Tritium Generation in Palladium Cathodes with High Deuterium Loading

Tritium up to fifty times background has been observed upon electrolyzing 1N D2SO4 in four out of four cells when using Pd cathodes "of a certain type". No tritium was detected in four control cells, containing H2S04 in H2O, employing Pd cathodes cut from the same wire spool. Tritium amounts were from 7 x 10 to 2.1 × 10 atoms, corresponding to average generation rates from 5.1 × 10 to 2 × 10 atoms/sec/cm. In all cases, D/Pd and H/Pd loadings of 1 ± 0.05 were attained. A cyclic loading/unloading regime rather than the usual continuous constant current regime was applied to attain these high loadings. Tritium analysis was performed in Pd, electrolyte and the gas head space of the sealed cells. Maximum tritium concentrations of 8.9 × 10 atoms/g Pd, 180 times the detection limit, were found in the D-loaded Pd cathodes, none in the Η-loaded Pd, Also, no tritium within detection limit was found in 150 unused Pd pieces. Of these, 13 were cut randomly from the same wire spool as the four D-loaded Pd cathodes. The probability that the tritium in the latter was due to random spot contamination is computed as 1 in 2,380. It is concluded that the tritium was generated by nuclear reactions in the Pd. However, no tritium was detected in four D-loaded Pd cathodes of a different type in spite of attaining loadings D/Pd = 1. Different metallurgical history and impurity contents may play an important role.