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Making Nuclear Energy Smaller, Cheaper And Safer

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Re: Making Nuclear Energy Smaller, Cheaper And Safer

#61

Post by jcranmer »

petschge wrote: post #55
jcranmer wrote: post #39

Earlier quoted context omitted.

What if a dam explodes? More people have died due to dam failures (both intentional and accidental) than have died to nuclear power, but there is nowhere near the freaking out over the safety of dams compared to nuclear power. For comparison, the Banqiao Dam failure (the largest dam failure in history) killed as many people as the sum total of every nuclear power plant failure and every atomic bomb ever used, combine…

While dam break cost lives, there is crucial differences that are never mentioned by the pro-nuclear crowd on HN. 1.) Dam breaks devastate much smaller areas. So even if the human toll is the same, the amount of infrastructure lost is smaller. 2.) The area is unlivable (or even inaccessible) for a much smaller duration of month instead of millenia. Maybe land lost "forever" (on the timescale of individual human lives…

Chernobyl's exclusion zone was ~1000 mi^2, consisting of ~120,000 people. The Oroville dam evacuation zone is ~250mi^2 encompassing ~180,000 people. Floods are no laughing matters; the Chinese decision to break the levees of the Yellow River during the Second Sino-Japanese War is credited with killing 400,000 people or so and rendering millions homeless, and the land was unusable for the better part of a decade, not "a month."

> 2.) The area is unlivable (or even inaccessible) for a much smaller duration of month instead of millenia.

Millennia of uninhabitability is anti-nuclear propaganda. Most of the zone will be reinhabitable within a century of the accident, and much of it is already inhabitable again but still excluded out of safety margin concerns.

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#62

Post by i_am_proteus »

jabl wrote: post #46
nine_k wrote: post #44

Earlier quoted context omitted.

I also wonder if converting old coal-fired plants is possible. If the turbines, generators, and the power distribution stuff is in place and in a good shape, maybe setting up an alternative source of steam could be more economical than building the whole thing from scratch.

Typical coal plants use superheated steam at around 540C and turbines designed for that, whereas LWRs produce wet steam at 300C, so no. High-temperature reactors can produce superheated steam, but then it's not a LWR and you give up on all the knowhow how to run those. The Chinese are planning to deploy gas cooled pebble bed reactors which could replace the coal furnace at existing plants (HTR-PM).

Alt. take: one could not reuse the turbines, at least not efficiently. One might be able to reuse other parts of the steam/condensate/feed systems. The electrical systems could largely be reused.

I doubt that reusing anything other than the power distribution and cooling loops would be economical.

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#63

Post by beders »

acidburnNSA wrote: post #20
benj111 wrote: post #9

Earlier quoted context omitted.

"Having passive decay heat removal usually decreases the probability of core damage by about 100x." 100x isn't 100% though. 100 of these small reactors has the same risk as one large reactor. Perhaps higher, because like you, everyone goes around saying the risk has been designed out. Though obviously one small reactor going boom is preferable to a big one doing the same.

100% safe is never the metric. Nothing is 100% safe. Every form of energy generation has risks that have to balance the good the energy source brings. Nuclear is nearly unique in that it can produce carbon-free energy (unlike fossil and biomass), continuously for 2 years on end between reloads (unlike wind/solar/coal), and it can be deployed in a wide variety of geographic locations (unlike hydro and geothermal). The…

A 1% failure rate is not acceptable.

Nice try downplaying the actual consequences of a reactor incident like Chernobyl.

Do I have to mention radioactive boars roaming in Bavarian forests again?

The billions in costs to an economy?

The only part I agree with you is that coal is a not an acceptable way to generate power.

There's now sufficiently cheap power generators that don't devastate whole areas for centuries to come. Let's use those instead of this old nuclear tech.

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#65

Post by Animats »

"My concern about NuScale is that they believe so deeply that their reactor is safe and doesn't need to meet the same criteria as the larger reactors, that it's pushing for lots of exemptions and exceptions," says Edwin Lyman, acting director of the Nuclear Safety Project at the Union of Concerned Scientists.

Here's a picture of the setup.[1] The reactors all share the same pool. The pool is big enough to absorb the heat in an emergency, and passive heat transfer from reactor to pool is high due to a smaller reactor size, and all this passively prevents a meltdown.

So they have one class of failure covered. But that's not the only possible failure. Leaks into the pool become a big problem, because one reactor can contaminate the pool and all the other reactors. Three Mile Island had a valve failure and contaminated the containment vessel. That was expensive to clean up, and made the reactor useless, but didn't cause trouble outside the plant. A plumbing leak with NuScale could take down all the reactors.

[1] https://www.world-nuclear-news.org/Articles/NuScale-SMR-ente...

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#66

Post by Retric »

j9461701 wrote: post #23
vidanay wrote: post #15

I have a hard time accepting their premise that they are designing for "cheaper" based on that artists rendering (which I assume is based on some real design elements). Curvy roofed buildings and arced cooling ponds are not at all the most cost effective construction methods. I want truly cheap nuclear that sits in unobtrusive cheap concrete boxes like the old Bell telephone exchange buildings.

The issue right now is every plant is a unique one-off. Meaning the inspectors need to pour over the plans, construction crews need to learn how to build each design specifically, fabricators providing parts need to make each plant's run of stuff special. If we could have just one standard nuclear plant design, even if it was silly curved roofs or whatever, it would massively decrease plant construction costs by taki…

To much energy is the central problem with nuclear. It’s capital intensive so if they don’t operate 24/7 their cost per watt increases. This puts Nuclear in a bind as wind and solar are both significantly cheaper and Nuclear is terrible as a peaking power plant.

In the end it needs to either beat Wind or Natural Gas. Meanwhile grid storage prices keep dropping which may soon start undercutting Natural Gas.

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#67

Post by acidburnNSA »

jcranmer wrote: post #61
petschge wrote: post #55

Earlier quoted context omitted.

While dam break cost lives, there is crucial differences that are never mentioned by the pro-nuclear crowd on HN. 1.) Dam breaks devastate much smaller areas. So even if the human toll is the same, the amount of infrastructure lost is smaller. 2.) The area is unlivable (or even inaccessible) for a much smaller duration of month instead of millenia. Maybe land lost "forever" (on the timescale of individual human lives…

Chernobyl's exclusion zone was ~1000 mi^2, consisting of ~120,000 people. The Oroville dam evacuation zone is ~250mi^2 encompassing ~180,000 people. Floods are no laughing matters; the Chinese decision to break the levees of the Yellow River during the Second Sino-Japanese War is credited with killing 400,000 people or so and rendering millions homeless, and the land was unusable for the better part of a decade, not…

Strengthening your point on the persistent anti-nuclear "uninhabitable for millennia" myth, check this recent article out [1]. The wildlife at Chernobyl is thriving. There are far worse energy accidents in other industries that cause far more and widespread damage.

[1] https://thoughtscapism.com/2019/05/08/worlds-worst-energy-ac...

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#68

Post by acidburnNSA »

beders wrote: post #63
acidburnNSA wrote: post #20

Earlier quoted context omitted.

100% safe is never the metric. Nothing is 100% safe. Every form of energy generation has risks that have to balance the good the energy source brings. Nuclear is nearly unique in that it can produce carbon-free energy (unlike fossil and biomass), continuously for 2 years on end between reloads (unlike wind/solar/coal), and it can be deployed in a wide variety of geographic locations (unlike hydro and geothermal). The…

A 1% failure rate is not acceptable. Nice try downplaying the actual consequences of a reactor incident like Chernobyl. Do I have to mention radioactive boars roaming in Bavarian forests again? The billions in costs to an economy? The only part I agree with you is that coal is a not an acceptable way to generate power. There's now sufficiently cheap power generators that don't devastate whole areas for centuries to c…

Core damage frequency of modern plants is in the 1e-6 to 1e-8 range/year. That's 4-6 orders of magnitude lower than 1%.

I highly recommend you read some recent info regarding Chernobyl [1]. I'm not downplaying it at all. I'm using quantitative numbers produced by teams of UN and WHO scientists.

RE cost: climate change will cost trillions. Nuclear power plants can prevent that cost.

"Centuries" is a persistent anti-nuclear myth. Again, see [1]. I don't think you're well justified in saying I'm downplaying Chernobyl when you're going on and saying stuff like this!

[1] https://thoughtscapism.com/2019/05/08/worlds-worst-energy-ac...

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#69

Post by goatgate »

Complexity is the enemy of any reliable system. No energy source is simpler than solar arrays. They don't require any moving parts, thermal management, waste containment, or strong security. The only maintenance required is dusting. Why otherwise intelligent people cannot appreciate the cost of complexity for nuclear energy is beyond me, especially when viewed in contrast to something as simple as solar.

Re: Making Nuclear Energy Smaller, Cheaper And Safer

#70

Post by fromthestart »

goatgate wrote: post #69

Complexity is the enemy of any reliable system. No energy source is simpler than solar arrays. They don't require any moving parts, thermal management, waste containment, or strong security. The only maintenance required is dusting. Why otherwise intelligent people cannot appreciate the cost of complexity for nuclear energy is beyond me, especially when viewed in contrast to something as simple as solar.

There are costs other than complexity which must be considered before selecting a power source. For example, energy density per unit area. Nuclear has a much smaller footprint. Also the cost, maintnence, lifetime, and environmental impact of batteries required during night time/occluded operation is also not trivial, as is accommodating for unpredictable outputs due to weather.
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