Japan Earthquake | Page 2595
@dean catch you laterby elainekirk 11/2/2011 2:31:20 PM
Have a good one Dean, will keep notes if I find anything more on this todayby lillymunster 11/2/2011 2:33:17 PM- @elainekirk Only used once radium facial mask - gives that youthful glow. :-)by lillymunster 11/2/2011 2:34:00 PM
by lillymunster via Farm5.static.flickr 11/2/2011 2:37:08 PM- @lillymunster nooooooooooooooooooooooooooooooooooooooo omgby elainekirk 11/2/2011 2:37:49 PM
Recriticality www.zerohedge.comby bojack54 11/2/2011 2:54:42 PM- Morning Bojack!by lillymunster 11/2/2011 2:55:43 PM
- Heyby bojack54 11/2/2011 3:00:00 PM
- Anybody got a link handy to that recent report that shows radioactive iodine near Fuku, I think it was in rice?by bojack54 11/2/2011 3:00:58 PM
- @bojack54 that was me - let me see if I can dig it up, just a sec.by lillymunster 11/2/2011 3:04:21 PM
- Here it is, blog post links over to the CRMS results of rice with I-131 harvested in Oct. fukushima-diary.comby lillymunster 11/2/2011 3:05:42 PM
UDPATE3: TEPCO finds sign of nuclear fission at Fukushima reactor
TOKYO, Nov. 2, Kyodo
(EDS: UPDATING WITH CONFIRMATION OF XENON, ADDING HOSONO'S COMMENTS)
Tokyo Electric Power Co. said Wednesday it has detected signs of a recent nuclear fission in the No. 2 reactor at the crippled Fukushima Daiichi power plant, touching on the possibility that the melted fuel inside may have gone critical temporarily.
The existence of the nuclear fission by-products was confirmed later in the day, suggesting the plant's seemingly stable situation could be fragile, almost eight months after the nuclear crisis erupted in the wake of the March 11 earthquake and ensuing tsunami. english.kyodonews.jpby Edano 11/2/2011 3:07:01 PM- TEPCO: Reactor may have gone critical
The operator of the crippled Fukushima Daiichi nuclear power plant says it found in the facility's No.2 reactor radioactive substances that could have resulted from continuous nuclear fission.
The Tokyo Electric Power Company, or TEPCO, said on Wednesday that it detected xenon-133 and xenon-135 in gas taken from the reactor's containment vessel on the previous day. The substances were reportedly in concentrations of 6 to more than 10 parts per million becquerels per cubic centimeter.
Xenon-135 was also detected in gas samples collected on Wednesday.
Radioactive xenon is produced during nuclear fission.
The half-life of xenon-133 is 5 days, and that of xenon-135 is 9 hours.
TEPCO says the findings suggest that nuclear fission may have occurred recently, not just after the March 11th accident, and that a state of criticality could have occurred temporarily in some areas.
TEPCO workers poured a boric acid solution into the reactor on Wednesday to suppress nuclear fission.
The utility says it has not found any significant change in temperature and pressure of the reactor, and that large-scale criticality did not occur.
TEPCO says the reactor's cooling process is continuing and that the firm expects to achieve cold shutdown at the plant this year as planned. But the utility also says it wants to take a close look at the situation of the plant's No.1 and 3 reactors.
Wednesday, November 02, 2011 20:37 +0900 (JST)
www3.nhk.or.jpby Edano 11/2/2011 3:07:27 PM 
english.kyodonews.jp
No. 2 reactor building of Fukushima Daiichi plant
Supplied photo taken Oct. 20, 2011, shows the fifth floor of the building housing the No. 2 reactor at the Fukushima Daiichi nuclear power plant in Fukushima Prefecture. (Photo courtesy of Tokyo Electric Power Co.)(Kyodo) english.kyodonews.jpby Edano via English.kyodonews.jp 11/2/2011 3:08:30 PM- The rice issue and TEPCO's claims do not make sense. TEPCO has been saying for months there is no I-131 detected. There had to be a significant amount in order to contaminate rice and it had to be fairly recent to show up in the rice.by lillymunster 11/2/2011 3:10:00 PM
- it seems they still find xenon today.by Edano 11/2/2011 3:12:10 PM
- Thanks, @lilly bojack.orgby bojack54 11/2/2011 3:13:50 PM
@lillymunster, exactly why I could not make sense of this either. The release at the reactors should be greater than what was found in the rice. 'Below detection' could not be an entry in the tepco charts. Where then does the iodine originate?by Peter 11/2/2011 3:13:52 PM- @Peter The only thing I can think of it TEPCo is lying about iodine releases. I keep trying to find any other excuse for the iodine in the rice and can't find one. I would think CRMS is skilled and reliable enough to do the tests properly.by lillymunster 11/2/2011 3:18:28 PM
- added a post about the recriticality and the rice. Mentioned the confusion with the NISA statement about fuel at unit 2 and that they don't know if it is in "containment" houseoffoust.comby lillymunster 11/2/2011 3:40:21 PM
- @lillymunster , that would constitute a dumb crime, and would be found out on short notice. How about the thyroid checks of the workers? The workers would show it to some degree. If there were continued releases from the reactors, tepco could not keep it under wraps indefinitely. I do not doubt the finding by CRMS, but have not a clue where else the iodine could stem from.by Peter 11/2/2011 3:40:50 PM
- @Peter This is TEPCO - the short in the system seems to be their PR office. What is going on at the plant and what is being released in documents and press conferences don't have to match and IIRC TEPCO is voluntarily releasing this information so they have no obligation to be honest. This is also the same crew that tried to tell the public everything was under control while they were preparing to flee. The corporate office is something else.by lillymunster 11/2/2011 3:45:11 PM
- @lillymunster , the workers would notice. Perhaps we can ask irockhopper whether she heard anyone noticing a higher thyroid count.by Peter 11/2/2011 4:20:16 PM
- @Peter how would they check other than WBC?by lillymunster 11/2/2011 4:21:23 PM
- @lillymunster , remember the pictures of the rad techs holding detectors to the necks of guys filing out of the plant? These checks must still be going on. In addition, new crew must have been whole-body counted. I wonder what happened to the guys who explored the isolation condensers. If they walked through a cloud of iodine, they'd know.by Peter 11/2/2011 4:28:14 PM
@all Good Morning...Good Evening...Hello!by smoss 11/2/2011 4:47:33 PM- @all Chernobyl 10 years on and the possibility of re-criticality: Possibilities of recriticality have been widely investigated. It has been found that the sarcophagus is currently safe from a criticality point of view. Nevertheless, it cannot completely be excluded that there exist configurations of fuel masses inside the sarcophagus which could reach a critical state when in contact with water. However, even if this could lead to significant radiation fields inside the sarcophagus, neither large off-site releases nor mechanical effects would have to be apprehended in such an event. The impact on the operating personnel of the other units should also be clarified.
www.iaea.orgby smoss 11/2/2011 4:52:36 PM - Hi Smoss!by lillymunster 11/2/2011 4:57:34 PM
backby dean 11/2/2011 5:10:58 PM- @lillymunster Hi! @dean Hi!by smoss 11/2/2011 5:12:02 PM
- @dean I have a question for you...I was reading through this article on recriticality at Chernobyl and how they delt with the situation there in the early 1990s. It mentions postive and negative feedback when criticality is reached and that negative feedback is preferred to positive feedback. Would this apply to Fukushima and is this effecting their decision making with the Boron? Chernobyl used gadolinium instead, was that because of the graphite?by smoss 11/2/2011 5:15:53 PM
- @dean This is the article: www.osti.govby smoss 11/2/2011 5:16:45 PM
- @dean Didn't mean to ambush you :-)by smoss 11/2/2011 5:20:13 PM
- hey smoss. how you doingby dean 11/2/2011 5:21:49 PM
- just a minby dean 11/2/2011 5:21:57 PM
- dang.. my entry wasn't saved..by dean 11/2/2011 5:29:36 PM
- @smoss.. the idea of over or under moderation in reactors containing water determines when there is positive (under moderation) or negative (overmoderated) reactivity. thus when more water is added the reactivity can go down or up... it's based on the moderation efficiency for neutrons to thermalize....by dean 11/2/2011 5:30:28 PM
- @smoss, for a reactor the over or under moderation in a reactor with water determines the positive (undermoderated) or negative (overmoderated) reactivity affects on Keff.... thus in an undermoderated reactor where the Keff is <1 additional water will result in the Keff coming closer to 1by dean 11/2/2011 5:31:40 PM
- there are also affects from the thermal reactivity feed back.. ie: as temp increases power can go up or down and vice versaby dean 11/2/2011 5:32:41 PM
- most reactor designers like an over moderated reactor or one with negative thermal reactivity so when temp increases reactivity goes downby dean 11/2/2011 5:33:24 PM
- @dean So by their design nature and aftermath of accident situation, Chernobyl was undermoderated situation, compared to the overmoderated of Fukushima?by smoss 11/2/2011 5:34:19 PM
- Gadolimium and Hafnium are excellent choices for control because they have such large cross section for absorption of neutrons (they gobble them up like mad).. and,, in accident conditions their absorption cross section increases as temp increasesby dean 11/2/2011 5:34:35 PM
- additionally.. their daughter products also have high absorption cross sections for neutronsby dean 11/2/2011 5:35:09 PM
- the reactor by design from an overmoderation standpoint.. can change based on the RUBBLE/DEBRIS and would be hard to predict.. however, having said that,,, if they tool water out of FUKU and there were more fissions of evidence of them one could say the reactor was over moderated... and like wise if evidence of less. the oppositeby dean 11/2/2011 5:38:36 PM
- tool=tookby dean 11/2/2011 5:39:02 PM
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