I assume you are talking about a Pebble Bed reactor that is self regulating as the temperature of the fissionable materials increase. I forget the details, but at higher temperatures, I thought there was a decrease in neutron emissions or the speed of the neutrons.
What does that have to do with anything? I’m sure you’ve read numerous articles in Popular Science about it. But you just don’t seem to be able reason properly. Do you have any proof that a Pebble Bed reactor is safe if not constructed and maintained properly? Also, I may be ‘misrememberating’ here but these reactors do have an inherent danger of catching fire. That’s what happened to other safe reactor designs. Fire can carry neutron emitting material out into the atmosphere.
I also did not say I had a geothermal generator, or that they were currently practical. Maybe its difficult for you to understand, but they are not radioactive. You can’t use a geothermal generator or well to make a dirty bomb either. I’m suggesting that research into geothermal energy would pay off better than nuclear, short term, and long term.
Yeah, there’s this drink they make like that. I forget the ingredients, but as I recall you don’t remember anything that happens for about 72 hours, but there’s no headache when you come to.
I have a B.S. in Chemical Engineering, an M.S. in Environmental Engineering, graduated from Naval Nuclear Power School, and was qualified to supervise the operation of two different naval nuclear power plants. (I also taught college-level chemistry and physics for 7 years, but I’m an engineer, not a chemist or physicist. :))
The U.S. has never built a reactor like the one at Chernobyl which was inherently unstable. The Chernobyl design had a “positive temperature coefficient of reactivity,” which meant that as the reactor heated up, the rate of the nuclear reaction increased. This could lead to a runaway event, which is what happened when the operators intentionally disabled all of the the safety systems for an ill thought-out test.
The pressurized-water reactor designs that I am familiar with have a negative temperature coefficient of reactivity, so that as the coolant temperature increases, it tends to reduce the rate of the nuclear reaction, resulting in a feedback loop that inherently keeps the reactor under control, even with no operator input. Also, U.S. designs use the coolant as a moderator necessary to keep the reaction going, so that if the coolant all leaks out, the reaction automatically stops.
You can get accidents like what happened at TMI due to residual decay heat. This can be enough to melt the core, but you cannot get a runaway reaction like what happened at Chernobyl, and no reactor can be made to explode like an atomic bomb.
The U.S. Navy has never had a reactor accident, and it has operated hundreds of nuclear reactors. Two submarines with nuclear reactors have sunk, but the problems that resulted in the sinkings did not originate with the reactors. These reactors automatically shut themselves down, and tests have not indicated any increase in background radioactivity in the vicinity of the wrecks.
I wasn’t questioning your credentials. Just the credentials of some other guy who obviously didn’t have any. I’m paying attention to your remarks. I understand that reactors can be designed so that they won’t catch fire, or explode. And the Navy has shown it is possible to have a much better safety record than the rest of the nuclear industry. One reason, I suppose, is that the Navy has much more experience than other producers and designers of reactors, and has been less affected by influences that have lead to problems. But people often overestimate the output of nuclear power plants and underestimate their costs. Replacing convential power plants with nuclear in the current environment would be very expensive and fraught with hazards. I know that the Navy takes very seriously the idea that submariners will have to work in close proximity to reactors for long periods of time. The people who design, build, and maintain commercial reactors don’t seem to show the same level of concern, based on their record.
I don’t want this to sound like a slam, but you mention reactors that don’t overheat if the coolant leaks out. Wouldn’t you be a little upset if the coolant leaked into your water supply? I acknowledge this is an actual problem with geothermal wells too. In order to have enough geothermal generators to replace current power plants may require wells to be drilled through aquifers that could be polluted by the drilling process, or a PCB leak from a generation system.
So I don’t have some kind of anti-nuke philosophy, I just think there are safer alternatives to pursue as well, and ideally the choices wouldn’t be made based on anybody’s technology preference.
I don’t have an anti-anything philosophy either, nor do I have any sorts of physics credentials, but I am not aware of any poor safety record on behalf of the nuclear energy industry. Can we please get some cites as to what you are talking about? Show us a track record that does not entirely consist of Chernobyl and Three Mile Island?
I agree that there are safer alternatives, at least for people. Things like wind and solar probably only contribute habitat destruction, pollution and the occasional bird-strike as the their negative consequences. However, I don’t think you can seriously consider anything like geothermal, coal, natural gas, etc. as safer alternatives to fission. Cheaper and more politically correct – maybe, but safer?
That is just some of the cases. The list could get much longer if you include failures that did not result in harm to the public, but could have in different circumstances. You can also research Indian Point in New York to find a long list of regulatory violations, construction problems, security issues, economic loss, waste disposal problems, etc.. Also look into where the fuel for nuclear reactors comes from, and the problems that have occurred.
I stated way back in the thread that I didn’t think geothermal was being pursued because of economics. It probably isn’t cheaper. Solar and wind are great if you only need electricity in the day, or when it’s windy. Coal isn’t safe for the coal miners. There are drawbacks to every method we know of. That’s why we continue to use the known unsafe sources of energy we have, instead of rapidly switching to a different one. ‘The devil you know…’
I am familiar with that list. I am just not seeing what you’re seeing. To me that looks like a stellar safety record, especially if you include mining. Mining uranium is not done nearly safely enough, and too many people die and get exposed to radon and radioactive dust (unfortunately I can’t seem to find statistics at the moment).
However, considering coal for a moment, there are more people killed by coal mining every year in China than even the most liberal estimates for total directly and indirectly caused deaths in Chernobyl.
Don’t get me wrong, Chernobyl was bad – and believe me that I’m not understating the dangers of radiation. Other people’s incompetence in dealing with radiological materials most likely caused my fathers death. Even then, I would rather we have a Chernobyl every 5 years than continue what we’re doing to the planet and ourselves with fossil fuels.
robby and Grey cited the Navy, which has a stellar record. If everybody else did, that page would be blank. I don’t see what the argument is about. Do you contend the worst case problems with nuclear power is less harmful than alternatives? Or do worst case problems never occur. And I don’t counter nuclear with coal, so what do coal mining deaths in China have to do with it?
[sarcasm]
Wait, now I understand, you think China should replace coal burning plants with nuclear plants. Why didn’t you say so in the first place? China should copy some of our nuclear power plant designs and make lots of knock off versions to sell around the world.
[/sarcasm]
Now lets get realistic. Show me the evidence that nuclear power would be as economical as the alternatives. I’d take nuclear energy if it were safer than the others, and cost more. But the rest of the world works on the basis of what costs less. That’s why we are still polluting the air and the water and the land with coal, oil, and gas.
I disagree that nuclear power is any more fraught with hazards than other large-scale conventionally-powered plants. With respect to accidents outside the nuclear power industry, we’ve had a natural gas power plant explosion here in Connecticut in February (5 deaths, 27 injured), a coal-mining disaster in West Virginia in April (29 deaths), and the recent Deepwater Horizon blowout/explosion/oil spill (11 deaths, continuing environmental harm). A major disaster for each of the three primary fossil fuels (natural gas, coal, and oil)–and that’s just in the last four months. For comparison, the worst nuclear accident in U.S. history (TMI back in 1979) had exactly zero deaths, and the poorly designed, incompetently operated Chernobyl nuclear power plant had fewer than 50 deaths directly attributable to the 1986 accident. (While some reports estimate there may be several thousand additional cancer deaths in the region around the Chernobyl disaster, a true comparison to fossil fuel plants would also have to take into account the deaths attributed to fossil fuel plant emissions, including asthma deaths, etc.)
I’m not as familiar with the civilian nuclear power industry, but I have friends who work in that industry, and I actually came very close to working at a civilian nuclear power plant.
Anyway, from what I’ve heard, the civilian nuclear industry is quite stringently regulated at both the state and federal level. The operators are frequently tested and the plant is frequently inspected, just like in the U.S. Navy nuclear power field.
The coolant is just highly purfied water. Admiral Rickover (founder of the nuclear Navy) famously drank a glass of reactor coolant (sampled from an operating reactor) before a congressional hearing. I still wouldn’t want reactor coolant leaking into the environment, because it could have some activated particles in it (though these are continuously removed by an ion exchanger), but that is the purpose of the reactor containment building–to keep anything from escaping the plant in the event of a leak or spill. (A reactor containment building is required for all U.S. reactors and is something else that the Chernobyl plant lacked.)
I think you are correct here. My phrase implied that nuclear power plants were more dangerous than conventional power plants. Based on the measureable evidence, including accidents at nuclear plants, nuclear power plants are less dangerous. There is a death rate attributed to TMI based on statistics that indicate a certain (small) number of people died as a result of increased exposure to radioactivity. But nuclear still wins with those numbers included. The point I wanted to make was that there could be safer means than nuclear. I believe many people overestimate the danger of nuclear simply out of fear of something they don’t understand. You know, the ‘Godzilla’ problem.
I don’t intend to smear people in the nuclear industry at all. I think many of them are very frustrated themselves in being prevented from doing a better job. But the civilian nuclear industry is subject to the whims of beaurocracy, politics, and economic conditions. And while the regulations may be stringent, they’re not always followed or enforced. In the civilian world, there isn’t much responsibility taking. Some of the problems are nobody’s fault. Construction and equipment failures sometimes happen even when all regulations are followed and enforced. It was a while ago, but I remember a report of multiple cases of composite pipes bursting even though they exceeded the engineering requirements, which were correct. But the means of testing composite pipes did not produce results as reliable as the methods used on metal pipes. The safety factor had to be multiplied and the pipes re-engineered to solve the problem.
You probably have access to the data, so can you find out how safety standards compare between civilian and Navy operations?
What if there is a crack in the containment building, and the ion exchanger wasn’t working? I’m pointing out the worst case situations, where nuclear tends to lose. Back in March, if you pointed out the worst case scenario for deep water oil drilling, you would have heard snorts from a lot of people.
All I’ve said from the start of this discussion is that you can’t trust people to do the right thing all of the time, sometimes the worst case happens, and there may be alternative, less dangerous means of generating power. It’s really difficult to consider all of the factors involved and point to any means of power generation as being the best. But I think we should closely examine all of the means, and all of the factors, before making decisions.
I think ‘ed malin’ is suggesting that ‘idiots’ building a pebble bed reactor might accidentally replace the plans with the Chernobyl plans and build one of those instead, so even if your design was inherently safe, there can still be accidents.
How unlikely is it that someone will try to save money by using a new less expensive material in the Pebble Bed without conducting all the necessary work to determine it’s safety. Too unlikely I suppose.
How unlikely is it that a contractor will use substandard materials in the containment structue? Now I’m not playing fairly because I know that already happened.
How unlikely is it that someone will steal fissionable material? Hmm, where did Isreal get their fissionable material in the '60’s?
Alright, now I’m being really unfair. Let’s consider a more serious question. How likely is that someone would drill a hole in the Gulf of Mexico and release thousands of gallons of oil without having a plan to deal with that result?
Still unfair maybe. How about if I turn it around. What if drilling a geothermal well we hit a vein of heavy elements in the vicinity of a major aquifer? Should we just assume that won’t happen before we start drilling?
The only alternative to taking risks for our energy, is to stop using energy and become hunter-gatherers, again. Since the whole world depends on the current supply just for basic needs, that would entail the immediate removal of >90% of the human population. Personally, I’ll take the risks of the energy sources over the risk of being one of the losers of the lottery that decides which 90% will die.
If you are talking about me…well I HAVE a physics degree (and nuclear graduate level work)…have had a SECRET level clearance…have worked with the military on shit that could KILL people and cost millions of dollars in damage if done wrong…done military engineering RESEARCH…and been around atoms being split and handled radioactive material…and some other cool shit.
Take that and shove it up your geothermal borehole.
PS, only a retard actually needs credentials to believe or understand what someone else is talking about.
Regarding Chernobyl-I understand that the reactor indeed, had a region of instability…but the main cause of the disaster was that ALL of the emergency safety systems had been turned off (because a test was being conducted). Other than that, RMBK design was pretty conservative, and the graphite core had a huge safety margin (in terms of overheating).
The really sad thing was that had the test been conducted during a daytime shift, the accident most likley would not have occurred, because the experts were on hand.
Still, as accidents go, Chernobyl was pretty bad.
