| 1. |
- Bécares-Palacios, V., et al.
(författare)
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Reactivity monitoring with imposed beam trips and pulsed mode detectors in the subcritical experiment YALINA-Booster
- 2009
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Ingår i: Proceedings of International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators. - : International Atomic Energy Agency. - 9789201504104
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Konferensbidrag (refereegranskat)abstract
- Reactivity monitoring is one of the urgent problems that require a solution in order to achieve a license for a future full-scale ADS. As a part of the EUROTRANS experiments at the YALINA-Booster facility, presented in this conference, a set of measurements with imposed beam-trips has been performed. Traditionally, the source jerk method has been used in subcritical systems to obtain the reactivity by comparing the total neutron flux before the neutron source removal to the semi-stable delayed neutron flux after the source removal. The deuterium-tritium neutron source of the YALINA-Booster facility can, in addition to pulsed mode operation, operate with continuous beam with short imposed millisecond-scale interruptions, thus providing the possibility to monitor the reactivity at each beam trip in the source jerk manner. In order to test the validity of the beam-trip reactivity values determined by using detectors operating in current-mode (also presented in this conference), the reactivity values of the YALINA-Booster assembly obtained through the beam-trip technique using pulsed-mode detectors is presented in this work. In these experiments, a beam-trip frequency of 1 Hz and an interruption time of ∼20 ms have been chosen and two different core loadings with effective multiplication factor around 0.95 have been investigated. These two different loadings with close to equal reactivity but different source multiplication characteristics make it possible to explore the effect of the different source multiplications. In addition, the response of the imposed beam-trip reactivity monitoring technique to reactivity insertions and removals has been studied through control rod movements. Experimental data from fission chambers have been acquired from all three zones of the core: the fast booster zone, the thermal zone and the reflector.
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| 2. |
- Berglöf, Carl, et al.
(författare)
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Neutron noise measurements in the YALINA-Booster experiments
- 2009
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Ingår i: Proceedings of International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators. - : International Atomic Energy Agency. - 9789201504104
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Konferensbidrag (refereegranskat)abstract
- In addition to the pulsed neutron source measurements and the continuous source beam-trip and current-to-flux measurements performed in the YALINA-Booster facility, also presented in this conference, a set of neutron noise measurements has been performed to achieve a complete characterization of the core. The neutron noise measurements have been performed in three different configurations covering a subcriticality range from 0.85 to 0.977. The Rossi-α neutron noise technique has been applied to detector counts from two channels in the thermal part of the core. The Rossi-α results are compared to the experimental prompt neutron decay constants obtained from the pulsed neutron source measurements. A first approach fitting procedure reveals a need of three exponentials to describe the Rossi-α histograms. It has been found that at deep subcriticality, the fundamental mode decay may coincide with or be close to a higher eigenmode, thus making it difficult to determine the prompt neutron decay constant correctly.
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| 3. |
- Berglöf, Carl, et al.
(författare)
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Pulsed neutron source reference measurements in the subcritical experiment YALINA-Booster
- 2009
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Ingår i: Proceedings of International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators. - : International Atomic Energy Agency. - 9789201504104
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Konferensbidrag (refereegranskat)abstract
- In support of an online reactivity monitoring experiment, also presented in this conference, this work presents the reactivity calibration measurements performed with a pulsed neutron source in the coupled fast-thermal subcritical facility YALINA-Booster. These experiments reveal the complexity of experimentally obtaining a global reactivity from a highly heterogeneous core. Moreover, the effect of varying the source multiplication at constant reactivity on the area ratio technique is explored. It is found that the reactivity obtained with the area ratio technique carry strong spatial dependence, but it can be handled by calculated correction factors. On the other hand the method is showed not to be sensitive to changes in the source multiplication. It is also shown that the prompt neutron decay constant does not vary strongly over the core except at deep subcritical states.
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| 4. |
-
Best Practices for the Knowledge Society. Knowledge, Learning, Development and Technology for All : Second World Summit on the Knowledge Society, WSKS 2009, Chania, Crete, Greece, September 2009. Proceedings
- 2009
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Proceedings (redaktörskap) (refereegranskat)abstract
- This book, in conjunction with the volume LNAI 5736, constitutes the refereed proceedings of the Second World Summit, WSKS 2009, held in Chania, Crete, Greece, in September 2009. The 61 revised full papers presented were carefully reviewed and selected from 256 submissions. The papers deal with information technologies - knowledge management systems - e-business and business, organizational and inter-organizational information systems for the Knowledge Society, knowledge, learning, education, learning technologies and e-learning for the Knowledge Society, social and humanistic computing for the Knowledge Society – emerging technologies for the society and the humanity, culture and cultural heritage - technology for culture management - management of tourism and entertainment - tourism networks in the Knowledge Society, e-government and e-democracy in the Knowledge Society, innovation, sustainable development and strategic management for the Knowledge Society, service science, management, engineering, and technology, intellectual and human capital development in the Knowledge Society, advanced applications for environmental protection and green economy management, future prospects for the Knowledge Society: from foresight studies to projects and public policies, technologies and business models for the creative industries.
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| 5. |
- Fernandez-Ordonez, M., et al.
(författare)
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Reactivity monitoring of a subcritical assembly using beam-trips and current-mode fission chambers : The YALINA-Booster program
- 2009
-
Ingår i: Proceedings of International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators. - : International Atomic Energy Agency. - 9789201504104
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Konferensbidrag (refereegranskat)abstract
- Transmutation of spent nuclear fuel in Accelerator-Driven Systems (ADS) is considered as a key technology for achieving sustainable nuclear energy. In the design of future ADS facilities, the reactivity monitoring system is of highest importance. An extensive experimental program devoted to reactivity monitoring of ADS has been carried out at the subcritical facility YALINA-Booster in the framework of IP-EUROTRANS. The main objective, besides the qualification of the reactivity monitoring techniques, has been to develop electronic chains that can be used in a full power ADS. For this purpose, YALINA-Booster couples a D-T neutron generator to a flexible zero-power subcritical assembly with a coupled fast-thermal neutron spectrum. The high intensity of the accelerator and the possibility to work in continuous or pulsed mode allowed the study of the current-to-flux relationship, beam-trip experiments and dedicated experiments for loading and start-up procedures. In addition, the experimental facility provided the opportunity to test electronic chains in current mode, which correspond to the most probable condition in a full power ADS. The experimental program has mainly been focused on the current-to-flux and beam-trip methodologies using detectors operating either in current or pulsed mode. However, in order to achieve the reference reactivity values of the different loading configurations, an extensive set of measurements based on pulsed neutron source techniques has been carried out. In addition, neutron noise measurements have also been performed. These studies are presented in separated papers within this conference. At present, the experimental campaign has been finished and, for the first time, the reactivity of a subcritical system has been measured within a single instantaneous beam trip (∼20 ms) using fission chambers operating in current mode. The necessary electronic chains to operate the fission chambers in this mode have been developed at CIEMAT. The preliminary results of our analysis show that the reactivity values obtained applying the Sjöstrand method and the slope-fit method using data from current-mode detectors are compatible with those obtained when using standard pulsed-mode detectors (presented also in this conference). The validity of the reactivity determination methods using fission chambers operating in current mode has been stated.
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| 6. |
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Learning and Interacting in the Web : Social networks and social software in the Web 2.0
- 2007. - 4/5
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- Knowledge and learning are social phenomena as well as human-centric. In simple terms, the deployment of emerging technologies in knowledge and learning requires the multilevel support of individuals, teams, communities and networks. The evolution of technologies has made difficult the distinction between the various levels of reference. Put simply, people are not isolated from their micro- or macro-environment. However, technology-supported information highways have developed unforeseen opportunities for knowledge and learning flows between the peers in this network. This paper summarises the Guest Editorial of the Special Issue on Learning and Interacting in the Web: Social Networks and Social Software in the Web 2.0.
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| 7. |
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| 8. |
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| 9. |
- Villamarín, D., et al.
(författare)
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Current-to-flux experimental results in the YALINA-Booster subcritical assembly
- 2009
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Ingår i: Proceedings of International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators. - : International Atomic Energy Agency. - 9789201504104
-
Konferensbidrag (refereegranskat)abstract
- As a part of the IP-EUROTRANS experimental program at YALINA-Booster, presented in this conference, a set of measurements concerning the current-to-flux techniques has been performed. In a subcritical assembly coupled to an accelerator operating in continuous mode, the power of the reactor is related to the accelerator beam current and the external neutron source strength. It is generally assumed that by monitoring the ratio between the accelerator beam current and the neutron source intensity as well as the ratio between the neutron source intensity and the core power, any change in the system can be detected. With this methodology, changes in the system caused by reactivity transients can be isolated. However, it has been observed that this is only true for transients in the time scale of seconds. At CIEMAT, an acquisition system capable of monitoring the core power, the accelerator beam current and the neutron source intensity in the millisecond scale has been developed. It has been observed that, in these short time ranges, the proportionality relationship between these three quantities is not always fulfilled.
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