The Nuclear Decommissioning Authority

 

Dounreay is well on its way to destroying the largest single hazard left over from the fast reactor research and development programme.

The equivalent of approximately 5,000 litre bottles of the liquid metal coolant sodium-potassium (NaK) has been safely removed, treated and destroyed. 

The coolant liquid represents a large percentage of the site's total hazard and its removal means that, pending regulatory approval, the plant can start operating at full capacity.

The safe destruction of the 30 batches from the coolant system of the Dounreay Fast Reactor was completed a month ahead of schedule, thanks to the hard work of all involved.

Removal of the radiologically contaminated NaK from the primary circuit is a crucial part of the site decommissioning programme being undertaken on behalf of the Nuclear Decommissioning Authority.

The highly reactive NaK was safely dissolved in a revolutionary plant, designed over a period of more than 20 years, and transformed into sodium/potassium nitrate, which can be dealt with as intermediate-level waste, and salt water. The NaK is heavily contaminated with radioactive caesium and is a chemical and radioactive hazard which reacts violently with air and instantly with water.

Mike Brown, the reactor's decommissioning unit manager, said:

"The DFR NaK is the second-highest hazard for the entire NDA estate and it's critical we meet the necessary safety and environmental standards.

"The removal of the NaK has presented unique challenges over a considerable time and the safe removal and treatment of this highly dangerous material is a huge step towards completing one of the major decommissioning milestones the site has to manage. DSRL and its contractors are extremely committed to this project which is a complex and problematic legacy from the past."