The GUINEVERE Project for Accelerator Driven System Physics

paper 9414International audienceThe GUINEVERE project is part of the EUROTRANS Integrated Project of the 6th EURATOM Framework Programme. It is mainly devoted to ADS on-line reactivity monitoring validation, sub-criticality determination and operational procedures (loading, start-up, shut-down, ...) as a follow-up of the MUSE experiments. The project consists in coupling a fast lead core, set-up in the VENUS reactor at SCK*CEN Mol (B), with a GENEPI neutron source under construction by CNRS. To accommodate the accelerator in a vertical coupling configuration, the VENUS building is being heightened. The fast core will be loaded with enriched Uranium and will be moderated and reflected with solid lead (zero power experiment). For the purpose of the experimental programme, the neutron source has to be operated not only in pulsed mode but also in continuous mode to investigate the current-to-flux reactivity indicator in representative conditions of a powerful ADS. In this latter mode it is also required to make short beam interruptions to have access to the neutron population decrease as a function of time: from this spectrum it will be possible to apply different analysis techniques such as "prompt decay" fitting techniques and "source jerk" techniques. Beam interruptions will be repeated at a programmable frequency to improve time spectra statistics. Different sub-criticality levels (keff=0.99, 0.97, 0.95, ...) will be investigated in order to obtain a full set of data points for the final overall validation of the methodology. This paper describes the status of the experimental facility assembling, and the foreseen experimental programme to be started

The GUINEVERE project at the VENUS facility

Proc. on CD Rom log315International audienceThe GUINEVERE project is an international project in the framework of IP-EUROTRANS, the FP6 program which aims at addressing the main issues for ADS development in the framework of partitioning and transmutation for nuclear waste volume and radiotoxicity reduction. The GUINEVERE project is carried out in the context of domain 2 of IP-EUROTRANS, ECATS, devoted to specific experiments for the coupling of an accelerator, a target and a subcritical core. These experiments should provide an answer to the questions of online reactivity monitoring, sub-criticality determination and operational procedures (loading, start-up, shutdown, …) in an ADS by 2009-2010. The project has the objective to couple a fast lead core, within the VENUS building operated by the SCK•CEN, with a neutron generator able to work in three different modes: pulsed, continuous and continuous with beam interruptions at the millisecond scale. In order to achieve this goal, the VENUS facility has to be adapted and a modified GENEPI-3C accelerator has to be designed and constructed. The paper describes the main modifications to the reactor core and facility and to the accelerator, which will be executed during the years 2008 and 2009, and the experimental programme which will start in 2009

Towards reduction of Paradigm coordination models

The coordination modelling language Paradigm addresses collaboration between components in terms of dynamic constraints. Within a Paradigm model, component dynamics are consistently specified at a detailed and a global level of abstraction. To enable automated verification of Paradigm models, a translation of Paradigm into process algebra has been defined in previous work. In this paper we investigate, guided by a client-server example, reduction of Paradigm models based on a notion of global inertness. Representation of Paradigm models as process algebraic specifications helps to establish a property-preserving equivalence relation between the original and the reduced Paradigm model. Experiments indicate that in this way larger Paradigm models can be analyzed.Comment: In Proceedings PACO 2011, arXiv:1108.145

Postoperative complications after procedure for prolapsed hemorrhoids (PPH) and stapled transanal rectal resection (STARR) procedures

Procedure for prolapsing hemorrhoids (PPH) and stapled transanal rectal resection for obstructed defecation (STARR) carry low postoperative pain, but may be followed by unusual and severe postoperative complications. This review deals with the pathogenesis, prevention and treatment of adverse events that may occasionally be life threatening. PPH and STARR carry the expected morbidity following anorectal surgery, such as bleeding, strictures and fecal incontinence. Complications that are particular to these stapled procedures are rectovaginal fistula, chronic proctalgia, total rectal obliteration, rectal wall hematoma and perforation with pelvic sepsis often requiring a diverting stoma. A higher complication rate and worse results are expected after PPH for fourth-degree piles. Enterocele and anismus are contraindications to PPH and STARR and both operations should be used with caution in patients with weak sphincters. In conclusion, complications after PPH and STARR are not infrequent and may be difficult to manage. However, if performed in selected cases by skilled specialists aware of the risks and associated diseases, some complications may be prevented

La relation entre la vitesse critique de refroidissement et le diagramme de phases dans le système B2O3-Na2O

As a decisive factor in the formation of a glassy phase from a silicate or borate melt on cooling, the crit. rate of cooling (vcr) was studied for the system Na2O 0-50 mole-B2O3 by the systematic measurement of the cooling rate conditions controlling crystn. from the melt on cooling, or from glass by heating. The WELCH thermocouple heating device (cf. Gossink, 1970) was used by which the beginning of crystn. during cooling and heating could be obsd., and thus the vcr was calcd. for 1 mg samples. The log of vcr as a function of the Na2O concn. in the binary mixts. coincides when plotted on the temp.-mole fraction projection of the phase diagram with the max. of congruent fusion-crystn. equil. for the stoichiometric ratios Na2O:B2O3 = 1:1; 1:2; 1:4; the min. of the log vcr curve coincided with the compn. of binary eutectica with 30 and 34 mole Na2O. There is a min. for the peritectic equil. for the 1:3 compn. The temp. of the first indication of crystn. in the melt on cooling (Tcm), and in the glass on heating (Tcg) were detd. at a rate of +-1 Deg/sec. The interval between Tcm and Tcg indicates the presence of easily crystallizing compns., and crit. temp. ranges which must be passed as rapidly as possible to avoid devitrificatio

La relation entre la vitesse critique de refroidissement et le diagramme de phases dans le système B2O3-Na2O

As a decisive factor in the formation of a glassy phase from a silicate or borate melt on cooling, the crit. rate of cooling (vcr) was studied for the system Na2O 0-50 mole-B2O3 by the systematic measurement of the cooling rate conditions controlling crystn. from the melt on cooling, or from glass by heating. The WELCH thermocouple heating device (cf. Gossink, 1970) was used by which the beginning of crystn. during cooling and heating could be obsd., and thus the vcr was calcd. for 1 mg samples. The log of vcr as a function of the Na2O concn. in the binary mixts. coincides when plotted on the temp.-mole fraction projection of the phase diagram with the max. of congruent fusion-crystn. equil. for the stoichiometric ratios Na2O:B2O3 = 1:1; 1:2; 1:4; the min. of the log vcr curve coincided with the compn. of binary eutectica with 30 and 34 mole Na2O. There is a min. for the peritectic equil. for the 1:3 compn. The temp. of the first indication of crystn. in the melt on cooling (Tcm), and in the glass on heating (Tcg) were detd. at a rate of +-1 Deg/sec. The interval between Tcm and Tcg indicates the presence of easily crystallizing compns., and crit. temp. ranges which must be passed as rapidly as possible to avoid devitrificatio

Supervisory control theory toegepast op pretparkvoertuigen

Supervisory control synthesis maakt het mogelijk om besturingen automatisch af te leiden. Aan de hand van een casestudy over pretparkvoertuigen evalueren Jos Baeten en Asia van de Mortel-Fronczak de toepasbaarheid van recent ontwikkelde technieken op dit gebied en de integratie ervan in een systeemontwikkeltraject. De gesynthetiseerde besturing is succesvol geïmplementeerd en geïntegreerd in het bestaande platform

Integration of supervisory control synthesis in model-based systems engineering

Due to increasing system complexity, time-to-market and development costs reduction, there are higher demands on engineering processes. Model-based engineering can play a role here because it supports system development by enabling the use of various model-based analysis techniques and tools. As a result, they are able to cope with complexity and have the potential to reduce time-to-market and development costs. Moreover, supervisory control synthesis can be integrated in this setting, which can contribute to the development of control systems. This paper gives an overview of recently developed supervisor synthesis techniques and tools. To evaluate the applicability of these techniques and to show how they can be integrated in an engineering process, a few industrial cases are discussed. The supervisors synthesized for these cases have successfully been implemented and integrated in the existing resource-control platform