Skip to comments.Japan Update: Cooling Resumed at Reactors 4 & 5 at Fukushima (Some good news for a change - maybe)
Posted on 03/18/2011 9:33:04 PM PDT by Errant
TOKYO (MNI) - Tokyo Electric Power Co (TEPCO) has succeeded Saturday in restarting an emergency diesel generator and resuming the cooling functions in Reactors 4 and 5 in its Fukushima nuclear power facility as work continued to bring power to the other reactors.
Reactors 4 and 5 at the plant are set away from the other four reactors, which sustained the most damage in the massive quake and tsunamis on March 11.
Meanwhile, workers have succeeded in attaching a power cable to the crisis-hit Fukushima nuclear power plant and are now working inside to ensure success when they switch on desperately needed cooling machinery.
"TEPCO has connected the external transmission line with the receiving point of the plant and confirmed that electricity can be supplied," the plant's operation, TEPCO said.
(Excerpt) Read more at automatedtrader.net ...
Good! I hope they can get the temperatures down quickly.
Hooray for these Japanese heroes! I hope that they can finish before the radiation does them serious harm.
I honestly don't know if it is a case of some people sensationalizing events for their own gain or just not being made of "sterner stuff" as grand-dad used to say.
I just hope Dai Ichi San is controlled, that is where the worst carp is. Reactors come, reactors go, but the ones with the spent rods are the ones to sweat at this juncture.
Cool pool, go down in temps #3.
There are some bona fide heroes in Japan tonight.
Well done, gentlemen, well done.
And thank you Lord for helping them do the impossible.
It would be about time these guys catch a break.
Yes, I had not realized how much heat is generated by the “spent” rods. And I wonder how long they have to be kept in a cooling pool.
May God be with them! Night Y’all ...
I think it's a combination of the factors you mentioned plus just plain old mark 1 ignorance. People tend to be naturally afraid of 'hidden dangers' they don't understand.
I could be wrong but I think that the writer must of meant power to reactors 5 and 6, since they are the ones that are set away from reactors 1,2,3,4 which are all in the same area.
Yes, I also think the writer meant reactors 5 and 6. That area must be where they got an emergency generator re-started.
My God! Giant mutated goldfish! Nooooooooooooooooooo!!!!!
“...that is where the worst carp is.”
Probably three eyed carp by now!
God watch over all the workers, the Japanese people, their pets and Japan.
I wondered about the spent fuel rods. Something was
said about them being on the roof of one of the buildings and I thought that rather odd. It seems to me that spent fuel rods would ordinarily be kept separated from each other to prevent an ongoing chain reaction. With that in mind, I wonder if the action of the quake caused them to come in close proximity to each other and started an unwanted reaction. Can anyone shed a little light on this.
What are the chances they’ll get any of those reactors working again anytime soon?
I hope they are not harmed too, but obviously that is not their main concern.
I read that spend rods continue to generate heat due to fission by-products, but I don’t know for how long.
The grid lines work. Great. Prayers for the guys hooking up the rest.
I think it is proper, at some point, to recognize the heroism of the engineers that have diligently stayed at their posts at fukushima and continued to work this problem. I know they’ve been working in shifts to minimize exposure... but in any case... they’re put their mission ahead of their own interest. Remember too that many of these guys have (or had) family out in the affected areas of the earthquake / tsunami and don’t know anything about their status. Kudos to them. Bravo Zulu.
1-4 are permanently toast at this point. 5 and 6 maybe salvageable.
As another poster pointed out, this MIT site covers all the bases and updates events although very clinical in descriptions still easy to understand...
Answers to your question about spent fuel rods probably found under the heading: ‘On worst case scenarios
Posted on March 17, 2011 3:55 pm UTC by mitnse’
I also have heard nuke experts wondering why the spent fuel rods are stored on top of the reactors, cost savings for the company has been the mostly likely answer.
Sorry, on page 2 at the MIT site it
addresses spent fuel rods and their ponds directly...
Lack of room at the site, is what I have read.
When there is a ... shutdown, the fission reactions essentially stop and the power drops drastically to about 7% of full power in 1 second. The power does not drop to zero because of the radioactive isotopes that remain from the prior fissioning of the fuel. ... The decay radiation then deposits most of its energy in the fuel, and this is what is referred to as decay heat. As these radioactive isotopes continue to decay, more and more of them reach a stable state and stop emitting radiation, and thus no longer contribute to the decay heat.See chart and table at link.
The reactor decay heat is now down to less than 0.5% of the normal power. But that is still about 10 Mega Watts of heat to remove from each reactor to maintain temperature. Even after a year it's still about 5 MW.
Spent nuclear fuel (SNF) refers to fuel after it has fueled a reactor. ... SNF contains fission products ... which are radioactive, meaning it needs to be shielded. ... The SNF also needs to be cooled, but at a much lower level than fuel in a recently (<12 hours) shutdown reactor as it produces only a fraction of the heat. In summary, the SNF is stored for a certain time to: 1) allow the fuel to cool as its decay heat decreases; and 2) shield the emitted radiation.
These pools are ... often 40 feet deep ... The pools are made of thick concrete, lined with stainless steel. SNF assemblies are placed in racks at the bottom of these pools, so almost 30 feet of water covers the top of the SNF assemblies. The assemblies are often separated by plates containing boron which ensure a neutron chain reaction cannot start. The likelihood of such an event is further reduced because the useful uranium in the fuel has been depleted when it was in the reactor, so it is no longer capable of sustaining a chain reaction. ... The heat is rejected through a heat exchanger in the pool so the pool should stay at fairly constant average temperature. The water depth also ensures the radiation emitted from the SNF is shielded to a level where people can safely work around the pools.
Just so you all can sleep well at night. Since Carter cut off the reprocessing of spent fuel rods and since Obama wouldn’t allow Yucca Flats to be activated, all spent fuel rods from the last 25 years of operation are still sitting in similiar pools at US plants. Not secure inside a containment vessel.
I think it's just an old design. At the link I posted above it explains that they flood the area between the spent fuel pool and the reactor core with water to move fuel into and out of the core. So proximity is needed during this phase.
Newer designs may have below ground level storage for spent fuel.
I've also seen speculation that the pools that are heating up may have small water leaks causing the loss of cooling water.
Newer designs still have the spent fuel pool at an elevation that allows a horizontal transfer of the fuel rods between the reactor and the fuel pool.
Likely because the reactors are loaded and unloaded from the top.
So the top is where they are stored. For example reactor 4 was unloaded for maintenance, all the rods were in the storage pool. Having to move the rods a long distance to store them elsewhere would likely greatly increase the possibility of an accident while moving them.
That said, on top still seems dangerous... A melt down in the pool melts down to the reactor below. Though on the other hand, a melt down in the pool is probably worse than a meltdown in the reactor... There’s more fuel in the pool...
Those reactor cube buildings are about 150’ wide (or half a football field) to give some perspective... That’s pretty darn large...
Optimus Prime (Peter Cullen) said that in the animated Transformers movie in 1986. Love that line.
Simpsons did it.
These pools also store fuel that is not spent. When reactors are shut down for maintenance the fuel is temporarily stored in these pools while the reactor is being worked on.
Reactor #4 is a case and point. It was shut down for maintenance and its fuel rods stored in the adjacent pool above it.
sensationalism equals ratings—its as simple as that.
Earthquake zone is why the rods are above...concern that in ground could fracture the container....or something like that....There was a piece about why they opted for above ground.
Second floor fuel rod pond is a feature of GE Mark I and Mark II regardless of where the reactor is located.
I got the impression that they were spent fuel rods. Were they then moved for additional cooling? I have no idea.
I don't know how accurate that information is nor do I have any expertise about nuclear plants.
Actually I think it is much higher than the 2nd floor as the elevator sees it — can’t remember how many stories.
The post did say that water had to be circulated around them for the entire 14 years.
I don’t know why, but I think this is going to turn out like the gulf oil spill; one day it’s the worst environmental disaster known to mankind, yet the next day we discover it was all hyped out of proportion in order to sell otherwise unsellable advertising space on “news” media.
As long as it promotes the agenda to keep our republic energy dependent on others, it will shine in the media. Should this dragon be conquered, it will disappear as quickly from the media’s eye as rapidly as the tens of thousands who have perished in the tsunami...
It is as you say Mrsixpack. This is another great disaster, like Three Mile Island, with enormous press coverage, most of it misinformed, where no one is hurt from the nuclear characteristic of the plant. No power technology comes close to the safety record - not level of hysterics - measured by the number of people injured in megawatt hours/person. When the data are available it appears that commercial nuclear power will not have killed a single person in its 60+ years from exposure to radiation.
Chernoble was not a commercial reactor, a design with no containment whatsoever, and so the the one or two direct deaths from radiation should not be included in risks for commercial reactors. But even with Chernoble, which caused more injury by being off line, since its replacement power came from coal, no electricity generation technology comes close. Most deleterious health effects from Chernoble were a result of the forced evacuation. Livestock and animals living in "contaminated" fields near the Chernoble reactor, while they have slightly increased levels of radiation in their bones, are healthier than the average in surrounding Ukrainian towns.
All active Fukushima reactors’ control rods were inserted within seconds of the earthquake. They could all have melted down and the result would have been the same. Containments were designed anticipating a worst case. The cores are, of course, through producing commercial power. The tsunami eliminated the backup diesel generators making the cool-down other than quiet; but dissipating the remaining energy was always manageable.
New reactor designs are even more robust. The conservatism of nuclear engineering after half a dozen meltdowns, a couple of them total, proves the remarkable foresight of the design engineers. The siting of diesel backup in coastal installations will surely be examined.
Most of the “experts” asked to speak by mainstream media make livings as consultants, not as engineers. The money in the U.S. is in the anti-nuclear business. There are families of environmental attorneys where a husband and wife each work for the other side, and are paid very well by taxpayers to express the fear, or the wish to return the U.S. to a subsistence society, growing vegetables in our little gardens with solar heated bathing water and windmills to grind our grain. They would never get another call if they expressed confidence in the decades of design which went into 1970 designs.
The most dangerous aspect of nuclear reactors occurs when they are off line. Every other source of energy is more dangerous, and coal, the usual source of replacement electrical energy causes about 200 additional deaths/year for each thousand megawatt plant from respiratory-related illness. Ironically, coal plants usually don't meet NRC standards for nucleotide emission. Coal, having been dug from the ground, has varying amounts of natural uranium and radium which is not scrubbed from the Co2-filled combustion product.
I honestly don’t know if it is a case of some people sensationalizing events for their own gain or just not being made of “sterner stuff” as grand-dad used to say.
Given a plain look at the state of American education today - what passes for education at least - I would say that both are correct.
You got it. The Japanese have just given the world an example of grace and gallantry under extreme circumstances which is a wondrous contrast with what the world saw in New Orleans six years ago.
From a 2004 FR post:
After years of problems and delays, Japan’s power industry has taken a major step toward its long-cherished dream of using plutonium as fuel for conventional nuclear reactors.
The breakthrough came when Fukui Prefecture recently approved a plan by Kansai Electric Power Co. plan to purchase plutonium-uranium mixed-oxide (MOX) fuel from overseas to burn in reactors at its nuclear power plant in Takahama, a town along the Sea of Japan coast. The power company hopes its pluthermal operations will begin in 2007.
Kansai Electric was forced to shelve the project in 1999 following revelations that British Nuclear Fuels, the supplier of MOX fuel, had falsified data. Kansai Electric says it will select its supplier of MOX fuel carefully after taking necessary steps to enhance its system for fuel quality control.
The concern is the MOX (processed Plutionium laced fuel rods)