Numerical calculation of the global and local components of the neutron noise field in boiling water reactors

A numerical model of the neutron noise field in boiling water reactors (BWRs), which can be readily implemented in existing deterministic computer codes, was formulated. The basis of the model is the assumption of separability of the noise field into local and global components. The application of this modeling was twofold: to determine the frequency range above which cross-correlation techniques can be used to measure steam velocities under normal operating conditions and to evaluate the validity of the point kinetics description of the global component of the neutron noise in BWRs. This paper describes a method for the calculation of the ratio of the local to the global components of the neutron noise field. 17 refs