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If graphite cracked/crumbled to prevent the control rods from being re-inserted, that's some scary stuff. The article ending with a request for the safety limit
by module0000 7y ago
If graphite cracked/crumbled to prevent the control rods from being re-inserted, that's some scary stuff. The article ending with a request for the safety limit for number-of-cracks to be increased was really surprising for me. The whole "risk VS reward" test comes to mind... the reward is power for 1.8 million homes, but the risk is total catastrophic destruction of the environment for (tens of) thousands of years. The odds may look good, but geez...just a huge gamble to take with other peoples homes/property/lives.
- petre 7y ago> total catastrophic destruction of the environment for (tens of) thousands of years More like 300 years (10 Cs137 and Sr99 half lives) but otherwise you're right.
- deleted 7y ago[deleted]
- mimixco 7y agoPlutonium, a byproduct of all nuclear reactors and part of their waste stream, is dangerous for 240,000 years.
- strken 7y agoHow much plutonium is likely to be released in a nuclear incident? I thought Three Mile Island and Chernobyl mostly released radioactive isotopes of iodine and a bunch of noble gasses, with cesium, plutonium, and strontium being present in smaller quantities and generally settling closer to the reactor.
- antidesitter 7y agoWhere did you get that number?
- wahern 7y agoSeems like a typo. Half-life of Pu-239 is ~24,000 years, and of Pu-242 ~374,000 years. I'm guessing Pu-239 was intended as 1) an extra "0" digit is the more likely typo, and 2) Pu-239 is (AFAIU) the principal Plutonium byproduct of typical Uranium fission reactors.
- mimixco 7y agoHalf life means that radioactivity is reduced by half, not eliminated. A single particle of plutonium is enough to cause cancer and kill a person. This is why nuclear fuel rod storage (the waste products) must be guarded for hundreds of thousands of years.
- petre 7y agoHalf life is inversely proportional to radioactivity. Hundreds of thousands of years = no worries, you only live up to 1e-3 that amount.
- dingaling 7y agoNot all reactors; fast neutron burner reactors output less Pu than they consume.
- mimixco 7y agoThose exist only on paper. I'm speaking of actual production reactors which create dangerous amounts of plutonium-laden waste that needs to be cooled, monitored, and protected from human intervention for hundreds of thousands of years -- a problem that we still have no way to solve.
- wbl 7y agoPlutonium release is far less being less mobile and it doesn't have the biological issues strontium does.
- kakwa_ 7y agoWell, it depends, if you're at 10 times the safe level, you will need far more than the half life. Most likely between 900 and 1200 years.
- petre 7y ago10 half lives = QTY/1024. Not one half life. At Chernobyl one half life has already passed.
- eecc 7y agoHow fitting in this case is the airing of the HBO Miniseries Chernobyl? The timing sometimes is just so perfect
- StavrosK 7y agoYou're probably hearing about this because Chernobyl aired. It wouldn't be newsworthy otherwise.
- new4thaccount 7y agoThere is some series on nuclear disasters going on all the time. PBS just did a big one on Fukishima last year and Command and Control has been put out again recently. Maybe it's a slight surge, but people have always been interested in these subjects. If you haven't seen either I would highly recommend. Command and Control is particularly frightening as many don't know about it.
- dTal 7y agoChernobyl is particularly relevant though due to the similarity of the potential failure modes (control rod thermal failure preventing full insertion leading to meltdown).
- jotm 7y agoI've read about the cracks around a year ago. https://www.bbc.com/news/uk-scotland-glasgow-west-43988385 https://www.bbc.com/news/uk-scotland-glasgow-west-43988385 https://www.theguardian.com/environment/2018/may/06/cracks-nuclear-reactor-threaten-uk-energy-policy-hunsterston https://www.theguardian.com/environment/2018/may/06/cracks-n...
- kortilla 7y agoWhy do you assume the failure mode here is catastrophic?
- calcifer 7y agoBecause we already know what happens when you can't insert the rods and stop the reaction.
- 08-15 7y agoHow do we know? Are you referring to the Borax experiments or the tests on EBR-II? How are they relevant to an AGR?
- DoctorOetker 7y ago"why do you assume that the failure mode of a broken condom could imply unplanned pregnancy?"
- deleted 7y ago[deleted]
- tuxxy 7y agoNo idea why you're getting downvoted... It's not like modern nuclear reactors can only fail catastrophically, much less a predictable failure case that engineers are actively monitoring to ensure the safe operation of said reactor. What's terrifying are the failure cases that the engineers aren't aware of -- the unknown unknowns -- which are probably significantly fewer than the cases they are aware of and are monitoring.
- Yizahi 7y agoWell if we set the question like this then fossil fuels are about the same - power for everyone for the small chance to kill from thousands to billions.
- mortehu 7y agoIn the case of fossil fuel, this is not an incremental risk per plant. Each fossil fuel plant gives electricity to a similar number of people, but can't individually render a subcontinent uninhabitable.
- AmericanChopper 7y agoThe WHO will tell you that air pollution from fossil fuels kills millions of people each year (multiple times more than even the most outrageous estimates of the combined death tolls of all nuclear accidents in history - even if you add Hiroshima and Nagasaki to the list). You also don’t have to look very hard to find information about how air pollution could lead to large portions of the planet being uninhabitable.
- mortehu 7y agoAgain, this is aggregate air pollution, not caused by one individual fossil fuel power plant. My whole point was this distinction. Obviously fossil fuels in aggregate cause lots of death and damage.
- manfredo 7y ago> but the risk is total catastrophic destruction of the environment for (tens of) thousands of years. This is ranging on hyperbole. Even in the case of a meltdown the result wouldn't be another Chernobyl. The latter was an unshielded reactor. Literally the soviets didn't bother putting a concrete condom on their reactors, because that would be too expensive. We've already experienced meltdowns in properly built reactors: https://en.wikipedia.org/wiki/Three_Mile_Island_accident https://en.wikipedia.org/wiki/Three_Mile_Island_accident
- jarvist 7y agoLike Chernobyl, AGR reactors do not have secondary containment: the idea was that as they are gas cooled (no water to phase change) and have enormous cores (so much more time to deal with heat build up), they are safe enough to not need it.
- manfredo 7y agoI don't know where you're getting that info. This one says that AGR reactors have 5-7 meter thick reinforced concrete walls: https://inis.iaea.org/collection/NCLCollectionStore/_Public/28/028/28028509.pdf https://inis.iaea.org/collection/NCLCollectionStore/_Public/...
- mmaurizi 7y agoThis isn't a separate containment structure surrounding the reactor, but part of the reactor itself. From your own link, page 42, section 5.8 Containment systems: > Thus, there seems to be a barrier less in AGR compared with LWR reactors. In AGR's the pressure vessel and containment is one unit, but the vessel contains the total primary circuit.The main reason for this difference is the single phase CO2 coolant used in AGR compared with the H2O coolant in LWR. CO2 cannot undergo suddenly phase change as a result of an unexpected rise in temperature or pressure, i. c. it cannot flash as water. It means that there can be no sudden discontinuity of cooling under fault conditions, and changes in flows, temperatures and pressures progress rather slow.
- 7y ago