In February 2017, interested Member states/Associated countries, stakeholders and the European Commission held a kick off meeting of the SET Plan temporary working group on Nuclear Safety (TWG10). Meetings were held on a monthly basis and a 2 days' workshop last July gathering all relevant EU/MS stakeholders. TWG10 Implementation plan identifies a set of concrete research and innovation Fission/Fusion activities and key enabling conditions needed. It benefitted from the latest strategic research and innovation EU/MS programmes, roadmaps and deployment strategies of technology platforms or fora, all in all stimulating further EU/MS and Public/Private Joint Actions. Key funding opportunities have also been identified to achieve the agreed targets of the Declaration of Intent. The TWG10 was chaired by the United Kingdom and co-chaired by Belgian and French national ministry representatives. Formal notification of endorsement of this Implementation Plan was received from: BE, CH, CZ, ES, FI, FR, HR, HU, IT, LT, NL, PL, RO, SI, PL, TR & UK, following the SET Plan Steering Group meeting on 13th February 2019. This Implementation plan was only endorsed by the interested Steering Group members at the meeting held on 30 April 2019.