ORIGEN calculation without depleting starting material

[Chad Denbrock]

Hi all,

I am trying to run a simple, conservative activation calculation where I irradiate my given material for a long time. This long time happens to deplete the starting material considerably. My goal is to run the calculation unphysically in a way that the starting material maintains its initial mass and composition. I have tried a number of methods to approximate this scenario:

1. Breaking my full irradiation into smaller cases and instantiating the initial material again in the new irradiation case using the mat {iso = [...]} card
   1. This results in ORIGEN giving unphysical results in a way I do not understand what ORIGEN is doing with my new material.
2. Breaking my full irradiation into smaller cases and instantiating the initial material again in the new irradiation case using the mat {previous = 0} card
   1. This results in a fatal error
3. Breaking my full irradiation into smaller cases and instantiating the initial material again in the new irradiation case using the mat {load [file = "....f71" position = 0} card
   1. It appears ORIGEN ignores this option for me

My two questions are:

1. Is there an option in ORIGEN to simply set the gain/loss terms in the transition matrix to 0 for my initial material?
   1. If not, what other options do I have to approximate a no depletion irradiation?

I am running ORIGEN from SCALE6.2.3.

Thanks in advance!

Chad

[Pavlo Ivanusa]

You can use the feed array option and make up the portion that is lost. You'll have to likely do some iterating here to make sure you're replenishing as quickly as your losing.

[Chad Denbrock]

Pavlo,

Yes I successfully used the feed option for a single isotope in my mixture. The problem is I am running activation analysis on impurities for a bunch of materials. That would force me to calculate feed rates for hundreds of cases, something I would prefer not to do.

[Pavlo Ivanusa]

Another option is to try to use COUPLE to modify the transition matrices, but that might take up a lot of time. At that point, it might be easier to use an external script to run a short depletion, extract out the materials you want to retain using something like OPUS (or f71tocsv), and then run another case with the same material masses that you want to keep constant along with the material masses from your depletion case. Iterate that way until you have a long enough depletion. 

The problem is, like you said, you're trying to use ORIGEN in a very non-physical way, so it's going to require a good deal of work to circumvent that. 

[Chad Denbrock]

Thanks Pavlo.

It seems like ORIGEN may not be the appropriate tool for what I am looking to do.

[Alfonso Barbas Espa]

Did you try a first case with your initial material and really low cutoff and dt and then using the results as a feed in a fresh simulation without initial material at all?

Alfonso.