UFD_DECAY not working with CHEMISTRY

[Tamás Olasz]

Dear Glenn,

I have been using PFLOTRAN version 4 before, and I had no problem running UFD_DECAY and CHEMISTRY together. However, since upgrading to version 5, I get this error message:

"The UFD_DECAY process model may not be used with other reactive transport capability within PFLOTRAN. Minerals (and mineral kinetics) are used because their data structures are leveraged by UFD_DECAY, but no "conventional" mineral precipitation-dissolution capability is used."

Did something change in the code that doesn't allow UFD_DECAY to be ran together with conventional reactive transport calculations? If so, is there a good workaround solution to still simulate the transport of radionuclides (including proper element and isotope based sorption, ingrowth, solubility etc.), and the geochemical calculations such as mineral dissolution-precipitation together?

Thank you in advance,

Tamás

[Hammond, Glenn E]

Tamas,

I will let Sandia developers answer your question before I provide input on possible solutions.

Glenn

From: pflotra...@googlegroups.com <pflotra...@googlegroups.com> on behalf of Tamás Olasz <olat...@gmail.com>
Date: Wednesday, July 2, 2025 at 7:48 AM
To: pflotran-users <pflotra...@googlegroups.com>
Subject: [pflotran-users: 8473] UFD_DECAY not working with CHEMISTRY

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[Hammond, Glenn E]

Tamas,

As we have not heard from the Sandians, I will attempt to answer myself. 

In the past (when I was involved in developing UFD_DECAY), the capability leveraged data structures that were used by the conventional reactive transport capability in PFLOTRAN, in particular, the sorbed concentrations and mineral volume fractions. UFD_DECAY overwrites what is calculated by dummy mineral reactions. Therefore, you could not run both (i.e., conventional reactive transport and UFD_DECAY) at the same time. An error message was added to prevent users from doing so. That error message may not have existed in earlier version.

Glenn

From: pflotra...@googlegroups.com <pflotra...@googlegroups.com> on behalf of Tamás Olasz <olat...@gmail.com>
Date: Wednesday, July 2, 2025 at 7:48 AM
To: pflotran-users <pflotra...@googlegroups.com>
Subject: [pflotran-users: 8473] UFD_DECAY not working with CHEMISTRY

Check twice before you click! This email originated from outside PNNL.

[Tamás Olasz]

Dear Glenn,

thank you for your answer. I understand that UFD_DECAY uses the data structure of the minerals and mineral kinetics that chemistry provides, and there needs to be dummy minerals defined for radionuclides that are used in UFD_DECAY. However, including different minerals and species apart from these to be used in chemical calculations has not been a problem with previous versions of PFLOTRAN (version 4), I ran many models like that and they all ran without a problem (so it is not just an issue of printing an error message or not). But in version 5, the same model simply doesn't run and produces the error message I originally posted. You can find a set of simple input files that I used for testing this here: https://drive.google.com/file/d/1gBgdoI-bOL0C-5UExQPHM8bevJOSsIjo/view?usp=drivesdk

Tamás

[Leone, Rosie]

Tamas,

We've added in a keyword to the master branch of PFLOTRAN that you can put into the WASTE_FORM_GENERAL block to bypass the UFD Decay error:

WASTE_FORM_GENERAL

       ACKNOWLEDGE_CHEMISTRY_CONFLICT

       ....

You'll have to pull the latest version of master, let me know if this doesn't work for you.

Rosie

---

From: pflotra...@googlegroups.com <pflotra...@googlegroups.com> on behalf of Tamás Olasz <olat...@gmail.com>

Sent: Thursday, July 10, 2025 1:19 AM
To: pflotran-users <pflotra...@googlegroups.com>
Subject: [EXTERNAL] Re: [pflotran-users: 8496] UFD_DECAY not working with CHEMISTRY

 

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[Tamás Olasz]

Dear Rosie and Glenn,

thank you for your answers and contrubitions. With the option of bypassing this, I made some further testing and it looks like for my purposes the two modules work fine together, so in my understanding UFD_DECAY overwrites those part of the chemistry only that are related to the radionuclides, but the "normal" chemical calculations remain as they are.

Tamás

[Hammond, Glenn E]

Tamas,

You are correct.

By adding the acknowledgement card, we are forcing the user to acknowledge that minerals included in UFD_DECAY cannot be included in "normal" chemical calculations as the rates calculated by "normal" chemical calculations will be overwritten.

Glenn

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