This is currently one of the most exciting and dynamic periods for UK nuclear science & engineering since the 1950s. Inter alia, both new reactor build (essential to meet climate change targets) and the decommissioning of the UK's legacy nuclear sites (a 120 year, £121 bn programme) are driving forward, BEIS are investing heavily in the new national nuclear innovation programme and the sector deal for the industry has just been published. The already acute need for skilled nuclear scientists and engineers is therefore increasing and will continue to do so into the long term. To address these needs we propose a CDT in Nuclear Energy (GREEN), a partnership between 5 of the UK's leading nuclear universities and 12 industry partners, addressing EPSRC priority area 19: Nuclear Fission & Fusion for Energy. Evolving from the very successful Next Generation Nuclear (NGN) CDT, GREEN will deliver comprehensive doctoral training across the whole fission fuel cycle as well as in allied areas of fusion. Inspired by changes in external drivers and feedback from alumni, employers and funders, GREEN will offer both academically- and industrially- based research pathways, linked to enhanced employability training. We will further widen our already strong industry engagement by inclusion of new external partners, and align closely with other national and international activities, including other proposed CDTs. Experience from NGN suggests we will be able to leverage EPSRC support to give a typical cohort size of 15-20 students. Remarkably, using the leverage of 40 studentships from EPSRC, GREEN has already secured a further 47 studentships from Industry and Academia, ensuring a minimum number of 87 students in the GREEN CDT.