Why is Fukushima nuclear crisis so threatening?

petergreat

I don't understand. How can a nuclear plant accident produce more radioactive fallout than an atmospheric nuclear explosion? No nuclear test has ever triggered panic around the global fearing radioactive dust spread by wind.

Astronuc

When was the last atmospheric test of a nuclear weapon? What was the public reaction to that test?

How were more recent tests conducted? What was the public reaction?

How is current research of nuclear detonations conducted in the US?

Borek

I guess atmospheric tests were stopped before word "radiation" became synonym of "panic".

russ_watters

Heh - I'm annoyed I didn't think of that. For anti-nuclear activists, equating nuclear weapons and nuclear power has always been a key tactic. It's just that they haven't had anything to raise panic over in more than 20 years.

I would be curious to have a more concrete answer to the question though: how does an accident like this compare to an above-ground test? (which, it is my understanding, hasn't happend since the 1960s)

bcrowell

Interesting question!

A useful statistic in measuring how bad a radiation release is is how many curies of 131I were released. 131I is an efficient carcinogen.

Three Mile Island released 20 Ci of 131I.
Chernobyl released 7x10^6 Ci of 131I
Above-ground nuclear testing in Nevada released about 1.5x10^8 Ci of 131I.

It's likely that nuclear testing caused hundreds of thousands of excess thyroid cancers; Chernobyl thousands; TMI none.

Sources:
http://streaming-online-free.blogspo...ent-japan.html
http://books.google.com/books?id=tf0...curies&f=false
http://www.ips-dc.org/articles/nucle...hyroid_cancers

petergreat

A complication is that nuclear testing is sometimes done on high altitudes (e.g. >4000 m) to reduce fallout, while nuclear plants are all at ground level, though I don't know the exact numbers about how much difference this makes.

russ_watters

Excellent, that is exactly what I was looking for. Thanks very much.

Borek

Still, from what I remember, there is no Chernobyl effect visible in the epidemiological data - background is high enough to mask it.

CAC1001

I had read that one of the best ways to spread radiation over a country would be to detonate a nuclear weapon in the upper-atmosphere so that the wind blows the radiation around.

QuantumPion

A typical nuclear reactor fissions as many atoms as a nuclear bomb every 4 hours. A bomb is made up of a few kg of fuel, a reactor has as much as 100 tons. There are a lot more fission products in reactor fuel than a bomb explosion.

russ_watters

While I would tend to agree, it does depend on who you ask. Not that I'd ever ask them anything, but Greenpeace speaks loudly on the issue and some people listen.

minerva

Let's look at the Hiroshima bomb, for example. 15 kT of explosive yield, or so. That's equal to 17.43 GWh of thermal energy, if you convert the units.

Let's say a typical large nuclear power reactor has a thermal power output of about 3 GW.

That means it generates one bomb worth of energy - and one Hiroshima bomb worth of fission products - every 6 hours.

That's why the amount of fission products that can potentially be released from a severe reactor accident is, in theory at least, larger than from a bomb - because it has fissioned much more uranium, generated much more energy, and made much more fission products, than the bomb.

Joe Neubarth

It all depends upon the amount of further contamination of the planet. I do not know what normal background radiation was in 1940, but I am willing to bet that it is higher now than it was then.

Any amount of radiation can cause cancer to start growing in your body. Usually very low doses like a chest X-ray are dismissed as not causative; but, the reality is that your next X-ray could start a cancer growing in your body. We just do not know when the radiation can cause that type of damage. One thing we do know is that if we receive increasing doses, we increase the potential for Cancer to grow.

SO, people have a good reason to be afraid of any additional radioactive pollution to the planet. By being proactive, the life you save may be your Great Great Grandchild's.

rowmag

Atmospheric tests were generally conducted away from places where people lived.

NUCENG

LIFE EXPECTANCY

US WORLD
1950 69 46

2000 77 66

Obviously, background radiation, atmospheric testing, and nuclear power are major impacts on world health.

Dmytry

NUCENG:
Obviously gonna use the fact that nuclear testing did not manage to nuke away all the impact of advancements in medical science as some sort of point.

Easily. Chernobyl has released 890 times the Cs-137 (major medium term pollutant) of the nuclear bomb type dropped on Nagasaki. (albeit the bomb would of released also comparable amount of Sr-90 whereas reactor won't)
Over the time of operation, reactor produces far more energy than such bomb does. The short living isotopes in reactors decay during that time though, so if you compare the short living isotopes you get a smaller reactor:bomb ratio.

The atmospheric nuclear testing has released something on order of 740PBq of Cs-137 according to
http://www.davistownmuseum.org/cbm/Rad8.html
, Chernobyl has released 85 PBq or over one-tenth .

Remember that the typical nuclear power plant is not only a power plant, but also a MASSIVE radwaste repository. Much of the radwaste from the plant is stored on site. There can be 5 core loads stored right next to the reactor in a modern spent fuel pool (re-racked for storage). 4 reactors, and you get 24 cores. Much of the remaining radwaste is also somewhere on the site, in a common spent fuel pool.
The total inventory of Cs-137 at a nuclear plant of several reactors, including the spent fuel pools, can easily exceed by several times the total release from atmospheric nuclear testing. Simply walking away from a nuclear power plant (multiple reactors + radwaste repository) can result in a release exceeding that of all the atmospheric nuclear testing for the medium term pollutants (with half life of several decades).

Joe Neubarth

When you start tabulating the ever increasing number of people killed by radiation induced cancer it is obvious that the impact on health is MAJOR, and very sad, because it just does not HAVE to happen.