Japan Does Not Face Another Chernobyl

http://online.wsj.com/article/SB10001424052748704893604576198421680697248.html

by dicemoose • 15 years ago

113 70 15 years ago

online.wsj.com

dicemoose2• 15 years ago

Really appreciated the following especially as I try to balance local (JP) coverage and international news. "With all the death, devastation and disease now threatening tens of thousands in Japan, it is trivializing and almost obscene to spend so much time worrying about damage to a nuclear reactor."

ars2• 15 years ago

Is there any info about how many people were injured or killed from oil and gas fires?

Tichy• 15 years ago

I don't see how it is obscene. It makes sense to think about things you can do something about. I am sure in Japan they are also thinking about improving their defenses against Tsunamis right now. Where I live, Tsunamis really aren't a problem, but we do have nuclear power plants. We also have air that can be contaminated.

I actually feel sorry about the deaths and devastation in Japan, but I have no illusions that my feelings will do anything at all to help over there.

Btw., who knows how many people are currently dying in Libya. People are dying all over the place, all the time, unfortunately. I am just saying, maybe it would have been best if I hadn't even switched on the news, and concentrated on things that I CAN do something about.

marshray4• 15 years ago

"it is trivializing and almost obscene to spend so much time worrying about damage to a nuclear reactor."

* The nuclear situation is changing by the hour and people are making decisions and actively managing it.

* Having 3 to 5 nuclear reactors under various stages of meltdown is a big story in its own right. The existence of massive loss of life nearby does not diminish its importance.

* The earthquake+tsunami event is unlikely to get worse and there little people are able to do to prevent it anyway.

* Conflicting information keeps coming out about possible worst case scenarios (and their relative likelihoods) with the nuclear reactors.

* Some of these scenarios are, in fact, much worse than even the current unimaginably bad scenario. Just because things are bad doesn't mean they couldn't get worse.

* This has definite implications this for US and global energy policy. In my view, it's probably best to hold off that debate until these incidents are concluded and informs our hindsight, but the discussion is inevitable.

* The nuclear incidents are affecting rescue and cleanup. Rescue is hard enough without a 20km evacuation going on at the same time. For example there are reports that the US Navy had some ships which needed to relocate due to detected radiation.

* Tokyo, one of the largest cities in the world, faces a power shortage. Commuter trains are not running. It is unclear how long this will persist. This is a huge economic impact in its own right.

mpyne9• 15 years ago

> Conflicting information keeps coming out about possible worst case scenarios (and their relative likelihoods) with the nuclear reactors.

There is only one worst-case scenario, so although I very much agree that the information coming out of Tokyo Electric Power Co. and the Japanese national government is inconsistent, that doesn't mean new "worst-case" scenarios become possible.

IMHO the worst-case scenario is fuel melting through the reactor pressure vessel, through the thick steel containment which was not damaged in the hydrogen explosion, and through the bottom of the concrete containment (the top of which was damaged), and then from there into the environment.

The worst-case plausible scenario from what I can tell (which again, has been true from the moment they lost cooling systems for decay heat removal) is fuel melting to the bottom of the reactor vessel, possibly breaching the primary boundary but getting trapped by the steel containment, with possible further release of gaseous radioactivity.

I say this because cooling the fuel if it is outside the primary but inside the steel containment is much easier than cooling the fuel inside the primary: you must merely submerge the steel containment in seawater (which would boil away as it heats up), but this time you don't have to worry about pumping to high pressures. The fuel was transfer its heat across the steel containment to the seawater.

As long as the steel containment is intact (as was true last I heard, but refer to my earlier point about TEPCO) then there would be no additional release of radioactive contamination from this. If there are air leaks in the containment that would be worse, but a portable radiation monitoring device would quickly identify such areas so they can be quickly patched or covered to at least keep contamination from spreading.

So, I also disagree with "unimaginably bad". Unimaginably bad might be something like coal slurry breaking through its retention walls and killing all aquatic life in a nearby river for hundreds of miles (as actually happened in Kentucky in 2000 IIRC). At my last check all three reactors that had been operating at Fukushima-Daiichi have probably had fuel damage, which means that any steam they vent from the plant will contain radioactive contamination. So, definitely bad.

Unfortunately I can't seem to find to many numbers for activity concentration (how frequently the radionuclides are actually decaying) or for dose rate (a measure of biological damage per unit time). A Guardian article mentions 680 microsievert per hour to the northwest of the site, which would be 68 millirem/hour, which is a value that is actually fairly high, but far below levels that would lead to immediate health risk.

For a point of comparison, there are (inhabited ;) spots in the world (Ramsar, Iran) where you would receive 70 millirem/day, every day, which is far above what a trained radiation worker would be permitted to receive and yet still appears to have little (if any) effect on the local population.

Of course any unnecessary exposure is unacceptable! But I also wouldn't come close to calling it "unimaginably bad", except in regards to the economic cost to TEPCO and the substantial loss of generating capacity (which as you mention, can have a substantial economic impact).

neutronicus2• 15 years ago

That article makes it sound like the decision to use graphite is stupid and will never be made again. This isn't true, a lot of the gen-4 designs are graphite-moderated.

api• 15 years ago

But I am sure they take into account the properties of graphite, and I'm sure making sure that Chernobyl thing doesn't happen is high on the list.

neutronicus2• 15 years ago

Right, just pointing out that graphite is not in and on itself a stupid choice.

dublinclontarf• 15 years ago

Gen IV designs wont even be available to build before 2030. Your comment seems to imply that reactors with graphite are being built right now.

moblivu2• 15 years ago

With everything the Japanese are passing through at least they have some good news! I hope there will be a good ending to this !

zeigotaro• 15 years ago

Not sure I would describe the permanent loss of a critical power plant as "good news," but the aversion of a large radiation leakage is certainly less bad.

moblivu2• 15 years ago

Well with what their living knowing that a nuclear reactor won't blow up is still good news. I really hope it doesn't get worst...

btmorex2• 15 years ago

This is a bad article.

1.) He argues that the three mile island accident means that the containment vessel will hold now. Even if they were the exact same reactor design, that doesn't logically follow, but they aren't the same design which gives even less credence to this argument.

2.) He says that once the reactor is flooded with water they won't have to do any more pressure releases. Again, I don't see how that follows. As long as there is enough residual heat to boil water, there's certainly a possibility that they will have to do more pressure releases.

ars2• 15 years ago

1.) Reactors aren't magic. They have very well defined properties. It's pretty easy to calculate if a containment vessel will hold. This type of engineering happens every day in every building you go in and every car you ride.

2.) The containment structure is quite large, and the residual heat is relatively low. There is a lot of water there, presumably too much for the residual heat to boil. (The water normally flows only in the much smaller reactor vessel.)

btmorex2• 15 years ago

I'm not trying to convince anyone that the containment vessel will fail or that they will have to do more steam releases. I'm simply saying that the arguments presented in the article are illogical.

adsr6• 15 years ago

Three reactors are affected, and two plants, Fukushima and Onagawa. I would say that an earth quake and tsunami is outside the well defined.

_delirium4• 15 years ago

On #1, it's specifically the TMI comparison in the article that isn't very convincing, because many of the postmortems (though there is some disagreement) conclude that it was somewhat luck that the corium didn't melt through the containment at TMI, due to the specific pattern of melting and cooling. So the fact that it held doesn't tell you what would happen in another incident with much confidence (even if the two designs were the same, which they aren't). There may be other reasons to conclude that breaching containment is unlikely, but the particular argument the article presents isn't a great one.

mbateman• 15 years ago

> He says that once the reactor is flooded with water they won't have to do any more pressure releases. Again, I don't see how that follows.

He's just not stating the (true) premise that the seawater will be able to absorb the heat; he's implying it and relying on it. That doesn't make the article illogical, it makes it mildly enthymematic.

tea32• 15 years ago

If there is no risk of the second containment level being breached why do newer reactors have a third level containment (which is missing from these older reactors)? I'm just curious.

_delirium4• 15 years ago

One reason is "the last level of containment held" doesn't give engineers the safety margin they want, or the public-reassuring PR they'd want. Much better to be able to say that the last level of containment is never even relied on, but is purely insurance.

tea32• 15 years ago

Thank you. If the fission reaction has indeed stopped, I wonder if whatever heat is still being generated (especially if the fuel rods are exposed and enough heat exists to melt the cladding) would still pose some danger to the pressure vessel?

fxj4• 15 years ago

do the math: http://edition.cnn.com/2011/WORLD/asiapcf/03/14/japan.us.nav... says the USS Ronald Reagan has been 100 miles away when "airborne radioactivity" was detected, and http://www.dailymail.co.uk/news/article-1366055/Japan-earthq... says that U.S. Navy crew in relief effort get a month's radiation in just one hour. From wikipedia: The worldwide average background dose for a human being is about 2.4 millisievert (mSv) per year, which is 0.2 mSv per month. i.e. 100 miles away they measured 0.2 mSv/h which, if we assume a r-squared dependency, 2 Sv/h within one mile at the reactor. Let's be conservative and assume linear dependence, then we still have 0.02 Sv/h which is a rather significant dose per hour. A dose greater than 0.5 sievert (Sv) is considered to be a high dose of radiation. With absorbed doses of 1 to 2 Sv and above, mortality is expected to be about 20%, according to radiation medicine specialists. Above a dose of 7 Sv the survival rate is zero.

bhousel• 15 years ago

The pilots picked up the radiation while flying around the plant as it was venting steam. They didn't pick up that radiation at the aircraft carrier 100 miles away, so your assumptions about crazy high levels of radiation at the facility don't add up at all.

fxj4• 15 years ago

the ship personnel got the dose!

http://abcnews.go.com/International/uss-carrier-ronald-reaga...

"The maximum potential radiation dose received by any ship's force personnel aboard the ship when it passed through the area was less than the radiation exposure received from about one month of exposure to natural background radiation from sources such as rocks, soil, and the sun," Davis said.

According to 7th Fleet Commander and Spokesman Jeff Davis, the ships were moved away from the downwind direction of the plant as a precautionary measure on Sunday.

pwim• 15 years ago

Tests detected low levels of radioactivity on 17 U.S. Navy helicopter crew members when they returned to the USS Ronald Reagan

These were members of a rescue crew, who were most likely far closer to the incident than the ship itself.

fxj4• 15 years ago

http://www.dailymail.co.uk/news/article-1366055/Japan-earthq...:

"The helicopters sounded the alert around 60 miles from the coast and the ship’s sensors also sounded when it was 100 miles north east of the plant."

fxj4• 15 years ago

here are some real data (sorry, in german):

http://www.grs.de/informationen-zur-lage-den-japanischen-ker...

there was a peak at 1.2 mSv/h when the meltdown occured. All in all the values are in the range of 0.4-1 mSv/h. At least a factor 10 lower as I found in the approximation above.

sedachv• 15 years ago

What does that come out to in units of banana? http://en.wikipedia.org/wiki/Banana_equivalent_dose

mpyne9• 15 years ago

> i.e. 100 miles away they measured 0.2 mSv/h which, if we assume a r-squared dependency.

You can't assume an r-squared dependency, as the radiation they were measuring came from the radioactive steam that had drifted out to sea (i.e. the "airborne radioactivity"). It was not from the Fukushima-Daiichi site directly (after all, there's many different radiation monitoring stations nearby that have much better indications of general area radiation levels).

In fact you proved yourself wrong! If being a mile away from the reactor gave you 2 Sv/hour, and no one lives past 7 Sv, that's only 3.5 hours anyone could survive, and there have been workers at the site for days now.

vilhelm_s2• 15 years ago

I certainly agree with his main point: the nuclear reactor accidents are a comparatively small part of the earthquake catastrophe. But the rest of the article reads like pure propaganda-- like he started out writing the article with the goal of downplaying rather than assessing the risks involved.

I can spot at least one inaccuracy. He claims that TMI showed that there is no risk of nuclear fuel melting through the steel containment structure. But at TMI, the core was actively cooled through the entire incident, and the temperatures were not even high enough to melt the fuel itself. So this does not given any information about what would happen in the absence of cooling.

_delirium4• 15 years ago

I agree his TMI comparison isn't very useful, but about 1/3 of the fuel at TMI did melt, according to http://www.ans.org/pi/resources/sptopics/tmi/whathappened.ht...

webXL• 15 years ago

I wouldn't call it propaganda if your merely trying to get people to put facts of an entire tragedy into the proper context. Yesterday morning I turned on the ABC and saw this: http://yfrog.com/h7r6rmcj CNN has been treating the nuclear accidents with equal importance, just because they know it freaks people out, publishing numerous errors on their website, according to one MIT scientist (Dr Josef Oehmen): https://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-w...

Don't get me wrong, there is definitely propaganda on both sides, but the anti-nuclear crowd pouncing on this before we have all the facts, and while there's a race against the clock to find survivors and prevent more loss of life, is counter-productive.

hcurtiss• 15 years ago

Thank you for the Oehmen link. Supremely useful.

mpyne9• 15 years ago

> He claims that TMI showed that there is no risk of nuclear fuel melting through the steel containment structure. But at TMI, the core was actively cooled through the entire incident, and the temperatures were not even high enough to melt the fuel itself.

Actually, about 1/3 to 1/2 of the Three Mile Island core melted completely (i.e. far worse than mere zirconium cladding damage).

This was because the Three Mile Island core was not continuously cooled. There were a couple of elements to this:

1. In normal operation, the primary system is kept highly pressurized to ensure that the primary coolant does not boil. The way this is done, however, is to use something called a pressurizer, which does have a steam bubble, for much the same reason cars use shock absorbers. When the steam flow was cut off to the turbine generators, that acted as a loss of the heat sink that had been cooling the reactor, which caused pressure to go up.

When pressure got too high, a relief valve in the pressurizer automatically lifted to relieve the pressure increase and maintain primary piping integrity. The valve was supposed to automatically shut once the pressure dropped enough, but did not. The indication that the operators had showed that the valve had been commanded to shut, but did not show that the valve had not actually shut. The location of the leak tended to artificially increase water level in the pressurizer by essentially "sucking" it from the reactor vessel (the operators had no indication of reactor vessel water level, since it was normally completely full of liquid).

This loss of water from the reactor meant that it uncovered the fuel much quicker than might otherwise be expected. The operators had other ways of telling something was wrong (such as the sharp pressure drop from a stuck open relief valve) but did not put the puzzle together. They even did worse: Automatic safety systems kicked on to force-fill the reactor with cooling water, but the operators were afraid the system would overflow the entire primary (remember, they thought there was still water in the reactor vessel), so they dampened the flow, then shut off the system completely.

2. As steam started forming in the reactor vessel, the coolant loop piping connecting the reactor vessel to the reactor cooling pumps started to fill with steam, which caused the reactor cooling pumps to cavitate (which is certainly not good for the pumps). The operators had indication of this, but assumed the cavitation was due to the pressure drop and, again thinking the core was still covered with water, they shut down the reactor cooling pumps. This represented the loss of the last line of defense against reactor meltdown.

It was not until some hours later when a different shift relieved that it was realized that a relief valve was stuck open and that there was no water over the fuel. They started re-established cooling at this point, but the damage was already done.

vilhelm_s2• 15 years ago

Ok, I misremembered and my comment was wrong. For about 40 minutes all the cooling pumps were turned off, and during the following 7 hours cooling was ineffective due to hydrogen bubbles. (http://www.threemileisland.org/downloads//195.pdf). The core partially melted. Sorry.

This doesn't make the original article any more correct though. During most of the TMI accident the core was being actively cooled, and in fact it never got uncovered enough to even completely melt. So this still does not tell us anything about how containment would work in the absence of cooling.

orblivion• 15 years ago

"These produce radiation at about the level of one dental X-ray in the immediate vicinity and quickly dissipate."

How do you compare nuclear radiation/poisoning (apples) to electro-magnetic radiation (oranges)?

gallamine2• 15 years ago

It's all electro magnetic. It's an issue of energy. See: http://en.wikipedia.org/wiki/Ionizing_radiation

kahirsch• 15 years ago

No, it's not all electromagnetic. Alpha, beta, and neutron radiation are not electromagnetic radiation.

There's also a very big difference between radiation and radioactive isotopes, which can be inhaled or ingested.

face• 15 years ago

I think it's relevant to point out that this is not a news article written by a reporter; it is an opinion piece written by someone who has a very specific viewpoint.

This is not ad hominem, I am not claiming anything about the correctness of his claims. However, I think it is important to distinguish this from the other numerous WSJ pieces on the situation of nuclear plants in Japan right now.

VladRussian2• 15 years ago

>it is an opinion piece written by someone who has a very specific viewpoint.

whether a core melts through the containment vessel or not depends on specific temperature that pool of melted uranium on the floor will develop. That in itself depends on the geometrical shape of the pool, uranium enrichment degree and presence of the neutron moderator material in the pool. That in itself depends on a bunch of other things ...

Nowhere it depends on the opinion or a viewpoint.

VladRussian2• 15 years ago

in Chernobyl it was burning graphite, in this case we have water being separated into hydrogen and oxygen and later explosively recombining back - the 2 reactors have exploded so far.

The differences:

- burning graphite was adding energy, in the current water case - the energy is provided only by the core.

- containment structure.

So, while there is obvious similarity to Chernobyl, there is very significant quantitative difference as to the intensity of the process. As long as the core temperature going down, it should be fine. Is it going down?

bluedanieru2• 15 years ago

I keep hearing that this is the second-worst nuclear disaster after Chernobyl. Folks, this isn't even the second-worst nuclear disaster on Japanese soil.

bluedanieru2• 15 years ago

Gee, thanks for the downvote. Why don't you come on over to Tokyo and we can have a chat about it.

Japan Does Not Face Another Chernobyl

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