Japan's Nukes Following Earthquake

[Rennhack]

I've been contacted by the USA Today, and the BBC... they want to talk to Nuclear workers.  If anyone wants to talk to them, email me.  I'll give you their info.

[MacGyver]

I've been contacted by the USA Today, and the BBC... they want to talk to Nuclear workers.  If anyone wants to talk to them, email me.  I'll give you their info.

Those of you that choose to do this PLEASE be careful.  My company fired an employee yesterday due to making commits on the radio.  Most company's have strict policy's regarding this type of behavior.

Just saying .. Be careful.  Or turn them over to your Public Relations / Media Department.

Mac

[Roll Tide]

I would recommend only those not currently employed (e.g. waiting on outage season to start) volunteer for an interview.

Oh, and BZ! 

[retired nuke]

my only experience with exposed spent fuel - 

a single, partial fuel pin (~ 70% of it) from a multi-cycle old bundle (one rod from a bundle) used in the outer position in the core at ~ 37 feet (top of cavity to bottom of transfer canal) is about 1R/hr.

I imagine that a pool full of spent fuel, slowly uncovered due to evaporation, would hit the hard to measure level pretty hard.... 

[PJMcG]

Does anybody know if the spent fuel pool (SFP) level problems are related to structural damage or simply accelerated evaporation rate due to the loss of SFP cooling?

http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300350525P.pdf

!!!!!!!!SPECULATION ALERT!!!!!!!

For the first day or two, the spent fuel problem seemed not to be an issue, then suddenly it became the most significant problem.  That leads me to believe that this wasn't merely evaporation, but COULD (and i emphasize COULD) have been damage as a result of the adjacent unit hydrogen explosion and the reported fires in the unit 4 SFP vicinity.

If there is structural damage to the SFP AND it is below the top of the fuel, they will need a makeup system that is of greater capacity than the leak rate.  Additionally, they will have to manage the leakage.  Obviously the first priority is to get the fuel covered and these other considerations are secondary, but they should be on the minds of the engineering team that is supporting the Fukushima Fifty.

!!!!!!!!END SPECULATION ALERT!!!!!!!

I look forward to reading your thoughts and insights and I continue to pray that the sustained heroic actions of all those on site are successful.  In the end, logic, reason, and science will prevail ... but we could use some divine intervention here as well.

PJ

[Nuclear Renaissance]

Does anybody know if the spent fuel pool (SFP) level problems are related to structural damage or simply accelerated evaporation rate due to the loss of SFP cooling?

http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300350525P.pdf

!!!!!!!!SPECULATION ALERT!!!!!!!

For the first day or two, the spent fuel problem seemed not to be an issue, then suddenly it became the most significant problem.  That leads me to believe that this wasn't merely evaporation, but COULD (and i emphasize COULD) have been damage as a result of the adjacent unit hydrogen explosion and the reported fires in the unit 4 SFP vicinity.

If there is structural damage to the SFP AND it is below the top of the fuel, they will need a makeup system that is of greater capacity than the leak rate.  Additionally, they will have to manage the leakage.  Obviously the first priority is to get the fuel covered and these other considerations are secondary, but they should be on the minds of the engineering team that is supporting the Fukushima Fifty.

!!!!!!!!END SPECULATION ALERT!!!!!!!

I look forward to reading your thoughts and insights and I continue to pray that the sustained heroic actions of all those on site are successful.  In the end, logic, reason, and science will prevail ... but we could use some divine intervention here as well.

PJ

It would appear that it would have to be due to sturctural damage / draining, if low pool levels indeed exist for Unit 4 (the US NRC believes it so). Day-to-day visuals have never shown any boiling from the area around the refuel floor.

XF said it earlier, the success path may very well be injecting via the reactor cavity and spilling over into the pool. CRD is probably the easiest to align if 200 gpm outpaces any leak. Core Spray and RHR would be larger-capacity options, with CS probably already aligned to an external source. All pumps are in the basement of the RB, where dose would be lowest, except for the injection valves, whose manual operation could result in dose complications if the pool is in fact drained.

[Marlin]

   Dose rates will be high at the fuel pool edge making access difficult, but not impossible. Fuel bundles at some point decay to a level of thermal generation where they are stored dry without any cooling, these bundles are not to that point obviously but are not fresh out of the core so some decay has occurred. Most of the bundles in the pool are likely from previous fuel cycles and are significantly more decayed than the ones from the last cycle which I assume is 1/4 to 1/3 of the total number of bundles in the core (operators comment?).
  There was talk today about dropping water into the spent fuel pool by helicopter. I heard conflicting reports on whether or not the spent fuel bundles were covered or not. As long as the fuel bundles contain the contaminates the dose rates even as high as they have become would be a site problem primarily. If the bundles are dry and water is dropped on them I would think that there is a potential to damage whatever integrity is left in the bundles. The physical shock from the drop would be damaging, water is not light and the height would provide a lot of force. Thermal shock to already stressed tube in the bundle would further weaken it. And finally the chemical reactions that would also further weaken the tubes. Though decisions!!!
  These are my observations and speculations, who knows what the real story is until this is over. Communication to the public always seems to suffer a bit during any major disaster world wide, but then the experts (those on site) hopefully are busy with the problem not public relations leaving us to speculate.

  These operators, technicians, and engineers have an awful lot on them. Under the conditions they are working I can't help but to admire those who volunteered to stay.

[Matthew B]

If the pool is down to the top of the fuel, let alone below the top of the fuel, the dose rate in the air directly over the pool would be phenomenal.  No doubt the helicopters used for water dipping would have dosimetry on board.  Even at 1000 feet up they'd know for sure if the pool is close to drying out.

[Matthew B]

I'm trying to remember where I saw the information on the fuel cycles for each unit.  I'd like to point to a link rather than using my fuzzy memory.  IIRC, unit 1 was at 11 months since refuel and unit 4 was down some 150 days due to inspection work.  I think units 2 and 3 were at the same as unit one but I'm less sure of that.

[hamsamich]

Speculations/Questions about Unit 4:

If the fuel can't be cooled and continues to burn, will it eventually melt/disentigrate the bottom of the fuel pool and fall into the upper levels of the Rx Building?

Should/could a solid material (like concrete or sand mixed with poisons) be poured into the fuel pool if the fuel pool integrity can't be maintained enough to feed and bleed water?  Could this possibly plug some holes long enough to keep water in long enough to cool the fuel?

Also, I'm thinking access to the edge of the Pool right now would most likely be deadly in less than an hour due to radiation exposure, let alone fire/particles/building integrity; do others agree?

[MM1 subnuke]

I have sent the following email to the local media outlets here in Houston, hopefully it will get someones attention and they will sue this site to gain a better understanding of what is going on over there.  Thanks to all of you guys in the know for keeping us abreast of what is really going on (educated guesses anyways).

"Hello, I wanted to contact you to give some advice and hopefully some useful information regarding the Nuclear "Crisis" in Japan.  I use that term "Crisis" loosely as should you due to the lack of true information available at this time.  Just some quick background on me to help you understand the validity of information I am passing along.  I worked in the Navy for 9 years as a Nuclear Machinist Mate.  What that means is this, I worked as a primary and secondary plant operator in our Nuclear power plant aboard different submarines.  I have a few years of experience with nuclear power and as such have a better understanding of what the actual situation means for the rest of us.  With all of that I said here comes the advice, most of the media outlets, yours included, are giving out information that is not necessarily false, but provides a false sense of "impending" doom for the residents of this country, specifically for those of us near operating nuclear reactor plants.  There are not enough details to fully diagnose the situation, and as such a recommendation would be not to do so.  However, if you must, I would STRONGLY recommend using this site as a reference, and possibly putting it out for the public use to gain a better understanding of what is actually taking place and what the true outcomes are and may be.  http://www.nukeworker.com/forum/index.php/topic,26998.420.html  This particular link is an ongoing discussion about the Japanese Nuclear disaster and the "Educated Guesses" of what is going on over there.  I say this most likely on the behalf of many of my Nuclear brethren, please get educated about nuclear power and its safety.  "

[PJMcG]

http://online.wsj.com/article/SB10001424052748704662604576202424107906298.html?mod=WSJ_World_MIDDLENews

Quote from Japanese Govt regarding SFP at Unit 4:

"Government officials say they can still see water in a pool containing spent fule rods in the No. 4 reactor."

I didn't see a timestamp on this quote nor who stated this.  The interactive graphic at WSJ does narrow it down to March 'Today' (i.e., March 17, 2011).

[PJMcG]

Video from helicopter:

https://www.youtube.com/watch?v=lBXqiw6EJUk

This is very shaky, but if paused in places gives some of the 'best' views of the Fukushima Daiichi site yet.

PJ

[MM1 subnuke]

I don't know if I would say that his approach is needed at this point though.  The "Cherynoble" approach as he calls it will make that whole area and the surrounding one off limits for many, many generations, and then you have to "hope" you aren't having a melt through of containment into the water table.  I say that all based on what we little info we have, maybe it is worse than I believe at this point, and now is the time to "entomb" these units before we cannot without killing the pilots.

[hamsamich]

Info on helicopter used in this disaster.

CH-47J is a medium-transport helicopter for the Japan Ground Self-Defense Force (JGSDF), and the Japan Air Self-Defense Force (JASDF).

28,000 lb (12,700 kg) cargo

[jongular]

Here is another update on the situation and exposure rates:

http://nuclearstreet.com/nuclear_power_industry_news/b/nuclear_power_news/archive/2011/03/17/focus-at-fukushima-daiichi-now-on-spent-fuel-tanks-as-helicopters-and-water-cannons-work-to-quench-unit-3-_2800_with-reactor-status-list_2900_031704.aspx

Now I'm not that familiar with Sv and mSv, but rates of 87.7 mSv at 300 ft definitely show a large problem.

1 Sv = 100 rem
1 mSv = 100 mR (mrem)

I believe is the correct conversions.


Great posting by everyone so far. Keep the information coming!

[Nuke of the North]

Finally, the media found an expert with a clue...

http://www.msnbc.msn.com/id/21134540/vp/42130567#42130567

Is this the Michio Kaku video linked on the MSNBC front page (I can't view it due to the firewall here)?

I've always liked Dr. Kaku - I still do - but he has a very clear anti-nuke agenda, and he's smart enough to parse his words in a such way to make his opinion sound irrefutable (to the casual observer) on the issue.

[hamsamich]

so with quick radcon math, at those two distances, it is acting like a point source on crack (obviously it would act like a plane source much closer)  I know these are rough estimates.  Good to know some values.

"Two helicopters made four attempts to drop water into unit 3 with mixed success. Radiation readings taken from a smaller helicopter beforehand indicated levels of 4.13 millisieverts per hour at 1,000 feet above the unit and 87.7 millisieverts at 300 feet. Although crews were equipped with protective gear, radiation levels limited the amount of time the helicopters could work in the area, and they did not hover directly above the unit."

[Cycoticpenguin]

Assuming a big plane source and assuming that these helicopter readings are correct, radcon math sez we got about 80 R/hr at 100 ft with 200-500 R/hr on the ground depending on source size and a host of other variables.  Of course, the only way to know for sure is an HP with a teletector or similar instrument.  I'm sure there would be some hot spots that would peg the tele at 1000 R/hr.

Based on the "helicopter" report, I would have to agree with the Chernobyl approach at this point...of course, only the people on the ground know for sure.  Based solely on the "helicopter" report, it looks like we have an INES Level 7 Major Accident brewing and we are in denial, which is not just a river in Egypt.

However, I just heard another report, which is contrary to the "helicopter" report.  I have heard that it is 300 microsieverts/hr at the gate, which equates to 30 mrem/hr and the fuel is covered.  Based on this report, everything is under control (relatively speaking of course).  Only the people on the ground really know for sure....let's hope the helicopter report is wrong.

thats kind of an issue right now. I read an article that first said "micro" seiverts, then in the same article it said "milli" seiverts. Two VERY different numbers obviously...


I dont understand why they are trying to "save the situation" anymore. Isnt it time to bring out the lead and steel? Even with 1000R/hr radiation level a fifteen minute drop from a helicopter would only be 166 R. (yes "only", I get it). Last I checked 166 Rem acute dose would be a somatic effect and prognosis would be good (95%+). Even then, 1000R/hr at the pool wouldnt be what they would get in a helicopter. EPA limit is 75 rem for lifesaving, does preventing a massive release of radiation count towards this?

[Marlin]

   We keep hearing dose rate over the facility. We know that there is some air borne as some of our sailors came back with minimal contamination, I am more than a little curious about how much is shine from the plant and how much is immersion dose from a plume if any? Still looking if anyone sees this please post.

[PJMcG]

I also think that Dr. Kaku is premature in calling for the sarcophagus.
Additionally, there is a flaw in his logic, if the radiation levels are too high to either dump water from helicopters or to spray into the buildings via water cannon ... how are they supposed to get sand, cement, and boron into the reactor buildings without incurring similar or higher doses?
I would suggest bomb squad robots with cameras, radiacs, and dosemitry for the initial inspections and depositing battery powered video cameras for surveillance. 
The sarcophagus also is a de facto resignation to abandon in place as opposed to a stabilization followed by long term disassembly in place over a matter of years; as they did at TMI-2.  We can learn much more about severe accident mitigation and apply those lessons to future operation and design.  Some of you may remember Admiral Rickover's response to a fuel element failure on a (I think 585 class) submarine – (I'm paraphrasing) continue to operate it and monitor its degradation over time.  Essentially, we'll hopefully never have another opportunity like this from which to learn, but we have it so let's make the best of it.  Let me be clear, that none of us wanted an accident of this magnitude to ever Ever EVER occur – but it did and we must deal with the consequences rationally and responsibly.
One of the problems with current reports is that we hear lots about radiation levels, but little about contaminated material (i.e., mass , activity, or radio isotopic content) releases.  In fact most of the talking heads don't seem to understand the difference.  I have seen no information about air particulate samples that would yield some concentration data to extrapolate radioactive material (mass, content, and activity) releases and better estimate fuel damage in the cores of Units 1, 2, and 3, and in the Units 3 & 4 SFP .
We may get to the point where the sarcophagus is the best choice.  But I don't think we or a professor in a news studio with continents and oceans between us and the scene have sufficient information to make that decision.  We have an obligation to contemplate and discuss it, but only those with the responsibility, authority, and accountability can make that call.  Godspeed to them. 

[Cycoticpenguin]

PJ -> The opportunity to learn is great, but what point do we call enough, enough? Theres only so much we can learn from an exposed fuel pool... The reactors are useless now, so why not bury the fuel rods to prevent further release?

[matthew.b]

One of the problems with current reports is that we hear lots about radiation levels, but little about contaminated material (i.e., mass , activity, or radio isotopic content) releases.  In fact most of the talking heads don't seem to understand the difference.  I have seen no information about air particulate samples that would yield some concentration data to extrapolate radioactive material (mass, content, and activity) releases and better estimate fuel damage in the cores of Units 1, 2, and 3, and in the Units 3 & 4 SFP .

The anecdotes point towards a high level of shine and a low level of contamination release.  That would point towards the fuel being exposed but not much damage.

[hamsamich]

okay I'll give it a shot to get the ball rolling.  smite and catcall away!

calling r-eff 25ft, and calling the DR 6r/hr at 300 ft, I'm getting somewhere around 10,000 r/hr next to the pool.  Lots of guessing and assumptions here.  Anybody ever taken a doserate on a dry fuelpool with tons of irradiated fuel in it?

[PJMcG]

Murph,

That is a great question, maybe the only truly urgent question.  When is enough - enough?  As I stated, we don't have sufficient information to make that call; however, I also acknowledge that we may be there already.  Moreover, a healthy and honest debate on the subject will hopefully raise points of consideration that each of us left alone may not have identified.

What can we learn by delaying or avoiding adding boron, sand, and cement?
1.    How much fuel damage has occurred under these conditions?  In each of the three reactors and the uncovered SPF?  We know it's bad, but precisely how bad?
2.   Under these conditions is full meltdown avoidable? 
  a.   Did it happen?
  b.   How did vessel internals respond?
  c.   What design modifications should be implemented moving forward? 
  d.   Are current ABWR, ESBWR, and AP1000 designs sufficient under a similar scenario?
3.   Are current design basis accidents sufficient?  If not, what specific other considerations should be factored into new designs and retrofitted into existing operational fleet.
4.   What additional retrofits should be made to existing Mark I containment systems?  (Richter 9, 10, 11?  8, 9, 10 meter tsunami?)
5.   Should plants with Mark I containments by decommissioned?
6.   Is there a lower limit to the amount of fuel that should be stored in the spent fuel pool than is currently practiced?  I would argue that fuel reprocessing will reduce the amount of high level radiation and reduce the amount of spent fuel that is accumulating at reactors the world over.

Are there downside risks to proceeding with entombment today?
1.   How would a six (maybe eight) reactor facility entombed in concrete respond to seismic activity and subsequent tsunami?
2.   Will a cement, sand, and boron reach all areas intended to be entombed?  Or will we be left with a constantly leaching radioactive semi-porous block of concrete at the water's edge?
3.   How will the necessary materials be transported to the site?
4.   How much of each will be required?
5.   At what mixture should the materials be injected?

I know there are more questions than answers now and that some of these questions can be partially answered going down either path.  They don't clean up crime scenes before the evidence has been collected and preserved.  We will undoubtedly learn more if we are not forced to entomb these plants and SFP.  However if entombment is the rational decision after careful consideration, then that is how we should proceed.

I welcome the challenge Murph, we're better collectively through the respectful exchange of ideas.

[Note: I bounce back and forth between first person singular and first person plural – I can't help but feel a part of this and I'm filled with sympathy and empathy for all lives affected by this truly horrific tragedy.]