SEISMIC INSTRUMENTATION

Seismic instrumentation may be installed at nuclear power plants for the 

A seismic interaction is an interaction initiated by an earthqnake that leads to influences between items or between an item and the operator that conld impair their capability to perform their assigned safety function. Interactions may be mechanical (hammering, impact, wear and explosion), chemical (release of toxic or asphyxiant substances), radiological (an increase in dose) or by means of an earthquake induced fire or flood. 

The seismic instruments installed at the nuclear power plant should be cahbrated and maintained in accordance with written maintenance procedures. 

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The seismic instrumentation program (see Section 7.4.3) is consistent with the Regulatory Guide 1.12, Rev. 1, except for the items listed below (Ref. 13)... 

Adequate operational procedures may also contribute to reducing the probability of generating a PIE. Examples include the prevention of excessive thermal stresses in metal pressure vessels and the monitoring of vessel material for radiation embrittlement the limitation of plant transients by the use of pressure relief valves and safety features activated by the protection system prohibitions or restrictions during the conduct of dangerous operations the use of seismic instruments to provide data for the assessment of the condition of the plant for continued operation following an earthquake and the control of... 

A minimum amount of seismic instrumentation should be installed at any nuclear power plant site as follows ... 

The installation of additional seismic instrumentation should be considered for sites having an SL-2 free field acceleration equal to or greater than 0.25g. 

The control room operator should be informed of the occurrence of an earthquake by means of the installed seismic instrumentation. Subsequent responses should include an evaluation of recorded earthquake motion in comparison with the specific design of safety related items, a walkdown evaluation of the damage to the plant and an evaluation to determine the readiness of the plant for the resumption (or continuation) of operation following the occurrence of an earthquake. 

The PFPWR50 structures, systems and equipment will be designed for high level and low probability seismic events such as a design basis maximum earthquake and a design basis limiting earthquake. Seismic instrumentation is planned in accordance with national and international standards. 

ANS 2.10 Guidelines for retrieval, review, processing and elevation of records obtained from seismic instrumentations... 

ISIDe (2013) Italian seismic instrumental and parametric data-base. 

Albuquerque Seismological Laboratory (2001) Specifications for seismic instrumentation boreholes. Retrieved 1 Dec 2013, from U.S. Geological Survey http //earthquake.usgs.gov/regional/asl/pubs/files/tech boreholes.pdf... 

Richter compared earthquake records in Southern Cafifomia made at different distances and azimuths fmm the earthquake source with a standard type of short-period horizontal component Wcx)d-Anderson (W A) torsion seismometer. All these instruments had an identical frequency response (see red curve in Fig. 3 and Seismic Instrument Response, Correction for) and a static magnificariem, according to the manufacturer, of 2800. Many stations of the Southern Califomia seismic network had already in the early 1930s been equipped with such seismometers. Figure 1 shows cm top a typical WA-record of a near... 

Seismic Instrument Response, Correction for) but with a static magnification of 1 (as in Fig. 8), and R = hypocentral distance (see Earthquake Location) in km, typically less than 1,(X)0 km. The constant term in (1), —2.09, is based on an experimentally determined average static magnification of the WA seismograph of 2080 (Uhrhammer and Collins 1990) and aims at making reported Ml amplitude data unaffected by its uncertainty (Bormann and Dewey 2012). 

To better understand the descriptions of seismic instruments, some basic theoretical aspects will be described here. For more details, see e.g., Wielandt 2009 or Havskov and Alguacil 2010. 

Since early times, there was an interest in measuring vibrations of buddings and other constructions, and attempts were made to use seismic instruments for that purpose. It is possible to give... 

Ferrari G (ed) (1992) Two hundred years of seismic instruments in Italy 1731-1940. SGA Storia- Geofisica-Ambiente, Bologna, p 156... 

Seismic instrumentation in Greece was gradually upgraded to obtain its present-day configuration which counts 200+ broadband sensors in operation. The funding to the Greek seismological... 

Seismic Instrument Response, Correction for, Fig.1 The input is the ground moving with a maximum displacement 0.02 mm. This signal goes through an... 

Seismic Instrument Response, Correction for. Fig. 2 RC low-pass filter. R is the resistor and C the capacitor. Input is x(f) and output y(f)... 

Seismic Instrument Response, Correction for. Fig. 4 Amplitude and phase response of an RC filter with a comer frequency of 1 Hz. The phase response (or phase shift) is given in degrees... 

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