Protests are expected when the nuclear submarine HMS Trafalgar arrives in Southampton later.
The sub caused a scare last month when hundreds of litres of coolant spilled into the River Tamar while it was being worked on at Devonport in Plymouth.
The vessel also ran aground off the coast of Skye in November 2002.
It is the first visit by a nuclear submarine since 2006 and campaign group Solent Coalition Against Nuclear Ships (Scans) is planning a dockside protest.
"There is no need to put this incredibly busy commercial dock and the public at risk"
A spokesman from the Royal Navy said that the leak only occurred in Devonport because the submarine was undergoing maintenance.
He said the likelihood of a Royal Navy submarine being involved in an incident was extremely remote.
He added that in the 40 years that these submarines had been operation no radioactive material has been released into the environment.
Scans claims all emergency services in the city are on standby in case there is a problem with this 27-year-old submarine.
David Hoadley, Chair of Solent Coalition Against Nuclear Ships, said in a statement: "There is no need to put this incredibly busy commercial dock and the public at risk, when naval bases at Portsmouth and Plymouth are near at hand for nuclear submarines."
The submarine is hosting 18 visits by cadet and scout units - plus college students on public service courses - from across the city and Hampshire, according to the Royal Navy.
Some 280 litres of liquid escaped from HMS Trafalgar after a hose ruptured during the transfer of primary coolant to an effluent tank on a jetty.
It later emerged that although the leak happened on 7 November Plymouth City Council, which is responsible for emergency planning, was only told on 11 November.
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