Fukushima-How bad is it?

[Silurian]

And some cements (if I'm not mistaken) are made with coal ash as a filler/binder. In addition to being toxic, that stuff is also fairly radioactive. People who complain about radiation from nuclear power plants don't often realize how much more radioactive coal power plants are - and the poorer the country you live in, the more radiation the plants are likely to spew thanks to lower grade coals being used and far fewer environmental controls on the plants.

PFA (pulverised fuel ash) is added to cement to increase the durability of the concrete. It reacts with water in a similar manner too cement but gains strength over a longer time. It is an exothermic reaction so if the reaction takes place over a longer period of time the peak temperature of the centre of the concrete will be lower.The thermal stress caused by a high temperature range would cause cracking which would let water into it in the future. High temperatures may also cause unwanted chemical reactions in cement. It does have the disadvantage of reducing early strenght.

The PFA would be added to the cement after the cement had been "burnt" normally before shipment

Ground-granulated blast-furnace slag is also blended with cement.
.
There is a jetty across the bay, from civ, which may be something to do with the cement works, I have not looked back at Civs photos. So they could ship in PFA blend it with the cement before shipment out. Obviously this could produce dust which could blow across the bay.


PFA is lighter than chalk, sands and gravel or clay; so it is used in construction as a lightweight fill for embankmenst. An embankment made of PFA would be about 25% lighter which would reduce the settlement.

If there is not good dust control during construction PFA dust will be blown off the embankment.

 

[Sommerswerd]

What is the air speed velocity of an unladen swallow?

I am shocked and frankly appalled that no one answered this correctly.

The answer is obviously "What do you mean? African or European swallow?"

 

[hobbsyoyo]

Yeah, coal ash contains lots of naturally occurring thorium and uranium, along with other fun heavy metals like arsenic and cadmium. When coal gets burned, everything that isn't combustible, including the heavy metals, remains in the ash ash and can escape as fly ash. Whatever doesn't escape remans and has to be dumped into ash ponds or just regular landfills, or reused by incorporating it into concrete.

Under normal conditions, coal power plants release more radioactive stuff into the environment than do nuclear plants, by quite a bit. It's just that this is routine and nobody thinks about it, whereas nuclear disasters are extremely rare but spectacular and release enormous amounts of radioactive materials, mostly fission products like I-131, Cs-137, and Sr-90. Those can be really nasty around the affected area, but nobody needs to worry unless an accident happens within a couple hundred km of you.

But the fact that radiation is easy to detect at levels far smaller than anything dangerous, and that Geiger counters make loud and frequent clicks, mean that it's easy to create a panic around nuclear power while very few people care about the everyday environmental damage of coal.

There's also an enormous amount of misinformation and lack of education on the topic. I feel the anti-nuclear movement has an awful lot in common with the anti-vax movement in that respect.

 

[FriendlyFire]

There's also an enormous amount of misinformation and lack of education on the topic. I feel the anti-nuclear movement has an awful lot in common with the anti-vax movement in that respect.

Yeah just read that California had an Child Asthma epidemic until they banned all the coal fire power plants
Nuclear power on the other hand engenders fears, probably thanks to the Cold war and the spectacular Chernobyl meltdown

 

[CavLancer]

I am shocked and frankly appalled that no one answered this correctly.

The answer is obviously "What do you mean? African or European swallow?"

The youth of today

 

[Silurian]

There's also an enormous amount of misinformation and lack of education on the topic. I feel the anti-nuclear movement has an awful lot in common with the anti-vax movement in that respect.

I would agree that there is an "enormous amount of misinformation and lack of education on the topic" but where did this start.

The first "commercial" nuclear power station in the UK, Calder Hall, at what is now called Sellafield was opened by the Queen in 1956 as an electricty production facility. Its true purpose was to produce plutonium for UK weapons. At this time the risk from radioactivity was under rated, by the industry, which is demonstrated by the "storage" of waste at Sellafield and other places. So the anti nuclear power movement started as an anti nuclear weapons movement. Sellafield currently has about 112 tonnes of plutonium, some from overseas, which is supposed to be reprocessed.

Now the industry has a more realistic view of the risks but the public now knows about past mistakes.

People view different risks in different ways. Risks that people can control are viewed as being "lower" than ones that they can not. Look at the way people view car, bus, train and plane crashes.


I worked for two years in a live nuclear power station and feel that nuclear power stations are safer than other large industrial process.

There is a reluctance to include the decommissioning costs into nuclear power generatation because it would most likely show that it is uneconomic.
Many people will view that if the nuclear industry is not presenting all the costs what else are they not presenting about risks.

 

[Thorgalaeg]

I once was pro-nuclear until i learnt how much heavily subsidized and how uneconomic it is. Of course you will heard a lot more about subsidies going to renovables than the ones going to the energy giants owning nuclear plants.

 

[hobbsyoyo]

Historically, petroleum products and coal have been heavily subsidized as well. And I don't care so much if the economics of nuclear don't pan out if
A. The country can afford the subsidy
B. It keeps megatons of carbon dioxide and other pollutants out of the air


Fighting climate change is going to be expensive and we shouldn't act like it won't be.

 

[Timsup2nothin]

Historically, petroleum products and coal have been heavily subsidized as well. And I don't care so much if the economics of nuclear don't pan out if
A. The country can afford the subsidy
B. It keeps megatons of carbon dioxide and other pollutants out of the air


Fighting climate change is going to be expensive and we shouldn't act like it won't be.

Very rational arguments that would be totally outmatched by one person who couldn't correctly define the word chanting "radiation, radiation, radiation" at the top of their lungs.

 

[Silurian]

Historically, petroleum products and coal have been heavily subsidized as well. And I don't care so much if the economics of nuclear don't pan out if
A. The country can afford the subsidy
B. It keeps megatons of carbon dioxide and other pollutants out of the air


Fighting climate change is going to be expensive and we shouldn't act like it won't be.

As an engineer I like big sexy projects but we still do not know the whole life cost of nuclear.

Nuclear is not the answer to climate change, we need a set of solutions that will work everywhere.

 

[Cutlass]

Historically, petroleum products and coal have been heavily subsidized as well. And I don't care so much if the economics of nuclear don't pan out if
A. The country can afford the subsidy
B. It keeps megatons of carbon dioxide and other pollutants out of the air


Fighting climate change is going to be expensive and we shouldn't act like it won't be.

The problem with this is that we can get all those benefits, without the risk, with lower costs, and without the end game costs of nuclear, with renewables. So there's no case to be made for nuclear.

 

[Timsup2nothin]

The problem with this is that we can get all those benefits, without the risk, with lower costs, and without the end game costs of nuclear, with renewables. So there's no case to be made for nuclear.

Mostly agreed, although that wasn't true thirty years ago, and nuclear would have been a good option then

 

[hobbsyoyo]

What Tim said. It's really only recently that manufacturing and installation costs for renewables have dropped low enough for them to make any rational sense. Furthermore Cutlass assumes that the end state of nuclear energy (radioactive waste) cannot be fixed. I'm not sure about that but I'm much less bullish on it than the future of renewables which is becoming the clear best option in many scenarios.

 

[Hygro]

The radioisotopes that Fukushima has discharged make for interesting tracers to study fish migration and the transport of nutrients across the ocean as fish eat each other. Some marine biologists used cesium-134 and cesium-137 to do this, and were able to find detectable levels in fish off the West Coast within a year or so.

So I went to the fish market and bought some to add to my collection of radioactive stuff I keep in my apartment.

Am I understanding correctly?

 

[Bootstoots]

Hey now, I didn't say that. I have a very nice collection of radioactive stuff, and I'm not going to spoil it by adding in some fish whose radiocesium levels are far lower than the potassium-40 present in it and every other living thing. Plus it would start rotting and stinking up the place.

I'm good on radiocesium, actually. I have a 1 uCi sealed source of Cs-137 and a piece of trinitite, the radioactive glass from the Trinity nuclear test, which also has Cs-137. I've blown more money than I care to admit at this site.

 

[CavLancer]

Hey now, I didn't say that. I have a very nice collection of radioactive stuff, and I'm not going to spoil it by adding in some fish whose radiocesium levels are far lower than the potassium-40 present in it and every other living thing. Plus it would start rotting and stinking up the place.

I'm good on radiocesium, actually. I have a 1 uCi sealed source of Cs-137 and a piece of trinitite, the radioactive glass from the Trinity nuclear test, which also has Cs-137. I've blown more money than I care to admit at this site.

Heard a story years ago Boots about the Soviets deploying buoys, lighted with horns, that were powered by a small nuclear plant of some sort that would produce power for a few hundred years. Obviously that would be a handy thing to have off grid. The buoys all mysteriously disappeared...

 

[Timsup2nothin]

Heard a story years ago Boots about the Soviets deploying buoys, lighted with horns, that were powered by a small nuclear plant of some sort that would produce power for a few hundred years. Obviously that would be a handy thing to have off grid. The buoys all mysteriously disappeared...

Probably a hot source thermocouple using the ocean as a heat sink. That would be really effective, but as you say an attractive theft target. Best just keep using those to power satellites.

 

[red_elk]

If it's "small nuclear plant", he most likely talks about Riteg. A power generator which converts heat from radioactive decay to electric power. Used in remote research stations, space probes, etc.

 

[Timsup2nothin]

If it's "small nuclear plant", he most likely talks about Riteg. A power generator which converts heat from radioactive decay to electric power. Used in remote research stations, space probes, etc.

That's a hot source thermocouple. You weld two alloys together, attach one to a heat source (like a decaying radioactive source) and the other to a heat sink (like a cooling fin in the ocean or sticking out in space) and if you use the right alloys electrons are 'pushed' by the heat transferring across the boundary. Provide a circuit for the electrons to get back where they came from and they power the circuit. Has no moving parts and will last for as long as the heat source and heat sink last, which can be a very long time.

 

[Bootstoots]

Yeah, that thermocouple mechanism is how radioisotope thermoelectric generators work. In the Soviet case, it was strontium-90 (half-life 28.8 years), which I mentioned earlier. It's one of the most common radioactive fission products - everyone with nuclear plants has a lot of unwanted Sr-90 around, and it's a pure beta emitter (no gammas) so it's pretty easy to shield against. We use the same concept with plutonium-238 (pure alpha, 87.7 y) for deep space probes including both Voyagers, both Pioneers, New Horizons, the Curiosity rover, and Cassini.

edit: It's worth saying that the Soviets also had real nuclear reactors aboard satellites. One of them crashed in northern Canada in 1978, and the Canadians had to bill the Soviets for cleanup costs.