## Japan Earthquake: nuclear plants

 Quote by mheslep ..clearly the consequences of the one (Challenger) means 100% fatalities, while the other with containment equipped reactors means large capital losses and economic damage, but zero fatalities, so far.
There have been plenty of fatalities related to the release of radiation from the three meltdowns, fires and explosions at Fukushima 1.

There was a huge evacuation as result of the ongoing radiation release. During this evacuation, many people died. It is readily apparent that there is a connection between these events.

http://mdn.mainichi.jp/features/arch...na006000c.html

It is obvious there has been tremendous property, and psychological damage as well.

I recommend the contamination & consequences thread if you are interested in learning about some of the dangers of nuclear power.
 Admin Some background recently published. Code: Unit 1 Cycle BOC Date EOC Date 25 03 Nov 2007 17 Oct 2008 26 18 Apr 2009 25 Mar 2010 27A 29 Jul 2010 22 Aug 2010 27B 27 Sep 2010 11 Mar 2011 Unit 2 Cycle BOC Date EOC Date 23 28 Jan 2007 12 Mar 2008 24 24 May 2008 22 Apr 2009 25A 21 Jun 2009 17 Jun 2010 25B 19 Jul 2010 16 Sep 2010 26 18 Nov 2010 11 Mar 2011 Unit 3 Cycle BOC Date EOC Date 22 07 Jul 2006 31 Aug 2007 Outage: 15 Jun - 2 Aug 23 14 Dec 2007 24 Feb 2009 24 10 Jul 2009 19 Jun 2010 25 23 Sep 2010 11 Mar 2011 Code: Unit 4 Cycle BOC Date EOC Date 22 02 May 2007 28 Mar 2008 23 17 Jul 2008 29 Sep 2009 24 30 Nov 2009 30 Nov 2010 Shutdown 101 days before tsunami Unit 5 Cycle BOC Date EOC Date 22A 13 Nov 2006 20 Feb 2007 22B 26 Apr 2007 20 Jan 2008 23 22 Jun 2008 01 Sep 2009 24 02 Nov 2009 02 Nov 2010 Shutdown 67 days before tsunami Unit 6 Cycle BOC Date EOC Date 20 06 Jun 2006 30 Sep 2007 21 08 Feb 2007 11 Mar 2009 22 12 Jun 2009 14 Aug 2010 Shutdown 209 days before tsunami The units were mostly on annual cycles, although units 5 and 6 were managing 13 to 14 month cycle lengths. Unit 4, Cycle 23 was ~14.5 mo, Cycle 24 was 12 month. Refueling/Maintenance outages were long by current (modern) standards. The plants were operating at original ratings and had relatively low capacity factors by modern standards. I'll post the source later.
 Are there any news about the cause of the explosion of unit3? I didn't follow this issue for quite some time... For units 1 and 4 I think the explosions were caused most likely by hydrogen within the reactor building.
 Nuclear Disaster In Japan Could Have Been Mitigated, Say Industry Insiders http://www.nytimes.com/2012/03/10/wo...pagewanted=all

NRC transcript from the 17th

 And there is a notable point -- 300 feet 2 above Unit 3 in the air there is a dose reading of 375 R per hour.

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 Quote by zapperzero http://pbadupws.nrc.gov/docs/ML1205/ML12052A109.pdf NRC transcript from the 17th
Heavily redacted, lots of speculation , very much in line with chaotic conditions back then..

Misinformation about state of unit 4 spent fual pool, they thought it was gone
speculation on conditions

 mean, the dose sounds like not as much 2 a shine from the building as when the building blew 3 up. There is spent fuel and pellets and whatever all 4 over the place around the plant. So they are taking the bulldozers through and pushing the rubble in 6 piles, and they are saying that's cutting the dose 7 down, you know, 60, 70 percent.
p 74, and i wouldn't bet much on that being accurate.

 Are there any news about the cause of the explosion of unit3?
Even the Frontline show was silent on that one.

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 Personally I don't see the point in taking any of those details from the early days transcript seriously. Because its an experience we all went through in our own way at various stages of talking about the events on forums such as this one. Loads of confused details, stuff that turned out to be dead wrong, or speculation that may have lead (led?) somewhere interesting but for which no subsequent evidence emerged with which to build upon.
Thanks for saying it more eloquently.

That's where i am at too, we just dont know.
I'm done with speculating.
Waiting to see what pans out.

 Quote by SteveElbows Personally I don't see the point in taking any of those details from the early days transcript seriously.
All the other numbers I've seen in there jive with TEPCO/NISA and later reports. The interpretation is all NRC, of course, and some of it turned out to be quite wrong.

 Quote by SteveElbows The most you will get is that one day we are going to hear some more detail about rector 3's spent fuel pool, and the state of the fuel there could potentially renew a discussion about this pool having played a role in events at reactor 3 building.
Well I happen to think I just posted such a detail.

 Quote by zapperzero Well I happen to think I just posted such a detail.
Well I was meaning new detailed information about the pool and its contents, but certainly the rate you mention is of interest to this question.

I'm not used to working with R per hour numbers, did a conversion but am unsure if I did it right or not. Is 375 R/hour = 3.75 Sieverts/ hour?

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 Quote by SteveElbows Well I was meaning new detailed information about the pool and its contents, but certainly the rate you mention is of interest to this question. I'm not used to working with R per hour numbers, did a conversion but am unsure if I did it right or not. Is 375 R/hour = 3.75 Sieverts/ hour?
Your conversion is correct. 1 Sv = 100 Rem.

 Quote by zapperzero Well I happen to think I just posted such a detail.
ZZ, your detail is without context . A radiation reading was taken above the Unit 3 and, and if correct, was recorded at 3.75 Sv/hr. That is the detail. The context requires interpreting what the detail tells us. Was the high radiation due to loss of shielding water level from the spent fuel pool? Was the level from a release plume from damaged fuel in the SFP? Was the drywell Cap displaced? Was the level from shine from the drywell? Was the level from an ongoing release plume due to containment leakage? If the radiation was from I-131 it would indicate recently irradiated fuel. If it was all gamma radiation it would indicate shine instead of a plume. What is the radiation level today? We don't know enough to really say what it meams.

 Quote by SteveElbows Well I was meaning new detailed information about the pool and its contents, but certainly the rate you mention is of interest to this question.
It says "strong possibility of uncovered fuel" to me.

 I'm not used to working with R per hour numbers, did a conversion but am unsure if I did it right or not. Is 375 R/hour = 3.75 Sieverts/ hour?
100 Rem is 1 Sv, yes.

 Quote by NUCENG The context requires interpreting what the detail tells us. Was the high radiation due to loss of shielding water level from the spent fuel pool? Was the level from a release plume from damaged fuel in the SFP? Was the drywell Cap displaced? Was the level from shine from the drywell? Was the level from an ongoing release plume due to containment leakage? If the radiation was from I-131 it would indicate recently irradiated fuel. If it was all gamma radiation it would indicate shine instead of a plume. What is the radiation level today?
There is at least some context - it was measured from a JSDF helo and so it is, must be, all gamma, because that's all the military cares about - how long can their soldiers operate the equipment. It's not likely at all that someone bothered to pop a probe out the window just for the thrill of counting beta decays. In fact, I'd wager good money that they were buttoned up.

Look at that anemic plume of steam, hard to believe that the helo is getting 3 Sv/h from that (and if it was, people on the ground would have been getting it too), it's not like they are flying directly through:

The reactor well cap was not displaced, that we know of.

As for the radiation level today, that is also unknown. There are reports of dose rates on-site decreasing very significantly after the pools were watered.
 This may be the missing Unit 3 refueling crane fallen into the spent-fuel pool as seen in an April, 14 2011 image here: The graphic shows similar objects between this piece of wreckage in the Unit 3 pool and the intact Unit 4 refueling crane. It also shows a similar spacial conjunction of similar objects, and this meta-similarity makes me confident we're looking at Unit 3's refueling crane. There are many pre-tsunami photos of the refueling crane here. Why isn't the proposed refueling crane also bright green? My guess is that the fire that blasted out the south side over the pool and thus onto the crane scorched off the paint.
 Thanks for the additional info. I'm sort of with NUCENG with this one, in so much as I am hesitant to attribute the reading to a particular source with any great certainty. Especially as they were high enough in the air that I cannot claim that they were only measuring stuff that must be related directly to reactor 3. I'm basically still stuck at the point of being able to say that the fuel pools are still of interest, and that reactor 3's pool may be more interesting than reactor 4's. I expect that at some point we will learn more about this, but I doubt Im going to figure much more out in the meantime.

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 Quote by zapperzero It says "strong possibility of uncovered fuel" to me.
Sorry for asking again what was probably mentioned a dozen times in this thread, but:

Was there no instrumentation telling the SFP water level in real time, or was that instrumentation broken ?

I have the same question about temperature instrumentation.

If the fuel uncovered, how ? Was the water splashed out during the earthquake ? Or during the explosion ?

 Tags japan, nuclear