There'll be further strike action at Sellafield in the coming days.
This time, it's health monitors who are walking out over pay.
They make annual radiation checks on equipment and staff.
The GMB Union says bosses at the nuclear reprocessing facility reneged on a pay deal.
Their members will take industrial action tomorrow; with another two-day strike planned from Wednesday.
Sellafield Ltd says the dispute won't affect operations; they added that they only opposed a blanket pay rise.