25th Anniversary Of Three Mile Island 418
fbform writes "March 28, 2004 is the 25th anniversary of the Loss Of Coolant Accident (LOCA) at the nuclear power plant on Three Mile Island, Pennsylvania. It's a good time to reflect on the impact it has had on our nuclear safety policy and interface design in general."
Wikipedia articles on TMI (Score:5, Informative)
Three Mile Island [wikipedia.org]
List of nuclear accidents [wikipedia.org]
Shame (Score:5, Insightful)
The truth is that modern techniques could probably make nuclear power an extremely safe alternative.
Re:Shame (Score:5, Informative)
Especially pebble bed reactors [wikipedia.org].
Re:Shame (Score:4, Insightful)
But there is still the waste disposal problem. Until we have a solution for the disposal of the higher-level waste that is in place and shown to be working, I for one will not be supporting nuclear powery.
I parsonally am not happy with long term repositories such as Yucca Mountain - too many unknowns. My favoured version was the subduction zone disposal - return it to the earth's core, which is used to it. Does anybody know why this disappeared off the map?
You evil man!!! (Score:5, Funny)
People like you make me sick.
Flamebait? (Score:2)
Re:You evil man!!! (Score:2, Interesting)
Re:You evil man!!! (Score:4, Informative)
Re:Shame (Score:2, Insightful)
You'd have to ditch the radwaste casks in the ocean, where they might be prone to leaking in a harsh, high pressure ocean environment. I suppose if the radwaste is significantly heavier than the water so it won't float, and it can be dropped into a trench so any leaking has no chance of washing up, it would be a viable idea.
Re:Shame (Score:3, Funny)
Isn't radiation in the ocean just the sort of foolish plan that results in disatrous consequences? I seem to recall seeing a documentary with Raymond Burr about nuclear tests in the p
Re:Shame (Score:3, Funny)
On March 1st, 1954, the US exploded H-bomb Bravo on Bikini. Radioactive ash fell on the Japanese fishing boat "The Lucky Dragon No. 5", and Bravo's nuclear hurricane engulfed Rongelap. Children played in the "snow", and then began screaming as it burned and poisoned them. The Japanese newspapers ran with th
Re:Shame (Score:5, Funny)
Because the best subduction zone on the planet is the Marianas Trench off the east coast of Japan. And we all know why dumping radioactive material off the coast of Japan is bad [imdb.com].
Re:Shame (Score:3, Interesting)
It's very poisonous but there's not that much of it. As long as the dangers are less than the dangers of other technologies and less than the dangers of not having electricity then fission is the prudent choice.
Incidentally, mercury is toxic forever and coal plants are disposing of it in people's lungs.
Re:Shame (Score:5, Interesting)
At this point, I'd put a dog on a treadmill generator to not have coal power though...or an ignorance-rutting politician.
--degs at 68k dot org
Re:Shame (Score:4, Insightful)
If nuclear reactors were mass produced, then making a "farm" of smaller units would make sense. But they are not. The navy uses small reactors because they have to fit into the boat and still have enough room for everything else.
So when building individual units - bigger = more power for your money. Economics. Plus, nearly all of the engineering work for building a regular plant has been completely worked out, which means you have a set of plans that you know works. Why fix what isn't broken?
Now, if you could come up with a way to build a modular nuclear station with cost-per-megawatt lower than a traditional plant, you might get someone to listen. Then you have to convince people that it's just as effective, which means getting someone to pay for the first plant wil be a challange. Once you've got your foot in the door it might be a little easier, though.
=Smidge=
Re:Shame (Score:5, Informative)
Re:Shame (Score:3, Informative)
Not to pick but as a former MM on the Enterprise she was originally designed, and currently contains 8 reactors [navsource.org]. All Nimitz class carriers contain 2 reactors [navsource.org].
You are correct that each reactor could power a small city. The prototype I attended in Idaho at the INEL (now INEEL) [inel.gov] actually supplied power from the A1W and S1W reactors to a small local city. The power companies did not like this and had congress stop this in the 60s.
Additionally, as of this posting, no one has mentioned that the Navy's reactor
Re:Shame (Score:3, Informative)
There's 7 incidents we know about. Given the secrecy of the military who knows if there's more that we don't.
from: http://en.wikipedia.org/wiki/Nuclear_disaster
1954 - The submarine USS Seawolf (SSN-575) scuttles an experimental sodium-cooled reactor in 9,000 ft (2,700 m) of water off the Delaware/Maryland coast. At 33 kCi it's likely the most radioactive single object ever deliberately sunk, and has not bee
Size doesn't matter (Score:3, Insightful)
It would seem that safety is
Re:Shame (Score:4, Interesting)
Re:Shame (Score:4, Interesting)
Energy policy has a big impact on the environment if global warming is directly linked to the burning of fossil fuel. Nuclear power may ironicaly have a lower impact on the environment in the long term if we solve the problem of waste recycling. Radioactive materials are dug out of the ground so it does not seem impossible to put them safely back into the ground. Exhaustion of fossil fuel will automatically drive greater use of water wind and wave power but only policy will drive the use of technologically sophisticated power sources like fusion and nuclear power.
Re:Viability of LSLT nuclear energy? (Score:4, Informative)
www.bnfl.com [bnfl.com]
Sorry about the lack of detail, but I couldn't find anything more specific on their site.
Re:Viability of LSLT nuclear energy? (Score:3, Interesting)
The incoming also creates a small amount of 'heavy water' in the oceans. The creation process I've been told is forever as long as the sun shines, and has long ago, as in billions of years, reached an equalibrium point. If a reactor could be designed to make use of this, it would only take a lead pencil sized stream of this heavy water to power every currently fossil fueled device on the planet. In simpler terms, we have enough
Re:Viability of LSLT nuclear energy? (Score:3, Informative)
The "apparently benign gas" you are referring to is radioactive helium. It's benign in that 1. We're talking about radiation levels of 1/1,000th or so of the more serious fission byproducts. 2. Helium is chemically inert, so living things can't incorporate it into their tissues and it can't be
Re:Shame (Score:5, Insightful)
It is a shame that sloppy and incompetent management by the nuclear power industry has created an entirely justified bad image.
The big lie told about three mile island was that the design is 'failsafe'. As a matter of definition it is not, no light water reactor design is. Failsafe means that if something breaks it breaks in a safe way. Three mile island had redundant safety systems, that is not the same thing.
The truth is that modern techniques could probably make nuclear power an extremely safe alternative.
The truth is that the better designs of forty years ago could have made safe nuclear power. The CANDU heavy water system is genuinely fail-safe. The coolant doubles as the moderator. That means if you loose one you loose the other and the reaction is halted.
Today there are vastly better designs, like the pebble bed reactor that MIT and others have been looking at.
The real problem is not technical, it is political. The concerns about nuclear power are completely justified. The nuclear industry has lied and deceived in the past. In the UK there was a long history of accidents, coverups and blatant deception. The true economics of nuclear power only became apparent after the Thatcher government tried to privatise nuclear power. When the books were opened it turned out that nuclear power had been vastly more expensive than claimed - and there are still the costs of decommissioning the plants.
Research into new types of nuclear reactor are required for many reasons. Even the idiots who ignore global warming see that energy reserves are running low. If we do not start looking at better nuclear options now we may end up being forced into repeating the light water mistake.
Re:Shame (Score:4, Informative)
The statement "(t)he coolant doubles as the moderator" is also true of American light-water designs.
CANDU system info (Score:3, Informative)
So, because there's less energy per gram, CANDU system have online fueling, which means that the reactor
Re:Shame (Score:3, Informative)
Yeah, yeah, I have a doctorate from Oxford Univ. Nuclear Physics Lab. Where is yours from? I have also worked as a control engineer.
From your tone you sound like an ex-nuclear power employee who just has to spend their time writing self-justifications on the Internet. Sorry, you have no more credibility with me than the rentacops who used to do airport secur
Re:Shame (Score:4, Insightful)
The links in question connect to people who live near to TMI and were affected. I think that calling people who have been lied to and betrayed as they have 'paranoid' or 'phobic' is disgusting.
As I keep saying, look at the people, look at the tactics. It is possible that they are merely trolls or agent provocateurs from greanpeace, but I doubt it. It was exactly this type of attitude, that the only reason someone would doubt nuclear power would be if they were an imbecile that causes me to not trust them.
None of the profs I at any of the labs I have worked with would endorse your position. Even Teller, who I never met but was frequently compared to (for proposed applications, not insight into physics) would not endorse your position. You are asking for blind faith.
I am a scientist, blind faith is something I try to eliminate.
One final point. The worst effect the nuclear mafia had on energy policy was their ruthless campaigns to kill studies of 'alternative energy'. When I visisted Rutherford Appleton Labs the folk there were very upset about the way Salter's duck, a promising wave power technology was sunk by outright deception by the fanatically pro-nuclear 'review board'. They could not even bear to see the idea of alternative energy sources being examined. When the true costs of nuclear power came out during the privatisation fiasco it turned out that Salter's duck would have produced energy at half the real cost of nuclear - even with the ridiculously inflated costings used.
Re:Shame (Score:3, Insightful)
If the plant can separate the tritium from the duterium why throw it away? Considering that it might come in useful for building hydrogen bombs.
Re:Shame (Score:5, Interesting)
What do you mean "could"?
In terms of lives lost, damage done, or just about any other measure you care to name, provided you restrict yourself to a competent design, nuclear fission is ALREADY the safest power generation technology known to man. Read "The Health Hazards of NOT Going Nuclear" by Dr. Petr Beckmann.
The key phrase in that sentence is "competent design." One of the key parameters in any nuclear reactor design is the void coefficient, and, most particularly, the sign of the void coefficient.
From http://www.nrc.gov/reading-rm/basic-ref/glossary/
From http://www.disenchanted.com/dis/lookup.html?node=
Briefly, if a reactor is designed with a positive void coefficient, it will inherently have a risk of a Chernobyl-style thermal runaway. If a reactor is designed with a negative void coefficient, it will not have that particular hazard. This fact was known to the Soviet reactor designers, who designed the RBMK reactor at Chernobyl (among other places), and was also known the US designers who wrote the US standards for reactor design. Positive void coefficient designs are flat-out illegal in the United States.
To do the safety analysis, you have to take, for example, black lung deaths of coal miners into account, and supertanker oil spill environmental damage. You also have to take into account the number of people who will, while attempting to install solar water heating panels on their roofs, will slip, fall, and break their necks.
If you want to prattle about radiation hazards, bear in mind that every lump of coal you burn, every drop of oil, every cubic foot of natural gas, contains some amount of radioactive carbon-14, and the ash (and emitted CO2) is thus radioactive waste. Ditto for wood. (Wood smoke contains other nasty things.)
So if coal and is bad too... (Score:3, Informative)
However, you got one thing wrong with fossil fuels. They don't contain radioactive carbon-14 (C-14). C-14 is steadily produced in the the upper parts of the athmosphere by cosmic radiation bombarding nitrogen atoms. C-14 has a half life of ~5730 years, and any C-14 in the original organic material that formed oil and coal millions of years ago is long gone. That's
Re:So if coal and is bad too... (Score:3, Informative)
Bluntly, you get days when the wind don't blow and the sun don't shine.
Even on days when the wind does blow, you are inherently looking at very low conversion efficiencies. (Fundamental thermodynamics, worked out by a fellow named Carnot, quite a few years ago.)
On days when the sun DOES shine, you are STILL limited to about 1.3 kW/sq meter absolute maximum. Photovoltaic conversion runs, last I heard, abo
Re:Shame (Score:3, Interesting)
Wrong. Since the DNA molecule has a carbon based backbone, the chance of a C 14 decay causing a mutation is 10
Your ignorance is a shame. (Score:5, Informative)
Including the people who work there.
Nuclear Power is perfectly safe when done right, and it's done right in the US. The worst that could happen in the US in an accident condition is that parts of the power plant are destroyed. And for even that to happen, so many very closely watched things would have to go wrong that it's basically not going to happen.
So shut off your lights if you don't like nuclear power, and go back to your cave.
Re:Your ignorance is a shame. (Score:3, Interesting)
The Twin Towers were also perfectly safe buildings that could never collapse. Not on their own, anyway. But we are living now in a totally different century. The one in which modern technolog
Blah. (Score:3, Interesting)
Now, as for nuclear plants: do you really think noone has ever considered the possibility of an attempt to blow up a nuclear plant? Well, maybe noone has and they really have been completely unguarded until recently, but I don't buy it. I'm quite sure they were possible targets for Soviet saboteurs; surely the US and European
Re:Blah. (Score:4, Insightful)
The situation is indeed different. E.g. it was said for the last 30 years or so that Germany's nuclear plants would be completely safe against aircrashs, terrorist attackes, malfunction, even most kinds of military activities. However, recent studies undertaken on behalf of the German government had the result that none of Germany's nuclear power stations would be able to withstand the direct impact of a large airliner without considerable damage, some of them would even be catastrophically destroyed.
How could this happen ? On one hand, when those plants were built between the 60s and 80s, terrorist activity was understood mostly as single bombs or sabotage as was commonly acted out by the left-wing terrorist of the time. Attacks of 9/11 or Madrid scale or suicide attacks of the kind we see in the middle east were unthinkable back then. It was also thought that the Red Army would not see to actively destroy nuclear power stations as they wanted to make use of land they conquered. Regarding aircrashs, the problem is similar to the planning parameters of the Twin Towers. On one hand everyone assumed an air crash to happen by accident, so mostly fast but small military aircraft were taken into account. On the other hand, the largest commercial aircraft when a lot of these plants were planned were Boing 707 and the like, which apparently could cause much less damage than modern aircraft.
The problem with long-lived technologies like nuclear energy is that in a couple of decades a lot of key parameters regarding the security of them can drastically change.
Terrorism and nuclear facilities (Score:5, Informative)
They have no-fly zones around nuclear plants now. Not really because flying inside the line gets you shot down, but so they can aim a SAM at an incoming threat without worrying about hitting the wrong plane (not that they're worried about hitting the wrong plane - it's really that they're worried about missing the right one).
So let's pretend we're mad as hell and not going to take it any more. What's the plan?
9/11 style air attack won't work. You'll either get SAMed or the containment building will likely survive the impact.
Armed assault will be met with armed resistance. The minute the attack starts, someone presses the panic button and the cavalry arrives.
No, the only credible terrorist threat in my mind is an inside job - someone gets a job as a plant worker and sabotages the plant. If the plant were a fail-safe design, however (as a previous posted pointed out, current plants are designed with redundant systems, but are not fail-safe), the worst the criminal could do is shut the plant down and perhaps try and disperse the fuel with explosives (note that due to a failsafe system, he won't get any help dispersing the fuel from the plant itself). His ability to smuggle explosives into the plant without being detected will limit the effectiveness of that plan. Never mind that he'd have to be able to breach the containment building (yes, even a fail-safe reactor will likely have one).
Sabotage is certainly a threat at current nuclear facilities, just as it is a threat at, for example, petrolium refineries (I'd actually put Richmond, CA ahead of, say, San Onofre on a threat list). Better design mitigates that risk, just as it mitigates so many other risks.
Re:Your ignorance is a shame. (Score:3, Insightful)
Re:Your ignorance is a shame. (Score:3, Insightful)
They wanted immediate casualties, a high body count. They wanted TV coverage of bloody people. Their supporters in the Arab Street do not understand radiological poisoning. Seeing an empty NCY would be good, but seeing distruction is better. The images of the mighty americans fleeing the center of power must have put them into fits of ex
Re:Your ignorance is a shame. (Score:3, Informative)
Yeah, I actually sort of feel safer flying now; the only useful thing left that terrorists can do with airplanes (in the US at least) is blow them up, and there are many easier ways to make your point than blowing up an airplane. If anybody tried to hijack a plane now, I suspect they wouldn't last five minutes. Which probably isn't so much patriotism at work, b
Re:Your ignorance is a shame. (Score:3, Funny)
Slogan: Nuclear power, possibly safer than smoking.
Re:Nuclear power industry not safe. (Score:5, Insightful)
Nothing is completely safe. Thing is, the alternatives - the real, viable alternatives -- to nuclear power are even less safe.
You may recall the recent FDA advisory [fda.gov] warning pregnant women and children to limit their intake of several types of fish because of mercury contamination in those fish.
The FDA guidelines call for children and pregnant women -- and women who "may become pregnant" to abstain completely from shark, swordfish, king mackerel, or tilefish, and to limit intake to six onces of albacore tuna a week.
What you might not have heard is that the panel that made the recommendation contained two members who were former lobbyists for the fishing industry [alternet.org] -- or that another member, a scientist, not a lobbyist, resigned in protest because he believes that even six onces a week of albacore tuna is dangerous, and that that recommendation was only made because of industry lobbying.
What you also might not have heard is that the primary source of mercury in fish is from "mercury rain" -- and the primary source of mercury rain is from coal fired power plants
As it happens, the EPA is retreating from plans to more closely regulate mercury pollution from power plants, and "just coincidently" some of the language justifying that retreat is word-for-word the same as language in utility company memos.
So on the one hand, the fishing industry influences the FDA to soft-pedal its warnings to children and pregnant women, and on the other hand the power industry gets the EPA to continue to allow pollution.
And this is not to mention the other dangers of coal: despoiling the environment by digging it up, despoiling the air with smog when it's burnt, giving miners black-lung, etc.
I grew up a few miles from Three Mile Island, and I was still there when the accident happened, and I'll take clean nuclear power any day. Even in the worst case, we can contain a nuclear plant accident -- but we can't contain an ocean of mercury contaminated fish.
Re:Nuclear power industry not safe. (Score:3, Insightful)
Demand-side management, renewables and co-generation should be considered. While none are perfect, they are much cheaper and don't have some of the liabilities of nuclear energy.
*energy production* not safe. (Score:3, Insightful)
Re:*energy production* not safe. (Score:3, Insightful)
americans are fam
Re:Nuclear power industry not safe. (Score:3, Interesting)
And Vice Versa - Possible deaths from truck-car accidents involving trucks transporting nuclear fuel have routinely been included in estimates of the risks from nuclear power, while being omitted from coal.
Re:Nuclear power industry not safe. (Score:3, Insightful)
Stop and pause (Score:3, Insightful)
Re:Stop and pause (Score:5, Informative)
TMI was much more of a true accident. A valve malfunctioned to start the whole thing, something that didnt require a direct human action to occur.
Re:Stop and pause (Score:3, Insightful)
Cheers, Gene
Re:Stop and pause (Score:5, Informative)
TMI was a case of automatic safety systems being overrided by undertrained human operators. As the story paragraph mentioned, TMI was a stark lesson in control systems design.
In the control room the operators had no feedback about how much water was in the reactor core, just one gauge showing the level of water in the pressurizer tank near the top of the system. When a valve near the top of the pressurizer stuck open (referred to as the PORV or pressure operated relief value) the steam that normally kept the water near the bottom of the pressuizer tank started leaking out. More water flashes to steam.... and TMI is now losing water. The operators saw the opposite, the water level was rising on the level gauge for the pressurizer and they started reducing and eventually draining water out of the system thinking some malfunction was causing water to be introduced. None of the operators was able to step back from the initial theory that water levels were rising, despite large amounts of contradicting information. (Hours into the incident an off-duty operator arrived and with a fresh set of eyes figured out what was happening)
There are a lot more things that went wrong that night... (the initial shutdown was caused by water accidentially getting into the compressed air supply for the pneumatic control systems in the steam room, a valve closed at the wrong time and burst one of the steam lines to the power turbines)
TMI is a fascinating example of how multiple redundant systems still can fail, given a long string of "coincidences" One can argue that failures of this type are like winning the lotto, their is little chance of it happening on on particular day, but given enough days it is certain to happen to someone. Hence the need for "fail safe" designs.
Re:Stop and pause (Score:5, Insightful)
Very true. It allows us to realize how fortunate it is that our engineers rejected the open-pile design which caused Chernobyl to be so dangerous. It also makes me thankful that, due to the skillful design, the TMI incident is a disaster only in the terms of public-relations among those who don't understand, or want to understand the science.
I don't think that anyone who isn't rabidly anti-nuclear power would consider these to events to be anywhere near equivalent. It says a lot for the systems that, despite the chain of human and mechanical failures, the incident at TMI was limited to such a small environmental impact. That wasn't by luck, it was by design decisions, choosing a much safer way to use nuclear energy to create power.
Bringing Chernobyl into the context of TMI shows that the person doing so either doesn't understand the science, or is trying to use fear of Chernobyl to convince others who don't understand the differences.
Re:Stop and pause (Score:5, Informative)
No, that's simply not true.
Union Carbide in Bhopal: 3000 to 8000 dead; over 100000 injured.
Chisso Corporation at Minimata: mercury poisoning kills hundreds, with at least 3000 people afflicted.
The Grandcamp in Texas: Fertilizer explosion kills nearly 600; over 3500 injured.
Chernobyl: fewer than 100 deaths to date; fewer than 1500 known attributable radiation-related illnesses. Potential premature deaths due to excess radiation exposure estimated to be 3000, but we'll have to wait and see.
Nuclear power is dangerous, but there's a lot worse out there. Look up deaths attributable to coal-fired power plants sometime.
Re:Stop and pause (Score:4, Informative)
Dam failure in China, 80,000 dead.
You don't even want to think about worst-case failures of LNG tankers.
Re:Stop and pause (Score:3, Interesting)
Indeed. I was only 5 when TMI happened, and while I don't remember hearing about it from my parents back then, I do remember hearing about it in 1986, when news reports of Chernobyl got them talking about the TMI incident and how worried they were in '79. Thanks to the west-to-east weather patterns, a meltdown at TMI would very probably have affected Philadelphia, 90 miles away. It would definitely have obliterated the state gover
Fusion (Score:5, Informative)
Re:Fusion (Score:5, Funny)
Don't know about you, but the Mahavishnu Orchestra surges more energy in me than any power source could!
Re:Fusion (Score:4, Interesting)
Re:Fusion (Score:2)
Oh little isle, of 3 Mile... (Score:4, Funny)
Above the town of Middletown, the glowing clouds scud by.
Yet in thy dark streets shineth, the everlasting glow.
We'll all mutate, and radiate. And then we'll die, you know"
Re:Oh little isle, of 3 Mile... (Score:3, Insightful)
How such horrible, idiotic poetry could be modded up is beyond me.
Incidentally, TMI's miniscule radiation release was projected to cause less than 1 extra death for the hundreds of thousands of people potentially exposed. INCL
Re:Oh little isle, of 3 Mile... (Score:3, Funny)
Consequences of cheap nuclear power? (Score:5, Insightful)
I noticed recently that in Arizona so few people have clotheslines. It is 100 degrees and sunny for most of the year there, but most people still seem to dry their clothes in the electric clothes dryer.
That approach is not as common in Australia, where we take advantage of 100 degrees of sunshine to get our clothes nice and dry.
Are we weird, or what?
Re:Consequences of cheap nuclear power? (Score:4, Funny)
Re:Consequences of cheap nuclear power? (Score:2, Insightful)
Re:Consequences of cheap nuclear power? (Score:3, Informative)
Austrailia must not have HOAs (Home Owners Associations) similar to those in the U.S.?
It took ages for my friend from Arizona to explain HOAs to me. At first I thought he was talking about a kind of a vigilante action group. Here we just have a local council of elected officials that make up housing regulations.
They generally let people access the sun using ropes for the purpose of drying their washing.
Arizona (Score:3, Funny)
Re:Consequences of cheap nuclear power? (Score:2, Funny)
As for drying your clothes outside, it fades your clothes very fast. It is hot and dry enough in AZ that all you need to do is put your clothes on a rack inside your house, and they'll dry while you are at work.
Re:Consequences of cheap nuclear power? (Score:2)
Comment removed (Score:4, Interesting)
too bad they stopped building them... (Score:3, Interesting)
Re:too bad they stopped building them... (Score:2, Insightful)
Re:too bad they stopped building them... (Score:5, Informative)
1) 80% of electricity in France is nuclear (Paris vacation, anyone?)
2) There is more radiation in the U.S. Congress due to its granite construction than is permitted outside a nuclear plant
3) If you take 4 cross-country airplane trips, you get more radiation than allowed at nuclear plants
4) If you live in mountains (Colorado) you also get more radiation, due to the altitude
5) Best estimates are for 325 long term general population deaths arising out of the Chernobyl radiation escape. Guess how many cancers due to oil/coal burning plants elsewhere?
6) Current nuke plant designs have a bias for automatically stopping the reaction at the slightest or even gravest out of spec situation. Imagine your car's engine designed to stop every time you rev up/speed/your dome light burns out.
Fact is, greenies have scared the public, we are currently poisoning our air with oil/coal power plants, creating thousands of new cancers every year. Thanks, tree-huggers.
What surprises me... (Score:5, Interesting)
For instance, at TMI, there was a massive chain of events going like this (I'm taking this from the Wikipedia article). If any of these steps were omitted an accident never would've happened:
1. "The plant's main feedwater pumps in the secondary non-nuclear cooling system failed at about 4:00 a.m. on March 28, 1979"
2. "This failure was due to either a mechanical or electrical failure and prevented the steam generators from removing heat."
3. "First the turbine, then the nuclear reactor automatically shut down. Immediately, the pressure in the primary system (the nuclear portion of the plant) began to increase."
4. "to prevent that pressure from becoming excessive, the pressurizer relief valve (a valve located at the top of the pressurizer) opened."
5. "The valve should have closed when the pressure decreased by a certain amount, but it did not. Signals available to the operator failed to show that the valve was still open. As a result, the stuck-open valve caused the pressure to continue to decrease in the system."
6. "Meanwhile, another problem appeared elsewhere in the plant. The emergency feedwater system (backup to main feedwater) was tested 42 hours prior to the accident. As part of the test, a valve is closed and then reopened at the end of the test. But this time, through either an administrative or human error, the valve was not reopened -- preventing the emergency feedwater system from functioning."
7. "As the system pressure in the primary system continued to decrease, voids (areas where no water is present) began to form in portions of the system other than the pressurizer."
8. "Because of these voids, the water in the system was redistributed and the pressurizer became full of water."
9. "The level indicator, which tells the operator the amount of coolant capable of heat removal, incorrectly indicated the system was full of water."
10. "Thus, the operator stopped adding water. He was unaware that, because of the stuck valve, the indicator could, and in this instance did, provide false readings."
And so on and so forth. This is terrific shit. Seeing how many stages the thing went through just makes me glad this happened somewhere other than the decomposing USSR. With better engineering of measurement tools the whole thing would never have happened.
You left this out... (Score:4, Informative)
If they had used analog dials instead of digital readouts, the operators would have seen a bunch of dials all pegged high, instead of seeing what looked like an instrument failure.
Given that data, there's chance that when steam bubbles started forming in the primary system outside of the pressurizer (your "voids"), the operators would not have shut down the primary reactor coolant pumps (the big pumps that circulate water between the core and steam generators). The operators shut down those expensive pumps because the steam bubbles caused them to start cavitating, which would eventually destroy them. If those pumps had been kept running, the core would have received some cooling, and the operators would have known that more was wrong...
Maybe if the operators had known that core temps were going through the roof they would have acted totally differently.
PS - I have no idea how the operators could have missed a stuck-open relief valve - even a steam relief valve from the top of the pressurize. When those things lift, it sounds and feels like a train going by...
Re:What surprises me... (Score:5, Insightful)
You have no idea buddy... take a look at the Presidential Report. Your above-included description lacks many other key elements that contributed to the factor. The failure that you list in (1) was most probably caused by cleaning the scrubber - the device that removes assorted crap from the incoming water into the secondary system. Unfortunately the scrubber regularly deposited large amounts of thick resin in the feedwater line. This resin is highly resiliant to chemical attack and needs to be cleaned away using a high pressure water hose. The control valve for the feedwater system works on pressurised air, and the cleaning process forced water and resin into the control system, resulting in a half open "8" (one of the valves, there's a complementary valve called a "12"). So the failure here was operational - Metropolitan Edison chose a poor method of cleaning.
There existed a secondary feedwater system, but unfortunately the operators had left the "8" of the secondary system closed (as mentioned in step 6). They didn't see the light telling them it was closed, as it was covered by a maintenance tag. If no stupid cardboard-tag based maintenancy strategy was used then they would have seen. The failure here was operator error/poor operational specification.
The operators didn't know that the PORV (pilot operated relief valve) was stuck open, and made assumptions about its behaviour. There was an emergency PORV-valve, known as a block valve. The operators didn't close this, despite the fact the drain temperature for the containment tank was over 2800 degrees farenheit, while normal operating temperature was in the range of 200. During a conference call with the senior Met. Ed. engineers they asked if this valve was closed. One of the operators said "yes", then covered the phone mouthpiece with his hands and shouted to the other engineer to close it. The failure here? Operator error and a terrible corporate culture that resulted in operators lying to senior engineers.
there's a shitload more problems with TMI, but to blindly say that this could have been solved by better engineering practice? No, you sir, are talking shit. A large number of the failings were operaional/human/organisational and outside the scope of any engineers ability to deal with.
Re:What surprises me...is needing glasses (Score:2)
Wow, I read that as "menstruation". Talk about a case of PMS.
The Difference Between TMI and Chernobyl (Score:3, Insightful)
Containment for graphite-moderated reactors to big (Score:4, Interesting)
Chernobyl was a graphite-moderated reactor, which means that the fast neutrons were slowed by bouncing off the carbon atoms.
An interesting thing about water is that it has two effects in fission reactors:
1. It acts as a moderator (bouncing neutrons off the hydrogen atoms of water molecules is one of the best ways to slow a neutron down).
2. Water also acts as a poison to the chain reaction. The hydrogen atoms do have an affinity to sucking up neutrons and turning themselves into deuterium and tritium. This effect causes the fission chain reaction to peter out.
Which effect predominates depends on the physical geometry of the core and the layout of fuel, water, control rods, graphite, whatever else is in the core.
At TMI the moderation effect of water predominated, at Chernobyl the poison effect.
This means that at Chernobyl the primary coolant acted as a poison to the chain reaction - so remove the coolant and the nuclear reactions run amok - not an explosion, but all kinds of bad stuff. And that "bad stuff" includes, IIRC, a phase transformation of the graphite at a really high temperature that releases a lot of energy.
Conversely, at TMI when the core lost its coolant fission stopped and only decay heat from the radioactive decay of fission products remained - more than an order of magnitude less than rated reactor peak power depending on power history of the reactor (i.e., if the reactor has been running at 100% power for a few weeks, decay heat production is maxed at about 7% of full power, and decays rapidly)
But the loss of coolant at Chernobyl and resultant runaway nuclear reactions caused a steam explosion of the remaining coolant in the core that severed all emergency coolant connections into the core (and kill everyone in the reactor building itself, IIRC). This steam explosion probably would not have breached any containment vessel, but the later energy release from the graphite and the fires almost certainly would have anyway.
And Chernobyl was all caused by dumbasses shutting down the reactor protective systems designed to prevent them from running the reactor in such a condition. Chernobyl had safety features to prevent operation in the range where the disaster that happened would be possible (which was actually highly dependent on power history since the radioactive fission products also have a huge effect on fission in the core [ iodine-136, IIRC]), but since the engineers had a test they just had to perform even though the reactor hadn't been shutdown for a few days like it was supposed to be, they simply shut down the system that was designed to prevent the reactor from going kaboom.
Gotta call mom (Score:5, Interesting)
In all seriousness, if anybody has any questions they'd like me to pass on I'd be more than willing to. I'll post the answers here or in a JE or somewhere.
Triv
Re:Gotta call mom (Score:2, Interesting)
Not trying to blame the operator or anything - but what level of understanding/theory did they have?
Were they aware that it was possible for the water level indicator to give incorrect readings?
Was there any "manual" way for an operator to casually check (sanity check) proper functioning if they suspected a fault, or would that have required additional personell/procedures?
I guess being in the 1970s, t
from King Size Homer (Score:4, Funny)
Burns: Homer, your bravery and quick thinking have turned a potential Chernobyl into a mere Three Mile Island. Bravo!
Toured TMI (Score:4, Interesting)
We were able to visit some aspects of the non-functioning side - the cooling towers (I have photos I took while standing inside one [uiuc.edu], and here's another [uiuc.edu]), the empty turbine room, and the control room.
Surprisingly standing around the skeletons of the non-functioning cooling towers wasn't nearly as strange as comparing the turbine rooms between the functioning and non-functioning sides of the plant.
Anyone who has seen a turbine room in any kind of large power plant knows how huge they are. The turbine room used for the functioning reactor was hot, noisy, and full of intimidatingly large equipment. The huge emptiness of the unused turbine room was just plain strange in comparison.
IMNSHO, the worst thing about the TMI accident was the lack of communication both inside and outside of the plant. We can only hope that we've learned from our mistakes.
Reminds me of a quote (Score:5, Funny)
SL-1 (Score:3, Informative)
One technician was blown to the ceiling of the containment dome and impaled on a control rod. His body remained there until it was taken down six days later. The men were so heavily exposed to radiation that their hands had to be buried separately with other radioactive waste, and their bodies were interred in lead coffins.
One of the victims was interred at Arlington National Cemetery:
SUBJECT: Internment of Radioactive Remains
TO: Superintendent
Arlington National Cemetery
Arlington 11, Virginia
1. Radioactive remains of SP4 Richard L. McKinley were interred at Arlington National Cemetery on 25 January 1961.
2. It is desired that the following remark be placed on the permanent record, DA Form 2122, Record ofInternment:
"Victim of nuclear accident. Body is contaminated with long-life radio-active isotopes. Under no circumstances will the body be moved from this location without prior approval of the Atomic Energy Commission in consultation with this headquarters."
A careful examination of the remains of the core and the vessel concluded that the control rod was manually withdrawn by about 50 centimeters (40 centimeters would have been enough to make the reactor critical), largely increasing the reactivity. The resulting power surge caused the reactor power to reach 20,000MW in about
TMI wasn't the first or only nuclear reactor accident in the US.
In spite of this 'negative publicity', I still strongly support nuclear power.
gutless crybabies (Score:4, Informative)
The russians on the other hand, their main food production area is not EPA weenie HOT, its will I die of this THIS year hot. And they keep all the reactors of the same type going because if they shut them down they'll FREEZE to death.
In the US most of our energy problems are self inflicted, political scams to run up energy sales prices, the oil companies sticking it to the consumer every time the EPA sticks it to them, calfornia sucking up all the cheap natural gas so they can have "clean" power and then the people in the northern states who relied on that for home heating now have their bills tripple or more. While those using heating oil and some cases even just electricity are now paying less while carbon fouling the air like crazy. And don't think that coal is "non-nuclear" the ash from burning that doesn't go up in the air is contains enough uranium and thorium to be a potential source of reactor fuel. http://www.ornl.gov/info/ornlreview/rev26-34/text
At least in a nuclear plant they keep the waste and fuel contained, not blasted out of a smoke stack or floating around on some barge until they can find a country to unload it in.
The energy has to come from some place. And it HAS to come from YOUR BACK YARD because the grid wasn't made to have power generated in a designated dirty state like kentucy, or tennessee and transmitted all the way to the east coast. The question is, do you want CO2 and thorium ash spewing plant in every city, or a reactor powering 12 cities and giving some neurotic mommies a panic attack 6 times a day.
As for alternate energy, solar cells take a lot of power to make, windmills take energy to machine and transport to the location, micro-turbines/water wheels require a certain type of landscape and water supply. All these are great if you live in the middle of nowhere. Solar heating/cooling is great if you can afford to have it worked into your house.
But the bulk of your power needs still come from coal and nuclear power. And nuclear power can't continue if you have to bury every ton of concrete ever touched by 12 extra neutrons in some dump. And coal burning can't go on for another hundred years or we'll run out of air. This means we have to come up with some sort of reasonable nuclear regulation, acceptable loses, etc.
Human (un)reliability... (Score:5, Insightful)
Both Chernobyl and TMI happened because the humans didn't fulfill their role in the reliability chain.
In both cases, humans misreading or misinterpreting information worked against the automatic protection systems correct safing actions.
To technocrats like us, the obvious solution is fully automatic, unmanned atomic powerplants.
Considering that we cannot even drive a car 20km by computer, I don't think we are anywhere close to ready for that sort of challenge yet.
So while nuclear energy may be ready, we're not.
(And there's also that pesky detail about the spent fuel.)
The best part about Three Mile Island (Score:4, Funny)
Comment removed (Score:4, Funny)
The nuCLEAR Truth (Score:5, Insightful)
The trush is that nuclear power is already the safest and cleanest power source in the USA - even when you include taking care of radioactive waste.
The truth is, as has been pointed out here several times, that coal powered plants in the USA (trace radiation) are more radioactive then nuclear plants.
The truth is, that 3 mile island was the ultimate example of why nuclear power in the US is so safe. Even in worse case scenarios, and with 20 simeltanious managment and design failures - nothing harmfull happened to anybody.
The truth is, the movement against nuclear power has far more to do with OPEC financing than concern for safety, liabilities, or the environment.
The truth is that 3 mile island wasn't a nuclear disaster by any measure, it was a political disaster.
The truth is that dealing with nuclear waste isn't a problem either, it's also a political problem.
The sad truth is that we could all have had clean, cheap, safe, and environmentally friendly power a long time ago. But big huge nuclear powerplants are just simply too tempting of a target
Unfortunately, the popular mob is all to often like a herd buffalos, the stampeed that saves one from a lion kills thousands as they head toward the cliff.
Oh, dear God, no. (Score:4, Informative)
Re:Oh, dear God, no. (Score:4, Informative)
So the question then becomes to make the reactor vessel, associated piping, and the building strong enough to contain radioactive particles under worst case accident scenarios.
This we can do at groundlevel. (groundlevel, meaning near the surface. The top of the uranium fuel at my power plant is 40 ft below ground level, but still above the water table. And there's a whole lot of steel and reinforced concrete between the fuel and the groundwater table)
So why not put it below ground?
1. Cost.
2. No point, as there are other ways to contain the issue.
Groundwater (Score:3, Informative)
Re:Question (Score:3, Informative)
Then, when it all cools down, groundwater will get into it and spread radiation throughout the watershed. If it didn't boil of as radioactive steam first. Think of the problems if a reactor in the upper reaches of the Missouri explodes, and radioactive water contaminates the whole Mississippi-Missouri water system. Not fun.
Re:Question (Score:2)
Nuclear Power, or Mistresses? (Score:3, Funny)
On the other hand, nuclear power stations won't give you a drunken blowjob -- whereas the Presidency is a pretty sure path to extramarital nookie.
-kgj
Re:no more power plants (Score:4, Informative)
Re:What impact? (Score:4, Insightful)
Recycle it, wind up with 90 to 95% less material and more fuel. The remaining 5 to 10% (i have heard) is about as radioactive as your car and would fit under your desk. Disposal problem solved.
And if you say that "If thats true, why don't we already do that?" take a look at the Anti-Nuclear-Anything loby that would lobby against anything with the word Nuclear in it even if it solved all our energy problems, every known disease including cancer and produced no pollution in any way, as long as it had anything to do with anything Nuclear.