How hot is fuel

[atomicarcheologist]

How long will spent fuel continue to have enough thermal heat to ignite a match by contact?

[GLW]

How long will spent fuel continue to have enough thermal heat to ignite a match by contact?

depends,...

who is holding the match?!?!?!

[RDTroja]

Damn. You beat me to it.

Do the matches work underwater?

[atomicarcheologist]

Damn. You beat me to it.

Do the matches work underwater?

Underwater is out of the equation. Theoretical reach rods are in.

[Marlin]

   The temperature needed to ignite a match is 446 degrees Fahrenheit but the time to drop below that is dependent on fuel design and power history so unless there are a few assumptions tough to say. But since the bundle will not be taken out of the water for dry storage until it is well below that I suspect I am taking the bait so reel me in.

[Marlin]

   The temperature needed to ignite a match is 446 degrees Fahrenheit but the time to drop below that is dependent on fuel design and power history so unless there are a few assumptions tough to say. But since the bundle will not be taken out of the water for dry storage until it is well below that I suspect I am taking the bait so reel me in.

Wow, three answers while I was typing much better than average response. Nice post     

[atomicarcheologist]

   The temperature needed to ignite a match is 446 degrees Fahrenheit but the time to drop below that is dependent on fuel design and power history so unless there are a few assumptions tough to say. But since the bundle will not be taken out of the water for dry storage until it is well below that I suspect I am taking the bait so reel me in.

Not caring whether you need to take the fuel out of the water or unbutton the cask, US commercial fuel is applicable.

[RDTroja]

Underwater is out of the equation. Theoretical reach rods are in.

If it is not underwater I think it will take a long time to cool down... and it likely won't resemble a fuel bundle anymore.

[ipregen]

That's almost like asking how long it takes to bake tollhouse cookies in the pressurizer doghouse.

[Marlin]

If it is not underwater I think it will take a long time to cool down... and it likely won't resemble a fuel bundle anymore.

    I think he is proposing a puzzle that we use to do in the Navy. Find an answer to a question that required you to set your own parameters/assumptions. Such as what dose rate would it take to lift an average size man one foot. We started with the fact that an erg is the amount of energy it would take to lift an average sized mosquito one centimeter and continued to make assumptions that could be vaguely supported within reason.
   With all of the variables in decay heat there is no one answer but I would assume you would look at the residual power in megawatts and temperature generated by that equivalent tracking that to the point that the surface of the bundle would drop below 446 degrees Fahrenheit of an average bundle. State assumptions and justify.

"That's just my opinion, I could be wrong" D.M.

[Rennhack]

That's almost like asking how long it takes to bake tollhouse cookies in the pressurizer doghouse.

3 hours.

[atomicarcheologist]

    I think he is proposing a puzzle that we use to do in the Navy. Find an answer to a question that required you to set your own parameters/assumptions. Such as what dose rate would it take to lift an average size man one foot. We started with the fact that an erg is the amount of energy it would take to lift an average sized mosquito one centimeter and continued to make assumptions that could be vaguely supported within reason.
   With all of the variables in decay heat there is no one answer but I would assume you would look at the residual power in megawatts and temperature generated by that equivalent tracking that to the point that the surface of the bundle would drop below 446 degrees Fahrenheit of an average bundle. State assumptions and justify.

"That's just my opinion, I could be wrong" D.M.

That is correct.

[RDTroja]

    I think he is proposing a puzzle that we use to do in the Navy. Find an answer to a question that required you to set your own parameters/assumptions. Such as what dose rate would it take to lift an average size man one foot. We started with the fact that an erg is the amount of energy it would take to lift an average sized mosquito one centimeter and continued to make assumptions that could be vaguely supported within reason.
   With all of the variables in decay heat there is no one answer but I would assume you would look at the residual power in megawatts and temperature generated by that equivalent tracking that to the point that the surface of the bundle would drop below 446 degrees Fahrenheit of an average bundle. State assumptions and justify.

"That's just my opinion, I could be wrong" D.M.

Yes, I was aware of that... I was just playing the game. I used to play games a little like that when I was teaching RP Initial training classes.

[Marlin]

Yes, I was aware of that... I was just playing the game. I used to play games a little like that when I was teaching RP Initial training classes.

I should have know that anyone who could smell radiation would know that. 


   That is not a demeaning statement, Roger and I were walking down a hallway in an auxiliary building (decades ago) when he said he could smell radiation. I was a little incredulous at first but there was a scent unique to the containment at power we could smell and as it turned out there was a small amount of airborne due to an odd line up by OPS.

[RDTroja]

I will never live that particular choice of phrasing down, will I?

[atomicarcheologist]

   The temperature needed to ignite a match is 446 degrees Fahrenheit but the time to drop below that is dependent on fuel design and power history so unless there are a few assumptions tough to say. But since the bundle will not be taken out of the water for dry storage until it is well below that I suspect I am taking the bait so reel me in.

So the time frame at the average commercial reactor for it's spent fuel to cool below the 446 F is 7-20 years? Can anybody dial that in a bit more precise?