核电厂地震仪表记录的处理和初次评估规范

ANSO/ANS-2.10-2003

criteria for the handling and initial evaluation of records from nuclear power plant seismic instrumentation

核电厂地震仪表记录的处理和初次评估规范

Copyright American Nuclear Society

Provided by IHS under license with ANS

No reproduction or networking permitted without license from IHS Not for Resale

Copyright American Nuclear Society

Provided by IHS under license with ANS

No reproduction or networking permitted without license from IHS Not for Resale

ANSUANS-2.1 0-2003

American National Standard

Criteria for the Handling and Initial

Evaluation of Records from Nuclear

Power Plant Seismic Instrumentation

Page

1 Scope (1)

2

Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

3

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

4 Earthquake Evaluation Levels (2)

4.1 Level1 (2)

4.2 Level2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

5 Data Retrieval and Evaluation (2)

5.1 Instrument Characteristics and Status (2)

5.2 Data Retrieval (4)

5.3 Transmission of Data from the Site (5)

5.4 Data Reduction .................................................

5.5 Data Evaluation (5)

5

6 References (6)

Figure

Figure 1 Flowchart for Level 1 evaluation (3)

3 Definitions定义

acceleration sensor加速度传感器: An instrument capable

of sensing absolute acceleration and producing

a signal that can be transmitted to a recorder.

Accelerogram加速度计: The record of acceleration versus

time for a single component of motion.

cumulative absolute velocity 累计绝对速度(CAV: The

time integral of absolute acceleration over the

duration of the strong shaking associated with

an earthquake. This quantity has been shown

to be a good indicator of the damage potential

of an earthquake time history.

design-bases response spectra (DBRS): Response

spectra used to design Seismic Category

I structures, systems, and components.

first-order correction一阶校正: An analytical process

that removes a linearly accumulating error from

an accelerogram.

’

free-field: A ground surface location for an

earthquake motion sensor where the motion

will be only of the ground surface and where

the effects that are associated with certain surface

features, buildings, and components will

be insignificant.

operating-basis earthquake ground mo tion

(OBE): 运行时地震动The vibratory ground motion for

which those features of the nuclear power plant

necessary for continued operation without undue

risk to the health and safety of the public

will remain functional. The OBE is only associated

with plant shutdown and inspection after

an earthquake unless specifically selected

by the applicant as a design input. For the

purposes of this standard, if an OBE analysis

is not part of the licensing basis, the OBE is

defined as one-third safe shutdown earthquake

ground motion (SSEj or lower.

recorded data: The registered output from a

time-history accelerograph (T/Aj.

seismic data retrieval: The process of collection, identification, and preservation of all re i)

Numbers in brackets refer to corresponding numbers in Section 6, “References.”

American National Standard ANSI/ANS-2.10-2003

corded data and pertinent observations relating

to a seismic event (earthquake).

seismic trigger: A device that starts the timehistory

accelerograph (T/A) after a preset acceleration

has been exceeded.

shall, should, and may: The word “shall” is

used to denote a requirement; the word “should”

is used to denote a recommendation; and the

word “may” is used to denote permission, neither

a requirement nor recommendation.

time-history accelerograph (TIA): An instrument

capable of sensing and permanently re cording

acceleration versus time.

zero-order correction: An analytical process

that removes a constant error, such as a base

voltage, from T/A data.

4 Earthquake Evaluation Levels地震评估等级

The licensee of a nuclear power plant shall take

appropriate action (specific activities) to determine

whether the plant OBE has been exceeded

after an event that activates the seismic instrumentation

and was identified as an earthquake

by a majority of control room operators on duty

at the time. The specific activities will begin and

will continue unless it is verified by additional

instrumentation and other confirmation that an

earthquake has not occurred. The specific activities

to be taken along with the sequence of occurrence

are shown (with the sections of this

standard that describe them) graphically in Figure

1. There are two levels of seismic data evaluation;

these are described below.

4.1 Level 1

Level 1 comprises the initial evaluation to determine

whether measurements received from

the seismic instrumentation indicate that the

OBE has been exceeded. This evaluation is covered

in this standard and shall be completed

within 4 hours of the earthquake.

This evaluation shall be accomplished automatically

through the use of software contained

within the accelerometer or a remote computer linked to the accelerometer, or manually by

staff personnel who directly evaluate the timehistory data on the site or at some remote location;

see 5.5.2.

4.2 Level 2

Level 2 constitutes an evaluation of all accessible data recorded by seismic instrumentation.

The Level 2 evaluation is addressed in

ANSI/ANS-2.23-2002 [2]. This evaluation will typically be more detailed than a Level 1 evaluation. For example, more instruments and more damping values and response frequencies will

be available for evaluation.

5 Data Retrieval and Evaluation

This section sets forth activities required for

the Level 1 evaluation described in Section 4.

5.1 Instrument Characteristics

and Status

5.1.1 Documentation of Plant Instrumentation Characteristics

A record of all seismic instrumentation shall be kept on file at the plant. The file shall contain

the following information for each instrument

as applicable:

(1) make, model, and serial number;

(2) manufacturer’s data sheet;

(3) list of special features or options;

(4) performance characteristics;

(5) examples of typical instrumentation readings and interpretations;

(6) operations and maintenance manual;

(7) repair procedures (such as manufactur er’s recommendations for repairing common problems);

(8) list of any special requirements, such as

those related to maintenance, operation, or installation;

(9) location and orientation of instrument.

The location of each instrument and the orientation of the instrument axes with respect

to the plant reference axes shall be recorded.

The record shall include appropriate building

and equipment plan views and vertical

sections. A description of the access to instruments

that require manual data removal shall

be included;

(10) all records of recorded earthquakes and

instrumentation characteristics should be retained

for the life of the plant.

2

American National Standard ANSI/ANS-2.10-2003

I Compare earthquake

against OBE (Level l),

Section 5.5.2

Maintain seismic instrumentation

defined in ANSVANS-2.2-2002

I

Earthquake occurs, Section 4

Retrieve and analyze

data (Level l)S,e ction 4.1

1"" I

Section 5.5.2.5

passes response

spectrum criteria?

Section 5.5.2.3

I I OBE is exceeded, I

Section 5.5.2.5

Operability check, Operability check,

See ANSVANS-2.23-2002

Figure 1 - Flowchart for Level 1 evaluation

O hour

4 hours

5.1.2 Operational Status (2) name of the technician who performed

A complete service history of each seismic instrument

shall be kept on file at the plant. The

service history shall contain the following:

the servicing;

(3) operational status, including notes of

anything unusual in instrument installation

(e.g., high background noise or changing of gain);

(1) dates of servicing and a record of the

time out of service for each repair;

3

American National Standard ANSI/ANS-2.10-2003 (4) calibration records and associated data (where applicable). After initial installation

and each servicing of the free-field instrument,

a response spectrum and CAV shall be calculated and filed. A suitable earthquake

time history (e.g., the October 1987 Whittier, California, earthquake) or manufacturer’s calibration standard shall be used;

(5) recommendations for follow-up work and completed work.

5.2 Data Retrieval

5.2.1 General

(1) Data collection from seismic instrumentation shall be undertaken by only those

trained to prevent loss of data.

(2) Caution shall be exercised to prevent ac cidental damage to the recording media (disc,

memory card, etc.) and instruments during

data collection and subsequent handling.

(3) Caution shall be exercised to prevent ac cidental erasing of the data from instrument

memory. Before data are deleted from instrument memory, two copies shall be made on

separate recording media.

(4) For validation of collected data, a postevent calibration or reference signal shall be

added to the record before removing the recording media.

(5) As each record is collected, the condition

of the instrument shall be documented. The inspection shall assess whether any of the following conditions (and any similar situations) exist: instrument flooded, mounting surface

tilted, and fallen objects that might have

struck the instrument or instrument mounting surface. Sketches or photographs, or both,

should be used to help clariSr the description. (6) A record collection log that contains the information listed in 5.2.2, 5.2.3, and 5.2.4

shall be maintained at the plant.

(7) After data retrieval and making any necessary repairs or calibration to the instruments,

the instruments shall be restored to

active status.

Where instrument operation appears to have

been in accordance with the design, the instrument shall be placed back in service without

making any readjustment or modification

that would prevent making a postevent calibration.

Where an instrument appears to have changed

its characteristics, been damaged, or made inoperable in any way, the transfer function,

volts per units of gravity (g) or millimeters

per g, should be measured without making

any readjustment. This measurement shall

be performed using applicable procedures such

as those prepared in accordance with the instrument manufacturer recommendations.

(8) Data from inaccessible recorders shall be collected as soon as access becomes feasible.

If plant shutdown is required for access and immediate shutdown does not occur, data from

the inaccessible recorders shall be collected during the next outage.

5.2.2 Data Identification

All data shall be identifiable and traceable with respect to the following:

(1) date and time of triggering earthquake

and collection;

(2) make, model, serial number, location, and orientation of the instrument from which the record was collected;

(3) identification of the individual performing data collection.

5.2.3 Record Preparation

Record preparation shall include the following:

(1) Labeling: All records shall be labeled as

to axis directions and recording scale;

(2) Solid-state records: Records from solidstate recorders shall be analyzed according

to the manufacturer’s s pecifications. Pertinent notations shall be made of any unusual conditions, including the following:

(a) record anomalies;

(b) nonpertinent signals with notes identifying

any apparent causes.

5.2.4 Immediate Data Logging

Immediate (within 4 hours) data logging shall include the following information:

(1) seismic trigger annunciation;

(2) CAV values from free-field record;

4

American National Standard ANSI/ANS-3.10-2003 (3) response spectrum values from free-field records;

(4) any exceedance of the OBE.

5.3

Prior to the removal of any original data records from the site,

Transmission of Data from the Site

(1) copies of visual data shall be made using photocopy or other techniques;

(2) data on any magnetic or electronic media

shall be duplicated; a visual record (photo process) may be used. This duplication should

be completed as soon as possible and before

the data are analyzed;

(3) a log of transmitted data shall be added

to the record log described in 5.2.1(7).

5.4 Data Reduction

5.4.1 Engineering Units

Acceleration records shall be converted to units

of acceleration (such as g’s or centimeters per second per second). During this procedure, obvious discrepancies among different channels

shall be noted (e.g., one channel did not record

the earthquake).

5.4.2 Data Processing

Processing includes baseline correction of accelerograms and other analytical corrections that

extend the useful frequency range of the data.

The processing of data from each instrument

shall include the following actions:

(1) each accelerogram shall be digitized at

equal time intervals of not greater than 0.005 seconds;

(2) the start of each digital accelerogram shall

be clearly identified, and a common initial

time shall be established;

(3) each digital accelerogram shall be “corrected.”

For example, the effect of the following

items shall be addressed:

(c) acceleration sensor natural frequency

(d) instrument transients recorded during

(e) presence of data outside the instru-

(f) any constant (zero-order) or accumulatand damping (instrument correction);

instrument start-up;

ment frequency range;

ing (first-order) errors;

(4) each acceleration sensor’s sensitivity shall

be applied to its corresponding digital accelerogram such that the reported accelerogram

amplitude values are in units of gravity (g).

5.5 Data Evaluation

5.5.1 Summary of Data

All reduced data shall be tabulated with respect

to instrument type, location, and axes

orientation:

(1) Erne-history acceleration: The maximum

peak value shall be determined. The predominant frequency (as determined by inspection),

if any, shall be estimated. The duration

of strong motion (time between first and last observation of excursions containing accelerations greater than or equal to 0.025 g) shall

be estimated;

(2) Response spectrum: The acceleration and

velocity response spectra shall be plotted using

5% damping and the same amplitude frequency

scale as was used for the OBE DBRS

(which is the comparative response spectrum

that is to be used to compare with the spec tra from the free-field instrument recordings);

(3) Cumulative absolute velocity: The CAV values for each component shall be noted.

5.5.2 Operational Requirements for Determining If the OBE Was Exceeded

5.5.2.1 General

The Level 1 evaluation shall be performed on

the three free-field surface components (i.e.,

two horizontal and one vertical). Instrument corrections shall be made as necessary. The evaluation may be conservatively performed on earthquake records having no baseline corrections [3]. The evaluation shall consist of a CAV

check and a response spectrum check. Exceedance criteria are defined for the CAV check

and the response spectrum check in 5.5.2.2 and 5.5.2.3.

5.5.2.2 CAV check

The motions’ CAV values shall be computed

and compared to 0.16 g-second. If any one of

the three component values (two horizontal and one vertical) is larger than 0.16 g-second, the CAV criterion shall be deemed to be exceeded. The CAV value has been shown in Ref. 4 to be

a reliable lower-bound indicator that an earth-

5

American National Standard ANSI/ANS-2.10-2003 quake could cause damage at a specific location. The CAV may be determined analytically

from an acceleration time history or by means

of a mechanical or electrical device.

The determination of the 0.16 g-second value is described in Ref. 3. The calculation of the CAV shall be as follows:

(1) for each acceleration component time history, the absolute acceleration (g units) time

history is segmented into 1-second intervals; (2) for each acceleration component time his tory, each 1-second interval that has at least

one exceedance of 0.025 g is integrated over time;

(3) for each acceleration component time history,

all the integrated values are summed

together to arrive at the CAV.

5.5.2.3 Response Spectrum Check

The response spectrum check is performed using the lower of the spectrum used in the certified standard design, or another spectrum used in

the design of any Seismic Category I structure.

If an OBE analysis is not part of the licensing basis, one-third SSE or less shall be used.

The response spectrum criterion shall be deemed

to be exceeded if any one of the three components’(two horizontal and one vertical) 5%

damped free-field surface motion response spec tra is larger than

(1) the corresponding design response spectral acceleration (see above) or 0.2 g, whichever

is greater, for frequencies between 2

hertz to 10 hertz inclusive

or

(2) the corresponding design response spec tral velocity (see above) or a spectral velocity

of 6 inches per second (15.24 centimeters per second), whichever is greater, for frequencies between 1 hertz and 2 hertz. The 1-hertz

limit shall be reduced, if necessary, to include

the lowest Seismic Category I building fundamental frequency.

5.5.2.4 Numerical Analysis Determination

The response spectrum check shall be considered exceeded if one spectral ordinate from any

of the three components (two horizontal and

one vertical) exceeds the criterion value. Oscillators, at O. 1-hertz intervals, shall have their

responses evaluated.

5.5.2.5 OBE Exceedance

If the response spectrum criterion and the CAV criterion are exceeded in any component, then

the earthquake motion has exceeded the OBE.

If either criterion is not exceeded, the earthquake motion did not exceed the OBE. If only

one check (CAV or response spectrum) can be performed, the other shall be presumed to be exceeded. Figure 1 summarizes the recommended detailed requirements for a Level 1

OBE exceedance evaluation.

5.5.3 Operability Check

After an earthquake and the evaluations of

5.5.2 have been run, the response spectra and

CAV analysis of a standard earthquake [5.1.2(4)] shall be conducted to demonstrate that the system software functioned properly.

5.5.4 Timing

The evaluations described in 5.5.2 shall be completed within 4 hours of an earthquake

occurrence.

6 References

American National Standard, “Earthquake Instrumentation Criteria for Nuclear

Power Plants,” ANSI/ANS-2.2-2002,

American Nuclear Society, La Grange Park, Illinois.

American National Standard, “Nuclear

Plant Response to an Earthquake,” ANSI/

ANS-2.23-2002, American Nuclear Society,

La Grange Park, Illinois.

“Standardization of the Cumulative Absolute Velocity for Use with EPRI OBE Exceedance Criteria,” TR-100082, Electric

Power Research Institute (1991).

“A Criterion for Determining Exceedance

of the Operating Basis Earthquake,” NP-

5930, Electric Power Research Institute

(July 1988).

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