Mrs Mortimer raised the issue in the House of Commons as Hartlepool Power Station is due to be decommissioned in just three years time.
And writing in her Hartlepool Mail column today, she said she has also written to Business Secretary Kwasi Kwarteng to lobby for a replacement reactor.
Mrs Mortimer said in the commons that nuclear energy was currently the most affordable large scale low carbon source of energy in the UK and argued it must play a key role in achieving the country’s net zero CO2 commitment by 2050.
She said: “Although Hartlepool Power Station is one of EDF’s most productive power stations supplying low carbon electricity to 2.3 million homes and provide 730 high-skilled high wage jobs in my constituency it is also to be decommissioned by 2024.
"A debate on this topic would allow me to continue making the case for a new nuclear reactor for Hartlepool which would supply my constituency with thousands of new high-skilled jobs and ensure the success both of levelling up and building back better in the North East.”
Leader of the House of Commons, Jacob Rees-Mogg, said: “I think there may be opportunities to discuss nuclear power in this house in the not too distant future, because it is an important subject as nuclear does have a key role to play in helping us to achieve our net zero objectives".
He highlighted the building of EDF Energy’s new generation of nuclear power station at Hinkley Point in Somerset and added: “I think the community of Hartlepool can be very proud of its production of low carbon electricity for over 30 years”.
Mrs Mortimer also raised the need for a new Hartlepool reactor during a debate on Carbon Capture and Storage at Westminster Hall.
Writing in the Hartlepool Mail on Thursday, October 28, she says: "To this end, I have recently written to Kwasi Kwarteng, Secretary of State for Business, Energy and Industrial Strategy to lobby for a replacement reactor.”
Labour leader Sir Keir Starmer visited the power station in the run up to May’s Hartlepool by-election when he said he was “surprised” decisions about its future had not been made.