2 edition of evolution of fission gas from overheated UO2 found in the catalog.
evolution of fission gas from overheated UO2
D. A. MacInnes
|Statement||by D.A. MacInnes and J.H. Gittus.|
|Series||SRD -- R358, Safety and Reliability Directorate report -- 358.|
|Contributions||Gittus, J. H., United Kingdom Atomic Energy Authority. Safety and Reliability Directorate.|
|The Physical Object|
|Number of Pages||14|
We present a study of the diffusion of krypton in UO2 using atomic scale calculations combined with diffusion models adapted to the system studied. The migration barriers of the elementary mechanisms for interstitial or vacancy assisted migration are calculated in the DFT+U framework using the nudged elastic band method. The attempt frequencies are obtained from the phonon modes of the defect Cited by: Furthermore, mixing xenon (Xe) fission gas with the helium plenum gas decreases the thermal conductivity of the fuel–cladding gap and can result in fuel overheating. The behaviour of fission gases is thus a key safety issue. For these reasons, the behaviour of fission gases has been the subject of extensive research by both experimental and.
Simulation of fission gas in uranium oxide nuclear fuel Presented at SciDAC-4 PI Meeting, 24 July simulations to understand fission gas and defect behavior. Meso-scale modeling of gas evolution within grains using the Xolotl-fission. The Cluster Dynamics method is assessed for the investigation of fission gas behaviour in a krypton-implanted and annealed UO2 sample. The simulation results are then compared to Thermal Desorption Spectroscopy (TDS) data. A release mechanism is proposed: the initial burst is related to krypton migration via an interstitial mechanism, while the second stage of the release process can be Cited by: 7.
A Physical Description of Fission Product Behavior in Fuels for Advanced Power Reactors ANL/24 by G. Kagana Florida International Univeristy J. Rest Nuclear Engineering Division, Argonne National Laboratory September 4, Cited by: 4. The evaluation of fission gas release from spherical fuel during irradiation testing is critical to understand expected fuel performance under real reactor conditions. Online measurements of krypton and xenon fission products explain coated particle performance and contributions from graphitic matrix materials used in fuel manufacture and Cited by: 2.
Mexico and the law of the sea
Critical issues in environmental management
Soil survey of Limestone County, Texas
Cours Intermediaire De Francais (Student Listening Cassette for Overtures)
dialect of English spoken in Bandon
Address given by Mr Harry Bailey CBE, fraternal delegate from the Co-operative Union.
To kill or cure
Benthic macroinvertebrate studies near the Nickel Plate mine, 1986 & 1987
The Cat, the Fish, and the Fish Tank (Althea First Books)
The Central Business College, Toronto, Ontario
Speed-dependent collision effects on radar back-scattering from the ionosphere
These are incorporated in the SINGAR model developed at SRD in order to analyse fission gas evolution in UO2 undergoing transient heating. The rate controlling process in this model is thermal resolution of gas atoms from intragranular bubbles together with Cited by: 2. Equilibrium fission‐gas release rates from single crystal U02 specimens were studied at temperatures from ° to 13OO°C and with neutron fluxes from 1 × 10 13 to 4 × 10 13 neutrons per cm behavior of the fission‐gas release for different neutron flux levels and temperatures indicates that two processes are by: uo2 molecules for each fission fragment pass ing the uo2 surface corresponded to the num ber found by Rogersfission-gas-release experi ment revealing that the release rate of fission gas in the region of temperature where the rate is temperature-independent could be.
In addition, the release of gaseous fission products from the fuel pellet to the fuel-pellet gap degrades the thermal conductivity of the gap leading to an increase of fuel center temperature, further release of fission gas, and a subsequent increase of the inner pressure exerted on the by: DEVELOPMENT OF THE THEORY OF FISSION GAS BUBBLE EVOLUTION IN IRRADIATED UO 2 FUEL.
Москва Moscow Development of the Theory of Fission Gas Bubble Evolution in Irradiated UO. fission gas bubbles retained in the fuel on grain surfaces and edges can cause radical changes in the fuel microstructure.
These changes in the File Size: KB. Based on both a Halden irradiation test of the micro-cell pellets up to 16 MWd/kgU and experience of fission gas release (FGR) in the conventional UO2 pellet, a simplified approach is proposed to.
The fission inert gases are known to precipitate into bubbles. The growing bubbles cause the fuel to swell.
In addition, fission gas bubbles retained in the fuel on grain surfaces and edges can cause radical changes in the fuel microstructure.
These changes in the fuel microstructure can then result in an enhanced gas release and fuel by: linear relationship between fission gas release from U02 during low temperature (uo2 is estimated to be about.
The behaviour of I, Br and Te is complicated by the fact that these species are most stable as anions in UO2 and UO2-x but as cations in UO2+x.
In our model, Zr and the inert gas species Xe and Kr. Physics-based modelling of fission gas swelling and release in UO2 applied to integral fuel rod analysis Article in Nuclear Engineering and Design –86 March with Reads.
Models for the evolution of fission gas bubble microstructure and release processes have been developed in the past using analytical, and computational,, methods. However, due to the complexity of the microstructures formed during Stage 3, few of these models have attempted to include the effects of triple junction bubbles and the need for a percolated pathway to the surface Cited by: 1.
The fission gas release microscopic model of the mechanistic code MFPR is further developed for modelling of enhanced release from irradiated UO2 fuel under transient conditions of the power ramp.
Kashibe et al. studied experimentally the intragranular gas bubble evolution kinetics during post-irradiation. They found a linear relationship of log 10 N b ∝ log 10 d b, where N b is the bubble density per cubic meter volume and d b is the mean bubble diameter. Here, we should mention that in the simulations, the same initial gas bubble density and similar mean sizes are used as those Cited by: In the development of U0/sub 2/ fuel elements for power reactors, one of the important aspects to be considered is the physical behavior of the fission gas.
The engineering concern is mainly that of pressure build-up inside the sheath, due to the release of fission gas from the oxide. Fission gas signiﬁcantly affects the performance of the fuel matrix under operating conditions, as well as the spent fuel matrix in interim storage or in a geological repository .
In particular, the presence of rare gases in the fuel matrix can lead to the formation of Cited by: E-book or PDF. Fission gas release and fuel rod chemistry related to extended burnup - IAEA.
The evolution of fission gas from overheated UO2 - Nuclear Engineering and Design. In-text: (MacInnes and Gittus, ) Your Bibliography: MacInnes, D.
and Gittus, J., Pellet-clad interaction during transients: The evolution of. Fission gases and helium gas behavior in irradiated mixed oxide fuel pin Article in Journal of Nuclear Materials (1) September with 84 Reads How we measure 'reads'.
Purchase Nuclear Materials for Fission Reactors, Volume 28 - 1st Edition. Print Book & E-Book. ISBNTherefore, fundamental understanding of gas bubble evolution kinetics is essential to predict the thermodynamic property and performance changes of fuels.
In this work, a generic phasefield model was developed to describe the evolution kinetics of intra-granular fission gas bubbles in UO2 fuels under post-irradiation thermal annealing : Li, Yulan.
The influence of microscopic defects in the UO2 crystal structure on fission-gas transport out of grains and release from fuel pellets is described. These defects include point defects such as vacancies, interstitials and fission atoms, and extended defects such as bubbles, pores and dislocations.
point of UO2 was evaluated in terms of pure UO2, UO2 with fission gas (Xe atoms), UO2 with high energy radiation (recoil uranium atom), and UO 2 with fission gas and radiation together.
The dependency of melting on the simulation time was also studied.The evolution of fission products from UO/sub 2/ during irradiation at high temperatures is of primary interest to the Gas-cooled Reactor Project. Fuel tests consisting of UO/sub 2/ pellets encapsulated in Inconel or stainless steel were irradiated in the LITR, ORR, and ETR.
The capsules were pierced in hot cells, and the gases collected in evacuated by: 1.The number of gas atoms knocked on is supposed proportional to the fraction of the fission fragment energy expended in the gas.
If the kinetic energy of a pair of fission fragments were expended entirely in fission gas, the number of atoms knocked on with sufficient energy is set asmore».