Some RASCAL 4.3 users have experienced this error while attempting to run a case using an imported source term file.
Reason for Error: This error message occurs because the import source term file does not contain all the needed daughter nuclides to support the transport and diffusion modeling. This can occur when during the source term export process you elect to filter out some nuclides.
Error Resolution: There are three ways to resolve this issue:
The easiest fix is to upgrade to RASCAL 4.3.2. That version has an improved source term import function which adds any needed daughters.
Alternatively, if possible, you can repeat the source term export and not use the filter option.
Finally, you can manually edit the file to be imported to add missing daughters. This involves working with the RASCAL documentation of decay chains and should be the method of last resort.