[en] The device for zero power reactor absolute power measurement is described. The device comprises a neutron flux detector, a current amplifier, a divider and a monitor. With the purpose of expansion of the device functional possibilities a neutron flux second detector, the second current amplifier, the first and the second frequency resonance filters, the first and the second multipliers and an averaging unit are introduced into the device. The device measurement error does not exceed 7%. The measurement time required for detection of the correlated signal component did not exceed 1.5 h