An emergency exercise is due to take place tomorrow morning on the Sellafield site.
The exercise may involve the sounding of the site siren, which may be heard off-site, and the use of pyrotechnics.
On this occasion, no action needs to be taken.
A spokesman said: "We apologise for any inconvenience caused to the local community."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here