Continuing nuke crisis in Japan

Written By: Marty G - Date published: 10:40 am, March 16th, 2011 - 63 comments
Categories: disaster - Tags: japan, nuclear energy, sendai earthquake

Every day brings a new disaster from the Fukushima No 1 nuclear power plant. Four reactors have now experienced an explosion and/or fire and/or partial meltdown. Yesterday saw the first significant radiation release, from Reactor 4. It’s a complex situation, so I’ve tried to summarise it as it stands this morning.

Reactors 1 and 3, you’ll recall, experienced hydrogen explosions after gas that had been created, it seems, by fuel rods partially melting through their coverings and coming into contact with the water inside the reactor cores. This hydrogen, along with steam, was pumped into the outer containment building, where it exploded, ruining the buildings but, it seems, leaving the reactor cores intact. The situation with these two reactors seems to be under control. Sea water and boron have been pumped in to replace the water that had been turned to steam and dissociated. Using sea water was a desperate last ditch effort that will corrode the reactors to the point they can never be used again, which gives you some idea of the severity of the situation the operators were facing, but it seems to be working. I haven’t been able to find out what happens to the sea water after it has been used to cool the reactor – presumably it can’t be released back into the sea.

Reactor 4 had been offline for maintenance (along with reactors 5 and 6) when the earthquake and tsunami struck, so, unlike reactors 1-3, cooling off the core without power to pump the water around was no problem. But something went wrong with the storage pond where spent fuel rods are kept. It seems that the explosion at Reactor 3 may have damaged Reactor 4’s containment building, exposing the storage pond to the air. Steam was seen rising from this pond, apparently from the spent fuel rod’s heat, then there was an explosion (cause unknown) and a fire. A fire is the last thing you want around fuel rods because it can break them up and carry the debris into the atmosphere, dispersing the radioactivity.

The events at Reactor 4 sent radiation levels in the immediate vicinity to four times the level where radiation starts to affect human health. That isn’t a death sentence for the workers in the area, as long as they don’t stay there too long, but it was enough to prompt the evacuation of 750 staff leaving just 50 doing to seat water pumping operation. Elevated but safe radiation levels have been detected in Tokyo, over 200km away. Radiation levels reportedly fell soon after the initial explosion. The plan is to drop sea water from helicopters into Reactor 4’s containment building, putting out any fires and absorbing radiation from the spent fuel rods.

The one that looks like the real worry is Reactor 2. The water pressure in its suppression pool suddenly dropped after an explosion within it was heard, suggesting it has a leak. The suppression pool is (if I’ve read Wikipedia correctly) meant to take energy and radioactive elements out of the steam released from the reactor before it goes into the outer containment building. If the pool can’t do its job, the amount of radiation absorbed is less and the pressure that can be relieved is less and, instead, it builds up, potentially causing an explosion. The NHK coverage yesterday was describing the suppression pool as the ‘last line of defence’ against a radiation release in the event of a full meltdown. Reactor 2 is also having sea water pumped into it but with the suppression pool damaged, this may not work as well.

The difference between this situation and Chernobyl is the multiple layers of protection around the radioactive materials but we have seen all but one of them fail in some instance. Fortunately, none of the meltdowns seem to have been severe enough to break through the thick metal walls of the reactor core itself but given all the other failures, I won’t be breathing easy just yet.

63 comments on “Continuing nuke crisis in Japan ”

Comments are now closed

Tel 1

16 March 2011 at 11:05 am

I think a more accurate summary is SNAFU.

The US-based Institute for Science and International Security is in agreement with France’s Nuclear Safety Authority saying Fukushima should be classified as level 6 on the International Nuclear Event Scale. What is completely clear in this event is the absence of reliable data. Even the Prime Minister Naoto Kan is not fully in the loop according to media reports.
Anti-spam word: factor 😕
RedLogix 2

16 March 2011 at 11:09 am

My gut feeling is that if nothing else major goes wrong today they should just scrape through this without a total catastrophe.

If the radiation levels at the plant become too severe to be survivable… then it will be game over. But truly we have to think that will not happen.

Most of all my thoughts are with that handful of 50 engineers and techies left on site to battle this crisis with heart and soul. I really want them to win.
- Colonial Viper 2.1
  
  16 March 2011 at 11:15 am
  
  The world needs those 50 engineers and techs left to win. Regardless of the end result, they and each of their families should be fully recognised and cared for after this event.
  
  Anything other than a win would be a horrible horrible result for the tens of millions of people who live within 1000 km of Fukushima.
  
  However I think that the time of danger for the plant extends out over the next several weeks. The fuel in the reactors and the spent fuel in the cooling ponds will need constant care and attention over that time until further steps can be taken to remove/entomb the nuclear material.
  
  I can’t believe that I heard reports that one of the spent fuel ponds ran dry because the fire appliance pumping water in *ran out of fuel*. OMG.
  
  Also a Russian expert said that it was clear that saving money had been a factor in putting so much spent fuel so closely together in relatively small containment ponds.
  
  Overall I’m keeping every finger and toe crossed for those in Japan.
- Lanthanide 2.2
  
  16 March 2011 at 11:17 am
  
  Presumably the high radiation being measured is at close proximity to the cores, where the workers probably aren’t. They’re probably also in buildings designed to minimise radiation exposure, and probably also wearing protective suits. With any luck they shouldn’t see any fatalities or serious sickness from their exposure.
Lanthanide 3

16 March 2011 at 11:23 am

In general it’s been quite difficult to keep track of developments as they happened on the 15th, both due to the fast pace of events and the fact that multiple of the same events keep happening but at different reactors. The media’s general ineptitude when it comes to anything seriously scientific as well as their insistence on dramatising everything with an anti-nuclear bent doesn’t help. The media also likes to recycle earlier statements and interviews from experts and scientists, even though the situation may have substantially changed since they first gave their statements.

“I haven’t been able to find out what happens to the sea water after it has been used to cool the reactor – presumably it can’t be released back into the sea.”

From my understanding, the water that is being pumped in is going directly into the reactor vessel itself, basically flowing around the fuel rods (that’s what the boron is for – to help absorb neutrons). As there is significant heat in there, the seawater will be turning into steam, so presumably they are periodically (like maybe every 30 minutes?) releasing steam out into the environment. As the steam is filtered/scrubbed and most of the radioactive isotopes stay behind in the liquid water, this doesn’t pose too serious of a radiation risk.
- RedLogix 3.1
  
  16 March 2011 at 11:32 am
  
  I have to agree… there has been an enormous amount of conflicting information and getting a coherent sense of what is current and what is not, is very problematic.
  
  So far however it seems that someone at Stuff is doing a good job on their updates.
  
  And sadly, if I’m reading it right, it looks like the fuel storage area at #4 is on fire again… and this time radiation levels are too high to approach it.
  
  http://climateprogress.org/2011/03/14/third-explosion-reported-3-cooling-systems-failing-3-meltdowns-cant-be-ruled-out-spent-fuel-risk-also-great/
  - Lanthanide 3.1.1
    
    16 March 2011 at 11:41 am
    
    Yeah, the ‘recent updates’ on Stuff is good, although very brief most of the time. The actual articles on stuff leave a lot to be desired however, and because they’re often out of date compared to the ‘recent updates’ gives people a very conflicted view of what’s going on.
    
    You also would’ve seen “spewing radiation” all over the headlines yesterday. It seems Reuters (or AP?) came up with that and everyone else copied it.
  - toad 3.1.2
    
    16 March 2011 at 11:47 am
    
    Yes, that is not good news RL, although this report says firefighters are attempting to contain it..
  - Lanthanide 3.1.3
    
    16 March 2011 at 12:35 pm
    
    Reading that, and the linked schematic is really quite worrying.
    
    “At the 40-year-old Fukushima plant, which was built by General Electric, the fuel rods are stored at a pool about three stories up, next to the reactor (a schematic is here). Satellite photos raise concerns that the roof of the building housing the pool has been blown off”
    
    “Satellite photos appear to show that two cranes used to move spent fuel into the pool “are both gone,””
    
    You can see the schematic diagram here: http://allthingsnuclear.org/post/3824043948/update-on-fukushima-reactor
    
    It seems these pools are open-air and only protected by the secondary concrete containment building. This seems completely inadequate – if terrorists hijacked a plane and flew it into that building, there’s no way that such a lightly protected pool of radiation wouldn’t be exposed to the environment. A large earthquake that involved significant ground movement on the site could cause problems, or even an unlucky meteor strike could result in Chernobyl-style disaster.
    
    Looking at that, I can really identify with anti-nuclear campaigners. My objection however wouldn’t be that “nuclear power is unsafe”, it would be that “nuclear power plant designs are inherently danger-prone for no good reason”.
    - todd 3.1.3.1
      
      16 March 2011 at 9:58 pm
      
      The #4 reactor was supplied by Hitachi with the architecture by Hitachi and constructed by Kajima… Kajima constructed all 6 units. General Electric supplied the reactors of 1, 2 and 6 (the largest reactor) with Toshiba designing and supplying the reactor of Unit 3. This is the MOX reactor and probably posses the greatest threat: http://en.wikipedia.org/wiki/MOX_fuel
- hellonearthis 3.2
  
  16 March 2011 at 2:09 pm
  
  The sea water is filtered
  http://www.sciencemediacentre.co.nz/2011/03/15/experts-on-japans-nuclear-crisis-and-analysis-of-the-earthquake/
  
  Q: What’ll happen to the water that’s being injected into the reactor when it’s thrown out? Will it pollute the environment? (Updated 18:00 March 14)
  
  A. Waste water with low levels of radiation will be passed through a filter before before disposed of. Waste water with high levels of radiation will be boiled. This will turn the radioactive material into solids which can be picked out before the water is disposed of. But the amount of water being injected in this case is significantly large so right now I don’t know what method they’ll ultimately choose to treat the water.
lprent 4

16 March 2011 at 11:40 am

I haven’t been able to find out what happens to the sea water after it has been used to cool the reactor – presumably it can’t be released back into the sea.

From what I understand it slowly vaporizes and is released as steam with a low radioactivity after various passive scrubbing.

It could be condensed and released at water. There isn’t the power to run the required pumps.

…Reactor 4′s containment building, exposing the storage pond to the air. Steam was seen rising from this pond, apparently from the spent fuel rod’s heat, then there was an explosion (cause unknown) and a fire. A fire is the last thing you want around fuel rods because it can break them up and carry the debris into the atmosphere, dispersing the radioactivity.

That is where the heavy element release appears to have been coming from. Sounds like they were doing triage and attacking the biggest issues first. Because of the lack of working sensors at least one got away from them. I’m more worried about that than the reactor 4. It doesn’t have nearly the same level of containment.

As someone said above, the situation is a SNAFU.

From what I understand… The reactors survived the quake which was well outside the build spec and shut down correctly. But the size of the tsunami was also larger than expected. It topped the seawall an hour later and effectively destroyed the generators that were required to run the cooling system and to cause hydrogen ‘reburning’ back to water in the reactor. It also destroyed large chunks of the external systems. Everything has been slowly going wrong since then with the engineers keeping a lid on the worst of it.

It is kind of weird. I suspect they may have been better off if the reactors hadn’t been turned off because the biggest issue appears to have been the unexpected loss of power. But I have no idea how much damage the tsunami did to the generation systems.
- Lanthanide 4.1
  
  16 March 2011 at 11:46 am
  
  Ok, so they were built to survive an earthquake, which they did. Apparently the safety systems kicked in within seconds of the quake striking (so the really big shaking wouldn’t have started) and the control rods were inserted automatically and everything was fine.
  
  The problem was the tsunami that came along, and apparently washed out the reactors. This plant is on the coast, how come they designed it to withstand quakes but not tsunamis? Doesn’t make a lot of sense. Shouldn’t they have had their generators in a secure underground bunker, with multiple underground power cables going to all necessary buildings, so that when a tsunami washed over the surface, once the water was clear there would’ve been no real damage to the generators?
  - Colonial Viper 4.1.1
    
    16 March 2011 at 12:17 pm
    
    AFAIK the GE mark I plants have a huge amount of their electrical switchgear in basements under the reactors.
    
    These basements got swamped with salt water and debris from the tsunami. That’s why getting the original/additional generators on line was originally such a slow affair.
    
    I am dead certain that at the moment (to steal a phrase from Montgomery Scott) the reactor’s control and electrical systems are “bypassed like a Christmas tree”.
    - Lanthanide 4.1.1.1
      
      16 March 2011 at 12:29 pm
      
      Evidently these basements weren’t adequately sealed off to prevent damage from the tsunami, which they should have expected. Certainly there was knowledge it was coming at least 30 minutes before it hit.
  - Richard 4.1.2
    
    16 March 2011 at 1:42 pm
    
    There seems to have been a seawall to prevent flooding from a tsunami — so it was thought of. It just wasn’t big enough.
    
    Putting stuff in “sealed” underground bunkers probably isn’t the right strategy for a tsunami — no matter how well you design it, it inevitably won’t be sealed properly, and it will flood.
    
    A seawall does seem to be the right strategy. It just needed to be bigger.
Tel 5

16 March 2011 at 12:11 pm

This might be slightly off topic, but related to the situation. There is a video link on the front page of the Herald on line of Dr Edwin Lyman from the Union of Concerned Scientists (whoever named this organisation must have had a chuckle?!) and about a minute in he says “Reactors are built to certain seismic standards. It’s very expensive, especially to retrofit a reactor for increased seismic standards. It seems pretty clear that this was an event that should have been anticipated and the outcome indicates that it was not fully, the impact was not fully understood on these reactors and therefore I would say it was a failure of Japan to treat its nuclear program with the level of care that it deserved.”

This got me thinking, why would anyone retrofit a reactor to an increased seismic standard? Ok it’s a given that design and development has moved on in the years since Fukushima was built, but as a designer, I cannot think of a bigger hospital pass (other than being a Fireman at Fukushima Firestation awaiting the alarm call to duty), than being asked to bolster up old technology, and sod the expense, especially when so much is at stake. Surely the only option is mothball the plant and build a new one? It’s a cruel outcome at Fukushima, and I wonder how many shareholders that have willingly banked years of profit takings are sleeping a little less easy, because they probably deserve to be.
- Colonial Viper 5.1
  
  16 March 2011 at 12:21 pm
  
  The Fukushima reactors were retrofitted with additional emergency pressure blow off valves to the reactors but only after the Japanese saw that the US operators had done that with all similar plants. That happened in the 1990’s.
  
  It is quite likely that enabled the engineers on site to keep some measure of control over the situation over the last couple of days.
- Lanthanide 5.2
  
  16 March 2011 at 12:38 pm
  
  I have heard, and the expert they interviewed on Nine to Noon also mentioned it but wasn’t sure of veracity, that just last month a decision was made to extend the life of these reactors by another 10 years, rather than go ahead with decommissioning them this year.
  
  On the plus side, this should mean that Japan wasn’t relying on these specific reactors for their electricity grid to keep functioning.
  - Colonial Viper 5.2.1
    
    16 March 2011 at 2:06 pm
    
    Yes I read in the hinudstan times that the original decommision date was Feb 2011.
marty mars 6

16 March 2011 at 12:12 pm

Aljazeera Net is pretty good with updates

http://blogs.aljazeera.net/live/asia/japans-nuclear-emergency-live-blog#

All we can do is watch and wait for the authorities to tell us what they want us to know. The truth will out, eventually – that is its nature. Without the net we would know next to nothing.

Thanks to The Standard for the posts on this – perhaps a standard news service could work.
Treetop 7

16 March 2011 at 1:13 pm

There is currently an intense fire in reactor 4 which was under control. Does anyone know if plutonium is in reactor 4? I do not think that plutonium was in the core of Chernobyl or 3 Mile Island, just uranium.
- Lanthanide 7.1
  
  16 March 2011 at 1:29 pm
  
  Googled this:
  
  “The rods, made by blending small amounts of plutonium with traditional uranium, were loaded into unit 3 of the Fukushima Daiichi nuclear plant last September.
  
  Makhijani said the unit contains 32 MOX assemblies—or about 5 percent of the fuel now in the reactor, where an explosion this week kindled fears of a radiation release. ”
  
  So a small number of the rods in #3 have a small amount of plutonium in them. So far the concerns about increased radiation output are around reactors #2 and #4.
  
  Plutonium is a concern because only a few grams are deadly to humans. But that is only a problem if the fuel rods themselves actually exploded or were released into the environment (as per Chernobyl), which still remains an unlikely event. So far the only radiation that has been released from these reactors has been iodine and caesium particles coming out in steam (and possibly the #4 fire), in other words the products from a nuclear reaction, but not the actual ingredients themselves – uranium and/or plutonium.
  - Treetop 7.1.1
    
    16 March 2011 at 1:41 pm
    
    Plutonium is a lot more expensive than uranium as well plutonium is required for a nuclear bomb.
    - Colonial Viper 7.1.1.1
      
      16 March 2011 at 2:08 pm
      
      Plutonium is more expensive, but its also a byproduct of some existing nuclear power reactions, so Japan probably considers it cheap fuel as they are supplying themselves with it.
      
      Essentially extending the useful life of their original uranium fuel by using the resulting plutonium by products.
- toad 7.2
  
  16 March 2011 at 1:49 pm
  
  The only one they have confirmed uses plutonium is reactor 3. That doesn’t necessarily mean it is the only one though – there was little attention on reactor 4 over the first few days as it had been shut down for maintenance. Fortunately, there are no reports of detection of plutonium around the plant.
  - Richard 7.2.1
    
    16 March 2011 at 2:03 pm
    
    Would they have individual reactors of similar vintage using fuels with different compositions?
    
    It would seem to be an unnecessary hassle — as you couldn’t as easy share fuel or fuel/waste handling systems.
    - Lanthanide 7.2.1.1
      
      16 March 2011 at 3:02 pm
      
      I posted in #7.1 above that the MOX fuel apparently makes up only 5% of the fuel used in reactor #3, and went into service only last September. It’s possible that they planned to use plutonium in the rest of the reactors as they refuelled them in the future, but hadn’t gotten to it yet.
      - Richard 7.2.1.1.1
        
        16 March 2011 at 3:44 pm
        
        Ah, I see, so they seem to be part way through a switch-over to a new fuel.
        
        Which may also explain why some reactors were shutdown (before the quake) and why the fuel for one (reactor four?) seems to be elsewhere (in the spent fuel pool instead of the reactor core).
        
        So, it is unclear then (from the media reports, anyway) precsiely which reactors are using a plutonium based fuel — other than the fact that reactor 3 definitely has some. There could also be some plutonium based fuel in storage systems (awaiting a switch-over).
  - Rich 7.2.2
    
    16 March 2011 at 9:29 pm
    
    All (uranium) reactors produce plutonium as one of the fission products. The first nuclear reactors (Hanford, Windscale) were designed purely to produce Pu for weapons. Modern power reactors produce less, but still make some. The reprocessing process extracts Pu for reuse/storage/bombs.
    
    (Well, not bombs from civil fuel, at least not in countries that comply with the non-proliferation treaty).
ianmac 8

16 March 2011 at 1:19 pm

The fire in No 4 appears to burnt itself out. Nat Radio at 1pm.
As Lanth points out the reactors were built to and survived the earthquake. The tsunami knocked out the electrical cooling system hence the problems. I guess that Fukishima is not the only reactor which is in reach of a tsunami. USA?
- Treetop 8.1
  
  16 March 2011 at 1:45 pm
  
  I was aware that the fire in no 4 was thought to have burnt itself out. Up date on the new fire at no 4. reactor http://www.stuff.co.nz/world/asia/japan-earthquake/4772530/Japan-earthquake-and-tsunami-Another-fire-erupts-at-nuclear-plant
  - Treetop 8.1.1
    
    16 March 2011 at 1:53 pm
    
    8.1 was referring to 12:49 pm update. The above link is to the 1:34 pm update, fire is now under control.
    - Colonial Viper 8.1.1.1
      
      16 March 2011 at 2:06 pm
      
      Problem is that these aren’t normal fires in that they are not likely to “burn themselves out” through running our of fuel any time soon e.g. like a house fire. The tonnes of metallic radioactive spent fuel will continue to burn for weeks or months if it is not covered with water. Any time the water cover is lost, there is a chance the fire will reignite.
      - Lanthanide 8.1.1.1.1
        
        16 March 2011 at 3:00 pm
        
        Yeah, I’m not clear on what is actually burning, though. You need 3 things for fire – heat, oxygen and fuel. The nuclear decay provides heat in abundance, and when the water gets super-heated to decompose to oxygen (probably need a pressurised environment for that) or the water level drops to expose the rods to the air, there’s obviously oxygen available.
        
        So what is the actual fuel that’s burning? Is it the uranium/zircalloy metal itself? The concrete? The other metals that make up the fuel?
        
        captcha: elements
        
        Richard 8.1.1.1.1.1
        
        16 March 2011 at 3:54 pm
        
        So what is the actual fuel that’s burning? Is it the uranium/zircalloy metal itself? The concrete? The other metals that make up the fuel?
        
        I think any and possibly all of these.
        
        If the heat generated by the nuclear decay is great enough, then the fuel will burn.
    - Lanthanide 8.1.1.2
      
      16 March 2011 at 2:58 pm
      
      I think when we comment on potentially confusing things, like fire or explosions, we should try and be very clear and timestamp all of it. Like instead of “fire at #4 reactor”, say “new fire that started at #4 reactor 10am today” or whatever, so everyone is clear what specific event we’re talking about.
    - Treetop 8.1.1.3
      
      16 March 2011 at 5:49 pm
      
      Another word about the link in 8.1 it keeps changing so just ignore my initial comment in 8.1
      
      The situation with reactor 3 in particular is becoming grave as the cause is unknown. Not to say that another reactor may do the unexpected e.g. catch alight or a hydrogen explosion.
hellonearthis 9

16 March 2011 at 1:59 pm

Those reactors where supposed to be decommissioned last month, but it had been delayed.
Jeremy H 10

16 March 2011 at 2:17 pm

The Earthquake was 7 times stronger than what the reactors were designed to handle, the tsunami wiped out the back up generators and the cooling systems ran off the batteries for 8 hours, the replacement generators that were trucked in had the wrong plugs and that is when things went pear shaped – when the batteries ran out… The level of water within the core dropped (as steam was vented to reduce pressure), raising the heat and exposing the 1st fuel rod containments which generated hydrogen which when vented caused the explosion between the 3rd and 4th containments in a number of the reactors, the 3rd containment is designed to contain a full meltdown at 3000 c and is made of 3 – 6 feet thick concrete and graphite… As long as these 3rd containments are sound there is no chance of a Chernobyl type incident, the fire in the spent fuel rod pond is troubling and has the power to release large amounts of radiation, as is the reports of the 3rd containment wall being breached in any of the reactors… Seawater will be run through the normal process for removing radioactivity…
- Treetop 10.1
  
  16 March 2011 at 2:42 pm
  
  On BBC radio I heard that the back up generators were not placed up in a high position and that the nuclear plant relied on the sea wall when it came to flooding.
  - ianmac 10.1.1
    
    16 March 2011 at 3:10 pm
    
    Yes Treetop. The stations survived the earthquake and shut down as designed. The problems arose when the tsunami swamped the systems.
  - Colonial Viper 10.1.2
    
    16 March 2011 at 3:24 pm
    
    Major electrical systems for these GE Mk I plants are located in (now flooded) basement levels. That will have been a factor in the pump systems failures we have seen.
Bright Red 11

16 March 2011 at 3:21 pm

A new fire or at least steam in Reactor 3, workers evacuated but no word on new radiation release.
- Jeremy H 11.1
  
  16 March 2011 at 3:50 pm
  
  They’ll be venting steam for a least a couple of weeks and with it goes hydrogen which reacts when it hits the air…
- toad 11.2
  
  16 March 2011 at 5:40 pm
  
  That’s the scariest one because that’s the reactor with the plutonium in its fuel rods – far more toxic than the radioactive decay products like iodine-131 and caesium-137 from uranium-235 fission.
  - Lanthanide 11.2.1
    
    16 March 2011 at 6:17 pm
    
    It’s only a problem if the rods themselves explode and get distributed into the atmosphere.
    
    That is a terrible outcome whether it is uranium or plutonium. Yes, plutonium is worse, but the “scariest” outcome is really the fuel exploding at any of the reactors, not just #3.
    - Colonial Viper 11.2.1.1
      
      16 March 2011 at 6:41 pm
      
      Melted, burning nuclear fuel is more than bad enough. Seriously hoping that there is no possibility of a criticality incident.
      - Rich 11.2.1.1.1
        
        16 March 2011 at 9:38 pm
        
        I was wondering about that, given that if enough fissile material pooled under a reactor it could reach a critical mass (as happened at Chernobyl).
        
        [This wouldn’t be on the scale of a nuclear explosion – wrong sort of fission. But it could produce energies in the range of tonnes of TNT equivalent).
        
        Lanthanide 11.2.1.1.1.1
        
        17 March 2011 at 12:49 am
        
        Yes, and this is a significant issue with the spent fuel rods at reactor #4. If the water level drops for too long (it may have already dropped below the level of the rods for some period of time) then rods may begin to melt.
        
        The resulting slag that sits on the bottom of the pool could reach criticality and as these rods aren’t in any real containment to the outside world, an unchecked reaction could result in a steam/hydrogen explosion distributing the radioactive isotopes into the atmosphere/environment.
    - toad 11.2.1.2
      
      16 March 2011 at 6:48 pm
      
      It seems the authorities have given up.
      
      http://www.youtube.com/watch?v=obHOBHDNlbs&feature=player_embedded
      
      Whatever will happen will happen.
dw 12

16 March 2011 at 10:30 pm

What most commentators miss is the Caesium 137 already releasedi s a by-product of the Fission process. This means that for Caesium 137 to be released into the environment, at least one or more fuel rods have broken casings. This also means there is considerable potential for additional release of heavier elements like Uranium and Plutonium, with much more severe health and safety consequences. Not that Caesium should be understated – it has a ‘short’ half life of around 30 years!
Also, I seem to remember a few years back the Japanese were caught falsifying safety certificates for their fuel rods, many of which had cracks in them before being loaded into plant cores. Again, a very worrying issue, but par for the course with the nuclear industry, which is seemingly incapable of operating responsibly. I guess you don’t have to when you get such generous state subsidies from tax payers (in the US, over 1 trillion dollars to date!).
- Lanthanide 12.1
  
  16 March 2011 at 11:48 pm
  
  1. Most people following this issue closely know about the caesium that has been released.
  
  2. The presence of caesium doesn’t mean there is “considerable potential for additional release of heavier elements like uranium and plutonium”, because caesium is water-soluble and was released with the steam that was to prevent the pressure from building up too high. Uranium and plutonium would only be released if the inner containment was broken (possibly the case in reactor #2, but unknown just how ‘broken’, it may only be a very small leak in a lower part of the building, ie not directly exposed to the air) and then there was a large explosion that resulted in direct damage to the fuel rods.
  
  This could happen if they melted and formed a critical mass on the reactor floor, creating enough heat to quickly rupture the pressure vessel. However at the moment such a scenario is considered “unlikely”, and will continue to be the case as long as they are able to pump seawater and boric acid into the reactors to cool them. Now if radiation levels at the site became so high that they were forced to evacuate and had to cease pumping the water, then that would be a possible outcome. At the same time however, it is likely that some people would risk their lives to continue to pump the water, because the death toll and consequences of a reactor explosion that unleashed uranium/plutonium to the atmosphere would be catastrophic.
  
  In short: without further unexpected developments, it is unlikely that uranium/plutonium will enter the atmosphere.
  - Marty G 12.1.1
    
    17 March 2011 at 12:05 am
    
    the rods regaining criticality and burning through the containment has to be the big worry.
    
    If I remember rightly though, sea water is an excellent neutron absorber, and I guess the boron they’re dropping in is too.
RedLogix 13

16 March 2011 at 10:39 pm

Of all that I’ve read in the last few days this comment on Climate Progress does seems to make a remarkable point:

There have been roughly 450 commercial nuclear reactors in the world. There were four destroyed at Chernobyl, one in Slovakia, one in Pennsylvania, and now at least three in Fukushima, for a total of nine destroyed. Of the nuclear plants over half are less than 30 years old, and the expected life for most of these plants (after the operating licenses are extended) is between 50 to 60 years.

The failure rate is thus 2% per 30 years, or almost 4% per operating lifetime. So a nuke has about one chance of 25 that it will destroyed before decommissioning.

This seems like a high failure rate.

I wonder if it it isn’t time to decommission this failed dream?
- Lanthanide 13.1
  
  16 March 2011 at 11:50 pm
  
  It certainly seems to me that these old reactor designs have severe short comings. See my post at #3.1.3 for a blatant example. I really do scratch my head wondering how people could be so stupid so as to store spent fuel rods essentially without any containment at all.
  
  Anyway the climate progress people are wrong about Chernobyl, from Wikipedia:
  “Despite the accident, Ukraine continued to operate the remaining reactors at Chernobyl for many years. The last reactor at the site was closed down in 2000, 14 years after the accident.”
  
  So only 1 reactor was destroyed, the other 3 continued to operate normally (wonder what sort of hazard pay the workers got!).
dw 14

16 March 2011 at 10:59 pm

Failed indeed. The most telling aspect of nuclear power is that nowhere in the world will a commercial entity build one – all plants have government subsidies and/or are built by government owned companies (e.g. see Areva in France), because they are simply not economic enough to generate a viable commercial return. The industry slogan should be “Nuclear Energy – the most expensive way to boil water”.
- Lanthanide 14.1
  
  16 March 2011 at 11:56 pm
  
  “because they are simply not economic enough to generate a viable commercial return.”
  
  Not because the technology doesn’t work, but because of the enormous bureaucratic paperwork burden in terms of consents and environmental impact statements etc.
  
  Furthermore there is economies of scale at work also. We build tens of thousands of wind turbines a year, and probably thousands of coal plants and tens to hundreds of dams, but maybe only a dozen nukes per year. Because of the regulations, the nuke plants that are built tend to be very big, complex and expensive to put out large amounts of energy, because it isn’t cost effective to make smaller ones. If the paper load were lightened, and safer, smaller reactors were built en-masse, the cost of nuclear power would be significantly less.
  - Morrissey 14.1.1
    
    17 March 2011 at 12:38 am
    
    Lanthanide, is your computer being used as a zombie by some loon from ACT or National? Because you have just written “If the paper load were lightened…”
    
    You—if it is you and not some fool in John Boscawen’s office—seem to be expressing some impatience with the idea of regulation and planning constraints for nuclear power plants. Are you seriously that contemptuous of democracy and openness?
    - Lanthanide 14.1.1.1
      
      17 March 2011 at 12:51 am
      
      I’m *not* saying that paper load *should* be lightened.
      
      I simply said if it *were* lightened, these plants could be built cheaper and faster. That seems like a rather obvious and indisputable claim.
  - wtl 14.1.2
    
    17 March 2011 at 1:09 am
    
    Not because the technology doesn’t work, but because of the enormous bureaucratic paperwork burden in terms of consents and environmental impact statements etc.”
    
    These are needed because the technology is inherently more dangerous that many other ways of generating electricity. There is no getting around this fact – the fuel is unstable and is highly toxic even in minute amounts. Therefore, even if it ‘works’ the technology should only be used if the necessary precautions are taken to ensure the risks are minimised, which requires careful consideration and, of course, paperwork.
    
    Even if commercial plants were to exist, the liability for the risks they pose would have to be underwritten by the government – I’m pretty sure no insurance company would ever cover them.
    
    Edit: Just saw you reply above. I see you weren’t implying that the paperwork should be lightened, but my second point still applies.
  - dw 14.1.3
    
    17 March 2011 at 1:53 pm
    
    “Not because the technology doesn’t work, but because of the enormous bureaucratic paperwork burden in terms of consents and environmental impact statements etc.”
    
    Sure there’s a regulatory burden, but it’s well known and necessary, even though the Nuclear industry routinely ignore or falsify their regulatory compliance to save money.
    
    The real problem is that this technology is inherently very complex and costly. The capital cost alone of building Nuclear plants has more than doubled in the past decade, because they use a lot of steel and concrete, and labour, not to mention the usual cost and time overruns. If you want a realistic view of nuclear power, please check out this link:
    
    http://www.thenation.com/article/what-nuclear-renaissance
Rosy 15

17 March 2011 at 12:19 am

France is the first country to urge it’s citizens to leave Japan. They don’t think this crisis is going to resolve anytime soon:
“The industry minister, Eric Besson, told BFM television:

Let's not beat about the bush. They have visibly lost the essential of control (of the situation). That is our analysis, in any case, it's not what they are saying.

The environment minister, Nathalie Kosciusko-Morizet, said the latest news about the nuclear situation "does not lead to optimism":

We recommend that all French citizens who do not have a good reason to stay in Tokyo either take a plane or, if they absolutely insist on staying, head south.

While this is not an official evacuation order, Air France has already increased capacity on its Tokyo to Paris services “