Annual Inspection of Outfall 10 Diffuser at Dounreay Site

About

Dounreay Site Restoration Limited awarded a contract to Caldive Ltd for the annual inspection of the Outfall 10 Diffuser for four years from 2019 to 2022, with inspections conducted between 1 April and 31 July each year.

The diffuser, located approximately 0.25 nautical miles from the Dounreay Site at a water depth of 25 metres below Chart Datum in a tidal range of 3.5 metres, discharges low-level radioactive liquid effluent.

The scope included an 'as found' visual survey of the diffuser, nine duckbill valves (numbered 4-12), and three blank flanges (numbered 1-3); cleaning marine growth from valves, flanges, chamber interior, and outer parapet; checking duckbills, nuts, and bolts for integrity; inspecting the outer chamber and concrete plinth with particular attention to the south east corner; cleaning all areas as directed; carrying out any required repairs; recording all work on DVD with commentary; and providing a report to DSRL including a description of works, daily dive log, and inspection summary with recommendations.

The contract value was AUD 110,000.