High Rate Calculation
At higher burn rates, additional coolant is required to be buffered in coolant pipes between the reactor and the boiler or turbine (if water cooled). Theoretically there should be math to figure this out but no one seems to know it.
My theory is that at higher rates, at any given tick, less and less cooled coolant is present in the reactor. This mathematically becomes a problem for sodium cooling due to the 10x higher heating rate than with water. What can happen is that there is not enough coolant left in the reactor since at any given tick it has to be in one of many places, and if its all been heated out of the cooled coolant tank of the reactor then there is nothing left to dissipate heat from the core. So lets find out what happens in our ticks.
- A tick of the reactor heats cooled coolant from the cooled coolant tank into the heated coolant tank
- A tick of a boiler moves coolant from its heated coolant tank to its cooled coolant tank
- A tick of a turbine is similar to the boiler in that it moves coolant as steam from its gas tank into water in its vent tank
Since in a sodium cooled reactor the boiler-turbine loop is separate from the reactor-boiler cooling loop. Therefor only a boiler OR a turbine needs to be accounted for in server ticks of the reactor cooling.
It appears the reactors start losing stability (core temp starts rising with a constant burn rate) after falling below about 27% cooled coolant tank fill. I was not able to get this to occur with a water cooled reactor, which makes sense given the math below showing the destabilizing threshold for water exceeding the max burn of the reactor (see estimated limit for water in the tables). For higher burn rates it just becomes a problem of water being an insufficiently efficient method of cooling so the core temp rises for that other reason.
This design I tested with both sodium and water cooling. The
