Note in the Euronuclear article, it states "
FRMZ,
research reactor of the university of Mayence in Germany, type TRIGA-Mark-II; pulse power 250
MW, permanent power 0.1
MW." Pulses are typically in the 10's of ms (milli-seconds) for looking at 'transient behavior' of nuclear fuel, usually in response to a reactivity accident, which is a 'hypothetical' accident. The 'permanent' of 0.1 MW should be 'steady-state' power. After a pulse/test, the fuel is normally inspected to see if integrity is maintained.
Power reactors operate normally at constant power, although a reactor may 'load-follow'. Power maneuvering may be unrestricted, i.e., no restriction on power ascension (ramp) rates, but normally it's a few %/hr to 10-40%/hr, depending on the conditioning of the fuel. Often, if the fuel mechanical integrity is not limiting, the balance of plant (response of turbine/generator) is limiting. Another concern would be pressure pulses in the cooling system and potential for rupture of the piping or coolant boundary, as well as fatigue of the piping/pressure boundary.
There are technical limits on peak fuel enthalpy (stored energy) and temperature. With about 30% of fission products being isotopes of Xe and Kr (noble gases) with another significant fraction being Br, I, Rb, Cs, which are volatile well below the melting point of UO
2/MOX fuel, the fuel could potentially balloon or rupture is the fuel temperature became too great, especially near the surface of the fuel.
Pulses in 'pulsed' reactor operation are completed well before the longer-lived delayed neutron precursors release neutrons, but on may observe their effect in the 'tail' after the pulse.
Utilities (power reactor operators) do not pulse their power reactors, nor would they plan to do so.