| General > General Technical Chat |
| something is leaking in europe |
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| jmelson:
--- Quote from: jogri on June 29, 2020, 09:53:27 am ----In order to get such a leak in a normal power plant you have to have a leak in both the fuel cell AND the primary cooling loop, and you normally have detectors to detect if a fuel cell is leaking into the water-> rather unlikely that someone didn't detect the leak AND someone accidentally vented the primary cooling system. --- End quote --- True for pressurized water reactors (PWR), there's a primary cooling loop under enough pressure to not boil, and a secondary loop that boils to provide steam for the turbine. But, there are a fair number of boiling water reactors (BWR) that generate steam in the reactor pressure vessel and pipe this straight to the turbine. The turbine shafts exit from the condenser side of the turbine, where the condenser provides a pretty strong vacuum. That causes air to be sucked in at the shaft seals. So, they have vacuum pumps that remove the air, to keep the condenser working properly. Unfortunately, any radionuclides that leak into the cooling loop end up going through the vacuum pumps. Remember the Fukushima plants had those tall "smokestacks" painted with red/white stripes? Those were to vent off the gas from the turbines, and they had a steady stream of nuclides in them under normal operation. They do water treatment on PWRs that removes the gases and nuclides, but in that case they can capture them in tanks and let them decay before release. Jon |
| jogri:
--- Quote from: jmelson on June 30, 2020, 01:12:10 am ---True for pressurized water reactors (PWR), there's a primary cooling loop under enough pressure to not boil, and a secondary loop that boils to provide steam for the turbine. But, there are a fair number of boiling water reactors (BWR) that generate steam in the reactor pressure vessel and pipe this straight to the turbine. The turbine shafts exit from the condenser side of the turbine, where the condenser provides a pretty strong vacuum. That causes air to be sucked in at the shaft seals. So, they have vacuum pumps that remove the air, to keep the condenser working properly. Unfortunately, any radionuclides that leak into the cooling loop end up going through the vacuum pumps. Remember the Fukushima plants had those tall "smokestacks" painted with red/white stripes? Those were to vent off the gas from the turbines, and they had a steady stream of nuclides in them under normal operation. They do water treatment on PWRs that removes the gases and nuclides, but in that case they can capture them in tanks and let them decay before release. Jon --- End quote --- You still need two separate failures before isotopes from nuclear fission get released into the atmosphere: -one of the fuel cells has to rupture/get a tear in order to get those isotopes into the cooling loop -the containment of the cooling loop has to fail to get them into the atmosphere Yeah, could be that one of the RBMKs in Leningrad has had a failure (this somehow sounds familiar…). If i remember correctly those designs didn't employ a second containment around the core, so they could have had a ruptured fuel cell, had to remove it from the core and it vented some gas when it was out of the reactor->not everything went through the filters. Makes you wonder how on earth they planned to safely remove broken fuel rods from this reactor design... (Edit: that still wouldn't explain the clearly airborne caesium: Those reactors use light water as a coolant, the caesium would have reacted with it to form highly soluble caesium hydroxide->perfectly bound in the water of the cooling loop. So we can conclude that the source of this radiation spike was probably NOT sitting inside a water pool (water would have also captured dust too).) The isotope distribution (Cs-134 vs 137) could give a hint of how old the damaged fuel cell was (extremely old would point to subs, newer fuel to a power plant), but i'm not sure if they are going to release that data to the general public. And even then, you'd need data at which point in the fuel cycle each isotope gets created, and i'm sure that such data can't be found on Wikipedia. |
| David Hess:
--- Quote from: edy on June 29, 2020, 06:27:16 pm ---And then there are tons of these Civil Defence Geiger Counter kits. I'm not sure what the different components are. I see a "charging box" and some long cylindrical tubes. Can anyone explain a bit about whether these are any use for the type of radiation leaks we are seeing or is this for another purpose: --- End quote --- Most of the Civil Defense instruments using ionization chambers which are much more useful for detecting immediate hazards where a Geiger counter would have saturated resulting in a measured level which could be orders of magnitude low. On the other hand, a Geiger counter is exactly what is needed to test air samples like coppercone2 mentioned. With some care, you could check your basement for radon with one. --- Quote from: amyk on June 30, 2020, 12:23:38 am ---I've read that the civil defence ones are extremely low sensitivity, to the point that if the needle moves at all, you're already in big trouble. --- End quote --- But you would be in even worse trouble with a Geiger counter which unknown to you is saturated producing an erroneously low measurement. Remember at the start of Chernobyl where the radiation reading was "only" 3.5 rems per hour? In a similar incident in the US at Stationary Low-Power Reactor Number One, when emergency personnel showed up with ionization meters, they backed off because they got a true reading of the incredible radiation hazard which was present. --- Quote from: Nusa on June 29, 2020, 07:00:13 pm ---Chernobyl is in Ukraine near the Belarus border. Not in Russia at all. All of those, and quite a few others, were part of the USSR, which broke up about 5 years after the accident. --- End quote --- I was keeping things simple. Chernobyl was controlled by and the responsibility of the Soviets. The Russians now saying that nothing is wrong are the descendants, in the continuity and political sense, as the Soviets who brought us Chernobyl. Has Ukraine said anything about it? I am amazed China has not had a similar accident but they have managed to kill more people with failing dams. |
| Nusa:
--- Quote from: blueskull on June 30, 2020, 09:47:18 am ---Some news links? --- End quote --- He's probably referring to this: https://en.wikipedia.org/wiki/1975_Banqiao_Dam_failure. Many of the details were classified by China until 2005, but it's now clear it was a disaster arguably comparable to Chernobyl. It's probably before your time, and the government has changed since then. But one can say the same thing about Chernobyl. |
| Buriedcode:
--- Quote from: Nusa on June 30, 2020, 01:36:56 pm --- --- Quote from: blueskull on June 30, 2020, 09:47:18 am ---Some news links? --- End quote --- He's probably referring to this: https://en.wikipedia.org/wiki/1975_Banqiao_Dam_failure. Many of the details were classified by China until 2005, but it's now clear it was a disaster arguably comparable to Chernobyl. It's probably before your time, and the government has changed since then. But one can say the same thing about Chernobyl. --- End quote --- Yeah the death toll on that link is "85,600 to 240,000". Chernobyl was "projected" at 4000 (actual reported, 90). Or are you comparing the two in terms of land area affected? |
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