Adonis Diaries

Archive for July 12th, 2015

Small nuclear fission reactors? How small, how radical?

Well, I have a big announcement to make today, and I’m really excited about this. And this may be a little bit of a surprise to many of you who know my research and what I’ve done well.

I’ve really tried to solve some big problems: counterterrorism, nuclear terrorism, and health care and diagnosing and treating cancer, but I started thinking about all these problems, and I realized that the really biggest problem we face, what all these other problems come down to, is energy, is electricity, the flow of electrons.  (Need a huge explanation)

And I decided that I was going to set out to try to solve this problem.

And this probably is not what you’re expecting. You’re probably expecting me to come up here and talk about fusion, because that’s what I’ve done most of my life.

But this is actually a talk about fission.

It’s about perfecting something old, and bringing something old into the 21st century.

Let’s talk a little bit about how nuclear fission works. In a nuclear power plant, you have a big pot of water that’s under high pressure, and you have some fuel rods, and these fuel rods are encased in zirconium, and they’re little pellets of uranium dioxide fuel, and a fission reaction is controlled and maintained at a proper level, and that reaction heats up water, the water turns to steam, steam turns the turbine, and you produce electricity from it.

This is the same way we’ve been producing electricity, the steam turbine idea, for 100 years, and nuclear was a really big advancement in a way to heat the water, but you still boil water and that turns to steam and turns the turbine.

And I thought, you know, is this the best way to do it?

Is fission kind of played out, or is there something left to innovate here?

And I realized that I had hit upon something that I think has this huge potential to change the world. And this is what it is.

 This is a small modular reactor. So it’s not as big as the reactor you see in the diagram here.

This is between 50 and 100 megawatts. But that’s a ton of power.   About 25,000 to 100,000 homes could run off that power.

Now the really interesting thing about these reactors is they’re built in a factory.  (Are the other reactors built onsite?)

So they’re modular reactors that are built essentially on an assembly line, and they’re trucked anywhere in the world, you plop them down, and they produce electricity. This region right here is the reactor.

And this is buried below ground, which is really important. (The other reactors are not buried the same way?)

For someone who’s done a lot of counterterrorism work, I can’t extol to you how great having something buried below the ground is for proliferation and security concerns.

3:09 And inside this reactor is a molten salt, so anybody who’s a fan of thorium, they’re going to be really excited about this, because these reactors happen to be really good at breeding and burning the thorium fuel cycle, uranium-233.

 But I’m not really concerned about the fuel.

You can run these off — they’re really hungry, they really like down-blended weapons pits, so that’s highly enriched uranium and weapons-grade plutonium that’s been down-blended.

It’s made into a grade where it’s not usable for a nuclear weapon, but they love this stuff.

And we have a lot of it sitting around, because this is a big problem.

You know, in the Cold War, we built up this huge arsenal of nuclear weapons, and that was great, and we don’t need them anymore, and what are we doing with all the waste, essentially?

What are we doing with all the pits of those nuclear weapons? Well, we’re securing them, and it would be great if we could burn them, eat them up, and this reactor loves this stuff.

So it’s a molten salt reactor. It has a core, and it has a heat exchanger from the hot salt, the radioactive salt, to a cold salt which isn’t radioactive.

It’s still thermally hot but it’s not radioactive.

And then that’s a heat exchanger to what makes this design really interesting, and that’s a heat exchanger to a gas.

So going back to what I was saying before about all power being produced — well, other than photovoltaic — being produced by this boiling of steam and turning a turbine, that’s actually not that efficient, and in fact, in a nuclear power plant like this, it’s only roughly 30 to 35 percent efficient.

That’s how much thermal energy the reactor’s putting out to how much electricity it’s producing. And the reason the efficiencies are so low is these reactors operate at pretty low temperature. They operate anywhere from maybe 200 to 300 degrees Celsius.

And these smaller reactors run at 600 to 700 degrees Celsius, which means the higher the temperature you go to, thermodynamics tells you that you will have higher efficiencies. And this reactor doesn’t use water. It uses gas, so supercritical CO2 or helium, and that goes into a turbine, and this is called the Brayton cycle.

This is the thermodynamic cycle that produces electricity, and this makes this almost  between 45 and 50 percent efficiency.

And I’m really excited about this, because it’s a very compact core. Molten salt reactors are very compact by nature, but what’s also great is you get a lot more electricity out for how much uranium you’re fissioning, not to mention the fact that these burn up. Their burn-up is much higher. So for a given amount of fuel you put in the reactor, a lot more of it’s being used.

5:52 And the problem with a traditional nuclear power plant like this is, you’ve got these rods that are clad in zirconium, and inside them are uranium dioxide fuel pellets.

Well, uranium dioxide’s a ceramic, and ceramic doesn’t like releasing what’s inside of it.

So you have what’s called the xenon pit, and so some of these fission products love neutrons. They love the neutrons that are going on and helping this reaction take place. And they eat them up, which means that, combined with the fact that the cladding doesn’t last very long, you can only run one of these reactors for roughly, say, 18 months without refueling it.

So these small reactors run for 30 years without refueling, which is, in my opinion, very, very amazing, because it means it’s a sealed system. No refueling means you can seal them up and they’re not going to be a proliferation risk, and they’re not going to have either nuclear material or radiological material proliferated from their cores.

6:49 But let’s go back to safety, because everybody after Fukushima had to reassess the safety of nuclear, and one of the things when I set out to design a power reactor was it had to be passively and intrinsically safe, and I’m really excited about this reactor for essentially two reasons.

1.  One, it doesn’t operate at high pressure. So traditional reactors like a pressurized water reactor or boiling water reactor, they’re very, very hot water at very high pressures, and this means, essentially, in the event of an accident, if you had any kind of breach of this stainless steel pressure vessel, the coolant would leave the core.

These small reactors operate at essentially atmospheric pressure, so there’s no inclination for the fission products to leave the reactor in the event of an accident.

2. Also, they operate at high temperatures, and the fuel is molten, so they can’t melt down, but in the event that the reactor ever went out of tolerances, or you lost off-site power in the case of something like Fukushima, there’s a dump tank.

Because your fuel is liquid, and it’s combined with your coolant, you could actually just drain the core into what’s called a sub-critical setting, basically a tank underneath the reactor that has some neutrons absorbers. And this is really important, because the reaction stops.

In the traditional kind of reactor, you can’t do that. The fuel, like I said, is ceramic inside zirconium fuel rods, and in the event of an accident in one of these type of reactors, Fukushima and Three Mile Island — looking back at Three Mile Island, we didn’t really see this for a while — but these zirconium claddings on these fuel rods, what happens is, when they see high pressure water, steam, in an oxidizing environment, they’ll actually produce hydrogen, and that hydrogen has this explosive capability to release fission products.

The core of this small reactor, since it’s not under pressure and it doesn’t have this chemical reactivity, means that there’s no inclination for the fission products to leave this reactor.

So even in the event of an accident the reactor may be toast, which is, you know, sorry for the power company, but we’re not going to contaminate large quantities of land.

So I really think that in the, say, 20 years it’s going to take us to get fusion and make fusion a reality, this could be the source of energy that provides carbon-free electricity. Carbon-free electricity.

9:14 And it’s an amazing technology because not only does it combat climate change, but it’s an innovation. It’s a way to bring power to the developing world, because it’s produced in a factory and it’s cheap. You can put them anywhere in the world you want to.

 And maybe something else. As a kid, I was obsessed with space. Well, I was obsessed with nuclear science too, to a point, but before that I was obsessed with space, and I was really excited about being an astronaut and designing rockets, which was something that was always exciting to me.

But I think I get to come back to this, because imagine having a compact reactor in a rocket that produces 50 to 100 megawatts. That is the rocket designer’s dream.

That’s someone who is designing a habitat on another planet’s dream. Not only do you have 50 to 100 megawatts to power whatever you want to provide propulsion to get you there, but you have power once you get there.

You know, rocket designers who use solar panels or fuel cells, I mean a few watts or kilowatts — wow, that’s a lot of power. I mean, now we’re talking about 100 megawatts. That’s a ton of power. That could power a Martian community. That could power a rocket there. And so I hope that maybe I’ll have an opportunity to kind of explore my rocketry passion at the same time that I explore my nuclear passion.

And people say, “Oh, well, you’ve launched this thing, and it’s radioactive, into space, and what about accidents?”

But we launch plutonium batteries all the time. Everybody was really excited about Curiosity, and that had this big plutonium battery on board that has plutonium-238, which actually has a higher specific activity than the low-enriched uranium fuel of these molten salt reactors, which means that the effects would be negligible, because you launch it cold, and when it gets into space is where you actually activate this reactor.

 I’m really excited. I think that I’ve designed this reactor here that can be an innovative source of energy, provide power for all kinds of neat scientific applications, and I’m really prepared to do this.

I graduated high school in May and I decided that I was going to start up a company to commercialize these technologies that I’ve developed, these revolutionary detectors for scanning cargo containers and these systems to produce medical isotopes, but I want to do this, and I’ve slowly been building up a team of some of the most incredible people I’ve ever had the chance to work with, and I’m really prepared to make this a reality.

And I think that looking at the technology, this will be cheaper than or the same price as natural gas, and you don’t have to refuel it for 30 years, which is an advantage for the developing world.

12:02 And I’ll just say one more maybe philosophical thing to end with, which is weird for a scientist. But I think there’s something really poetic about using nuclear power to propel us to the stars, because the stars are giant fusion reactors. They’re giant nuclear cauldrons in the sky.

The energy that I’m able to talk to you today, while it was converted to chemical energy in my food, originally came from a nuclear reaction, and so there’s something poetic about, in my opinion, perfecting nuclear fission and using it as a future source of innovative energy.

  • My radical plan for small nuclear fission reactors
    Taylor Wilson was 14 when he built a nuclear fusion reactor in his parents’ garage. Now 19, he returns to the TED stage to present a new take on an old topic: fission. Wilson, who has won backing to create a company to realize his vision, explains why he’s so excited about his innovative design for small modular fission reactors — and why it could be the next big step in solving the global energy crisis.
    TED · 794 Shares · Mar 6, 2014

Sex-Ed in Lebanese Schools: Let’s talk

Apparently, the author of this article is Loulwa Soweidlous94@bu.edu (Got this info from her comment)

Lebanon has been described as one of the most liberal Arab countries, but traces (traces? How funny) of conservatism are evident in the fact that speaking about anything remotely related to sex is labeled as shameful, at times even in clinical settings with a physician.

As such, the simple fact that sexual education has the word, “sex” in it has landed it on top of a long list of taboos.

So let’s talk about sex, or more specifically, let’s talk about the lack of sex-ed in Lebanese schools, and why that needs to change.

One of the common misconceptions about sex-ed is that it is solely and primarily concerned with the act of sexual intercourse.

But sex-ed is more than merely a crash-course in coitus, with gynecologist and public health advocate Faysal El-Kak noting that

“sexual education is about developing the right attitudes, promoting an understanding of sexual health, rights and consent, and discussing the value of sex in people’s lives in terms of emotional expression and experience.”

Diana Abou Abbas and Cynthia El Khoury, the manager and program coordinator of the Beirut-based sexual health clinic Marsa, also stress that children need to be educated about prevention methods and treatment options for sexually-transmitted infections so that they will not be at a greater risk of contracting them when they do become sexually active.

Furthermore, they need to be exposed to issues of bodily rights and consent. Abou Abbas and El Khoury note that many clients who approach Marsa report a forced first sexual encounter.

And if teachers and parents are worried about inadvertently encouraging sex through sex-ed discussions, El-Kak notes that

evidence indicates that talking to youth or adolescents about sex actually delays the age of engagement in first sexual activity.”

What sex-ed does increase is the likelihood of safe sex in the future, thereby decreasing the chances of STI transmission and unwanted pregnancies.

Sex-ed also helps children learn about the bodily changes that they are experiencing at puberty in an informative rather than intimidating manner.

For example, Marsa recently released the witty, child-friendly video “Leila the Spy,” which “busts the myths around menstruation.”

Another issue is that, try as parents might, there is little they can do to stop their children from learning about sex one way or another.

The Lebanese blogger Leblad recently recounted his first experience as a peer-educator, stepping into a classroom prepared to lead an administration-approved, puberty-based discussion with students, only to find that elementary-school kids had questions revolving around a lot more than just puberty.

“A common argument that I hear when I tell people that I am a peer educator is that kids are not mature or ready to hear such things,” says Leblad, but notes that they already are being exposed to sexual ideas because of unlimited access to the internet.

Existing educational systems should therefore be encouraged to adopt sex-ed because “we need to get that information to them first so they know the facts.”

Farah Mouhanna, a current biology teacher who completed her thesis on factors associated with attitudes towards reproductive health education (the more societally-acceptable term for sex-ed) in middle-school students in Lebanon, notes that many of the students she interviewed had received information about sex from pornographic videos, other sources from the internet, or friends who were as misinformed as they were.

It’s hard for them to have access to reliable sources about sex because it’s taboo, so parents and schools are not discussing it and neither is the media,” says Mouhanna.

“So you can’t control the sources that they are accessing. It’s a cycle,” she continues, “don’t educate them, and they can’t have the taboo removed, and unless you remove the taboo, you can’t educate them, and we need to break the cycle somehow.”

And according to a 2011 article, it seems that we were taking a cautious step in the right direction to break the vicious cycle, with the Center for Educational Research and Development, collaborating with the UNPFA to develop sex-ed-inclusive curricula for Lebanese schools.

But the process is slow, as the curricula have yet to be implemented years later.

Until sexual education becomes part of the lesson plan, the NGO LeMSIC-SCORA offers peer-education sessions to students and provides a safe environment for children to ask whatever questions they may have.

Furthermore, Marsa offers discounted and confidential medical consultations, laboratory screenings and tests for STIs, as well as psychosocial support for issues under the scope of sexual health, orientation, gender and violence.

One of the common misconceptions about sex-ed is that it is solely and primarily concerned with the act of sexual intercourse.

But sex-ed is more than merely a crash-course on coitus…

Let’s talk about sex, or more specifically, let’s talk about the lack of sex-ed in Lebanese schools, and why that needs to change.
beirut.com

adonis49

adonis49

adonis49

July 2015
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