Accurate real-time monitoring of the reactivity is crucial to guarantee the safe oper-ations of all nuclear reactors. Several standard procedures are well-assessed for the on-line reactivity determination in critical reactor systems. For Accelerator-Driven Systems (ADS) the evaluation of such parameter is still a challenging task in the perspective of the development of such technology and for its scalability up to in-dustrial design. Several research programs (i.e. MUSE, FREY A) have been devoted to estimation of reactivity, testing them against various experiments. In this framework, the research activity performed during the Ph.D. program is focused on the development and assessment of a novel method for on-line reactiv-ity monitoring. The algorithm proposed, once implemented in a numerical tool, has been assessed for both source-free and source-driven systems. Several tests are performed using simulated experiments, (i.e. detector flux signals generated by nu-merical codes) providing promising results. The influence of the statistical noise in the accuracy of the reactivity estimation is investigated in order to prove the adequateness of the method when applied to real experimental detections. The ap-plication of the method to experimental neutron flux measurements has been carried out both critical and subcritical systems. The Boiling Water Reactor (BWR) Tur-bine Trip (TT) Benchmark based on the Turbine Trip test 2 (TT2) in the American Peach Bottom 2 reactor is considered as an interesting test for the method in a typical thermal power reactor. The FREYA (Fast Reactor Experiments for hYbrid Applications) project provided the opportunity to test the method with real data of a source-driven system. The activities of IAEA Collaboration Research Project on Accelerator-Driven Systems (ADS) and Use of Low Enriched Uranium (LEU) in ADS consituted a good framework to apply the technique to further research facil-ities. In particular the collaboration with the Kyoto University Research Institute (KURRI), Japan, gave the possibility to use the method for the interpretation of the experiments involving the Kyoto University Critical Assembly (KUCA).

A new method for reactivity monitoring in nuclear reactors / Nervo, Marta. - (2015).

A new method for reactivity monitoring in nuclear reactors

NERVO, MARTA
2015

Abstract

Accurate real-time monitoring of the reactivity is crucial to guarantee the safe oper-ations of all nuclear reactors. Several standard procedures are well-assessed for the on-line reactivity determination in critical reactor systems. For Accelerator-Driven Systems (ADS) the evaluation of such parameter is still a challenging task in the perspective of the development of such technology and for its scalability up to in-dustrial design. Several research programs (i.e. MUSE, FREY A) have been devoted to estimation of reactivity, testing them against various experiments. In this framework, the research activity performed during the Ph.D. program is focused on the development and assessment of a novel method for on-line reactiv-ity monitoring. The algorithm proposed, once implemented in a numerical tool, has been assessed for both source-free and source-driven systems. Several tests are performed using simulated experiments, (i.e. detector flux signals generated by nu-merical codes) providing promising results. The influence of the statistical noise in the accuracy of the reactivity estimation is investigated in order to prove the adequateness of the method when applied to real experimental detections. The ap-plication of the method to experimental neutron flux measurements has been carried out both critical and subcritical systems. The Boiling Water Reactor (BWR) Tur-bine Trip (TT) Benchmark based on the Turbine Trip test 2 (TT2) in the American Peach Bottom 2 reactor is considered as an interesting test for the method in a typical thermal power reactor. The FREYA (Fast Reactor Experiments for hYbrid Applications) project provided the opportunity to test the method with real data of a source-driven system. The activities of IAEA Collaboration Research Project on Accelerator-Driven Systems (ADS) and Use of Low Enriched Uranium (LEU) in ADS consituted a good framework to apply the technique to further research facil-ities. In particular the collaboration with the Kyoto University Research Institute (KURRI), Japan, gave the possibility to use the method for the interpretation of the experiments involving the Kyoto University Critical Assembly (KUCA).
2015
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2606359
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