Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[jensjakob]

Why do they not provide new radiation measurements since 11.10 March 17th?
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300433768P.pdf

That worries me...

 

[Astronuc]

Why do they not provide new radiation measurements since 11.10 March 17th?
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300433768P.pdf

That worries me...

24 hr cycle. March 18th report should be posted March 19th, and March nth should be posted (n+1)th.

The data is collected, prepared, reported, and QA'd. The last part hopefully, particularly if the data fulfills a legal requirement.

 

[mugaliens]

It was designed for 200 mph wind IIRC, or at least 175 mph, in order to resist the strongest hurricane or expected tornado.

No doubt with a 2.5 factor of safety figured into it, as well.

 

[jensjakob]

24 hr cycle. March 18th report should be posted March 19th, and March nth should be posted (n+1)th.

The data is collected, prepared, reported, and QA'd. The last part hopefully, particularly if the data fulfills a legal requirement.

Then this procedure began after:
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300322727P.pdf

Before that report they updated the measurements in each release. Let's watch this closely, if they also keep on posting the old numbers tomorrow, I begin to notice it for real...

 

[swimmer]

[PLAIN]http://img40.imageshack.us/img40/7456/picture2adl.png

Could anyone put a perspective on the readings of monitoring post [32] located just outside the 30km zone?

Image is from http://www.mext.go.jp/component/a_menu/other/detail/__icsFiles/afieldfile/2011/03/19/1303727_15_1_2.pdf"

Found here: http://www.mext.go.jp/a_menu/saigaijohou/syousai/1303726.htm"

 

[Astronuc]

Could anyone put a perspective on the readings of monitoring post [32] located just outside the 30km zone?

Could be a local spike, and it could be transient. Either side 31 and 33 are lower, but higher than locations further S and W.

 

[rhody]

This thought has been with me all afternoon, from the http://www.guardian.co.uk/world/2006/mar/26/nuclear.russia" above from the quote in the article:

In fact, the reactor had serious design faults: when run at low power it was dangerously unstable and difficult to control; additionally, for the first four seconds after being inserted, the control rods would do the opposite of what they were supposed to - instead of slowing reaction, they would cause a sudden power surge. Under normal conditions these faults were not regarded as dangerous; but were the reactor ever to be pushed beyond its normal limits, they could prove catastrophic.

This is an academic question probably best for Astronuc,

"What design flaw and phenomenon is this ? and what could be done (if anything) today to prevent it ?"

Second concerning http://en.wikipedia.org/wiki/Gamma_ray" , scroll down to health effects, same article:

The most biological damaging forms of gamma radiation occur in the gamma ray window, between 3 and 10 MeV, with higher energy gamma rays being less harmful because the body is relatively transparent to them.

Why is the range from 3 to 10 million electron volts so damaging to human cells ?

Finally, a little further down, same article, under Body Response, can someone address this issue please ?

When gamma radiation breaks DNA molecules, a cell may be able to repair the damaged genetic material, within limits. However, a study of Rothkamm and Lobrich has shown that this repair process works well after high-dose exposure but is much slower in the case of a low-dose exposure.

Thanks...

Rhody...

 

[Reno Deano]

This is a real nice picture of a SFP, showing the door to the reactor compartment:
http://img.ibtimes.com/www/data/images/full/2011/03/17/75371-dd.jpg

So - can one of the problems in Fukushima be that this door is damaged, and that is why they can't keep the waterlevel up?

Does not make sense, since the picture show no gate in place and the water level is up? When in refueling mode the gate can be open or closed, but the reactor vessel water level is kept up (so gate is normally open) for shielding purposes.

 

[marwood]

There is what the plant and utility have disclosed to officials, industrial and research institutions and media. Then there are officials, industry spokespersons, media and the consultants hired by those groups, or intervied in the media, and there is a mix of repeating the factual information (which could be wrong or misinterpreted) and speculation/conjecture.

Fortunately, being in the industry, I can pretty much tell when someone is bsing, or just wrong. I also know many folks within the industry in the US and abroad.

On Wednesday U.S. Nuclear Regulatory Commission Chairman Gregory Jaczko stated at a congressional hearing in Washington:
''Now, in addition to the three reactors that were operating at the time of the incident, a fourth reactor is also right now under concern. This reactor was shut down at the time of the earthquake. What we believe at this time is that there has been a hydrogen explosion in this unit due to an uncovering of the fuel in the fuel pool.
We believe that secondary containment has been destroyed and there is no water in the spent-fuel pool. And we believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures.''
http://www.nrc.gov/about-nrc/organi...-gregory-jaczko/0317nrc-transcript-jaczko.pdf

As an official, perhaps the basis for Chairman Jaczko's statement was information from TEPCO staff. According to a Wednesday noon EDT report in http://www.chron.com/disp/story.mpl/ap/world/7475743.html
begin qoute -- Emergency workers ... resumed work after radiation levels dropped, but much of the monitoring equipment in the plant is inoperable, complicating efforts to assess the situation. "We are afraid that the water level at unit 4 is the lowest," said Hikaru Kuroda, facilities management official at Tokyo Electric Power Co. But he added, "Because we cannot get near it, the only way to monitor the situation is visually from far away." -- end quote

However, since Thursday TEPCO has been focussing visible efforts on dropping and shooting water onto the No3 reactor building to add water to the No3 SPF.

NHK TV reports of a helicopter video of the No4 building suggested that TEPCO officials had identified a patch of white seen at the edge of one of the rectangular black expanses framed by the remaining concrete frame of the south part of the east side of No4 was a reflection from water in the SPF. The video was similar or perhaps the same as the link in in a previous post

What degree of confidence could a plant operator or engineer put on identification of a blurred white dot appearing for a couple of seconds in a helicopter flyby as being an adequate level of water in an SPF?

Or is the reason for the re-prioritization of No3 over No4 more likely due to inability to get close enough to No4 to do anything effective, given the comments of Jaczko about radiation levels and the TEPCO facilities manager's comment?.

 

[AtomicWombat]

Thanks for the screenshot.
Check out Wikipedia to see what kinds of levels Chernobyl had. (They had Corium flowing around that place)

http://en.wikipedia.org/wiki/Chernobyl_disaster#Radiation_levels

Vicinity of the reactor core 30,000 Roentgens/hr
Debris heap at the place of circulation pumps 10,000 Roentgens/hr
Debris near the electrolyzers 5,000–15,000 Roentgens/hr

Again, hard to tell, but I don't think we're hearing about stuff on that order of magnitude.

BOTE calculation. See here:
http://www.asianewsnet.net/home/news.php?sec=1&id=17975"

"The radiation level at the scene before the operation was 4.13 millisieverts per hour at an altitude of about 300 meters and 87.7 millisieverts per hour about 100 metres above ground."

The inverse square law would imply a 9 fold increase in radiation from 300 metres to 100 metres. Instead we see a 87.7/4.13 = 21.2 fold increase. (I am still looking for data on gamma ray attenuation in air.)

Now the inverse square law strictly only applies to a point source. We can only extrapolate to the effective cross sectional area of the source from the angle of the helicopter. Let's extrapolate to 2 metres from the source (4 square metre cross section).

If we assume 4.13 millisieverts per hour at 300 metres and no attenuation, we would estimate 4.13*(300/2)^2 = 93000 millisieverts per hour = 93 sieverts per hour = 9300 REM/hr.

If we assume 87.7 millisieverts per hour at 100 metres and no attenuation, we would estimate 87.7 *(100/2)^2 ~ 220,000 millisieverts per hour = 220 sieverts per hour = 22,000 REM/hr ~ 22,000 Roentgens/hr.

These are Chernobyl-like estimates, but they are BOTE calculations and they ignore atmospheric attenuation.

Please check my calculations. I realize these are non-trivial conclusions. I'm hoping to find an error.

 

[rhody]

To all,

What degree of confidence could a plant operator or engineer put on identification of a blurred white dot appearing for a couple of seconds in a helicopter flyby as being an adequate level of water in an SPF?

With that helicopter pilot risking and more than likely shortening his life, I have one question, WHERE ARE OUR PREDATOR UNMANNED DRONES WITH THEIR HIGH RESOLUTION 3 MILLION DOLLAR CAMERA'S. This is a no-brainer, at least for me, if ever they needed the technology, it was YESTERDAY ! There I feel better, having vented. Back to normal. Just had to vent, sorry.

Rhody...

 

[Reno Deano]

Sacramento, CA news reported today that an EPA area monitor (beta/gamma) reading in cpm had elevated readings and they associated it with the Japanese problems! They even said it was due to Cs-137 or Iodine. However, there have been no reports of increase activity of monitors from facilities further West: Livermore Labs, Vallecitos Labs, or any of the DOE or California State monitoring sites or the Nuclear Plants about similar readings.

More than likely it is a faulty monitor or just at transient spike from something else in the area.

I would rather believe almost anyone else's results before those of the EPA.

 

[Reno Deano]

To all,


With that helicopter pilot risking and more than likely shortening his life, I have one question, WHERE ARE OUR PREDATOR UNMANNED DRONES WITH THEIR HIGH RESOLUTION 3 MILLION DOLLAR CAMERA'S. This is a no-brainer, at least for me, if ever they needed the technology, it was YESTERDAY ! There I feel better, having vented. Back to normal. Just had to vent, sorry.

Rhody...

I don't think he was in any great danger (especially from radiation) other than that is normally associated with flying an apparatus that drops like a boiled egg when the rotors stop. You didn't see him flying directly over the units or through a steam cloud did you?

 

[AtomicWombat]

BOTE calculation. See here:
http://www.asianewsnet.net/home/news.php?sec=1&id=17975"

"The radiation level at the scene before the operation was 4.13 millisieverts per hour at an altitude of about 300 meters and 87.7 millisieverts per hour about 100 metres above ground."

The inverse square law would imply a 9 fold increase in radiation from 300 metres to 100 metres. Instead we see a 87.7/4.13 = 21.2 fold increase. (I am still looking for data on gamma ray attenuation in air.)

Now the inverse square law strictly only applies to a point source. We can only extrapolate to the effective cross sectional area of the source from the angle of the helicopter. Let's extrapolate to 2 metres from the source (4 square metre cross section).

If we assume 4.13 millisieverts per hour at 300 metres and no attenuation, we would estimate 4.13*(300/2)^2 = 93000 millisieverts per hour = 93 sieverts per hour = 9300 REM/hr.

If we assume 87.7 millisieverts per hour at 100 metres and no attenuation, we would estimate 87.7 *(100/2)^2 ~ 220,000 millisieverts per hour = 220 sieverts per hour = 22,000 REM/hr ~ 22,000 Roentgens/hr.

These are Chernobyl-like estimates, but they are BOTE calculations and they ignore atmospheric attenuation.

Please check my calculations. I realize these are non-trivial conclusions. I'm hoping to find an error.

More BOTE calculations, which I'll do on the fly...

http://en.wikibooks.org/wiki/Basic_Physics_of_Nuclear_Medicine/Attenuation_of_Gamma-Rays"

I'll adapt the linear attenuation model to the spherical case. Intensity is power per unit area, so the linear intensity law [URL]http://upload.wikimedia.org/math/a/0/9/a0940ee8f846fa377f8d6dc4452a4ab3.png[/URL] becomes -dP ~ P.dx.

This leads to the equation Pd = Po*exp(-mu*x), where Po is power near the source, Pd is power at a distance xd, xd - xo is distance from the source and mu is the attenuation constant in air. Dividing by area we get (Id/Io) = (xd/xo)^2*exp(-mu*(xd - x0)) and
xd - x0 ~ xd for our purposes.

Assume mu is 0.00016 cm^-1 for 200 keV gamma = 0.016 m^-1.
http://en.wikibooks.org/wiki/Basic_...Attenuation_of_Gamma-Rays#Mathematical_Model"
We want Io assuming the above info :
Io = Id* (xd/xo)^2/(exp(-mu*xd))
We already have calculation above for Ix* (xd/xo)^2: 93 sieverts per hour based on the 300 metre measuremnt and 220 sieverts per hour based on the 100 metre measurement.

So Io = 93/exp(-0.016*300) = 11,300 Sv/hr based on 300 metres metres extrapolated to 2 metres.

Io = 220/exp(-0.016*100) = 1090 Sv/hr based on 100 metres extrapolated to 2 metres.

There may be an error in my maths (done on the fly) or the assumptions about extrapolations to point sources may be way off (there are multiple sources). Also I'm not convinced I've correctly dealt with spherical attenuation and the effective cross sectional area of the source may be greater than 4 square metres.

Comments please?

 

[swimmer]

Live stream on http://www3.nhk.or.jp/nhkworld/" just reported there's TEPCO Fukushima Daiichi workers who have now received maximum radiation dose of 100mSv and that they would not be sent back in.

 

[Astronuc]

This thought has been with me all afternoon, from the summary of the Chernobyl incident post #450 above from the quote in the article:

In fact, the reactor had serious design faults: when run at low power it was dangerously unstable and difficult to control; additionally, for the first four seconds after being inserted, the control rods would do the opposite of what they were supposed to - instead of slowing reaction, they would cause a sudden power surge. Under normal conditions these faults were not regarded as dangerous; but were the reactor ever to be pushed beyond its normal limits, they could prove catastrophic.

This is an academic question probably best for Astronuc,

"What design flaw and phenomenon is this ? and what could be done (if anything) today to prevent it ?"

Basically, the responsible engineer and staff disabled the protection systems. They performed an experiment, but the parameters of the core were not in accordance with the plan (I need to go back and review the sequence). They removed a control element, and then got a + reactivity feedback due to an unanticipated source (the part I for which I need to refresh my memory). When that happened, they naturally reinserted the control elements. Now, in a graphite-moderated core, water (which is normally a moderator in an LWR) is actually a neutron poison. When the tip (not an absorber) of the control rod was inserted, it displaced the water, which removed the -reactivity, or otherwise inserted more + reactivity - and boom - the neutron multiplication took off - very quickly. In fact, IIRC, they went prompt critical, which is a BIG NO-NO!

The other effect in play with respect to cooling water in the RBMK, when the water gets hot, particularly when it boils (becomes vapor), it also absorbs less neutrons, and so that has positive reactivity coefficient. Generally, LWRs are designed for negative reactivity coefficients for moderator density and fuel temperature (Doppler) effects.

Second concerning gamma ray radiation, scroll down to health effects, same article:

The most biological damaging forms of gamma radiation occur in the gamma ray window, between 3 and 10 MeV, with higher energy gamma rays being less harmful because the body is relatively transparent to them.

Why is the range from 3 to 10 million electron volts so damaging to human cells? The higher the energy the more penetrating the gamma. 3-10 MeV just happen to have the right energy range to be penetrating, but not so penetrating that they pass through. In other words, they will penetrate and produce secondary radiation via the photoelectric and Compton effects, and even pair prodcution.

Finally, a little further down, same article, under Body Response, can someone address this issue please ?

When gamma radiation breaks DNA molecules, a cell may be able to repair the damaged genetic material, within limits. However, a study of Rothkamm and Lobrich has shown that this repair process works well after high-dose exposure but is much slower in the case of a low-dose exposure.

I'll leave that for a biophysicist.


BTW - http://news.nationalgeographic.com/news/energy/2011/03/1103165-japan-nuclear-chernobyl-three-mile-island/

 

[swimmer]

Could be a local spike, and it could be transient. Either side 31 and 33 are lower, but higher than locations further S and W.

Thank you, Astronuc. Your expertise is much appreciated.

More monitoring info can be accessed from this http://ht.ly/4exnv"

 

[Reno Deano]

Dr. Michio Kaku is a theoretical physicist, best-selling author, and popularizer of science. He’s the co-founder of string field theory (a branch of string theory), and continues Einstein’s search to unite the four fundamental forces of nature into one unified theory.

Is currently speaking on CNN live. If you can get a later video replay of it, it is a must see...especially as he speaks about the Japanese leaders (Gov't and TEPCO) being out of touch with reality. One point he makes is that that they categorized the seriousness of the reactor accidents as a "5" when that was what 3 mile island was, and it was only 1 reactor and they have at least 3 to 4 reactors in similar trouble...all at once! He recommends entombing the problem reactors now...?

Dr. Kaku may have his interview on his site soon: http://mkaku.org/home/"

 

[javadave]

Dr. Michio Kaku is a theoretical physicist, best-selling author, and popularizer of science. He’s the co-founder of string field theory (a branch of string theory), and continues Einstein’s search to unite the four fundamental forces of nature into one unified theory.

Is currently speaking on CNN live. If you can get a later video replay of it, it is a must see...especially as he speaks about the Japanese leaders (Gov't and TEPCO) being out of touch with reality. One point he makes is that that the categorized the seriousness of the reactor accidents as a "5" when that was what 3 mile island was, and it was only 1 reactor and they have at least 3 to 4 reactors in similar trouble...all at once! He recommends entombing the problem reactors now...?

Dr. Kaku may have his interview on his site soon: http://mkaku.org/home/"

Kaku is also peddling his new book right now, so who knows if he is being sensational due to other motives.

 

[Astronuc]

Kaku is also peddling his new book right now, so who knows if he is being sensational due to other motives.

I have to wonder how many non-experts are going to write books about this event.


FYI - Sequence of Events
http://www.jaif.or.jp/english/aij/member/2011/2011-03-18c.pdf


How Is Japan's Nuclear Disaster Different?
According to the author, Josie Garthwaite, Fukushima Daiichi may be no Chernobyl, but it has overshadowed Three Mile Island..
http://news.nationalgeographic.com/news/energy/2011/03/1103165-japan-nuclear-chernobyl-three-mile-island/

We await a comprehensive analysis of the activity release and exposures.

 

[rhody]

I don't think he was in any great danger (especially from radiation) other than that is normally associated with flying an apparatus that drops like a boiled egg when the rotors stop. You didn't see him flying directly over the units or through a steam cloud did you?

Reno,

No, pilot safety was only part of my concern, of course he made the flyby as quick as possible and not directly in a vapor stream. From the looks of it, he used a hand held (not HD camera to take that video). The http://en.wikipedia.org/wiki/General_Atomics_MQ-1_Predator" is capable of staying aloft for 40 hours and has a cruise speed of over 70kt.

The surveillance and reconnaissance payload capacity is 450lb and the vehicle carries electro-optical and infrared cameras and a synthetic aperture radar. The two-color DLTV television is equipped with a variable zoom and 955mm Spotter. The high resolution FLIR has six fields of view, 19mm to 560mm.

This platform can provide superior visual and thermal imagery that would be invaluable to teams on the ground assessing the situation. I would not be surprised to learn sometime in the distant future that one or more of our Keyhole spy satellite's had been directed to use it's precious maneuvering gases to overfly, sense and record the crippled reactor's in Japan. Only time will tell what if any information was gathered, analyzed and then provided to our president in his daily security brief.

Rhody...

 

[Angry Citizen]

The predator is capable of staying aloft for 40 hours and has a cruise speed of over 70kt.

You'd think the military would have hardened it against ionizing radiation to combat the effectiveness of tactical nuclear weapons, but the Predator may not have been built with that in mind. After all, the engineers who designed Fukushima's EDG system didn't consider the possibility of a tsunami. Boneheads.

 

[rhody]

Basically, the responsible engineer and staff disabled the protection systems. They performed an experiment, but the parameters of the core were not in accordance with the plan (I need to go back and review the sequence). They removed a control element, and then got a + reactivity feedback due to an unanticipated source (the part I for which I need to refresh my memory). When that happened, they naturally reinserted the control elements. Now, in a graphite-moderated core, water (which is normally a moderator in an LWR) is actually a neutron poison. When the tip (not an absorber) of the control rod was inserted, it displaced the water, which removed the -reactivity, or otherwise inserted more + reactivity - and boom - the neutron multiplication took off - very quickly. In fact, IIRC, they went prompt critical, which is a BIG NO-NO!

The other effect in play with respect to cooling water in the RBMK, when the water gets hot, particularly when it boils (becomes vapor), it also absorbs less neutrons, and so that has positive reactivity coefficient. Generally, LWRs are designed for negative reactivity coefficients for moderator density and fuel temperature (Doppler) effects.

Why is the range from 3 to 10 million electron volts so damaging to human cells? The higher the energy the more penetrating the gamma. 3-10 MeV just happen to have the right energy range to be penetrating, but not so penetrating that they pass through. In other words, they will penetrate and produce secondary radiation via the photoelectric and Compton effects, and even pair prodcution.

I'll leave that for a biophysicist.


BTW - http://news.nationalgeographic.com/news/energy/2011/03/1103165-japan-nuclear-chernobyl-three-mile-island/

Thanks Astronuc,

You are providing insight that would not possible to obtain otherwise, and since you are a mentor on here, we reap the benefit, a win, win.

Rhody...

 

[rhody]

You'd think the military would have hardened it against ionizing radiation to combat the effectiveness of tactical nuclear weapons, but the Predator may not have been built with that in mind. After all, the engineers who designed Fukushima's EDG system didn't consider the possibility of a tsunami. Boneheads.

Angry,

How can you be so sure it wasn't ?

Rhody...

 

[Reno Deano]

Live stream on http://www3.nhk.or.jp/nhkworld/" just reported there's TEPCO Fukushima Daiichi workers who have now received maximum radiation dose of 100mSv and that they would not be sent back in.

TEPCO's actions are in keeping with responsible health physics practices for emergency workers and the current situations.

Dean Chaney, CHP

 

[Reno Deano]

Has anyone seen any offsite radionuclide specific measurement data? Hand held gamma specs are dime a dozen in Japan! Every measurement team should have one. They also should have analyzed insitu air samples, by now.

 

[Astronuc]

Has anyone seen any offsite radionuclide specific measurement data? Hand held gamma specs are dime a dozen in Japan! Every measurement team should have one. They also should have analyzed insitu air samples, by now.

That's what I really want to see - the Cis of various nuclides.

 

[Angry Citizen]

Angry,

How can you be so sure it wasn't ?

Rhody...

I'm as uncertain as you are. I simply wanted to offer a possible explanation. We know a few facts. 1) Predators are dependent on a dense network of sophisticated electronics. 2) Any significant electronic interference would disrupt unshielded electronics. 3) Predators are designed to be lightweight, meaning it's possible that some engineer decided to nix shielding on account of weight or cost or some combination of the two. 4) Predators aren't necessarily designed for a nuclear-armed opponent. AFAIK, they were developed to combat guerrillas and insurgents whose technological capabilities are low, or to observe enemy positions before engagement. Radiation shielding would fall far outside necessity for such missions, since guerrillas don't tend to carry Fukushima nuclear plants on their backs, and modern warfare doesn't tend to include the risk of tactical nuclear weapons.

But I would take this analysis with a grain of salt. For all I know, the American military decided to be greedy and didn't want to risk a multi-million dollar plane. Or it's like someone else said: maybe we've got a satellite up there with sufficient imaging capabilities, but it's not being released to the public in order to keep our spy satellites' capabilities unknown (this possibility also applying to the lack of Predators).

 

[rhody]

Angry,

Look at it this way, a more perfect environment could not be had to probe your areas of concern, radiation hardness, no ?

Rhody...

 

[PoC83]

So, I was hoping someone could give me a clear answer on this because I've been unable to do so. How fast does this radiation dilute in air? Over the course of several kms what type of concentration loss occurs?