Control of detonative cleaning apparatus

An apparatus is provided for cleaning one or more surfaces within a vessel (200) having a vessel wall separating a vessel exterior from a vessel interior and having a wall aperture. The apparatus has at least one elongate conduit (202) having an upstream first end and a downstream second end and positioned to direct a shockwave from the second end into the vessel interior. A source of fuel and oxidizer is coupled to the conduit (200) to deliver the fuel and oxidizer to the conduit. An initiator is positioned to initiate a reaction of the fuel and oxidizer to produce the shockwave. At least one sensor (206,207,208) coupled to the conduit (202) to detect motion indicative of a detonation. A control system coupled to the initiator, the source, and the sensor (206,207,208) for receiving input from the sensor and controlling operation of the initiator and source responsive to said input.