  Using data assimilation framework, to merge information from model and
measurement, an optimal reconstruction of the neutronic activity field can be
determined for a nuclear reactor core. In this paper, we focus on solving the
inverse problem of determining an optimal repartition of the measuring
instruments within the core, to get the best possible results from the data
assimilation reconstruction procedure. The position optimisation is realised
using Simulated Annealing algorithm, based on the Metropolis-Hastings one.
Moreover, in order to address the optimisation computing challenge, algebraic
improvements of data assimilation have been developed and are presented here.
