The US group that led construction of the Olympic Park and a New York-listed rival are the latest companies considering bids to oversee the UK's £5bn nuclear decommissioning programme.
CH2M Hill, which worked on London 2012 as part of the Olympic Delivery Partner team, and Aecom are both thought to be interested in buying the UK business of Utah-based Energy Solutions. This operates and decommissions Britain's oldest nuclear reactors and has already attracted a host of potential bidders, including US giant Bechtel and FTSE 100 group Amec.
The Nuclear Decommissioning Authority wants a deal in place by the end of next month. Goldman Sachs is believed to be handling the sale, which would value the business at about £50m.
There are 12 sites — nine are Magnox stations that are at different stages of decommissioning while a tenth, at Wylfa in Anglesey, is expected to stop producing electricity in two years. The remaining sites are former research centres where scientists experimented with the UK's earliest reactor designs.
A source close to the sale process said that CH2M Hill had the necessary experience, having cleaned up and closed a huge nuclear facility in Rocky Flats, Colorado, while Aecom is well-regarded in nuclear new build and decommissioning.
The sale happens as interest in Horizon, which will invest £15bn in new nuclear plants in Anglesey and Gloucestershire, heats up. The government's plans for the next generation of nuclear plants seemed in tatters when German utilities RWE and E.on said they were selling Horizon, but two Chinese state-owned outfits are interested in buying the joint venture.