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While the media is spinning up on what is happening at Fukishima, I figured
I would put together a 101 discussion including my "RANK SPECULATION" on what happened, and what's gone wrong.  

Now the people with the best visibility into the accident I think were the shift operators,
and perhaps GE support staff or Japanese government regulators, but, the whole thing
is so complex a little education might help.

I found a NRC guide to teachers which is  a little simplistic but has some decent diagrams
and i have an earlier diary  
which has some really good diagrams.

so read the two links above and then lets discuss it

Inside the boiling water reactor (BWR) vessel, a steam water mixture is produced when very pure water (reactor coolant) moves upward through the core absorbing heat. The major difference in the operation of a BWR from other nuclear systems is the steam void formation in the core. The steam-water mixture leaves the top of the core and enters the two stages of moisture separation, where water droplets are removed before the steam is allowed to enter the steam line. The steam line, in turn, directs the steam to the main turbine causing it to turn the turbine and the attached electrical generator. The unused steam is exhausted to the condenser where it is condensed into water. The resulting water is pumped out of the condenser with a series of pumps and back to the reactor vessel. The recirculation pumps and jet pumps allow the operator to vary coolant flow through the core and change reactor power.

So that's where they were prior to the Quake...

Lots of backups, lots of redundancy, everything is great.

Then Wham  Quake.  

Now I don't know if the SCRAMed (Emergency Shutdown) before the quake

n any reactor, a SCRAM is achieved by a large insertion of negative reactivity. In light water reactors, this is achieved by inserting neutron-absorbing control rods into the core,

 due to the
Japan Emergency Quake Warning Network  

According to Masumi Yamada, an assistant professor in the Earthquake Hazards Division at Kyoto University, the 11 March earthquake began at 2:46 p.m. about 150 kilometers off the coast of Miyagi prefecture, and 31 seconds later, residents of the Tohoku region received the first warning via cellphone, TV, and radio. That gave people a lead time of between 10 to 30 seconds before they felt the first tremors [see map].

judging by the graph in the article the operators had some warning, but it's not reported wether they instituted a SCRAM prior to the quake or after.

Then the Tsunami came (I don't need any pictures, you've all seen that).
[Editors Note: I went ahead and added the post tsunami picture, because
it makes sense now that this diary is in the mothership}

You can see the damage to the inlet area, there is some damage out beyond the reactor buildings, but the rest of the reactor is in good shape.

 The Fukushima Dai-Ichi plant was only designed to withstand a 5.7-meter tsunami, not the 7-meter wall of water generated by last week’s earthquake or the 6.4-meter tsunami that struck neighboring Miyagi prefecture after the Valdiva earthquake in 1960, Ito said.

So the Tsunami was beyond desgn specs.
But apparently the quake was within design spec.
I can't find a reference but apparently the ground movement at Fukushima was
6.8 and the reactor was designed for 8.2  

but why did so much damage occur?

In 2004, an eruption of super-heated steam from a burst pipe at a reactor run by Kansai Electric killed five workers and scalded six others. A government investigation showed the burst pipe section had been omitted from safety checklists and had not been inspected for the 28 years the plant had been in operation.

were the plant internals properly inspected?

because apparently this was what it was like inside the plant

Soon the lights inside the building went out and emergency lighting came on. An announcement came next, telling workers to stay where they were. But seams on metal pipes installed in the ceiling had been broken by the strong jolts and water started flooding out.

Someone yelled: "This could be dangerous water. Let's get out of here!" and they rushed down the stairs to the first floor exit.

Workers are supposed to first report, without touching, water leaks they find inside the building. But continuing aftershocks made them more terrified of being trapped inside the building with the reactor than of the possibly radioactive water, he said.

When they reached the first floor, it was crowded with other employees changing out of their work uniforms and being tested for radioactive exposure before they left the building, as called for by regulations. But with only one testing device available, there was a long line of workers waiting in the narrow passage.

The aftershocks kept on coming and some people shouted angrily, "Hurry up!" He eventually found out he had not been exposed to radiation.

Now this wasn't hot water or they would have died, and it wasn't radioactive, but,
it raises questions about wether the critical piping failed.
Also, shouldn't an earthquake cause a plant emergency and all hands report to
damage control, station emergency stations,,,,

Much of the damage since Friday didn't come directly from the earthquake but rather from the accompanying tsunami, which swept away entire villages along the northeastern coast of Honshu, Japan's main island. The tsunami also flooded backup diesel generators at the Fukushima Dai-1 nuclear plant, thereby preventing cool-down measures. Japan has a tsunami early-warning system, but in this case, there was only about 15 minutes between the first tremors and the tsunami's arrival.

but they lost Grid Power, Station Power and were on Batteries and

apparently the diesels started and ran for an hour, then died.

The failure of the Fukushima plants’ diesel generators, which ran for only a short time after starting up when the main power supply failed, leading to a crippling loss of cooling capacity, raised particular concern.

Now as we said above the Reactors were Scrammed but you still have to cool
to remove Decay Heat.

On a SCRAM for a reactor that held a constant power for a long period of time (greater than 100 hrs), about 7% of the steady-state power will initially remain after shutdown due to the decay of these fission products. For a reactor that has not had a constant power history, the exact percentage will be determined by the concentrations and half-lives of the individual fission products in the core at the time of the SCRAM. The power produced decay heat slowly falls with the decay of fission products.

That's 5-7% of the Thermal Wattage.  The Fukushima 1 was 468MW, so as
thermal watts, thats 1.5 GW,  i can't tell if the decay heat is 7% of the electric
power or Thermal power, but between 35-105 MW of decay heat.  That's a lot of heat.

if you look at this drawing, you need a couple of pumps and that means power.
you need the turbine condensate pump, the recirc pump, the service water pump
and the residual heat removal pump.    Hard to provide if the generators are down.

Word from was the external fuel tanks out in the station switch yard were washed  away from  their mounts.

Apparently the diesels and an hours supply of diesels are in the basement,
now this drawing from Richard Cranium is a little small but it looks like the diesels,
a small fuel supply and switch gear are in the basement.  

It also looks like that is down below grade.  

which if they had water floating around the site, would have a chance to
leak into that gear down there.

so they switch to the Reactor Cooling system

So they are Back on Battery for some  reason and they announce they are
using a mechanical cooling system.

Now take a look at this  It's supposed to be Foolproof and Bulletproof.
Which means Nature is way smarter then we think.

that RCIC pump is mechanical and the recirc pump should run on a battery
or you can even live without it for a while.

slam a couple valves and bang, mechanical steam pump/ejector. which is supposed to bring in fresh water.  Yeah, you get some pumping into the torus, but, that's got
3 days, plenty of time to fix things and get back to normal.

Failure of mechanical cooling system

Cabinet Secretary Yukio Edano, the top government spokesman, said the nuclear power plant developed a mechanical failure in the system needed to cool the reactor after it was shut down.

Now they are on Battery,  but, they had switched to a mechanical Cooling system.

The reactor core isolation cooling (RCIC) system provides makeup water to the reactor vessel for core cooling when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. The RCIC system consists of a turbine-driven pump, piping, and valves necessary to deliver water to the reactor vessel at operating conditions. The turbine is driven by steam supplied by the main steam lines. The turbine exhaust is routed to the suppression pool. The turbine-driven pump supplies makeup water from the condensate storage tank, with an alternate supply from the suppression pool, to the reactor vessel via the feedwater piping. Thesystem flow rate is approximately equal to the steaming rate 15 minutes after shutdown with design
maximum decay heat. Initiation of the system is accomplished automatically on low water level in the reactor vessel or manually by the operator.

This was the one that puzzled me.

Why would a steam driven mechanical backup fail? How could it fail?

it sure looks to me like the water inlets are hosed.

The tsunami comes in trashes the inlets, so,  Heres the situation.  There is water all over
the place,  the Diesels are running, then they starve and die,  they switch to battery
and activate the Mechanical RICC, it's spinning, but, it's pulling poorly, and the operators
are so busy trying to fix the generators,  and deal with water leaking into the basement
they don't notice the reactor isn't cooling.(BTW i hear the tsunami actually
hydraulically shocked the service water system and the RCIC pumps.)

steam starts building up in the reactor and they have to start venting.

The operators have to be confused and in serious overload.
There are Diesel generators down, there must be water on the plant grounds, with
tons of debris all over the place.  There are probably leaks into the basement
which are knocking out systems.  They've switched to the RICC Mechancial
cooling system and the reactor is still heating up.

so they activate the Liquid Coolant Injection System.

The standby liquid control system injects a neutron poison (boron) into the reactor vessel to shutdown the chain reaction, independent of the control rods, and maintains the reactor shutdown as the plant is cooled to maintenance temperatures.
The standby liquid control system consists of a heated storage tank, two positive displacement pumps, two explosive valves, and the piping necessary to inject the neutron absorbing solution into the reactor vessel. The standby liquid control system is manually initiated and provides the operator with a relatively slow method of achieving reactor shutdown conditions.

Now the SLCS/LCIS isn't a big system but it's what you do when you think a control
rod is stuck, or busted, or the fuel bundles have shifted or the G&*D^&N reactor
won't shut off.  When you trip it, you are down for a month,  because it plates everywhere.  It's a last ditch thing.

And still the reactor temp is rising.

because they don't realize the RCIC isn't working.

Now the temps are still rising,  and they are desperate to get the diesels working
again, because that will allow them to run this

The emergency core cooling systems (ECCS) provide core cooling under loss of coolant accident conditions to limit fuel cladding damage. The emergency core cooling systems consist of two high pressure and two low pressure systems. The high pressure systems are the high pressure coolant injection (HPCI) system and the automatic depressurization system (ADS). The low pressure systems are the low pressure coolant injection (LPCI) mode of the residual heat removal system and the core spray (CS) system.
The manner in which the emergency core cooling systems operate to protect the core is a function of the rate at which reactor coolant inventory is lost from the break in the nuclear system process barrier. The high pressure coolant injection system is designed to operate while the nuclear system is at high pressure. The core spray system and low pressure coolant injection mode of the residual heat removal system are designed for operation at low pressures. If the break in the nuclear system process barrier is of such a size that the loss of coolant exceeds the capability of the high pressure coolant injection system, reactor pressure decreases at a rate fast enough for the low pressure emergency core cooling systems to commence coolant injection into the reactor vessel in time to cool the core.

The High Pressure Emergency Core Cooling System

as you can see from this diagram, the ECCS can handle any large break and keep
water pouring in.

The high pressure coolant injection (HPCI) system is an independent emergency core cooling system requiring no auxiliary ac power, plant air systems, or external cooling water systems to perform its purpose of providing make up water to the reactor vessel for core cooling under small and intermediate size loss of coolant accidents. The high pressure coolant injection system can supply make up water to the reactor vessel from above rated reactor pressure to a reactor pressure below that at which the low pressure emergency core cooling systems can inject.
The automatic depressurization system (ADS) consists of redundant logics capable of opening selected safety relief valves, when required, to provide reactor depressurization for events involving small or intermediate size loss of coolant accidents if the high pressure coolant injection system is not available or cannot recover reactor vessel water level.

So what the heck happened here?  The HPCI, a independent system failed?
Apparently the condensate water tanks were damaged by the tsunami
and they were causing air bubbles to get sucked in so the HPCI was blowing air.
And Nobody in the plant was able to identify the leaks.

You know at this point the Operators must be just freaking out.

They've just had their heads rattled, the tsunamai is busting all sorts of things
and all the easy options have failed.

what makes this worse, is i bet the replacement shift isn't making it in to work.
So these operators have to be tired.

The automatic depressurization system (ADS) consists of redundant logics capable of opening selected safety relief valves, when required, to provide reactor depressurization for events involving small or intermediate size loss of coolant accidents if the high pressure coolant injection system is not available or cannot recover reactor vessel water level.

They have power shortages, the routing things haven't worked, and the usual failure control mechanisms aren't working. So they opt to Depress the Reactor.
After all, if it's not cooling, it's got to be boiling, and maybe they think the
pressure is more then the system can pump against.

So they start venting.  They vent from the Reactor vessel into the Primary containment
running that pressure up to 60 PSI.

    Despite the high risk of the hydrogen ignited after combining with oxygen in water or the atmosphere, in order to release some of the pressure inside the reactor at Fukushima I unit 1, the decision is taken to vent some of the steam (which contained a small amount of radioactive material) into the air in the concrete container building surrounding the unit.
The primary containment is designed to condense steam and to contain fission products released from a loss of coolant accident so that offsite radiation doses specified in 10 CFR 100 are not exceeded and to provide a heat sink and water source for certain safety- related equipment.
The Mark I containment design consists of several major components, many of which can be seen on page 3-16. These major components include:

•    The drywell, which surrounds the reactor vessel and recirculation loops,
 •    A suppression chamber, which stores a large body of water (suppression pool), •    An interconnecting vent network between the drywell and the suppression chamber, and •    The secondary containment, which surrounds the primary containment (drywell and suppression pool) and houses the spent fuel pool and emergency core cooling systems.

it's not a great decision, but, the concern is probably to let the radiatioactive gas
cool rather then send it up the vent stacks.  Probably the wind direction is poor
and the evacuation isn't running,  and

They are probably reaching the limits of the Primary Containment so they
must decide to start venting into the Secondary containment.

and BANG

    Unit 1 at Fukushima I: cameras document a massive hydrogen explosion on the outer structure of one of four buildings at the plant. It also documents the outer structure collapsing. TEPCO 3 hrs later announces that four persons who are employed at the power plant have been injured.

Now they are really Screwed..

Now it seemed odd for me that the Operators chose to vent into Secondary
Containment because it's not designed for pressure and pushing up the flare stack
would be a better option.  It has filters and would stop the particles letting up short lived gasses.

But All Things Nuclear raises a very interesting prospect here

A hissing sound attracted workers to the top of the containment structure. They identified air leaking through the drywell flange area (see Figure 1). The metal drywell head (see Figure 2) is bolted to the metal drywell with a rubber O-ring between the surfaces to provide a good seal fit.

Workers found that the containment pressure of 70 psi pushing upward against the inner dome of the drywell head lifted it off the drywell flange enough to provide a pathway for air to leak from the containment. That air leaked into the area labeled refueling cavity in Figure 1. The refueling cavity is located outside the primary containment but inside the reactor building.

At Brunswick, workers tightened the drywell head bolts beyond the amount specified in the reactor plans in order to reduce the leak rate and continue the test. While workers conducted pressure tests at all nuclear reactors prior to initial startup and periodically thereafter, these tests were performed at or below the containment design-pressure of 62 psi. So none of them reached the pressure that caused the leak around the drywell head.

In other words, had Brunswick not featured a prototype containment design, its initial and recurring pressure tests would have been conducted at 62 psi, not 71 psi. Leaking from the drywell head was not observed until the containment pressure rose to 70 psi.

How does this Brunswick containment testing experience relate to the reactor building explosions experienced at Fukushima Dai-Ichi Units 1 and 3?

Like Brunswick, the containment design at those reactors features a drywell head bolted onto the lower portion of the drywell. Workers at these reactors faced siginficant problems cooling the reactor cores. The combined effects of the earthquake and tsunami left the reactors without ac electrical power. The only dc-powered (i.e., battery-powered) backup system was lost when the batteries were exhausted. Workers turned to their only remaining option: injecting sea water into the reactor vessels to cool the reactor cores.

The pumps used to pump seawater into the vessel operated at low pressure. When seawater entered the reactor vessel, it was heated by the hot reactor core to the point of boiling. Steam produced by the boiling increased the pressure inside the reactor vessel. To prevent this rising pressure from hindering seawater from being pumped into reactor, workers periodically vented the reactor vessel. This carried steam and gas, including hydrogen, into the primary containment. This flow in turn increased the pressure inside containment. When containment pressure rose too high, workers vented the containment to the atmosphere.

The workers properly sought to minimize the amount of gas they vented from containment to the atmosphere to lessen the amount of radiation released. They did this by allowing the containment pressure to rise as high as tolerable between ventings.

It is possible that the containment pressures rose high enough to replicate the Brunswick experience by lifting the drywell head enough to allow hydrogen and other gases to leak into the refueling cavity and reactor building. If so, hydrogen could build up to an explosive mixture.

This tragedy will be closely examined for its causes. That scrutiny must determine how hydrogen got into the reactor building early in the crisis. The drywell head pathway may be that answer.

Answering this question is critical to prevent hydrogen explosions at the other reactors at Fukushima.

If this mechanism is the cause of the leak, it could be averted easily and effectively simply by changing the venting procedures so that workers vent the containment pressure to the atmosphere more frequently and do not let it build up to such high level. Taking such action might moderately increase the amount of radioactive gases vented into the atmosphere, but could eliminate a source of hydrogen inside the reactor buildings that could cause another explosion.

Authorities should launch an  investigation to pinpoint the source of the hydrogen leak to eliminate this risk in the future. But in the meantime, since the Brunswick test showed that this containment is vulnerable to high-pressure leaking, Tokyo Electric Power Co. can and should take immediate steps to avoid creating such a leak by changing its procedures to vent the containment before it builds up to such high pressure (70 psi).

There is an excellent diary on the problems in the Fuel Ponds, and
I heartily reccomend them, but the Fuel ponds in reactor 1 are
now exposed, there is severe damage to them, and, Reactor 1 is
still unstable.....

The point of this diary was merely to discuss how they got to that situation.
Where it ends, who knows.  I think a radioactive lizard is the best hope.

I will recommend you to them,  but I wanted to discuss why I thought the
Initial reactor cooling systems had failed.

1) Loss of station power led to loss of situation awareness and a focusing of
staff on the diesel emergency generator conditions and trying to get them back on

2) damage to the water inlets and piping demolished what were simple
mechanical systems in the RCIC and HPCI ECCS.

3) venting into the building rather then up the stacks led to 2 hydrogen explosions.

4) difficulties getting station power up and realizing the damage to the service water
system led to boiling and explosions in Rac 2 and rac 4 (Fuel Ponds).

5) I suspect replacement workers were unavailable leading to fatigued and
shellshocked operators losing efficiency over time

6) I have to add poor design, manufacturing, etc leading to failures of critical systems.

At this point in time, it's no longer a fight for the reactors, it's almost a fight for
the fuel ponds.

Originally posted to nathguy on Thu Mar 17, 2011 at 01:04 PM PDT.

Also republished by Japan Nuclear Incident Liveblogs.

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Comment Preferences

  •  Tip Jar (20+ / 0-)

    George Bush is Living proof of the axiom "Never send a boy to do a man's job" E -2.25 S -4.10

    by nathguy on Thu Mar 17, 2011 at 01:04:26 PM PDT

    •  WELL DONE! (0+ / 0-)

      Very, very good.

      I appreciate your hard work in producing this.

      For Republicans everywhere, you should remember this statement: "The values inspiring those brave workers in Poland … They remind us that where free unions and collective bargaining are forbidden, freedom is lost." (Ronald Reagan 1980)

      by Nebraskablue on Thu Mar 17, 2011 at 08:20:54 PM PDT

      [ Parent ]

  •  I heard the diesel generators were junk... (1+ / 0-)
    Recommended by:

    and that they never had the capacity to handle the stresses that would be imposed on them during an emergency.

    "Ich bin ein Dachs!"

    by PvtJarHead on Thu Mar 17, 2011 at 01:30:39 PM PDT

  •  Interesting... (2+ / 0-)
    Recommended by:
    California06, synductive99

    That was very informative. Thank you.

    I'll add my layman's assessment...

    It's also possible there was some structural damage caused by the earthquake and aftershocks. I recall watching a translated Japanese newscast in the first couple day where the gentleman explained how one of the pools was not holding water- possibly due to a leak. It's possible that some of the pipes leading into and out of the systems were damaged, either allowing water to drain out, or preventing it from coming in, by the Quake itself. There could even be some kind of crack running through the compound.

    My understanding is that these rods overheat very quickly without coolant. The partial meltdown that occurred at Three Mile Island only took a few hours to do irreparable damage. It's been days in this case.  

    Once temperatures reach a certain point,  the system may not be capable of providing enough water to cool things down- even if you do get it back online, and nothing is damaged. You'll need extra pumps and a larger source of water, which seems to have been the case.  I could probably find the formula for that, but my guess is, there is/was simply not the ability or machinery available to transfer that much water to not just one tank, but six overheating tanks.

    This heli-bucket brigade just seems utterly futile, and I am shocked & quite dissappointed this is the best man can do.

    Icarus, here we come!

    Thanks again for a great post.

    “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

    by Terranova0 on Thu Mar 17, 2011 at 02:00:41 PM PDT

    •  YAY! Finally some good news. (1+ / 0-)
      Recommended by:

      The longest extensions cord in the world has been plugged in!  This is great news for #5 and #6. And maybe they can get some working pumps in the others.

      “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

      by Terranova0 on Thu Mar 17, 2011 at 03:01:55 PM PDT

      [ Parent ]

      •  Whoo Hoo! Offsite power is a very good thing (1+ / 0-)
        Recommended by:

        I read earlier that they had one of the diesels working and were using that to maintain fuel pool and reactor water levels at 5 & 6 while focusing on hooking up 1-4 to the new power tether.  

        Free: The Authoritarians - all about those who follow strong leaders.

        by kbman on Thu Mar 17, 2011 at 03:45:33 PM PDT

        [ Parent ]

      •  So what next? (0+ / 0-)

        I'm not sure if grid power is enough to
        resolve the crisis.

        George Bush is Living proof of the axiom "Never send a boy to do a man's job" E -2.25 S -4.10

        by nathguy on Thu Mar 17, 2011 at 04:43:34 PM PDT

        [ Parent ]

        •  Next... (1+ / 0-)
          Recommended by:

          "resolve' might never apply to this situation.  =/

          Power will definitely help them manage this better. Improved monitoring, for one.  And they can plug in more pumps, as well as (hopefully) avert crisis in #5 & #6.

          If folks are truly serious about Nuke Power, we'd better invest more in robotics.  

          “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

          by Terranova0 on Thu Mar 17, 2011 at 05:46:01 PM PDT

          [ Parent ]

          •  'regulatory requirements' (0+ / 0-)
            Rapid depressurization of the reactor is
            desirable to permit flow from the low pressure emergency core cooling systems so that the temperature
            rise in the core is limited to less than regulatory requirements.

            This is why I suspect that once temperatures are too high, that the cooling system, even in perfect working order, cannot keep up with the evaporation of water--especially when primary systems are impaired.

            It may even prove true that the emergency systems were never capable of maintaining proper temperatures, especially over long periods, such as encountered.  I believe it's possible that when they said they had 8 hours of "battery time" that meant they had 8 hours to get ALL cooling systems back online.

            From that 9th hour forward it appears to have been a nearly futile battle, and with mounting radiation there are not many options, even with power.

            “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

            by Terranova0 on Fri Mar 18, 2011 at 09:08:09 AM PDT

            [ Parent ]

            •  nah (1+ / 0-)
              Recommended by:

              if the primary power and pumps are working, they
              can handle the evaporation requirements.

              Look here's the numbers.

              Take Reactor 3,  758 MW, it's effectively 2200 Thermal watts.
              It will have a 7% Decay heat when it's SCRAMMED.

              so that's 150 MW.

              now it's 259588 kJ to boil 100 KG of water so figure
              58800 KG of water or 60 Tons of water per second.

              so thats' 58000 liters per second or 15,000 Gallons/second

              It's a lot, but, you have to remember the primary pumps
              move a lot more water to keep it cool at full power.

              You need a lot smaller pump for shutdown.

              George Bush is Living proof of the axiom "Never send a boy to do a man's job" E -2.25 S -4.10

              by nathguy on Fri Mar 18, 2011 at 07:26:20 PM PDT

              [ Parent ]

              •  Thanks for doing the math (0+ / 0-)

                Of course, we hope they did the math, too. Clearly, they were not able to get enough water in there in time. Looking at the pictures of the initial damage, it's easier to understand why. Were you able to find them online?

                “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

                by Terranova0 on Sat Mar 19, 2011 at 06:06:23 AM PDT

                [ Parent ]

  •  Good Work! (0+ / 0-)

    What is the plan for when they get the power lines working?

  •  New Photos (0+ / 0-)

    Looks grim. Looks like whole systems are wiped out.


    “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

    by Terranova0 on Fri Mar 18, 2011 at 05:47:47 PM PDT

    •  can you add them to the comments? (0+ / 0-)


      George Bush is Living proof of the axiom "Never send a boy to do a man's job" E -2.25 S -4.10

      by nathguy on Fri Mar 18, 2011 at 06:43:01 PM PDT

      [ Parent ]

      •  I saw them on TV (0+ / 0-)

        They may be available online.

        “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

        by Terranova0 on Fri Mar 18, 2011 at 07:27:10 PM PDT

        [ Parent ]

      •  Interesting article... (0+ / 0-)

        Possible Cause of Reactor Building Explosions

        Kinda picks up where you leave off with the BOOM... I won't pretend I fully grasp all the techno babble, but it does help me to understand and conceptualize the how and why.  Thank you for entertaining my comments.

        Found this interesting from the article...

        But as workers increased the containment pressure they encountered a problem. The pressure stopped increasing and remained constant at 70 psi. The pumps continued to push air into the containment, but its pressure just stopped increasing. This unexpected plateau started a hunt for air leaking from the containment somewhere
        It is possible that the containment pressures rose high enough to replicate the Brunswick experience by lifting the drywell head enough to allow hydrogen and other gases to leak into the refueling cavity and reactor building. If so, hydrogen could build up to an explosive mixture.

        Sounds like a design flaw may have played a part, if I am understanding this correctly.

        “The most important trip you may take in life is meeting people halfway” ~ Henry Boye~

        by Terranova0 on Sat Mar 19, 2011 at 01:48:22 PM PDT

        [ Parent ]

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