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Science Technology

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."
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25th Anniversary Of Three Mile Island

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  • by Anonymous Coward on Sunday March 28, 2004 @09:13AM (#8695101)
    Oblinks to related wikipedia articles:

    Three Mile Island []

    List of nuclear accidents []
  • Shame (Score:5, Insightful)

    by colinramsay ( 603167 ) on Sunday March 28, 2004 @09:13AM (#8695105) Homepage
    It's a shame that incidents such as this have contributed to the overall bad image of nuclear power. There is still a lot of potential which will probably never be revealed because the public at large are scared of what could happen if something went wrong.

    The truth is that modern techniques could probably make nuclear power an extremely safe alternative.
    • Re:Shame (Score:5, Informative)

      by Anonymous Coward on Sunday March 28, 2004 @09:27AM (#8695136)
      The truth is that modern techniques could probably make nuclear power an extremely safe alternative.

      Especially pebble bed reactors [].

    • Re:Shame (Score:4, Insightful)

      by AlecC ( 512609 ) <> on Sunday March 28, 2004 @09:27AM (#8695137)
      On the point of making nuclear power stations safe, I agree with you. There are some designs around not for which the worst credible accident is really not that bad at all.

      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?
      • by Unknown Poltroon ( 31628 ) * <> on Sunday March 28, 2004 @09:41AM (#8695196)
        How DARE you suggest that we pollute the pristine magma of the earths core with your unnatural nuclear waste. It would be a crime against nature to bury radioactve material under the earths crust.

        People like you make me sick.
      • Re:Shame (Score:2, Insightful)

        by dfenstrate ( 202098 )
        I'm guessing because it would take a very, very long time to dissappear, maybe longer than it would take to turn into safe material all by itself.

        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)

          by Dun Malg ( 230075 )
          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.

          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

          • If all you saw was a "lizard" and Raymond Burr, then all you saw was a bad hatchet job. The real thing will be in a few theaters this spring and summer in the US. (Otherwise, I agree with you, Dun Malg.)

            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)

        by magarity ( 164372 ) on Sunday March 28, 2004 @02:07PM (#8696448)
        subduction zone disposal - return it to the earth's core, which is used to it. Does anybody know why this disappeared off the map?

        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 [].
      • Re:Shame (Score:3, Interesting)

        >But there is still the waste disposal problem.

        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)

      by Anonymous Coward on Sunday March 28, 2004 @09:38AM (#8695180)
      The thing which I can not fathom about the American nuclear power policy is that they are encouraged to make HUGE reactors. (Had to look this up for nuclear physics class at one point) The US Navy has an almost perfect record with identical, small reactors. I conject that the safety part of the equation has been figured out. I persistantly wonder why it's a bad thing not to just use the design from a submarine and just put 12 of them in a row, all of the same design, and man them with ex-Navy personnel.

      At this point, I'd put a dog on a treadmill generator to not have coal power though...or an ignorance-rutting politician. ;P

      --degs at 68k dot org

      • Re:Shame (Score:4, Insightful)

        by Smidge204 ( 605297 ) on Sunday March 28, 2004 @10:33AM (#8695377) Journal
        It's economics, really.

        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.
      • Re:Shame (Score:5, Informative)

        by nyseal ( 523659 ) on Sunday March 28, 2004 @12:04PM (#8695849)
        As an ex-nuclear machinist's mate aboard a US Navy sub I can tell you for a fact that the record is perfect. The 2 subs lost (Thresher & Scorpian) were not due to nuclear accidents. The original design and construction of the USS Enterprise included 9 reactors (9? whew!) in which 7 were subsequently removed. Each could power a city of about 250,000 people effectively. And by the way, most nuclear power plants ARE run by ex-Navy personnel. Most of them hire no one but ex-Navy.
        • Re:Shame (Score:3, Informative)

          by Anonymous Coward

          Not to pick but as a former MM on the Enterprise she was originally designed, and currently contains 8 reactors []. All Nimitz class carriers contain 2 reactors [].

          You are correct that each reactor could power a small city. The prototype I attended in Idaho at the INEL (now INEEL) [] 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)

          by Vellmont ( 569020 )
          I wouldn't say exactly perfect, unless you don't have a problem with dumping out radioactive waste.
          There's 7 incidents we know about. Given the secrecy of the military who knows if there's more that we don't.


          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
      • Re:Shame (Score:4, Interesting)

        by Ironsides ( 739422 ) on Sunday March 28, 2004 @01:22PM (#8696207) Homepage Journal
        Actually, most people running nuclear reactors ARE ex-Navy personel. After they serve there years in the Navy, they are EXTREMELY employable at the power plants due to their level of training and experience. And these guys probably get at least $100k per year at a reactor plant, more that double what they get in the Navy when they retire.
    • Re:Shame (Score:4, Interesting)

      by coastwalker ( 307620 ) <.acoastwalker. .at.> on Sunday March 28, 2004 @09:39AM (#8695186) Homepage
      There has to be a continious re-evaluation of all potential sources of power whilst our fossil fuel reserves are being depleted. It is perhaps better that we discover the potentials and the pitfalls of nuclear power before the situation arises where there is no choice but to use nuclear power. We do now at least have the knowledge to advise the growing Chinese economy on the safest way to utilise it for example should they find the need for power outstrips the availability of fossil fuel.

      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:Shame (Score:5, Insightful)

      by Zeinfeld ( 263942 ) on Sunday March 28, 2004 @09:45AM (#8695208) Homepage
      It's a shame that incidents such as this have contributed to the overall bad image of nuclear power.

      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)

        by john.r.strohm ( 586791 ) on Sunday March 28, 2004 @10:02AM (#8695265)
        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.

        The statement "(t)he coolant doubles as the moderator" is also true of American light-water designs.
      • CANDU system info (Score:3, Informative)

        by Faeton ( 522316 )
        As someone pointed out, light water reactors use light water to moderate. CANDU uses heavy water (deuterium) to moderate. CANDU is only "safer" because it uses natural uranium, rather than enriched (though there has been a push for some slightly enriched CANDU reactors). Natural uranium contains less energy per gram than enriched (due to lower concentrations of U235, which is more fissile than U238).

        So, because there's less energy per gram, CANDU system have online fueling, which means that the reactor

    • Re:Shame (Score:5, Interesting)

      by john.r.strohm ( 586791 ) on Sunday March 28, 2004 @09:48AM (#8695214)
      The truth is that modern techniques could probably make nuclear power an extremely safe alternative.

      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 oid-coefficient-of-reactivity.html "Void coefficient of reactivity: A rate of change in the reactivity of a water reactor system resulting from a formation of steam bubbles as the power level and temperature increase."

      From 748 "The 'voids' refer to pockets of steam forming in the reactor core, and a reactor is said to have a positive void coefficient if an increase in voids leads to an increase in reactor power. A reactor with a negative void coefficient is one which will see a decrease in reactor power as pockets of steam increase."

      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.)
      • you make a fine case for going with renewable energy sources like wind turbines, solar power, wave energy and the like. I can only suppport that.

        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
        • The problem with "renewable" sources is that they are all inherently unsuitable for baseline supply.

          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)

        by Artifakt ( 700173 )
        Carbon 14 is something that needs to be taken more seriously than it generally is. C 14 decays to nitrogen, so its stable decay endpoint is chemically different. How much chance is there of a single C 14 atom's cauasing a mutation if it decays inside a living creature? The answer is frequently treated as not a lot, compared to the stuff we've been calling really dangerous, like Plutonium, right?
        Wrong. Since the DNA molecule has a carbon based backbone, the chance of a C 14 decay causing a mutation is 10
  • Stop and pause (Score:3, Insightful)

    by blankmange ( 571591 ) on Sunday March 28, 2004 @09:14AM (#8695107)
    With the posting of the Chernobyl [] story yesterday, this should make some of us pause and think about what could have been...
    • Re:Stop and pause (Score:5, Informative)

      by jeffy124 ( 453342 ) on Sunday March 28, 2004 @09:50AM (#8695220) Homepage Journal
      Chernobyl was a completely different animal to TMI. Operators at the plant brought that disaster entirely upon themselves. They were doing an "experiment" to see what the minimal resources were to keep the plant operating, overriding automatic shutoffs and other alarms in the process. Eventually, they overrode one alarm too many.

      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.
      • Yes, but without that direct human action in the form of interference with the automatic systems, TMI would still have been nothing more than a valve repair for the maintainance people. The automatics were working just fine till some shithead turned it off.

        Cheers, Gene
        • Re:Stop and pause (Score:5, Informative)

          by mfarver ( 43681 ) * on Sunday March 28, 2004 @11:33AM (#8695666) Journal
          The parent is correct.. if worded badly.

          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)

      by djh101010 ( 656795 ) on Sunday March 28, 2004 @10:23AM (#8695324) Homepage Journal
      With the posting of the Chernobyl story yesterday, this should make some of us pause and think about what could have been...

      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:3, Interesting)

      by phillymjs ( 234426 )
      ...this should make some of us pause and think about what could have been...

      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)

    by PacoTaco ( 577292 ) on Sunday March 28, 2004 @09:21AM (#8695119)
    Fusion power [] is the way to go. It's potentially much safer [] and can generate a ton of electricity without air pollution.
  • by AtariAmarok ( 451306 ) on Sunday March 28, 2004 @09:33AM (#8695164)
    "Oh little isle, of 3 Mile. How still you make us die.
    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"
    • This was probably written by some pansy-ass literature major with too much time on her hands, no technical knowledge, and an activist bent. The kind of idiot who dresses up in pink and does interpretive dance to try to influence matters she hasn't taken the time to really understand.

      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
  • by wombatmobile ( 623057 ) on Sunday March 28, 2004 @09:35AM (#8695171)

    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?

    • by joelsanda ( 619660 ) on Sunday March 28, 2004 @09:41AM (#8695195) Homepage
      Interesting - Austrailia must not have HOAs (Home Owners Associations) similar to those in the U.S.? My HOA policy is fairly forgiving on that piece: I can use a clothesline but it has to be a 'temporary' one that is taken down after it's use. Maybe I'll run a long extension cord from our laundry on the second floor of our house and put my dryer in the yard. Nothing in the HOA rules state running appliances can't be used in the yard! That way I can dry my clothes outside in the sunshine and still thumb my nose at the Kyoto Protocol. American Green ;-)
      • How come that in _free_ USA you are not allowed to do what you want on your own property? Sounds a lot like USSR to me...
      • 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)

      Well you could dry them outside, if you like to have your pockets full of dust when you bring them in.
    • by Anonymous Coward
      Arizona actually uses very little of the power generated by the Palo Verde nuclear power plant. We sell it to California to power their espresso machines. :)

      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.

  • by DangerSteel ( 749051 ) on Sunday March 28, 2004 @09:36AM (#8695176)
    I remember reading about nuclear power plants that were in the middle of construction when TMI happened. And then the projects went dead. Uneducated people were scared to let the plants be continued, ( in my best Hank Hill voice ) and those damn hippies needed to get jobs, and that's partly why we are way behind in providing power today. Witness events like the brownouts in California and the big power outage last year in the northeast U.S.
    • One fact I picked up over the years is since TMI, no one's ever applied for a new permit from the NRC
    • by XavierItzmann ( 687234 ) on Sunday March 28, 2004 @10:20AM (#8695314)
      People do not realize that:

      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)

    by James A. M. Joyce ( 764379 ) on Sunday March 28, 2004 @09:37AM (#8695178) Journal seeing how the fuck these accidents actually happen. Both Chernobyl and TMI seem to be based on a ridiculous chain of events fuelled by unfortunate coincidence, fallible mensuration equipment and human idiocy.

    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)

      by Anonymous Coward on Sunday March 28, 2004 @09:53AM (#8695231)
      TMI used digital temperature readings for core temperatures. They started going up and up, but when they went above the highest temperature the instruments were designed to read, they started recording "???" instead of a number.

      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...

    • by Anonymous Coward on Sunday March 28, 2004 @10:03AM (#8695267)
      With better engineering of measurement tools the whole thing would never have happened.
      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.
    • From the article : Both Chernobyl and TMI seem to be based on a ridiculous chain of events fuelled by unfortunate coincidence, fallible mensuration equipment and human idiocy.

      Wow, I read that as "menstruation". Talk about a case of PMS.

    • You have a long chain of horrible coincidences which should have been stopped earlier. At TMI, it was finally stopped. What stopped it? The last-ditch measure that every sanely-designed reactor has; the giant, meters-thick steel-reinforced concrete containment dome. This is the reason why the explosion at TMI never went anywhere. The bright sparks behind the design of Chernobyl (and most other Soviet reactors) decided that their reactor didn't need such a safety measure. If Chernobyl had had a decent contai
      • by Anonymous Coward on Sunday March 28, 2004 @11:28AM (#8695644)
        TMI was a pressurized-water reactor. These are also water-moderated. I.e., fast neutrons from fission are slowed to thermal speeds so they can cause more fission reactions by the water in the core.

        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)

    by Triv ( 181010 ) on Sunday March 28, 2004 @09:38AM (#8695182) Journal
    My mother used to work for General Public Utilities (the company that owned TMI) and was at the plant during the accident - it's probably the cause of my glowing personality. (rimshot).

    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.


    • Re:Gotta call mom (Score:2, Interesting)

      by csirac ( 574795 )
      I've never really studied this incident, so here are my questions probably already answered out there..

      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
  • by Anonymous Coward on Sunday March 28, 2004 @09:54AM (#8695234)
    From 3F05: []

    Burns: Homer, your bravery and quick thinking have turned a potential Chernobyl into a mere Three Mile Island. Bravo!
  • Toured TMI (Score:4, Interesting)

    by arachnia ( 104881 ) on Sunday March 28, 2004 @10:07AM (#8695281)
    I used to work in the radiation safety field and went on a technical tour of TMI just before the change in owners (current owner is AmerGen).

    We were able to visit some aspects of the non-functioning side - the cooling towers (I have photos I took while standing inside one [], and here's another []), 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.
  • by ( 547663 ) <haas AT itu DOT dk> on Sunday March 28, 2004 @10:20AM (#8695316) Homepage
    Reminds me of a quote by Terry Pratchett []:

    I once absend-mindedly ordered Three Mile Island dressing in a restaurant and, with great presence of mind, they brought Thousand Island Dressing and a bottle of chili sauce.
  • SL-1 (Score:3, Informative)

    by meshmar ( 11818 ) on Sunday March 28, 2004 @11:07AM (#8695550) Homepage
    Many people are unaware that on January 3, 1961, SL-1, a small (about 3 MW) nuclear reactor was destroyed due to a "reactor explosion" at the National Reactor Testing Station in Idaho Falls, Idaho, killed one navy technician and two army technicians, and released radioactivity "largely confined" to the reactor building.

    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 .01 seconds, causing the plate-type fuel to melt. The molten fuel interacted with the water in the vessel, producing an explosive formation of steam that caused the water above the core to rise with such force that when it hit the lid of the pressure vessel, the vessel itself rose 3 meters in the air before dropping back down.

    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)

    by PsibrII ( 671768 ) on Sunday March 28, 2004 @12:26PM (#8695949) Journal
    After rocky flats, the detroit reactor neer explosion, hanfords non stop spew of radiation and of course after the nation had been glowing with nuke test fallout for 30 years, THEN they decide to wimp out because a reactors failsafes actually began working to the point where there was little radiation leakage ? WTF ?

    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. colmain.html

    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.
  • by phkamp ( 524380 ) on Sunday March 28, 2004 @12:43PM (#8696025) Homepage
    It has long since been recorded as a fact that any system relying on human reliability is unreliable.

    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.)
  • by flimflam ( 21332 ) on Sunday March 28, 2004 @12:52PM (#8696069) Homepage
    was when Jimmy Carter went there to say that nothing was wrong and then came out ten feet tall and glowing. That was classic.

  • by fmaxwell ( 249001 ) on Sunday March 28, 2004 @01:36PM (#8696273) Homepage Journal
    How long will it be before we get a photo album of the area around Three Mile Island put together by some gum-chewing Jersey girl riding around on a moped? Somehow it just won't be the same...
  • The nuCLEAR Truth (Score:5, Insightful)

    by argoff ( 142580 ) on Sunday March 28, 2004 @02:03PM (#8696428)

    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 ..... for politicians and regulation that is.

    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.

Who goeth a-borrowing goeth a-sorrowing. -- Thomas Tusser