High accuracy tritium measurement for the verification of the tritium production rate calculations with MCNPX

This paper presents high accuracy tritium production rate measurement results compared with calculations using the MCNPX Monte Carlo particle transport code. The experimental results are regarded as reference values for a new passive technique based on the secondary charged particle activation method developed for measuring the tritium production rate in the test blanket modules of the ITER Tokamak. The 16O(t,n)18F reaction, which is one of the possible tritium monitor reactions, was also extensively investigated, and the experimentally determined reaction rates were compared with simulations.Li2CO3 solution was filled and sealed into quartz ampoules which were irradiated in the Training Reactor of the Budapest University of Technology and Economics. The amount of 18F was determined using γ-spectroscopyγ-spectroscopy. Then the precise tritium measurements were carried out in the Hertelendi Laboratory of Environmental Studies using the 3H–3He ingrowth method, where the 3He produced during the storage time is measured by a static noble gas mass spectrometer (VG-5400).The HT/HTO ratio in the irradiated aqueous solutions was found to be 0.1323±0.00340.1323±0.0034. Based on the comparison of the measurements and the simulations it was pointed out that the model calculations underestimate the reaction rate of both the Li6(n,t)α and the 16O(t,n)18F reactions by 5–10% and 15%, respectively.

► Tritium measurements for verifying the 6Li6(n, t)α reaction rate calculated by MCNPX.
► The HT/HTO ratio was determined in the neutron irradiated aqueous solution of Li2CO3.
► The reaction rate of 16O(t,n)18F was measured in thermal neutron spectrum.