8.9 earthquake in Japan: tsunami warnings

[Jimmy Snyder]

They would normally let the core cooldown and depressurize before opening the reactor vessel, but they lost that cooling when the lost offsite power and then the emergency diesel generators quit after one hour. It would normally be a day or so before they start preparing to unload the core. But since they lost cooling, there was no cooling down of the reactor, and it would be unsafe to try and unload the core.

Thanks Astronuc, this explanation satisfies me.

 

[jhae2.718]

Thanks for all the explanations, Astro. My knowledge of nuclear engineering is lacking, to say the least.

 

[DevilsAvocado]

The last I heard, the plant personnel were attempting to flood the containment with seawater in order to cool the reactor.

Yup:

http://www.tepco.co.jp/en/press/corp-com/release/11031301-e.html

All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down.

Unit 1(Shut down)
- Reactor has been shut down. However, the unit is under inspection due to
the explosive sound and white smoke that was confirmed after the big
quake occurred at 3:36PM.
- We have been injecting sea water and boric acid which absorbs neutron
into the reactor core.

 

[rhody]

Astro, thanks for clarifying things,

My next concern is how they will get power restored even partially with 40% of the plants not functioning, there are 6 total and 2 appear to be kaput. The others need to be inspected for damage, and repaired as soon as possible if it is safe to do so. Does anyone know what percentage of power these five reactors provide to the city and grid it was designed to serve ? Can power from other plants be rerouted to take up the slack once power is restored to what inhabitable structures remain ?

Finally, Astro, does the US possesses fuel rod technology that can in the absence of cooling water with the control rods inserted, or in the absence of control rods and cooling water to them entirely self arrest so to speak, shutting themselves down ? I was under the impression these was, please correct me if I am mistaken.

Thanks...

Rhody...

 

[nismaratwork]

The nuclear fissioning stopped when the control rods were inserted, and the reactor went subcritical.

They would normally let the core cooldown and depressurize before opening the reactor vessel, but they lost that cooling when the lost offsite power and then the emergency diesel generators quit after one hour. It would normally be a day or so before they start preparing to unload the core. But since they lost cooling, there was no cooling down of the reactor, and it would be unsafe to try and unload the core.

At shudown, the fission products are still generating heat from beta and gamma decay, and there are also some alpha-decaying transuranics. The heat is about 5 to 7% of operating power, but this quickly decays as the short-lived isotopes decay rapidly over a few days.
This provides a reasonable overview -
http://en.wikipedia.org/wiki/Decay_heat#Power_reactors_in_shutdown

I would expect TEPCO and the government to very cautious about what they reveal to the public.

In theory, they should be able to determine from certain radioisotopes whether or not the fuel in the core has been breached. Xe and Kr can be present in low levels from tramp uranium, or small breaches in the cladding. If there is Cs and Sr in the coolant, that could be indicative of fuel failures. If the detect Np-239, Ce-144 and other isotopes, this is a pretty good indicator of fuel failure.


The last I heard, the plant personnel were attempting to flood the containment with seawater in order to cool the reactor.

This shows the Mark I containment (from World Nuclear Net/GE) -
http://a4.sphotos.ak.fbcdn.net/hphotos-ak-snc6/183707_10150122455179029_53295319028_6446711_4177387_n.jpg

The will try to get water into the core which is inside the pressure vessel. I don't have any information on the integrity of the containment or the primary system, so I don't know if any of the recirculation piping has been ruptured. The steamlines go out of the upper portion of the reactor vessel, but steam line valves isolate the primary side from the turbines when the plant is shutdown.

Do you have any information about the Daikishi facility?

 

[nismaratwork]

Astro, thanks for clarifying things,

My next concern is how they will get power restored even partially with 40% of the plants not functioning, there are 6 total and 2 appear to be kaput. The others need to be inspected for damage, and repaired as soon as possible if it is safe to do so. Does anyone know what percentage of power these five reactors provide to the city and grid it was designed to serve ? Can power from other plants be rerouted to take up the slack once power is restored to what inhabitable structures remain ?

Finally, Astro, does the US possesses fuel rod technology that can in the absence of cooling water with the control rods inserted, or in the absence of control rods and cooling water to them entirely self arrest so to speak, shutting themselves down ? I was under the impression these was, please correct me if I am mistaken.

Thanks...

Rhody...

We don't use it, if we have AFAIK, but that's why I was asking Astronuc about alternative designs that use different setups for the fuel, such as a Pebble Bed Reactor (just one example of many). I can't imagine we have much new tech in our systems given the lack of political will to do anything around the issue.

 

[Astronuc]

I'm frustrated by the lack of quality information.

I imagine that the concrete containment is intact, but I have no way to verify that.

I'm puzzled by comments about the water level, which is really the critical factor here. Ideally, the core is covered to keep the fuel cool. If the core gets uncovered, then the hot (overheated) fuel can be damaged to the point of cladding breach, which is when the fission products are released.

There could be some radioactive material in the coolant which comes from corrosion products activated in the core during operation. Fuel attracts crud, which is just corrosion products of iron and nickel from normal corrosion of stainless steel. At shutdown, some of the crud is found in the coolant, but is normally collected on special filters.

The information is sketchy and that simply contributes to the uncertainty.

It would help to know when the current cycle started.

 

[nismaratwork]

"They have detected radioactive cesium, and radioactive Iodine found outside the plant."

This seems to be the cause for this concern about a possible meltdown... and now the second unit temp is rising.

"9 people have radiation exposure on their clothing... not [threat to health]"

(CNN speaking of a release from Japanese Nuclear Safety [Admin?])

2 NRC experts are on their way to Japan, and while the name hasn't been said it sounds like we've sent at least one NEST team.

http://www.cnn.com/2011/WORLD/asiapcf/03/12/japan.quake.nuclear.failure/index.html?hpt=T1

STORY HIGHLIGHTS
NEW: Some measurements may have been inaccurate, says chief cabinet secretary
"At this point, we still have not confirmed that there is an actual meltdown, but there is a possibility"
Engineers not able to see the core, but base their conclusion on isotopes in the air

 

[nismaratwork]

I'm frustrated by the lack of quality information.

I imagine that the concrete containment is intact, but I have no way to verify that.

I'm puzzled by comments about the water level, which is really the critical factor here. Ideally, the core is covered to keep the fuel cool. If the core gets uncovered, then the hot (overheated) fuel can be damaged to the point of cladding breach, which is when the fission products are released.

There could be some radioactive material in the coolant which comes from corrosion products activated in the core during operation. Fuel attracts crud, which is just corrosion products of iron and nickel from normal corrosion of stainless steel. At shutdown, some of the crud is found in the coolant, but is normally collected on special filters.

The information is sketchy and that simply contributes to the uncertainty.

It would help to know when the current cycle started.

I think the lack of information is a result of the comple interaction between the Japanese political arm of running maters, and the corporate arm (the latter is being more free with info). I'm simplifying here, but I'd trust their regulatory agency, not their ambassador. It doesn't sound as though there is confidence in any given outcome... so who wants to come out and say "meltdown", and who wants to be the one to say, "all is well"? Nobody... better for them to be vague in their view.

I find this worrying, at least, in a general sense...

 

[Astronuc]

Astro, thanks for clarifying things,

My next concern is how they will get power restored even partially with 40% of the plants not functioning, there are 6 total and 2 appear to be kaput. The others need to be inspected for damage, and repaired as soon as possible if it is safe to do so. Does anyone know what percentage of power these five reactors provide to the city and grid it was designed to serve ? Can power from other plants be rerouted to take up the slack once power is restored to what inhabitable structures remain ?

Finally, Astro, does the US possesses fuel rod technology that can in the absence of cooling water with the control rods inserted, or in the absence of control rods and cooling water to them entirely self arrest so to speak, shutting themselves down ? I was under the impression these was, please correct me if I am mistaken.

Thanks...

Rhody...

"TEPCO owns 17 nuclear reactors, 10 in Fukushima Prefecture and 7 in Niigata Kashiwazaki Kariwa, and the total capacity is 17,308 MW. Nuclear power is considered as a base load energy and it accounts for approximately 40% of TEPCO's total electricity output." Ref: http://www.tepco.co.jp/en/challenge/energy/nuclear/plants-e.html
Unfortunately, there seem to be problems with their pdfs or my version of Acrobat.

So TEPCO has other units using coal, oil and natural gas. They also have agreements with other utilities to provide power. I think one problem for TEPCO is the damage to the grid and substations. Units 4, 5 and 6 were shutdown at the time, so hopefully they could be started when needed.

The US does not reprocess spent fuel. Currently plants around the country place fuel in the spent fuel pool, which is away from the reactor and containment. Older fuel that has cooled for a decade or more can go into dry storage.

 

[nismaratwork]

"TEPCO owns 17 nuclear reactors, 10 in Fukushima Prefecture and 7 in Niigata Kashiwazaki Kariwa, and the total capacity is 17,308 MW. Nuclear power is considered as a base load energy and it accounts for approximately 40% of TEPCO's total electricity output." Ref: http://www.tepco.co.jp/en/challenge/energy/nuclear/plants-e.html
Unfortunately, there seem to be problems with their pdfs or my version of Acrobat.

So TEPCO has other units using coal, oil and natural gas. They also have agreements with other utilities to provide power. I think one problem for TEPCO is the damage to the grid and substations. Units 4, 5 and 6 were shutdown at the time, so hopefully they could be started when needed.

The US does not reprocess spent fuel. Currently plants around the country place fuel in the spent fuel pool, which is away from the reactor and containment. Older fuel that has cooled for a decade or more can go into dry storage.

I can only imagine that the most effected regions have had their infrastructure absolutely devestates... I wonder if any of these plants have a place to send their juice at all? Even if you restore the grid's transmission and transforming, you'd have so much local damage from fires and heaving ground... I'm not sure you'd do much.

 

[Dantele]

0147: The legal limit for radioactivity has been passed at the Fukushima plant, AFP says, quoting Japan's Kyodo news agency.

http://www.bbc.co.uk/news/world-middle-east-12307698

 

[aspid]

Possibly dumb question: why the boric acid, if the control rods are fully in and reactor is subcritical? If only as a precaution, it's a precaution against what risk ?

 

[caffenta]

Unfortunately, there seem to be problems with their pdfs or my version of Acrobat.

I can open them. I checked the embedded fonts and some of them are Japanese fonts, even though no Japanese characters are used (except for the author in the properties page). That's probably why you have problems. I attached the "in-depth" pdf, it's only one page.

 

[nismaratwork]

Possibly dumb question: why the boric acid, if the control rods are fully in and reactor is subcritical? If only as a precaution, it's a precaution against what risk ?

The boron in the boric acid is a strong neutron poison, meaning that it absorbs neutrons that would otherwise be absorbed by control rods, OR... in the worst case scenario, from keeping the fuel from doing the same and continuing fission.

http://en.wikipedia.org/wiki/Neutron_poison

edit:

Soluble poisons, also called chemical shim, produce a spatially uniform neutron absorption when dissolved in the water coolant. The most common soluble poison in commercial pressurized water reactors (PWR) is boric acid, which is often referred to as soluble boron, or simply solbor. The boric acid in the coolant decreases the thermal utilization factor, causing a decrease in reactivity. By varying the concentration of boric acid in the coolant, a process referred to as boration and dilution, the reactivity of the core can be easily varied. If the boron concentration is increased, the coolant/moderator absorbs more neutrons, adding negative reactivity. If the boron concentration is reduced (dilution), positive reactivity is added. The changing of boron concentration in a PWR is a slow process and is used primarily to compensate for fuel burnout or poison buildup. The variation in boron concentration allows control rod use to be minimized, which results in a flatter flux profile over the core than can be produced by rod insertion. The flatter flux profile occurs because there are no regions of depressed flux like those that would be produced in the vicinity of inserted control rods. This system is not in widespread use because the chemicals make the moderator temperature reactivity coefficient less negative.[8]

Soluble poisons are also used in emergency shutdown systems. During SCRAM the operators can inject solutions containing neutron poisons directly into the reactor coolant...

edit: Note, flooding a reactor with neutron poisons and especially sea water = the final death of this reactor. It seems unlikely to meltdown, I hope... but it will never run again.

 

[nismaratwork]

Astounding... CNN is all over this, however their information may vary...

MSNBC is playing (a re-run I think) of a prison show "Lockup"
Fox News is... wait for it... slamming Health Care a la Michelle 'Meesa one woman brain trust!' Bachman.

And we wonder why ideolgues who don't flip the channels or read are genuinely uninformed.

edit: Note: This is while a rescue is occurring live in Sendai, and new info is coming in about a possible radiological incident (or not as the case may be).

 

[Astronuc]

Possibly dumb question: why the boric acid, if the control rods are fully in and reactor is subcritical? If only as a precaution, it's a precaution against what risk ?

I suspect as a precaution. The control rods inserted, even with the strongest one left out, are designed to keep the reactor subcritical, i.e., shutdown.

If they are concerned about damage to the control blades because of high temperatures, then adding boric acid is additional insurance. If some control rods were breached, then they could lose their boron carbide due to reaction with water.

Some control rods are used during operation of the reactor, and over time, their neutron absorption capability is reduced. Boron under goes an n,alpha reaction, in which the boron (B-10) nuclear absorbs a neutron and fissions into an alpha particle and Li nucleus. That btw doesn't produce as much energy as the fission of a U-235 atom. The Li and boron can react with water. Adding boric acid simply ensures that the core is subcritical.

 

[caffenta]

Astounding... CNN is all over this, however their information may vary...

MSNBC is playing (a re-run I think) of a prison show "Lockup"
Fox News is... wait for it... slamming Health Care a la Michelle 'Meesa one woman brain trust!' Bachman.

And we wonder why ideolgues who don't flip the channels or read are genuinely uninformed.

edit: Note: This is while a rescue is occurring live in Sendai, and new info is coming in about a possible radiological incident (or not as the case may be).

To be frank, viewed from inside Japan (although I am not Japanese), I'd much rather all those sensationalism-seeking networks - CNN included - stay the **** out of it. They're like NASCAR spectators, whose main interest is to witness an accident. All they do is spread unsubstantiated bs. I guess the death count is not impressive enough. Good.

 

[nismaratwork]

To be frank, viewed from inside Japan (although I am not Japanese), I'd much rather all those sensationalism-seeking networks - CNN included - stay the **** out of it. They're like NASCAR spectators, whose main interest is to witness an accident. All they do is spread unsubstantiated bs. I guess the death count is not impressive enough. Good.

It is unfortunate, but the lack of quality reporting shouldn't be an excuse to not report at all.

 

[aspid]

Yeah, I understood that, was hoping for a softer version. I'm going on fifth grade physics here, but is there a risk of a power excursion, say if the fuel changes configuration due to a meltdown ? And the boron is there to ensure an as uniform/as much as possible neutron absorbition inside all the mess ? My attempts at logic with over-simplified hypotheses make me very worried about what's going on.

@astronuc: thanks for the more detailed explanation.

 

[nismaratwork]

Yeah, I understood that, was hoping for a softer version. I'm going on fifth grade physics here, but is there a risk of a power excursion, say if the fuel changes configuration due to a meltdown ? And the boron is there to ensure an as uniform/as much as possible neutron absorbition inside all the mess ? My attempts at logic with over-simplified hypotheses make me very worried about what's going on.

The fuel could overheat and meltdown, but there won't be a criticality event... i.e. a massive radiation release. When you're killing a reactor forever, you might as well be thorough... that's what I'm taking away from Astronuc's posts. When you SCRAM... don't go half-measures.

 

[Astronuc]

Yeah, I understood that, was hoping for a softer version. I'm going on fifth grade physics here, but is there a risk of a power excursion, say if the fuel changes configuration due to a meltdown ? And the boron is there to ensure an as uniform/as much as possible neutron absorbition inside all the mess ? My attempts at logic with over-simplified hypotheses make me very worried about what's going on.

If the fuel was damage to point where it would collapse, it would be in a less moderated configuration, so it would not become critical from subcritical. The control blades are likely still between the assemblies. The boron in the coolant just ensures that the core maintains subcriticality under any circumstance.

 

[Astronuc]

I plotted magnitude vs time since the mag 7.2 quake on 3/9/2011 2:45:20 AM.

While it would seem to have been prudent to shutdown the reactors during that period, one can see the magnitudes and frequency diminish, so there was perhaps a false sense of security. The 8.9 happened abruptly. The aftershocks include numerous quakes in the 5 and 6 mag range. They seem to be decreasing in magnitude.

The plot also includes three quakes that happened to the west or northwest of Tokyo.

There are 308 quakes represented, and it's possible that ones below mag 4 are filtered out, so there could be many more in the 2 to <4 range.

 

[caffenta]

It is unfortunate, but the lack of quality reporting shouldn't be an excuse to not report at all.

Use real news sources, not 24-hour "news" channels. Most of Japan's major papers and news outlets have English pages. They will have translations available quicker than US sources.

 

[nismaratwork]

Use real news sources, not 24-hour "news" channels. Most of Japan's major papers and news outlets have English pages. They will have translations available quicker than US sources.

In my experience, and with Japan it isn't a little experience, their media outlets are bought and paid for by political forces. I prefer to read them, watch CNN, PF, and other outlets at once, and then suspend judgement until more evidence arrives.

 

[caffenta]

In my experience, and with Japan it isn't a little experience, their media outlets are bought and paid for by political forces.

Yeah sure, but at least the source of information is closer. The 24-hour news channels will just regurgitate what Japanese outlets are saying and in the process add some garbage like "purple monkey dishwasher." I don't think any non-Japanese news outlet has any in with TEPCO, any more than NHK does.

 

[nismaratwork]

Yeah sure, but at least the source of information is closer. The 24-hour news channels will just regurgitate what Japanese outlets are saying and in the process add some garbage like "purple monkey dishwasher." I don't think any non-Japanese news outlet has any in with TEPCO, any more than NHK does.

I'd have to agree with your last statement, but remember that only sourcing your info based on proximity can lead to bias... if you're willing and able to "filter" the noise, and cultivate cognitive dissonance rather than resolving it... try my way sometime.

 

[caffenta]

While it would seem to have been prudent to shutdown the reactors during that period, one can see the magnitudes and frequency diminish, so there was perhaps a false sense of security. The 8.9 happened abruptly. The aftershocks include numerous quakes in the 5 and 6 mag range. They seem to be decreasing in magnitude.

This page has live information about earthquakes: http://www.jma.go.jp/en/quake/

You can go backwards in time to see every single quake happening in Japan. Most of the stronger ones are the 8.9 aftershocks, but some are aftershocks from the Nagano quake that occurred yesterday.

 

[nismaratwork]

http://www.cnn.com/2011/WORLD/asiapcf/03/12/japan.quake/index.html?hpt=T1&iref=BN1

This is not poetry, but it is accurate, if sensational.

Shirakawa, Japan (CNN) -- Japanese authorities are operating on the presumption that possible meltdowns are under way at two nuclear reactors, a government official said Sunday, adding that there have been no indications yet of hazardous emissions of radioactive material into the atmosphere.

The attempts to avert a possible nuclear crisis, centered around the Fukushima Daiichi facility in northeast Japan, came as rescuers frantically scrambled to find survivors following the country's strongest-ever earthquake and a devastating tsunami that, minutes later, brought crushing walls of water that wiped out nearly everything in their paths.

Chief Cabinet Secretary Yukio Edano told reporters there is a "possibility" of a meltdown at the plant's No. 1 reactor, adding, "It is inside the reactor. We can't see." He then added that authorities are also "assuming the possibility of a meltdown" at the facility's No. 3 reactor.

A meltdown is a catastrophic failure of the reactor core, with a potential for widespread radiation release.

The efforts to control the temperature of atomic material, by pumping in sea water and boron, are taking place at the same facility where four were hurt late Saturday in an explosion. Edano said only a "minor level" of radiation has been released into the environment -- saying it all came from a controlled release of radioactive steam, insisting there have been no leaks.

"We do not believe it is harmful to human health," he said...

I wish they'd be clearer that hoping for the best and preparing for the worst doesn't mean the worst is HAPPENING... still... the funamentals are accurate and up to date.

@Caffenta: Hmmm.. thanks, that's interesting.

Between you and Astronuc, we have a loooot of seimsological data.

and...

...I dont' see that it helps beyond our personal edification. I hope that this at least helps to move prediction forward... some good has to come from this.

 

[caffenta]

try my way sometime.

This is P&WA. We don't try the other guy's way. We tell the other guy that his way makes no sense and follow that with a personal attack.

Should I get my brother again? And my dad? :tongue:

 

[nismaratwork]

This is P&WA. We don't try the other guy's way. We tell the other guy that his way makes no sense and follow that with a personal attack.

Should I get my brother again? And my dad? :tongue:

Sheesh... tough broad. Don't worry, you scare me plenty without bringing relatives into this! :rofl:

edit: May I use this as a signiture? "This is P&WA. We don't try the other guy's way. We tell the other guy that his way makes no sense and follow that with a personal attack." (Caffenta, said in jest)

 

[caffenta]

I wish they'd be clearer that hoping for the best and preparing for the worst doesn't mean the worst is HAPPENING... still... the funamentals are accurate and up to date.

I think they've gone into stonewall mode.

 

[Proton Soup]

I think they've gone into stonewall mode.

it sounds like they just don't know for sure. they're simply waiting to see what happens with the cores.

 

[JesseC]

For everyone worried about nuclear meltdown, read this:

http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/

 

[DevilsAvocado]

Japans Biggest Crisis Since World War Two
Maybe more than 10,000 people killed

http://www.reuters.com/article/2011/03/13/us-japan-quake-idUSTRE72A0SS20110313

Japan tries to avert nuclear meltdown

FUKUSHIMA, Japan, March 13 - Japan fought on Sunday to avert a meltdown at two earthquake-crippled nuclear reactors, describing the massive quake and tsunami, which may have killed more than 10,000 people, as the nation's biggest crisis since World War Two.

The world's third-largest economy is struggling to respond to a disaster of epic proportions, with more than 1 million without water or power and whole towns wiped off the map.

"The earthquake, tsunami and the nuclear incident have been the biggest crisis Japan has encountered in the 65 years since the end of World War II," a grim-faced Prime Minister Naoto Kan told a news conference.

"We're under scrutiny on whether we, the Japanese people, can overcome this crisis."