Year
2006
Abstract
This project is a proposal to use an anti-neutrino detector to monitor nuclear reactor activity, including fuel handling. It will be placed outside of the reactor building, giving independent information concerning the reactor operations in a non-intrusive way. This technique, as an application on safeguards verification, will be used at the Brazilian Angra II reactor, with 4 GW of thermal power corresponding to an anti-neutrino flux intense enough to generate ~ 103 events per day in a detector of one ton scale, placed at 60m from the reactor core. The first tests will be done in a stainless steel tank (1.0 x 1.0 x 1.5 m3) filled with gadolinium doped liquid scintillator. Light from neutrino interactions (inverse-ß decays) is collected by three photomultipliers placed in the tank upper wall. Time and charge of photomultiplier pulses are processed by front-end electronics and data acquisition system controlled by a PC. We intend, in a first step, to use the measured neutrino event rate to monitor the thermal power delivered by the reactor with 1% accuracy. In a second step of the experimental program, we intend to improve the detector design based on first phase results and determine the fuel isotopic composition through a precise neutrino energy spectrum measurement, which is affected by the burn-up effect. The project, managed by an international scientific collaboration (Brazilian, European and American researchers), has already got support from Eletronuclear, the operator of the nuclear plant, and the Brazilian government regulatory agency for the nuclear area. The detector performance and results will be followed up by ABACC – Brazilian-Argentinean Agency for Control and Inventory of Nuclear Material, and the IAEA – International Atomic Energy Agency will be invited to assess the potential of the technology. In addition to the safeguards issues the project can result, to the nuclear operator, in an alternative tool to have an independent control of the delivered thermal power. Regarding aspects of fundamental physics, this project is also part of a long term experimental program aiming to measure Theta-13, one of the unknown neutrino mixing parameters and crucial to further progress of elementary particle physics.