Sellafield is looking for four partners to work on delivering projects at the west Cumbrian site over the next 20 years.
The programme and project partners model is set to be launched this week when interested parties will attend an industry day.
This process has been described as a "game changer" by Sellafield's management.
Projects director for Sellafield, Steve Livingstone, said: “This is a hugely important step for Sellafield Ltd – it is a game change for the way we deal with our supply chain.
“Instead of procuring supply chains for each major project, we’ll establish a new project delivery environment based upon long-term relationships with selected partners, developing closer working practices on the way.
“The new model will ensure our projects, while maintaining our excellent safety performance, will be delivered faster, meaning Sellafield is made safer more quickly.”
Sellafield’s decommissioning programme has a complex portfolio of major projects stretching over many decades.
The company has said the model has been designed to help deliver the next 20 years of this "safely, efficiently and cost effectively, through more collaborative and sustainable ways of working".
The event will be hosted by Sellafield on Friday (28 April).
This search comes at the same time as Sellafield has also published its new transformation plan and corporate strategy.
These documents outline the way the firm will work to make the site in west Cumbria safe and are the first of their kind since it became a wholly-owned subsidiary of the Nuclear Decommissioning Authority (NDA) last year.
Reprocessing work is set to finish at the Sellafield site in 2020 and the plans outline how the company hopes to save £1.4bn or more between this date and 2030.
Paul Foster, chief executive, said: "Transforming our organisation and the way we work with our supply chain will help our communities build greater resilience, demonstrate the longer-term future of our nuclear capability, and attract inward investment and economic growth."
Both documents can be read via www.sellafieldsites.com.
Subscribe to our newsletter: get a glimpse of what it's really like to live and work in Cumbria.