字幕表 動画を再生する 英語字幕をプリント Pat, we have a reactor trip on Unit 5. Containment is isolated. Demon water is isolated. CVCS is isolated. DHR is in service. And pressurizer heater trips has occurred. All safety functions are green. Understand. We've got a reactor trip on Unit 5 and all safety functions are green. That's correct. Ryan, can you take over the plant response to Unit 5? You're in the middle of a simulated reactor trip. Something happened that’s causing an emergency shutdown. Ryan I have acknowledged the alarms. Understand that you've acknowledged the alarms. This demonstration took place at NuScale, a next generation nuclear power company that wants to operate a string of up to 12 small reactors from a single control room. And their new model might just revive the nuclear power industry. When you think nuclear, you might imagine a plant like this: enormous cooling towers, generators, steam billowing out the top. They’ve been a part of our energy mix for decades all working to harness the power of splitting uranium atoms. Or in other words: Nuclear power, to put it simply, is the most complicated way to boil water. What you’re trying to do is to take the energy that’s produced by splitting uranium nuclei and convert it into steam. That steam then goes to a turbine which turns a shaft which then turns a generator to produce electricity.When the splitting happens, it produces radioactive materials. Much of the nuclear plant is really focused on trying to make sure that these radioactive materials never escape out into the biosphere. There are hundreds of reactors boiling water across the globe, and you might actually be living near one. But the nuclear industry today is experiencing some major shifts. The 3 Mile Island and Fukushima disasters prompted countries like Germany and Switzerland to dismantle their nuclear power infrastructure. Despite efforts from Russia and China to kick-start new projects, global construction is currently on a down-swing. Here in the U.S., aging reactors are retiring, and Westinghouse, one of the biggest names in nuclear, recently filed for bankruptcy. The argument the nuclear industry used to make is that even though nuclear power plants are expensive to build they are cheap to operate and therefore profitable. That equation has changed in the last seven or eight years. There have been a combination of two things that have been happening. One is that as these plants’ age, the cost of keeping them operational has been increasing because simultaneously and more importantly, the cost of alternative sources of energy has declined dramatically. The second thing I would say is that, the argument used to be, oh, we’ve learned a lot from mistakes in the past. We will be able to lower the cost and how fast these reactors are built, and that has not happened. The South Carolina project was so expensive, the company pulled out of it after spending about $9 billion, that's essentially been abandoned. The Georgia plant is now running at around $25 to $27 billion, compared to a few billion dollars that was the initial expectation. I think the result of that is nobody in their right mind should be thinking about building another large nuclear plant in the country. It’s a tough situation, especially with reports of rising CO2 emissions and calls for alternatives to meet climate goals. And that’s where these next generation reactors enter the conversation for multiple countries. Hoping to solve the problems of cost and scale, this new nuclear fleet are called SMRs or Small Modular Reactors. Small in this context just means it’s producing less than 300 megawatts of electricity. The plants that were being built in South Carolina, the ones being built in Georgia generate about 1,100 megawatts of electricity. Modular means that you can make these things in a factory. You're manufacturing all your high quality components in parallel you're doing all your civil construction on site. You’re making the pool, you’re building the building. And then when the buildings are done, you transport the modules to the site and you install them. Beyond these two there’s really nothing that constrains you about the design of the reactor. There are literally dozens and dozens of SMR designs. Portable nuclear power has a back to the future feel to it. Pursued since the Cold War, several designs have found their way inside nuclear submarines and university labs. After decades of attempts, SMRs haven't been the mainstream source of power for local communities just yet, but that might change with NuScale. This all started with a project that was funded by the Department of Energy back in 2000. We were working with the Idaho National Laboratory at the time and we came up with this concept for something small that could be built in a factory. So inside our modules, we start off with the containment vessel. It's about 76 feet long and 15 feet in diameter, it’s big cylinder. Inside that containment vessel the reactor vessel houses the fuel, the steam generator. It's a helical coil steam generator. Everything you need for power to produce steam is inside that one little vessel. Now the containment and the reactor vessel sit underwater below ground. And you can add on, two, three up to 12 modules in a single pool. So it's scalable because you don't have to add them all at once, you can do them in increments. Each module will produce about 60 megawatts electric. If you think about homes, it's somewhere around fifty thousand homes would be powered by one module. There aren't any additional cooling pumps or generators that could fail in an emergency, a lesson learned from previous disasters. Because a key element NuScale really emphasized with us, is safety. Passive safety really describes the ability to perform a safety function without power. For our design, the reactors will safely shut themselves down without any operator action or computer action, without any AC or DC power, and they'll remain cooled for an indefinite period of time, without the need to add water. When you lose power, the control rods actually fall into the reactor vessel into the core and they're held up normally by electromagnets. So you lose power, they disengage and they fall. So you go from two hundred megawatts thermal to about 10 or 11 megawatts in a second or so. If you look at the control room here, you'll see that a lot of things that we do really don't require operator action at all. All the procedures come up on the screens themselves and they help you execute the procedures, and they’ll help correct you if you make a mistake it's a smart control room. Which all seems quite miraculous — to have a nuclear control room run mostly on its own. NuScale’s timeline has more tick marks ahead. Their plant operations are still just on paper or at prototype stage. They’re aiming to turn on their first commercial plant near the Idaho National Laboratory by 2026, which brings the project full circle. We finished our design certification application. It's a pretty comprehensive checklist, so application alone was 12,000 pages. We're on track to get this design certified with the final safety evaluation report coming out in September of 2020. So, that’s the target. And within their application, NuScale is asking the U.S. Nuclear Regulatory Commission for a different kind of zoning boundary. In the United States, there's a requirement that you have an emergency planning zone around your plant and that zone is a 10 mile radius. The reason we can request a smaller emergency planning zone is because of the very high level of safety that we offer. If we go back to their animation, the reactor’s sitting in a pool that’s below ground with a biological shield on top of that and in a seismic category which is earthquake proof, hurricane proof type building. In our analysis, we show that we don't exceed regulatory doses under the worst case accident conditions at the site boundary so that changes the game significantly in that we can be in closer proximity to population centers. If you have an SMR and it has an accident, it would have less amount of radioactive material to disperse it would have less energy to disperse. These are laws of physics in certain complicated circumstances that are hard to predict in advance. If you think about the kind of accidents we’ve seen in the past it is almost always been a bunch of circumstances which nobody had envisioned. If you’re thinking about the community and you go and say, “Look, we want to build this nuclear plant near you but there is a small chance that something might go wrong it’s quite possible you might have to leave your house and never come back because it’s going to be contaminated with radioactivity. How do you feel about it?” Quite a few people would say, “No, I don’t think I would want that. Despite this risk potential, the hundreds of reactors operating worldwide have had a pretty safe track record, and overall have caused less loss of life than coal or natural gas. The design & safety of future reactors in the US are assessed by the Nuclear Regulatory Commission. But there’s some context to this agency that bears keeping in mind: The NRC’s fortunes, in a sense, depend on the industry that it is regulating. If the nuclear industry were to essentially shrink and vanish, the NRC would essentially have to vanish too. The NRC and NuScale have been talking to each other for years now and trying to say, “Okay, here's our rules. Here's how you interpret these rules. Here's how we can modify our design. All of which does not seem to me to be a thoroughly independent process. There’s been a reported history of regulatory capture in the nuclear industry, but it shouldn’t come as any surprise. What entity other than a state government can take on the capital and risk associated with investing in nuclear? Government funding does play an important part. The question, of course, to ask is whether the government should be spending its money on this pursuit. Of course, that’s a different question. The new nuclear power movement is appealing to governments who see the potential: One module could produce 60 million gallons of clean desalinated water per day. So a 12 pack would be enough to provide all the water needs for a city the size of Cape Town South Africa. On the flip side, SMRs could exacerbate pre-existing geopolitical tensions. China has said they are also developing SMRs. The first place that they want to deploy are on these deserted islands, in the South China Sea that are in disputes. If you’re concerned about proliferation, then SMRs are not small in any meaningful sense. With these forces ahead, eyes will be on NuScale as they work to reshape the industry and roll out what they are betting on to be a smart, scalable model of nuclear power. Their hope is that a safer design, an automated control room, and other key features will overcome the hurdles that caused previous ventures to fail. However, there are still open questions over nuclear waste, protecting against proliferation, and how a truly passive nuclear plant operates in real time. But until this model is put to the test, the ultimate question for nuclear - of whether smaller really is better - remains an open one.