Last month the government announced a temporary ban on Feltham A taking new inmates after an inspection found young people were being held there in "appalling" and "unsafe" conditions.
Chief inspector of Prisons Peter Clarke said that "significant and enduring support" should be provided to the YOI by government agencies, following an escalation in violence and self-harm.
An action plan published by the Ministry of Justice (MoJ) shows that the operational capacity at Feltham A has been reduced and new placements have been temporarily paused to assist improvement measures and refurbishment initiatives. The establishment can hold up to 140 young people, mainly aged 16 and 17.
"Placements will resume when the prison group director and governor judge that the establishment has achieved the necessary operational stability and can offer a full regime to all children," the action plan states.
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The MoJ said that a number of immediate changes in the wake of the scathing report, such as a specialist team working one-to-one with offenders in the prison, have already improved the situation and young people are now getting more time out of cells and in education, and a normal regime is running.
It said there have also been "major changes" to staff, including the appointment of a new head of safeguarding and the short-term secondment of Mike Woodbine, an experienced deputy governor from Cookham Wood YOI in Kent.
Meanwhile, by November, the prison hopes to have recruited a trauma expert to help staff better understand some of the reasons driving challenging behaviour at the prison, such as young people who have experienced domestic abuse or sexual violence.
And it said significant refurbishments have already begun, and work has also been undertaken to prepare young people for their transition back into the community, by prioritising family contact and working to help local authorities implement a scheme that will identify suitable accommodation one month before release.
Justice Secretary Robert Buckland said: "We are urgently making the improvements Feltham A desperately needs - and starting to see results.
"These efforts will not be allowed to slow and I am working closely with the prison to change the culture and make Feltham A somewhere that young people can get the support and structure they need to turn their lives around."
However, Carolyne Willow, director of children's rights charity Article 39, said the establishment should be closed.
"The chief inspector's letter last month set out a desperate, intolerable panoply of failures to meet basic levels of care and protection. Many of the 70 actions published by the Ministry of Justice today are rudimentary building blocks for any children's residential setting, including the appointment of a head of safeguarding, staff training and adequate shower facilities.
"But the biggest problem is: we have been here before. And before that. Feltham has a very long and sad history of severe child suffering.
"Ministers should have taken the chief inspector's letter as the final confirmation that the institution cannot be saved. Today's announcement should have been bold and principled, signalling the closure of Feltham and investment in approaches and services known to turn around young lives.
"This document with its 70 targets is about rescuing a prison which started its life in the 1800s; if it was truly about children, it would be a closure plan."