Bulk thermal source in DynamicOnePhaseFlowPipe

In some cases it could be useful to have an additional thermal power source in DynamicOnePhaseFlowPipe (and also other modules: volumes, two phases...) to take into account power sources that come not from the wall but are directly generated within the fluid. It could be for example:

• Because of radiations in the core (~5% of the nuclear power).
• Because of chemical reactions in the fluid.

The module(s) could be easily modified to have a conditional InputReal to inject the needed power, calculated outside the model itself. Another approach could be to have a replaceable model which has zero power by default but that can be replaced with any other model when needed.

I am wondering whether this should be integrated in the std modules or, since it is quite uncommon by the way, specific modules should be developed (to keep the std ones as simple as possible).