Auto-correlation and variance-to-mean measurements in a subcritical core obeying multiple alpha-modes
2011 (English)In: Annals of Nuclear Energy, ISSN 0306-4549, E-ISSN 1873-2100, Vol. 38, no 2-3, 194-202 p.Article in journal (Refereed) Published
Neutron noise measurements based on the Rossi-alpha and Feynman-alpha methodologies have been performed in a heterogeneous subcritical system. It is shown that the traditional single alpha-mode formulations of the Rossi-alpha and Feynman-alpha methods are not applicable due to the presence of higher alpha-modes. Formalisms taking into account multiple alpha-modes are applied resulting in satisfactory results. Three alpha-modes could be identified using the Rossi-alpha method, whereas only two could be obtained using the Feynman-alpha method. In the Feynman-alpha case, the possibility to obtain the fastest decaying alpha-mode was diminished due to detector dead time effects. It was found that the slowest decaying alpha-mode does not exactly correspond to the prompt decay found in pulsed neutron source measurements, which confirms the results of previous studies. Strengths and weaknesses of the multiple alpha-mode Rossi-alpha and Feynman-alpha methods observed in this study are pointed out.
Place, publisher, year, edition, pages
2011. Vol. 38, no 2-3, 194-202 p.
Neutron noise experiment, Auto-correlation, Rossi-alpha, Variance-to-mean, Feynman-alpha, Reactivity determination
IdentifiersURN: urn:nbn:se:kth:diva-13583DOI: 10.1016/j.anucene.2010.11.009ISI: 000287571100004ScopusID: 2-s2.0-78751615182OAI: oai:DiVA.org:kth-13583DiVA: diva2:326029
QC 20100621 Uppdaterad från submitted till published (20110315).2010-06-212010-06-212011-03-15Bibliographically approved