air-cooled decay heat removal system of the German KNK-II experimental breeder reactor
Schubert, B.KBrookhaven National Lab., Upton, NY (USA)
NUREG/CR--3910 - English - 1984
Abstract: A Dump Heat Exchanger and associated feedback control system models for decay heat removal in the German KNK-II experimental fast breeder reactor are presented. The purpose of the controller is to minimize temperature variations in the circuits and, hence, to prevent thermal shocks in the structures. The basic models for the DHX include the sodium-air thermodynamics and hydraulics, as well as a control system. Valve control models for the primary and intermediate sodium flow regulation during post shutdown conditions are also presented. These models have been interfaced with the SSC-L code. Typical results of sample transients are discussed
Key words: after-heat removal;control systems;feedback;heat exchangers;knk-2 reactor;simulation
Components Category: -Decay heat removal systems
display the document: 16058473.pdf
Final Report about the gas bubble problem in KNK II Abschlussbericht zum Gasblasenproblem der KNK II
Richard, H.;Schade, H.-JKernkraftwerk-Betriebsgesellschaft mbH (Germany), INTERATOM GmbH, Bergisch Gladbach (DE)
KBG--UP1084.2 - German - 1984
Abstract: During the operation of the first core of KNK II repeatedly reactor scrams occurred above a power level of about 60 %, which were initiated by the reactivity limit of -7.3 cent. The scrams were caused by discontinuous gas bubble passages through the core, which lead to peak-like reactivity reductions. In experiments at the plant and in models possible sources of the gas ingress and of gas storages were investigated and identified. As ingress source the degassing line and the primary pumps were identified. The ingress by the degassing line could be eliminated by technical modifications, and the additional ingress via the pumps was found to be so small, that no modifications were performed. The investigations pointed with rather large probability to the annular area besides the grid-plate as the storage of the gas. As solution for the second core of KNK II the flow path towards the reactor core was changed by a modification of the grid-plate inserts. By this means, possible gas quantities are diverted around the core through the reflector assemblies without causing reactivity effects, and the suspected storage in the annular area is eliminated. During the start-up of the second core it was shown, that the gas bubble problem of the first core has been completely eliminated, and this result was fully confirmed by the power operation of KNK II/2
Key words: bubbles;degassing;entrainment;fuel elements;gases;knk-2 reactor;reactivity insertions;reactor cores;reactor operation;scram
Components Category: -Core components
display the document: 34087737.pdf
Temperature transient experiments TETRA in the third core of KNK II Temperaturtransientenexperimente TETRA im dritten Kern des KNK II Reaktors
Reimann, G.;Haefner, H.EKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.01.04P20A - German - 1985
Abstract: Within the development and test of fast breeder fuel elements, several important questions concerning the behavior under transient conditions, under overload and with fuel failures are still open. Focussed on these questions is the experimental program TETRA (Temperature Transient Experiments) foreseen at the KNK II reactor. The experimental equipment contains a measuring and control plug together with the already tested annular fuel elements as carrier element for small test bundles. The plug is fixed on top of the test bundle and allows the variation and measurement of the coolant flow and consequently of the coolant temperature. By this means, a large variety of temperature programs are possible with exact definition and control. Experiments with test bundles of 19 pre-irradiated pins are foreseen, so that on one side the pre-damage as an important parameter for the transient behavior is given, and on the other side there is the feedback within the bundle. The experiments are foreseen in the third core of KNK II. The present report is a preliminary design report for TETRA. In addition to the goals of the experimental program it contains the description of the measuring and control plug, first design and operational data as well as details of handling operations and safety considerations
Key words: annular fuel elements;fluid flow;knk-2 reactor;reactor experimental facilities;reactor safety;reloadable fuel assemblies;replaceable fuel assemblies;safety analysis;temperature coefficient;temperature dependence;testing
Components Category: --Fuel assemblies
display the document: 34087764.pdf
A protocol system as an extension of the MIRA reactor protection system
Elies, V. (Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Datenverarbeitung in der Technik)INIS-mf--10499 - English - 1986
Abstract: At the Karlsruhe Nuclear Research Center the microcomputer-based reactor protection system MIRA is being developed for the KNK II, a 20 MWe experimental LMFBR. The protection system's objective is individual core outlet temperature surveillance and output of a scram signal as soon as a single outlet temperature leaves the defined safety region. Besides it generates warning messages concerning any anomalies within the protection system itself as well as in the reactor core. These messages are issued to a protocol system which provides the operators with detailed informations on the actual state of the protection system and the reactor core. These informations are given as textual messages on operator console and printer and as diagrams on a colour graphics display. The protocol system helps in detecting cooling disturbances at an early stage and it eases the localization of faults within the protection system, thus providing for a quick repair. After a brief description of the MIRA configuration this paper presents the hardware and software structure of the protocol system and the generated outputs. (author)
Key words: computer codes;data processing;electronic equipment;knk-2 reactor;on-line systems;reactor shutdown;safety engineering
Components Category: -Monitoring systems, their circuits and electronics
display the document: 17069159.pdf
Consulting core surveillance system COCOSS I at KNK II
Hoffmann, GKernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Reaktorentwicklung;Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Projekt Schneller Brueter
KFK--4139 - English - 1986
Abstract: Fuel cladding defects cannot be avoided in nuclear power plant operation. In the worst case they may lead to loop contamination or to local cooling disturbance. Especially in case of the liquid metal cooled fast breeder reactor, continuation of plant operation or power set back calls for an expert who possesses comprehensive knowledge of (a) detection and location of failed subassemblies, (b) behavior of failed subassemblies, and (c) questions of safety of the plant while operated with faulty subassemblies. Since such an expert cannot be permanently available, it is intended to transfer this expert knowledge to the COCOSS 'Consulting Core Surveillance System'. This report gives a description of the status of COCOSS as operated at present at KNK II as a measuring data acquisition and evaluation system. In the final stage of implementation COCOSS - inserted in a large diagnosis system - is to make the same calculations for the reactor operator and to give him the same recommendations as he receives now from an expert commanding of an extensive knowledge in this specialized field. (orig.)
Key words: cover gas;flowsheets;fuel cans;fuel element failure;gamma spectra;in pile loops;knk-2 reactor;monitoring;on-line measurement systems;r codes
Components Category: -Monitoring systems, their circuits and electronics
display the document: 18024009.pdf
Safety related investigations for the third core of KNK II with a residence time of 720 equivalent full-power days (part B) Sicherheitstechnische Untersuchungen fuer den dritten Kern der KNK II mit einer Standzeit von 720 Vollasttagen (Teil B)
Becker;Stepan;WinterhagenINTERATOM GmbH, Bergisch-Gladbach (Germany)
IA--70.03907.7 - German - 1986
Abstract: The present report describes safety related investigations for the third core of KNK II with a residence time of 720 equivalent full-power days (efpd). The following aspects have been considered: Decay heat of the core assemblies, core temperatures in case of emergency cooling, primary shielding with shielding of the handling facilities, radioactive materials in the plant and radiological affects on the environment in case of nominal operation and of accidents. In comparison with the second core with its residence time extension to 720 efpd, the results do not show unacceptable changes
Key words: after-heat removal;burnup extension;eccs;fuel cycle;knk-2 reactor;radiology;reactor accidents;safety analysis;shielding;steady-state conditions
Components Category: -Core components
display the document: 34087391.pdf
Operation of KNK with defective fuel assemblies and consequences to be drawn. Presentation at the Exchange Meeting about the operation of KNK II and BOR 60/BR 10 Plants, Dimitrowgrad, September 5.- 8., 1988 Betrieb der KNK mit schadhaften Brennelementen und Konsequenzen daraus. Praesentation auf dem Meeting zum Erfahrungsaustausch ueber den Betrieb von KNK II und BOR 60/BR 10 Anlagen in Dimitrowgrad, 5. - 8. September 1988
Steiger, WKernkraftwerk-Betriebsgesellschaft mbH (Germany)
INIS-DE-KBG--014 - German - 1986
Abstract: The paper illustrates the operational history of KNK II with its first two core loadings with 400 equivalent full-power days (efpd) for the first loading and 455 efpd for the second loading. During this period of 855 efpd eight fuel failures occurred. These failures had been detected by different means, such as radioactivity of the cover gas, delayed neutron detection or the ratio of the Xe131 and Xe134 concentration. The paper explains the type of failures and the lessons learned and consequences drawn from these failures
Key words: failed element detection;failed element monitors;fuel cycle;fuel element failure;isotope ratio;knk-2 reactor;reactor operation;reactor safety;xenon 131;xenon 134
Components Category: -Core components
display the document: 34087484.pdf
Cover gas purification experience at KNK
Richard, H.;Stade, K.Ch. (Kernkraftwerk-Betriebsgesellschaft m.b.H., Eggenstein-Leopoldshafen (Germany));Stamm, H.H. (Institute of Radiochemistry, Nuclear Research Center, Karsruhe (Germany))IWGFR--61 - English - 1987
Abstract: KNK II is an experimental, sodium cooled fast breeder reactor. The reactor was operated until 1974 with a thermal core (KNK I). The plant was converted into a fast breeder reactor (KNK II) from 1974 to 1977. The commissioning of KNK II was started in October 1977 with the first fast core KNK 11/1. After 400 effective full power days (EFPD) the reactor was shut down in August 1982. After replacing the complete core by the second fast core KNK 11/2, the plant went into operation again in August 1983. In August 1986 nearly 400 EFPD were achieved with the second fast core. Argon is used as cover gas in the primary and secondary sodium systems of KNK. In former times fresh argon was supplied by a bundle of gas cylinders. Later on a liquid argon supply was installed. Purification of cover gas is done by flushing only. During KNK I operation no fuel failures occurred. The primary cover gas activity was characterized by the formation of Ar-41, only small quantities of fission gas were measured, released from 'tramp uranium'. Therefore, no problems existed during KNK I operation with regard to radioactive gas disposal. However, after start-up of KNK II, several fuel elements failed. Until August 1986, five fuel failures were observed, two in KNK 11/1, and three in KNK 11/2. Sometimes, operation with defective fuel pins caused problems when fission gases leaked into the containment atmosphere, and the access had to be restricted. The purging rate of the primary cover gas was limited by the capacity of the charcoal filters in the delay line. Of all non-radioactive impurities, hydrogen (Hz) and nitrogen (N2) were of most importance in the primary cover gas. Main source of both impurities was the ingress of air and atmospheric moisture during handling operations in shutdown periods. An other possible source for hydrogen might be a release from the steel-clad zirconium hydride, used as moderator in the moderated driver fuel elements. Additional nitrogen may diffuse through the freeze seals of the primary valves located in the nitrogen-filled 'primary cell' of the plant
Key words: argon;cladding;cover gas;fission products;fuel element failure;hydrogen;knk-2 reactor;nitrogen;primary coolant circuits;purification;reactor protection systems;reactor safety;secondary coolant circuits;sodium;steels;zirconium hydrides
Components Category: -Coolant, cover-gas and Primary cooling system including heat exchangers
display the document: 33011383.pdf
Radiochemical surveillance of KNK primary sodium Radiochemische Ueberwachung des Primaernatriums von KNK
Stamm, H.-H.;Stade, K.ChKernforschungszentrum Karlsruhe GmbH (Germany), Kernkraftwerk-Betriebsgesellschaft mbH (DE)
KFK-PSB--01.02.17P51A - German - 1987
Abstract: Radiochemical surveillance of the KNK primary sodium has been performed now for 15 years with 953 effective full-power days. The overflow method used for sodium sampling proved to be reliable. Different crucible materials have been used for different analytical tasks. The amount of radionuclides in the primary system has not given restrictions to plant operation at any time. On-line gamma spectroscopy on pipings and components of the primary circuits was accomplished in reactor downtimes. Activity depositions on the walls were dominated by Ta-182 after KNK I operation. Main deposited activities at KNK II were Mn-54 (fresh core) and after operation with failed fuel Cs-137, in cover gas areas together with Zn-65. Efficient experimental radionuclide traps for the removal of Mn-54, Zn-65 and Cs-137 from the primary coolant were tested successfully. The dose rates on primary pipes and components of KNK I and KNK II were lower by an order of magnitude compared to water-cooled reactors. This is in good agreement with experiences from LMFBR's in other countries. The resulting average yearly accumulated personal dose rate was 0.21 man-Sv at KNK, compared to 3.9 man-Sv at German light-water-cooled power reactors
Key words: cesium 137;cold traps;deposits;dose rates;gamma spectroscopy;knk reactor;knk-2 reactor;manganese 54;monitoring;primary coolant circuits;radiochemical analysis;radioisotopes;sodium;tantalum 182;zinc 65
Components Category: -Coolant, cover-gas and Primary cooling system including heat exchangers
display the document: 34086284.pdf
Results of tests with open fuel in KNK II Ergebnisse des Einsatzes freier Brennstofftestflaechen in der KNK II
Schmitz, GKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.17P56B - German - 1987
Abstract: For the operation of Liquid Metal Cooled Fast Breeder Reactors with cladding failures the consequences of increased contamination by fission products and fuel and the possibility of failure propagation to adjacent fuel pins due to fuel swelling have to be envisaged. To clarify some of these problems a KNK II test program involving open fuel was defined with the first experiments of this program being performed between October 1981 and May 1984. After the description of the test equipment and of the test program, the results will be presented on delayed neutron measurements, fission gas measurements and post irradiation examinations. The report will conclude with a discussion of the results
Key words: contamination;defects;delayed neutron analysis;failures;fission product release;fuel element failure;knk reactor;knk-2 reactor;testing
Components Category: --Fuel and cladding
display the document: 34086286.pdf
Results of acoustic measurements with an electric boiling generator at KNK II Ergebnisse der akustischen Messungen mit einem elektrischen Siedegenerator in der KNK II
Aberle, JKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.19P16A - German - 1987
Abstract: With regard to an integral core surveillance in sodium-cooled breeder reactors acoustic measurement techniques are under development. To determine experimentally the acoustic transfer function of a reactor core and to demonstrate the detectability of local sodium boiling, experiments with a so-called Boiling Generator were carried out in the KNK II reactor. The main part of this Boiling Generator was an electrically heated pin bundle which was equipped with a local blockage to obtain cooling disturbances. In this report the results of the acoustic measurements carried out with the Boiling Generator are presented. Main topic of the evaluation is the determination of the acoustic transfer function between the core and the upper sodium plenum. The signal conditioning necessary prior to this investigation is also explained. Great effort was required to suppress electrical disturbances which superimposed the acoustic signals and could not be eliminated by the hardware during the experiments. Finally, the detectability of local boiling using acoustic measurements is considered
Key words: acoustic measurements;boiling detection;flow blockage;knk-2 reactor;reactor cooling systems;reactor cores;signal conditioning;sodium;transfer functions
Components Category: -Core components
display the document: 34086296.pdf
KNK II, third core: Safety related investigations (part B) KNK II, dritter Kern: Sicherheitstechnische Untersuchungen (Teil B)
Reetz, AINTERATOM GmbH, Bergisch-Gladbach (Germany)
IA--70.04357.6 - German - 1988
Abstract: The present report describes safety related investigations for the third core of KNK II. The following cases have been considered: reactivity accidents, blockage of a primary pump and simultaneous run-out of the second one, thermal loading of the cooling circuits and local cooling perturbations. The protection targets as they had been defined for the second core, are also reached for the third core. Hereby, a possible drift of the coolant temperatures due to the deposit formation on the fuel pins is admitted to a certain amount. Its tolerable limit is set by the mass flow accident. Since the core configuration, the core surveillance and the process parameters of the circuits of the second and third core are differing only marginally or not at all from each other, the proofs for the stress behavior of the cooling circuits and the damage prevention in case of local cooling perturbations are also almost unchanged. The transitory behavior shows, that the third core is also inherently stable
Key words: coolant loops;flow blockage;knk-2 reactor;loss of flow;reactor accidents;safety analysis
Components Category: -Core components
display the document: 34087394.pdf
First results of the THIBO experiments Erste Ergebnisse der THIBO Experimente
Reiser, H.;Schmidt, L.;Deckers, H.;Lehning, H.;Piel, DKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.01.12P98A - German - 1988
Abstract: It is assumed that the wear damages in the fuel assemblies of the second KNK II core are caused by staggering movements of the fuel pins due to azimuthal temperature differences in the fuel claddings. In order to investigate the conditions for the thermal-hydraulically induced fuel pin oscillations, the THIBO experiments are being performed since November 1987 with an electrically heated test pin in the sodium loop of the IMF III. In this report the test facility of the THIBO experiments is described and first results of two experiments are reported. In these experiments temperature fluctuations have been observed, which indicate periodic pin movements due to temperature changes
Key words: cladding;coolant loops;flow stress;fuel pins;knk-2 reactor;mechanical vibrations;oscillations;temperature dependence;temperature gradients;thermal hydraulics
Components Category: --Fuel assemblies
display the document: 34087769.pdf
Acoustic measurements for boiling detection in the KNK II reactor. Akustische Messungen zur Siededetektion in der KNK II
Aberle, JKernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Reaktorentwicklung;Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Projekt Schneller Brueter
KFK--4580 - German - 1989
Abstract: With regard to an integral core surveillance in sodium-cooled breeder reactors acoustic measurement techniques are under development. To determine experimentally the acoustic transfer function of a reactor core and to demonstrate the detectability of local sodium boiling, experiments with a so-called Boiling Generator were carried out in the KNK II reactor. The main part of this Boiling Generator was an electrically heated pin bundle which was equipped with a local blockage to obtain cooling disturbances. The results of the acoustic measurements carried out with the Boiling Generator are presented. Main topic of the evaluation is the determination of the acoustic transfer function between the core and the upper sodium plenum. The signal conditioning necessary prior to this investigation is also explained. Great effort was required to suppress electrical disturbances that superimposed the acoustic signals and which could not be eliminated by the hardware during the experiments. The boiling noise is compared to static and transient parasitical noise which is to be expected in a reactor. Finally the detectability of local boiling using acoustic measurements is considered. Furthermore the chance to localize the boiling region within the reactor core is discussed on the base of the acoustic boiling signals measured in KNK II. (orig.)
Key words: acoustic monitoring;boiling detection;in core instruments;knk-2 reactor;lmfbr type reactors;reactor monitoring systems;sodium
Components Category: -Monitoring systems, their circuits and electronics
display the document: 20085700.pdf
Investigations of mobility problems of the secondary shutdown unit of KNK Untersuchungen zu den Schwergaengigkeiten der 2. Abschalteinrichtung an der KNK II
Brockmann, K.;Reuter, B.;Schnetgoeke, G.;Zimmermann, EKernkraftwerk-Betriebsgesellschaft mbH (Germany)
KBG--BL89/13.1 - German - 1989
Abstract: During the operation of the second core of KNK II the absorber rods of both shutdown systems showed repeatedly mobility problems, which also caused obligatory reported events. Therefore special investigations were initiated to clarify the reason for these problems, which are described in the present report for the secondary shutdown rods. It was found out that deposits of sodium and its reaction products on the inner surface of the guide tube and on the shielding piston were the origin of the mobility problems due to enlarged friction. Measures to remove these problems are described in the report
Key words: control rod drives;deposition;friction;knk-2 reactor;neutron absorbers;reactor operation;reactor shutdown;scram rods
Components Category: -Protective and shut-down systems (shutdown rods and drive mechanisms, passive control systems, support systems)
display the document: 34087732.pdf
Investigations of mobility problems of the primary shutdown unit of KNK II Untersuchungen zu den Schwergaengigkeiten der 1. Abschalteinrichtung an der KNK II
Brockmann, K.;Reuter, B.;Schnetgoeke, G.;Zimmermann, EKernkraftwerk-Betriebsgesellschaft mbH (Germany)
KBG--BL89/14.1 - German - 1989
Abstract: During the operation of the second core of KNK II the absorber rods of both shutdown systems showed repeatedly mobility problems, which also caused obligatory reported events. Therefore special investigations were initiated to clarify the reason for these problems, which are described in the present report for the primary shutdown rods. It was found out that deposits of sodium and its reaction products on the inner surface of the guide tube and on the shielding piston were the origin of the mobility problems due to enlarged friction. Measures to remove these problems are described in the report
Key words: control rod drives;friction;guide tubes;knk-2 reactor;reactor operation;scram rods;sodium
Components Category: -Protective and shut-down systems (shutdown rods and drive mechanisms, passive control systems, support systems)
display the document: 34087733.pdf
Operating experience with failed fuel elements in the Compact Sodium Cooled Research Reactor KNK II
Steiger, W.O. (Kernkraftwerk-Betriebsgesellschaft mbH, Eggenstein-Leopoldshafen (Germany, F.R.))AECL--9926(v.1) - English - 1990
Abstract: The Compact Sodium Cooled Nuclear Reactor KNK is the only fast breeder research and prototype plant in operation in the Federal Republic of Germany. It is mainly used for the testing of fuel elements, components and different instrumentation devices. This paper gives a comprehensive description of more than 10 years of operating experience with KNK fuel elements. During this time a total number of 8 element failures occurred. The development of failures is reported, their prelocation within the core as well as the identification of the defective items in the fuel handling machine by a hot-dry-sipping procedure. A new time saving method to identify defective elements is introduced. Contamination of the primary loops by the fission product Cs 137 and methods to lower this contamination by installing a cesium trap are discussed. Finally some recommendations are given on how to operate the plant if fuel element failures occur
Key words: cesium 137;failed element detection;fuel element failure;fuel elements;knk-2 reactor
Components Category: --Fuel assemblies
display the document: 22047672.pdf
Background- and simulated leak-noise measurements on ASB-loop, KNK II- and SNR 300-steam generators
Voss, J.;Arnaoutis, N.;Foerster, K.;Moellerfeld, H. (Internationale Atomreaktorbau GmbH (INTERATOM), Bergisch Gladbach (Germany, F.R.))IWGFR--79 - English - 1990
Abstract: During several leak propagation experiments in the ASB sodium loop noise measurements were performed showing the acoustic behaviour of evoluting leaks in a tube bundle section under sodium. Effects like self evolution, secondary leaks and tube ruptures by overheating occurred during these tests and were reflected in the course of acoustic signals. In one of the KNK II steam generators simulated leak noise was detected against background noise throughout the operating power range. Experimental arrangements and results are described. In SNR 300 all of the SGUs are equipped with waveguides and some with accelerometers for background noise measurements. First measurement under isothermal conditions were performed in the past. A gas injection device for acoustic leak simulation is under construction. The design of the experimental acoustic system and first results are presented. (author). 1 ref., 21 figs, 2 tabs
Key words: acoustic monitoring;background noise;experiment planning;knk-2 reactor;leaks;signal-to-noise ratio;simulation;snr reactor;steam generators
Components Category: -Monitoring systems, their circuits and electronics
display the document: 22091454.pdf
Description of the integral calibration test of the KNK II DND system and safety report Beschreibung des integralen Eichtests des KNK II DND-Systems und Sicherheitsbericht
Schmitz, GKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-IRE--5/325/91 - German - 1991
Abstract: Integral calibration of the DND system of KNK II shall be carried out by inserting a fission product source of a U-Ni alloy into the reactor subassembly positions 100 and 511. Fission product release from this source takes place by recoil. Thus, the release rate can be determined. In this report, both the experimental set-up and the test program are described. Furthermore, it shall be demonstrated that the reactor safety is not adversely affected by this experiment
Key words: delayed neutron analysis;fission product release;fuel assemblies;knk-2 reactor;neutron detection;nickel alloys;reactor operation;reactor safety;safety analysis;uranium alloys
Components Category: -Monitoring systems, their circuits and electronics
display the document: 34087747.pdf
Mobility problems at the KNK II shut-down systems, cause investigations and valuation in comparison with the experience at other plants Schwergaengigkeit an den KNK II- Abschalteinrichtungen, Untersuchungen der Ursachen und Bewertung im Vergleich mit den Erfahrungen anderer Anlagen
Hess, BSiemens AG, Bereich Energieerzeugung, KWU (Germany)
KWU-BGL-N--22-92-007 - German - 1992
Abstract: During the operation of the second core of the fast test reactor KNK II the shutdown systems showed repeatedly problems with their mobility, which also caused to be reported events. The present report gives a summary description of the events in chronological order. The investigations to remove the mobility problems and the resulting design modifications are described together with the comments of the licensing authorities on the way to the restart of the plant. The results of the post-irradiation investigations in the hot cells and of sodium-chemical investigations are also described. In addition to the comparison of the events at the KNK plant itself and a review of the experiences at comparable plants it will be shown that all known cases of mobility problems did only influence the availability of the plant but that the safe shut-down of the plant was never at risk
Key words: control elements;control rod drives;friction;knk-2 reactor;reactor control systems;reactor licensing;reactor operation;reactor start-up
Components Category: -Protective and shut-down systems (shutdown rods and drive mechanisms, passive control systems, support systems)
display the document: 34086312.pdf