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Franco
03-11-2011, 09:42 PM
What are the chances of avoiding a meltdown and the release of radiation further than a 6 mile zone?
Paul? Anyone else?

.............


When an earthquake strikes, the plants automatically shut down, but the radioactive material continues to decay and produce heat. Reactor cooling systems, which rely on electric pumps to circulate water around the nuclear core, are designed to prevent overheating and pressure buildups.
The earthquake in Fukushima caused a power outage and damaged the plant's backup diesel generator, forcing the pumps to run on battery power. Workers have been unable to restore the systems.
Japan (http://content.usatoday.com/topics/topic/Places,+Geography/Countries/Japan)'s nuclear safety agency said pressure inside the reactor had risen to abnormal levels and radiation levels inside the facility had surged to 1,000 times more than normal.

M&K's Retrievers
03-11-2011, 10:01 PM
Sheen777 will be right with you. ;)

Marvin S
03-11-2011, 10:59 PM
What are the chances of avoiding a meltdown and the release of radiation further than a 6 mile zone?
Paul? Anyone else?

.............


When an earthquake strikes, the plants automatically shut down, but the radioactive material continues to decay and produce heat. Reactor cooling systems, which rely on electric pumps to circulate water around the nuclear core, are designed to prevent overheating and pressure buildups.
The earthquake in Fukushima caused a power outage and damaged the plant's backup diesel generator, forcing the pumps to run on battery power. Workers have been unable to restore the systems.
Japan (http://content.usatoday.com/topics/topic/Places,+Geography/Countries/Japan)'s nuclear safety agency said pressure inside the reactor had risen to abnormal levels and radiation levels inside the facility had surged to 1,000 times more than normal.

Don't think you have to be an expert - you know what happens to your car's engine when your WP goes or a hose breaks. Difference is you can shut the car off.

While I'm sure there will be solid knowledge of how to deal with the issue in the future gleaned from this, the wacko's will have a field day. 3 Mile island, anyone? No nukes in the US, again :( !!!!!!

Franco
03-11-2011, 11:17 PM
Lets hope they are right!
................


Kyodo news agency quoted the company as saying it was having difficulties opening a valve at its Daiichi reactor to release pressure.
Experts and the government both insisted there would be no radioactive disaster.
"No Chernobyl is possible at a light water reactor. Loss of coolant means a temperature rise, but it also will stop the reaction," Naoto Sekimura, a professor at the University of Tokyo, said.
"Even in the worst-case scenario, that would mean some radioactive leakage and equipment damage, but not an explosion. If venting is done carefully, there will be little leakage. Certainly not beyond the 3 km radius."

dnf777
03-12-2011, 07:14 AM
No expert here, but it I would imagine you don't normally want to see smoke plumes and explosions at your reactor sites. This was on yahoo-news today.

http://i982.photobucket.com/albums/ae306/dnf777/d5043e1191255964794522d936923803.jpg

Roger Perry
03-12-2011, 07:23 AM
No expert here, but it I would imagine you don't normally want to see smoke plumes and explosions at your reactor sites. This was on yahoo-news today.

http://i982.photobucket.com/albums/ae306/dnf777/d5043e1191255964794522d936923803.jpg

This doesn't sound good either----

There were conflicting reports about whether or not the damaged building housed the reactor.
The evacuation zone was doubled in size from 6 miles to 12 miles, Japanese broadcaster NHK reported.
Area residents were told to stay indoors, not to drink tap water and to cover their faces with masks or wet towels, according to Britain's Sky News.
"We are now trying to analyze what is behind the explosion," government spokesman Yukio Edano said.

Uncle Bill
03-12-2011, 12:39 PM
Realizing what is happening in Japan is serious, I none the less had to LOL when I saw your thread title, Franco: "Any Nuclear Accident Experts on POTUS?"...and start reading to find two of the "experts" are DNF666 and Roger. You just can't find anything more comical than that eh?

UB

Buzz
03-12-2011, 12:48 PM
"Any Nuclear Accident Experts on POTUS?"...and start reading to find two of the "experts"

UB


I wouldn't guess you'd find too many of those in any crowd.

Uncle Bill
03-12-2011, 01:08 PM
I wouldn't guess you'd find too many of those in any crowd.


As always...you are wrong again! Those two are in EVERY crowd. What rock have you been hiding under?


UB

Roger Perry
03-12-2011, 02:29 PM
Realizing what is happening in Japan is serious, I none the less had to LOL when I saw your thread title, Franco: "Any Nuclear Accident Experts on POTUS?"...and start reading to find two of the "experts" are DNF666 and Roger. You just can't find anything more comical than that eh?

UB

I see you chimed right in. You must be the nuclear expert everyone was waiting for.:rolleyes: I did not add any insite or opinion to the thread, just what was in the news. You however, are the only one here giving opinions.

Roger Perry
03-12-2011, 09:14 PM
Japan tries flooding damaged core; (http://www.msnbc.msn.com/id/42044156/ns/world_news-asiapacific/)
new emergency at another reactor (http://www.msnbc.msn.com/id/42044156/ns/world_news-asiapacific/)

This does not sound good either.

Breaking news update:
Partial meltdown at 2nd reactor reported as Japan's crisis grows (http://www.msnbc.msn.com/id/42044156/ns/world_news-asiapacific/)

Bubba
03-13-2011, 02:14 PM
Roger- MSNBC is allright as a source of information on the latest LiLO scandal but for this type of information you really need to look beyond your normal tabloid existence.

I'm no expert. I am an ex-Navy Nuc and worked in a bunch of civilian nuclear plants as well. The news reports are pretty sketchy so far but here is a relatively educated guess.

While it is true that you don't just shut off a reactor the heat produced by the decay of fission produced isotopes is pretty small in comparison to the total that the reactor can produce. Problem is that even that relatively small amount of energy needs to be dissipated or the heat will cause the water in the reactor to expand and eventually the pressure will rise to the point where the safety valves lift. This would release lots of steam (they are typically located on the top of the pressurizer in the steam space) into the reactor compartment. There would be significant contamination but none released to outside world barring damage to the containment building. Normally they would just bleed steam off from the secondary side of the steam generators and natural circulation would carry the cooler water to the reactor. Problem is that this only works until you run out of water in the steam generators. It appears that the damage to the conventional side of the plant means that their ability to pump anything is limited. Additionally if the reactor pressure valves lift it releases water that must be somehow replaced. Normally they have biggo deisel generators that power up the emergency cooling stuff but it appears these have been damaged as well.
So now you have a reactor that is very hot and no way to cool it down. If they are talking introducing sea water and Boron that likely means that they bleed the pressure down to atmospheric (or close to it) and then gravity feed in the cooling water. This water would then have to be drained to the reactor compartment. So the radiation levels inside the containment dome are sure to be way higher than normal and they may have had to vent the building to releive the steam pressure which would release small amounts of radioactivity to the atmosphere. Is it enough to be dangerous- probably not. Is it enough to get the bunny huggers MoJo running- safe bet.
So bottom line they have a massive cleanup job and given the age of the plant it will likely never return to operation (probably not a bad choice given the location). My guess is that if there are releases it will be dissipated before anyone gets seriously contaminated and little if any long term exposure risks.

The smoke and visible damage to the plant appears to be limited to the secondary portion of the plant which is nearly identical to the equipment you would find in any coal fired utility boiler. The generators are cooled with hydrogen and it doesn't take much imagination to envision a scenario where that might get exciting. Lots of BIG machinery and hot pipes everywhere. That in combination with structural damage and bunches of oil- wallah big mess. Again- a big expensive cleanup but no long term exposure risk.


I did find this article that has better information http://www.rttnews.com/Content/CanadianNews.aspx?Id=1574255&SimRec=1&Node=B1

This could actually go either way. One could make the case that this was a worst case scenario and the reactor survived as designed or that we narrowly averted a disaster. Any comparisons to 3 Mile Island or Chernobyl merely expose the ignorance of the author.

We return you now to your regular programming

Bubba

huntinman
03-13-2011, 02:22 PM
Good post Bubba. The libs are all running in circles screaming "The sky is falling"!

Roger Perry
03-13-2011, 03:44 PM
Good post Bubba. The libs are all running in circles screaming "The sky is falling"!

If the Japaneese government is anything like the Bush administration, the disaster with the nuclear power plants could be alot worse than what they are saying.

BrianW
03-13-2011, 05:16 PM
If the PM was like PBO he'd either be leaving for vacation or out playing golf! ;)

Roger Perry
03-13-2011, 07:33 PM
KORIYAMA, Japan — Japanese officials warned of a possible second explosion at a nuclear plant crippled by an earthquake and tsunami as they raced to stave off multiple reactor meltdowns, but they provided few details about whether they were making progress. More than 180,000 people have evacuated the area, and up to 160 may have been exposed to radiation.
Four nuclear plants in northeastern Japan have reported damage, but the danger appeared to be greatest at the Fukushima Daiichi nuclear complex, where one explosion occurred Saturday and a second was feared. Operators have lost the ability to cool three reactors at Daiichi and three more at another nearby complex using usual procedures, after Friday's massive quake knocked out power and the ensuing tsunami swamped backup generators.
Chief Cabinet Secretary Yukio Edano said Sunday that a hydrogen explosion could occur at Daiichi's Unit 3, the latest reactor to face a possible meltdown. That would follow a hydrogen blast Saturday in the plant's Unit 1.

By the way Brian, care to put the number of days Obama has been on vacation against the previous office holder---- Didn't think so.

huntinman
03-13-2011, 09:16 PM
KORIYAMA, Japan — Japanese officials warned of a possible second explosion at a nuclear plant crippled by an earthquake and tsunami as they raced to stave off multiple reactor meltdowns, but they provided few details about whether they were making progress. More than 180,000 people have evacuated the area, and up to 160 may have been exposed to radiation.
Four nuclear plants in northeastern Japan have reported damage, but the danger appeared to be greatest at the Fukushima Daiichi nuclear complex, where one explosion occurred Saturday and a second was feared. Operators have lost the ability to cool three reactors at Daiichi and three more at another nearby complex using usual procedures, after Friday's massive quake knocked out power and the ensuing tsunami swamped backup generators.
Chief Cabinet Secretary Yukio Edano said Sunday that a hydrogen explosion could occur at Daiichi's Unit 3, the latest reactor to face a possible meltdown. That would follow a hydrogen blast Saturday in the plant's Unit 1.

By the way Brian, care to put the number of days Obama has been on vacation against the previous office holder---- Didn't think so.

No, but he will be on permanent vacation soon Roger. We have had enough. Nov 2012... Can't come soon enough.

BrianW
03-13-2011, 09:35 PM
Stay relative. Care to track the number of days PBO was on vacation or playing golf during the BP emergency vs what the Japanese PM does during their crisis?

Roger Perry
03-13-2011, 10:44 PM
Stay relative. Care to track the number of days PBO was on vacation or playing golf during the BP emergency vs what the Japanese PM does during their crisis?

There is no comparison between the gulf oil spill and what is occuring in Japan.

Hydrogen explosion just happened at nucular plant-----

M&K's Retrievers
03-13-2011, 11:08 PM
Maybe Obama and Momma can load up a bunch of jets and go lend a hand. At least it would get them out of here for a while.

Roger Perry
03-14-2011, 07:20 AM
Maybe Obama and Momma can load up a bunch of jets and go lend a hand. At least it would get them out of here for a while.

I can't believe the hatred you have for President Obama.

road kill
03-14-2011, 07:23 AM
I can't believe the hatred you have for President Obama.


BWAAAHAHAHAHAHAHAHAHAHAHAHAHAHAHA!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!


RK

BrianW
03-14-2011, 08:30 AM
There is no comparison between the gulf oil spill and what is occuring in Japan.

I can't believe the hatred you have for President Obama.

There was also no reason, except in your hatred, to take a swipe at Bush in regards to the Japanese tragedy.
My fault for sinking to your level. I won't joust with the king of ridiculous comparisons further.

Ken Bora
03-14-2011, 08:53 AM
Mr. Perry,
Have you considered a second carrier in a waxing salon?





.

road kill
03-14-2011, 10:01 AM
No expert here, but

HAHAHAHAHAHA!!!!!!!!!!!!!!!!


RK

luvmylabs23139
03-14-2011, 10:13 AM
I can't believe the hatred you have for President Obama.

YOU HATE BUSH! So why do you have a problem with anyone who thinks Obumma is an idiot?
By the way I fully admit I hate BUMFACE.
He was playing golf while nuclear reactors are on the brink of mealtdown.:confused::confused::confused::confused:

Eric Johnson
03-14-2011, 10:29 AM
Bubba-

They are now reporting that seawater is being pumped in to alleviate the coolant loss. Two questions:

1. Would this be into the primary or secondary loop?

2. Will the seawater cause damage that can't be repaired? IOW, does the admission of seawater for purposes of cooling essentially mean that the reactor life is now zero?

Eric

M&K's Retrievers
03-14-2011, 10:36 AM
I can't believe the hatred you have for President Obama.

Roger, you are the one with the hatred. I just think he is a lying, incompetent dork who has no business in the position he holds. That's not hatred and quite frankly I would think you should be smart enough to realize the difference. Doh!!

Roger Perry
03-14-2011, 10:38 AM
There was also no reason, except in your hatred, to take a swipe at Bush in regards to the Japanese tragedy.
My fault for sinking to your level. I won't joust with the king of ridiculous comparisons further.

I was referring to the secretcy of his administration. Not the man himself.:rolleyes:

Roger Perry
03-14-2011, 10:44 AM
YOU HATE BUSH! So why do you have a problem with anyone who thinks Obumma is an idiot?
By the way I fully admit I hate BUMFACE.
He was playing golf while nuclear reactors are on the brink of mealtdown.:confused::confused::confused::confused:

And Bush did not stop reading Billy The Goat to the school children after the first plane hit the World Trade Center. What's your point??? What do you think Obama should have done differently????????????
Oh wait, since he is the Mesiah, he probably could have put his arms out and stopped the tsuanmi.

M&K's Retrievers
03-14-2011, 10:52 AM
And Bush did not stop reading Billy The Goat to the school children after the first plane hit the World Trade Center. What's your point??? What do you think Obama should have done differently????????????

You truly come up with some pretty stupid comments. Man, I hope the real estate business picks up for you.

Buzz
03-14-2011, 11:11 AM
Bubba-

They are now reporting that seawater is being pumped in to alleviate the coolant loss. Two questions:

1. Would this be into the primary or secondary loop?

2. Will the seawater cause damage that can't be repaired? IOW, does the admission of seawater for purposes of cooling essentially mean that the reactor life is now zero?

Eric

What do you mean by primary and secondary loop? I may have incorrect information, but I was under the impression that this is a Boiling Water Reactor, not a Pressurized Water Reactor.

From the little reading I've done about this, the sea water they are introducing has boron added to it. Boron is a neutron moderator. When neutrons are ejected at high energy from the nucleus of atoms that are split in the fission process, the neutrons bump into the boron atoms, draining kinetic energy from them just like a cue ball loses it's energy to the ball you're trying to sink into one of the pockets of a pool table. This tells me that they are actually introducing the water directly into the reactor vessel, I can't think of any other place they would be putting water with boron in it. It also leads me to think that one or more of the control rods did not insert when the plant shutdown was triggered during / after the earthquake. If not, the the reactor is not completely shut down.

If sea water with boron injected into it is being introduced to the reactor vessel, the plant will never operate again under any circumstances.

dnf777
03-14-2011, 01:40 PM
Here's something funny.
My one post, just to post a picture of the reactor, prompted no less than three posts from "predictable ones".

All I have to do is post once, and it generates a whole flurry of blabber!

(and I had to shake my head at the ones mocking the concern....about libs saying "the sky is falling".....never knew nuclear disasters were a lib-conservative issue??) Truly amazing how political some people are.

huntinman
03-14-2011, 02:49 PM
Here's something funny.
My one post, just to post a picture of the reactor, prompted no less than three posts from "predictable ones".

All I have to do is post once, and it generates a whole flurry of blabber!

(and I had to shake my head at the ones mocking the concern....about libs saying "the sky is falling".....never knew nuclear disasters were a lib-conservative issue??) Truly amazing how political some people are.

Well now we know one thing about DNF that we did not know before...he can count to 3! But can he handle??

road kill
03-14-2011, 03:04 PM
No expert here, but I......


Here's something funny.
My one post, just to post a picture of the reactor, prompted no less than three posts from "predictable ones".

All I have to do is post once, and it generates a whole flurry of blabber!

(and I had to shake my head at the ones mocking the concern....about libs saying "the sky is falling".....never knew nuclear disasters were a lib-conservative issue??) Truly amazing how political some people are.


"I'll give you that you are consistent.

Post after post crying out for attention, laced with personal insults and concocted anecdotes and the propensity for the over use of personal pro-nouns.

By a poster that doesn't have the kahones to walk to the line................"

RK

Eric Johnson
03-14-2011, 04:02 PM
Buzz-

I don't know the difference between a boiling water and a pressurized steam reactor.

I was under the impression that the reactor heats a fluid in the primary loop. This then passes through a secondary loop where the coolant is turned to steam to turn the turbines. What type is this?

Eric

Bubba
03-14-2011, 04:27 PM
Bubba-

They are now reporting that seawater is being pumped in to alleviate the coolant loss. Two questions:

1. Would this be into the primary or secondary loop?

2. Will the seawater cause damage that can't be repaired? IOW, does the admission of seawater for purposes of cooling essentially mean that the reactor life is now zero?

Eric

Absolute best case is that they would be pumping into the secondary loop. Problem is that it takes a lot of equipment to be operating to get that done.

In the first hours after the plant lost power the only way to dissipate the heat buildup would be to vent steam from the reactor vessel. This sounds worse than it really is, remember that steam carries LOTs of BTU's per pound (1056 BTU's per # more than water at the same temp). This will serve to help keep the reactor temperatures down somewhat but at some point they will run out of primary coolant. This means possibly uncoovering fuel cells which is a BAD thing (dramatic increase in heat buildup and radiation). So they will need to find some method of adding water back to the primary coolant system. After 40+ years you can bet that the reactor and associated piping is suffering from neutron embrittlement so adding cold water needs to be done very carefully.
My bet is that the control room is a shambles and very little if any instrumentation/controls are intact. My bet is they are pretty much operating in the blind. Tough situation especially knowing that every is done by the light of a Coleman Lantern.
If they were able to get the steam generators charged (secondary loop) then they could rely on natural circulation to help pull heat from the reactor. This is pretty iffy though due to the damage from the quake/flood/explosions. Most of the equipment in the secondary side of the plant is pretty much your garden variety industrial stuff- not intended to survive the kind of calamity visited on it. Gotta know that all the lube systems are contaminated, fuel for emergency generators is gone/contaminated. You can bet that every motor in the place is grounded/packed full of mud and the motor control centers are death traps. Cover that whole mess up with tons of debris and mud- not going to be pretty.
Introducing sea water to the primary coolant system is a last ditch measure. It's what you do to avoid becoming a Superfund site. Under normal conditions primary coolant is extremely pure water (>1 PPB contaminants) treated with chemicals to maintain a very narrow and carefully monitored pH range. The chlorides and only God knows what else in raw sea water would be nearly impossible and certainly VERY expensive to clean up. Introducing cold water is sure to warp/distort the fuel rods and there isn't a lot of allowance for that type of thing. Solid bet is that the entire coolant system is made of 316 stainless steel (possibly Inconel) both of which are highly susceptible to Chloride stress cracking - read that as game over. The secondary loop is less susceptible to damage but still - chloride stress cracking is the reason that they shut down Trojan plant (1000 MW) just up the river from here.
The good news is that the radiation levels that I have heard are high but not overwhelming. The estimate this morning was 125 mRem near the reactor. The US gooberment allows 3 Rem/quarter 5 Rem per year and that is VERY conservative. So you could work in the area for 20 hours or so and not have any effects. Any radioactivity released from the reactor containment building should dissipate very quickly and not be a big concern especially given the proximity to the ocean.
The mill that I work in is partially owned by a Japanese corporation so we have been getting some pretty good intel. At the moment they are able to generate 75% of the power needed to run the country. So they have systematic rolling blackouts and power rationing the big industries. All the bullet trains are down and getting food and supplies to all the people is difficult.

Check this out Drag your mouse from the right side of the picture to the left--you'll see the "after" hidden behind the "before" photos.
http://www.abc.net.au/news/events/japan-quake-2011/beforeafter.htm


There but for the Grace of God regards

Bubba

Roger Perry
03-14-2011, 05:10 PM
Absolute best case is that they would be pumping into the secondary loop. Problem is that it takes a lot of equipment to be operating to get that done.

In the first hours after the plant lost power the only way to dissipate the heat buildup would be to vent steam from the reactor vessel. This sounds worse than it really is, remember that steam carries LOTs of BTU's per pound (1056 BTU's per # more than water at the same temp). This will serve to help keep the reactor temperatures down somewhat but at some point they will run out of primary coolant. This means possibly uncoovering fuel cells which is a BAD thing (dramatic increase in heat buildup and radiation). So they will need to find some method of adding water back to the primary coolant system. After 40+ years you can bet that the reactor and associated piping is suffering from neutron embrittlement so adding cold water needs to be done very carefully.
My bet is that the control room is a shambles and very little if any instrumentation/controls are intact. My bet is they are pretty much operating in the blind. Tough situation especially knowing that every is done by the light of a Coleman Lantern.
If they were able to get the steam generators charged (secondary loop) then they could rely on natural circulation to help pull heat from the reactor. This is pretty iffy though due to the damage from the quake/flood/explosions. Most of the equipment in the secondary side of the plant is pretty much your garden variety industrial stuff- not intended to survive the kind of calamity visited on it. Gotta know that all the lube systems are contaminated, fuel for emergency generators is gone/contaminated. You can bet that every motor in the place is grounded/packed full of mud and the motor control centers are death traps. Cover that whole mess up with tons of debris and mud- not going to be pretty.
Introducing sea water to the primary coolant system is a last ditch measure. It's what you do to avoid becoming a Superfund site. Under normal conditions primary coolant is extremely pure water (>1 PPB contaminants) treated with chemicals to maintain a very narrow and carefully monitored pH range. The chlorides and only God knows what else in raw sea water would be nearly impossible and certainly VERY expensive to clean up. Introducing cold water is sure to warp/distort the fuel rods and there isn't a lot of allowance for that type of thing. Solid bet is that the entire coolant system is made of 316 stainless steel (possibly Inconel) both of which are highly susceptible to Chloride stress cracking - read that as game over. The secondary loop is less susceptible to damage but still - chloride stress cracking is the reason that they shut down Trojan plant (1000 MW) just up the river from here.
The good news is that the radiation levels that I have heard are high but not overwhelming. The estimate this morning was 125 mRem near the reactor. The US gooberment allows 3 Rem/quarter 5 Rem per year and that is VERY conservative. So you could work in the area for 20 hours or so and not have any effects. Any radioactivity released from the reactor containment building should dissipate very quickly and not be a big concern especially given the proximity to the ocean.
The mill that I work in is partially owned by a Japanese corporation so we have been getting some pretty good intel. At the moment they are able to generate 75% of the power needed to run the country. So they have systematic rolling blackouts and power rationing the big industries. All the bullet trains are down and getting food and supplies to all the people is difficult.

Check this out Drag your mouse from the right side of the picture to the left--you'll see the "after" hidden behind the "before" photos.
http://www.abc.net.au/news/events/japan-quake-2011/beforeafter.htm


There but for the Grace of God regards

Bubba

Bubba, the news just said that at a 3rd reactor site rods are likely melting. How long can these 3 sites last before everything fails at these sites.

Fuel rods likely melting at third Japanese reactor Water levels drop at plant's Unit 2, following similar developments at Units 1, 3

SOMA, Japan — The uranium fuel rods at a third nuclear reactor within a stricken Japanese power complex are likely to have started melting after water levels dropped precipitously twice on Monday, officials said.
The water drop left the rods no longer completely covered in cooling water, thus increasing the risk of a radiation leak and the potential for a meltdown at the Unit 2 reactor, Tokyo Electric Power Co. said.
Workers managed to raise water levels after the second drop Monday night, but they began falling for a third time, according to Naoki Kumagai, an official with Japan's Nuclear and Industrial Agency.

http://www.msnbc.msn.com/id/42066534/ns/world_news-asiapacific/

Buzz
03-14-2011, 05:29 PM
Buzz-

I don't know the difference between a boiling water and a pressurized steam reactor.

I was under the impression that the reactor heats a fluid in the primary loop. This then passes through a secondary loop where the coolant is turned to steam to turn the turbines. What type is this?

Eric


Eric, a pressurized water reactor has a secondary loop.

http://www.nrc.gov/images/reading-rm/basic-ref/students/student-pwr.gif


A boiling water reactor does not.

http://www.euronuclear.org/info/encyclopedia/images/bwr.jpg


In a boiling water reactor, the water that is heated inside of the reactor vessel and is allowed to boil, creating steam that goes through the turbines. It operates at about 1000 psi. In a pressurized water reactor, the water heated inside the reactor is used to heat the water and create steam in the secondary loop. It operates at much higher pressure, keeping the water in the reactor from boiling and turning into steam. I believe that the reactors in Japan that are in trouble are of the BWR type.

There would be no reason to inject a neutron moderator such as boron into the water unless it was being fed into the reactor vessel. The boron will reduce the energy in the "neutron flux" inside the reactor thereby slowing the reaction. We don't know if the reaction is stopped or not. I have heard it reported that it is. All of the controls and sensors are most likely destroyed. So they might not know much more about what is going on in there than we do.

Hope this helps.

Back in the 80's as part of my power engineering degree I took a series in nuclear engineering and some nuclear chemistry. But I never got into that side of the business. Looking through my old books this weekend, I realized that I've forgotten more than I ever knew about the topic. ;-) So I am trying to avoid commenting too much. I'll most likely put my foot in it, and there is more than enough misinformation already out there.

JDogger
03-14-2011, 05:47 PM
"I'll give you that you are consistent.

Post after post crying out for attention, laced with personal insults and concocted anecdotes and the propensity for the over use of personal pro-nouns.

By a poster that doesn't have the cojones to walk to the line................"

RK

fixed it for ya ;)

road kill
03-14-2011, 06:07 PM
fixed it for ya ;)
Thanks JDog, you are a very caring man.:rolleyes:

kahones: slang for balls, as in testicles.

Maybe it's a WI thang........

RK

gsc
03-14-2011, 06:16 PM
The good news is that the radiation levels that I have heard are high but not overwhelming. The estimate this morning was 125 mRem near the reactor.
Bubba

Radiation decreases to the square of the distance, or twice the distance, gives one quarter the dose. Here is some perspective.

NRC allows 5000 mrem for occupational workers per year.

At 10,000 mrem over a short period you have 1 in 30 chance of cancer.
At 50,000 to 100,000 Radiation sickness is possible.
200,00 to 450,000 Hair loss and some blood changes, some deaths within 2 to 6 weeks.
Over 450,000 half die within 30 days.
Those doses are over short periods of time, like hours to days.

No, I am not an expert, but I am a Radiation Safety Officer. This is from NRC's website.

Eric Johnson
03-14-2011, 06:39 PM
Thanks Bubba and Buzz for your extended replies. They helped us all.

Eric

JDogger
03-14-2011, 06:40 PM
Thanks JDog, you are a very caring man.


Quote:
kahones: slang for balls, as in testicles.

Maybe it's a WI thang.....

RK

Naa... it's a Spanish thang....

Jallopy-nose, ya know, the peppers, that's a WI thang....:)

...and it's good we left the nuclear accidents to the experts.

Franco
03-14-2011, 07:54 PM
Thanks Bubba and Buzz for your extended replies. They helped us all.

Eric

Yes it does.

At this point, one can only be optimistic that between the Japanesse and Americans, we can secure these nuclear reactors.

road kill
03-14-2011, 08:23 PM
Naa... it's a Spanish thang....

Jallopy-nose, ya know, the peppers, that's a WI thang....:)

...and it's good we left the nuclear accidents to the experts.

I am (was) a certified Level 1 Thermographer thru the Infraspection Institute in VM and have done infrared scans of 11 Nukes.
Scarey places.

OPPD, NPPD, Union Electric and a few other companies.
Algoma, Kewaunee, Calloway (scariest of all) and several in NE & KS and one in Spain.

But I know little about them other than Westinghouse and GE made the ones I was in.

They looked like HS science projects to me.


stan b

2tall
03-14-2011, 08:26 PM
New Blast Reported at Japanese Nuclear Plant as Workers Struggle to Cool Reactor

An explosion early Tuesday morning may have damaged the inner
steel containment vessel of the No. 2 reactor at Japan's
Fukushima Daiichi Nuclear Power Station, leading to the wide
release of radioactive materials there and forcing the
evacuation of emergency workers, the plant's operator said.

The blast appeared to be different -- and more severe -- than
those that at two other troubled reactor at the same nuclear
complex because this one, reported to have occurred at 6:14
a.m., happened in the "pressure suppression room" in the
cooling area of the reactor, raising the possibility to
damage to the reactor's containment vessel.

Goose
03-14-2011, 09:01 PM
Is Barack still golfing?

road kill
03-14-2011, 09:33 PM
Is Barack still golfing?

He is not "spending time golfing," he is "investing time golfing."

Wonderful man.....


RK

mjh345
03-14-2011, 09:59 PM
I am (was) a certified Level 1 Thermographer thru the Infraspection Institute in VM and have done infrared scans of 11 Nukes.
Scarey places.

OPPD, NPPD, Union Electric and a few other companies.
Algoma, Kewaunee, Calloway (scariest of all) and several in NE & KS and one in Spain.

But I know little about them other than Westinghouse and GE made the ones I was in.

They looked like HS science projects to me.


stan b
Stan , by Calloway I'm assuming you mean the nuke in Fulton Mo{ which is less than 100 miles from my home in Missouri}. Why is it the scariest of all?

Bubba
03-14-2011, 10:39 PM
What do you mean by primary and secondary loop? I may have incorrect information, but I was under the impression that this is a Boiling Water Reactor, not a Pressurized Water Reactor.

From the little reading I've done about this, the sea water they are introducing has boron added to it. Boron is a neutron moderator. When neutrons are ejected at high energy from the nucleus of atoms that are split in the fission process, the neutrons bump into the boron atoms, draining kinetic energy from them just like a cue ball loses it's energy to the ball you're trying to sink into one of the pockets of a pool table. This tells me that they are actually introducing the water directly into the reactor vessel, I can't think of any other place they would be putting water with boron in it. It also leads me to think that one or more of the control rods did not insert when the plant shutdown was triggered during / after the earthquake. If not, the the reactor is not completely shut down.

If sea water with boron injected into it is being introduced to the reactor vessel, the plant will never operate again under any circumstances.

Did a little more research and you are right it is a BWR. That is a horse of a completely different color and one that I'm not all that familiar with.
The Boron is actually a poison- absorbs Neutrons as opposed to moderating them. A nuclear fission reaction is sustained by "Thermal" neutrons- those that have dissipated some energy by bouncing off some other molecules (water). The control rods should have sufficient "poison" (probably Halfnium) to absorb neutrons produced in their immediate vicinity but in the event that the core becomes uncovered and things start warping and possibly even leaking the Boron should absorb the strays. This should kill the fission reaction which is where the bulk of the energy is produced.
I'm not at all sure where the hydrogen is being produced. I had assumed that the primary source was the hydrogen used to cool the generators. These units are HUGE (visualize football field sized turbine/generator) and the heat produced in the windings of the generators is off the chart. So typically the generator is designed with hollow conductors that have ultra pure water pumped through them and then the voids in the generator are filled with pure Hydrogen. Hydrogen is only explosive in a fairly narrow range of concentrations and they take special care to ensure that those conditions never exist under normal conditions.
Apparently some chemical reaction in the reactor is producing hydrogen in quantities that would explain the explosions ( I see they had yet another one tonight).
This is getting ugly but the good news is that the primary containment vessels appear to be intact. Worst case is that the fuel rods melt and release spent fuel and fission products to the reactor compartment. Really bad thing- but not the end of days.
Imagine for a second- the plant is eerily quiet except for the radiation monitors that are screaming and some few emergency lights. The vast majority of the control panels and computers that are your only source of information- dead and useless. There is NO amount of training or simulation that would be sufficient preparation. There are some brave and determined folks at work here and have my respect. Sure am glad that paper machines don't go prompt critical.

Sure glad I ain't there regards

Bubba

Buzz
03-14-2011, 11:21 PM
Sure glad I ain't there regards

Bubba

I was thinking that myself.


About the boron, I was vaguely remembering the concept of controlling the criticality of the reactor using a chemical shim instead of control rods. It's done by varying the concentration of boric acid in the water. Been a long time since I studied reactor kinetics.




I'm not at all sure where the hydrogen is being produced. I had assumed that the primary source was the hydrogen used to cool the generators. These units are HUGE (visualize football field sized turbine/generator) and the heat produced in the windings of the generators is off the chart. So typically the generator is designed with hollow conductors that have ultra pure water pumped through them and then the voids in the generator are filled with pure Hydrogen. Hydrogen is only explosive in a fairly narrow range of concentrations and they take special care to ensure that those conditions never exist under normal conditions.
Apparently some chemical reaction in the reactor is producing hydrogen in quantities that would explain the explosions ( I see they had yet another one tonight).


Bubba

Regarding the hydrogen, I looked in one of my old textbooks "Introduction to Nuclear Engineering" - Lamarsh. Conveniently enough there is a whole section on "reactor accidents." Quoting from the section on loss of coolant accidents - LOCA. The money quote is in bold.


Loss-of-Coolant Accident

Any unexpected decrease in coolant flow through a reactor core can lead to serious
consequences for the plant as a whole. Such a drop in flow can be caused by
anything from a leak in a small coolant pipe to the complete severance (sometimes
called a "guillotine" break) of a major coolant pipe. It is the latter that is the starting
point of a design basis LOCA. In a PWR plant, the break in question occurs
in one of the primary coolant loops, while in a BWR, the break is in a recirculation
loop. With the HTGR, all of the primary loops (there are four or six loops
in currently designed plants, depending on the reactor power) are located within
the prestressed concrete reactor vessel (PCRV) as indicated in Fig. 4.25. The event
corresponding to a pipe break in a PWR or BWR is the gross failure of one of the
PCRV penetration closures. Although this would lead to the rapid escape of the helium
coolant, such a LOCA for the HTGR is called a design basis depressurization
accident (DBDA).

If the containment structure is not present or is improperly designed or if the
emergency core cooling system (ECCS) is not present or is inoperable, the consequences
of a LOCA is very serious, especially for a PWR or BWR plant. To begin
with, the water is under great pressure, and on the breaking of the pipe, the water
flows out and flashes to steam. More important, in the absence of an ECCS the
uncovered fuel rods melt because of fission product heating. This, in tum, leads to
the initiation of various exothermic chemical reactions between the molten material
and the water-steam mixture, some of which produce hydrogen. Furthermore,
the pool of molten fuel and structural material at the bottom of the reactor vessel
might, in time, melt its way through the vessel, then through the concrete underlying
the reactor building, and then sink into the ground. In the United States this
phenomenon is often referred to as the China syndrome (and presumably in China
as the US syndrome), because of the ancient myth that if one digs directly downward
from a point in the United States one eventually reaches China. 19 Extensive
measures are taken to prevent a core meltdown, because of the potential for releasing
large amounts of fission products.

To avoid core meltdown and to lessen the consequences of a LOCA, as well
as the assumptions underlying the analysis of a LOCA, the ECCS and associated
systems are somewhat different for the PWR, BWR, and HTGR. Each will now be
considered, in turn.


This is yet one more piece, and I think the most damning bit of evidence that the reaction is not stopped, and that they are at least partially melting down. I'm not about to claim that the containment is completely breached.

(Sorry in advance to those who get irritated by quotes. I know it represents an inability to formulate original thought.)

Seeing this pains me to no end. Aside from the human suffering involved, it's just another black eye to the energy and nuclear energy industry. The price of our ever increasing appetite for energy is a big one.

Roger Perry
03-14-2011, 11:55 PM
A third explosion in four days rocked the earthquake-damaged plant earlier Tuesday.
Two sources told NBC News' Robert Bazell that the blast breached the containment structure and that radiation had leaked out.
The agency said the explosion may have damaged the reactor's suppression chamber, a water-filled tube at the bottom of the container that surrounds the nuclear core, said agency spokesman, Shinji Kinjo. He said that chamber is part of the container wall.
The suppression chamber is used to turn steam back into water to cool the reactor and also plays a role in removing radioactive particles from the steam.

road kill
03-15-2011, 06:29 AM
Stan , by Calloway I'm assuming you mean the nuke in Fulton Mo{ which is less than 100 miles from my home in Missouri}. Why is it the scariest of all?

Ever been there???


The neighborhood alone is scarey.;-)



RK

Goose
03-15-2011, 09:00 AM
Tokyo will be a ghost town in 6 months.

dnf777
03-15-2011, 09:55 AM
Tokyo will be a ghost town in 6 months.

Hope you're wrong.....'fraid your right.

This would certainly have effects throughout the world, given that many of flashdrives found in so many devices are made there, as well as high-tech auto components like ABS systems and fuel injection modules--even for the cars assembled in USA.

Roger Perry
03-15-2011, 11:33 AM
SOMA, Japan — The nuclear accident at an earthquake-damaged nuclear plant in Japan can now be classed as level six out of an international scale of one to seven, experts said Tuesday.

France's ASN nuclear safety authority's assessment came after Japanese Prime Minister Naoto Kan said radiation had spread from the four stricken reactors of the Fukushima Dai-ichi nuclear plant along Japan's northeastern coast.
Two reactors exploded on Tuesday at the plant after days of frantic efforts to cool them.
Level seven was used only once, for Chernobyl in Ukraine in 1986. The 1979 accident at the Three Mile Island nuclear power plant in Pennsylvania was rated a level five.

Officials in Tokyo — 150 miles to the south of the plant — said radiation in the capital was 10 times normal by evening but there was no threat to human health. Around eight hours after the explosion, the U.N. weather agency said winds were dispersing radioactive material over the Pacific Ocean, away from Japan and other Asian countries.
Radiation levels in Saitama, near Tokyo, were 40 times normal levels — not enough to cause human damage but enough to stoke panic in the bustling, ultra-modern and hyper-efficient metropolis of about 12 million people.

I am just wondering what effect the radiation materials falling in Pacific Ocean will have on the fish and other seafood there?

achiro
03-15-2011, 12:32 PM
Radiation decreases to the square of the distance, or twice the distance, gives one quarter the dose. Here is some perspective.

NRC allows 5000 mrem for occupational workers per year.

At 10,000 mrem over a short period you have 1 in 30 chance of cancer.
At 50,000 to 100,000 Radiation sickness is possible.
200,00 to 450,000 Hair loss and some blood changes, some deaths within 2 to 6 weeks.
Over 450,000 half die within 30 days.
Those doses are over short periods of time, like hours to days.

No, I am not an expert, but I am a Radiation Safety Officer. This is from NRC's website.
I'm not sure that I've got this completely figured out but help me out. If the exposure at 1 mile was 450,000mR, then at 6300 miles away(here in Oklahoma) we're looking at .001mR or .000113mSv? A CT scan is 10mSV btw.
and I ask this because I've already had patients freaking out about exposure here.:rolleyes:

Buzz
03-15-2011, 01:03 PM
I'm not sure that I've got this completely figured out but help me out. If the exposure at 1 mile was 450,000mR, then at 6300 miles away(here in Oklahoma) we're looking at .001mR or .000113mSv? A CT scan is 10mSV btw.
and I ask this because I've already had patients freaking out about exposure here.:rolleyes:


If you have a point source of say gamma rays, then the intensity of the field varies inversely as the square of the distance from the source.

Here what we are looking at is how the concentration of the radioactive effluent varies from point to point following its emission into the atmosphere.

http://i108.photobucket.com/albums/n3/davebezesky/effluent-dissipation.jpg

dnf777
03-15-2011, 01:04 PM
I'm not sure that I've got this completely figured out but help me out. If the exposure at 1 mile was 450,000mR, then at 6300 miles away(here in Oklahoma) we're looking at .001mR or .000113mSv? A CT scan is 10mSV btw.
and I ask this because I've already had patients freaking out about exposure here.:rolleyes:

Why is it, that everytime some "expert" is telling you radiation levels are safe and pose no risk, they are always far away in some studio? Just once, I'd like to see them standing in front of a blown out reactor vessel and tell us its perfectly safe. :confused: Then I may believe them.

achiro
03-15-2011, 01:14 PM
Why is it, that everytime some "expert" is telling you radiation levels are safe and pose no risk, they are always far away in some studio? Just once, I'd like to see them standing in front of a blown out reactor vessel and tell us its perfectly safe. :confused: Then I may believe them.
I would argue that a bit and say that not only are some very "top level" reporters there in Japan, there are a lot of Nuke "experts" there trying to contain things.

Roger Perry
03-15-2011, 01:33 PM
I would argue that a bit and say that not only are some very "top level" reporters there in Japan, there are a lot of Nuke "experts" there trying to contain things.

From what I have seen, the 'top level' reporters were told to back away from the danger zones. And, the Nuke "experts" really have no choice, they have to remain there to try to prevent a total meltdown.

dnf777
03-15-2011, 01:35 PM
I would argue that a bit and say that not only are some very "top level" reporters there in Japan, there are a lot of Nuke "experts" there trying to contain things.

Right. And the heros there on the grounds risking their lives trying to contain this aren't telling us to "relax, everything's ok."

gsc
03-15-2011, 02:42 PM
Let's have a little perspective.

The nukes dropped on Japan resulted in 100,000 contaminated surviors. Of that number, 500 will die prematurely for that exposure.

Of the 800,000 people effected by Chernobyl, WHO estimates that 4,000 will die from cancer due to radiation.

It is estimated that 250,000 will die in the U.S. along each year from air pollution and particulates, 20-30,000 from fossil fuel-based pollutants.

Is Japan a concern? Yes. Is it the worst disaster ever? Not even close.

gsc
03-15-2011, 02:49 PM
I'm not sure that I've got this completely figured out but help me out. If the exposure at 1 mile was 450,000mR, then at 6300 miles away(here in Oklahoma) we're looking at .001mR or .000113mSv? A CT scan is 10mSV btw.
and I ask this because I've already had patients freaking out about exposure here.:rolleyes:

I haven't seen radiation levels that high, the highest I've see was around 1000 mrem by the burning spent fuel area. But the math would be divide the dose rate by the square of the distance increase. 6300 times further away would divide the dose rate by 6300 squared. Remember, we are exposed to approx. 30-90 mircrorem coming from the environment all the time. That is solar, environmental and from consumer goods.

There is a huge problem here though. Radiation travels in a straight line unless acted upon. It would have to go through the earth to get here. Three things that reduce exposure, time, distance and shielding. The earth is a good shield. The distance is huge, and while I have a surveyl meter that can detect 0.1 micromem, this is way smaller than that.:D

Our only possible threat is from air born contamination and chernobyl didn't give us anything to worry about here, or from the bombs dropped in Japan.

Roger Perry
03-15-2011, 10:57 PM
FUKUSHIMA, Japan — Workers at a quake-damaged atomic power plant suspended operations and evacuated Wednesday after a surge in radiation made it too dangerous to remain there, dealing a setback to Japan’s frantic efforts to stem a nuclear crisis.
"All the workers there have suspended their operations. We have urged them to evacuate, and they have," Japan's chief cabinet secretary, Yukio Edano said, according to a translation by NHK television.
Edano said that a surge in radiation Wednesday meant workers were unable to continue even minimal efforts at the stricken nuclear plant.
Earlier Wednesday, a fire broke out anew at one damaged nuclear reactor, a day after the power plant emitted a burst of radiation that panicked an already edgy Japan.

This doesn't sound good at all:shock:

Buzz
03-16-2011, 09:43 AM
In the coverage I've seen on TV talking about the spent fuel rod pools, I have not seen any cutaway drawings of the plant. Thought I'd throw one up here to help folks visualize. These are cutaways of the actual GE Mark I designs.

http://i108.photobucket.com/albums/n3/davebezesky/fukashima.jpg


The new and spent fuel rods are kept in the swimming pool looking things toward the top of the drawing.

http://i108.photobucket.com/albums/n3/davebezesky/637px-BWR_Mark_I_Containment_cutaway.jpg

http://i108.photobucket.com/albums/n3/davebezesky/BWR_Mark_I_Containment_diagram.png

Franco
03-25-2011, 12:41 PM
Two weeks and it doesn't look like the situation is any better.

http://news.yahoo.com/s/ap/as_japan_earthquake

How bad could the contamination get?