# Japan's nuclear power plants **URL:** \ **Category:** Factual Questions\ **Created:** [March 12, 2011, 5:49am UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382 "2011-03-12T05:49:04Z")\ **Posts on this page:** 20\ **Page:** 5
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [March 15, 2011, 3:38pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/81 "2011-03-15T15:38:40Z")
The pressure within the core requires that whatever cooling water (distilled or from the sea) they are going to use be inserted into it at a higher pressure, right? I don’t know if a “manual” system (engineers on a treadmill?) can deal with trying to inject water (according to the article linked by **Eleusis** , in post 73, above) against a thousand psi (which, if I read that correctly, is the operating pressure under normal conditions). You may need high powered pumps for that… ---
**Author:** ![Gray\_Ghost](https://avatars.discourse-cdn.com/v4/letter/g/c0e974/32.png) [@Gray\_Ghost](https://boards.straightdope.com/u/Gray_Ghost)\ **Post date:** [March 15, 2011, 3:45pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/82 "2011-03-15T15:45:47Z")
Perhaps a bit rah-rah, but you may find the [linked article from an MIT NukEng](http://tech.mit.edu/V131/N13/yost.html)interesting. AFAICT, he’s only addressing hazards from a reactor loss of coolant accident, not any potential hazards from the SFP. I also hasten to add that, while the linked opinion article is from a claimed Nuclear Engineer, I doubt it reflects the views of MIT or their Nuclear Engineering department. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [March 15, 2011, 3:53pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/83 "2011-03-15T15:53:05Z")
> [@Gray\_Ghost](#): > > I hope somebody screwed up the translation and meant microSievert instead. The source of that measurement had better be somewhere within the reactor building. Or standing right next to the reactor vessel as they were actively venting activated steam. No, the news articles I’ve seen are very clear on this point, the level jumped from microSievert range to hundreds of **milli** Sievert/hr range. Latest news I saw says they’re going to “allow” workers at the plant to be exposed to 250 mSv, up from the normal limit of 100 mSv, which allows them to work at the plant for just over 30 minutes rather than 15. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [March 15, 2011, 4:02pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/84 "2011-03-15T16:02:19Z")
seeing news that only 50 or 70 workers are left at the plant due to high radiation levels. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [March 15, 2011, 11:01pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/85 "2011-03-15T23:01:38Z")
So do I understand correctly that the “spent” fuel rods still generate enough heat to melt down by themselves unless immersed in water? ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [March 16, 2011, 1:41am UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/86 "2011-03-16T01:41:33Z")
> [@Gray\_Ghost](#): > > Another unsettling thing from **Sitnam** ’s linked NY Times article. > > Now, they didn’t say where they took the measurement, but 400 mSv/hr is a really big f\*\*\*ing deal. I hope somebody screwed up the translation and meant microSievert instead. The source of that measurement had better be somewhere within the reactor building. Or standing right next to the reactor vessel as they were actively venting activated steam. > > Not being in the industry, and raised on too many Cold War dramas, I still think in terms of REM. 400 mSV is equal to 40 Rem. 40 Rem/hr is dangerous to life. It won’t instantly kill you, but you’d really want to be somewhere else, fast. The article mentions that 7 minutes exposure to that intensity will give you the max annual exposure for a U.S. nuclear plant worker. 75 minutes gives you acute radiation sickness. An 8 hour workday spent in that field stands a pretty good chance of putting you in the ground. Again, I don’t remember reading anecdotes about that kind of radiation exposure for TMI. I thought the same thing when I read the article this morning. I’m also used to thinking in terms of rem, so I did the same conversion and also came up with 40 Rem/hr, and thought, “Holy shit!” :eek: When I was in the Navy, we were limited to just one-tenth the maximum allowable whole-body dose of the federal limit for radiation workers, so we would reach our maximum allowable **annual** dose (500 mrem) at that rate in just 45 seconds. (We were also limited to a maximum quarterly whole body dose of 300 mrem.) ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [March 16, 2011, 1:51am UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/87 "2011-03-16T01:51:45Z")
> [@scr4](#): > > So do I understand correctly that the “spent” fuel rods still generate enough heat to melt down by themselves unless immersed in water? Perhaps not melt, but they can certainly heat up to the point that the fuel cladding catches fire (releasing radioactive waste), depending on how long it’s been since the fuel rods were removed from the core. Ultimately, spent fuel rods will cool enough to be removed from the pool and be reprocessed to obtain usable fuel, or be processed as high level nuclear waste for disposal. It takes a few months before this is possible, though. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [March 16, 2011, 5:18am UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/88 "2011-03-16T05:18:32Z")
> [@robby](#): > > Perhaps not melt, but they can certainly heat up to the point that the fuel cladding catches fire (releasing radioactive waste), depending on how long it’s been since the fuel rods were removed from the core. In theory that’s true. Not so sure in practice. I referenced this study yesterday: [http://www.sar-net.org/upload/s2-6.pdf](http://www.sar-net.org/upload/s2-6.pdf) Zirconium fuel rod cladding was electrically heated to up to 1500 deg C and air or steam blown through to see what happens. It slowly oxidised but didn’t start a self-sustaining fire or anything like it. I think zirconium needs to be more finely divided to burn. For this reason I’m a little suspicious of reports that the reactor 4 fire was a burning zirconium fuel pool fire. I’ve read a couple of reports attributing it to burning lubrication oil. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [March 16, 2011, 12:14pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/89 "2011-03-16T12:14:22Z")
Greg Palast on Emergency Coling Systems: > [@](#): > > Last night I heard CNN reporters repeat the official line that the tsunami disabled the pumps needed to cool the reactors, implying that water unexpectedly got into the diesel generators that run the pumps. > > These safety back-up systems are the ‘EDGs’ in nuke-speak: Emergency Diesel Generators. That they didn’t work in an emergency is like a fire department telling us they couldn’t save a building because “it was on fire.” > > What dim bulbs designed this system? One of the reactors dancing with death at Fukushima Station 1 was built by Toshiba. Toshiba was also an architect of the emergency diesel system. > … > … > > TEPCO and Toshiba don’t know what my son learned in 8th grade science class: tsunamis follow Pacific Rim earthquakes. So these companies are real stupid, eh? Maybe. More likely is that the diesels and related systems wouldn’t have worked on a fine, dry afternoon. > > Back in the day, when we checked the emergency back-up diesels in America, a mind-blowing number flunked. At the New York nuke, for example, the builders swore under oath that their three diesel engines were ready for an emergency. They’d been tested. The tests were faked, the diesels run for just a short time at low speed. When the diesels were put through a real test under emergency-like conditions, the crankshaft on the first one snapped in about an hour, then the second and third. We nicknamed the diesels, “Snap, Crackle and Pop.” > > (Note: Moments after I wrote that sentence, word came that two of three diesels failed at the Tokai Station as well.) > > In the US, we supposedly fixed our diesels after much complaining by the industry. But in Japan, no one tells Tokyo Electric to do anything the Emperor of Electricity doesn’t want to do. > **[Tokyo Electric to Build US Nuclear Plants - Greg Palast](https://www.gregpalast.com/no-bs-info-on-japan-nuclearobama-invites-tokyo-electric-to-build-us-nukes-with-taxpayer-funds/)** > > I need to speak to you, not as a reporter, but in my former capacity as lead investigator ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [March 16, 2011, 3:01pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/90 "2011-03-16T15:01:10Z")
the International Nuclear and Radiological Event Scale, 1 to 7, is used to rate accidents. Three Mile Island is a 5, Chernobyl is a 7. no official rating has been given for Japan accident. Japanese officials on Saturday suggested it was a 4. French officials (a nuclear power friendly nation) have suggested a 6. it is at least a 5 from what has happened. radiation has now been detected in Tokyo. ---
**Author:** ![XT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xt/32/456_2.png) [@XT](https://boards.straightdope.com/u/XT)\ **Post date:** [March 16, 2011, 3:07pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/91 "2011-03-16T15:07:09Z")
Yeah, I read the same thing (i.e. that it’s between a 5 and 6 right now). As for the radiation in Tokyo I read that there was some trace radiation detected in a water sample (far below harmful levels) but that in subsequent samples no radiation above background was detected. Do you have a cite confirming that additional radiation is being detected in Tokyo? -XT ---
**Author:** ![Gray\_Ghost](https://avatars.discourse-cdn.com/v4/letter/g/c0e974/32.png) [@Gray\_Ghost](https://boards.straightdope.com/u/Gray_Ghost)\ **Post date:** [March 16, 2011, 3:28pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/92 "2011-03-16T15:28:27Z")
> [@matt](#): > > In theory that’s true. Not so sure in practice. I referenced this study yesterday: [http://www.sar-net.org/upload/s2-6.pdf](http://www.sar-net.org/upload/s2-6.pdf) Zirconium fuel rod cladding was electrically heated to up to 1500 deg C and air or steam blown through to see what happens. It slowly oxidised but didn’t start a self-sustaining fire or anything like it. I think zirconium needs to be more finely divided to burn. For this reason I’m a little suspicious of reports that the reactor 4 fire was a burning zirconium fuel pool fire. I’ve read a couple of reports attributing it to burning lubrication oil. Very interesting paper, **matt** , thank you for the cite. Surprising how much the zirconium corrosion varied depending on the gas composition and temperature, and when those were varied. More links to chew on. A further plug for **Eleusis** ’s mention of MIT’s NSE Nuclear Information Page [here](http://mitnse.com/). They’ve a string of quite informative posts on the Fukushima situation. I found their descriptions to be very well written, concise, yet with enough information to be informative and a clear calm tone. For those who have insomnia and need help sleeping, the NRC’s NUREG-1738 report, _Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants_ may be found [here.](http://pbadupws.nrc.gov/docs/ML0104/ML010430066.pdf) It is a very lengthy report, and as such is about a 20MB .pdf. Robert Alvarez, _et al_’s report, _Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States_ that took a much more pessimistic line on the hazards of spent fuel fires may be found [here](http://www.princeton.edu/sgs/publications/sgs/pdf/11_1Alvarez.pdf). Also a .pdf, but much smaller. Obviously these earlier reports don’t have the benefit of knowledge from the study that **matt** cited. (Which leads me to the question, has there ever been a zirconium fuel cladding fire in Western nuclear facility operations? And if so, what was the nature of that accident to get the cladding to ignite, that was missing in the zirconium oxidation study?) A question for the multitude: what is then causing the elevated radiation levels at the plant that caused many of the workers to be evacuated? I understand from the MITNSE post [here](http://mitnse.com/2011/03/15/explanation-of-hydrogen-explosions-at-units-1-and-3/), that initial elevated radiation levels were probably caused by, according to the post: > [@](#): > > Right after the explosions there were spikes in the radiation levels detected, because there were some radioactive materials in the steam. When the zirconium alloy cladding reacted to make hydrogen, it released some fission products. The vast majority of the radioactive materials in the fuel will remain in the fuel. However, some of the fission products are noble gases (xenon, Xe and krypton, Kr) and will immediately leave the fuel rods when the cladding integrity is compromised. Fortunately, Xe and Kr are not a serious radiological hazard because they are chemically inert and will not react with humans or plants. Additionally, small quantities of iodine (I) and cesium (Cs) can be entrained with the steam. When the steam was vented to the reactor building, the Xe and Kr would have followed as well as some small amounts of I and Cs. Thus, when the roof of the reactor building was damaged , these radionuclides that were in the reactor building would have also been released. This is the reason a sudden spike was seen in radiation levels. These heightened radiation levels quickly decreased. This is because there was no damage to the containment which would increase the quantities of radionuclide released, and because the radionuclides released during the explosion quickly decayed away or dispersed. But radiation levels at the plant are have continued to spike and fall, leading at one point to [workers being evacuated from the plant](http://www.chron.com/disp/story.mpl/world/7473542.html). What mechanism is causing these increased radiation levels, if it isn’t a spent fuel fire, (Thank God), and if the primary containment for the reactors haven’t been breached? > [@](#): > > Japan ordered emergency workers to withdraw from its stricken nuclear complex Wednesday amid a surge in radiation, temporarily suspending efforts to cool the overheating reactors. Hours later, officials said they were preparing to send the team back in. [CNN was quoting](http://www.cnn.com/2011/WORLD/asiapcf/03/16/japan.nuclear.reactors/index.html?hpt=T1) a Japanese spokesman that a white cloud over one of the buildings may have been caused by a breach in the containment vessel. > [@](#): > > Tokyo (CNN) – A white cloud of smoke or steam rising above Japan’s Fukushima Daiichi nuclear plant on Wednesday may have been caused by a breach in the containment vessel in one of its reactors, government officials said. > Chief Cabinet Secretary Yukio Edano said a breach in the No. 3 reactor’s containment vessel – the steel and concrete shell that insulates radioactive material inside – may have brought about the smoke. > Officials asked workers at the plant to evacuate temporarily earlier Wednesday after the smoke rose above the plant and radiation levels spiked. Authorities later allowed them to return after radiation levels fell, the Tokyo Electric Power Company said. > Radiation levels at the plant have surged and dropped repeatedly over the past few days. The most recent spike “probably” occurred “because the containment vessel in reactor No. 3 has been damaged,” a spokesman for Japan’s nuclear safety agency later told reporters. From reading the very informative posts from **robby** , **matt** , **Exapno** , and others, I know that the word “containment” may refer to many different subsystems of the reactor installation. It would be nice if they mentioned which part is supposed to be damaged. Perhaps it needs to be reemphasized that the damage and loss of life at Fukushima, in any but the absolute utter worst case, is tragic but will remain very, very minor compared to the rest of the damage caused by the tsunami and earthquake. Moreover, it is impressive how well 40 year old designs are coping with one of the largest earthquakes in recorded history coupled with a very large tsunami. Radiation certainly grabs peoples’ attention. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [March 16, 2011, 3:39pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/93 "2011-03-16T15:39:35Z")
> [@johnpost](#): > > radiation has now been detected in Tokyo. > [@xtisme](#): > > … As for the radiation in Tokyo I read that there was some trace radiation detected in a water sample (far below harmful levels) but that in subsequent samples no radiation above background was detected. Do you have a cite confirming that additional radiation is being detected in Tokyo? > > -XT my comment was based on parts of a news release from this morning (in USA) TOKYO (Reuters) – … Early in the day another fire broke out at the earthquake-crippled facility, which has sent low levels of radiation wafting into Tokyo in the past 24 hours, triggering fear in the capital and international alarm. … Officials in Tokyo said radiation in the capital was 10 times normal at one point but not a threat to human health in the sprawling high-tech city of 13 million people. … ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [March 16, 2011, 3:47pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/94 "2011-03-16T15:47:15Z")
> [@Gray\_Ghost](#): > > But radiation levels at the plant are have continued to spike and fall, leading at one point to [workers being evacuated from the plant](http://www.chron.com/disp/story.mpl/world/7473542.html). What mechanism is causing these increased radiation levels, if it isn’t a spent fuel fire, (Thank God), and if the primary containment for the reactors haven’t been breached? . First you could have a intermintent leak. Pressure or temp gets a bit high, leak gets much worse, causes the temp or pressure to fall again and leak stops/greatly decreases. Or you could have an area where some radioactive material has accumulated, like say some contaminated water in the bottom corner of one of the mostly destroyed buildings. If the wind temporarily shifts or a gust comes along, that could greatly increase the rate at which that source is releasing radioactive material into the environment. Wind goes back to normal and rate drops back down. ---
**Author:** ![Mycroft\_Holmes](https://avatars.discourse-cdn.com/v4/letter/m/a5b964/32.png) [@Mycroft\_Holmes](https://boards.straightdope.com/u/Mycroft_Holmes)\ **Post date:** [March 16, 2011, 3:58pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/95 "2011-03-16T15:58:05Z")
> [@CalMeacham](#): > > Greg Palast on Emergency Coling Systems: > > Back in the day, when we checked the emergency back-up diesels in America, a mind-blowing number flunked. At the New York nuke, for example, the builders swore under oath that their three diesel engines were ready for an emergency. They’d been tested. The tests were faked, the diesels run for just a short time at low speed. When the diesels were put through a real test under emergency-like conditions, the crankshaft on the first one snapped in about an hour, then the second and third. We nicknamed the diesels, “Snap, Crackle and Pop.” In Germany they tested the diesel generators at one of the older plants (Biblis A or B, not sure which) and actually noticed they would never have generated any electricity at all, because they had forgotten to install the coupling for the driveshaft. :smack: ---
**Author:** ![Tom\_Scud](https://avatars.discourse-cdn.com/v4/letter/t/f08c70/32.png) [@Tom\_Scud](https://boards.straightdope.com/u/Tom_Scud)\ **Post date:** [March 16, 2011, 4:08pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/96 "2011-03-16T16:08:14Z")
> [@scr4](#): > > So do I understand correctly that the “spent” fuel rods still generate enough heat to melt down by themselves unless immersed in water? Another complication (as I understand it, lots of semi-contradictory, confused sources, etc) is that the “spent” fuel rods in the #4 storage tanks are not actually spent, having been taken out of the reactor and filed there while the reactor was shut down for some reason or another. ---
**Author:** ![Mycroft\_Holmes](https://avatars.discourse-cdn.com/v4/letter/m/a5b964/32.png) [@Mycroft\_Holmes](https://boards.straightdope.com/u/Mycroft_Holmes)\ **Post date:** [March 16, 2011, 4:12pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/97 "2011-03-16T16:12:15Z")
> [@Tom\_Scud](#): > > Another complication (as I understand it, lots of semi-contradictory, confused sources, etc) is that the “spent” fuel rods in the #4 storage tanks are not actually spent, having been taken out of the reactor and filed there while the reactor was shut down for some reason or another. That’s correct. They were taken out because reactor 4 was undergoing routine maintenance. So they are not “spent” rods. The one I’m most worried about is reactor 3. There have already been statements saying that the containment was damaged, and reactor 3 uses MOX rods, which means they contain plutonium. If that stuff gets outside the containment you can stop worrying about the millisieverts. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [March 16, 2011, 4:21pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/98 "2011-03-16T16:21:15Z")
> [@Mycroft\_Holmes](#): > > The one I’m most worried about is reactor 3. There have already been statements saying that the containment was damaged, and reactor 3 uses MOX rods, which means they contain plutonium. > > If that stuff gets outside the containment you can stop worrying about the millisieverts. I dont think thats true. Now, if you wanted to compare a reactor that had never been run (or run for a very short period of time) that suddenly blew up/caught fire, yes, the one with some plutonium would be worse. But once you’ve run a reactor for awhile, its all the other really nasty stuff thats way more radioactive (and sometimes biologically active, ie it gets absorbed chemically/biologically into your body) that you have to worry about. Stuff that makes plutonium look downright harmless. Now, its possible that a running reactor with plutonium in the fuel mix has WAY more of those other really nasty things in it, but I don’t think so. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [March 16, 2011, 4:28pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/99 "2011-03-16T16:28:15Z")
When reading press releases that imply there is some “safe” level of radiation exposure, or some level that is too low to cause damage, it’s worth noting that the National Academies of Science committee took the view that there is no such thing, at least not _per se_. The BEIR VII (Phase 2) committee endorses the LNT model (Linear, No Threshold). > [@](#): > > CONCLUSIONS > > Despite the challenges associated with understanding the health effects of low doses of low-LET radiation, current knowledge allows several conclusions. The BEIR VII committee concludes that current scientific evidence is consistent with the hypothesis that there is a linear dose-response relationship between exposure to ionizing radiation and the development of radiation-induced solid cancers in humans. The committee further judges it unlikely that a threshold exists for the induction of cancers but notes that the occurrence of radiation-induced cancers at low doses will be small. > **[Read "Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR...](https://nap.nationalacademies.org/read/11340/chapter/2#10)** > > Read chapter Public Summary & Executive Summary: BEIR VII develops the most up-to-date and comprehensive risk estimates for cancer and other health effect... The short layman’s version: [ul] [li]Harm to health is dependent on exposure (linear…more=bad, less=less bad)[/li][li]There is no safe minimum exposure (threshold)[/li][/ul] This has two implications for the discussion. Firstly, it is true you are unlikely to get cancer from low levels of exposure – lottery-winner unlikely for low levels, incalculably unlikely for very low levels. Secondly, while it is reasonable for various authorities and news sources to characterize the harm from low levels as “negligible,” minuscule, or otherwise of little account, it’s somewhat disingenuous of them to characterize the situation as having “safe levels” as if there’s some line you can stay under and be completely confident. There’s randomness involved and there’s a theoretical chance from any sort of exposure. Of course, that _includes_ normal environmental exposures like going outside (or staying indoors for that matter). The takeaway: radiation levels can be low enough not to worry about, but it irritates me when it’s presented like some bad SF movie where you can stand in the radiation for 29 seconds and be safe if 30 seconds is the “lethal dose.” ---
**Author:** ![Gray\_Ghost](https://avatars.discourse-cdn.com/v4/letter/g/c0e974/32.png) [@Gray\_Ghost](https://boards.straightdope.com/u/Gray_Ghost)\ **Post date:** [March 16, 2011, 5:08pm UTC](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382/100 "2011-03-16T17:08:11Z")
Thanks for the hypothesis on the intermittent radiation spiking, **billfish**. As the quoted material indicated, the workers are back at the plant, continuing to control the situation. > [@Sailboat](#): > > When reading press releases that imply there is some “safe” level of radiation exposure, or some level that is too low to cause damage, it’s worth noting that the National Academies of Science committee took the view that there is no such thing, at least not _per se_. The BEIR VII (Phase 2) committee endorses the LNT model (Linear, No Threshold). > > [Public Summary & Executive Summary | Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2 | The National Academies Press](http://books.nap.edu/openbook.php?record_id=11340&page=10) > > The short layman’s version: > > [ul] > [li]Harm to health is dependent on exposure (linear…more=bad, less=less bad)[/li][li]There is no safe minimum exposure (threshold)[/li][/ul] > This has two implications for the discussion. Firstly, it is true you are unlikely to get cancer from low levels of exposure – lottery-winner unlikely for low levels, incalculably unlikely for very low levels. Secondly, while it is reasonable for various authorities and news sources to characterize the harm from low levels as “negligible,” minuscule, or otherwise of little account, it’s somewhat disingenuous of them to characterize the situation as having “safe levels” as if there’s some line you can stay under and be completely confident. There’s randomness involved and there’s a theoretical chance from any sort of exposure. Of course, that _includes_ normal environmental exposures like going outside (or staying indoors for that matter). On the other side of that argument are proponents of [Radiation Hormesis](http://en.wikipedia.org/wiki/Radiation_hormesis). I’ll remain agnostic regarding Hormesis or the LNT model, as I don’t believe we have a very good idea of the long term effects from widely scattered, very low levels of ionizing radiation. I would prefer not to experience any more of it than I had to, but unlike the NAS, I am unsure whether cancer rates scale linearly with decreasing radiation. The Reports from the UN Chernobyl Forum Expert Groups go into great detail as to the epidemiology and environmental effects of the disaster as of the middle of 2006. _Health Effects of the Chernobyl Accident and Special Health Care Programmes_, a report from the CFEG, “Health” can be found [here](http://www.who.int/ionizing_radiation/chernobyl/WHO%20Report%20on%20Chernobyl%20Health%20Effects%20July%2006.pdf). (.pdf) A similar report from the CFEG, “Environment”, _ENVIRONMENTAL CONSEQUENCES OF THE CHERNOBYL ACCIDENT AND THEIR REMEDIATION: TWENTY YEARS OF EXPERIENCE_ can be found [here](http://www-pub.iaea.org/mtcd/publications/pdf/pub1239_web.pdf). (Also a .pdf, sorry for the all-caps in the title.) Short version, I would’ve expected to see a lot more cancer incidence and deaths from the radiation dumped on Northern Ukraine/Belarus than have shown up so far. Accordingly, I don’t know how much the LNT model cited by **Sailboat** holds true at very low levels of ionizing radiation. [Previous page](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382.md?page=4) [Next page](https://boards.straightdope.com/t/japans-nuclear-power-plants/574382.md?page=6)