Robots for Nuclear Containment Jobs?

They probably would have been ineffective in this case, even if they had them. They only would have lasted as long as their battery packs, ( if they weren't flooded with tsunami water), and with no way to recharge them they would have been as useless as the flooded generators.

Well I did a little search and there are lots and lots of robot designs for search and rescue, and of course Japanese designers also involved in the quake recovery effort.

But what I am wondering about are the specific tasks related to the loss of water in the spent fuel ponds, since the radiation level now prevents human operators from getting in or even flying over to drop water into the dry pond!

I did find these robots designed after Three Mile Island to help with nuclear cleanup. Workhorse looks like he could truck a hose into a hazardous area.

It's interesting, robots seem to be very task-specific in their design. Although there is a certain 'swiss army knife' look about the ol Workhorse (never used, what irony!).

I'll have a look at the links tomorrow. I'm interested in all of this, particularly the impact that the Japan event is going to have on nuclear power generation going forward. I fear that a lot of people are going to call for it to stop, which I don't think is necessary. The people that are going to be working toward the continuation of nuclear power need to be working on both the containment systems, and the argument now. It may be a tough sell.

It's an uneasy paradox, that nuclear power plants require a continuous power supply for ten days after an unexpected shutdown, even if the shutdown goes off without a hitch.

How many reactors have a guaranteed backup power system that would last for ten days in the case of a catastrophic outage. These are questions I didn't know existed until the recent days..

i have kept up to date with all thats going on in japan and find it amazing that so little back up facilities where available

in an earth quake zone and thus tsunami area you would have thought they would have put the back up generators well up the hill side

and why didn't they have emergency water storage high up thus negating the need for power to move it

why isn't the power from other nuke sites available ie site to site back up power links

as for the lack of site information haven't they heard of CCTV if there was CCTV covering all safety critical areas they could see whats happening thus supporting the information available from sensors

for a country thats supposed to be used to earth quakes they seem totally inept at emergency Planing

for all intents and purposes parts of Japan have gone back to the stone age for over a week now

I feel sorry for all hose injured or killed because of the tsunami which could have been predicted ie better protected buildings and better sea defences

and better planning for flooding ie hardened buildings high up the landscape with their own generators and independent heating positioned at strategic positions around the country

ps some of the casualties where caused because the population thought they were safe from tsunamis behind their sea defences and thus did not move when the alarm was raised

ALWAYS PLAN ON THE FOLLOWING ASSUMPTION

IF IT CAN GO WRONG IT WILL GO WRONG BETTER TO OVER ENGINEER WHILE ITS SAFE THEY TRY TO RECOVER AFTER THE EVENT

I certainly agree with the concept of over-engineering when it comes to nuclear power. The absolute consequences of a catastrophic failure are so severe, no effort should be spared to have backups and failsafes in place for every contingency.

It does seem we still have a lot to learn about managing nuclear power.

You may have been following, but you should think a little before issuing all of these criticisms. The standard practice is to take the worst estimate of an event, and more or less double it for design purposes. This earthquake and tsunami exceed the design target. Nukes are placed near large bodies of water because they need massive amounts of it. It There are many things that could be done but they make things more complicated and therefor less safe. There was no power from the other nukes because they automatically shut down in a seismic event, but in any case, the transmission lines were washed out. Normally there is an ample supply of fuel for the diesel generators. What makes you think that CCTV cameras could live in a radioactive environment?

Lastly, hardened buildings, hardened against what? these survived the quake, it was the water flooding the diesels that caused the problem. There is an optimum design that is less than the most over designed facility.

this link may help with your undersatnding of the problem

http://www3.nhk.or.jp/nhkworld/

the Tokyo electric power company is at present is trying to conect the offending power station with cables to the power grid, If these cables had been present when the reacators scrammed they would have had the power from the grid to keep the cooling running.

if the stand by generators had been positioned further up the hill behind the station they would still be running

if there had been standy by water in say a resovoir again up on the hill behind the station they would have had some water under pressure independant of electrical power, it would have bought them time.

all simple relativly cheap methods that would have saved the day.

the design of the plant was good in all other respects as it survived the quake it was the tsunami that was the killer if only they had of allowed a wider amount of back up

This link is very good

http://wordpress.mrreid.org/2011/03/12/situation-at-fukushima-nuclear-power-station/

and these will help

http://www.businessinsider.com/fukushima-nuclear-plant-2011-3

http://www.google.co.uk/search?q=pictures+of+Fukushima+power+plant&sourceid=ie7&rls=com.microsoft:en-US&ie=utf8&oe=utf8&rlz=1I7ADFA_en&redir_esc=&ei=njOCTc-1DIaChQf964jABA

http://news.uk.msn.com/photos/special-photo-galleries/photos.aspx?cp-documentid=156523016

http://www.panoramio.com/photo/49439865

fuel tanks washed away

In this case, the Fukushima Daiichi nuclear complex's back-up diesel-powered generators were built below ground level. This bunker-like positioning would protect the generators from an air strike, cyclone or typhoon-but made them more vulnerable to an earthquake-driven tsunami.

When last week's giant waves struck, they immobilized the generators despite being designed to protect against water. The tsunami also apparently washed away the generators' fuel tanks, which were above ground.

connecting outside power cables

Japan's nuclear regulator also announced that it was working to connect outside power cables to two of the units at the stricken plant, in hopes of restarting their cooling pumps. They hoped to have the cables available by Thursday afternoon.

Restarting the pumps would mark a major advance in the effort to prevent the nuclear disaster from worsening. taken from

http://online.wsj.com/article/SB10001424052748703899704576203850892933990.html

http://en.wikipedia.org/wiki/Boiling_water_reactor

explanation of disadvantages of BWR and where the Hydrogen came from extract taken from above link

Disadvantages

• Much larger pressure vessel than for a PWR of similar power, with correspondingly higher cost. (However, the overall cost is reduced because a modern BWR has no main steam generators and associated piping.)
• Contamination of the turbine by short-lived activation products. This means that shielding and access control around the steam turbine are required during normal operations due to the radiation levels arising from the steam entering directly from the reactor core. This is a moderately minor concern, as most of the radiation flux is due to Nitrogen-16, which has a half-life measured in seconds, allowing the turbine chamber to be entered into within minutes of shutdown.
• Though the present fleet of BWRs are said to be less likely to suffer core damage from the "1 in 100,000 reactor-year" limiting fault than the present fleet of PWRs are (due to increased ECCS robustness and redundancy) there have been concerns raised about the pressure containment ability of the as-built, unmodified Mark I containment - that such may be insufficient to contain pressures generated by a limiting fault combined with complete ECCS failure that results in extremely severe core damage. In this double failure scenario, assumed to be extremely unlikely prior to the Fukushima I nuclear accidents, an unmodified Mark I containment can allow some degree of radioactive release to occur. This is supposed to be mitigated by the modification of the Mark I containment; namely, the addition of an outgas stack system that, if containment pressure exceeds critical setpoints, is supposed to allow the orderly discharge of pressurizing gases after the gases pass through activated carbon filters designed to trap radionuclides^[3].
• A BWR requires active cooling for a period of several hours to several days following shutdown, depending on its power history. Full insertion of BWRs control rods safely shuts down the primary nuclear reaction. However, radioactive decay of the fission products in the fuel will continue to actively generate decay heat at a gradually decreasing rate, requiring pumping of cooling water for an initial period to prevent overheating of the fuel. If active cooling fails during this post-shutdown period, the reactor can still overheat to a temperature high enough that zirconium in the fuel cladding will react with water and steam, producing hydrogen gas. In this event there is a high danger of hydrogen explosions, threatening structural damage to the reactor and/or associated safety systems and/or the exposure of highly radioactive spent fuel rods that may be stored in the reactor building (approx 15 tons of fuel is replenished each year to maintain normal BWR operation) as happened with the Fukushima I nuclear accidents.

http://www.bbc.co.uk/news/world-asia-pacific-12733393

CCTV

use of CCTV to control robots within nuke plant

http://www.facilitycare.co.uk/Nuclear%20Power%20CCTV%20-%20case%20file.htm

Explanation of plant

http://online.wsj.com/article/SB10001424052748703899704576203850892933990.html

Explanation of the reactor in use in Japan

http://en.wikipedia.org/wiki/Boiling_water_reactor

And this one

http://en.wikipedia.org/wiki/Fukushima_I_Nuclear_Power_Plant

http://www.nuclearcounterfeit.com/index.php?s=fires+in+japan+plant

taken from above

Figures provided by Tokyo Electric Power on Thursday show that most of the dangerous uranium at the power plant is actually in the spent fuel rods, not the reactor cores themselves. The electric utility said that a total of 11,195 spent fuel rod assemblies were stored at the site.

That is in addition to 400 to 600 fuel rod assemblies that had been in active service in each of the three troubled reactors. In other words, the vast majority of the fuel assemblies at the troubled reactors are in the storage pools, not the reactors.

Now those temporary pools are proving the power plant's Achilles heel, as the water in the pools either boils away or leaks out of their containments, and efforts to add more water have gone awry. While spent fuel rods generate significantly less heat than newer ones, there are strong indications that the fuel rods have begun to melt and release extremely high levels of radiation. Japanese authorities struggled Thursday to add more water to the storage pool at reactor No. 3.

Four helicopters dropped water, only to have it scattered by strong breezes. Water cannons mounted on police trucks - equipment designed to disperse rioters - were deployed in an effort to spray water on the pools. It is unclear if they managed to achieve that.

Nuclear engineers around the world have been expressing surprise this week that the storage pools have become such a problem. "I'm amazed that they couldn't keep the water in the pools," said Robert Albrecht, a longtime nuclear engineer who worked as a consultant to the Japanese nuclear reactor manufacturing industry in the 1980s and visited the Fukushima Daiichi reactor then.

Very high levels of radiation above the storage pools suggest that the water has drained in the 39-foot-deep pools to the point that the 13-foot-high fuel rod assemblies have been exposed to air for hours and are starting to melt, he said. Spent fuel rod assemblies emit less heat than fresh fuel rod assemblies inside reactor cores, but the spent assemblies still emit enough heat and radioactivity that they must still be kept covered with 26 feet of water that is circulated to prevent it from growing too warm.

Gregory Jaczko, the chairman of the United States Nuclear Regulatory Commission, made the startling assertion on Wednesday that there was little or no water left in the storage pool located on top of reactor No. 4, and expressed grave concern about the radioactivity that would be released as a result. The spent fuel rod assemblies there include 548 assemblies that were only removed from the reactor in November and December to prepare the reactor for maintenance, and may be emitting more heat than the older assemblies in other storage pools.

Even without recirculating water, it should take many days for the water in a storage pool to evaporate, nuclear engineers said. So the rapid evaporation and even boiling of water in the storage pools now is a mystery, raising the question of whether the pools may also be leaking.

Michael Friedlander, a former senior nuclear power plant operator who worked 13 years at three American reactors, said that storage pools typically have a liner of stainless steel that is three-eighths of an inch thick, and they rest on reinforced concrete bases. So even if the liner ruptures, "unless the concrete was torn apart, there's no place for the water to go," he said.

At each end of a pool are 16-foot-tall steel gates with rubber seals, used to swing fresh fuel rod assemblies into a reactor and to swing out and store the spent assemblies. The gates are designed to withstand earthquakes, Mr. Friedlander said, but could have sprung leaks given the power of last Friday's quake, now estimated to have had a magnitude of 9.0.

Even if water gushed out of the gates, there would still be about 10 feet of water left on top of the fuel rod assemblies.

When the water in a storage pool disappears, residual heat in the fuel rods' uranium left over from their time in a nuclear reactor continues to heat the rods' zirconium cladding. This causes the zirconium to oxidize, or rust, and even catch fire. This breaks the seal of the rods, and pressurized radioactive gases like iodine, which accumulated in the rods while they were in the reactor, suddenly spurt out, Mr. Albrecht said.

Each rod inside the assembly holds a vertical stack of cylindrical uranium oxide pellets. These pellets sometimes become fused together while in the reactor, in which case they may stay standing up even as the cladding burns off. If the pellets stay standing up, then even with the water and zirconium gone, nuclear fission will not take place, Mr. Albrecht said.

But Tokyo Electric said this week that there was a chance of "recriticality" in the storage ponds - that is to say, the uranium in the fuel rods could become critical in nuclear terms and resume the fission that previously took place inside the reactor, spewing out radioactive byproducts. Oh Great it gets worse

CR4 Admin: deactivated broken link. Website no longer exists. 12/28/2018

http://www.facilitycare.co.uk/Nuclear%20Power%20CCTV%20-%20case%20file.htm

Ah. I was not aware of this Bruce, and didn't see it discussed in the links. That is a serious obstacle to using robots in a nuclear disaster.

I think a lot will be learnt from this tragedy, but hind sight will always be 20/20

I'm not entirely sure what military vehicles Japan has in the area, but a number of types are 'radiation hardened'.

Seems to me though it would have to be a sizable HP large device to drag and insert a big enough hose.

This is going to sound very callous and cruel, but, I wonder if Asian elephants could be trained to work under remote control, and deployed for this sort of task.

I wondered the same thing from the start. Having worked at Westinghouse Nuclear Services Division years ago during the building and troubleshooting of some of their first generation robotics, I assumed that the Japanese, who are continually praised for their engineerings skills would have had these as they always worked closely with us on the projects. I went from the first stages to, eventually, the 3rd generation and was impressed. You have all seen or heard of their use at TMI. They are powered by umbilicals with cameras and joy stick operation, if needed, by a trained technician. During the last few years, I have been to US Nuclear Plants on QA assignments and the newest versions of what we did years ago has advanced so far, it would be hard to describe. Like the Japanese are accused, here in the US, all has to be top secret, so the public is not aware of the capabilities.

Do robotics make better inspectors and eliminate the need for human interface. A resounding no, especially if the findings are put into a RBI type of plan. There are way to many potentials for fault out there that were found by myself and others, that were pencil whipped by engineering and management.

But in the relatively simple aspect of using robotics to cool the fuel, with the self contained and portable power generators brought in, it could and should have been done.

I believe there is Japanese technicians at the plant who are crawling around inside the building to look for and hopefully plug leaks in the storage pools.

any of us would sacrifice our lives doing this to save 10 million people in the surrounding area wouldnt we ? , call it ethical kamikaze .

robots could be useful in many areas but debris inside the reactor buildings might stop their useage even if you did set them up with lead shielding to protect the electronics from radioactivity.

what bugs me is why they didnt bring in gensets to hook up to the plant on day one ?

1000 kVA gensets are a dime a dozen and wouldnt have taken more than a few hours to bring online

or alternatively use heavy helicopters to run power cables over land to hook up to the pumps and infrastructure , the hell with safety , just run the cables over the top of the debris field to reach the reactors .

it should have been done on day 1 not day 7.

I wonder if the poor information coming from the government is because the plant was reapproved for use when it should have been decommissioned... will investigations uncover an innappropriate relationship between govt and the owner operator of the nuclear plant ?

and on the topic of safety , why didnt the oil refinery have redundant fire protection systems ?

Oil terminals i have worked on had ring-main sprinkler piping , multi point pumping stations , backup gensets , fire rated cabling and control systems , and looped expansion points in cable racking and conduits to prevent breakage of cables during earthquakes.

that refinery fire should have been doused with its own built in fire protection system , instead they lost the whole lot and let it burn itself out.

Now factor in meters of mud mixed with debris of broken buildings and bodies.

Then there is the congestion of access; by injured, dead, and those trying to aid and comfort.

Then there is the tasking prioritizing of materials and resources against who can be saved and who is left to die.

And that, my "I don't get it" friend, is just the 'tip of the iceberg' Emergency Services have had to face.

If I sound a bit 'p o', it's just due to the bleating of; "we're down wind and they should'a aught'a done something", that seems the prevailing attitude across these threads.

But if you must should'a aught'a, what about GE who (I'm told) designed it?

And by mentioning GE, we now go to the US government, the old AEC, the now NRC, and the in bed with the utilities and manufacturers.

The US worked with GE and approved the Mark 1 design and our research and studies warranted other countries to accept it during those times.

In other words, the finger pointing can continue indefinitely.

I think natural instinct or as the west likes to call it, common sense, was out of play on this one.

I agree about the gen sets - I don't understand why the military couldn't get them in there on day one. Yes I'm afraid we'll learn some awful lessons from this one.

"The ministry also plans to mobilize GSDF's two Type 74 tanks to remove the rubble at the plant, which is hampering the water-spraying efforts. It is extremely rare to use such tanks in actual missions.

A ministry official said that the decision was made because the vehicles are "more airtight and have high protective capability against radiation," suggesting the tough conditions in which the SDF and firefighters are placed."

Maybe they've have been reading your thread.(#17)

Link

Right on. Rare missions for rare tanks, is what it is.

Very glad to see they're getting the upper hand.

It looks like they have come up with a 'lateral' robot idea.

From http://www.asahi.com/english/TKY201103220159.html

"In addition to water spraying by the Tokyo Fire Department and the Self-Defense Forces, TEPCO workers were also preparing a concrete pump vehicle that can spray water by remote control from a height of about 50 meters."

Not so good is;

"The suppression pool connected to the core containment vessel of the No. 2 reactor is believed to be damaged."

Wow, that is a super cool machine.

I think it was a design error to have the containment pools on top of towers - very subject to damage in a case like this and of course, water running out. Then again, if a quake is likely to rip up the ground, where do you go with your containment pool... It is not a good situation for nuclear waste.