1 00:00:04,560 --> 00:00:07,680 This is Geology Bytes with Oliver Strumple. 2 00:00:09,320 --> 00:00:13,120 Radioactive waste is the byproduct of activities that use 3 00:00:13,120 --> 00:00:16,239 natural or man made radioactive materials. 4 00:00:16,840 --> 00:00:20,800 The main sources of radioactive waste are nuclear power stations 5 00:00:20,800 --> 00:00:23,920 and military activities. But while many of the 6 00:00:23,920 --> 00:00:27,440 radioactive isotopes present in radioactive wastes have 7 00:00:27,440 --> 00:00:31,320 relatively short half lives measured in decades, some 8 00:00:31,320 --> 00:00:35,560 isotopes have much longer half lives measured in thousands, 10s 9 00:00:35,560 --> 00:00:38,080 of thousands, or even hundreds of thousands of years. 10 00:00:39,000 --> 00:00:42,520 So to dispose of such waste, we need to be thinking of time 11 00:00:42,520 --> 00:00:46,280 scales that approach geological time scales which are orders of 12 00:00:46,280 --> 00:00:49,480 magnitude greater than any time scales associated with human 13 00:00:49,480 --> 00:00:53,800 civilizations. This has LED us to create deep 14 00:00:53,840 --> 00:00:58,400 geological storage sites. What sort of geological context 15 00:00:58,400 --> 00:01:02,280 do such storage sites require, and what kind of hazards do we 16 00:01:02,280 --> 00:01:04,800 need to guard against on such time scales? 17 00:01:06,120 --> 00:01:09,640 Claire Corkill is leading the UK's research efforts to 18 00:01:09,640 --> 00:01:13,360 understand and improve the safety of planned geological 19 00:01:13,360 --> 00:01:16,680 waste facilities. Her research focuses on how 20 00:01:16,680 --> 00:01:20,280 radioactive isotopes interact with minerals and on how 21 00:01:20,280 --> 00:01:23,040 radioactive waste can dissolve in groundwater. 22 00:01:23,960 --> 00:01:27,280 She's professor of Mineralogy and radioactive waste management 23 00:01:27,280 --> 00:01:30,560 in the School of Earth Sciences at the University of Bristol. 24 00:01:31,520 --> 00:01:34,160 Claire Corkill. Welcome to Geology Bites. 25 00:01:34,400 --> 00:01:35,720 Thank you very much for having me. 26 00:01:36,200 --> 00:01:39,400 Can you bring us up to speed on the nuclear processes that 27 00:01:39,400 --> 00:01:43,320 produce radioactive waste? So let's start with what happens 28 00:01:43,320 --> 00:01:47,800 inside a nuclear reactor. We start with uranium dioxide 29 00:01:47,800 --> 00:01:52,280 fuel and the uranium. When uranium 235, a specific 30 00:01:52,280 --> 00:01:56,040 isotope of uranium, is bombarded by a neutron, that causes the 31 00:01:56,040 --> 00:01:59,640 uranium atom to split, and in doing so it creates a huge 32 00:01:59,640 --> 00:02:02,760 amount of energy, and that energy is then used to heat 33 00:02:02,840 --> 00:02:06,040 water, turn it into steam, to turn turbines to create 34 00:02:06,040 --> 00:02:08,639 electricity. But the splitting process of the 35 00:02:08,639 --> 00:02:12,560 atoms also creates smaller atoms, and these smaller atoms 36 00:02:12,800 --> 00:02:17,000 are themselves unstable and their instability results in 37 00:02:17,000 --> 00:02:19,240 radiation. So these are fishing products 38 00:02:19,480 --> 00:02:23,280 that are developed inside the nuclear fuel and they can have 39 00:02:23,280 --> 00:02:27,200 radioactivity of some seconds all the way through to millions 40 00:02:27,200 --> 00:02:29,920 of years. So are those fission products, 41 00:02:29,920 --> 00:02:33,280 then, the main kind of radioactive waste that we are 42 00:02:33,280 --> 00:02:35,360 concerned with here? Yeah, exactly. 43 00:02:35,360 --> 00:02:38,440 So when we've finished with the fuel inside a nuclear reactor, 44 00:02:38,440 --> 00:02:40,480 there are a number of different things that we can do with that 45 00:02:40,480 --> 00:02:42,960 fuel. So the fuel can either be 46 00:02:43,200 --> 00:02:45,760 removed from the reactor, it's cooled for a while because of 47 00:02:45,760 --> 00:02:48,600 the radiogenic heat means it's actually quite hot to the touch. 48 00:02:48,600 --> 00:02:52,960 So it has to be cooled for a while in a wet pond or maybe in 49 00:02:53,000 --> 00:02:56,000 dry cask storage. That fuel can then either be 50 00:02:56,000 --> 00:03:00,600 disposed of directly, we call this an open fuel cycle or it 51 00:03:00,600 --> 00:03:03,080 could be reprocessed. And that's because that fuel 52 00:03:03,080 --> 00:03:06,640 contains useful uranium and plutonium that could be turned 53 00:03:06,640 --> 00:03:10,800 into new nuclear fuel. And so the reprocessing is the 54 00:03:11,120 --> 00:03:14,800 operation by which you dissolve down that nuclear fuel material 55 00:03:15,120 --> 00:03:18,040 through a liquid separation chemical separation process, you 56 00:03:18,080 --> 00:03:21,040 extract the uranium and plutonium and then everything 57 00:03:21,040 --> 00:03:24,080 else that's left, that is the fission product essentially. 58 00:03:24,080 --> 00:03:28,240 And those fission products, what we do is to dry them out. 59 00:03:28,800 --> 00:03:30,520 It's difficult to think about what this looks like. 60 00:03:30,520 --> 00:03:33,280 The dried out fishing products ends up looking remarkably like 61 00:03:33,280 --> 00:03:36,040 instant coffee granules. This is not the kind of stuff 62 00:03:36,040 --> 00:03:38,680 you'd want to put into your hot water to drink, but they look 63 00:03:38,680 --> 00:03:41,760 just like coffee granules. And these coffee granules are 64 00:03:41,760 --> 00:03:43,760 fishing products. They get mixed with a 65 00:03:43,760 --> 00:03:47,200 borosilicate glass which is very similar to the kind of dish that 66 00:03:47,200 --> 00:03:50,080 you would put into the oven to make your dinner and melted 67 00:03:50,080 --> 00:03:52,640 together and turned into a stable material. 68 00:03:52,640 --> 00:03:54,480 This is what we call high level waste. 69 00:03:54,480 --> 00:03:57,280 And so the spent fuel together with the glass we term high 70 00:03:57,280 --> 00:04:00,040 level waste. There are other items that are 71 00:04:00,040 --> 00:04:03,440 created through this process that are contaminated with 72 00:04:03,440 --> 00:04:06,840 radioactivity. So for example, the fuel pins, 73 00:04:06,840 --> 00:04:11,240 which are small pipes in which the nuclear fuel sits, these get 74 00:04:11,240 --> 00:04:15,560 split off from the fuel in the reprocessing operation and 75 00:04:15,560 --> 00:04:17,279 they're contaminated with the fuel. 76 00:04:17,279 --> 00:04:19,120 So we call this intermediate level waste. 77 00:04:19,120 --> 00:04:21,360 It has a smaller amount of radioactivity than the high 78 00:04:21,360 --> 00:04:23,600 level waste, but it's still quite radioactive. 79 00:04:23,600 --> 00:04:25,800 So there are lots of different types of waste that are 80 00:04:25,800 --> 00:04:31,120 generated through this process. So some of this waste has fairly 81 00:04:31,120 --> 00:04:34,680 long half lives. So do we try and extract the 82 00:04:34,680 --> 00:04:37,480 things that are likely to be problematic on the long term 83 00:04:37,480 --> 00:04:40,680 when we think about long term storage, or do we just take the 84 00:04:40,680 --> 00:04:42,400 whole lot and treat it all together? 85 00:04:43,000 --> 00:04:45,720 We essentially take the whole lot and treat it together so 86 00:04:45,960 --> 00:04:49,400 there are shorter half life isotopes like strontium 90, 87 00:04:49,400 --> 00:04:54,160 cesium 137 which have half lives around the order of 30 years. 88 00:04:54,440 --> 00:04:57,800 What ideally we'd like to do is leave these isotopes for up to 89 00:04:57,960 --> 00:05:00,840 10 half lives before they're considered to be safe. 90 00:05:00,840 --> 00:05:03,360 So the shorter ones like cesium and strontium. 91 00:05:03,400 --> 00:05:05,760 We only need to leave these a few 100 years, which means that 92 00:05:05,760 --> 00:05:09,680 we could store that waste probably in above ground storage 93 00:05:10,040 --> 00:05:12,880 units for 300 years. That seems like a reasonable 94 00:05:12,880 --> 00:05:15,160 thing to do and let the radioactivity decay. 95 00:05:15,480 --> 00:05:18,720 However, there are much longer lived isotopes and we're talking 96 00:05:18,720 --> 00:05:22,360 about things here like technetium 99, which is only 97 00:05:22,360 --> 00:05:25,640 made in a nuclear reactor. It has a half life of 200,000 98 00:05:25,640 --> 00:05:29,640 years and it's extraordinarily mobile in the subsurface. 99 00:05:30,000 --> 00:05:33,160 So we really have to think about these isotopes that are going to 100 00:05:33,160 --> 00:05:36,280 take much, much longer to decay when we think about how we're 101 00:05:36,280 --> 00:05:38,880 going to store them safely over the time scales that are 102 00:05:38,880 --> 00:05:40,120 required. OK. 103 00:05:40,120 --> 00:05:42,280 So that gets us to the geological storage. 104 00:05:42,280 --> 00:05:47,240 So you have mixed all this stuff together with this borosilicate 105 00:05:47,240 --> 00:05:50,240 glass. Do we just take all that, find 106 00:05:50,240 --> 00:05:54,960 deep geological storage, put it in there, lock the door and 107 00:05:54,960 --> 00:05:56,520 forget about it? How does that work? 108 00:05:57,120 --> 00:06:01,640 Well, really we have to try and find the best place to have a 109 00:06:01,640 --> 00:06:05,920 geological disposal facility. So what we're looking for is a 110 00:06:05,960 --> 00:06:09,640 location where we can safely isolate these wastes from future 111 00:06:09,640 --> 00:06:11,960 populations. And the time scales that we're 112 00:06:11,960 --> 00:06:14,400 looking at are really civilizations. 113 00:06:14,560 --> 00:06:17,400 So we really need to find a place that's going to be stable 114 00:06:17,400 --> 00:06:20,360 and secure, I guess over these really long time scales. 115 00:06:20,360 --> 00:06:23,560 And the time scale that most organizations who are trying to 116 00:06:23,560 --> 00:06:26,320 dispose of this waste are looking for is a million years. 117 00:06:26,840 --> 00:06:30,640 So there's really no better place to put this waste than in 118 00:06:30,880 --> 00:06:34,000 a stable rock formation that has been stable for probably 119 00:06:34,000 --> 00:06:36,640 billions of years, if not hundreds or 10s of millions of 120 00:06:36,640 --> 00:06:40,080 years. So when we think about the 121 00:06:40,080 --> 00:06:42,840 disposal of the waste, I don't want people to jump their minds 122 00:06:42,840 --> 00:06:46,040 straight to the kind of the Homer Simpson analogy where 123 00:06:46,040 --> 00:06:48,880 you've got glowing green goo that gets poured down a hole. 124 00:06:48,880 --> 00:06:52,400 That is not what this is at all. This is a highly engineered 125 00:06:52,400 --> 00:06:55,040 facility somewhere deep below the ground. 126 00:06:55,040 --> 00:06:58,960 We're talking around 200 meters to 1000 meters below the earth. 127 00:06:59,280 --> 00:07:02,520 You can imagine a series of large caverns and tunnels. 128 00:07:02,800 --> 00:07:06,600 And in these tunnels, we'll be placing containers of waste in a 129 00:07:06,600 --> 00:07:10,000 series of layers of containment that will ultimately prevent 130 00:07:10,080 --> 00:07:12,000 groundwater from reaching the waste. 131 00:07:12,080 --> 00:07:15,240 That will ultimately start to dissolve the radioactive things 132 00:07:15,360 --> 00:07:17,560 from inside the waste and transport them outside. 133 00:07:17,760 --> 00:07:20,120 That will inevitably happen over the long time scales we're 134 00:07:20,120 --> 00:07:22,520 talking about. So we use a series of layers of 135 00:07:22,520 --> 00:07:24,440 containment to try and prevent that from happening. 136 00:07:24,440 --> 00:07:27,600 So at that point, once we've disposed of the waste and we've 137 00:07:27,600 --> 00:07:30,040 backfilled the tunnels, then yes, we're going to lock the 138 00:07:30,040 --> 00:07:32,200 door. But there's a lot of engineering 139 00:07:32,200 --> 00:07:35,520 and thought that has to go into all aspects of that disposal 140 00:07:35,520 --> 00:07:38,360 facility before we can even think about Building 1. 141 00:07:39,000 --> 00:07:42,760 Let's go back to the selection of the site. 142 00:07:43,080 --> 00:07:46,920 Now, you mentioned geological stability and billions of years. 143 00:07:46,920 --> 00:07:51,160 So are we really looking for these ancient cratons that have 144 00:07:51,160 --> 00:07:55,520 essentially been left alone since the Neo protozoic, which 145 00:07:55,520 --> 00:07:58,520 are extraordinary stable? Are we really trying to find 146 00:07:58,520 --> 00:08:00,800 something that's geologically stable on that kind of time 147 00:08:00,800 --> 00:08:03,560 scale? Well, I suppose in a way those 148 00:08:03,560 --> 00:08:06,440 kinds of formations would be ideal, but it's not necessary. 149 00:08:06,440 --> 00:08:10,320 What we're really looking for is anybody of rock of the right 150 00:08:10,320 --> 00:08:13,640 volume required to dispose of the inventory of a particular 151 00:08:13,640 --> 00:08:16,960 country and it has to have certain properties. 152 00:08:17,400 --> 00:08:20,720 The most important point is that it has a very low permeability. 153 00:08:20,720 --> 00:08:23,720 So I mentioned water interacting with the waste. 154 00:08:23,720 --> 00:08:27,520 If we can reduce the likelihood of water coming into contact 155 00:08:27,520 --> 00:08:30,040 with the waste materials, then we reduce the likelihood of it 156 00:08:30,040 --> 00:08:33,200 dissolving the waste and transporting those radioactive 157 00:08:33,200 --> 00:08:36,039 isotopes away into the geosphere and the subsurface. 158 00:08:36,039 --> 00:08:39,799 So number one key criteria is to find a low permeability rock. 159 00:08:39,799 --> 00:08:43,320 Now lots of rocks are very non permeable, so clays are very non 160 00:08:43,320 --> 00:08:45,720 permeable. If we have a non fractured 161 00:08:45,720 --> 00:08:48,600 granite for example, that would be very, very low permeability. 162 00:08:49,000 --> 00:08:50,840 It could really be in any kind of rock. 163 00:08:51,120 --> 00:08:52,720 So we're also looking for somewhere that's very 164 00:08:52,720 --> 00:08:56,360 tectonically stable, somewhere where the rocks are not going to 165 00:08:56,400 --> 00:08:59,480 change significantly over a period of time of that million 166 00:08:59,480 --> 00:09:00,600 years. We're not going to have 167 00:09:00,840 --> 00:09:04,320 intrusions of granite or dykes or whatever coming through the 168 00:09:04,320 --> 00:09:08,400 geological disposal facility. We're also interested in it not 169 00:09:08,400 --> 00:09:13,240 being close to any resources. So the idea behind this is that 170 00:09:13,520 --> 00:09:17,160 a future population might find, for example, a coal deposit if 171 00:09:17,160 --> 00:09:20,280 fossil fuels are not completely extracted in the future, as one 172 00:09:20,280 --> 00:09:22,320 example. Or maybe it's a metalliferous or 173 00:09:22,320 --> 00:09:24,760 deposit. We don't want future populations 174 00:09:24,760 --> 00:09:27,680 to go, oh let's dig there and then accidentally stumble upon 175 00:09:27,680 --> 00:09:30,440 some really dangerous hazardous radioactive waste materials. 176 00:09:30,440 --> 00:09:33,800 So there are a number of different criteria that would 177 00:09:33,960 --> 00:09:36,640 make us think that a site is potentially suitable. 178 00:09:37,200 --> 00:09:42,000 So when we find an ideal site like this that has the right 179 00:09:42,000 --> 00:09:46,160 geological properties, do we use that for the waste from many 180 00:09:46,160 --> 00:09:48,960 different countries, or does each and every country have to 181 00:09:48,960 --> 00:09:53,160 have its own waste site? So at the moment, and this is 182 00:09:53,200 --> 00:09:56,520 unlikely to change, all countries have to dispose of 183 00:09:56,520 --> 00:09:58,840 their own waste. When we're talking about the 184 00:09:59,120 --> 00:10:01,960 higher activity, waste that comes particularly from nuclear 185 00:10:01,960 --> 00:10:05,520 energy, and some countries are sharing in other types of waste 186 00:10:05,520 --> 00:10:11,280 disposal, for example, the kind of cesium medical isotopes that 187 00:10:11,280 --> 00:10:14,960 are used in hospital facilities. These are quite small sources 188 00:10:15,240 --> 00:10:17,800 and some countries in Europe are starting to think about whether 189 00:10:17,800 --> 00:10:20,720 maybe they could share a borehole disposal facility for 190 00:10:20,720 --> 00:10:23,520 those kinds of wastes. But generally speaking, once 191 00:10:23,520 --> 00:10:26,680 you've created your own waste in your own country, you're 192 00:10:26,680 --> 00:10:28,680 responsible for it and you have to dispose of it. 193 00:10:28,960 --> 00:10:32,400 So what does the country like Japan do, which is, as I 194 00:10:32,400 --> 00:10:35,600 understand it, pretty much a volcanic island that's 195 00:10:35,600 --> 00:10:38,240 tectonically active and could have an earthquake anywhere. 196 00:10:38,680 --> 00:10:41,320 You're absolutely right. So Japan is a really interesting 197 00:10:41,320 --> 00:10:43,560 case. They are planning to build 198 00:10:43,560 --> 00:10:46,120 geological disposal facility for their radioactive waste. 199 00:10:46,120 --> 00:10:49,480 As we all know, Japan have a very long history of nuclear 200 00:10:49,480 --> 00:10:53,440 power and even past the 2011 Fukushima accident they've 201 00:10:53,440 --> 00:10:55,840 started up their nuclear power stations again. 202 00:10:56,240 --> 00:11:00,280 So they are looking at a variety of different areas in different 203 00:11:00,280 --> 00:11:04,000 types of host rock to try and identify somewhere that has a 204 00:11:04,000 --> 00:11:06,920 very low risk of tectonic disruption. 205 00:11:07,400 --> 00:11:09,600 So again, this comes back to the point that I said earlier, 206 00:11:09,600 --> 00:11:12,800 really any rock is suitable to be a geological disposal 207 00:11:12,800 --> 00:11:16,640 facility. It just needs to have a low risk 208 00:11:16,640 --> 00:11:20,880 of that radioactive waste being exposed to future populations. 209 00:11:21,080 --> 00:11:24,520 And if the organizations involved in disposing the waste 210 00:11:24,520 --> 00:11:27,520 can make their case to the safety regulators that that's 211 00:11:27,520 --> 00:11:30,840 the case, then they should be able to get a permit to build 212 00:11:30,840 --> 00:11:33,400 their facility. You just said that we want to 213 00:11:33,400 --> 00:11:37,440 minimize the risk of this waste coming to contact with human 214 00:11:37,440 --> 00:11:41,000 populations in the future. So it seems like the first thing 215 00:11:41,000 --> 00:11:45,880 is for something we don't really want to have happen, 'cause the 216 00:11:45,880 --> 00:11:50,680 radioactive isotopes to break free from the glass that we've 217 00:11:50,680 --> 00:11:54,880 put them into. So what exactly is the risk at 218 00:11:54,880 --> 00:11:56,480 that level? What do these radioactive 219 00:11:56,680 --> 00:12:00,720 isotopes do to their chemical and physical confinement inside 220 00:12:00,720 --> 00:12:03,200 this glass over long time scales? 221 00:12:03,720 --> 00:12:07,680 Yeah, so I'm going to take the example of alpha particles. 222 00:12:07,680 --> 00:12:11,120 So if we can all think back to alpha, beta, gamma radiation. 223 00:12:11,120 --> 00:12:12,560 So let's talk about alpha particles. 224 00:12:12,680 --> 00:12:14,840 If we think about an alpha particle, which is a helium 225 00:12:14,840 --> 00:12:18,200 nucleus, it's quite big and it's quite heavy and it moves with 226 00:12:18,200 --> 00:12:20,920 quite a lot of energy inside a material. 227 00:12:21,200 --> 00:12:24,440 So if we take, for example, a crystalline material, so we'll 228 00:12:24,440 --> 00:12:26,760 come back to glass in a moment. If we have a crystalline 229 00:12:26,760 --> 00:12:30,200 material where there are atoms arranged in a periodic 230 00:12:30,200 --> 00:12:33,400 structure, it has very nicely arranged long range order. 231 00:12:33,880 --> 00:12:37,560 As soon as the alpha particle hits an atom in that crystal 232 00:12:37,560 --> 00:12:41,880 lattice, it will displace it and it will displace that atom and 233 00:12:41,880 --> 00:12:43,720 there'll be a number of other displacements. 234 00:12:43,720 --> 00:12:46,200 So you can think of it a bit like a set of billion balls. 235 00:12:46,200 --> 00:12:48,680 You have the cue ball hitting the the triangle of balls and 236 00:12:48,680 --> 00:12:51,040 they just scatter everywhere. So that's what happens when an 237 00:12:51,040 --> 00:12:55,120 alpha particle hits the crystal lattice inside a crystalline 238 00:12:55,120 --> 00:12:57,840 material. And obviously the more the bonds 239 00:12:57,840 --> 00:13:00,880 that you break, the more lattice positions that you move. 240 00:13:01,280 --> 00:13:04,120 The properties of that crystalline material breakdown 241 00:13:04,120 --> 00:13:08,320 over time, and they start to cause a lot of damage, which may 242 00:13:08,320 --> 00:13:11,640 impact the durability. So if you break that crystalline 243 00:13:11,640 --> 00:13:13,800 structure down, it might be easier to dissolve it in the 244 00:13:13,800 --> 00:13:17,280 groundwater for example. So those radioactive decay 245 00:13:17,280 --> 00:13:21,080 processes inside the waste itself can be quite problematic. 246 00:13:21,080 --> 00:13:24,400 They can reduce the longevity, the durability of those 247 00:13:24,400 --> 00:13:27,440 materials. Now this is one reason why we 248 00:13:27,480 --> 00:13:30,360 use glass. So glass doesn't have that 249 00:13:30,360 --> 00:13:32,960 crystalline nice long range order structure. 250 00:13:32,960 --> 00:13:37,000 It's a bit like a frozen liquid where there's no real long range 251 00:13:37,000 --> 00:13:38,520 order. It's got short range order but 252 00:13:38,520 --> 00:13:40,400 not long range. So when an alpha particle 253 00:13:40,400 --> 00:13:43,600 smashes through that structure, it doesn't really matter because 254 00:13:43,680 --> 00:13:45,320 it's got no structure in the 1st place. 255 00:13:45,320 --> 00:13:49,480 So glass is a remarkably resistant to radiation damage. 256 00:13:50,040 --> 00:13:53,360 That's not to say that not all crystalline materials behave in 257 00:13:53,360 --> 00:13:55,520 the same way. Some crystalline materials are 258 00:13:55,520 --> 00:13:59,200 very resistant to radiation, and they actually have internal 259 00:13:59,200 --> 00:14:02,880 defects and self annealing repair mechanisms that can 260 00:14:03,200 --> 00:14:06,880 recover that damage. And therefore there are some 261 00:14:06,880 --> 00:14:09,200 crystalline materials that make excellent candidates for 262 00:14:09,200 --> 00:14:10,960 radioactive waste. But there are also some 263 00:14:11,120 --> 00:14:13,000 crystalline materials that would be terrible. 264 00:14:13,320 --> 00:14:15,920 So do we actually use some crystalline materials in fact, 265 00:14:15,920 --> 00:14:19,040 in addition to the glass? At the moment, no. 266 00:14:19,040 --> 00:14:21,960 But that brings us to something that I'm working a lot on in my 267 00:14:21,960 --> 00:14:26,640 research at the moment is trying to explore the use of certain 268 00:14:26,640 --> 00:14:29,760 titanate minerals. So we're interested in a couple 269 00:14:29,760 --> 00:14:33,960 of key players who are pyroclore and also zucconolite. 270 00:14:34,600 --> 00:14:38,960 These mineral structures are relatively radiation resistant. 271 00:14:38,960 --> 00:14:42,360 They do overtime become completely radiation damaged, 272 00:14:42,360 --> 00:14:44,640 they become amorphous overtime. This is a term we call 273 00:14:44,640 --> 00:14:47,400 metamictization. But despite this 274 00:14:47,400 --> 00:14:50,360 metamictization, which does happen over a very long period 275 00:14:50,360 --> 00:14:53,800 of time compared to other types of crystalline structures, they 276 00:14:53,800 --> 00:14:57,880 still retain the original uranium and thorium content that 277 00:14:57,880 --> 00:15:00,560 they started life with. And some of these minerals that 278 00:15:00,560 --> 00:15:03,520 I've been studying from the Canadian Shield, they're around 279 00:15:03,520 --> 00:15:06,920 about a billion years old and they still contain uranium and 280 00:15:06,920 --> 00:15:09,440 thorium that has been locked up in their structures for that 281 00:15:09,440 --> 00:15:13,240 amount of time. So we understand that even 282 00:15:13,240 --> 00:15:15,480 though these minerals have been subject to hydrothermal 283 00:15:15,480 --> 00:15:19,320 alteration, even though they're completely metamic, they could 284 00:15:19,320 --> 00:15:23,080 be good host candidates for actinide wastes that come from 285 00:15:23,080 --> 00:15:24,960 nuclear power. And the one that we're 286 00:15:24,960 --> 00:15:27,560 interested in at the moment is whether we could use these 287 00:15:27,560 --> 00:15:31,640 minerals as a template to create waste forms for plutonium. 288 00:15:31,720 --> 00:15:34,920 They could also be used potentially for actinides that 289 00:15:34,920 --> 00:15:39,080 come from future fuel cycles. So new types of nuclear reactor 290 00:15:39,080 --> 00:15:41,680 that haven't yet been invented. They're on paper at the moment, 291 00:15:41,680 --> 00:15:44,720 but they will generate types of waste that you could potentially 292 00:15:44,720 --> 00:15:48,480 use these crystalline materials for disposing of the waste 293 00:15:48,480 --> 00:15:51,280 products. But why would we ever want to do 294 00:15:51,280 --> 00:15:53,240 that? Do these minerals hold out the 295 00:15:53,240 --> 00:15:56,400 prospect that they're actually better than glass in terms of 296 00:15:56,400 --> 00:15:59,920 how they respond to radiation damage over 10s or hundreds of 297 00:15:59,920 --> 00:16:04,400 thousands or millions of years? So these crystalline materials, 298 00:16:04,400 --> 00:16:07,240 whilst they're not as good as glass at being resistant to 299 00:16:07,240 --> 00:16:09,240 radiation damage, they ultimately will become 300 00:16:09,240 --> 00:16:13,120 amorphous. The key factor here is that they 301 00:16:13,120 --> 00:16:15,480 are orders of magnitude more durable. 302 00:16:15,920 --> 00:16:18,280 So when you try and dissolve these materials, they are 303 00:16:18,280 --> 00:16:20,840 completely different. So glass is a very durable 304 00:16:20,840 --> 00:16:23,280 material, super durable. And you'll know this if you put 305 00:16:23,280 --> 00:16:25,960 glassware into your dishwasher, which is an extraordinarily 306 00:16:25,960 --> 00:16:27,760 harsh environment. If you think of all of the 307 00:16:28,120 --> 00:16:30,880 detergent and the soap and the, you know, the temperature and 308 00:16:30,880 --> 00:16:34,320 whatever you will see sometimes on the outside of your glass, 309 00:16:34,320 --> 00:16:37,600 this cloudy white layer, that's a corrosion layer on the glass. 310 00:16:37,600 --> 00:16:40,360 But you know, no matter how many times you put your glasses in 311 00:16:40,360 --> 00:16:42,600 the dishwasher, they don't completely dissolve, right, that 312 00:16:42,600 --> 00:16:45,000 it's a very durable material. And that's just the same for 313 00:16:45,000 --> 00:16:48,480 radioactive waste glass. If we put a fistful size of 314 00:16:48,480 --> 00:16:51,520 radioactive waste glass into a bucket of water, it would still 315 00:16:51,520 --> 00:16:53,800 be there after several hundreds of thousands of years. 316 00:16:54,000 --> 00:16:56,640 These are very durable materials and we can look into the 317 00:16:56,640 --> 00:17:00,000 geological record to see also glasses that are 10s of millions 318 00:17:00,000 --> 00:17:01,840 of years old. There are Obsidian glasses that 319 00:17:01,920 --> 00:17:06,720 a very old, but if we then go away and look at the titanate 320 00:17:06,920 --> 00:17:09,400 minerals, the there's econolites, the pyroclaws. 321 00:17:09,800 --> 00:17:13,319 They are several orders of magnitude more durable than 322 00:17:13,440 --> 00:17:16,720 glass, So they really win on the durability perspective. 323 00:17:16,720 --> 00:17:20,040 And the durability is important because when the groundwater 324 00:17:20,040 --> 00:17:23,480 comes into contact with these waste minerals, the process of 325 00:17:23,480 --> 00:17:26,359 dissolving out the radionuclides, it has to be as 326 00:17:26,359 --> 00:17:29,520 slow as possible for us to have confidence that those 327 00:17:29,520 --> 00:17:32,160 radionuclides aren't going to escape to the geosphere and 328 00:17:32,160 --> 00:17:34,400 they're not going to escape to the biosphere. 329 00:17:34,400 --> 00:17:38,040 And so crystalline materials for me, they win hands down on 330 00:17:38,040 --> 00:17:41,640 durability. ICC are saying even if each of 331 00:17:41,640 --> 00:17:46,280 these materials could be damaged, either the glass or the 332 00:17:46,920 --> 00:17:50,800 titanite as a colite, even the presence of water or 333 00:17:50,800 --> 00:17:55,280 hydrothermal fluids, we've seen that the minerals will not 334 00:17:55,280 --> 00:17:57,160 release the radioactive isotopes. 335 00:17:57,560 --> 00:17:59,200 Yes, exactly. So some of the minerals that 336 00:17:59,200 --> 00:18:02,560 I've been studying where you see these small hydrothermal veins, 337 00:18:02,560 --> 00:18:05,320 we think the temperature of those hydrothermal events was 338 00:18:05,320 --> 00:18:08,600 somewhere on the order of 300°C, which is much hotter than we 339 00:18:08,600 --> 00:18:12,000 expect any groundwater in the geological disposal facility to 340 00:18:12,000 --> 00:18:14,760 be. We do see slight leaching of the 341 00:18:14,760 --> 00:18:18,480 uranium, but it only ever is transported a very small 342 00:18:18,480 --> 00:18:20,560 distance. So we can have really strong 343 00:18:20,560 --> 00:18:23,760 confidence that these are really very durable materials. 344 00:18:24,160 --> 00:18:28,760 Are the uranium or the radioactive isotopes located as 345 00:18:28,760 --> 00:18:31,240 part of the crystal structure in these minerals or are they in 346 00:18:31,240 --> 00:18:34,280 interstitial sites? They're absolutely inside the 347 00:18:34,280 --> 00:18:37,720 main lattice structure. So if we take zirconalitis, 348 00:18:37,720 --> 00:18:41,640 prototypical formula is a calcium zirconium titanate, so 349 00:18:41,640 --> 00:18:48,080 CAZ RTI2O7 and so the uranium will sit either on the calcium 350 00:18:48,080 --> 00:18:50,320 site or on the zirconium site or both. 351 00:18:50,680 --> 00:18:52,800 And so it's very flexible. Same with the thorium. 352 00:18:52,800 --> 00:18:56,760 And that's how we're using that crystal structure as a template 353 00:18:56,760 --> 00:18:59,480 for synthetic materials where we can look at those and go, well, 354 00:18:59,480 --> 00:19:02,240 all right, we can maybe put some plutonium on the calcium site 355 00:19:02,240 --> 00:19:04,560 and we can put some on the zirconium site, but we might 356 00:19:04,560 --> 00:19:06,840 need to add some charge balance on the titanium site. 357 00:19:06,840 --> 00:19:08,680 So why don't we try and use some iron? 358 00:19:08,680 --> 00:19:11,480 So we just tinker with the chemical structure to try and 359 00:19:11,480 --> 00:19:15,160 recreate what nature has given us to find the most radiation 360 00:19:15,240 --> 00:19:18,760 stable, the most durable, the most long lived crystal 361 00:19:18,760 --> 00:19:20,360 composition that we can possibly find. 362 00:19:20,840 --> 00:19:24,400 So you mentioned that permeability is the number one 363 00:19:24,400 --> 00:19:27,680 criterion that we look for in these deep geological storage 364 00:19:27,680 --> 00:19:30,680 sites. But over the time scale we're 365 00:19:30,680 --> 00:19:35,320 talking about, can rocks change in their permeability or can the 366 00:19:35,320 --> 00:19:39,960 water level change so that these materials would eventually be 367 00:19:39,960 --> 00:19:44,000 exposed to circulating fluids? Yeah, that's a really good 368 00:19:44,000 --> 00:19:47,360 question. I think when the organizations 369 00:19:47,360 --> 00:19:50,520 who are looking at these particular sites to find out 370 00:19:50,520 --> 00:19:54,160 whether they're suitable, future change in, for example, sea 371 00:19:54,160 --> 00:19:58,000 level rise or other various climate changes, it's something 372 00:19:58,000 --> 00:19:59,800 they have to take into consideration. 373 00:19:59,920 --> 00:20:03,680 Will these changes affect how water is entering the site, how 374 00:20:03,680 --> 00:20:06,160 it's leaving the site? This is something that they'll 375 00:20:06,160 --> 00:20:07,880 have to ascertain. It's something that's very 376 00:20:07,880 --> 00:20:10,760 difficult to do. Most climate prediction models 377 00:20:11,040 --> 00:20:13,000 at the moment only go out to the end of the. 378 00:20:13,080 --> 00:20:15,400 This century and a little bit beyond, but what we're talking 379 00:20:15,400 --> 00:20:18,880 about now, a much longer time scales to be able to say, well, 380 00:20:18,880 --> 00:20:21,080 this is where we think the sea level will be and so on. 381 00:20:21,480 --> 00:20:25,000 So that is definitely something that will have to be looked at 382 00:20:25,000 --> 00:20:27,960 and taken into consideration when a site is being selected in 383 00:20:27,960 --> 00:20:31,400 the future. Where are the existing deep 384 00:20:31,400 --> 00:20:33,920 Geological Storage sites? Are there quite a few that have 385 00:20:33,920 --> 00:20:37,400 already in service? Well, despite this being 386 00:20:37,400 --> 00:20:41,520 something that has been rumbling on for many decades now, there 387 00:20:41,800 --> 00:20:46,640 are no operating facilities for high level radioactive waste in 388 00:20:46,640 --> 00:20:48,040 the world. But that doesn't mean to say 389 00:20:48,040 --> 00:20:50,440 that they're not being built in Finland. 390 00:20:50,440 --> 00:20:53,840 The Oncolo facility is being constructed right now. 391 00:20:54,400 --> 00:20:58,840 This is a facility that's being built in a very old nice, this 392 00:20:58,840 --> 00:21:03,920 very stable crystal in old rock and the construction is ongoing. 393 00:21:03,920 --> 00:21:06,000 I've been down. I had the lucky opportunity to 394 00:21:06,000 --> 00:21:09,480 drive all the way down. It's 475 metres below ground. 395 00:21:10,160 --> 00:21:12,360 As you drive through the tunnels, there are two big 396 00:21:12,360 --> 00:21:14,360 fractures. Water is pouring through those 397 00:21:14,360 --> 00:21:17,120 fractures, but the fractures only go through the entrance 398 00:21:17,120 --> 00:21:18,840 tunnel. They don't go anywhere near any 399 00:21:18,840 --> 00:21:22,000 of the storage vaults and they're literally building 400 00:21:22,000 --> 00:21:25,400 tunnel after tunnel after tunnel at the moment, ready for when 401 00:21:25,400 --> 00:21:27,880 they're going to put the first spent nuclear fuel. 402 00:21:27,880 --> 00:21:29,800 This is fuel that's come straight from the reactor, not 403 00:21:29,800 --> 00:21:32,840 recycled. This will go into the facility 404 00:21:32,840 --> 00:21:35,520 at some point, we're hoping in the next decade or so. 405 00:21:35,520 --> 00:21:38,360 So that's really exciting that the Finnish facility will be the 406 00:21:38,360 --> 00:21:40,960 first. Other countries are also 407 00:21:40,960 --> 00:21:43,520 planning facilities and they're at various different stages 408 00:21:43,520 --> 00:21:45,800 either in construction or planning. 409 00:21:45,800 --> 00:21:48,680 So Sweden is building their facility in the same rock as the 410 00:21:48,680 --> 00:21:51,480 Finnish one. In Switzerland and France, 411 00:21:51,480 --> 00:21:54,000 they're using clay as a completely different type of 412 00:21:54,000 --> 00:21:57,040 concept where you have super impermeable rock. 413 00:21:57,040 --> 00:21:59,480 It requires different construction techniques because 414 00:21:59,480 --> 00:22:03,000 the the rock's perhaps not quite as strong and other countries 415 00:22:03,000 --> 00:22:06,400 around the world are trying to find a site or they're not 416 00:22:06,400 --> 00:22:09,400 thinking about it yet. The only other one I will raise 417 00:22:09,400 --> 00:22:12,560 is a facility in the US in New Mexico called WIP. 418 00:22:12,560 --> 00:22:16,240 It's the Waste Isolation Pilot Plant and this is a facility 419 00:22:16,240 --> 00:22:18,760 that is underground. It's built in an evaporite 420 00:22:18,800 --> 00:22:22,840 deposit and they've been disposing their some military 421 00:22:22,840 --> 00:22:26,080 waste from the US military program and that's been 422 00:22:26,080 --> 00:22:27,640 operational for a number of years. 423 00:22:27,640 --> 00:22:29,800 And some of you may have heard that there was an accident there 424 00:22:29,800 --> 00:22:32,440 a few years ago and there was a small release of radioactivity. 425 00:22:32,440 --> 00:22:36,960 It's really a good lesson to see how humans aren't infallible in 426 00:22:36,960 --> 00:22:38,800 this situation. The rocks are doing their job 427 00:22:38,800 --> 00:22:40,360 just fine. There's a whole dog, they're 428 00:22:40,360 --> 00:22:43,040 drilling vaults and they're doing everything that they want, 429 00:22:43,040 --> 00:22:45,560 but there have been some human error that led to a mistake 430 00:22:45,560 --> 00:22:47,120 there. So that's something to think 431 00:22:47,120 --> 00:22:48,160 about. We can put our trust in the 432 00:22:48,160 --> 00:22:51,320 rocks, but we can't necessarily put a trust in ourselves. 433 00:22:51,880 --> 00:22:54,400 I presume that nobody really wants this kind of thing in 434 00:22:54,400 --> 00:22:57,160 their backyard, so how do we actually go about selecting a 435 00:22:57,160 --> 00:22:59,040 site? Different countries have done 436 00:22:59,040 --> 00:23:01,280 different things. I can talk about my experience 437 00:23:01,280 --> 00:23:03,800 from the UK perspective. We have a voluntary site 438 00:23:03,800 --> 00:23:06,400 selection process, which is actually also how it was done in 439 00:23:06,400 --> 00:23:10,480 Finland and Sweden and Canada. And So what these countries do 440 00:23:10,480 --> 00:23:13,160 is to find the community who volunteer to have it. 441 00:23:13,160 --> 00:23:16,400 So in the UK process we need two important things. 442 00:23:16,400 --> 00:23:20,720 One is a good host rock, a suitable host rock and a willing 443 00:23:20,720 --> 00:23:22,440 community. If we don't have those two 444 00:23:22,440 --> 00:23:25,200 things, we can't move forward with any particular site. 445 00:23:25,960 --> 00:23:28,800 You might be thinking, well why? Why would the community want to 446 00:23:28,800 --> 00:23:32,160 have a radioactive waste disposal facility near them? 447 00:23:32,520 --> 00:23:35,760 And one of the major incentives is the financial boost that will 448 00:23:35,760 --> 00:23:38,680 come with that. So governments offer the 449 00:23:38,680 --> 00:23:42,720 communities money essentially to support their local community. 450 00:23:42,720 --> 00:23:45,880 And in Finland and Sweden, actually it came down to two 451 00:23:45,880 --> 00:23:48,000 communities and they were fighting over it because they 452 00:23:48,000 --> 00:23:51,800 really wanted that investment. And the area, particularly in 453 00:23:51,800 --> 00:23:55,400 Finland where they have this facility, they get so much money 454 00:23:55,400 --> 00:23:58,560 and taxes from the radioactive waste disposal facility plus 455 00:23:58,560 --> 00:24:00,560 other industry in the area that they've got some of the best 456 00:24:00,560 --> 00:24:02,840 hospitals, the best schools in the country. 457 00:24:02,840 --> 00:24:07,080 So there really are incentives for local communities to have 458 00:24:07,080 --> 00:24:09,360 this disruption. And I think that's one of the 459 00:24:09,360 --> 00:24:12,680 biggest problems that local people find with this facility. 460 00:24:12,680 --> 00:24:14,960 It's not so much about the long term safety because there's a 461 00:24:14,960 --> 00:24:17,640 general trust that if we as scientists say it's going to be 462 00:24:17,640 --> 00:24:20,640 safe, then OK, all right, Generally it will be safe. 463 00:24:20,640 --> 00:24:23,960 What's more of concern is the day-to-day disruption, digging 464 00:24:23,960 --> 00:24:26,520 all of that rock out from under the ground and having all the 465 00:24:26,520 --> 00:24:28,680 trucks going by and all this kind of stuff. 466 00:24:28,960 --> 00:24:31,480 That's more, I think, what people are concerned about. 467 00:24:32,160 --> 00:24:35,520 So we're really talking about centralised facilities at all 468 00:24:36,000 --> 00:24:39,720 provide enough space for the entire radioactive waste of a 469 00:24:39,720 --> 00:24:42,040 given country with all that disruption. 470 00:24:42,040 --> 00:24:45,360 So roughly what kind of volumes of waste are we talking about? 471 00:24:45,720 --> 00:24:47,680 I can talk about the UK perspective because that's what 472 00:24:47,680 --> 00:24:52,160 I really know. The UK has a volume of 750,000 473 00:24:52,160 --> 00:24:56,120 cubic metres of waste and that's a difficult volume to think of. 474 00:24:56,120 --> 00:24:59,600 So we tend to think of it in terms of the volume of Wembley 475 00:24:59,600 --> 00:25:02,120 Stadium, so the home of English football, OK. 476 00:25:02,840 --> 00:25:07,160 If you were to fill Wembley Stadium, about 2/3 full, that's 477 00:25:07,160 --> 00:25:09,840 about the volume of waste that we have now the area 478 00:25:09,840 --> 00:25:13,120 underground, it's difficult to think of what that translates 479 00:25:13,120 --> 00:25:16,520 into in terms of a cubic meter volume of rock that has to be 480 00:25:16,520 --> 00:25:18,520 excavated. The way that the Waste 481 00:25:18,520 --> 00:25:21,240 management organization thinks about it is actually in square 482 00:25:21,240 --> 00:25:24,080 footage underground. We're thinking about an area 483 00:25:24,080 --> 00:25:26,880 underground with around 26 square kilometres. 484 00:25:26,880 --> 00:25:30,320 So it's really like the size of a large town Underground is what 485 00:25:30,320 --> 00:25:32,560 we're going to be building. Wow, that's enormous. 486 00:25:32,680 --> 00:25:34,720 It is quite huge. It's important to say that the 487 00:25:34,720 --> 00:25:36,440 surface footprint will be a lot smaller. 488 00:25:36,440 --> 00:25:39,040 So the surface footprint will have probably the waste being 489 00:25:39,040 --> 00:25:42,120 delivered on a train or by boat. Potentially, depending on where 490 00:25:42,120 --> 00:25:45,320 it's located, the waste will be offloaded and then sent on. 491 00:25:45,520 --> 00:25:48,160 Probably something like a railway down in into the 492 00:25:48,160 --> 00:25:51,040 facility so that you can think of a bit more like a kind of 493 00:25:51,040 --> 00:25:54,280 football pitch size. But underground, the extent is 494 00:25:54,320 --> 00:25:56,840 absolutely vast. That's a huge amount of rock 495 00:25:56,840 --> 00:25:59,920 that's going to be excavated to host all of that waste. 496 00:26:00,520 --> 00:26:04,080 We're talking about periods of time here that are so much 497 00:26:04,080 --> 00:26:07,520 longer than any human organization or human structure 498 00:26:07,520 --> 00:26:10,960 has existed. Do we even know how to think 499 00:26:10,960 --> 00:26:13,320 about planning for millennia into the future it? 500 00:26:13,800 --> 00:26:17,320 Is a really good question and it's very difficult to foresee 501 00:26:17,320 --> 00:26:20,480 those really long time scales. What I would do is flip it on 502 00:26:20,480 --> 00:26:24,400 its head and say well how good are we going to be at actually 503 00:26:24,400 --> 00:26:29,080 managing this waste above ground for the next 50 years, 100 504 00:26:29,080 --> 00:26:32,200 years, these time scales we can look to and that's where we are 505 00:26:32,200 --> 00:26:33,760 at the moment. We have the waste in these above 506 00:26:33,760 --> 00:26:36,440 ground facilities. Can we guarantee that they're 507 00:26:36,440 --> 00:26:39,120 going to be safe over the course of 100 years? 508 00:26:39,240 --> 00:26:41,160 Probably. I mean probably our society is 509 00:26:41,160 --> 00:26:45,080 going to be more or less how it is now in 100 years time better. 510 00:26:45,080 --> 00:26:48,280 I hope you're thinking with my optimist hat on, but over 500 511 00:26:48,280 --> 00:26:52,120 years, can we guarantee that the people are going to be 500 years 512 00:26:52,240 --> 00:26:54,880 hence from now? Will they be able to look after 513 00:26:54,880 --> 00:26:56,760 the waste in the same way? Will they have the same 514 00:26:56,760 --> 00:26:58,680 technology? Will we have the same kind of 515 00:26:58,680 --> 00:27:01,120 stability? So I think the question is, 516 00:27:02,080 --> 00:27:05,320 isn't it better to try and isolate it away from future 517 00:27:05,320 --> 00:27:08,560 populations over time scales that we can't imagine, then 518 00:27:08,560 --> 00:27:11,360 leave it where it is for now on time scales that we can. 519 00:27:11,480 --> 00:27:14,480 So while it is very difficult to think about those long time 520 00:27:14,480 --> 00:27:17,200 scales, I think the alternative is worse. 521 00:27:17,840 --> 00:27:22,760 One other thing to say is that on a geological time scale, what 522 00:27:22,760 --> 00:27:24,440 we're talking about here isn't very long. 523 00:27:25,000 --> 00:27:28,440 You and I, We think of a million years as the blink of an eye in 524 00:27:28,440 --> 00:27:29,840 terms of a geological time scale. 525 00:27:29,840 --> 00:27:33,000 But for these materials, for engineers, for people who think 526 00:27:33,000 --> 00:27:36,880 about corrosion of the container materials, what's going to sit 527 00:27:36,880 --> 00:27:39,880 around the container? The waste itself, a million 528 00:27:39,880 --> 00:27:42,600 years is a tremendously long amount of time. 529 00:27:43,080 --> 00:27:46,640 We can only do as best as we can as scientists in the lab to be 530 00:27:46,640 --> 00:27:49,680 able to try and predict how those materials are going to 531 00:27:49,680 --> 00:27:52,080 behave over a long time period. I would love to have a time 532 00:27:52,080 --> 00:27:55,040 machine and to be able to Fast forward a million years to say 533 00:27:55,040 --> 00:27:57,480 yes, do you know what that geological disposal facility 534 00:27:57,480 --> 00:27:59,520 worked? It did what it needed to do, but 535 00:27:59,760 --> 00:28:01,560 we don't. So we have to try and do what we 536 00:28:01,560 --> 00:28:03,960 can. But do we worry about potential 537 00:28:03,960 --> 00:28:06,520 bad actors having access to this? 538 00:28:06,520 --> 00:28:11,880 Or are there much easier ways to wreak nuclear havoc than picking 539 00:28:11,880 --> 00:28:15,120 up some ancient radioactive waste facility? 540 00:28:15,560 --> 00:28:19,680 Well, I think the idea is that once the waste is disposed and 541 00:28:19,680 --> 00:28:23,120 countries are are thinking about this now, that when it's 542 00:28:23,120 --> 00:28:27,320 disposed underground and it's all sealed off and closed, that 543 00:28:27,440 --> 00:28:29,680 potential future bad actors won't know it's there. 544 00:28:29,680 --> 00:28:32,360 The idea is that we bury it and we completely forget. 545 00:28:32,560 --> 00:28:36,040 And this is, for example what Finland have decided to do, that 546 00:28:36,040 --> 00:28:40,160 there is nothing that points to future populations to say, hey 547 00:28:40,160 --> 00:28:42,360 guys, there's this stuff here that you might want to get out 548 00:28:42,360 --> 00:28:44,080 of the ground. It's better that it's completely 549 00:28:44,080 --> 00:28:46,280 forgotten. That's not the opinion of 550 00:28:46,280 --> 00:28:48,080 everybody. Some people think that it should 551 00:28:48,080 --> 00:28:51,680 be marked and there are some wonderful plans for putting up 552 00:28:51,680 --> 00:28:55,440 really scary statues to make it look like a very uninviting 553 00:28:55,440 --> 00:28:58,600 place because we might not be able to rely upon language being 554 00:28:58,600 --> 00:29:00,960 the same over the million year time scale. 555 00:29:01,400 --> 00:29:05,160 There are other slightly more crazy ideas about trying to this 556 00:29:05,160 --> 00:29:06,800 is genuine. I don't know how it would ever 557 00:29:06,800 --> 00:29:10,400 work but genetically engineer cats so that when they came into 558 00:29:10,440 --> 00:29:14,120 a particular perimeter near the geological disposal facility, 559 00:29:14,120 --> 00:29:16,680 their fur would change colour. I mean you can think of all of 560 00:29:16,680 --> 00:29:19,040 the weird and the wonderful things that you want to people 561 00:29:19,040 --> 00:29:21,400 are thinking about this. How do we mark that facility in 562 00:29:21,400 --> 00:29:24,120 the future? But to make sure that it's 563 00:29:24,120 --> 00:29:28,160 completely forgotten is probably the goal, so that waste can 564 00:29:28,160 --> 00:29:32,320 safely radioactively decay completely undisturbed for the 565 00:29:32,320 --> 00:29:35,200 million years that's required. What are you working on at the 566 00:29:35,200 --> 00:29:38,400 moment? So aside from the question about 567 00:29:38,400 --> 00:29:42,040 plutonium, there's other sets of projects I like to call turning 568 00:29:42,040 --> 00:29:45,520 radioactive waste into rocks. So this is the idea around using 569 00:29:45,520 --> 00:29:48,920 the titanate minerals as a template for future waste types. 570 00:29:49,400 --> 00:29:53,440 We also do a lot of work trying to develop new types of glass 571 00:29:53,440 --> 00:29:57,360 materials for types of waste that don't currently have a 572 00:29:57,400 --> 00:30:01,080 disposal route and they need to be transformed in some way into 573 00:30:01,080 --> 00:30:03,360 a safer material. And actually a glass is a 574 00:30:03,360 --> 00:30:05,240 brilliant materials as we've discussed. 575 00:30:05,560 --> 00:30:09,000 And so we're using what we know about the earth, the deep earth 576 00:30:09,000 --> 00:30:12,840 and how rocks are melted and we take all that knowledge and try 577 00:30:12,840 --> 00:30:16,120 and translate it into developing new types of glass materials 578 00:30:16,120 --> 00:30:19,240 essentially. And when those glass materials 579 00:30:19,240 --> 00:30:23,000 are developed we're also very much interested in how quickly 580 00:30:23,000 --> 00:30:25,320 they dissolve. So we do a lot of experiments to 581 00:30:25,320 --> 00:30:29,400 try and to understand the rate at which the radio nuclides that 582 00:30:29,400 --> 00:30:32,080 we're trying to lock up inside their structure, how quickly 583 00:30:32,080 --> 00:30:36,120 they might be released as well. Clark Hawkill, thank you very 584 00:30:36,120 --> 00:30:38,040 much. Thank you very much. 585 00:30:39,440 --> 00:30:42,120 To see pictures and illustrations that support this 586 00:30:42,120 --> 00:30:47,680 podcast, go to geologybytes.com, where you'll also find 587 00:30:47,680 --> 00:30:52,040 transcripts and a subject matter index of all the episodes there. 588 00:30:52,040 --> 00:30:55,640 You can also give me feedback, which I welcome, as well as sign 589 00:30:55,640 --> 00:30:58,080 up to get my emails about new episodes.