METHOD OF DETERMINING STEAM COEFFICIENT OF REACTIVITY Russian patent published in 2012 - IPC G21C17/00 

FIELD: physics.

SUBSTANCE: method of determining steam coefficient of reactivity (SCR) on a nuclear power plant with high-power channel-type reactors, involving measuring fast power coefficient of reactivity (FPCR) when "weighing" the section of the nuclear reactor rods. There is no perturbation on coolant density through significant change to RPV, carried out remotely by valves of feed units when switching from standard automatic mode to remote (manual) control of the level in the BS; there is also no complex thermohydraulic calculation the change in steam content and FPCR measurements are directly used to obtain a SCR estimate corresponding to the axial profile of change in steam content as a result of perturbation of the reactor power and SCR is determined from the FPCR measurement results based on use of a structural relationship which links these parameters where α_T is the fuel temperature coefficient of reactivity; α_φ ^w is the SCR value which corresponds to the axial profile of change of steam content as a result of perturbation of reactor power, from the formula taking into account constancy of the Doppler content of FPCR (αT∂T/∂W), equal to 3.3·10^-4 β/MW.

EFFECT: invention increases reliability and safety of using reactor units.

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