1,721,019 research outputs found
Proposed methodology for shielding/activation evaluations in criticai and sub-critical MYRRHA-FASTEF equilibrium configurations
No full textThis work was carried out in the CDT/FASTEF EU FP7 project: it deals with the preliminary core design of MYRRHA-FASTEF, a 100 MW LBE cooled reactor (working in both critical and sub-critical modes) that should be able to demonstrate transmutation and associated technology. The report summarizes the presentation done by the author in the CDT/WP2 meeting on January 18- 20th, 2012, at the SCK-CEN research centre in Mol (B). In such work he showed briefly the proposed methodology for the preliminary shielding/activation analysis for MYRRHA-FASTEF: both the criticai (34.5 wt.% Epu) and sub-critical (30 wt.% Epu) mode have to be investigated by adopting (as a source) the corresponding equilibrium cores. Besides the pysical quantities to be evaluated (prompt and residual doses), the main points/directions of interest are clearly indicated
MYRRHA-FASTEF sub-critical core (30 wt. % EPu): Reactivity coefficients (ERANOS/JEFF3.1) and allowed levalo sub-critically at BoL. Last proposals for the T2.2/D2.2 work plan
No full textThis work was carried out in the COT/FASTEF EU FP7 project: it deals with the prelirninary core design of MYRRHA-FASTEF, a 100 MW LBE cooled reactor (working in both criticai and sub-critical rnodes) that should be able to dernonstrate transrnutation and associated technology. The report surnrnarizes the presentation done by the author in the COT/WP2 rneeting on January 18-20th, 2012, at the SCK-CEN research centre in Moi (B). By working with the 30 wt% Pu (+ 1.65% Am) rnass content in the MOX pellet, the reactivity feedbacks and coefficient of a 58 FA BoL core were investigated by rneans of the ERANOS deterrninistic code. By considering also three main incidental situations, and analysing their effect on the keff value, it resulted possible to establish (at the first glance) the allowed level of sub-criticality at BoL. Finally, the steps of the rernaining T2.2 work plan and the timing of the activities (to be perforrned before the end of the project by the COT T2.2 partners) is indicated
XT-ADS sensitivity analysis
No full textThis work has been carried out in the first period (March-June 2010) In which the author Joined the Central Design Team in Mol (B) for the CDT/FASTEF EU FP7 project. Before to start with the deep characterisation foreseen during the WP2 for FASTEF (100 MW LBE cooled reactor, working in both critical and sub-critical modes), a preliminary code tuning has been carried out by adopting the XT-ADS core layout (developed in IP EUROTRANS, EU FP6 project). The tuning deals with the neutronic codes, in particular: ERANOS (deterministic) and MCNPX (Monte Carlo). The main results have been included in the two SCK-CEN calculation notes here reported. The first calculation note (ANS/RMS/TS/ARTD00CDT-02/827/10-15) highlights the main differences between the ERANOS and MCNPX models for XT-ADS. Then the ERANOS input has been modified to consider the same assumptions adopted by MCNPX. A further tuning of both models yields, as a whole, a reduction of the MCNPX-ERANOS keff difference (at BoL) from by about 2700 pcm down to 1000 pcm. The second calculation note (ANS/RMS/TS/ARTD00CDT-02/827/10-16) summarizes the XT-ADS sensitivity analysis performed by ERANOS ver. 2.1 with two different nuclear data Iibraries: JEFF3.1 and ENDF/BVI.8. The study, carried out by exploiting the basics of standard perturbation theory, points out which nuclides, which cross-section and which range of energy yield the most significant impact on the core reactivity. As in the first note, the ERANOS evaluations (performed in a reference and voided configurations) have been compared with the results obtained with the MCNFX code
MYRRHA-FASTEF sub-critical core (30 wt. % Epu): chosen approach and preliminary ERANOS results. Some proposals for the T2.2/D2.2 work plan
No full textThis work was carried out in the COT/FASTEF EU FP7 project: it deals with the preliminary core design of MYRRHA-FASTEF, a 100 MW LBE cooled reactor (working in both criticai and sub-critical modes) that should be able to demonstrate transmutation and associated technology. The report summarizes the presentation done by the author in the COT/WP2 meeting on October 10-14th, 2011, at the SCK-CEN research centre in Moi (B). By working with the 30 wl. % Pu (+ 1.65% Am) mass content in the MOX pellet, a 58 FA BoL care was proposed and characterised at 80 MW power (550 °C as max clad T) by the ERANOS deterministic code. The main results are almost consinstent with the MCNPX ones (obtained by SCK-CEN): the clad T almost respects its constraint at BoL and during the 90 d sub-cycle. The most significant difference is represented by the keff swing during 90 d of irradiation: 1400 pcm (ERANOS) vs. 1700 pcm (MCNPX). Furthermore, the In-to-Out and Mixed shuffle strategies were investigated in a 540 d fuel cycle. To increase the fuel burn up, 6 steps of 90 d were used (instead of 5 x 90 d used in criticai mode). It results that the correspondent equilibrium cores yield almost the same performances. Nevertheless, to sustain the aimed keff (~ 0.965 / 0.95 at BoC / EoC), the equilibrium care should envisage about 72 FA Finally, the first steps of the remaining T2.2 work pian and the timing of the activities (to be performed before the end of the project by the CDT T2.2 partners) is clearly indicated
Preliminary neutronic and thermal-hydraulic analyses of a fast (LBE cooled) experimental reactor / irradiation facility
No full textThe present report has been carried out within the Euratom collaborative project: 'Central Design Team for a Fast-spectrum Transmutation Experimental Facility (CDT/FASTEF)', inserted in the 7th European Framework Program. Beyond the participation of ENEA as a partner of the project, this work represents the Master Degree Thesis of the author participating to a postgraduate education in nuclear engineering at the university of Bologna (UniBO): 'Master Universitario di II livello in Progettazione e Gestione Sistemi Nucleari Avanzati' (AA 2008/09). The CDT/FASTEF project aims to demonstrate an efficient transmutation of high level wastes and associated technology through a system working in subcritical and/or critical mode: an experimental facility cooled by Lead-Bismuth Eutectic (LBE) is proposed to be designed to an advanced level at the horizon of 2012. In the initial phase of the project, the Work Package n. 1 (WP1) has to provide the 'Definition of specifications and detailed work programme of FASTEF'. In WP1, ENEA has the responsibility of task 1.2, that deals with the 'Analysis of FASTEF to operate in a critical mode'. For this purpose, starting from the XT-ADS (eXperimenTal-ADS) sub-critical core summarily designed during the EUROTRANS Integrated Project (6th EU FP), the present work identifies the main design modifications due to the introduction of the critical operation mode. Beyond neutronic calculations, mainly concerning the introduction of a primary and secondary shutdown systems, a preliminary thermal-hydraulic analysis has been performed in order to assess the flow rate of LBE coolant (and the consequent pressure drop through the core) necessary to respect the technological constraints on fuel and cladding temperatures
Critical core design of MYRRHA-FASTEF: main reactivitycoefficients at BoL, BoC and EoC
No full textThis work was carried out within the framework of the CDT/FASTEF EU FP7 project: it deals with the preliminary core design of MYRRHA-FASTEF, a 100 MW LBE cooled reactor (working in both criticai and sub-critical modes) that should be able to demonstrate transmutation and associated technology. The present neutronic analysis is focused on the criticai option: the main reactivity coefficients were evaluated by means of the ERANOS ver. 2.1 deterministic code. The reference core, with seven centrai In-Pile-Sections (IPS), was defined in CDT-REP007-2011 (reference ENEA Technical Report UTFISSM-P9P0-011). By adopting: the 34.5 wt. % Pu mass content (with 1.65 wt. % of Am in the Pu vector), a 450 days fuel cycle (5 steps of 90 days) and an ln-To-Out shuffle strategy, the core should be criticai at Beginning of Life (BoL) with 57 FA and in the equilibrium sub-cycle with 69 FA (100 MW). Besides the study of the main reactivity coefficients (related to thermal effects) at different time steps of the fuel cycle, other important safety features were investigated as: the anti-reactivity requirements of shutdown systems, the delayed neutron fraction, the void and core compaction effects
Preliminary Evaluation of the ETD I EFIT Neutronic Performances with Deterministic Methods
No full textThis work has been carried out within the framework of the EUROTRANS project. A detailed neutronic analysis of a 300 MWth sub-critical lead cooled reactor, loaded with a large amount of minor actinides and modelled similarly to the 80 MWth LBE PDS-XADS far what concerns the geometrical shape and structural materials, has been performed by means of deterministic methods (with a special procedure .MECONG that makes usa of some ERANOS modules). The fuel isotopic composition, U-free oxide inserted in a MgO matrix (50% volume), has been provided by CEA. Adopting the PDS-XADS fuel cell geometry as reference, the main purpose of this work is to evaluate the influence of the fuel pin diameter (and the corresponding enrichment in Plutonium) on the care performances. In particular, the capability of these systems to burn and transmute minor actinides has been verified by means of burn up calculations (for about five years without refuelling) starting with a sub-criticality level of -3000 pcm far each analysed geometry. Furthermore the main reactivity coefficients, necessary far the dynamic reactor analysis, have been also examined
The current frozen design of the FASTEF critical core (151 SA): ERANOS model based on mechanical drawings (& referred to MCNPX). Some proposals for T2.2/D2.2: definition and simulation of the equilibrium sub-cycle core
No full textThis work was carried out in the CDT/FASTEF EU FP7 project: it deals with the preliminary core design of MYRRHA-FASTEF, a 100 MW LBE cooled reactor (working in both criticai and sub-critical modes) that should be able to demonstrate transmutation and associated technology. The report summarizes the presentation done at the WP2 meeting at the SCK-CEN Headquarters in Brussels on January 19-21, 2011. It describes the current frozen design of the criticai core (68 FA, 151 SA) and its characterisation by the ERANOS 2.1 deterministic code. The accuracy of the model, based on (preliminary) mechanical drawings, was verified by comparing the main results of the analysis with the MCNPX ones supplied by SCK-CEN: the main outcome is the optimal agreement at BoL between deterministic and Monte Carlo methods. Another remarkable result is represented by the definition of the dummy (radial reflector) region: almost two rings in the periphery of the core lattice, which can have different LBE mass flow rates. The structure of the two different kinds of dummy Sub-Assembly (SA) was chosen by looking for a good compromise among the aimed high flux, the fuel enrichment (Pu mass content in MOX) and the level of damage on core barrel. The second part of the presentation defines some details of the WP2/T2.2 work plan for the near future. The main concerns are: - the definition and simulation of the equilibrium sub-cycle core; - some safety criteria related to the requirements of the shutdown systems provided by AREV
Deliverable D4.2 START core conceptual design
No full textThis document reports the main outcomes of the Task 4.2 activities - concerning the “Core design and simulation” defined in the Project Agreement between ENEA and Transmutex (TMX) - and dealing with the neutronic characterization of the “Subcritical Transmutation Accelerated Reactor Technology” (START). Starting from the scoping analyses carried out during the Task 4.1 in which START is operated as “dirty” Pu burner in an open fuel cycle, the main purpose of Task 4.2 was to define a core configuration coping with the sustaining of the evolution of the Mixed Oxide (MOX) fuel from the start-up composition to the equilibrium one, as well as with the general specifications corresponding to the technical feasibility and interface compliance with the rest of the system (e.g., accelerator and spallation modules). By foreseeing START leveraging the ALFRED (Advanced Lead-cooled Fast Reactor European Demonstrator) configuration - i.e., same Fuel Assembly (FA) design, limits and average core temperatures - and considering the technological/design constraints related to the sub-critical core (e.g., 0.975 as maximum allowed sub-criticality level) and accelerator (e.g., 5 mA as maximum proton current) features, the actual fuel cycle capabilities were evaluated for an optimized core with 102 cm fissile length (vs. 81 cm in ALFRED). This deliverable summarizes the main results of the neutronic characterization of the start-up (108 FAs – 250 MW) and equilibrium (132 FAs – 300 MW) cores with the ERANOS code. In a 6-year fuel cycle, the equilibrium core provides a Pu burning rate of 9.9 kg/TWh and an average / maximum burnup of 69 / 100 MWd/kgHM. Additionally, the same core configurations were also used: • to evaluate the burnup performances for a fuel containing the 2.5% of minor actinides in the Pu vector (as at PWRs discharge after 45 GWd/tHM burnup, followed by 12 years for cooling and refabrication): also in this case, the START (accelerator and core) design constraints result to be fully satisfied
Analysis of MYRRHA/FASTEF to operate in a critical mode
No full textThis work was carried out within the Euratom collaborative project: 'Central Design Team for a Fast-spectrum Transmutation Experimental Facility (CDT/FASTEF)' inserted in the 7° EU Framework Program. The project aims to demonstrate an efficient transmutation of high level wastes and associated technology through a system working in subcritical and/or critical mode: the main objective is the advanced design of an irradiation experimental facility cooled by Lead-Bismuth Eutectic (LBE), to be built at SCK-CEN research centre in Mol (B). Starting from the XT-ADS (eXperimenTal-ADS) sub-critical core summarily designed during the IP EUROTRANS project (6° EU FP), this report identifies the main design modifications due to the critical operation mode. Several neutronic calculations were performed by considering the introduction of a primary and a secondary shutdown systems. In the beginning the main XT-ADS features were maintained, as: the FA architecture (with fuel peliet / clad made of MOX 35 wt. % Pu / FMS T91), the core layout and the 8 irradiation positions (foreseen for experimental rigs). The net result of these scoping investigations consists of a couple of sketches for the critical core adapting the XT-ADS FA (analysed in Appendixes B-D). In parallel with these preliminary evaluations, to further increase the fast neutron flux, a detailed study was carried out by assuming different LBE inlet / outiet temperatures and FA / core geometries (Appendixes E-F). This analysis identifies some design modifications able to provide a higher flux by respecting the actual technological constraints. Based on this study and by adopting a different safety approach (that allows more relaxed specifications on the care pressure drop at 100 MW nominal power, par. 3), a reduced pin pitch can be possible (even with a different clad material, 15-15 Ti SS). As a final result, a first sketch of the FASTEF FA and a range of feasible configurations far the critical layout are proposed (par. 5-7). This range takes into account the current lack of information (as: pin diameter, hollow or solid pellet, 30-35 wt. % Epu) and supplies a large data set useful to address the WP2 phase
- …
