Neutron noise spectra in nuclear reactors are a convolution of multiple induced reactivities. Under normal IBR-2M reactor operating conditions the full noise range can reach ±22% with respect to average power. Slow changes in average power (induced for instance by the control rods) are thereby much smaller than the neutron noise, however they are of importance in conducting the safe operation of the reactor. The problem we address is the separation of neutron noise from the slow power-changes. For this task we used an algorithm based on the basic element method (BEM) developed at Laboratory of Information Technologies – LIT JINR. The algorithm was applied to both static and dynamic states of the reactor in the 0–2 MW power range. The average processing time for one point on a x86_64 Intel Core i5-4570 Sandy Bridge processor at 3.20 GHz, was approximately 50 μs, which allows the use of the MSPPA-6 algorithm in real time.