A laser-fluorescence system is developed that uses a He-Ne (633 nm) la
ser for continuous monitoring of I-129 during HNO3 dissolution of irra
diated nuclear fuel. Tests at Khlopin Radium Institute indicated that
the sensitivity of the I-129 detection (at worst 8.10(-5) g/m(3)) ensu
res reliable monitoring of this isotope both directly in the working g
as during industrial reprocessing of irradiated nuclear fuel and follo
wing gas-purification systems at radiochemical plants.