An assessment is made of the feasibility of employing spent nuclear fuel elements as a gamma source for the sterilization of sludges generated by industrial and municipal waste-water biological treatment plants. The ORIGEN code is used to determine the strength time pattern of the gamma radiation from the fuel elements of a pressurized water reactor power station with two 1000-MW(electric) reactors when placed in its storage pool Some solutions are suggested for the use of such pools as ponds for the radiotreatment of sludges. Preliminary results show that sufficiently high doses of gamma radiation for the treatment of significantly large quantities of sludge can be obtained. The induced activity is within limits comparable to or less than those occurring naturally in currently used substances.