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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.
Last edited by Buzz; 03-14-2011 at 11:30 AM.
"For everyone to whom much is given, of him shall much be required." -- Luke 12:48
Raven - Moneybird's Black Magic Marker***
(Esprit's Power Play x Trumarc's Lean Cuisine)
Mick - Moneybird's Jumpin' Jack Flash***
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Peerless - Moneybird's Sole Survivor
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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.
God Bless PFC Jamie Harkness. The US Army's newest PFC, but still our neighbor's little girl!
Originally Posted by dnf777
"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
Last edited by road kill; 03-14-2011 at 04:35 PM.
stan b
SR-HR-UH-Field of Dreams Mr. Elvis
"Don't give up.....don't ever give up!!!"
Jimmy V
__________________________________________________ ____________________
"Do not go where the path may lead, go instead where there is no path and leave a trail."
Ralph Waldo Emerson
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
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/ja...eforeafter.htm
There but for the Grace of God regards
Bubba
"During my lifetime most of the problems the world has faced have come, in one fashion or other, from mainland Europe, and the solutions from outside it."
Margaret Thatcher
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...s-asiapacific/
Eric, a pressurized water reactor has a secondary loop.
A boiling water reactor does not.
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.
Last edited by Buzz; 03-14-2011 at 05:57 PM.
"For everyone to whom much is given, of him shall much be required." -- Luke 12:48
Raven - Moneybird's Black Magic Marker***
(Esprit's Power Play x Trumarc's Lean Cuisine)
Mick - Moneybird's Jumpin' Jack Flash***
(Clubmead's Road Warrior x Oakdale Whitewater Devil Dog)
Peerless - Moneybird's Sole Survivor
(Two River's Lucky Willie x Moneybird's Black Magic Marker)