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Japan: Temperature remains high at damaged reactor(despite injection of more water)
NHK ^ | 02/07/12

Posted on 02/07/2012 5:36:50 AM PST by TigerLikesRooster

Temperature remains high at damaged reactor

An unknown rise in temperature at one of the reactors at the damaged Fukushima nuclear plant is troubling its operator. Tokyo Electric says the temperature hasn't gone down even after it increased the volume of cooling water on Tuesday.

One of the thermometers at the bottom of reactor No. 2 at the Fukushima Daiichi plant gradually rose to about 70 degrees Celsius since January 27th. It had stayed around 45 degrees before.

In an effort to lower the temperature, the operator increased the amount of water sprayed on the nuclear fuel by 3 tons to 13.5 tons per hour Tuesday morning.

But Tokyo Electric said readings were down only about 3 degrees after some 5 hours of operation, hardly showing signs of improvement.

The utility said the flow of water in the reactor may have changed after plumbing work in late January, causing difficulties in cooling part of the melted nuclear fuel.

It added that no temperature rise has been observed at 2 other thermometers in the same reactor and that it will continue to carefully monitor the reactor.

TEPCO has been unable to visually confirm conditions inside the reactors since the nuclear disaster last March because of high radiation.

Tuesday, February 07, 2012 13:05 +0900 (JST)


TOPICS: Foreign Affairs; Japan; News/Current Events
KEYWORDS: cooling; fukushima; radiation; reactor
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1 posted on 02/07/2012 5:36:57 AM PST by TigerLikesRooster
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To: TigerLikesRooster; sushiman; Ronin; AmericanInTokyo; gaijin; struggle; DTogo; GATOR NAVY; Iris7; ...

P!


2 posted on 02/07/2012 5:37:37 AM PST by TigerLikesRooster (The way to crush the bourgeois is to grind them between the millstones of taxation and inflation)
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To: TigerLikesRooster
So, you have a bunch of fissionable material sitting there fissioning away, and no longer contained within its stainless steel fuel housings ~ at a low rate of course ~ but it's still fissioning.

You take tons of water, with the requisite inclusion of some Deuterium and a small amount of Tritum, and you pump it into this mass in an attempt to cool it, and you get a surprising increase in temperature!

Is this a joke?

That's basically what you do in a few milliseconds in your typical friendly neighborhood hydrogen bomb.

3 posted on 02/07/2012 5:52:24 AM PST by muawiyah
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To: muawiyah
That's basically what you do in a few milliseconds in your typical friendly neighborhood hydrogen bomb.

It's more of a joke when a non-physicist tries to explain how something like a thermonuclear devices works.

4 posted on 02/07/2012 5:58:56 AM PST by chimera
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To: chimera
So, you explain this one smart guy.

The general outline of the fission-fusion bomb has been out there for quite a long time. The details may be missing, but we currently have SEVERAL nations with sufficient knowledge of that process to have made successful bombs.

BTW, it's an ENGINEERING PROBLEM. Most of the physics was worked out and published back in the 1930s.

5 posted on 02/07/2012 6:02:00 AM PST by muawiyah
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To: muawiyah
The general outline of the fission-fusion bomb has been out there for quite a long time.

Modern weapons use a three-stage fission-fusion-fission process.

BTW, it's an ENGINEERING PROBLEM. Most of the physics was worked out and published back in the 1930s.

No, the physics of the "classical Super" were suggested by Teller and others during the Manhattan Project. The 1930s was basic research into the fission process, measuring cross-sections, etc. There was insufficient data on cross-sections to suggest that even a fission weapon was possible until the early 1940s.

What makes modern thermonuclear weapons possible is the concept of radiation implosion. Teller signed off on the first definitive study of the physics of this process, also known as the Teller-Ulam method, in the LAMS-1230 report of April, 1951. It took about a year to implement, but even Ivy Mike in Nov. 1952 was still a kind of physics test since it used liquid deuterium instead of the lithium deuteride which forms the "fuel" in contemporary staged thermonuclear weapons.

6 posted on 02/07/2012 6:48:46 AM PST by chimera
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To: chimera
There were still some concerns about the possibility of a runaway fission process somehow igniting everything on Earth ~ right down to the day they set off a fission bomb in New Mexico.

But those were uninformed opinions ~ the physicists had long known the probability of that was very small so they forged ahead with the engineering part.

What you have here is something UNEXPECTED by the current hot-nukes guys. All they're doing is running a large volume of water (into a nuclear pile) and doing that repeatedly! Or, maybe they're just dumping it into the ocean. Do you actually know what these yahoos are doing?

Has anyone done it quite this way before? Isn't there a reason nuclear power plants use fuel that's packed in discrete amounts in precisely measured containers?

7 posted on 02/07/2012 7:05:06 AM PST by muawiyah
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To: muawiyah
*sigh*

Where to begin? Well, anyway, here goes...

So, you have a bunch of fissionable material ...

The fuel in a LWR is not "fissionable", it is fissile. It undergoes fission by absorption of a thermal neutron. Fissionable material is typically classified as something that requires a high-energy neutron to induce fission.

...sitting there fissioning away,

Other than spontaneous fission and perhaps a very small amount of subcritical neutron multiplication, there is no credible evidence of ongoing criticality in any of these reactors.

... and no longer contained within its stainless steel fuel housings

Fuel in a LWR is not contained in stainless steel. The cladding of fuel rods is zircalloy.

~ at a low rate of course ~ but it's still fissioning.

See comment above.

You take tons of water, with the requisite inclusion of some Deuterium and a small amount of Tritum, and you pump it into this mass in an attempt to cool it, and you get a surprising increase in temperature!

Far too little deuterium and tritium and in far too dilute a form to be significant for any fusion-type reactions. You need a plutonium trigger fission bomb to have sufficient energy to initiate any kind of fusion reaction. Try as you might, you are not going to get a fission detonation from any kind of LWR core, no matter how badly you damage it.

That's basically what you do in a few milliseconds in your typical friendly neighborhood hydrogen bomb.

Silly descriptors (friendly neighborhood) aside, you need far more to make a thermonuclear explosion than just bringing together uranium, plutonium, deuterium, and tritium. And the reactions in a thermonuclear detonation occur on a time scale of nanoseconds, not milliseconds. If it were milliseconds, there would be a yield comparable to chemical explosives. It is the release of a lot of energy over a very short time scale that makes for a big bang.

The first thing you need is a plutonium fission bomb. You don't have that in a LWR. Plutonium is preferred (weapons-grade, not reactor fuel grade, there is a BIG difference) because it has a higher reproduction factor than uranium. You need specially-designed tampers and "pushers", you need specially-machined radiation channels for directing the energy from the fission weapon (primary x-rays), you need a significant quantity of thermonuclear fuel, either liquid deuterium (as in Ivy Mike) or lithium deuteride. You need a pure plutonium (again, weapons-grade, not reactor fuel grade) embedded in the thermonuclear fuel. Happenstance in a damaged LWR core isn't going to produce these things, and certainly not in the form needed to initiate any kind of significant thermonuclear activity.

8 posted on 02/07/2012 7:11:17 AM PST by chimera
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To: chimera

Thank you for sharing your knowledge. Would you please sum up the risks and options for recovering a safe state in these damaged reactors?


9 posted on 02/07/2012 7:18:54 AM PST by loungitude (The truth hurts.)
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To: chimera
So, there's the answer ~ there is no heat increase!

I love it ~ you did the perfect job on deriving the correct answer (from the perspective of the hot nukes school of thought).

I'm sure the fella's at Fukushima are going to be so happy to hear it's just their imagination.

So, regarding the "zircalloy" containers ~ when they're all busted up and this stuff is just lying about being fissile, why are you pouring water on it? Like I asked, did anybody ever try this trick out before?

10 posted on 02/07/2012 7:21:18 AM PST by muawiyah
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To: muawiyah
Do you actually know what these yahoos are doing?

Yes. And they are not yahoos. They are good people doing the best they can in a difficult situation in a land that was devastated by a natural disaster. They are doing what the article said, using light water to remove heat from a material that still has a decay heat load.

And THAT IS ALL we are dealing with here. Decay heat. The materials generating the decay heat are in a geometry that is not precisely known. That makes heat transfer a difficult proposition, and modeling of the heat transfer process even more difficult. As to the temperature rise, it is explainable with much simpler and more probable mechanisms than fusion reactions. My guess (speculation, which is something generally frowned upon, but since you asked, I'll give it an honest try) is that something shifted in the cooling mass, a heat removal pathway that was previously open because blocked by debris, or perhaps vapor pressure built up enough to prevent coolant flow through an area previously receiving coolant. You see this happen all the time in other, more familiar examples. Just yesterday evening the logs in our fireplace shifted positions a little as they burned down, causing a slight increase in the radiant heat outflow. Until someone can get a visual inspection of the damaged cores, we won't known precisely what the geometry of the materials really is.

11 posted on 02/07/2012 7:21:52 AM PST by chimera
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To: muawiyah
So, there's the answer ~ there is no heat increase!

No, I never said that. I very patiently explained the physics of why there was no thermonuclear reaction occurring, which is what you suggested as a heat source.

12 posted on 02/07/2012 7:24:35 AM PST by chimera
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To: muawiyah
So, regarding the "zircalloy" containers ~ when they're all busted up and this stuff is just lying about being fissile, why are you pouring water on it? Like I asked, did anybody ever try this trick out before?

Sure, it was done after the damage to the TMI-2 core. You need more than randomly distributed fissile material and light water to initiate a fission reaction (other than spontaneous fission, which you're going to get anyway). Read up on reactor theory and the criticality equation and get back to us.

The light water is being used for heat transfer. The goal is to remove the decay heat from the materials in order to develop a plan for, first, inspecting the damaged systems, and, second, to come up with a way of recovering the materials in a way that will allow either restoration or decommissioning of the facility (TBD).

13 posted on 02/07/2012 7:29:22 AM PST by chimera
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To: chimera
No, not really ~ I was looking more at a electro-weak force explanation ~ and, in line with that you came up with the burning log ~ which is not quite there, but we're on the track.

I have no fear that any more radionuclides are going to be expelled than there ever were ~ that part of the science is certainly settled, eh! It ain't gonna' blow up, but the fellows running the show (presumably all highly trained physicists and atomic power plant engineers and designers) said the heat increase wasn't explainable.

14 posted on 02/07/2012 7:36:55 AM PST by muawiyah
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To: loungitude
Thank you for sharing your knowledge. Would you please sum up the risks and options for recovering a safe state in these damaged reactors?

Thank you. It will be a long process. The methodology is pretty well known. It will have to be implemented slowly. I am very confident the necessary operations can be conducted with essentially no risk to the general public. I am reasonably confident the people doing the work will be adequately protected, although their risk will be higher than the public due to proximity and handling of the damaged materials.

The first steps will be a visual inspection of the damaged cores to see precisely what we are dealing with. The experience we had with the TMI-2 core damage gives us a pretty good experience base as to what to expect from damaged LWR fuel (which is different than the Chornobil core). If any of it got out of the pressure vessel (if it did it likely exited through the instrument tube penetrations at the bottom of the vessel) then there will have to be a process implemented to remove that material from the containment structure.

Long-term, I don't know. It will depend on the extent of the damage. If the pressure vessels were significantly damaged, there is probably no other option than dismantling the facility. That does not mean the site could not be re-used for a power plant, but the existing structures would have to be removed.

15 posted on 02/07/2012 7:42:01 AM PST by chimera
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To: chimera

Thank you.


16 posted on 02/07/2012 7:54:27 AM PST by loungitude (The truth hurts.)
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To: muawiyah
No, not really ~ I was looking more at a electro-weak force explanation ~ and, in line with that you came up with the burning log ~ which is not quite there, but we're on the track.

The electroweak interaction is a unification between the electromagnetic and weak nuclear forces. This unification does not occur until particle interaction energies are in the range of 100 GeV, the so-called unification energy. This energy is generally not available in natural reactions except just after the Big Bang. You can get it in high energy particle accelerators, but not fission or fusion reactions. Uranium or plutonium fission releases total energy in the range of 200 MeV (MeV, not GeV). Common fusion reactions (D-D, or D-T) release energies in the range of 25 MeV per reaction. Nowhere near those needed for electroweak interactions to occur.

I have no fear that any more radionuclides are going to be expelled than there ever were ~ that part of the science is certainly settled, eh! It ain't gonna' blow up, but the fellows running the show (presumably all highly trained physicists and atomic power plant engineers and designers) said the heat increase wasn't explainable.

I think it is explainable using convention heat transfer theory, as I noted previously.

17 posted on 02/07/2012 7:57:16 AM PST by chimera
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To: chimera
Atom by atom, butt up against other atoms, and examining probabilities, there are windows of opportunity that've been known since the early 1930s.

Certainly some of the red-hot radioactive waste with short half-lives has to be doing something.

A poster up the line noted that when the Japanese point to a problem they're probably trying to hide a worse problem. No doubt we will all find out what that is over the next few months.

18 posted on 02/07/2012 8:10:22 AM PST by muawiyah
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To: muawiyah
...but the fellows running the show (presumably all highly trained physicists and atomic power plant engineers and designers) said the heat increase wasn't explainable.

I think maybe what they were saying was that they were not sure of what was causing it, or even certain it was occurring. Remember that they said they had three "thermometers" (really thermocouples) monitoring the temperature inside the pressure vessel, one showed an increase, the others didn't. That raises the question of an instrumentation problem with the one thermocouple. If it was a legitimate reading, the mechanism for the increase could be any number of things that are explainable by conventional heat transfer effects, things like blocked flow, buildup of vapor (which can inhibit conductive heat transfer), shifting of the heat-generating mass, deposition of insulating materials (debris) from the coolant flow, etc.

19 posted on 02/07/2012 8:14:15 AM PST by chimera
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To: chimera

We all must admit it’s going to be very difficult to get someone to go in there and check eh!


20 posted on 02/07/2012 8:16:50 AM PST by muawiyah
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To: muawiyah
Atom by atom, butt up against other atoms, and examining probabilities, there are windows of opportunity that've been known since the early 1930s.

While individual nuclear reactions can release significant energy at the atomic scale, you need a lot of them occurring in the same place over a short time period to get significant energy production at the macroscopic level. This was the basis of chain reaction theory developed by Meitner, Fermi and others in the 1930s. As discussed above, there is no credible evidence that uncontrolled criticality has occurred in the damaged cores.

If you're alluding to quantum effects, things like tunneling and so forth, you really need to do a calculation that relates to the probability of those things happening with the particles that are interacting. That quantity, called the expectation value, is vanishingly small for classical particles interacting at energies in the tens or hundreds of MeV range.

Aside from that, I must admit I don't know what you mean by "windows of opportunity".

Certainly some of the red-hot radioactive waste with short half-lives has to be doing something.

It was. It was decaying, releasing energy, some of which showed up eventually as thermal energy which produced other effects, fuel damage, hydrogen evolution, etc. All of this is well-known and understood from decades (going back to the 1950s) of studying the likely evolution of LWR core accidents. The thermal energy released in decay heat, while producing chemical effects and changes in the state of materials, was insufficient to approach the unification energy for the electroweak force, certainly insufficient to initiate even random fusion events. If you don't have the energy, those things simply don't happen.

21 posted on 02/07/2012 8:28:52 AM PST by chimera
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To: chimera
Other than spontaneous fission and perhaps a very small amount of subcritical neutron multiplication, there is no credible evidence of ongoing criticality in any of these reactors.

Can't we assume some criticality based on temperatures going up under circumstances of massive water infusion?

22 posted on 02/07/2012 8:30:25 AM PST by GOPJ (GAS WAS $1.85 per gallon on the day Obama was Inaugurated! - - freeper Gaffer)
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To: muawiyah
I wouldn't want to go into the pressure vessel. That will have to be done remotely. Entering the containment for extended periods should be possible once there is more decay of the longer-lived fission forms, probably a few more months.
23 posted on 02/07/2012 8:31:52 AM PST by chimera
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To: GOPJ
Can't we assume some criticality based on temperatures going up under circumstances of massive water infusion?

You can assume it, but it is likely an incorrect assumption. Criticality would manifest itself in ways other than just heat production, and those manifestations would be more immediately detectable than the thermal effects. IOW, you're going to get radiation effects a lot sooner than you are thermal effects. And there has been no evidence of these characteristic radiation effects.

24 posted on 02/07/2012 8:37:06 AM PST by chimera
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To: chimera

Thanks for sharing - interesting discussion...


25 posted on 02/07/2012 8:42:56 AM PST by GOPJ (GAS WAS $1.85 per gallon on the day Obama was Inaugurated! - - freeper Gaffer)
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To: GOPJ

Thank you. Good questions asked by all.


26 posted on 02/07/2012 8:51:47 AM PST by chimera
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To: TigerLikesRooster

Some recnt info:

http://physicsforums.com/showthread.php?t=480200&page=768

http://www3.nhk.or.jp/news/genpatsu-...207/index.html The core spray system flow rate was increased by 3 tons/hour at around 4 AM on 7 February. Total flow rate: 13.5 tons/hour. Tepco is surveying with deep care the effects of the flow rate increase over the next 24 hours or so.

http://www.nikkei.com/news/headline/...E0E2E2E2E2E2E2 :
7 February 08:00 : 71.4°C
7 February 10:00 : 69°C

http://www.nikkei.com/news/headline/...E09180EAE2E2E2 :
7 February 13:00 : 71.5°C
No xenon was detected on 7 February.

http://sankei.jp.msn.com/science/new...4230004-n1.htm
7 February 17:00 : 68.5°C (and the other two thermometers have dropped to around 41°C)

http://www.tokyo-np.co.jp/article/na...702000039.html The core spray system had been interrupted for 6 hours on 26 January in order to change a pump. Tepco says the way the water is flowing might have changed at that time, no longer reaching the areas close to the fuel as well as before. Institute of Applied Energy department head Masanori Naito said some fuel might have fallen into the RPV bottom and formed a small heap.”


27 posted on 02/07/2012 9:09:12 AM PST by mrsmith (What Tea Party nominee have you found for your House seat?)
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To: mrsmith

Sounds like the one thermocouple may have been damaged. I mounted an experiment in the ATR and one of the thermocouples showed significant drift compared to the others. I think it was a radiation effect on the thermocouple junction, although we never did any PIE to precisely determine that.


28 posted on 02/07/2012 9:19:21 AM PST by chimera
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To: chimera

Well!
As a former factory tech that info makes me think it was shifting debris.
Typically, when we did something-like remove that pump- whatever changes was caused by what we did... somehow!

Thermocouples I’m familiar with are easily changed out .
Though there could be concern that the well is punctured- or some other issue- could prevent it here of course (seems a simple task for a robot if radiation is the problem).


29 posted on 02/07/2012 9:46:10 AM PST by mrsmith (What Tea Party nominee have you found for your House seat?)
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To: mrsmith
It could be mass shifting around, no question that such is certainly plausible. As far as thermocouple change-out is concerned, it depends on accessibility. In-vessel thermocouples are usually hard-mounted in either instrument tubes or fuel assemblies. You generally don't have access to those until you do a maintenance outage, where you can get into containment and remove the vessel head. As far as I know, they have not been able to do either. Robots don't have the ability to do that kind of changeout. Too much fine manipulation. Robots cannot remove the vessel head, that has to be done manually. Accurate positioning of the lift yoke is needed. You'd spend more time installing and positioning the robots to do it than you would having people do it, and that goes against the ALARA principle.
30 posted on 02/07/2012 10:50:58 AM PST by chimera
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To: muawiyah
they're probably trying to hide a worse problem

This has been standard operating procedure for TEPCO since this all started.
31 posted on 02/07/2012 10:56:56 AM PST by freebird5850 (Of course Obama loves his country...it's just that Newt loves mine!)
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To: TigerLikesRooster
Bill Clinton advises: ...'you might want to put a little ice on that'

.

32 posted on 02/07/2012 11:15:05 AM PST by Elle Bee
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To: chimera
Widom and Larsen are probably watching this experiment in Japan ~ and are likely not going to travel there any time soon.
33 posted on 02/07/2012 12:30:35 PM PST by muawiyah
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To: chimera
Just a note: the probability of large waves occurring is a function of the number of smaller waves. Not so long ago when a ship was swamped or went down as a result of wave action people who wanted to finish out their nautical careers in peace kept their mouths shut about it.

Then, finally, the rogue waves were found, and they weren't as rogue as once thought ~ in fact, they are quite predictable ~ today we have computers analyzing satellite images to see if they are out and about.

What a change.

Now, keep that mind as we revisit your statement about ".... That quantity, called the expectation value, is vanishingly small for classical particles ....." ~ no doubt you've had to think about this in the past so what is the explanation for classical wave forms? (understanding that all those particles are themselves waves of some kind, and in various manners linked together).

Can we change the functions that create the columbe barrier in virtually any wave form? Or are we simply stuck with condensed states of matter as suggested by Widom and Larsen?

Seems to me that if we can sink a large ship with simple wave functions we should be able to stuff a proton or two inside a hydrogen nucleus, right?

34 posted on 02/07/2012 12:44:11 PM PST by muawiyah
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To: chimera
Criticality would manifest itself in ways other than just heat production, and those manifestations would be more immediately detectable than the thermal effects.

I would assume that they have some level of source range nuclear instruments functioning and monitoring each plant.

Just a thought...the recovery from this will be very long term. I wonder about the feasibility of building a new containment structure around the whole plant to assist in said recovery...
35 posted on 02/07/2012 1:02:03 PM PST by rottndog (Be Prepared for what's coming AFTER America....)
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To: muawiyah
I'm not sure the analogy is valid. Formation of ocean waves is simply a matter of fluid mechanics. Remember that quantum theory is best applied at the subatomic level. Classical mechanics works fine for the macroscopic world. It isn't that quantum theory is invalidated. Its just that its effects are more observably manifest on small distance scales. Trying to apply it at classical scales is pretty much a useless exercise, because the quantum effects become vanishingly small, at least in terms of observability.

As far as "stuffing protons inside a hydrogen nucleus", remember that a hydrogen nucleus in its most common form is simply a proton, so the "stuffing into a nucleus" becomes more a problem of simply joining another particle. This is difficult with a charged particle like another proton, but it can be done if you have enough energy. Fusion reactions that are done in things like tokamaks and the older-style stellators used D-D or D-T reactions. I used to run D-D reactions all the time in a simple linear accelerator when I was a physics student. It was a source of relatively energetic neutrons. We also ran D-T reactions with a tritiated target and a deuteron beam. That produces 14 MeV neutrons. The simplest nucleus beyond hydrogen is the deuteron, wherein a neutron is "joined" to a proton. It is just barely stable. A little bit of added energy (relatively speaking) will separate them.

36 posted on 02/07/2012 1:10:15 PM PST by chimera
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37 posted on 02/07/2012 1:23:33 PM PST by TheOldLady (FReepmail me to get ON or OFF the ZOT LIGHTNING ping list)
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To: rottndog
Well, that was what I was alluding to. You'd see those prompt neutrons right away if there was uncontrolled criticality. In a previous life I designed a criticality safety monitoring system for an enrichment facility. You had to have any number of pulse mode detectors at likely places for accumulation of fissile forms.

As far as I know the source range and intermediate range neutron monitors at all of the reactors are functional at least with enough redundancy to be able to check for low-level neutron emissions. That is how some of the initial hysterical reports of uncontrolled criticality (i.e., "blue lights", neutron "beams") were debunked. There was absolutely no indication of neutron events near the reactor pressure vessels or the spent fuel pools.

38 posted on 02/07/2012 1:25:57 PM PST by chimera
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To: chimera
Quantum theory was developed by observing very small events in discrete units of matter.

Rogue waves were found to be both identifiable and predictable through the simple expedient of watching for them from satellites orbiting the Earth.

Distance effectively reduces the scale so the quantum effects become visible ~ to wit, the towering rogue wave standing out among its brethren.

A similar approach resolved the orbit problem associated with Mercury.

The math should apply to matter manifest as waves!

39 posted on 02/07/2012 1:27:37 PM PST by muawiyah
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To: muawiyah
The anomalous precession in the perihelion of Mercury's orbit was an application of General Relativity, not quantum mechanics. Quantum theory was developed to explain effects on the atomic scale where Newtonian mechanics breaks down, in particular the "ultraviolet catastrophe", which occurs if you try to explain the motions of electrons associated with atoms in bound, stable states.

Ocean waves are explainable in terms of classical fluid mechanics. Even the appearance of "rogue waves" is simply a manifestation of the superposition principle for classic wave theory. No appeal to quantum mechanics or general relativity is necessary. It's a problem a first-year physics student can solve using vector calculus.

The wave-particle duality of matter is well known, but the effects are only noticeable on the quantum scale. Application of the de Broglie wavelength, for example, to macroscopic particles, like pieces of matter, baseballs, boulders rolling downhill, planets in orbits, gives ridiculous results. Try it sometime. Calculate, for example, the de Broglie wavelength of a bowling ball thrown down an alley. Assume a normal bowling ball of 4 kg, and a velocity of 1.5 meters/second. You'll never be able to detect that wavelength. You're better off using Newtonian mechanics.

40 posted on 02/07/2012 2:18:04 PM PST by chimera
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To: chimera
First year calculus students weren't, in fact, predicting rogue waves, particularly not when everyone in authority agreed they didn't exist, and Fur Shur, I didn't do that at the time, nor even into subsequent years.

Yet, they existed.

The probability of such a wave occurring is a higher order problem than is readily dealt with through mere reference to calculus. First, you have to believe they exist

41 posted on 02/07/2012 2:28:13 PM PST by muawiyah
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To: mrsmith
Latest speculation is that more of the fuel in #2 melted down, probably due to the plumbing changes. Reactor #2 was only reported to be about 50-60 % melted. They cannot rely on temperature guages alone. Those guages have been off by 20 C historically in this situation. There is a lot of smoke coming out of the reactor, which leads many to believe the temperature is probably closer to 85 C.

The reason they injected boric acid as a precaution was due to very low traces of fission products.

42 posted on 02/07/2012 2:35:02 PM PST by justa-hairyape
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To: muawiyah

Well, you’re getting into areas of philosophy (beliefs), and that is moving outside of the realm of the questions that physics addresses. If you want to go in that direction, it is something I am reluctant to comment on in a thread that really began as a technical discussion.


43 posted on 02/07/2012 2:41:12 PM PST by chimera
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To: justa-hairyape
Here is the latest I have on the NEI newsfeed:

"Tepco was able to discount recriticality as a potential cause of the temperature rise after conducting an analysis of charcoal filters in the containment gas control system. These showed very low traces of fission products that were below the threshold that would indicate criticality. Nevertheless Tepco this morning injected boric acid into the reactor vessel as a precaution and increased the core spray injection rate by three cubic metres per hour."

The overall core temperature remains within the limits specified for cold shutdown (less than 100 deg. C.).

44 posted on 02/07/2012 3:53:22 PM PST by chimera
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To: chimera
The correct wording from TEPCO, I believe was that they were injecting boric acid to prevent the increase in the non-measurable fission products. You have to pay very close attention to how they word things, unfortunately.

Here is how the nuclear industry is reporting the situation.

Tepco was able to discount recriticality as a potential cause of the temperature rise after conducting an analysis of charcoal filters in the containment gas control system. These showed very low traces of fission products that were below the threshold that would indicate criticality. Nevertheless Tepco this morning injected boric acid into the reactor vessel as a precaution and increased the core spray injection rate by three cubic metres per hour.

Stabilisation after Fukushima cooling change

So it was not no detectable fission products. Again, you always need to know the limits of detection for every Tepco reported value. It was measured fission products that were determined to be below the thresholds that would indicate fission. Now how they determine the thresholds for an unknown situation is beyond me. And that is probably why they added the boric acid.

45 posted on 02/07/2012 4:34:56 PM PST by justa-hairyape
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To: justa-hairyape
Oops. Just noted that was your exact quote. Mine has a source link. So my problem with the nuclear industry, ever since Fukushima has gone boom, is with the obfuscation about the facts. If they knew without a doubt, that there was no fission levels to worry about, they would not have added boric acid.
46 posted on 02/07/2012 4:39:43 PM PST by justa-hairyape
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To: justa-hairyape
If they knew without a doubt, that there was no fission levels to worry about, they would not have added boric acid.

It was stated that it was done as a precaution. What is the reason for the precaution? Probably two reasons, one technical, the other political. The technical reason is that if there is material shifting around, it can change the geometry in ways that are not fully characterized. One of the principles of criticality safety is to go the extra mile to assure that you have inserted negative reactivity to offset any possible increase in reactivity as a result of the geometry change. The political reason is that if they didn't do it, the anti-nuke kooks would accuse them of not taking proper precautions.

Once the new geometry has stabilized, they will likely reduce the boric acid concentration gradually and check to be sure criticality is not being approached. That is a very straightforward reactor physics measurement involving subcritical multiplication. One of the classes I teach does the very same measurement, not by boron concentration but by control rod positions. It is called incremental approach to critical. You get extremely precise measurements of critical rod position. Same deal with born concentration.

47 posted on 02/07/2012 6:34:48 PM PST by chimera
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To: chimera

Can understand that, but it has been reported that they ended up adding 1,094 Kg of boric acid. More then they originally estimated would be required. That does not seem to be a well calculated preventative maintenance procedure done partially for show.


48 posted on 02/08/2012 12:41:24 AM PST by justa-hairyape
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To: muawiyah

Would huge ice cubes work at cooling better than water? Just wondering....


49 posted on 02/08/2012 12:45:32 AM PST by goat granny
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To: justa-hairyape
1094 sounds like a lot of mass, but you have to remember basic chemistry and physics. First, remember that the chemical formula for boric acid is H3BO3. That means that only 18% of the weight of the molecule is boron. Next, remember that only 20% of the boron is of the strongly neutron-absorbing form, 10B. That means of the total 1094 kg of boric acid, about 3.5% of that mass, or about 38 kg, was of a form that strongly absorbs neutrons. When you consider the volume of the pressure vessel, or even the volume of the mass they are trying to affect, 38 kg of material spread over that isn't a terribly large amount. If it was more than originally expected, my guess is they wanted to be conservative on the chance that some of the water carrying the material might evaporate or be diverted through the complex geometry without reaching all of the places they wanted it to get to if they used less.

Now, as Obamalamadingdong would say, here we have a teachable moment. We are better if we first consider the science and run the numbers before we jump to emotional conclusions (1094 kilograms is a lot of mass, more than they expected, therefore they must be lying, putting on a show). While doing so may be emotionally satisfying because it validates a personal prejudice, it can lead you away from the truth.

50 posted on 02/08/2012 7:23:06 AM PST by chimera
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