The university and its Dalton Nuclear Institute will use the money to expand and develop its nuclear research programme and provide education and training to the next generation of nuclear industry professionals.
Under the terms of the endowment, a series of professorial chair appointments will be made, lasting up to five years in a number of research areas.
The money will also be used to cover associated costs such as support staff, fellowships, studentships, equipment, conferences and travel.
At the end of the funding period for each chair, it is expected the position will be financially sustainable via self-generated research income.
The endowment fund from BNFL will be known as the BNFL Endowment for Nuclear Research. The first professorial appointment is expected to be a BNFL chair in radiation effects on materials.
Michael Parker, group chief executive of BNFL, said: ‘For more than 35 years BNFL has been at the heart of nuclear education and research, particularly in the north west.
‘I am therefore delighted that we can provide this endowment to Manchester University’s internationally renowned Dalton Nuclear Institute to support the nuclear scientists of the future.
‘The £5million legacy that BNFL is providing will assist in ensuring that nuclear research in the north west continues to be rightly at the heart of the global nuclear renaissance.’
The announcement follows the university’s plans to establish a Centre for Nuclear Energy Technology (C-NET) in the north west with support from the Northwest Science Council and key industry partners.