IEEE 344-2004 pdf download IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations
3.5 cutoff frequency: The frequency in the response spectrum where the ZPA asymptote begins. This is thefrequency beyond which the single-degree-of-freedom (SDOF) oscillators exhibit no amplification ofmotion and indicate the upper limit of the irequency content of the wavelorm being analyzed.
3.6 damping: An energy dissipation mechanism that reduces the amplification and broadens the vibratoryresponse in the region of resonance. It is usually expressed as a percentage of critical damping, Criticaldamping is defined as the least amount of viscous damping that causes a SDOF system to return to its original position without oscillation after initial disturbance
3.7 earthquake experience spectrum (EES): The response spectrum that defines the seismic capacity ofareference equipment class based on earthquake experience data.
3.8 flexible equipment: Equipment, structures, and components whose lowest resonant frequency is lessthan the cutoff frequency on the response spectrum.
3.9 floor acceleration: The acceleration of a particular building floor (or equipment mounting) resultingfrom the motion of a given earthquake. The maximum floor acceleration is the ZPA of the floor responsespectrum.
3.10 Fourier spectrum: A complex valued function that provides amplitude and phase information as afunction of frequency for a time domain waveform.
3.11 ground acceleration: The acceleration of the ground resulting from the motion of a given earthquake.
The maximum ground acceleration is the ZPA of the ground response spectrum.
3.12 inclusion rules: The rules that define the bounds of equipment included in a reference equipment classbased on an acceptable range of equipment physical characteristics, dynamic characteristics, and functionsfor which seismic ruggedness has been demonstrated by experience data.
NOTE–See 10.2.3,1 and 10.3.3,1.6
3.13 independent items: Components and equipment that (a) have different physical characteristics or (b)experienced different seismic motion characteristics. c.g.. different carthquakes. diflerent sites. differentbuildings. or different orientations/locations in the same building
3.14 median-centered in-structure response spectrum: In-structure response spectrum developed usingrealistic damping and best estimate modeling paraeters to obtain the most probable structural amplificationthat could realistically occur for the level of the specified earthquake ground motion.
3.15 narrowband response spectrum: A response spectrum that describes the motion in which amplifiedresponse occurs over a limited (narrow) range of frequencies.
3.16 natural frequency: The frequency(s) at which a body vibrates due to its own physical characteristics(mass and stiffness) when the body is distorted in a specific direction and then released.
317 operating basis earthquake (OBE): An earthquake that could reasonably be expected to occur at theplant site during the operating life of the plant considering the regional and local geology and seismologyand specific characteristics of local subsurface material. It is that earthquake that produces the vibratoryground motion for which those features of the nuclear power plant, necessary for continued operation with-out undue risk to the health and safety of the public, are designed to remain functional.
IEEE 344-2004 pdf download
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