Earlier quoted context omitted.
What happens if the swimming pool leaks ?
What happens if a windmill explodes?
Making Nuclear Energy Smaller, Cheaper And Safer
81–90 of 116 posts
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#82Earlier quoted context omitted.
What happens if the swimming pool leaks ?
I mean ... millions of people who barely maintain their homes avoid pool leaks, and when it does leak, it tends to be slow enough that they can call in a professional to fix the problem. Imagine a fastidiously maintained facility ... I think they can probably work it out
Yes, but the expected value of harm from my backyard pool leaking is, well, I can't swim and I need to resurface the pool liner. Multiply this issue by the probablity that it'll happen at all, and you get, well, a filled pool to swim in.
But the expected harm from a SNR like this having a leak is decidely not the same. Yes, the leaks may be rare, but the outcomes from such a leak occuring have Chernobyl-like outcomes in their failure trees. The probability calculus still may return that this design is quite fine, given the risk tables, but you MUST run the numbers. Hand waving is not ok here.
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#83Although I'm not a big nuclear power fan for various reasons, I'm really happy to see someone approaching it with an eye to realistic safety, modern economics, and compatibility with a renewable-based grid. It'll be interesting to see if this can compete financially with batteries.
May I ask why you aren't a fan?
Another reason, as I have a moment to write... vulnerability to terrorist/military action. It's not enough to safeguard a plant against accidents. It needs to be safeguarded from malice as well - including inside jobs (a knowledgeable operator manipulating the controls, with full authorization) and brute violence, which could be crashing a fully fueled airliner into it or attacking with a bunker-busting military drone. What happens if your nuclear plant is hit with a weapon designed to destroy a modern military bunker complex? (Which could be a state actor, or an act of terrorism that somehow takes over a drone.)
Now, what happens when you blow up a windmill?
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#84Earlier quoted context omitted.
You have to consider stuff like terrorist attack and so on. Nobody is so incentivized in making your backyard pool leak.
The pool, as far as I can tell, is built pretty sturdy. Breaking this amount of concrete takes a lot of high explosives, and breaking it underwater is an order of magnitude harder. The Allies at WWII had to go to a great length to damage German dams, while using multiple heavy bombers. If terrorists were in possession of such amounts of powerful explosives, and a capacity to place them inside a highly guarded area, t…
It's not human action that would worry me, it's nature. Freezing cycles could easily erode a pool in a few decades and make micro-cracks that fester unnoticed for years. Rust is an ever present issue for re-inforced concrete and is the cause of countless civil engineering disasters.
Practical Engineering on Youtube is a great overview of the issues we humans have with water: https://www.youtube.com/user/gradyhillhouse/playlists
Of interest here are these videos:
https://www.youtube.com/watch?v=eImtYyuQCZ8&list=PLTZM4MrZKf...
https://www.youtube.com/watch?v=0EzoHXEzdwY&list=PLTZM4MrZKf...
https://www.youtube.com/watch?v=EACkiMRT0pc&list=PLTZM4MrZKf...
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#85Earlier quoted context omitted.
While you are correct that it is less than the nominal heat output, we are still talking about 50MW a minute after shut down and 5MW one day after the shutdown of a 700MW reactor. So even a day after the shutdown you are able to boil of 2kg of water every second.
Yes, it is still a lot of heat. But to a lay reader, it might be easy to believe that the pool needing to be able to cool the reactor means that the pool has to cool an operating plant during an accident which is incorrect. I was just trying to make the distinction here. Also the drop from (your very approx numbers) 50 MW to 5 MW is mostly exponential - and so very quickly drops away from 50 MW. After that, any remai…
Funny little detail that might interest you: Due to the presence of a large number of different fission products (with different half lifes), the drop does not really follow an exponential but is better described by P(t) = P_0 * a * (t^-0.2), i.e. a power law, where P_0 is the power before the shutdown, a is a couple of percent and t is the time since the shutdown in seconds.
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#86"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…
"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."
Out of curiosity, how is heated water circulated through the pool? I have this sudden vision of the reactor boiling the water around it and being surrounded by a pocket of steam. Or, the repeated formation and collapse of a steam bubble, which can't be good.
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#87" "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. " If it's safe, it should easily meet the criteria and so shouldn't need exemptions and exceptions, right?
The idea is to save on some costs of monitoring equipment and recertification per each module.
Good luck...
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#88Earlier quoted context omitted.
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.
No, it is meant to beat base load plants, that is oil, coal, natural gas, biomass, geothermal and hydroelectric.
Wind is somewhat bad as base load plant as there are serious lulls when wind is relatively globally low.
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#89Earlier quoted context omitted.
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.
Don't forget maintenance stations and other office housing required to run the plant.
Re: Making Nuclear Energy Smaller, Cheaper And Safer
#90Earlier quoted context omitted.
> Union of Concerned Scientists are an anti-nuclear lobbyist group. Or maybe they are just concerned about a power source which has proved catastrophic multiple times in the past.
Compare the number of deaths due to nuclear accidents to the health effects of us all breathing in coal pollution.
Deaths / trillion kWhr (https://www.forbes.com/sites/jamesconca/2012/06/10/energys-d...)
Coal – global average 100,000 (41% global electricity)
Coal – China 170,000 (75% China’s electricity)
Coal – U.S. 10,000 (32% U.S. electricity)
Oil 36,000 (33% of energy, 8% of electricity)
Natural Gas 4,000 (22% global electricity)
Biofuel/Biomass 24,000 (21% global energy)
Solar (rooftop) 440 (Wind 150 (2% global electricity)
Hydro – global average 1,400 (16% global electricity)
Hydro – U.S. 5 (6% U.S. electricity)
Nuclear – global average 90 (11% global electricity w/Chern&Fukush)
Nuclear – U.S. 0.1 (19% U.S. electricity)
I've never been quite enthusiastic about these kinds of numbers, because I'm not sure what deaths are included. I believe this article includes indirect, pollution-related deaths for fossil fuels, but what about deaths in uranium mining and processing?
Forbes separates out the US numbers because of the strong regulatory regime here---which strikes me as odd; doesn't Forbes usually consider environmental and health-and-safety regulations bad?
One confounding factor in this data is the low numbers of large-scale accidents for nuclear power. The reason the hydro power number is so high is a number of very large dam failures; would nuclear numbers be similar if Chernobyl happened in a much higher population area or if Fukushima happened faster?