IEEE 344-1987 pdf free.IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power GeneratingStations.
IEEE 344 in this section establish the meanings of words in the context of their use in this recommended practice.See ANSL/IEEE Std 100-1984[1]4 for further definitions.
broadband response spectrum: A response spectrum that describes motion in which amplified response occurs overa wide (broad) range of frequencies.
coherence function:The coherence function defines a comparative relationship between two time histories.lItprovides a statistical estimate of how much two motions are related, as a function of frequency.The numerical rangeis from zero for unrelated, to 1.0 for related motions.
correlation coefficient function: The correlation coefficient function defines a comparative relationship between twotime histories. It provides a statistical estimate of how much two motions are related, as a function of time delay.Thenumerical range is from zero for unrelated, to + 1.0 for related motions.
cutoff frequency: The frequency in the response spectrum where the zero period acceleration asymptote begins. Thisis the frequency beyond which the single-degree-of-freedom oscillators exhibit no amplification of motion, andindicate the upper limit of the frequency content of the waveform being analyzed.
damping: An energy dissipation mechanism that reduces the amplification and broadens the vibratory response in theregion of resonance. Damping is usually expressed as a percentage of critical damping.Critical damping is defined asthe least amount of viscous damping that causes a single-degree-of-freedom system to return to its original positionwithout oscillation after initial disturbance.
flexible equipment: Equipment, structures, and components whose lowest resonant frequency is less than the cutofffrequency on the response spectrum
floor acceleration: The acceleration of a particular building floor (or equipment mounting) resulting from the motionof a given earthquake. The maximum floor acceleration is the zero period acceleration(ZPA) of the floor responsespectrum.
Fourier spectrum: A complex valued function that provides amplitude and phase information as a function offrequency for a time domain waveform.
ground acceleration:The acceleration of the ground resulting from the motion of a given earthquake.The maximumground acceleration is the zero period acceleration(ZPA) of the ground response spectrum.
narrowband response spectrum: A response spectrum that describes the motion in which amplified response occursover a limited (narrow) range of frequencies.
natural frequency: The frequency(s) at which a body vibrates due to its own physical characteristics (mass andstiffness) when the body is distorted in a specific direction and then released.
operating basis earthquake(OBE); An earthquake that could reasonably be expected to occur at the plant site duringthe operating life of the plant considering the regional and local geology and seismology and specific characteristics oflocal subsurface material. It is that earthquake that produces the vibratory ground motion for which those features ofthe nuclear power plant, necessary for continued operation without undue risk to the health and safety of the public, aredesigned to remain functional.
power spectral density(PSD): The mean squared amplitude per unit frequency of a waveform.PSD is expressed ing/Hz versus frequency for acceleration waveforms.
qualified life: The period of time, prior to the start of a design basis event (DBE), for which the equipment wasdemonstrated to meet the design requirements for the specified service conditions.IEEE 344 pdf download.