It's 50 years since the start of operations at the Magnox reprocessing plant at Sellafield in Cumbria.
The plant opened in 1964 and to date, it has reprocessed 52 thousand tonnes of radioactive waste from Magnox power stations in the UK.
Thousands of people have worked there, it now employs around 400.
To mark the facility's 50th birthday, 50 former workers were invited along, including one engineer who was there on the very first day it opened.
Our cameras were allowed in for the first time in half a century. Matthew Taylor reports.
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Christian Pay's family say he was "loved by all" and had "the heart of a lion". The 18-year-old died after falling ill at the festival.