R&D Category: -Failure and failure propagation mechanisms
8 documents found
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On-line gamma spectroscopy system for observation of the cover gas of KNK II, description and instruction Messplatz on-line Gammaspektroskopie zur Schutzgasueberwachung an der KNK II, Beschreibung und Betriebsanleitung
Hoffmann, G.;Letz, K.DKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.17P02A - German - 1978
Abstract: To get more information about the further evolution of defected fuel pins in the sodium cooled fast reactor KNK II, an on-line measuring system to observe the cover gas activity was developed. A computerized gamma-spectroscope evaluates on-line some significant photo-peaks. The paper describes the hardware and software and gives an instruction manual for this system
Key words: activity levels;cover gas;failed element detection;failed element monitors;gamma spectroscopy;knk-2 reactor;on-line systems;performance testing;reactor safety
Components Category: -Coolant, cover-gas and Primary cooling system including heat exchangers
display the document: 34086277.pdf
Release of fission products from the KNK II fuel element failure and search for released fuel in the primary sodium Freisetzung von Spaltprodukten aus dem KNK II-Brennelementschaden und aktivierungsanalytische Suche nach ausgetragenem Brennstoff im Primaernatrium
Hanke, H.-D.;Clauss, H.;Stamm, H.-HKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.17P24B - German - 1980
Abstract: A first fuel element cladding failure occurred in the KNK II reactor on April 1st, 1979. The activity concentrations of radio nuclides are reported from four sodium samplings: the last sampling before the fuel failure, two samplings with the failed element in the core and one sampling after removal of the failed fuel element. Only I-131, Cs-136 and Cs-137 were released from the failed fuel into the primary sodium. The release fraction of Cs-137 was 5.2 % of a fuel rod inventory. The specific activities of some radio nuclides (Zn-65, Ag-110m, Sb-124,...) in the primary coolant were determined by neutron activation analysis. In addition, efforts were made to find non-radioactive cesium and released fuel in the sodium. The applied procedure is described in detail. Neither in the recent samples nor in Na stock samples from the time before nuclear operation of the plant any cesium or fuel was detected. From detection limits it was concluded, that the Cs content in the 21 metric tons of primary sodium was smaller than 10 mg and the content of fuel smaller than 1.1 mg
Key words: after-heat removal;antimony 124;cesium 136;cesium 137;defects;delayed neutron analysis;fission product release;fuel element failure;iodine 131;knk reactor;knk-2 reactor;neutron activation analysis;neutron detection;primary coolant circuits;silver 110;sodium;testing;zinc 65
Components Category: -Coolant, cover-gas and Primary cooling system including heat exchangers
display the document: 34086281.pdf
KNK II on-line gamma spectrometer: Documentation of measurement results of the defected pin experiments from 28.10.1981 till 22.6.1982 KNK II on-line -Gammaspektrometer: Messwert-Dokumentation der Defektstabexperimente vom 28.10.1981 bis 22.6.1982
Hoffmann, G.;Letz, K.DKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.17P82A - German - 1982
Abstract: From October 28, 1981 till June 22, 1982 three experiments with different artificially defected pins have been performed at KNK II. The paper shows the measured values collected by the on-line gamma spectroscope during these experiments. For comparison, the results of background measurements from July 5 to August 4, 1982 are added
Key words: cover gas;failed element monitors;fuel element failure;fuel pins;gamma spectroscopy;knk-2 reactor;on-line systems;reactor safety;testing
Components Category: --Fuel pins
display the document: 34086287.pdf
Determination of the isotopic ratios Xe131/Xe134 in the cover gas of KNK II (Leaker phase from 6. 4. to 2. 5. 85) Bestimmung der Isotopenverhaeltnisse Xe-131/Xe-134 im Covergas der KNK II (Leakerphase vom 6.4. bis 2.5.85)
Stieglitz, L.;Becker, R.;Will, RKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.17P33A - German - 1985
Abstract: The Institute of Hot Chemistry of the Nuclear Research Center Karlsruhe has developed an experimental method to determine the ratios of noble fission gases in the ppm range with uncertainties of a few percent. This is especially of interest for the Xenon isotopes 131 and 134, the ratio of which is different for U235 and Pu239 fission. For KNK II with the Uranium/Plutonium fuel of the test zone assemblies and the Uranium fuel of the driver zone assemblies, a comparison of measured and calculated ratios could therefore allow to distinguish between a failure in one of the two zones with different fuel type. In this report the experimental method is explained and experimental results are presented for one special fuel failure in KNK II
Key words: delayed neutron analysis;failed element detection;fuel element failure;isotope ratio;knk-2 reactor;plutonium 239;reactor operation;reactor safety;uranium 235;xenon 131;xenon 134
Components Category: -Coolant, cover-gas and Primary cooling system including heat exchangers
display the document: 34086282.pdf
Flux tilting campaign at KNK II on May 3rd, 1985 for the prelocation of a fuel subassembly cladding failure Schieflastbetrieb an der KNK II am 3. Mai 1985 zur Vorlokalisierung eines Brennelement-Huellrohrfehlers
Jacobi, S.;Hoffmann, G.;Jonatzke, O.;Klein, D.;Schleisiek, K.;Schmitz, GKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.02.17P35A - German - 1985
Abstract: This report describes the analysis of the delayed neutron signals before and during the flux tilting campaign to localize the third defected fuel subassembly in KNK II. Including the measurements of the composition of the Xe isotopes, the number of suspect subassemblies could be reduced from 29 to 2. By this way the extent of handling operations for the final location in the fuel handling machine could be reduced drastically. The experience obtained is of importance not only for KNK II and SNR 300, but also in general with respect to the evaluation of alternative location methods less expensive than methods used so far
Key words: delayed neutron analysis;failed element detection;fuel element failure;isotope ratio;knk-2 reactor;neutron flux tilting;neutron flux;reactor fueling;xenon
Components Category: -Monitoring systems, their circuits and electronics
display the document: 34086283.pdf
Fuel pin failures in the second core of KNK II, Experiences and valuation Brennstabschaeden im zweiten Kern der KNK II, Erfahrungen und Bewertung
Kernforschungszentrum Karlsruhe GmbH (Germany), Kernkraftwerk-Betriebsgesellschaft mbH (DE), INTERATOM GmbH, Bergisch Gladbach (DE)IA--75.16997.3 - German - 1987
Abstract: The second core of KNK II has reached until now a residence time of 432 equivalent full-power days (efpd) within the licensed 455 efpd. A license application for a residence time extension to 720 efpd has been supplied. Four fuel assemblies had been unloaded after the occurrence of DND-signals. The post-irradiation examinations of the test assembly NY-308 and of the driver assembly NW-302 showed wear marks on the cladding surface in the area of the upper pin spacer. One fuel pin of the test assembly NY-308 and two fuel pins of the driver assembly NW-302 experienced a cladding failure in the area of maximum interaction with the spacers. The findings show, that the wear marks have a systematic origin, but the failures do occur only stochastically on single pins. It is proved, that no safety related problems for the nominal operation and for accidental situations have to be expected even after 720 efpd. It is ensured, that the plant can be operated within its design and licensing limits
Key words: cladding;delayed neutron analysis;fuel element failure;knk-2 reactor;neutron detection;post-irradiation examination;reactor operation;risk assessment;wear
Components Category: --Fuel pins
display the document: 34087398.pdf
Specialist'meeting on KNK II Failed Fuel Element Experience, Organized by AGT 1. Sumary report Spezialisten Besprechung zu Erfahrungen ueber KNK II Brennelement-Versagen, organisiert von AGT1
Plitz, HKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.11.05P37A - German - 1989
Abstract: Since fuel pin failures cannot be excluded in the coarse of operation of sodium cooled fast reactors, it is necessary to understand mechanisms and evolution of failures as well as the relationship of signal size and failure size, in order to allow and recommend operators to derive operating procedures with element failures in the reactor or in internal storages. For this goal, the organizations of the European collaboration on fast breeder R and D are exchanging their experience with fuel failures. The present meeting is one of the meetings on this issue, on which 9 papers on KNK II fuel failures were presented and discussed. The papers are collected in this report
Key words: defects;failed element detection;fuel element failure;international cooperation;knk-2 reactor;reactor safety;ruptures
Components Category: --Fuel assemblies
display the document: 34086302.pdf
Synthesis Report on the understanding of failed LMFBR fuel element performance Zusammenfassender Bericht zum Verstaendnis des Verhaltens von LMFBR Brennstabfehlern
Plitz, H.;Bagley, K.;Harbourne, BKernforschungszentrum Karlsruhe GmbH (Germany)
KFK-PSB--01.11.05P37B - German - 1990
Abstract: In the coarse of LMFBR operation fuel element failures cannot entirely be avoided as experienced during the operation of PFR, PHENIX and KNK II, where 44 failed fuel elements have been registered between 1978 and 1989. In earlier irradiations, post irradiation examinations showed mixed oxide pin diameter increases up to pin pitch distance, urging to stress reactor safety questions on the potential of fuel pin failure propagation within pin bundles. The chemical interaction of sodium with mixed oxide fuel is regarded to be the key for the understanding of failed fuel behavior. Valuable results on the failed fuel pin behavior during operation were obtained from the SILOE sodium loop test. Based on the bulk of experience with the detection of fuel pin failures, with the continued operation and with the handling of failed pins respectively elements, one can state: 1. All fuel pin failures have been detected securely in time and have been located. 2. Small defects are developing slowly. 3. Even large defects at end-of-life pins resulted in limited fuel loss. 4. Clad failures behave benign in main aspects. 5. The chemical interaction of sodium with mixed oxide is an important factor in the behavior of failed fuel pins, especially at high burnup. 6. Despite different pin designs and different operation conditions, on the basis of 44 failed elements in PFR, PHENIX and KNK II no pin-to-pin propagation was observed and fuel release was rather low, often not detectable. 7. In no case hazard conditions affecting reactor safety have been experienced
Key words: burnup;defects;failures;fast reactors;fuel element failure;fuel-coolant interactions;international cooperation;knk-2 reactor;lmfbr type reactors;performance testing;risk assessment;sodium
Components Category: --Fuel pins
display the document: 34086303.pdf