Nuclear Heat

It depends on what you think is significant.

Decay Heat.

And it wouldn't really be called geothermal energy (heat).

No. You'd effectively be putting together an uncontrolled reactor, and you could end up with a melt-down.

(And geothermal energy is something different - did you just mean "low grade heat"?).

No! Not, safely.

Don't even think about it.

The cost of the required protective measures would far outweigh any profit to be made.

Yes, it would need a more elaborate name, than geothermal, like "waste-not want-not." It may result in a melt down, but maybe there is a place where that wouldn't matter, and there we could just "let her rip." Do you have an idea of the typical physical dimensions of a spent rod out of a sub, aircraft carrier, or commercial facility?

Let's just say 6 inch diameter by 20 feet. Depends on the application. The actual fuel is pellets 1/4 inch dia. by 12/ inch, or so, placed in the "fuel rods". Name your size, it doesn't matter.

The rods are too DANGEROUS and HEAVY to move safely anyway.

This idea cannot be put into practice. It is TOO DANGEROUS!!!!!!

Thank you Lyn. Do you know of fuel rods that are more narrow and where would I find such information? When they are stored, do they stay in the same wide "Rods?" About how far apart do they store the rods? And how hot do they get in storage?

From Wiki:

Spent nuclear fuel stored underwater and uncapped at the Hanford site in

Do some basic research on the subject.

It's too nasty to fool with unless you have a few million dollars to invest.

Don't go there.

Lyn,

I don't have a few $million to spend, but with less effort it may be possible to show that the spent rods may be used in a way to compare with their initial value. Do modern-day engineers have security clearances that compare to WWII clearances?

Wow! What a great referrence with important contacts! And you do this as a hobby or "relaxer!"

So if you had a truck load of "spent rods", the truck driver would have to be switched every few miles, and an army of traffic cops would have to keep the road clear as the truck sped past? Would the truck have to be sacrificed?

iNFCIS

Nuclear Fuel Cask

AS has been stated, all the energy that can be practically had from fuel rods is already had when the fuel is retired.

If it were practical or purposeful to drill holes in rocks and heat them (the rocks), it would already be in the current practice playbook. The fuel is VERY expensive, and every effort is made to get all the energy that can be had.

Yes, I am sure that all the "practical" energy has been used, but that that is still in the rods producing heat that can be used to liberate additional energy, such as is found in the heavy oil of India may be cheaper than burning oil to make the steam to liberate such a great national resource, AND it may be safer than setting the oil field on fire through insitu combustion!

How far beneath the oil source layer of rock would the rods need to be to minimize radioactive contamination? And would there be a possibility of a super critical mass if the pellets were dumped out of the rods into tighter piles?

This sounds like a determined step towards Armageddon.

John,

We are drilling more but enjoyning it less, due to having to leave so much oil in the ground. We are fissioning more but enjoying it less due to having to store spent fuel rods.

Maybe we can solve both problems with one solution, that is, use the rods to cook the oil, maybe even insitu refining!

If we are smart enough, we can do it safely.

It would be very unlikely. And if you were able to convince someone to do this have them put it in your backyard - not mine!

There are other safer ways to get heat (geothermal, solar) that can be used for energy harvesting.

Fuel rods will be highly radioactive for many generations beyond our life time. This causes the problems that we have of storing, disposing of. The US government spent millions digging a storage facility at Yucca Mountain.

Perhaps the best way to handle spent fuel rods is to reprocess them. The fuel that you get then is better that the new rods were. Presdent Carter singed a presidenal degree to hale all repocessing because he believed that the plutonium from them would get into the hands of terrorist groups

J,

Yes, I am sure you are correct about reprocessing. I am getting tired of regulating my life to suit the terrorists. Maybe, the oil-cooking rods could be retrieved when we start reprocessing.

Ron

Back in the early days of nuclear technology, people used some interesting euphemisms to describe fission and chain reactions. They related it to a dragon. Hopefully the parallel is obvious.

This discussion has reminded me of one of the old terms... tickling the dragon's tail. Intentionally creating a situation where uncontrolled criticality could/would occur might be coined... "poking the dragon".

Sounds fun right?

The advice so far has been dead right... in dragon terms... just let him sleep.

Chaotic,

Well, it is general consensus on this site that we should stay away from further nuclear development! I am just not smart enough to agree with that premise, I can't help feeling that there are many nuclear solutions we have missed.

Once while treasure diving in Desolation Sound, BC, we were warned to stay out of a certain hole due to several fears. At 10 feet down, I was sitting on a ledge peering down into the dark when I decided to float very slowly down. When I landed on the next 10-foot ledge, I found that I could see clearly about as well as on the first ledge, I don't know how to explain the abundant light. Each time, I gained more confidence until I ran out of air hose at 65 feet, on the bottom. There was no treasure, but I had learned to use small steps to over come the fear of the unknown.

And so I feel that pursuing new nuclear uses can be achieved by the same "baby steps," even if it does "tickle and awaken the dragon!"

So I am asking for help in designing an acceptable baby step to stimulate heavy-oil production using spent fuel rods? I have the attention of an international oil service provider.

I too think there is vast room for improvement in nuclear technology. I'm far from anti-nuke, I very much for it.... but in a very controlled and highly engineered environment.

Advancements are being made though and we are light-years from anything remotely close to what you're describing. We are taking those small baby steps. We take what we know, apply it, make mistakes (even though a thousand eyes have scrutinized every detail), learn from them and modify. This process is very slow, almost painstakingly so. But it has to be that way....

I am glad to hear that we are moving forward! I supposed the word "spent" has led me to think of the rods as a near dead dragon.

With a heavy barn broom, my dad killed a mad 1000-pound cow that had attacked him. At the age of 12, I felt pretty brave to get involved once the cow had been "spent." Maybe I am miss judging the rods!

Is your work with spent rods?

Those "spent" fuel rods are infinitely more dangerous than a dead cow.

I am getting curious about how the engineers work with fresh fuel rods. For example, how do they get the fresh rods from the manufacturer down into the ship or reactor?

It seems to me that if they can work with fresh rods, they should have no problem with spent ones. Or do they treat them both with the same respect?

I have never had to deal with spent fuel, but do know about it. I have about 7 years of experience in the nuke industry operating reactors.

Spent fuel doesn't mean the dragon is dead. The easiest way to put it in lay speak is that it means that for a given fuel configuration (speaking about the core geometry here), the reactor can't be "started" anymore (in that particular engineered environment).

It is extremely easy to see the situation you describe resulting in a Chernobyl type accident! I think you would agree it wouldn't be a good thing to have in anyone's backyard.

So the problem is the "engineered environment" or core geometry? You could move the pellets closer together to get the pile to restart? Or leave them farther apart to melt a few billion barrels of heavy oil?

Would the half-life of irradiated oil particles be longer or shorter than that of the rod?

I give up.

I'm with you. I've had enough. <unsubscribe>

That's just it, uncontrolled criticality is pretty ugly, it isn't pretty to imagine in the controlled environment let alone in a non-engineered environment. Plain and simple it is undesirable to get it to "restart" without controls in place.

Once fuel rods are spent, there is no "uncontrolled criticality". That is why they are "spent". They are still highly radioactive and thermally hot - just not hot enough to drive a steam turbine.

Using them as a heat source to drive a thermo-electric generator or perhaps a Stirling engine could allow them to be used in a constructive manner. It isn't without precedent as that is basically what a radioisotope generator does. It isn't highly efficient, at least with current technology, but it does allow the use of waste heat.

Having said that, there is still the difficulty of safely containing the spent fuel rods - but then we already have that problem. We have to safely contain them anyway, why not explore ways of utilizing the heat that is there anyway?

Yes, I think that is what I want, "explore ways of utilizing the heat that is there anyway?" Economically heat heavy oils so that they may be recovered.

Once fuel rods are spent, there is no "uncontrolled criticality".

Two things are obvious from your statement.

1) you've never taken a course on reactor physics and design

2) you didn't even pay enough attention to the news during the crisis in Japan after the earthquake to see your misunderstanding

Try googling it and see where it leads you.

I'll cite you one source ... how about this or this or this or this

I challenge you to cite ONE credible source to back up you claims. Best of luck.

So, you are saying that even inserting, for instance, a generating thermo-electric probe adjacent to the rods or circulating the water from the storage pool through a heat exchanger to drive a Stirling engine is too dangerous to attempt? I never advocated moving them. I never advocated collecting them into a new containment structure. I merely advocate utilizing the heat that is there to do something other than evaporate the water in the storage pool.

Ultimately, they will be moved, though we are going to be arguing about where to for a long time yet. Perhaps current oil and gas drilling technology can be used to put them deep enough that a "meltdown" only gets them to a safer location near the core of the Earth. If they are in a borehole 25000 to 30000 feet down, there is no reasonable chance of them ever contaminating water supplies. With such a technology, they could simply be stored wherever they are currently located with no need to do any transport other than the few hundred yards to the disposal bore. And note that I say "disposal" rather than "storage".

Now this is getting interesting! There is so much to learn about nuclear energy! The referrals from yesterday were fasinating!

So, you are saying that even inserting, for instance, a generating thermo-electric probe adjacent to the rods or circulating the water from the storage pool through a heat exchanger to drive a Stirling engine is too dangerous to attempt?

I was pointing out your conceptual error about spent rods. I've never mentioned anything about inserting probes in a storage pool. Can it be done safely? Absolutely. Is it worth it? I highly doubt it.

There are many brilliant and innovative people working in the nuke field. I haven't run the numbers myself, but my instinct tells me that the reason that the waste heat isn't used in this way is the same reason that photovoltaics aren't installed on every home in the world. Cost vs benefit. The bottom line is that it costs more to buy/own/maintain the system than to just buy the power off the grid.

This isn't to say we shouldn't continue to look at ways to use waste heat. The college I went to was very active in this area. I suspect the best way to use the waste heat would be to use the pool to heat/preheat water for some other process (which some already do).

Back to the original topic of using spent fuel rods... There is enormous capacity still left in them when they are considered "spent". I've often used a gas tank on your car to help people understand it. Imagine filling your vehicle's gas tank to the top. Now you go about your business and as soon as you see the gas gauge move off of "FULL" you dump the tank and refill. That is what spent fuel is, it is not an empty tank but a tank that just moved off of FULL. The common options for what to do with the spent fuel are reprocessing (to ultimately get it back into the reactor) and disposal. There are pros and cons for both. A thought I've had is to design different reactors to use fuels in stages so that the new fuel for the second reactor is the spent from the first, the new for the third is the spent from the second, etc.

Can't the control be the predicted and acceptable end of the life of the pile?

Not wanting to use spent fuel rods in a dangerous maanner, is not the same as not utilizing nuclear fuel, to produce a safe, abundant, alternate to petrochemical fuels.

Solar power, wind power, and geothermal fuels offer some relieve but for the time being can not replace hydrocarbon fuels.

There is a reason to believe that, at least in some cases, geothermal can, and very likely has, produced earthquakes.

J,

Help me understand the dangers of storing the spent rods, 3 miles deep in solid rock, beneath heavy oil deposits. Our state of Utah has been selected to store rods at less depths, and we have annual battles over the issue. It is a shame that something useful can't come from those rods.

Spent fuel rods do put out quite a bit of heat and must be kept cool with circulating water. When there is an outage nuclear plants post time boil. If the water boils away you can have melt down. That is one of the problems in Japans nuclear disator.

Lyn and Wiki,

I am imprresed with your comments and open minds, are you available for consultation and basic research on retainers? May I have your CVs?

Ron 801-400-4529

Sorry Ron,

I have a full time job and 3 small boys to raise. This is just a hobby/relaxer for me.

But, thanks for the offer.

By the way, I lived in Cedar City for 6 months working as a consultant about 10 years ago. I loved it.

Cheers.

What do nuclear engineers consider for an adequate retainer? Take care of those boys; how old are they?

They are 6,7 and 13. Thanks for asking.

Would an engineer be able to calculate the maximum temperature of a big rock, starting at a given temperature, heated by a certain bundle of spent rods?

The constant heat would make a good source for a heat pump. If the heat exchangers were well isolated from the radioactivity, the whole plant could probably be heated forever with that source of energy.

My idea would not require heat exchangers and nor be concerned about isolation. Just "let her rip" to expend most of the precalculated energy.

This would not be that different in principle than the radioisotope generators used for some space probes - and by some radio beacons produced by the former Soviet Union. These used the heat of decay from Plutonium 238 as a long-lasting heat source. Pu238 is used as the radiation emitted is relatively easy to contain. I believe there are some similar devices that use thorium. In truth, most of us have very small radioisotope generators in our homes in the form of smoke detectors. These use americium cells as a portion of the detector.

The biggest difficulties in using spent fuel rods are in transport, containment and getting the public to accept their use. Although they are hot, they are not hot enough to use for efficient steam generation - else they'd still be in the reactor. They could, perhaps, be used in conjunction with a Stirling engine. Technical difficulties can be overcome. I am not so sure about the public perception issue though.