The university said the whole higher education sector was facing similar issues and that while student numbers had increased it had to rebalance student-staff ratios.
It said the proposed loss of the equivalent of 92 full-time posts equated to less than 9% of its academic workforce across the three colleges that sit within the university.
It also said the TPS entitled staff to have 28.68% of their salary paid into the pension by the university which was “simply unaffordable”.
The union said it had received correspondence from university management which suggested 25 academics would go in the school of economics, finance and accounting with another 40 going in the college of arts, 25 in engineering and another 28 in a merger of two other departments.
It said it believed staff could be forced to leave as soon as March next year.
The university has said it would not comment on numbers of staff were UCU members.