The "more political thread" besides "Japan Earthquake: nuclear plants" scientific one


by jlduh
Tags: scientific
Luca Bevil
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#505
Sep26-11, 11:26 AM
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Quote Quote by alpi View Post
I don't think it is meaningless to have the fuel elements and/or corium covered with water that is no longer boiling, either by heat exchange or by continuous replacement with purified cold water.
Covered ? quite dificult to ascertain since the exact location of the corium is not known.
One can only say that temperature at the positions where termocouples are is less than 100 degrees Celsius. which is of course better than registering a higher temperature, especially if there is a decreasing trend, but is far from a normal cold shutdown condition.
tsutsuji
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#506
Sep28-11, 02:05 PM
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Quote Quote by zapperzero View Post
How common is this in Japan? The new cabinet is just a week old, no?
Ryu Matsumoto resigned after one week in July:

Japan's Minister for Reconstruction Ryu Matsumoto has announced his resignation after just a week in the job.

He had been widely criticised for making insensitive remarks to governors of areas badly affected by March's deadly earthquake and tsunami.
http://www.bbc.co.uk/news/world-asia-pacific-14024206
Minoru Yanagida resigned over a gaffe in November 2010. He had been minister of Justice for less than 3 months:

Japan's justice minister resigns after gaffe
http://www.guardian.co.uk/world/2010...inoru-yanagida
sp2
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#507
Sep28-11, 05:30 PM
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Quote Quote by Borek View Post
You don't need boiling to see steam. Common misconception.

Borek--

Please don't tell me you would look me in the eye and state that you honestly believe there's nothing boiling in there.

Please.
Borek
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#508
Sep29-11, 01:48 AM
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I have no idea what is going on inside. But concluding something is boiling just because you see a steam is wrong.
NUCENG
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#509
Sep29-11, 02:43 AM
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Quote Quote by Caniche View Post
Propaganda, popular ,spin ; cold infers inactivity ,benign ,harmless ;shutdown implies absolute control,mastery ,total authority.
Hard to see how you can claim either or both when you don't know if your sensors are working or where your fuel/debris mix is located?
I am the engineer that pointed out that cold shutdown is a technical term with a legal definition that is not applicable to the Fukushima reactors.

Now I will also state that the term propoganda is equally suspect. As I said before, communication and translation from Japanese to English is one source of inaccuracy. Another is in the media interpretation of what they have been told. These can be innocent errors. However, your use of the word propoganda is deliberate and implies intentional miscommunication. Your previous posts clearly demonstrate your bias. So unless you are prepared to prove your assertions, I will simply categorize your posts as propoganda too.

Edit:

TEPCO does not yet consider the plants in cold shutdown. see:
http://www.reuters.com/article/2011/...7KS28V20110928
zapperzero
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#510
Sep29-11, 04:54 AM
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Gentlemen and ladies of PF.

I would like to point out to all of you that this thread is right at the very edge of what is acceptable on physicsforums anyway. It's quite normal, therefore, that moderators lack experience and regulars become uncomfortable with the deluge of spin, propaganda, counterprop and plain all-out kookery.

But that's what this thread is for! Think of it as a bag where all the unruly kittens can be stuffed. Tolerate the odd outburst of noise and the occasional squirming...
Astronuc
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Sep29-11, 08:27 AM
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Quote Quote by Caniche View Post
Propaganda, popular ,spin ; cold infers inactivity ,benign ,harmless ;shutdown implies absolute control,mastery ,total authority.
Hard to see how you can claim either or both when you don't know if your sensors are working or where your fuel/debris mix is located?
Quote Quote by sp2 View Post
Quick question: If it's "no longer boiling," where's all that steam coming from?


(And yes, of course it's propaganda to call it 'Cold Shutdown.'

'Cold Shutdown' applies to Nuclear Reactors. Like, *intact* Nuclear Reactors.
We don't have anything remotely resembling that here.

Calling it 'Cold Shutdown' is like opening the drawer of the hospital morgue to pull out a patient who's been dead for a week, taking his temperature, and saying, "Well, he's definitely *stable*."
Don't read more into the terminology than temperature at 1 atm.

NUCENG has already discussed the use of the term.

Cold shutdown
The term used to define a reactor coolant system at atmospheric pressure and at a temperature below 200 degrees Fahrenheit following a reactor cooldown.
http://www.nrc.gov/reading-rm/basic-...-shutdown.html

Shutdown implies that reactor/core is subcritical.
zapperzero
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#512
Sep30-11, 05:32 AM
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http://online.wsj.com/article/SB1000...581004368.html
Japan Officials Failed to Hand Out Radiation Pills in Quake's Aftermath says the title.
So much fail.
tsutsuji
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#513
Sep30-11, 01:42 PM
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http://online.wsj.com/article/SB1000...288145094.html "Japan Panel Says Nuclear Agency Manipulated Forums"

http://mdn.mainichi.jp/mdnnews/natio...na007000c.html criticality accident anniversary: Tokai Mayor "showed his anti-nuclear position."
tsutsuji
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#514
Oct4-11, 06:04 AM
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http://mdn.mainichi.jp/mdnnews/news/...dm010000c.html "The head of Japan's largest labor organization said Tuesday that the 6.8 million-strong body will seek to eventually realize a society not dependent on nuclear power, marking a shift from its previous stance of promoting atomic energy."
joewein
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#515
Oct4-11, 09:30 AM
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Quote Quote by tsutsuji View Post
http://mdn.mainichi.jp/mdnnews/news/...dm010000c.html "The head of Japan's largest labor organization said Tuesday that the 6.8 million-strong body will seek to eventually realize a society not dependent on nuclear power, marking a shift from its previous stance of promoting atomic energy."
...which reminded me of a quote in a Japan Times interview with freelance journalist Satoshi Kamata published on Oct 2:

What was your motivation in helping to organize the anti-nuclear demonstration in Tokyo on Sept. 19?

I planned the demonstration because right after the Fukushima crisis no citizens' groups seemed able to organize anti-nuclear rallies. In France or Germany, citizens' groups organized demonstrations numbering 200,000 or 300,000 people. In Japan it is difficult to hold such massive rallies.

Why is it difficult in Japan?

In Japan, labor unions have been the main organizers of massive demonstrations, but Rengo (the Japanese Trades Union Confederation) is not against nuclear power because it represents workers in the nuclear industry.

However, since May there have been many ordinary citizens, mainly young people, organizing anti-nuclear rallies that have typically attracted about 10,000 demonstrators.

So I thought that I should help to organize an even bigger demonstration, and I added my efforts to those of eight other co-organizers.
So if Rengo switches sides, it could be quite an interesting development, also considering the close links between Rengo and the currently ruling Democratic Party.
tsutsuji
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Oct14-11, 02:53 PM
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http://mainichi.jp/select/jiken/news...40029000c.html The ministry of education is publishing and distributing to schools new versions of reading books about radioactivity. Expressions such as "Nuclear plants are built in such a way that makes them safe from big earthquakes or tsunamis" that were written in the old versions have been removed.
clancy688
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#517
Oct14-11, 10:08 PM
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Quote Quote by tsutsuji View Post
Expressions such as "Nuclear plants are built in such a way that makes them safe from big earthquakes or tsunamis" that were written in the old versions have been removed.
That says a lot about their "newfound confidence" in safety measures. It probably would have been enough if they'd just slipped a "are supposed to be built in such a way" into the text, but I won't complain.
tsutsuji
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#518
Oct16-11, 08:27 AM
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http://www.yomiuri.co.jp/dy/national/T111015002391.htm English article about nuclear science education in Japanese schools.
Astronuc
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Oct16-11, 09:27 AM
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Also from Yomiuri, NISA secretly calculated Fukushima meltdown risks / Agency considered worst-case scenario of 'China syndrome'
http://www.yomiuri.co.jp/dy/national/T111015002539.htm

The agency [NISA] was working on the calculations just as TEPCO was saying the nuclear fuel in three reactors at the plant was "slightly damaged."
The key statement is: "The calculations indicated that if cooling water could not be injected, . . . ."

So why didn't TEPCO come out and say that they believed some fuel may have melted. Well, they eventually did, but they didn't know, and they still don't know how much (they would be left simply speculating). And they (and we) won't know until the RPVs are opened and the cores are visually inspected.

From the hydrogen and activity release, it is clear there is a lot of damage to the fuel, but a lot of damage could have occurred well below the melting point of the fuel and cladding. The cladding and channels would have oxidized considerably at half the melting temperature of the Zircaloy-2 material. Once the cladding is breached, the inner Zr-liner would have rapidly oxidized at even lower temperature, and the fuel would have been exposed to the coolant, and it would have started to oxidize. Other than the volatiles, the severely oxidized fuel would have fallen into the coolant - but it would not have melted. Only if the core had gone completely dry (essentially adiabatic conditions) would the fuel have melted.

Since water is the source of hydrogen, there had to be water in or below the core, and that would reduce the likelihood of the core melting through the RPV. It remains to be seen if the cores in units 1, 2 and 3 ended up like TMI-2's damaged core.
zapperzero
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Oct16-11, 05:13 PM
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Quote Quote by Astronuc View Post
And they (and we) won't know until the RPVs are opened and the cores are visually inspected.
Five years minimum, according to TEPCO roadmap.

Why in the name of Stinky Pete they do not just stick borescopes in there is beyond me.

Knowing the shapes and locations the fuel's in would help prevent recriticality and optimize cooling, so it's not like they would be doing it just to satisfy our curiosity.
Astronuc
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Oct16-11, 05:34 PM
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Quote Quote by zapperzero View Post
Five years minimum, according to TEPCO roadmap.

Why in the name of Stinky Pete they do not just stick borescopes in there is beyond me.

Knowing the shapes and locations the fuel's in would help prevent recriticality and optimize cooling, so it's not like they would be doing it just to satisfy our curiosity.
It's not so easy. They would have thread it though one of the feedwater lines, and then get it through the feedwater sparger, and arounound the hardware above the core. Above the core are the moisture separator and steam dryer. To go in through the top, they'd have to remove the RPV head, and before that the plug. They have no heavy lifting equipment in place to do that. They'd have to remove the steel from the upper containment first.

See the details here - http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf
NUCENG
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Oct17-11, 02:15 AM
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Quote Quote by Astronuc View Post
It's not so easy. They would have thread it though one of the feedwater lines, and then get it through the feedwater sparger, and arounound the hardware above the core. Above the core are the moisture separator and steam dryer. To go in through the top, they'd have to remove the RPV head, and before that the plug. They have no heavy lifting equipment in place to do that. They'd have to remove the steel from the upper containment first.

See the details here - http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf
IF the boroscope will fit through instrument lines, and the lines are intact, and the boroscope can survive the process conditions, and if water clarity permits, and if rad levels permit access to the penetration area by personnel to install the boroscope, there are routes to the drywell via the drywell and suppression chamber instrument lines, to the vessel outside the shroud through the vessel pressure and level instrument lines, and to the lower plenum inside the vessel through core differential pressure lines.

Navigate the IF minefield and get your camera is there and photograph the debris. Now what will you use that information for? What could you see that would change what they are doing now? They are still trying to ensure that the fuel, wherever it is, is covered and cooled to below 100 degC. Boiling keeps things stirred up and would probably be detrimental to getting useful pictures. How long was it before they inserted cameras at TMI? Is it worth the dose and risk to do this now, before completing site cleanup and building the containment "tent" structures?

I am curious, too. I "hope" they plan to look for the fuel before they start trying to remove it, but if it isn't at the top of their ppriority list right now, I can understand that, too.


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