The ASME boiler pressure vessel code for nuclear pressure vessels assumes normal and upset operations are always within 100 degF per hour, and that only emergency or faulted conditions exceed that limit. This is part of the vessel stress analysis. There are typically a certain number of pre-analyzed cycles for exceeding these limits, however normal operations keeps you within the limit.Could you elaborate? Is that some nuclear operations aspect of ASME, or simple ASME prohibitions on temperture change rates on metal structures, steam boilers and such? I'm curious as to what rate would apply to molten salt vessels.
For something like LFTR where you have no pressure, it will likely be very different as you don't have steam generation and high pressure.