All staff at the Dounreay nuclear energy complex will get a free wind-up radio if there are no security breaches at the Caithness site for 60 days.
The challenge is laid down in the in-house magazine, Dounreay News, and started on Monday.
It is being run to raise awareness about security procedures and regulations.
Thousands of workers are involved in a massive, long-running decommissioning of the experimental nuclear power site.