Test explosion are being carried out on giant cooling towers at the Sellafield nuclear reprocessing plant in Cumbria.
The cooling towers will soon vanish
The controlled blasts over the weekend will bring the demolition of the four cooling towers a step closer.
Experts will study small segments of each tower to determine how much explosive will be needed to bring down the whole structure later this year.
The test blasts will not be visible off site, but will be able to be heard for some distance.
Project superintendent Jack Williamson said: "Carrying out the test blasts is a significant milestone for the project.
"Safety has been and remains the number one priority and the data gathered from the test blasts will enable us to ensure the towers are demolished in the safest possible manner."
Each pair of towers will be tested separately and the demolition team will then analyse the data gathered and use it to prepare for the final demolition.
The demolition of the towers is part of the Cumbria-based Nuclear Decommissioning Authority's plan to dismantle ageing facilities throughout the UK.
The towers were originally part of the Calder hall facility, which the world's first nuclear reactor and opened by the Queen in 1956.
Calder Hall ceased operating in 2003 after almost 50 years in service.