The self-heating of a plasma by thermonuclear reactions is considered in some detail under the assumption of constant electron density and in the temperature region 4 kev , kT < 20 kev where simple approxiruations yield good solutions to the reaction kinetics. It is concluded that less than approximately 3% T enrichment is unlikely to yield a match-head effect for the D. The slowing down of the charged reaction products and the energy exchange between electrons and ions is considered instantaneous in these calculations. (auth)