METHOD FOR EVALUATING EFFECTIVE INTENCITY OF NEUTRON SOURCE IN SHUTDOWN NUCLEAR REACTOR Russian patent published in 2007 - IPC G21C17/104 

FIELD: experimental evaluation of nuclear reactor physical characteristics and estimating its effective multiplication factor and reactivity.

SUBSTANCE: proposed method includes displacement of absorption rods or other disturbance source in reactor core, determination of neutron field response to these displacements by means of neutron detector, and gamma-ray intensity measurements. Effectiveness of neutron source intensity is found from equation Q_ef(t)=k_λλ_d(t), where λ_d(t), is gamma-ray intensity; k_λ is factor found in calibration experiment. This procedure needs no periodic repetition of displacing control rods affording reliable shutdown of reactor. Fission chambers are used as neutron and gamma-ray detectors. Gamma-ray intensity is measured by changing over fission chamber using integral current recording circuit.

EFFECT: enhanced reliability of measurement results, reduced amount of work involving handling of radioactive materials.

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