Determination of the long-lived ~(10)Be in construction materials of nuclear power plants using photoactivation method

摘要

The problem of handling nuclear power plant irradiated structural materials holds one of the central places in the nuclear power industry. High toxic Be-10 with a half-life of T-1/2 = 1.6 x 10(6) years is discovered in NPP structural materials after reactor operating. Be-10 decays through only electrons' emission. Pure beta emitters are extremely difficult to determine in irradiated structural materials and radioactive waste. We proposed a photoactivation approach for determining the Be-10 activity in NPP samples. The proposed method involves determining Be-9 and B-10 concentrations and subsequent recalculation of Be-10 activity formed in Be-9(n,gamma)Be-10 and B-10(n, p)Be-10 reactions. The amount of Be-9 and B-10 is determined by samples' photoactivation using an electron accelerator and Be-9(gamma, 2n)Be-7-, B-10(gamma, p2n)Be-7-reactions. These reactions' experimental yields were measured for 20, 40, and 55 MeV boundary energies of the bremsstrahlung beam. The proposed technique was tested on samples of ChNPP 2nd unit irradiated structural materials. The technique's calculated error is about 15-20%; the sensitivity is 1 Bq x g(-1).