Two protesters have been arrested after blocking an entrance to a Ministry of Defence nuclear base.
Two people were arrested during the protests at Aldermaston
About 30 members of the Stop The Builders group halted traffic at the Aldermaston atomic facility, which is currently undergoing modernisation.
The protesters claim equipment to build a new generation of nuclear weapons is being installed at the Berkshire base.
An MoD spokesman said traffic had to use other entrances, adding: "The modernisation is not exactly a secret."
One of the demonstrators, Sian Jones, said: "We want the government to come clean, tell people what they are really building at Aldermaston and live up to their obligations under the non-proliferation treaty."
Sophie Bolt, vice chairman of the Campaign for Nuclear Disarmament, said: "The government has signed up to get rid of nuclear weapons and what is going on here at Aldermaston is the total opposite of that.
"It is a £2.2bn development which we believe will simply replace Trident."