Measurement of Excess Heat and Apparent Coincident Increases in the Neutron and Gamma-Ray Count Rates During the Electrolysis of Heavy Water

Excess heat and apparent increases in the neutron and gamma-ray count rates have been observed in a series of tests performed at Oak Ridge National Laboratory to study the electrolysis of heavy water in the presence of palladium cathodes. For these tests, LiOD at a concentration of 0.1 to 1 N in D₂O was used in an insulated glass electrochemical cell in which the temperature was controlled and heat was removed by flowing water in a cooling jacket. Results of two of the tests, one of which lasted for over 1900 h, are reported. In the latter test, an internal D₂-O₂ recombiner was incorporated into the cell to give a closed system without off-gas. Excess power, usually in the range of 5 to 10%, was detected for periods of many hours. Some of these events were initiated and could be extended by system perturbations. On three separate occasions, the mean neutron count rate exceeded the background by statistically significant values; one of these was apparently coincident with an extended period of excess heat generation. Increases in the gamma-ray count rates were apparently also coincident with two of the periods of excess neutrons.