The amendment tabled by former Conservative minister Ed Vaizey MP and Labour chair of the BEIS committee Rachel Reeves MP.
Mike Clancy, general secretary of Prospect said: "Leaving Euratom presents real danger to the UK nuclear sector.
“The sector provides thousands of highly skilled, highly productive jobs as well as playing a vital role in keeping the lights on.
“There is no convincing case for leaving Euratom, however if we are leaving time is now running out for the government to set out a proper action plan to deal with nuclear cooperation, funding and safeguarding.
“Prospect members will be urging MPs to support this sensible, cross-party amendment that will provide reassurance that Britain’s nuclear industry won’t face a damaging cliff edge.”