METHOD FOR DETERMINING FLUENCE OF FAST NEUTRONS IN TYPE VVER-1000 REACTOR Russian patent published in 2004 - IPC

FIELD: nuclear reactor physics and engineering.

SUBSTANCE: proposed method meant for metering fluence of fast neutrons at energy over 0.5 MeV using check test pieces made of vessel material of water-moderated water-cooled reactor VVER-1000 includes installation of mentioned check test pieces near vessel above reactor core, holding of check test pierces in running reactor, extraction of check test pieces, measurement of irradiated material characteristics, and determination of fast neutron fluence; in the process crystal lattice of diamond in adding diamond sensor is checked for increase in its volume, and fast neutron fluence is found from formula F = 57.0 x ln [1 - 0.417(ΔV/V)], where F is fast neutron fluence x 10¹⁸, cm^-2 at E > 0. MeV; -57.0 is factor, cm^-2; V is diamond crystal lattice volume, 10^-24 cm³; ΔV is post-irradiation increase in volume of diamond crystal lattice, 10^-24 cm³; ΔV/V is relative expansion of diamond crystal lattice, %.

EFFECT: enhanced reliability of fluence determination at long irradiation periods; reduced labor consumption.

1 cl, 3 dwg, 1 tbl