UK commits to new nuclear plant, and robot surgery
In this edition of The Naked Scientists: the UK commits to building a new nuclear power station. But is it worth the hefty price tag? Also, how robots are revolutionising surgery. We’ll ask what they can and can’t do. And, how NASA’s top scientists track rogue near-Earth objects with remarkable precision...
In this episode
Billions for new UK nuclear
Simon Taylor, University of Cambridge
The UK government has committed more than £14 billion to build Sizewell C, a new nuclear power station on the Suffolk coast. It’s been heralded as the biggest investment in nuclear energy for a generation, and ministers say the project will power six million homes, create thousands of jobs, and help to usher in what they call a golden age of clean energy. But it’s not without controversy. Opponents warn of ballooning costs, long construction delays, and higher bills for consumers. The project’s true price tag - and its value to Britain’s energy future - also remain hotly debated. I’ve been speaking with Simon Taylor, author of 'The Fall and Rise of Nuclear Power in Britain,' and expert in energy policy and finance at Cambridge’s Judge Business School…
Simon - The government has, for some time, wanted new nuclear to be part of its overall energy policy, not least because most of the old nuclear power stations in Britain have either closed or will be closing by the early 2030's. So, the idea of building some new nuclear stations is at least partly just to keep nuclear as part of the overall energy mix. That, in turn, is partly because it is a good idea in energy policy to have a range of options – not to put all your eggs in one basket.
Most of our energy in future is going to come from offshore wind, and that, on the whole, is a good and clean source of energy – but it isn’t always windy, so we do need alternatives. Nuclear has the advantage that it’s always on – it runs 24 hours a day.
Chris - How do the costs stack up, though, and why do projects like this tend to start with one price tag and, as we’ve seen with Hinkley C – which is another project on the opposite side of the country – suffer massive overruns? Why does this happen?
Simon - I think there are two aspects to this. Nuclear, in recent years, in both Western Europe and the United States, has had a very poor record in terms of construction. Several projects have gone well over time and over budget, and I’m afraid Hinkley Point C in the west of England is one of them. So, there’s something about building nuclear – at least in these countries – which we struggle with. It’s partly because we haven’t done it for a very long time. But there is a broader question over big projects – it’s not just nuclear. We’ve seen problems across the Western world. Doing big, complex construction projects always seems to bring trouble, and nuclear is a particularly complex type of construction.
Chris - The government are arguing that, because they’ve done it once for Hinkley C, it’ll be easier the second time for Sizewell C. Do you buy that?
Simon - The argument is that you learn by doing, and on the whole, there’s a lot of evidence for this. Hinkley Point C is actually two reactors, and the construction team say – and there’s every reason to believe them – that the second one has gone more quickly and smoothly than the first because they have learned from it. Sizewell C will be an identical copy, so, in effect, you’re building the third and fourth reactors, and there’s every reason to think, therefore, that it should go more smoothly. That said, construction costs have gone up in the UK in recent years, and it remains a complex project where things can go wrong.
Chris - When it is ultimately completed, what’s the business model for nuclear, and does that actually lead to cheaper energy? Or, when one takes all of this massive cost into account, is it actually a very expensive way to generate power?
Simon - If you compare an additional unit of electricity from solar or wind or nuclear, nuclear – at least in Britain, Europe, and the US – currently comes out a lot more expensive, because the capital costs are currently so much higher. However, if you look at it on a system basis, and you ask what it would cost to build a whole decarbonised electricity system, doing that without nuclear is probably possible – but it gets very expensive when you’re trying to decarbonise the last few units of electricity. You end up having to build a lot of extra wind or solar to cope with those periods when there’s very little wind or sun. In that context, having some nuclear – as long as the costs aren’t too high – can, overall, be a sensible decision. The government haven’t actually made that case very effectively, but there is modelling work to suggest that nuclear can make sense on a system basis.
Chris - And if we consider not pounds, shillings and pence – the physical financial cost of something – but we consider the carbon cost, is the case clearer for nuclear in those terms?
Simon - Well, the evidence on this, I think, is quite clear, because the Intergovernmental Panel on Climate Change looked at this in detail several years ago. On the basis of the whole life of a project – from construction all the way through the years of generating electricity – nuclear is pretty similar to solar or wind in having very low carbon emissions per unit of electricity generated. On that basis, nuclear can, I think, credibly be regarded as a low-carbon source of electricity.
Chris - One way to do nuclear is this one: big scale, big infrastructure, one plant that serves many. The other way of thinking about this – which has come up much more recently – is the devolved approach of small modular reactors, which are smaller in scale and footprint, and they serve a smaller area but do it in a more bespoke way. The argument is that they’re built on a production line and you make many of them – therefore, you make many economies of scale in producing them. Now, how do the two compare? How do they stack up? Because the government seem to be hedging their bets here. They’ve also said they’re going to invest in this technology. I think Rolls-Royce have got the gig for the UK. How do they look in comparison?
Simon - Traditionally, there have been economies of scale in nuclear, and that’s why, all around the world, people tend to build reactors with 1,000 megawatts or more of capacity – and that’s quite a big number – because there are fixed costs of clearing a site, security, insurance, regulation. All of these things have argued for building big. The argument for small modular reactors is that, if you can mass-produce them – so to speak, in a factory – you can get the unit cost of production down. The problem with big nuclear is that you’re building a very complex and very specialised machine, with lots of parts that are made specifically for that project. That type of manufacturing is always going to be more expensive than using standardised units that you can build at scale.
So, the idea of small modular reactors is a very good one in principle, because if we can get to the point where we’re producing large numbers of these things on a very controlled basis and we get the benefits of economies of scale, that should bring the costs down. The problem is that these reactors don’t yet exist. They are a concept, and the designs look very interesting, but no one has actually built them yet.
NHS rolls out major expansion of robot-assisted surgery
Mark Slack, Cambridge Medical Robots
Millions of people are set to go under the robotic knife over the next decade, as the NHS rolls out a major expansion in robot-assisted surgery. From cancer treatments and joint replacements to life-saving emergency operations, surgical robots are set to become a familiar sight in UK operating theatres. But what do they do? And what are the benefits? Mark Slack at CMR Surgical in Cambridge has pioneered the use of robot-assisted surgery, and I've been speaking with him…
Mark - Doing surgery by hand is extremely difficult, and only about 40% of surgery is done keyhole by surgeons holding the instrument by hand. The reason it's only 40% is that it's very difficult to do, and many people can't do it. Therefore, they continue doing open surgery. That's based on United States figures—60% is open.
The robot is quicker to train, quicker to master the technique, and enables more people to perform it. Therefore, it gives us the chance of increasing keyhole surgery from 40% up to 80 or 90%, and then all the benefits are realised.
Chris - How does it actually work practically, though, Mark? These robots—you make one generation of them, there are competitors—but generally, do they work by replacing the surgeon and ironing out his or her mistakes, or do they work by effectively making what the surgeon is trying to do a lot easier, so they're less likely to make mistakes?
Mark - At the moment, they do a few things. Number one, they shorten the learning curve. I can train a surgeon using my robot to tie a knot in about an hour. With straight-stick, old-style handheld laparoscopy, tying a knot probably requires 50 hours of practice, and many people never get it. So, you speed up training. Number two, it allows more people—who otherwise couldn't perfect handheld laparoscopy—to do it, and therefore more patients benefit.
Chris - What sorts of procedures do you think are immediately amenable to what Wes Streeting has as his vision? Could we point this at all surgical problems, or is it going to be a cherry-pick approach? Can we solve some surgical problems very, very well and narrow those waiting lists down, but still have some surgeries that we just have to do the good old-fashioned way—so there's still going to be waiting lists? Which is it?
Mark - I think you've got to be very careful not to over-egg it. I've always said there will never be a single robot that does everything perfectly. Some will do some things better; others will do different things better. Therefore, we need to build that evidence base to work out where each performs best. For example, I will not allow my robot to be used for early-stage cervical cancer, because current evidence suggests that open surgery for cervical cancer is better than minimal access. But there are areas where one approach really shines. In my system—the Versius—we've just finished a paediatric study, and one of the surgeons said, “How long will it take from the end of the study to getting the CE mark [European health and safety certificate]?”
I said, “Oh, I don't know, a few months. Why?” And he said, “I feel it would be unethical to go back to doing laparoscopic surgery, having seen how much better and safer the Versius robot is for paediatric surgery.”
But I think we don’t have all the evidence yet, Chris. One of the things we need to do is gather more evidence-based medicine on the ground—actually demonstrating the advantages. It will not always be everything, and we have to stick to the evidence.
Chris - But you're sort of doing that, aren't you? Because robots like yours are collecting data as you operate, and you can presumably benchmark how someone is performing.
Mark - Absolutely. If we look at the telemetry on our robot, with about 99% accuracy it can distinguish between a novice and an expert. That gives us glimpses of the future, where you might come in for your surgical appraisal, sit at the robot, go through a few exercises, and get marked by the robot on how well you're doing.
Chris - You know that Uber have got aspirations to have a fleet of unmanned taxis driving around London. Are we on the verge, Mark, with this sort of technology, of having a surgeon-free operation—where you go and get a robot to do the job for you?
Mark - If you'd asked me two years ago about autonomous surgery, I would have said “never, ever.” Part of the problem is respiration—when you breathe, all the organs move in different directions, and that’s not predictable. Therefore, it’s hard to understand how you’d programme that in for a robot to handle. The acceleration I’m seeing with large language models, AI, and everything else is so fast that I’m not sure I’d make that statement anymore. We are a software-driven robot. So I could see a situation where you get to a certain point in the operation and the robot says, “At this point, 5% of surgeons encounter the following complication—beware.” I can see aids coming in very quickly. I can see skills appraisal happening very quickly. And I’m no longer willing to say you won’t see autonomous surgery in certain areas.
15:20 - Asteroid destined for Earth may now hit Moon instead
Asteroid destined for Earth may now hit Moon instead
Sara Russell, NHM
It’s been revealed that an asteroid called YR4, once thought to pose a small threat to Earth, now has a slim but notable chance of hitting a different target - our Moon. New observations using the James Webb Space Telescope have refined its path, suggesting there’s a 4.3 percent chance of a lunar impact in December 2032. The asteroid’s original risk to Earth has now been downgraded to almost zero, but the story highlights the importance of tracking near-Earth objects with precision. Sara Russell is a planetary scientist at the Natural History Museum, and an expert on near-Earth objects…
Sara - YR4 is an asteroid, which is a small rocky body. We think it's about 50 to 60 metres across—so think about the size of an Olympic swimming pool. It's a pretty big rock. It originally came from the asteroid belt, but now it orbits in a path very similar to that of the Earth—a similar distance from the Sun. That's why it's being tracked as something that could potentially be hazardous, as its path might one day overlap with the Earth's. It's being monitored very carefully, and there is a chance it might hit the Earth's Moon, which would be an incredibly exciting event for planetary scientists to observe.
Chris - Where do we think it would likely hit, and would we be in a position to see it?
Sara - Yes, so we think, as we see the Moon, it would be kind of on the edge, so it would be visible to people on Earth—which just makes it a fantastic observing opportunity for us.
Chris - But would it be an Earth-based observation, or have we got craft in space that could turn their eyes on this as well?
Sara - Hopefully both. It would be very visible using telescopes, even amateur telescopes on Earth, but there are a lot of satellites around the Earth, and hopefully they will get an even better view of the impact happening.
Chris - Obviously, there's only a slim chance it's going to happen, but if it does, could it have any negative consequences—or is it so small in comparison to the size of the Moon that it's just going to make a splat and that's all?
Sara - Yes, it would just make a splat. It's not big enough to shift the Moon's orbit or anything like that. It will make a crater. Typically, an impactor will create a crater that's at least ten times bigger than the impactor itself—so it will be at least 500 metres across, maybe more. The Moon will have a new crater that we can study, and that's actually really useful for people who study impact cratering, which is a very important process across our whole solar system. It's used, for example, for age-dating surfaces. We can estimate how old a surface is by counting how many craters it has on it, so understanding this process in more detail is always a great thing to do.
Chris - One planetary geologist put it to me a few years ago that geologists love an impact because it saves them having to do any digging. It basically scratches the surface and you can see what's in there—nature’s done it for you.
Sara - Yes, that's right. The very top surface of the Moon has been quite battered by the solar wind, for example, and tiny little micrometeorites. So, for example, it's a lot darker than the rock that's underneath—and these craters excavate some fresh material for us to look at. So yes, that's another great thing about craters. We love craters.
Chris - But in broader terms, does the fact that we're now on this like a hawk—we're able to see it, refine its trajectory, and then dismiss it as a threat to Earth—speak volumes about how prepared we are for this sort of thing now?
Sara - Absolutely. This is a fantastic result of the new generation of telescopes like James Webb, but also Vera Rubin, which is going to come online soon. These can look out for rocks floating around in space, even fairly small ones. In astronomical terms, 50 or 60 metres is considered a fairly small rock, but we can track them all—and that really helps ensure we can keep the Earth safe. It’s all part of a process called planetary defence: making sure we can work out if anything is going to hit us in the future, and if so, we can scramble plans. There are things we can do—if we have enough time, we can launch a spacecraft to nudge it out of the way and ensure the Earth is protected in a way it hasn’t been over geological time. Over the history of the Earth, there have been many impacts, some of them very, very big ones—but hopefully that won’t happen in the future because of the work astronomers are doing to track potential threats.
Chris - That's reassuring. And lastly, Sara, when we normally talk to you, you're telling us about your pet project, which is Bennu. You've got bits of that sitting on your desk and in your laboratory. You're still delving into it. Have you got any fresh insights to share with us yet?
Sara - Oh my goodness—actually, Chris, I’m studying Bennu in the lab today. I always get excited when I’m looking at Bennu because we always find new things. Today, we found a little clast inside the material that was brought back, which looks slightly different from all the other stuff. So, we don’t know—it might actually be the result of an impact on the surface of Bennu from another body.
Chris - So, an asteroid got hit by an asteroid? Is that what you're saying?
Sara - It might be a piece of a different asteroid, yes, that has been implanted into Bennu. So yes—but we're figuring it out.
21:23 - Our Palaeolithic ancestors used whale bones as tools
Our Palaeolithic ancestors used whale bones as tools
Jean-Marc Petillon, French National Centre for Scientific Research
Archaeologists have unearthed what may be some of the earliest known tools crafted from whale bones. Dating back as far as 20,000 years, the discovery opens a new chapter in our understanding of how early humans made use of marine resources that washed up on European shores. Jean-Marc Petillon, an archaeologist at the French National Centre for Scientific Research in Toulouse, has been leading the research.
Jean-Marc - People who lived in Western Europe about 20,000 to 15,000 years ago made part of their equipment using bone and antler. About 15 years ago, we realised that some of them were made of whale bone—but that was just a visual identification. We couldn’t say more than “it’s a whale.” The others were rather poorly dated because many of them come from ancient excavations. What we did in this study is that we managed to analyse them directly by sampling a tiny part of each object to identify the species—the whale species—and to give them a date.
Chris - Where were the specimens recovered from?
Jean-Marc - The objects we analysed are from about 27 sites, mostly cave sites or rock shelter sites, either on the northern coast of Spain or in south-western France, particularly the Pyrenees area.
Chris - So, would the individuals who had these things have gone locally to get these whales? Or does this tell us anything about people trading objects like this, moving objects like this?
Jean-Marc - The place where they got the whale bones is obviously the shore of the Gulf of Biscay, and some of our sites are not very far from the shore. But many of them are up to several hundred kilometres from that prehistoric coastline. And it's not the first time that objects travelled far from their source. At that time, we have seashells, for example, that were perforated and used as pendants, which can be found about 400 kilometres from their original place of collection.
It’s always difficult for us to know whether these were the same people travelling to and from the coast over hundreds of kilometres—because they were nomadic people at the time, of course—or if they were different groups exchanging and trading objects. It's actually quite difficult to determine. We don't really know the size of the territory occupied by a single group at that time.
Chris - What were they turning them into?
Jean-Marc - Most of the tools they made out of whale bone were projectile points—spear points—part of their hunting equipment. Some of them are quite long and wide. We have fragments that are more than 35 centimetres long, and they're only fragments, so the complete object must have been at least 40 centimetres.
They were probably crafted into rather large projectiles, like lances or spear-type weapons, rather than arrows, for example. Most of them are found as fragments, with fractures linked to their use. So, they were used in hunting, broken during use, and discarded on the cave floor.
Chris - How do you know it's whale bone, though? Because there were other big animals around at the time that could also have provided large bones—you could have done all those things you mentioned with them. So why did they go for whales? And how do you know these are whales?
Jean-Marc - Land mammals have a marrow cavity inside the bone, and whales don’t. In whales, the marrow is distributed throughout the whole thickness of the bone in small pores. So, when you look at the bone in detail, it has a specific porous structure not found in land mammals.
That’s how we first identified them 15 years ago. But the precise species identification—whether it’s a blue whale, a sperm whale, or whatever—comes from a completely different technique. It's palaeoproteomics, specifically a method called ZooMS. We sample a tiny part of the object, and the collagen in the sample is analysed. Collagen differs from one species to another. We then compare the result to a reference library, which allows us to say, “Okay, this small worked fragment that we couldn't identify with the naked eye is made from a fin whale,” for example.
Chris - Can those proteins also be dated? Is that how you can be sure when the people were exploiting these whales?
Jean-Marc - Collagen is a wonderful molecule because it has many uses for analysis, and one of them is dating. It’s used in the classic radiocarbon dating method. What is rather new in our study is that we used a specific technique called the MICADAS microcarbon dating system. We prepare the sample in such a way that we can date very small amounts of material. That was necessary here, of course, because these objects are few in number, small, and of high heritage value—so you can't just cut one in half and send half to a dating lab.
Chris - And what date do these objects come from, then? And where were the people getting the whales from? Were they actually catching the whales? Or were these people seashore dwellers, and occasionally a carcass would roll in—and that’s a valuable commodity?
Jean-Marc - Most of the species we identified are very large whales—fin whales, sperm whales, blue whales, grey whales—which were not hunted until fairly recently. We can’t really imagine that they had the techniques and technology at that time to hunt those whales. And, by the way, there’s no evidence of seafaring or boats from that period, and no signs of settlements on islands either. So, the most likely hypothesis by far is that they were using natural strandings or drift whales that came ashore.
How big is a photon?
Thanks, Donald. It’s a simple sounding question, but as you’re about to hear - the answer takes us deep into the strange world of quantum physics.
Marushka -A photon is a tiny packet of energy that makes up all forms of light from the electromagnetic spectrum; from long radio signals, to the warm glow of a candle, to the searing rays of a gamma burst. Unlike atoms or molecules, photons don’t have mass or internal structure.
So what exactly are they, and do they have a size? We called up Professor Ben Allanach, a theoretical physicist at the University of Cambridge, to help us shine some light on it…
Ben - The answer to that is a bit complicated. The short answer is no, not really. Because it’s a particle, it’s a quantum object, so it travels like a wave. They’ll interfere like ripples in a pond. But photons are ejected and absorbed as if they were point-like objects. It will hit the back of your retina like a point, but it will interfere with other photons in your eyeball like a wave, so it’s a bit of both. It's one of these weird quantum objects.
Marushka - In quantum physics ‘point-like objects’ have no measurable size at all - no radius, no width, no volume. We can’t give photons a “size” when we think about them in this way. But because photons also behave like waves sometimes, does that give us one way to talk about their “size”: their wavelength?
Ben - You can’t measure its size directly. But, you can only detect them if the thing that you’re detecting is of roughly the right size as the wavelength. That’s why satellite dishes are 30cm wide because that’s roughly the wavelength of the photons you’re detecting. Those are radio waves, which can be metres or many centimetres long. Whereas visible light is more like 500 nanometres (half a millionth of a metre) and if you decrease the wavelength, you get x- rays and then gamma rays which come from space and so on.
Marushka - So, Donald, to answer your question: a photon doesn’t really have a size in the way we’re used to thinking about things. It has no surface or an inside - it’s a quantum ripple that can stretch across space depending on its energy. It has properties related to its wavelength, but still acts like a point when it hits something.
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