Japan Earthquake

Japan Earthquake | Page 715

good link NHK.. where did you get that one? thoughts?
by dean 4/15/2011 6:44:38 AM

Thanks, @Dean. I wonder what kind of preparedness action can be undertaken, because Japan typhoon season seems just a few weeks away... And weather quirks are most unpredictable things.
by Alblee 4/15/2011 6:45:33 AM

bull doze all the debris into a pit, cover, put protective cover over all around the plants.. to hold debris down, containment that's the key..
by dean 4/15/2011 6:48:27 AM

Wow, @Dean, sounds like a pretty tall order based on what we're seeing on the ground right now... Yet, this looks to me like must-do action no matter what ... Thanks.
by Alblee 4/15/2011 6:50:57 AM

I'm not familiar with the typhoon or cyclone seasons there but when I was in VIET NAM their storms would rip 4 foot tent pegs out of the ground
by dean 4/15/2011 6:52:31 AM

@dean I follow the NEi website so I get the daily updates.. They have tons of vids and as he mentioned labs in japan.. So I suspect some insight as well.. www.nei.org
by NHK Listener 4/15/2011 6:57:55 AM

@dean - I'm curious. How is fission prevented when fuel assemblies are removed from the reactor? As I understand it, the control rods are inserted from the bottom of the reactor. Does the simple act of removing portions of the core at one time effectively prevent fission due to a change in geometry?
by Hank Scorpio 4/15/2011 7:12:49 AM

NHK. thats the lab where my career was at.. and I consult back..
by dean 4/15/2011 7:13:16 AM

hank.. inside the core, the control rods (safety rods) have to be the right size to keep the core "sub critical"... even when all the fuel handing is done... in the spent fuel pools... the storage racks are built with lined positions with a neutron poison material to absorb neutrons, the racks keep the fuel elements fixed from forming a critical array, and the water contains a boron concentration
by dean 4/15/2011 7:15:42 AM

Melted nuclear fuel likely settled at bottom of crippled reactors

Nuclear fuel inside the crippled reactors at the Fukushima Daiichi power plant has partially melted and settled at the bottom of pressure vessels in the shape of grains, according to an analysis by the Atomic Energy Society of Japan made public by Friday.
...
The panel has also said that the fuel grains with a diameter of between several millimeters and 1 centimeter are believed to have settled flatly at the bottom of the vessels, leaving almost no possibility of a nuclear chain reaction called ''recriticality.''
...
Meanwhile, small amounts of plutonium believed to have been released as a result of the ongoing disaster have been detected in soil samples taken at the nuclear complex in Fukushima Prefecture, the plant operator known as TEPCO said.

It is the third time that traces of plutonium have been found in soil samples taken at the plant. The latest samples were taken on March 31 and April 4. The levels of plutonium in them were about the same levels observed in Japan following previous nuclear tests elsewhere, according to the utility.
english.kyodonews.jp
by estacion 4/15/2011 7:18:22 AM

@dean - I'm asking about the actual act of transferring it from the reactor to the pool. What keeps it from inducing fission as it's brought up out of the reactor and the control rods?
by Hank Scorpio 4/15/2011 7:20:04 AM

How often are control rods replaced?
by elainekirk 4/15/2011 7:22:15 AM

@dean I was trying to figure out how long they can keep up with the way they are cooling. I know they wont have additional water tanks until the end of next month. But cooling will need to go on up to 5 years. At some point they will have to recirc the water or they will run out of storage or begin transport to another facility for storage. Is it likely they will try and pull the rods from the sfp while still hot?
by NHK Listener 4/15/2011 7:23:49 AM

@NHK Listener - The long-term goal is to install more water storage and enable enough reprocessing capability to maintain the injections without spillage. My layman's take is that they will at some point be able to keep the water level in the turbine building and the utility trench from going too high. However, because there are obvious leaks of highly radioactive water somewhere in the system, I have very high doubts about their ability to stop said leak. Their best bet might actually be to inject the liquid glass they used to stop the huge ocean leak into the RPVs directly, though that would certainly end up causing the recirculation system to be completely unusable ever again and create undesirable side effects. My guess is they will continue the current process until the fuel is cooled.
by Hank Scorpio 4/15/2011 7:30:40 AM

elaine,, the control rods are given a value of so much negative reactivity .. they measure it in a unit of WORTH.. and the technical safety requirements for the facility will dictate how much negative worth the control rods must always have.. they look at the operating history on the rods and then have limits prior to removal... most reactors perform control rod worth tests as part of operations.. usually at startup
by dean 4/15/2011 7:34:11 AM

@Hank Scorpio I know that they may never be able to repair the leaks on the rpvs but the fuel ponds is what I am asking about. With all the quake activity in the area is is more likely to be a priority than an unfix-able rpv.
by NHK Listener 4/15/2011 7:34:23 AM

@elainekirk Are you asking how long a fuel bundle will last? Typ 1-2 years
by NHK Listener 4/15/2011 7:37:15 AM

I believe I remember at chernobyl of a system to maintain cooling or at least keeping water circulating through some part/parts of the plant.. I believe they will look at the existing facility for waste treament and design a cooling/circulating systems to the buildings. Once debris is removed from atop the building/main floor area.. I foresee some work to cover the reactors, establish better containment and possibly remove some of the undamaged fuel... not sure how that will happen.. ie: one at a time.. with remote controls.. into a shielded cask. of some kind..
by dean 4/15/2011 7:37:17 AM

@dean righty ho it is just I was wondering....Actually once a reactor is loaded and chuntering how long can it chunter before next stopage
by elainekirk 4/15/2011 7:38:14 AM

@nhk Really oooo now thanky
by elainekirk 4/15/2011 7:39:13 AM

commercial plants typically run for 1 year .. sometimes more ... they want to get the maxium useage out of the fuel
by dean 4/15/2011 7:39:22 AM

@dean Did you notice lots of crane activity at the waterfront today.. I wonder if we will read about it tomorrow. pointscope01.jp
by NHK Listener 4/15/2011 7:42:21 AM

@elainekirk I read today somewhere that the core shroud replacement going on in 4 was less than half way done at the time of the quake.. so rpv was flood without any doubt
by NHK Listener 4/15/2011 7:44:53 AM

NHK.. I think at some point with the NRC/DOE/IAEA, and coupled with the plans from MITSUBISHI/GE/ AREVA and other big companies,, we will begin to hear recovery plans.. got to do something to stop water and maybe the cranes are helping with those sheet metal pieces.. or clearing debris
by dean 4/15/2011 7:45:56 AM

@dean It will be some relief when there is a plan announced. Probably too late for me to get into robotics.. :-(
by NHK Listener 4/15/2011 7:48:23 AM

NHK .. this week when i traveled to work here.. I read some things going on with the robotics going there etc.. their mission will be revealed soon I think.. it's going to be a tuff uphill challenge to incorporate all the "help" being poured into Japan.. with all their rules and regulations and interfaces for doing work
by dean 4/15/2011 7:50:01 AM

www.chernobylee.com the have to be studying the chernobyl recover plan in detail for lessons learned then new design
by dean 4/15/2011 7:52:16 AM

@nhk it is many many years since I saw a prog showing the first robotic car production. I was impressed then and still am.
by elainekirk 4/15/2011 7:59:01 AM

ric.nrc-gateway.gov more read
by dean 4/15/2011 8:04:00 AM

www.ncbi.nlm.nih.gov
by dean 4/15/2011 8:04:05 AM

Oncologists want to store the stem cells of workers Fukushima in Le Monde (french newspaper) www.lemonde.fr
by Olivier 4/15/2011 8:36:48 AM

@elainekirk Could be.. Also could be them removing debris form the waterfront. Maybe we will read about it soon.. Or maybe some new before and after pics..
by NHK Listener 4/15/2011 8:43:12 AM

Tepco will remove fuel rods with giant cranes translate.google.dk
by NHK Listener edited by elainekirk 4/15/2011 8:50:41 AM

translate.google.dk

[Sorry for delay clearing you off the stuck mod queue, @xxx. I just checked in. - Alblee]
by xxx edited by alblee 4/15/2011 8:51:52 AM

TEPCO considers plan to remove spent fuel rods from crippled Fukushima plant www.asahi.com
by NHK Listener edited by elainekirk 4/15/2011 8:53:02 AM

Damage to spent fuel rods stored in the pool of the No. 4 reactor of the crippled Fukushima No. 1 nuclear power plant is limited, according to plant operator Tokyo Electric Power Co.

TEPCO on Wednesday released the results of its analysis of the first batch of water collected from the storage pool.

The concentration of radioactive substances in the sample water is higher than that in cooling water in a reactor during normal operations. But it is not high enough to raise the possibility of fuel melting. Based on the results, TEPCO presumes that damage to the nuclear fuel, if any, has been limited. www.asahi.com
by NHK Listener 4/15/2011 8:56:16 AM

@nhk why are they comparing it to reactor cooling water? one would expect cooling water from the reactor to be cool during normal ops but that is surely not comparable to the temp of water in a sfp

[er, @elainekirk, were you referring to thermal temperature? I might be wrong but the news report seemed to be referring to radioactivity and not temperature. Thanks. - Alblee]
by elainekirk edited by alblee 4/15/2011 9:00:01 AM

@NHK_Listener, from what we can deduce so far (and counting in the below report from Tepco of #4 no possibility of SFP rod melt), does it seem that the apparent radioactive debris field possibly spread out across 1 mile in radius came from, umm, Reactor #3 explosion that wrecked its SFP? Thanks.
by Alblee 4/15/2011 9:00:35 AM

-From 8:02 to 9:55 am on April 15th, an unmanned helicopter was flown overUnit 1 to 4, in order to check the condition of the reactor buildings. www.tepco.co.jp
by NHK Listener 4/15/2011 9:03:33 AM

LIVE TEPCO press gathering (Japanese only): iwakamiyasumi.com
by es edited by elainekirk 4/15/2011 9:04:59 AM

@Alblee Most likely 1 and 3 put out quite a bit of contamination from the hydrogen explosions. 3 is most likely to be the one that put out the majority of the contamination just by looking at how volatile the explosion was. If there was a fire in the sfp at the same time, that would have added to the high radiation contamination and explain the increase in trace pu as well..

[Yes, that seems to be my own macro read, especially from looking at so many photos of the the shape each reactor building is in. Thanks. - Alblee]
by NHK Listener edited by alblee 4/15/2011 9:12:58 AM

Sorry, that was the cursed Enter key thing again. Meant to read as follows...

"TEPCO on Wednesday released the results of its analysis of the first batch of water collected from the storage pool.

The concentration of radioactive substances in the sample water is higher than that in cooling water in a reactor during normal operations. But it is not high enough to raise the possibility of fuel melting."

Now what makes me visualise them cranking up the dousing then lowering the sampling bucket into the top layer of fresher, cleaner water?

Nah, surely not - getting too suspicious in my old age!
by Paul 4/15/2011 9:17:53 AM

LIVE NISA press briefing: iwakamiyasumi.com
by es 4/15/2011 9:26:07 AM

The airframes sent by Helipse are already flying over Fukushima Daiichi. Three airframes were dispatched from France last week at the request of Tokyo Electric Power.

It was designed to meet specific missions such as, the carriage of professional camera, thermal camera cooled, various sensors for measuring, surveying, carrying tank for spraying and missions of great distances.

Thanks to its payload capacity and with additional tanks flight endurance can extend to two hours , with a range of over 10 km (depending on the type of radio transmission onboard).

The diameter of its main rotor, 3 meters and its weight makes it much less sensitive to outside elements and allow it to continue its flight in strong wind, where other devices of smaller dimensions would be forced not to take the air. www.suasnews.com
by Rob in SF 4/15/2011 10:05:37 AM

Reston, VA (Vocus/PRWEB) April 14, 2011QinetiQ North America today announced that its robots and unmanned vehicles are being sent forward into the Fukushima nuclear reactor site. The company’s robotic support team has completed operator training in Japan for Tokyo Electric Power Company (TEPCO) employees.Read more: www.digitaljournal.com www.digitaljournal.com
by NHK Listener 4/15/2011 10:23:20 AM