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Nuclear fuel loading pattern optimisation using a neural network
16
Fuel science
The New Siberian Islands divide the Laptev Sea from the East Siberian Sea. The Archipelago comprises three island groups: De Long Islands, Anjou Islands, and Lyakhov Islands. The regional structural ensemble comprises De Long, Kotel’nyi, Faddeya and Lyakhov tectonic Domains. Aptian-Albian, Late Cretaceous, Palaeocene-Eocene, Oligocene-Miocene, and Pliocene-Eopleistocene tectono-stratigraphic and igneous sequences have been identified on the Islands. The succession of these sequences and their structural and compositional characters provide to distinguish specific stages in the tectonic history of the region showing alteration of regional tectonic environment through the middle Cretaceous and the Tertiary correlative to major North-East Eurasia, Arctic, and Global events. LSl, LS2, and LS3 major regional unconformities have been identified offshore by German geoscientists based on MCS data in the New Siberian Islands area. It is hypothesized in this paper that three offshore sedimentary cover units bounded by the unconformities correlate to the onshore sequences the following way: Unit I comprises Aptian-Albian and late Cretaceous Sequences, Unit II, Palaeocene-Eocene and OligoceneMiocene Sequences, and Unit III comprises Pliocene-Eopleistocene Sequence and overlying Quaternary sediments.
03/01521 Modeling the performance of solar cells with and without the depletion approxlmatlon Abenante.
L. Solar
Energy
Materials
and Solar
Cells, 2002.
73, (2).
and technology (fundamental science, analysis, instrumentation)
the developed methodology. The algorithm was applied to a core considering part of the loading with reprocessed fuels, however this technique can be used for standard loadings.
03/01525 Numerical modeling of seepage-induced sand productlon In oil and gas reservoirs Vaziri, H. H. 36, (l-2),
et al. Journal
of Petroleum
Science and Enginrering,
2002,
71-86.
An elasto-plastic, fully coupled fluid flow and deformation finite element model is proposed for modelling both tensile and shearinduced failure around deep wellbores in oil and gas reservoirs. The problem is of significant interest to the industry as the usual filter measures undertaken (e.g. liners and gravel packs) to prevent solids production (tensile failure) are not only very expensive but also they reduce productivity due to inevitable plugging of the pores in such filters. The impetus for developing the proposed model was to provide the industry with a viable tool to predict the quantity of the produced solids and its concomitant impact on fluid productivity. The proposed model employs a modified form of the Mohr-Coulomb failure envelope along with several numerical algorithms to effectively simulate failure in a numerically accurate and stable form. The model is verified and then applied to a field problem to investigate mechanisms for cavitation-induced productivity enhancement in a multi-layered coalbed methane reservoir.
109%lIh.
The measured internal spectral response and open-circuit voltage of two silicon solar cells were modelled with the simulation program PClD version 4.4 by both applying and not applying the depletion approximation (DA). A comparison between the results from the two modelling approaches shows that dividing the device under exam into regions according to the DA is preferable in order to get both modelling reliability and physical insight into the device operation. Not using the DA leads in fact to both overestimate the bulk lifetime and neglect the optical properties of highly doped regions.
03lOlS22 Models and model uncertainty In the context of risk analysis Nilsen, T. and Aven, T. Reliability Engineering
& System Safety, 2003,
79, (3), 309-317.
This paper addresses the concept of model uncertainty within the context of risk analysis. Though model uncertainty is a topic widely discussed in the risk analysis literature, no consensus seems to exist on its meaning, how it should be measured, or its impact on the application of analysis results in decision processes. The purpose of this paper is to contribute to clarification. The first parts of the paper look into the contents of the two terms ‘model’ and ‘uncertainty’. On this platform it is discussed how focus on model uncertainty merely leads to muddling up the message of the analysis, if risk is interpreted as a true, inherent property of the system, to be estimated in the risk analysis. An alternative approach is to see the models as means for expressing uncertainty regarding the system performance. In this case, it is argued, the term ‘model uncertainty’ loses its meaning.
03/01523 New theoretical approach to the distributed actlvatlon energy model under isothermal conditions and its applications Liu, X. et 01. Ranliao Huaxue Xuebao, 2002, 30, (3),214-217. (In Chinese) The new theoretical elucidation of distributed activation energy model (DAEM) under isothermal conditions was given and the analytic expression of activation energy at the same levets of weight loss from different isothermal weigh loss curves was obtained and the procedures to obtain activation energy curves during whole reaction were proposed. The application of the new theory to isothermal gasification of two Chinese coals showed that the changing activation energy during gasification can describe the process well and its average value agrees with the results from the classical kinetic analysis.
03/01524 Nuclear fuel loading pattern optlmisatlon using a neural network Faria, E. F. and Pereira, C. Amals of‘ Nuclear Energy, 2003, 30, (5), 603-613. An algorithm to optimize the fuel loading pattern (LP) in nuclear reactors was developed using an artificial neural network (ANN) to generate arrangements for the fuel in the core. The core parameters were calculated with the WIMS-D4 and CITATION-LDI2 codes, and the minimization of the maximum power peaking factor (FP,,.) was used to choose the best arrangements. To verify the algorithm a PWR reactor with approximately 113 reprocessed fuel loaded was considered. The neutronic performance of the obtained arrangements and the efficiency of the implemented method were analysed. Several configurations were found for the core presenting better characteristics than the reference configuration adopted, so indicating the viability of
On the thermoeconomical optimization of fin sizing for waste heat recovery
03/01526
Siiylemez, M. S. Emvgy Conversion and ,Mom~gernrnt. 2003. 44, (6), 859.-866. A thermoeconomic optimization analysis is presented yielding simple algebraic formulae for estimating the optimum fin dimensions for energy recovery applications. The PI-PI method is used in the present study, together with the most favourable fin dimensioning criteria. for thermoeconomic analyses of two different fin types. i.e. plate fin and pin fin.
ORWARE - a simulation tool for waste management
03/01527 Eriksson,
0.
et al.
Resources.
Conservation
rend Req~ling,
2002, 36, (4),
287-307.
A simulation model, ORWARE (ORganic WAste REsearch) is described. The model is mainly used as a tool for researchers in environmental systems analysis of waste management. It is a computerbased model for calculation of substance flows, environmental impacts, and costs of waste management. The model covers, despite the name, both organic and inorganic fractions in municipal waste. The model consists of a number of separate submodels, which describes a process in a real waste management system. The submodels may be combined to design a complete waste management system. Based on principles from life cycle assessment the model also comprises compensatory processes for conventional production of, e.g. electricity, district heating and fertilizer. The compensatory system is included in order to fulfil the functional units, i.e. benefits from the waste management that are kept constant in the evaluation of different scenarios. ORWARE generates data on emissions, which are aggregated into different environmental impact categories, e.g. the greenhouse effect, acidification and eutrophication. Throughout the model all physical flows are described by the same variable vector, consisting of up to 50 substances. The extensive vector facilitates a thorough analysis of the results, but involves some difficulties in acquiring relevant data. Scientists have used ORWARE for 8 years in different case studies for model testing and practical application in the society. The aims have been to evaluate waste management plans and to optimize energy recovery from waste.
03/01526 Planar chromatographic separation for the rapid determination of high mass materials In coal derived liquids Islas, C. A. et al. Preprints of qwposia - American Chemical Society, Division of‘Fuel Chemistry. 2002, 47, (2). 647.~648. Preparative thin layer chromatography (TLC) was used to characterized high mass materials from a low temperature coal tar, with pyridine and acetonitrile as liquid phase. The whole tar sample and the single fractions obtained by TLC were examined by size exclusion chromatography and UV-fluorescence spectroscopy. It was demonstrated that TLC provided a rapid and inexpensive fractionation method for the detection of large molecular mass material from tar. The mass balances could not easily be estimated due to the small quantities of involved material, but the samples could be used for a wide range of structural characterization tests.
03/01529 Probability of backflashover In transmission lines due to lightning strokes using Monte-Carlo SlmUlatlOn I. F. et ul. International Journal Svxtems, 2003, 25, (2), 107-l I I.
Gonos,
qf Elrctricol
Fuel and Energy Abstracts
Power & Energy
July 2003
263
Fuel science
The New Siberian Islands divide the Laptev Sea from the East Siberian Sea. The Archipelago comprises three island groups: De Long Islands, Anjou Islands, and Lyakhov Islands. The regional structural ensemble comprises De Long, Kotel’nyi, Faddeya and Lyakhov tectonic Domains. Aptian-Albian, Late Cretaceous, Palaeocene-Eocene, Oligocene-Miocene, and Pliocene-Eopleistocene tectono-stratigraphic and igneous sequences have been identified on the Islands. The succession of these sequences and their structural and compositional characters provide to distinguish specific stages in the tectonic history of the region showing alteration of regional tectonic environment through the middle Cretaceous and the Tertiary correlative to major North-East Eurasia, Arctic, and Global events. LSl, LS2, and LS3 major regional unconformities have been identified offshore by German geoscientists based on MCS data in the New Siberian Islands area. It is hypothesized in this paper that three offshore sedimentary cover units bounded by the unconformities correlate to the onshore sequences the following way: Unit I comprises Aptian-Albian and late Cretaceous Sequences, Unit II, Palaeocene-Eocene and OligoceneMiocene Sequences, and Unit III comprises Pliocene-Eopleistocene Sequence and overlying Quaternary sediments.
03/01521 Modeling the performance of solar cells with and without the depletion approxlmatlon Abenante.
L. Solar
Energy
Materials
and Solar
Cells, 2002.
73, (2).
and technology (fundamental science, analysis, instrumentation)
the developed methodology. The algorithm was applied to a core considering part of the loading with reprocessed fuels, however this technique can be used for standard loadings.
03/01525 Numerical modeling of seepage-induced sand productlon In oil and gas reservoirs Vaziri, H. H. 36, (l-2),
et al. Journal
of Petroleum
Science and Enginrering,
2002,
71-86.
An elasto-plastic, fully coupled fluid flow and deformation finite element model is proposed for modelling both tensile and shearinduced failure around deep wellbores in oil and gas reservoirs. The problem is of significant interest to the industry as the usual filter measures undertaken (e.g. liners and gravel packs) to prevent solids production (tensile failure) are not only very expensive but also they reduce productivity due to inevitable plugging of the pores in such filters. The impetus for developing the proposed model was to provide the industry with a viable tool to predict the quantity of the produced solids and its concomitant impact on fluid productivity. The proposed model employs a modified form of the Mohr-Coulomb failure envelope along with several numerical algorithms to effectively simulate failure in a numerically accurate and stable form. The model is verified and then applied to a field problem to investigate mechanisms for cavitation-induced productivity enhancement in a multi-layered coalbed methane reservoir.
109%lIh.
The measured internal spectral response and open-circuit voltage of two silicon solar cells were modelled with the simulation program PClD version 4.4 by both applying and not applying the depletion approximation (DA). A comparison between the results from the two modelling approaches shows that dividing the device under exam into regions according to the DA is preferable in order to get both modelling reliability and physical insight into the device operation. Not using the DA leads in fact to both overestimate the bulk lifetime and neglect the optical properties of highly doped regions.
03lOlS22 Models and model uncertainty In the context of risk analysis Nilsen, T. and Aven, T. Reliability Engineering
& System Safety, 2003,
79, (3), 309-317.
This paper addresses the concept of model uncertainty within the context of risk analysis. Though model uncertainty is a topic widely discussed in the risk analysis literature, no consensus seems to exist on its meaning, how it should be measured, or its impact on the application of analysis results in decision processes. The purpose of this paper is to contribute to clarification. The first parts of the paper look into the contents of the two terms ‘model’ and ‘uncertainty’. On this platform it is discussed how focus on model uncertainty merely leads to muddling up the message of the analysis, if risk is interpreted as a true, inherent property of the system, to be estimated in the risk analysis. An alternative approach is to see the models as means for expressing uncertainty regarding the system performance. In this case, it is argued, the term ‘model uncertainty’ loses its meaning.
03/01523 New theoretical approach to the distributed actlvatlon energy model under isothermal conditions and its applications Liu, X. et 01. Ranliao Huaxue Xuebao, 2002, 30, (3),214-217. (In Chinese) The new theoretical elucidation of distributed activation energy model (DAEM) under isothermal conditions was given and the analytic expression of activation energy at the same levets of weight loss from different isothermal weigh loss curves was obtained and the procedures to obtain activation energy curves during whole reaction were proposed. The application of the new theory to isothermal gasification of two Chinese coals showed that the changing activation energy during gasification can describe the process well and its average value agrees with the results from the classical kinetic analysis.
03/01524 Nuclear fuel loading pattern optlmisatlon using a neural network Faria, E. F. and Pereira, C. Amals of‘ Nuclear Energy, 2003, 30, (5), 603-613. An algorithm to optimize the fuel loading pattern (LP) in nuclear reactors was developed using an artificial neural network (ANN) to generate arrangements for the fuel in the core. The core parameters were calculated with the WIMS-D4 and CITATION-LDI2 codes, and the minimization of the maximum power peaking factor (FP,,.) was used to choose the best arrangements. To verify the algorithm a PWR reactor with approximately 113 reprocessed fuel loaded was considered. The neutronic performance of the obtained arrangements and the efficiency of the implemented method were analysed. Several configurations were found for the core presenting better characteristics than the reference configuration adopted, so indicating the viability of
On the thermoeconomical optimization of fin sizing for waste heat recovery
03/01526
Siiylemez, M. S. Emvgy Conversion and ,Mom~gernrnt. 2003. 44, (6), 859.-866. A thermoeconomic optimization analysis is presented yielding simple algebraic formulae for estimating the optimum fin dimensions for energy recovery applications. The PI-PI method is used in the present study, together with the most favourable fin dimensioning criteria. for thermoeconomic analyses of two different fin types. i.e. plate fin and pin fin.
ORWARE - a simulation tool for waste management
03/01527 Eriksson,
0.
et al.
Resources.
Conservation
rend Req~ling,
2002, 36, (4),
287-307.
A simulation model, ORWARE (ORganic WAste REsearch) is described. The model is mainly used as a tool for researchers in environmental systems analysis of waste management. It is a computerbased model for calculation of substance flows, environmental impacts, and costs of waste management. The model covers, despite the name, both organic and inorganic fractions in municipal waste. The model consists of a number of separate submodels, which describes a process in a real waste management system. The submodels may be combined to design a complete waste management system. Based on principles from life cycle assessment the model also comprises compensatory processes for conventional production of, e.g. electricity, district heating and fertilizer. The compensatory system is included in order to fulfil the functional units, i.e. benefits from the waste management that are kept constant in the evaluation of different scenarios. ORWARE generates data on emissions, which are aggregated into different environmental impact categories, e.g. the greenhouse effect, acidification and eutrophication. Throughout the model all physical flows are described by the same variable vector, consisting of up to 50 substances. The extensive vector facilitates a thorough analysis of the results, but involves some difficulties in acquiring relevant data. Scientists have used ORWARE for 8 years in different case studies for model testing and practical application in the society. The aims have been to evaluate waste management plans and to optimize energy recovery from waste.
03/01526 Planar chromatographic separation for the rapid determination of high mass materials In coal derived liquids Islas, C. A. et al. Preprints of qwposia - American Chemical Society, Division of‘Fuel Chemistry. 2002, 47, (2). 647.~648. Preparative thin layer chromatography (TLC) was used to characterized high mass materials from a low temperature coal tar, with pyridine and acetonitrile as liquid phase. The whole tar sample and the single fractions obtained by TLC were examined by size exclusion chromatography and UV-fluorescence spectroscopy. It was demonstrated that TLC provided a rapid and inexpensive fractionation method for the detection of large molecular mass material from tar. The mass balances could not easily be estimated due to the small quantities of involved material, but the samples could be used for a wide range of structural characterization tests.
03/01529 Probability of backflashover In transmission lines due to lightning strokes using Monte-Carlo SlmUlatlOn I. F. et ul. International Journal Svxtems, 2003, 25, (2), 107-l I I.
Gonos,
qf Elrctricol
Fuel and Energy Abstracts
Power & Energy
July 2003
263