Dr Tim Gregory
Net zero commitments are colliding with grid reality. Boards backing renewables-only pathways are now confronting capacity, intermittency and supply chain constraints that their original decarbonisation plans did not price in. The question is no longer whether nuclear belongs in the transition, but how to think clearly about it without the ideological inheritance of the last forty years.
Tim Gregory is a nuclear chemist at the UK National Nuclear Laboratory who helps boards and policy audiences think clearly about nuclear power’s role in net zero, energy security and advanced industry.
Full Profile
Why organisations work with Tim Gregory
- He works inside the industry he speaks about. Day to day, he measures the chemistry and radioactivity of nuclear materials at Sellafield, which gives his policy arguments a footing most energy commentators do not have.
- His book Going Nuclear, published by Bodley Head and Pegasus in 2025, is a structured commercial case for atomic energy in the transition, not a general science book. Audiences leave with the argument, not impressions of it.
- He translates technical content for non-technical rooms. A decade of BBC science broadcasting, including The Sky at Night and BBC Breakfast, has trained him to take a board-level audience through reactor design, waste, and medical isotopes without losing them.
- He covers the adjacent commercial opportunities, not only generation: nuclear medicine, isotope supply chains, and nuclear power for space missions. This matters to boards in pharma, advanced manufacturing and aerospace, not just utilities.
- He is one of the few public-facing voices on nuclear who is a working scientist rather than a former regulator or executive, which gives him independence on contested questions about waste, safety and cost.
Biography highlights
- Senior nuclear chemist at the UK National Nuclear Laboratory, Sellafield.
- Author of Going Nuclear: How the Atom Will Save the World (Bodley Head/Pegasus, 2025).
- Author of Meteorite: How Stones from Outer Space Made Our World (John Murray, 2020).
- PhD in cosmochemistry, University of Bristol; MEarthSci First Class, University of Manchester.
- BBC science presenter and contributor: The Sky at Night, BBC Bitesize, BBC Breakfast, Channel 4 News, Sky News Australia.
- Final three on BBC2’s Astronauts: Do You Have What It Takes?, the astronaut selection series with Chris Hadfield.
- NASA Johnson Space Center intern, working on water-rich asteroids.
Biography
The UK plans to meet net zero with a grid that does not yet exist. Wind and solar capacity is rising, but firm low-carbon power is not. Gregory works at Sellafield, where the operational reality of nuclear, its fuel cycle, its waste, its economics, is closer than it is for most commentators on energy policy.
Going Nuclear, published in 2025 by Bodley Head in the UK and Pegasus in the US, sets out his argument in detail. It is not a defence of the existing nuclear estate. It is a case that atomic energy is the most environmentally responsible way to generate firm power, and that the wider applications of the atom, in medicine, forensics, agriculture and space, are systematically underweighted in public debate.
His credibility on the subject is anchored in primary research. He holds a PhD in cosmochemistry from the University of Bristol, completed a NASA internship at Johnson Space Center on water-rich asteroids, and wrote Meteorite (John Murray, 2020) about how the chemistry of meteorites maps the formation of the Solar System. That training in isotope chemistry is the same toolkit he applies at Sellafield.
He is also a working broadcaster. BBC Sky at Night, BBC Breakfast, BBC Bitesize and Channel 4 News have used him as a science contributor, and he reached the final three on BBC2’s Astronauts: Do You Have What It Takes? under Chris Hadfield. For boards working through the gap between net zero policy and capital allocation, he is rare in being both a practitioner and a public communicator on the same subject.
Key speaking topics
- Nuclear power and net zero
- Energy transition and capital allocation
- Nuclear waste, recycling and advanced reactors
- Nuclear medicine and isotope-based cancer treatment
- Nuclear power for space exploration
- Cosmochemistry and the formation of the Solar System
- Curiosity-driven research and commercial innovation
Ideal for
- Boards and executive teams in energy, utilities and infrastructure setting decarbonisation strategy.
- Investor and capital allocation audiences weighing nuclear exposure against renewables and gas.
- Pharmaceutical, advanced manufacturing and aerospace leadership teams interested in isotopes, nuclear medicine and space-grade power.
- Policy, regulatory and public-affairs audiences working on the UK and EU energy transition.
Audience outcomes
- A clearer view of where nuclear fits in a credible net zero pathway, and where the renewables-only argument runs out of road.
- Working knowledge of the economics and physics of waste, including why “waste” is increasingly a misnomer for current fuel cycles.
- A grounded read on nuclear medicine and isotope supply, and what it implies for pharma and healthcare strategy.
- A frame for thinking about nuclear-powered space missions and lunar or Martian infrastructure.
- The ability to push back, with data, on the most common public objections to nuclear power.
Talks
A direct case for atomic energy as the firm low-carbon backbone of any credible decarbonisation pathway.
Key takeaways:
- Why a renewables-only grid runs into capacity and intermittency walls
- The real cost and timeline picture for new nuclear build
- Where current government policy and capital allocation diverge
A reframing of so-called nuclear waste as feedstock for next-generation reactors, medical isotopes and deep space missions.
Key takeaways:
- What is actually in spent fuel and why it is not “waste”
- Recycling and reprocessing technologies now in development
- Commercial applications across energy, medicine and space
How radioisotopes are reshaping cancer diagnosis and treatment, and where the supply chain bottlenecks sit.
Key takeaways:
- The physics behind targeted alpha and beta therapies
- Why isotope supply is a strategic vulnerability for healthcare systems
- Implications for pharma R&D and capital investment
The role of atomic energy in lunar bases, Mars settlement, and long-duration missions where solar will not suffice.
Key takeaways:
- Why surface power on the Moon and Mars needs nuclear
- Current programmes from NASA and other agencies
- Industrial and supply chain implications for aerospace
A talk on how curiosity-driven research produces the commercial breakthroughs that targeted R&D often misses.
Key takeaways:
- Case studies from physics, chemistry and biology
- Why short-horizon R&D under-delivers
- How corporate innovation portfolios should treat fundamental research
A talk drawing on his book Meteorite and his work on Solar System formation, applied to organisational thinking.
Key takeaways:
- What meteorites tell us about planetary origins
- The discipline of working at long timescales
- Reframing organisational scale and risk through a cosmic lens