A Question About the Japan Nuclear Accident

They have spent fuel rods, kept on site in a pool, which may or may not be boiling dry.

Many conflicting reports around.

Check out this blog:

http://www.guardian.co.uk/world/2011/mar/15/japan-nuclear-crisis-tsunami-live

There are reports of a spent fuel storage pond on fire, with fission products being released directly into the atmosphere.

This is horrible if accurate.

This seems like this type of thing would never happen. My assumption was that spend fuel was stored with sufficient separation such that criticality would be impossible due to the geometry....

This is such a sad thing. Horrible for the people in Japan and their losses. Horriblefor the world in that it will surly present resistance to new nuclear power plants.

Even with all this loss, the total number of people lost and the total amount of radioactive contamination released into the environment is a tiny faction of the people lost and radioactive contamination released by energy production from coal. This is true whether you consider gross totals, or per kwh produced.

Nobody knows the extent of losses now, nor will they in future except through comparison of cancer rates, both downwind and within the proximity compared to a presumed unaffected control population, far into the future. If production of coal is compared, then mining and refining of uranium must be considered. Unfortunately, the full lifetime cycles are seldom taken into account in the use of any power source. I hope engineers can influence policy makers to include all the consequences of each power use, from mining to garbage heap. This catastrophe has illustrated design flaws; a lack of adequate venting of built up hydrogen, and storage of spent fuel at the reactor. Are newer designs more sensible?

If I see a dangerous pressure buildup in my vessel and have no door no tube no nothing to open I would take a drill or a bullet to generate an opening to relieve the pressure.

They are trained for reading big handbooks but not to counteract emergencies.

Any local firefighter squad would have done better. Especially with the fire in the cooling pond of used fuel rods - the US Navy did the work.

RHABE

Is it that simple to make a hole with a drill or a bullet to relieve the pressure? Definitely, many brains of nuclear experts from world over must be working on a solution to contain radiation to the best possible extent. I think it is wrong on our part to simply pass comments against someone.

They did not think that hydrogen buildup may be so severe to burst the containmant!

Contain radiation - ok - but not atthe risk to spoil much more!

My suggestion is an absolute emergency measure.

Any planning (in advance) action would be immediately replacement of oxygen by nitrogen (or may be carbondioxide) and catalytically burning the inside hydrogen with controlled inlet of air through porous carbonfilters that are impregnated with platinum.

This is giving "cold" combustion and producing some water.

So where is the problem?

Why have they not been able to bring the cooling back to acceptable levels? If at the first one they shoul have learned!

RHABE

We should remember whole plant and the equipments must be in bad shape due to earthquake and flooding due to tsunami. The problem is aggravated with higher radiation levels near the plant sue to recent reactor explosions, which would make it difficult for any human being to go near the plant to salvage the situation. I guess, seawater cooling was thought of as an simple and easiest possible (may not be the best) emergency measure. I read today about cooling the burning spent fuel ponds by coolant from helicopters. I am not sure if this is true and have no idea how far will this be successful.

Forgotten that three mile island disaster?

There was a program some years ago on tV showing an airplane crashing into a reactor housing. The airplane disintegrated, but the reactor housing appeared undamaged. I believe your bullet theory would fail.

of course that is how the twin towers were designed also, and then the technology of airplane changed (or at least that is what they blamed the collapse on).

This was a different type of reactor,

the Japanese reactor-housings that are blown up now are not design to withstand any big pressure nor impact.

Inside these housings is the big pressure vessel made from steel with wall thicknesses above 20cm (8"). Inside these are located the now partially damaged/molten fuel rods.

If the zirconium tubes around the fuel rods are melting (near 1200°C) then the contained radioactivity is escaping. The volatile components first.

RHABE

Actually, this CAN be known with a high degree of certainty. Comparing the release of radioactive material into the environment of coal power versus nuclear power, inclusive of all significant processes:: mining, refining, transport, leaks, accidents (accounted as an average bases on frequency / severity) etc is a good place to start if you want to know something now, instead of waiting for data on mortality.

There are some quality academic paper available. The concensus is that coal powered plants release about 100 x the radioactive contamination of a similarly sized nuclear plant. [r The fact is, the average coal power plant dump literally tons of uranium and thorium into the environment every year. If coal was required to account for release in a manner similar to the way nuclear power must account, coal would not be price competitive with even wind or solar.

The comparison is not difficult.

Spent fuel is as good as a reactor under sleep. You can wake it up and have nuclear explosion or leakage of Radiation into environment. If safely stored and there are no great disaster around then things may look all right.

I think, countries like Japan, UK and many other small countries having waiting trouble near see must not take too much risk.

Radiation leak is a problem of many years to come. It makes people and Governments to think twice if the risk is at all worth to face such high trouble at some point of time. It is like living on Volcano. So far so good and there comes a moment and entire world feels the tragedy.

Cooling water resource and minimum power requirement to run the system is essential to keep the nuclear facilities safe. Building them at unsafe places is absolutely wrong.

People of Japan take much greater risk than the people of other parts of the world. It may be an acceptable way of life there. The tool of life is lower means they have better technology but they may not be prepared for such a high risk. You can not predict if much greater risk will not be imposed in time. You may all know about the risk San Francisco is facing. It is a risk in waiting and with no great preparedness for it. It may be worst than Mexico City disaster.

Sea water makes easy way to have nuclear reactors near sea where lots of water is available for cooling the reactor systems and dilution of radioactivity and heat is much easier. Other alternatives are large rivers but water from rivers is used by people and contaminating them is going to be a serious problem. Transporting cooling water from sea at some 50km inside land may be ideal and nuclear reactors can be placed away from sea. Alternative water resource is also essential in emergency.

Neutrons escaping from fuel become Hydrogen, which finally explodes and causes all shorts of problems.

One of the differences when speaking about the Japanese nuclear program is that they use fast breeder reactor technology to breed down and reuse their spent nuclear fuel instead of simply stockpiling it. This is not a new or even radical technology/approach, it is simply the logical way of dealing with the spent fuel rods. We could do the same, but President Carter pushed legislation through congress making the use of or even contemplating the use of this technology illegal. Until we have a president and a congress with enough intelligence to stand up to the eco-terrorist on the left we can only stockpile the waste.

Hmm, if contemplating the use of such technology is illegal, why did you jsut contemplate its use. does this mean you will be spending soem time in Leavenworth KS?

Fast breeders are dead since a long time.

RHABE

"Neutrons escaping from fuel become Hydrogen, which finally explodes and causes all shorts of problems."

I don't believe that this pathway is of important.

The hydrogen is generated from the decomposition of water by red hot metals that react with the oxygen from water to give oxide. The tubes surrounding the (oxide) fuel pellets are made from zirconium, so this is converted to oxide or hydroxide and hydrogen is freed - to react with the oxygen of the air.

At very low percentages hydrogen in air the mixture is not combustible but the hydrogen can be reacted with oxygen to water if catalytic action by platinum is existing.

At medium percentages the mixture will burn if supported by a pilot flame. This is the region where safe combustion may take place.

At high percentages a deflagration or detonation will happen. These percentages can only be handled safely if the oxygen is replaced by hydrogen at an early stage so that simply there is not enough oxygen neither for flames nor detonations. In this situation the hydrogen pressure can be brought down by an inverted flame: blowing in some oxygen or air through a catalytic wire-net with means to ignite the mixture.

RHABE

Gases are released through stack. We have stack perhaps 300m to 500m high for both reactors and fuel storage.

http://www.barc.gov.in/

"Gases are released through stack. We have stack perhaps 300m to 500m high for both reactors and fuel storage."

I read your words but don't understand the meaning.

Can you explain?

RHABE

open this website www.barc.gov.in and see two reactors and both have those tall stacks to release gases in atmosphere to dilute the radioactivity.

Hmm, I am more interested in how the neutrons become hydrogen. It seems that obviously there were some steps in the process left out, an for the life of me my chemistry degreee is not helping me with this one. Considering that hydrogen is comprised of 1 proton and 1 electron (except heavy hydrogen isotopes like tritium and deuterium). I would be interested in hearing more about this conversion process by which a neutron gets translated into a hydrogen atom (molecule).

Although the poster is incorrect about the amount of hydrogen contributed (the amount produced is too small to present much of an explosion hazard), the poster is correct in asserting hydrogen is produced by free neutrons.

Free neutrons have a half life around 10 1/2 minutes (some say 10.3, some say 10.6). Neutrons beta decay, yielding a proton and an electron, so mass, energy, and charge are conserved.

Conditions occurring in a neutron flux are not well explained by standard chemistry. The element constituents a system in a neutron flux can no longer be assumed an immutable constant.

If neutrons decay that quickly, why were they so difficult to detect when I worked at Argonne 41 years ago? The beta decay should have been detectable.

In your work at Argonne, were you measuring for beta decay in a space with a large population of thermal neutrons?

In free neutron beta decay, the new electron can have kinetic energy up to around 1.7 MeV. This is fairly high energy. Certainly well above any minimum threshold for detectors (even 40 years ago).

In an area with a large population of thermal neutrons there are likely to be numerous event with energies well above the maximum for free neutron beta decay, largely dependent what else is in that area.

Whether from a free neutron to a proton and electron, or within a relatively unstable nucleon with an excess of neutrons to a relatively more stable nucleon with one less neutron and one more proton (plus an ejected electron), beta minus decay always involves a neutron changing into a proton and electron (and technically an antineutrino).

So, what were you working on at Argonne?

If neutrons to decay that rapidly, wouldn't all atoms larger than hydrogen decay into hydrogen in a matter of minutes? Why are they so much more stable in an atom? Or are we talking about decay through collision.

Neutrons decay when there is an unstable excess of neutrons, be it in a nucleus or as a free neutron.

This is not an unusual or exceptional type of beta minus decay....it is the only type of beta minus decay. Beta minus decay is rearanging to a lower energy level away from an excess of neutrons .

neutron --> proton + electron + antineutrino and some energy.

The only other type of beta decay is beta plus decay, occurring when an excess of protons exist. A proton yields a neutron, a positron and a neutrino.

No worries about everything being reduced to hydrogen. There are many stable combinations....

Neutrons do not decay inside nucleus in stable atoms. They can do something this kind of activity only in some radioactive isotopes (235-U) on when triggered by neutron hit (238-U).

Decay is a statistical process. Decay process also has a half life time so not all neutrons will disappear at once.

No one knows if anything is permanently stable. Perhaps anything and everything changes but some may take enormous time beyond our measurement capabilities. We can call them stable.

Neutrons have quality factor 20 (due to LET) or they can harm 20 times more than x-rays. Neutrons can cause cataract and blindness after five years of exposure even in children. It is N-P scattering that causes damage due to heavy mass of proton. Energy transfer is nearly 100% due to nearly equal mass and Billiard ball like collision. Hydrogen is plenty in human body which is available as good energy absorber target.

Water vapor breaks down, dis-associates into free H2 and O2 over hot or molten metal. A molten charge will absorb some of the H2 causing "gas porosity' in the metal charge if not removed - purged- degassed. Since the spent rods were not molten the H2 would not be absorbed but the spent rods were only in Reactor #4 so it would not explain the H2 explosions in #1 and #3 reactor which were the first to blow out the reactor buildings. I would tend to agree that the source of a sufficient amount of H2 was not that.

So if spent fuel rods have a lot of energy left, then I guess they are not really "spent". Why can't they be used as fuel any longer? Just curious.

You can think of them as embers, which only have enough of the "good stuff" left to heat themselves + local surroundings. If left in the reactor, they wouldn't produce enough heat to generate sufficient steam to run the turbines.

Spent fuel can be reprocessed and used again. However, the known process leaves more weapons-grade fuel, which has to be stored with even higher security than the original spent fuel!

Even so, several new reactor types are being designed to re-use "spent" fuel. China has announced that they will be doing just that.

"Spent fuel can be reprocessed and used again. However, the known process leaves more weapons-grade fuel, which has to be stored with even higher security than the original spent fuel!"

"reprocessed and used again", Yes, most of the uranium is still not burnt.

"However, the known process leaves more weapons-grade fuel" No, this plutonium in the used fuel-rods is only weapon grade if the fuel rods are reprocessed after only a few days or weeks of usage. Or it can be made into a nuclear weapon with the most sophisticated construction and using any possible trick - these are known only to the old nuclear-weapons nations. And they prefer the much better stuff from early reprocessing or highly enriched uranium.

RHABE

Plutonium from spent fuel is a problem and it was planned to be used in Fast Breeder reactors as trigger source of chain reaction. Indian Fast Breeder reactors to use liquid Sodium as coolant and I am not sure of what they use in Japan. Water and Sodium do not go together and Tsunami + Earthquake make a goos recipe just for that.

Good to have you here Shyam

I wonder how high you estimate the chances of something similar happening in your country or the neighboring Pakistan. Are any measures being taken to learn from what has happened in Japan?

I remember earth quakes in your part of the world that could do a lot of damage to now existing nuclear power plants. God forbid!

If we are not pragmatic about this we lose the flow of information (which flow of information?) and that would be like having a skeleton in the cupboard. (English saying for having something to hide).

How is the nuclear industry reacting to this in your part of the world?

Google is not going to get me far, maybe you have a link?

All the best, Ky.

Thank You

8

I just found this in CR4. Any comments? Too bad to be not true?

As I have said in earlier postings that some new nuclear reactors are under plan that are to be set up by foreign agencies.

These are perhaps more under International politics than any other thing. There was USA embargo on India after just one or two nuclear tests. Giving business assurance to foreign nations removes that embargo. This maybe a clever deal to make the environment free of old feelings.

It takes many years to set up reactors. Indians will be all around to see what these people are doing and they can easily through out or arrest anyone doing wrong anywhere. Perhaps India can push blame on foreign Government of their incapability if they do any wrong here and IAEA will put pressure on so called developed countries and restrict them from damaging the world. India can even allow foreign agencies to run the reactor and let them get killed there if they do wrong thing.

There are nearly 200,000 people in atomic energy in India and very large work force and talent but they are not asking them to build these reactors so what is the point.

Bhopal tragedy was worst thing to happen and perhaps India was not geared for facing any such disaster. However, people know what to look for.

India can afford to give all its money to developed countries for getting things done in India. It is good thing for both of them and also for intermediate people who want money but do not work for it.

There are not many countries like India and you will never know how this country really runs its business. There are all shorts of ideas here that flourish and land is fertile for anything and everything you can imagine. It will be a Ph.D. work for many to understand our nuclear policy as after working for 22 years there I hardly could understand anything seriously.

I looked at the morning news that at the New Delhi airport people were to be scanned for Radiation after reaching from Tokyo but none was scanned. They had all equipments there but none to do the job. Entire team was missing and only TV channel people did their job by catching the Government on wrong foot. Now Government will sure warn those people who did not do their work seriously. If they were doing their job then we might have seen there faces on TV but they were not to be there at the right time.

Food from Japan will have very dangerous radiation deposited in fish and all sea food for lots of time now. No one should eat any food items coming from Japan else will run a serious risk of bone or blood cancer and death. This will last more than a year. Think of people of Japan who have less than 40%food on land and live on sea food. They will kill whale and Dolphins at Antarctic to eat them for years now as food nearby is ll contaminated. Giving contaminated food to their people may be accepted by the Government of Japan under food scarcity so be careful if you are visiting them.

I think India Government should donate lots of food for Japan as will will not matter to India to feed the entire population of Japan for one full year. I will support my India Government if they do so and I think all Indians will happily accept it.

Very informative, thank you.

There is so much work to do, on all fronts. Technical, humanitarian, logistical and the fat lady hasn't even started singing yet.The best out come would be that humanity unites without a beggar or president in charge. Let the strong support the weak.

This spectacle of a failure will have unimaginable consequences on all and sundry. The magnates of the nuclear industry will have to rethink. Nobody wants to lose decades of investments. It's just such a pity that there could be a very viable way to harness this energy in a safe and recycling orientated way and with a master plan which should include an exit strategy.

The lack of these exit strategies are the cause for the escalation of an uncontrollable process, system, materials,......... Lack of power to supply the cooling cycle with water, in a power plant??, my lovely behind. My garage has more battery storage capacity.That is a failure which could have been evaded. But then again how would bloody I know?

If it was me I would 'sacrifice' (_?) a bit of my power consumption compared to the consequences of unlimited power all of the time and through that inviting such a disaster or other undesirable consequences such as in Bhopal, to happen.

If more people would be a little bit more modest and humble about life all would be better off. It is the extremes on both ends of the equation (YES/NO nuclear power) that make the waves and rock the boat. If me reducing my consumption by 50% would help out another person in Japan I would do so. It just doesn't work that way, I know.

Please anyone with Japanese friends tell them that my heart goes out to them.

Ky.

Japan was very fussy about India and was insisting to sign nuclear treaty. See what they have to say to the world. good that USA has no more nuclear reactor in last 20 years.

Best thing will be to use solar, wind, Hydal and perhaps coal.

During power generation a typical reactor will generate 3 GW (= 1 million Kilowatt) thermal power that is converted to 1 GW electrical power.

If shut down or "spent" the after-heat is down a factor of near 1000 or some MW at beginning from radioactive decay - thus declining with time. At this level the "spent" fuel rods need active cooling beneath water to stay at acceptable and safe temperature.

The "spent" fuel has a lot of useful fuel inside that can be used if reprocessed.

But reprocessing is very expensive and a big risk in itself. I know about accidents in the early phase of nuclear energy development from the first 4 to build nuclear weapons. The 5th to 8th (China, Israel, India, Pakistan) seem to have done better or learned their lessons or I did miss the information about accidents.

The "spent" fuel rods cannot be used further as many of the fission products act as reactor-poisons (= neutron capturers).

In total I am pleading towards future use of the CANDU-principle. (see AECL.com)

It is much safer, makes much better usage of the fuel, can be operated with thorium, does not need shutdown at fuel-rod replacement, but has the big disadvantage of not being invented by one of the big 4 or 5.

More information from the proceedings of ICENES conferences.

RHABE

Isn't pleading for any principle going to be moot at this point as the Japanese incident show how susceptible nuclear power (even new technologies such as the Japanese used) are to unaccounted for normally minor incidents leading to a nuclear disaster. Yes their plant was designed to withstand an earth quake of substantial proportion, and withstood the 9 magnitude earthquake. What they forgot was to protect the secondary power systems that were required to operate if main power went offline against possible flooding from a tsunami. The nuclear facilities weather the tsunami fine, but with out power you get the problem you now see. I perceive that nuclear power is going to be buried again for a number of years due to this current accident in Japan. It would probably make better sense for those in the industry of promoting, selling, and developing nuclear power facilities to start looking elsewhere for employment opportunities for the near future (or become friendlyier with dictatorships seeking nuclear weapons, much like the French have done in the past).

Yes and no:

if such an easy task, to provide power and or cooling cannot be met by a highly qualified engineering team, also in a situation when anything around is devastated then you are right: forget nuclear power. But forget also any other demanding technology.

Japanese were once the technological leaders. So what happened to them? Did they never learn how to improvise? I don't know.

But I do know that the real damage was done by the tsunami. Compared to this the damage by broken reactors (up to this moment) is minimal. And broken does not include until now a broken pressure vessel.

I have no doubt that France will stay and Japan too with nuclear electricity and China without any doubt too.

So let the engineers do a better job next time. That is designing a cooling possibility for after-heat removal from used fuel rods and shutdown reactors that is not requiring energy but is running by itself.

Or make the emergency cooling systems triple redundant - what is now mandatory in Germany.

Steam boilers claimed a lot of victims until the now existing codes were written!

The same - but less victims - will be true for nuclear steamers.

RHABE

The thing is this, which you seem to have over looked, other energy technologies go offline when their is a disaster that adversely imapcts them to failure. You may get some localized pollution of resources. Nuclear energy fuel systems are not something that shut off, all we do is moderate the energy output from the system to keep it from naturally causing a disaster. It is a control disaster occurring over a very long period of time, thus mitigating damage. When we lose control it accelerates. We lose control on a coal fired plant and the plant shuts down and the energy generation systems stop operating, the coal doesn't burn out of control and accelerate the amount of uncontrolled energy being released. The management of the fuel source is just simpler.

But what if a tsunami hit one?

if a tsunami flooded out a coal fired plant, are you suspecting the fuel would start burning as it was flooded by a tsunami or that the power generation engine (coal burners) would start to run away and spiral out of control because a back up generator went off line? And lets say that some how a coal fired plant spirals out of control, what are the consequences?

Aside from the ones mentioned - I imagine the tailing heaps might be washed away.

And as you know, this is extraordinarily toxic material including some interesting isotopes, now spread far and wide over the landscape, water system, agricultural system, and the balance dragged out to fisheries.

The other factor of 'why not use coal?" is Japan doesn't have enough left.

It's "finite" as they say.

Extraordinarily toxic might be an exaggeration for solid coal, though it does contain some toxins. If it were that toxic major sections of the central and eastern US and most of england would be unlivable. The dust and smoke can be problematic due to the carcinogens and the increased susceptibility due to inhalation exposure. Coal is actually formed under shallow seas. Plus I suspect it would not move to far before it started to settle out when the water velocities dropped. So you would end up within a relatively small areas that the fairly large pieces of solid coal were spread across on the surface of land or shallow sea bed. In this respect coal might be safer than petroleum, which would intersperse through out the water column and float long distances. Admitedly, however natural gas might be the safest in this sense of the common energy sources.

Well I did say tailings.

And there is the volume problem. Someone mentioned the mass and yield ratio - here or similar Japan topic thread.

Sue posted this today - the link to the graphic might help with 'scale' on this.

I would not want to be working in the vicinity of a supercritical boiler in a power plant if it got hit by a tsunami. I think that the debris field would be quite extensive. And once a coal heap catches fire there can be hell to pay.

There seems to be a general consensus that more redundancy of back-up cooling was needed. But then why not simply outlaw any nuclear facility too close to the shoreline where the possibility of a tsunami exists?

Another issue appears to be that they built too many reactors too close together. Most nuclear facilities especially here in the USA end up having multiple reactors on one site due to NRC licensing difficulties. It's easier to add another reactor to a site once they have gone through the whole process than to come up with a new site and go through the process for it.

Maybe we should just ration electricity, rich man, poor man, apartment or house, tent or trailer we all just get 800 kwh per month. Once you exceed the allotment- click. We would of course have to make adjustments for the colder areas so people will not freeze to death. For the warmer climates, well I never heard of anyone sweating to death so we can reduce their allotment somewhat to make up the difference. People who need less can sell off some or all of their allotment to others who need or want more, sort of like the "Cap & Trade". Then we can just take ALL of the Nuclear facilities off line and not have to be concerned about any accidents, earthquakes, tsunamis etc. except to keep the spent rods cool enough for the next 30 or 40 years or whatever it takes.

or do like they do at Diablo here in california and have it located in a elevated locations on a solid mass of granite. cutting the facilities into a hillside 100 feet or more above the sea level is not a bad idea, out of any flood channels and above the 1000 year flood stage. though it sounds good in a place where we have numerous locations suitable for that, but it is probably not going to happen in places like Bangladesh or Florida, where there is no where above 100 above sea level, and obviously those places want the energy for themselves also.

You are absolutely right with this statements!

So I searched for not so critical reactor designs that enable much safer handling.

This I did some years ago but the result has not changed.

These are the successors of the Canadian CANDU reactor - details at AECL.com

Detailed information is available at the ICENES conferences proceedings - many international experts meet there to debate the future of nuclear energy, and those that are not bound to the big four nuclear-power-plant companies mostly agree that the CANDU principle allows pathways towards much higher safety including shortening of storage time of highly active "waste" from 300,000 years to 3,000years.

The CANDU has small diameter fuel rods that can be stored in the cooling pond at much greater distances and thus with natural convection cooling.

Whereas the other known water cooled reactors have multiple rods (144?) bundled in fuel-elements so heat extraction is much more difficult.

The problem of replacing the water that is boiled away would be existing in the CANDU-type reactors too, but where is the problem of designing bigger cooling ponds? And better emergency systems.

I have no understanding for the Japanese operators that they cannot organise a pump in a few days - near 50 Liter/second would be great. Any ship has these, the firefighters have these, their own power-plant has these (without power because no diesel nor electricity), but I am sure that there is ample diesel fuel in 300km around to be flown in by the military within hours. And also some motor driven generators to provide on-site electricity. So what is going on here?

RHABE

Excuse me please the AECL URL was wrong:

the right one is: www.aecl.ca

http://www.aecl.ca/NewsRoom/Articles/Monitoring_the_Situation_in_Japan.htm

RHABE

In the fission process the uranium atoms split, producing fission products along with the heat. Some of these fission products are poisons (they suck up neutrons) to the nuclear reaction, thus stopping it. So replacement (new) fuel is required; and the used fuel must be stored. Of course reprocessing of the fuel would relieve this storage problem, but fear has stopped it.

"Fear has stopped it" (reprocessing)

Not only fear but also nuclear weapons nonproliferation politics

and first of first cost.

Reprocessing is awfully expensive, so new fuel is much cheaper and with much lower risk, as the spent fuel is loaded with very ugly highly radioactive elements. Better let those be reprocessed in 300 years or so when part of the fast decaying radioactivity is gone.

Or never, because uranium (and thorium) is abundant.

If you look at the "problems" = accidents with release of radioactivity that happened in All(?) reprocessing plants at Hanford, Windscale - Sellafield, La Hague and Soviet Union it becomes clear that reprocessing has its own big risks.

So let it sleep until we may need it. Past and existing reprocessing plants were primarily motivated by weapons-grade plutonium extraction.

RHABE

According to CNN the spent rods were stored on-site in reactor #4 building outside the containment structure in a cooling/holding pond and that is a problem. Although #4 reactor wasn't on-line at the time the cause of a fire in #4 is believed to be a result of the spent rods losing their cooling source and perhaps becoming uncovered. Evidently there is enough power left in them to create a severe problems if the holding tank runs dry and they are left uncovered.