Self‐damage accumulation at 22.5°K has been studied in alpha plutonium enriched and unenriched in238Pu. The enriched specimen was held at this low temperature for a period equivalent to about 14 000 h in terms of damage accumulated in the unenriched specimen. The resistivity of the enriched specimen increased to a maximum of 141.5 &mgr;&OHgr;‐cm and then decreased gradually with additional time. The increase has been attributed to self‐irradiation damage consisting of interstitials and vacancies, and the decrease is discussed in terms of possible effects due to phase transformation, internal stresses, magnetic ordering, impurities, and clustering of defects. Annealing behavior differed widely in the two plutonium specimens studied and this is also discussed.