Controlled air batch-pyrolysis incinerator

Ontario Hydro has operated since 1977 an incineration system for low-level radioactive wastes, located at the Bruce Nuclear Power Development site. The system utilizes a controlled air batch-pyrolysis technique, in which batches of waste are pyrolized in an oxygen deficient atmosphere. Gaseous pyrolysis products are fully oxidized in an afterburner. The original design of the incineration system did not meet the operational requirements in a number of areas: typically, the duration of the burn cycle was much longer than expected, affecting the system's overall waste processing capacity; the off-gas heat exchanger was found to be unsuitable for prolonged service under high temperature cyclic service; the bag filters were blinded frequently; and the primary chamber stainless steel inner liner was permanently deformed after only a few years of operation. Design changes have been carried out throughout the system during its operating life, which stabilized the system's performance. By the end of 1985, the system processed over 1,800 t of radioactive wastes in about 55,000 operating hours, thus becoming one of the most productive incineration systems in the nuclear industry. Further modifications are now underway in an effort to improve the system's waste processing capacity