Japan Nuke plants

Gordy

 Having worked in a nuclear power plant on the turbine deck, and containment area this is scary times, and sad. 



  The power of steam to drive the turbines is amazing, and damaging. I have witnessed during outages what steam has done to 16" dia. stainless steel pipes at elbows eroding the steel away like some one took a torch to it on the inside.  Erode turbine blades. This is all anticipated, and the reason for outages to perform inspection, and maintenance from such occurrences.



 The complexity of these nuclear plants is awe inspiring to say the least. The Byron facility close to me had to replace a steam vessel in the containment that was suppose to last 30 years in 15 years. In order to do this they had to build a containment attached to the containment to exchange the new vessel for the old. The old radioactive vessel being left in the new containment addition. First time something like that had been done.



   Japans power plant dilemma is going to be a set back to nuclear oriented power generation to say the least which I find to be saddening. Things happen. Engineers try to design for the worst case scenario. Sometimes things get missed or events are more devastating than could be imagined. I just hope things can be controlled to prevent a melt down, and Japan can be seen as a pillar in the nuclear generation community on how they handled catastrophic events successfully with as little impact to the environment, and human element possible.





 Gordy





 

Mark Eatherton

Worst case scenario.

The Japanese had some of the most advanced warning and controls systems possible. They knew they were building reactors in areas that were prone to quakes and Tsunamis. They had a back up plan to their back up plan, and unfortunately, they all failed.



If a quake was detected, the plant was to trip off line, and emergency generators were supposed to kick in and allow them to shut the reactor cored down correctly and safely. If the generators should fail, they had a battery back up to keep the pumps running to cool the reactor and buy some time for a plan C.



Plan C in this case is to dump/pump sea water into the reactor in an attempt to cool it down.



Scary stuff here. And I am certain that many lessons will be learned, and the results of those lessons shared with the nuclear world.



I am a firm believer that nuclear energy will eventually power the majority of the world.



ME

Steamhead

On YouTube

"RussiaToday" was comparing this situation to the Chernobyl disaster. Their latest one is here:



http://www.youtube.com/watch?v=7Vpg8eleaeM



But the GE reactor (yes, our very own GE) at Fukushima-1 at least has a containment building, just like the Babcock & Wilcox one did at Three Mile Island, whereas the RBMK-1000 did not.



The problem is that even after a reactor is shut down it still needs to be cooled. This is one thing that makes nuclear such an unforgiving technology. The smallest breakdown can pyramid into disaster. At TMI, a control system malfunction and operator error resulted in a loss of cooling which led to a partial meltdown.

Gordy

Cooling

   The byron facilty requires 50,000 gpm to cool its reactors. Thats a lot of pumping  to run on batteries for a long period of time.



   I do not know how long an emergency shut down takes.  Shut downs for planned outages take weeks to keep from damaging components outside the reactor itself. But these planned ouages take place near the end of the fuel rods life span. 



   Example being the turbine which rides on a high pressure film of oil during full operation. Ramping it down it goes to a turning gear after it slows to so many rpms then it turns on the turning gear slowly for days until it stops to prevent damage to the turbine shaft.



  The generator at the end of it all is about 500,000 pounds, and the size of a two car garage.  When you look at all the complexity in the end its all done just to turn this generator.  All so you can get up in the middle of the night to take a leak, and not be in the dark.  As one old timer I worked with put it.

LarryC

BWR or PWR ?

Gordy, is Byron a PWR or BWR plant?

My guess as to why it takes so long to shut down the steam plant is to minimize the amount of positive reactivity to prevent the fuel from going critical with the cooler water. This is done to minimize the amount of time required to perform the the core maintenance and fuel shuffle.  The refueling floor work is typically the critical path maintenance.

 

Also a slower cooldown minimizes thermal stresses on the steam side components.

Gordy

Pwr

2300 MW Pressurized light water reactor.  there are 2 reactors at Byron Larry

I suppose in an emergency scenario the infrastructure for the drive line components are sacrificial to prevent a catastrophic failure of the reactor. But I do not believe the reactor can be shut down in the time frame of the quake tsunami double wham happened. We really do not know what actually happened for sure was it the quake that caused the initial failure or the tsunami? Does anybody know the time span from initial quake to tsunami actually over taking the plant?



Basically Japan is going to have three monoliths, and counting.  I'm sure the world will question the remaining plants operation, and the design build of a new plant in that country.......Depending on the outcome of this tragedy, not looking favorable as things unfold.

Gordy

If interested

www.eia.doe.gov/cneaf/nuclear/state_profiles/illinois



This link is interesting. Illinois gets 50% of its electricity from Nuclear Energy.

Mark Eatherton

Not looking too good.....

I am by no means an expert in explosive forces, but when I see the amount of material that you can see in this video suspended in mid air, it would indicate to me that there is a lot of concrete being lifted into the air, as in concrete containment structure.



In the chemical manufacuring business, they intentionally build the buildings to allow them to blow apart in case of an explosion, and that is what appeared to happen in the first reactor explosion, but this one looked completely different. Substantial lift, then a lot of heavy debris falling back to Earth.



Now they are saying that the spent fuel rod facility for #4 was allowed to be exposed, and subsequently caught on fire, and that they suspect the radiation in suspension probably came from that fire. The fire is out for now, but they are struggling to keep the rods covered with water.



God bless the brave nuclear warriors who have stayed on site in an effort to get this situation under control. Scary stuff here...



This makes the oil spill of last summer pale by comparison...



http://www.youtube.com/watch?v=pIZKlaEZMLY



What could POSSIBLY go wrong next !?



ME

Jean-David Beyer

What could POSSIBLY go wrong next !?

When I first started as a student at a prestigeous engineering school, I was introduced to Murphy's laws. I later learned, in the scholarly journal, Mad Magazine, that Mr. Murphy's first name was Edsel.



In any case, the first tree laws were:



1.) If anything can go wrong, it will.

2.) If several things can go wrong, they will all go wrong, all at once.

3.) The amount you learn from this is proportional to the cost of equipment destroyed.



The next three went:



4.) You can't win.

5.) Wou can't break even.

6.) You can't get out of the game.

Mike Kusiak_2

Sequence of events

Here is the best description I have found of the Japanese nuclear accident, without all the media hype.



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



With everything that has gone wrong, its amazing that so far the result is not worse.

Mike Kusiak_2

Cutaway reactor drawing

Mark, you bring up a good point. The initial explosion seemed to only blow off the light metal construction at the top of the reactor building, while the last explosion seemed to involve some of the heavier concrete below hat level.

Jean-David Beyer

I am less worried about the containment...

... than I worry about the spent fuel rods in the storage pools. These are outside of the containment, but must nevertheless be cooled.  Presumably there is failure in this cooling because the hydrogen that has been exploding is probably due to the zirconium of the cladding around the fuel getting so hot as to grab the oxygen from the water, leaving free hydrogen to explode once it finds some air. Now that the roof has been blown off some of these reactors, if that stuff catches fire, it becomes a major calamity. And they did have a fire there in unit 4 that took them about 2 hours to put out.



And their using sea water to replace the coolant, even with boric acid in it, is very corrosive as those here who got a little in their boilers can attest. Probably worse in the reactor and storage pool if the circulation is too low and the temperatures exceed 2000F.

Gordy

Not over for months

   No one has said when these reactors were fueled.  Usually they will run 9 months freshly fueled with CONTROLLED reaction. Usually reactors are fueled in such an order that while one is down for maintenance, and refueling the others are operational. How they are staggered depends on how many reactors are on the site.  Most plants here in Illinois have 2 reactors. Some are PWR some are BWR. Japans site has 6 much more of a complex of a site to maintain.



 Looking at the size of the explosion in Marks youtube link I would say they had some Containment damage. 



 With that being said a freshly fueled reactor will take longer to keep under control which appears to be a struggle now. They need an end to come to this soon being operating in emergency mode, and the Hail Mary sea water boric acid pass to absorb neutrons, and slow the reaction.  These workers are going to get dosed in a hurry, and new ones will need to be rotated. Time, shielding, and radiation level all come in to play here.



    Gordy

Gordy

Dump GE

 If you own any stock. Their Mark 1 reactors have been known to be troubled. This will be litigation heaven.  I hope the workers are getting rotated according to the latest news.  I can't believe our satellites are not monitoring the radiation. Time for outside sources to step in if not to late. Japan has way to many things going on right now to handle this also.

Jean-David Beyer

Probably too late.

If you go here,



http://bigcharts.marketwatch.com/interchart/interchart.asp?symb=ge&insttype=&time=&freq=



And set Chart Range to 5 days, and Chart Frequency to 1 minute, you will see quite a dip; it dropped $2 this morning, about 10%.

Steamhead

Well, at least

they weren't Babcock & Wilcox!

BobC

GE mark 1 reactor problems

DEVASTATION IN JAPAN



Warning was issued in ’70s on GE-designed reactors

By Tom Zeller Jr. New York Times / March 16, 2011



NEW YORK — The warnings were stark and issued repeatedly as

far back as 1972: If the cooling systems ever failed at a

Mark 1 nuclear reactor, the primary containment vessel

surrounding the reactor would probably burst as the fuel

rods inside overheated. Dangerous radiation would spew into

the environment.



Now, with one Mark 1 containment vessel damaged at the

embattled Fukushima Daiichi nuclear plant and other vessels

there under severe strain, the weaknesses of the design —

developed in the 1960s by General Electric — could be

contributing to the unfolding catastrophe in Japan.



When the ability to cool a reactor is compromised, the

containment vessel is the last line of defense. Typically

made of steel and concrete, it is designed to prevent — for

a time — melting fuel rods from spewing radiation into the

environment if cooling efforts fail.



In some reactors, known as pressurized water reactors, the

system is sealed inside a thick steel-and-cement tomb. Most

nuclear reactors around the world are of this type.



But the type of containment vessel and pressure suppression

system used in the failing reactors at the Fukushima Daiichi

plant is physically less robust, and it has long been

thought to be more susceptible to failure in an emergency

than competing designs. In the United States, 23 reactors at

16 locations use the Mark 1 design, including Pilgrim 1 in

Plymouth, Mass.; Vermont Yankee in Vernon, Vt., and the

Oyster Creek plant in central New Jersey.



GE began making the Mark 1 boiling-water reactors in the

1960s, marketing them as cheaper and easier to build — in

part because they used a comparatively smaller and less

expensive containment structure.



US regulators began identifying weaknesses very early on.



In 1972, Stephen Hanauer, then a safety official with the

Atomic Energy Commission, recommended that the Mark 1 system

be discontinued because it presented unacceptable safety

risks. Among the concerns cited was the smaller containment

design, which was more susceptible to explosion and rupture

from a buildup in hydrogen — a situation that may have

unfolded at the Fukushima Daiichi plant.



Later that same year, Joseph Hendrie, who would later

become chairman of the Nuclear Regulatory Commission, a

successor agency to the atomic commission, said the idea of

a ban on such systems was attractive. But the technology had

been so widely accepted by the industry and regulatory

officials, he said, that “reversal of this hallowed policy,

particularly at this time, could well be the end of nuclear

power.’’



In an e-mail yesterday, David Lochbaum, director of the

Nuclear Safety Program at the Union for Concerned

Scientists, said those words seemed ironic now, given the

potential global ripples from the Japanese accident.



“Not banning them might be the end of nuclear

power,’’ said Lochbaum, a nuclear engineer who spent 17

years working in nuclear facilities, including three that

used the GE design.



Questions about the design escalated in the mid-1980s, when

Harold Denton, an official with the NRC, asserted that Mark

1 reactors had a 90 percent probability of bursting should

the fuel rods overheat and melt in an accident.



Industry officials disputed that assessment, saying the

chance of failure was only about 10 percent.



Michael Tetuan, a spokesman for GE’s water and power

division, staunchly defended the technology this week,

calling it “the industry’s workhorse with a proven track

record of safety and reliability for more than 40 years.’’



Tetuan said there are currently 32 Mark 1 boiling-water

reactors operating safely. “There has never been a breach of

a Mark 1 containment system,’’ he said.



Several utilities and plant operators also threatened to

sue GE in the late 1980s after the disclosure of internal

company documents dating to 1975 that suggested the

containment vessel designs were either insufficiently tested

or had flaws that could compromise safety.



The Mark 1 reactors in the United States have undergone

modifications since the initial concerns were raised. Among

these, according to Lochbaum, were changes to the

doughnut-shaped torus — a water-filled vessel encircling the

primary containment vessel that is used to reduce pressure

in the reactor.

Jean-David Beyer

Oyster Creek...

"In the United States, 23 reactors at



16 locations use the Mark 1 design, including Pilgrim 1 in



Plymouth, Mass.; Vermont Yankee in Vernon, Vt., and the



Oyster Creek plant in central New Jersey."



Oh! Poo! I live less than 40 miles from that one.

NH03865

You're Lucky

I live 70 miles from BOTH of the other 2

Steve_175

Looks like it's getting worse

http://www.nytimes.com/2011/03/17/world/asia/17nuclear.html?_r=1&hp

LarryC

20/20 Hindsight

My guess at a fundemental flaw at the Japan plants, is the same one that bit us in Katrina.  The emergency generators and switchgear are located on or below the ground.  Any significant flooding and you are at the bottom of the pool.  The shaking did not cause the failures, it was the lack of emergency power from the flooding that did them in. 

Unfortunately it is expensive to fix, and we are still stuck with millions of industrial, commercial, and residential locations worldwide with this same issue.

 

20/20 hindsight.

Gordy

Try to

 Plan for the worst, and hope for the best. Many design flaws in all facets of construction which are only revealed after catastrophic events of inconceivable proportions.



 Their use to be a show on T.V. called failure analysis I think. I enjoyed watching what can be learned from failures.  Some things are discovered through an event failure analysis like during construction a 1 1/2" re bar spacer was used instead of a 1" which was determined to cause a failure. No one could probably believe that 1/2" difference in re bar clearance could make so much of a structural difference.





 What designer would ever consider a direct hit from a passenger airliner at near Mach speed to a building let alone 2 minutes apart to separate buildings in close proximity to one another would really happen. But they did with the World Trade Center buildings. Never thought about the amount of damage the burning fuel would cause only the impact.





 The events in Japan are three catastrophes at once. Any one of them would be bad enough on its own. Let alone a quake, Tsunami, and A nuclear reactor failure do to the Tsunami.  At the time of the Nuclear Plants design 70's there was not the information known today about how quakes, and Tsunamis fault line locations etc.  are events tied to one another as we come to know today.  So I'm sure the designers banked on one event happening, and not another.  But the Tsunami event alone would have done the same damage to redundant cooling systems which is really the whole issue here, and that is the ability to move cooling water to the reactors, and fuel storage ponds.







  At any rate it will be a learning experience for the world.  I see the NG, and coal advertisements taking off right now on the TV.





  The CEO of Exelon Corporation which operates nuclear power plants even says that nuclear is cost prohibitive today. The best play is solar/ wind with NG/ Coal as the balance to the lack of wind, or night time demands.



  The problem with that is the technology to capture solar is very inefficient. do we cover the planet with todays inefficient sloar panel designs to only replace them in 10 years with designs that have 30% or 40% conversion efficiencies compared to maybe 20% efficiency of todays designs. Where is the greeness, and economics in that? 

Jean-David Beyer

Be careful what you read.

I read that it was not the flooding that took up the emergency generators. They were never tested properly, but just for a short time under low load conditions. When the emergency came, they started up. One quit after about an hour with a broken crankshaft. The other two did the same a little later.



I have no evidence that what I just typed is true or not. But likewise, I have no evidence that the tsunami took them out either. The problem of inadequate reporting, nervous bureaucrats covering up, and a government trying to avoid panicing the citizens, make it impossible to know what is going on.

LarryC

generator failures

 

Running diesel engines under a light load will result in 'wet stacking'.  That is when unburnt fuel collects in the exhaust system.  When the engine is fully loaded for an extended amount of time, the exhaust system heats up and the unburnt fuel is ignited.  Now you have a chimney fire plus the full load of exhaust.  It is an impressive sight, albeit a bit scary.

 

Running the generators with a full load should not lead to a crankshaft failure.  If the units where undersized, the engine would bog down and run slower, the alternator would overheat, but a catastrophic mechanical failure should not occur.

 

My speculation is that the generator's engine sucked in sea water thru the air intakes, hydrolocked, and THAT's what broke the crankshaft.  1500 rpm to zero in milliseconds.  Yeah, that is a little outside the design specs.

Jean-David Beyer

hydrolocked

"My speculation is that the generator's engine sucked in sea water thru

the air intakes, hydrolocked, and THAT's what broke the crankshaft. 

1500 rpm to zero in milliseconds.  Yeah, that is a little outside the

design specs."



I like that explanation because there could be truth both in the report I read and the more common report that the water did it. Now how would those things run for an hour with water in them? I would assume that water would take out either the crankshaft, or the connecting rods in about one revolution of the engine. (I know from second-hand experience that that is what happens when a sports car runs through too deep a puddle.) That would accord more with slowly rising water than a sudden 500 mph tsunami. But perhaps the water in the genreator rooms did rise slowly.

LarryC

Why the delay?

Now how would those things run for an hour with water in them?

 

They did not.  The water took an hour to flood the facility after the quake.  That is why the generators were running for an hour before they failed.

Gordy

Site development

 If anyone has looked closely at the close up photos/videos released lately.  I think you will find that it will be a miracle to get the systems up, and running even with newly supplied power.  Electrical, piping,controls and pumping infrastructure needs to be operable in all facets. any broken link in the chain to get water where it needs to be is complete failure.



 The mass of broken concrete, re bar, and structural steel is a sign of the magnitude of the explosions. The damage that has been done to the structure is a leading indicator of the possible damage to the cooling components of the reactors, and spent rod pools. A much more fragile mass of components in my opinion.



  If you look at the site landscape you will see why generators were flooded. The whole chain of reactors were built in a man made basin with the side to the ocean open to ground elevation. There are a number of reasons for this. Maybe to contain a radioactive spill to the site not allowing spillage to go in land, but out to sea.  Conceal the site from the in land landscape. 



  Bottom line there were plenty of areas to keep the generators high, and dry.  But were probably installed where they are for ease of maintenance, Close proximity to the power needs, and where fuel could be stored for the generators.



Gordy

Gordy

Upgrade to level 5 ???

 Same as TMI. Uhmm okay  TMI sure did not look like that mess. US War Ships 200 miles off the coast pick up radiation?

Mark Eatherton

I suspect you're right Gordy...

I think anything they do at this point in time is hand waving to appease the masses. THe human masses, because their other mass (nuclear) is beyond critical mass. I hope I am completely wrong, but for pipes, valves and fittings to be able to withstand the forces that the explosions displaced would be nothing short of a miracle in my estimation.



I heard today that they are strategizing how to bury the pools/reactor in a dirt/sand fill. Sounds like a cat trying to cover their tracks to me...



And to think, that these explosions WERE supposedly controllable, but due to lack of electrical power, their hydrogen flare igniters would not work.... Maybe we need to send Timmie Mc over there to teach them the basic of controlled combustion. I will donate the spark ignition modules.



I think it is going to get worse before it gets better.



In watching the videos, they are trying to pump water into the buildings from the ground using airplane fire fighting equipment. Why don't they send someone up those smoke stacks behind the reactor with a hose and nozzle and let them drop water IN to the hole, instead of throwing water AT the hole blindly, like they've been doing.



Desperate measures...



Pray for quick resolution.



ME

LarryC

Measuring radiation

We can measure levels of radiation that are magnitudes below levels that can cause significant biological effects.  I personally been measured by ultra sensitive radiation detectors that were shielded with pre WW II steel because any steel made after 1945 contained isotopes from the nuclear weapons explosions.

 

Just my SPECULATION, but I would make a wager that the occupants of Denver, ID, AZ, TN, and NH will recieve more radiation from their environment than anybody on the west coast will receive from Japan.

bob_46

Gordy

Gordy, did you ever run into an old fitter around Byron named Brian Beatty ?

bob

Gordy

Bob

   No I don't recall him.  There were a lot of crews that just worked the outage circuit going from plant to plant.  When I was down there the few times I worked for Westinghouse, and Blount bros. 



  I was really appalled by the amount of unprofessional craftsmenship when I worked during plant construction back in the mid 80's. Not so much the quality of work, but more how it was carried out.  The parking lot was littered with beer bottles, and fifths everywhere. The work was way over manned, and the men did not work. Seemed everything was TM.  The plants budget went up 3 fold if I remember correctly.Those were different times.  No wonder I pay 12 cents a kilowatt.



  The few times I worked in the plant I came to notice while going in, and leaving the plant not a single bird to be found ANYWHERE on the site.  Sort of an eerie feeling in my mind.  Maybe it was nothing, maybe there is deliberate animal control on the site to avoid fowling systems excuse the pun.  The eagles love the open water for food on the river though.





 Gordy



 

Gordy

Larry

 You make a good point with all the atomic weapons testing that has been done in the past above ground below ground, and out to sea. It makes this look like a smudge pot.  Its almost ironic to see the anti nuclear activists plea not in my back yard after all the testing that has been done in so many countries for 30 years post WWII isn't it.



Gordy

CMadatMe

Bury It

Bury the darn thing...Problem solved!!!! How long would that take a week or so. Did it in Russia in about a week 20 years ago. I'm getting sick and tired of hearing the news agencies now questioning if America's plant are safe. This was a natural disaster for sakes. Should we be planning to make us safe for the next ice age...Nope. We'll find someone to blame for that too.

Steve Ebels_3

Got this from Perry on the 14th

"Things are getting worse - and at least 3 of the

reactors are done for life - and have partial meltdowns; but,

containment is holding (as of last reports) so there will not be

anything approaching Chernobyl.  The question is can they save the

other 4 (and those have not yet hit the news).

A

key item is that the plants were designed for either 7.9 or 8.2

earthquake and they got hit with a 8.9   The difference between 7.9 and

8.9 is a factor of 10 (its a logarithmic scale).

Overall I'd say the plants have stood up well given what they were hit with.

As

far as the US reactors.   We have about 30 similar reactors here (GE

Boiling Water Reactors - BWR) - and many with the same vintage

containment.    Key is that very few of these are on an ocean where

they could be hit with a tsunami an hour after the earthquake (and it

was the tsunami that took out the diesel generators).

The

other 70+ reactors are Pressurized Water Reactors - and I believe that

design is inherently more capable of dealing with a total loss of power

than a BWR.

The new Generation III reactors

(for example the AP-1000 which will start construction later this year

in the US) are designed to handle a total loss of power - and have

enough passive cooling to prevent a meltdown."



I haven't heard anything in the last couple days because they are in the middle of refueling the plant he works in. ...makes him a wee bit busy.

Gordy

The difference between PWR, and BWR

Gordy

The real difference

 Is a PWR uses a HX for steam production, and a BWR the steam is a direct output from the water in the reactor. A PWR reactor is not as dirty (radioactive) as a BWR.

Gordy

DP

Gordy

Showing the vulnerable components

Gordy

Still believe

 That the systems in 3,4 and possibly 1 will actually be able to cool once power is connected?

LarryC

BWR cut away

In the picture Gordy posted labeled "Showing the vunerable components", the spent fuel pool is the pool on the upper left side.  The pool on the upper right side is where the moisture seperator parts are placed when the reactor top is removed.

 

During a refueling outage, the concrete blocks that the people are standing on in this diagram are removed and placed elsewhere on the floor.  The top of the containment vessel is removed, followed by the top of the pressure vessel.  The space between the two pools is filled up with water.  The steam drum and moisture separators are moved over to the far pool to sit during the duration of the outage.  The small red platform to the left of the drawing is used to remove the fuel bundles and place them in the spent fuel pool.  Various maintenance tasks are performed and the new and used fuel bundles are reloaded. All of the bits and pieces are reassembled and away we go.

 

Domestically, in all of the plants I have worked at, the refueling floor walls have sheet metal blow out panels that open at some low pressure (1 psi ??) in case of a steam explosion.

 

Someone brought up the concern about the pumps and piping being destroyed in the aftermath.  I doubt it.  Most of the piping and pumps would be in the lower and middle levels of the concrete reinforced structure.  I believe the primary issue is the lack of power to operate the pumps.

 

I hope this helps.