Neutron lifetimes and return fraction experimental determinations and analyses in several configurations of the IPEN/MB-01 reactor and its impact in the reactivity system calculation

• Grant number: 13/14908-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2013
• End date: August 31, 2017
• Field of knowledge: Engineering - Nuclear Engineering - Reactor Technologies
• Principal Investigator: Adimir dos Santos
• Grantee: Eduardo Gonnelli
• Host Institution: Instituto de Pesquisas Energéticas e Nucleares (IPEN). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

This work proposes the development of a new methodology for measurement of the reactivity in the IPEN/MB-01 research reactor facility, based on microscopic and macroscopic noise experiments and the Two-Region point kinetic equations model. Differently from the other point kinetic theoretical models, the Two-Region model assumed in this work takes into account the nuclear reactor how a coupled system, which constitute the theoretical basis of all mathematical development, contemplate both regions of the reactor (core and reflector).The study of the reflector effect and its impact in the reactivity is an original fact and, to make possible the viability of this study, the kinetic parameters related to the reflector must be obtained. The main advantage of this new methodology is to obtain the kinetic parameters from the reflector in a purely experimental way, without requiring any secondary parameters, i.e., eliminating all parameters that are difficult to measure or calculate. In this way, Rossi-Alfa and Spectral Densities will be performed in the IPEN/MB-01 facility and, from the Two-Region point kinetic equations model, will be obtained the theoretical expressions for the Auto Power Spectral Densities (APSD) and for the Cross Power Spectral Densities (CPSD), which will be used for least squares fit of the experimental data. The prompt neutron generation time, the neutron lifetimes in the reflector and the neutron return fraction from the reflector to the core will be derived from the fitting and these parameters will be used to calculate the reactivity from the Two-Region Inhour equation.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

GONNELLI, E.; DINIZ, R.; DOS SANTOS, A.; JEREZ, R.; PINTO, L. N.; LANDIM, H. R.; IEEE. A Simple Way to Overcome the Shortage of He-3 Detectors in the IPEN/MB-01 Nuclear Reactor. 2015 4TH INTERNATIONAL CONFERENCE ON ADVANCEMENTS IN NUCLEAR INSTRUMENTATION MEASUREMENT METHODS AND THEIR APPLICATIONS (ANIMMA), v. N/A, p. 4-pg., 2015-01-01. (13/14908-4)

GONNELLI, EDUARDO; DINIZ, RICARDO; PINTO, LETCIA NEGRAO; DOS SANTOS, ADIMIR; IEEE. Characterization of Neutron Detectors at the IPEN/MB-01 Nuclear Reactor. 2017 INTERNATIONAL SEMINAR ON SENSORS, INSTRUMENTATION, MEASUREMENT AND METROLOGY (ISSIMM), v. N/A, p. 5-pg., 2017-01-01. (13/14908-4)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

GONNELLI, Eduardo. Neutron lifetimes and return fraction experimental determination and analyses in several configurations of the IPEN/MB-01 nuclear reactor and its impact in the determination of the reactivity of the system. 2017. Doctoral Thesis - Universidade de São Paulo (USP). Instituto de Pesquisas Energéticas e Nucleares (IPEN/BT) São Paulo.