ML20247L311
| ML20247L311 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 03/31/1989 |
| From: | Tuley C WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| Shared Package | |
| ML19302D809 | List: |
| References | |
| WCAP-12230, WCAP-12230-R01, WCAP-12230-R1, NUDOCS 8904050429 | |
| Download: ML20247L311 (86) | |
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s WESTINGHOUSE CLASS.3
- WCAP-12230 l
7-
' WESTINGHOUSE SETPOINT METHODOLOGY FOR PROTECTION SYSTEMS COMANCHE PEAK Unit 1 REVISION 1 March, 1989 C. R. Tuley o
WESTINGHOUSE ELECTRIC CORPORATION Power Systems P. O. Box 355 s
Pittsburgh, Pennsylvania 15230
' ' ~ 8904050429 890331 PDR ADOCK 05000445 PDC A ,
i FOREWORD This document contains material that is proprietary to the Westinghouse Electric Corporation. The proprietary information has been marked by brackets. The basis for marking the information proprietary and the basis on which the information may be withheld from public disclosure is set forth in the affidavit of R. A.
Wiesemann. Pursuant to the provisions of Section 2.790 of the '
Commission's regulations, this affidavit is attached to the application for withholding from public disclosure which accompanies this document.
, This information is for your internal use only and should not be released to any persons or organizations outside the Office of
, Nuclear Reactor Regulation and the ACRS without the prior approval of Westinghouse Electric Corporation. Should it become necessary to obtain such approval, please contact R. A. Wiesemann, Manager, Licensing Programs, Westinghouse Electric Corporation, P.O. Box 355, Pittsburgh, Pennsylvania 15230.
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1 TABLE OF CONTENTS Section Title ' .P_iLqt '
I 1.0- INTRODUCTION 1 I 2.0 COMBINATION OF ERROR COMPONENTS 2 2.1 Methodology 2 2.2 Sensor Allowances 4 2.3 Rack Allowances 6 2.4 Process Allowances ,
7 2.5 Measurement and Test Equipment Accuracy 7 j 3.0 FROTECTION SYSTEMS SETPOINT METHODOLOGY 9 3.1 Margin Calculation 9 3.2 Definitions for Protection System 9
-- Setpoint Tolerances 3.3 Methodology Conclusion 15 4.0 TECHNICAL SPECIFICATION USAGE 52 4.1 Current Use 52 4.2 Westinghouse Setpoint Methodology 53 for STS Setpoints 4.2.1 Rack Allowance 53 4.2.2 Inclusion of "As Measured" 54 Sensor Allowance 4.2.3 Implementation of the 55 l
Westinghouse Setpoint Methodology 4.3 Conclusion 59 Appendix A SAMPLE COMANCHE PEAK SETPOINT TECHNICAL 66
- SPECIFICATIONS I
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. LIST OF TABLES i Table Title Pace l
3-1 Power Range, Neutron Flux - High and Low Setpoints 16 3-2 Power Range, Neutron Flux - High Positive Rate and 17 High Negative Rate 3-3 Intermediate Range, Neutro,n Flux 19 3-4 Source Range, Neutron Flux 20 l 3-5 Overtemperature N-16 21 I 3-6 Overpower N-16 23 i 3-7 Pressurizer Pressure - Low and High, Reactor Trips 25 3-8 Pressurizer Water Level - High 26 3-9 Loss of Flow 27 3-10 Steam Generator Water Level - Low-Low (D4) 28 3-11 Undervoltage 30
- 3-12 Underfrequency 31 3-13 Containment Pressure - High 1, High 2 and High 3 32
". 3-14 Pressurizer Pressure - Low, Safety injection 33 3-15 Sterniline Pressure - Low 34 3-16 Negative Steamline Pressure Rate - High 35 3-17 Steam Generator Water Level - High-High (D4) 36 3-18 Tavg - Low, Low-Low N-16 37 3-19 RWST Level - Low-Low 39 3-20 Reactor Protection System / Engineered Safety Features 40 Actuation System Channel Error Allowances Notes to Table 3-20 41 iii
.'- LIST OF TABLES CONTINUED
.T.at!lt ' Tit 1e EA22 3-21 Overtemperature N-16 Gain Calculations 42 3-22 Overpower N-16 Gain Calculations 44.
3-23 Steam Generator Level Density Variations 46 3-24 AP Measurements Expressed in Flow Units 47 3-25 Tavg - Low, Low-Low N 16 Gain Calculations 49 3-26 Precision HCS Flow Measurement 51 4-1 Examples of Current STS Setpoints Philosophy 60 4-2 Exa.mples of Westinghouse STS Rack Allowance 60 4-3 Westinghouse Protection System STS Setpoint Inputs 63 Notes to Table 4-3 64 e
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LIST OF ILLUSTRATIONS l
Fiaure Title Paae 4-1 NUREG-0452 Rev. 4 Setpoint Error 61 Breakdown 4-2 Westinghouse STS Setpoint Error 62 Breakdown e
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1.0 INTRODUCTION
In March of 1977, the NRC requested several utilities with Westinghouse Nuclear Steam Supply Systems to reply to a series of questions concerning the methodology for determining instrument setpoints. A revised methodology was developed in response to those questions with a correspo.. jing defense of the technique used in determining the overall allowance for each setpoint.
The basic underlying assumption used is that several of the error components and their parameter assumptions act independently, e.g.,
rack versus sensors and pressure / temperature assumptions. This allows the use of a statistical summation of the various breakdown components instead of a strictly arithmetic summation. A direct benefit of the use of this technique is increased margin in the total
, allowance. For those parameter assumptions known to be interactive, the technique uses the standard, conservative approach, arithmetic summation, to form independent quantities, e.g., drift and calibration error. An explanation of the overall approach is provided in Section 2.0.
Section 3.0 provides a description, or definition, of each of the various components in the setpoint parameter breakdown, to allow a clear understanding of the breakdown. Also provided is a detailed example of each setpoint margin calculation demonstrating the technique and noting how each parameter value is derived. In all cases, margin exists between the summation and the total allowance.
Section 4.0 notes what the current Standard Technical Specifications use for setpoints and an explanation of the impact of the Westinghouse approach on them. Detailed examples of how to determine the Technical Specification setpoint values are also provided. An Appendix is provided noting a recommended set of Technical Specifications using the plant specific data in the Westinghouse approach.
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? 2.0 COMBINATION OF ERROR COMPONENTS
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2.1 METHODOLOGY The methodology used to combine the error components for a channel is an appropriate combination cf those groups which are statistically independent, i.e., not interactive. Those errors which are not independent are placed arithmetically into groups that are and can then be systematically combined.
The methodology used is the " square root of the z. of the squares" which has been utilized in other Westinghouse repor. This technique, or others of a similar nature, have been used in WCAP-103950) and WCAP-8567(2) . WCAP-8567 is approved by the NRC noting acceptability of statistical techniques for the application requested. Also, various ANSI, American Nuclear Society, and Instrument Society of America standards approve the use of probabilistic and statistical techniques in determining
". safety-related setpoints(3)(4) The methodology used in this report is essentially the same as that used for V. C. Summer in August, 1982; approved in NUREG 0717, Supplement No. 4(5),
(1) Grigsby, J. M., Spier, E. M., Tuley, C. R., " Statistical Evaluation of LOCA Heat Source Uncertainty", WCAP-10395 (Pr'oprietary), WCAP-10396 (Non-Proprietary), November, 1983.
(2) Chelemer, H., Boman, L. H., and Sharp, D. R., " Improved Thermal Design Procedure", WCAP-8567 (Proprietary), WCAP-8568 (Non-Proprietary), July,1975.
(3) ANSI /ANS Standard 58.4-1979, " Criteria for Technical Specifications for Nuclear Power Stations".
(4) ISA Standard 567.04, 1987, "Setpoints for Nuclear Safety-Related Instrumentation Used in Nuclear Power Plants".
, (5) NUREG-0717, Supplement No. 4, " Safety Evaluation Report related to the Operation of Virgil C. Summer Nuclear Station, Unit No.
1", Docket No. 50-395, August, 1982.
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.' The relationship.between tLe error components and the total error for ,
a channel is noted in Eq. 2.1, CSA - ((PMA)2 + (PEA)2 + (SCA+SMTE+SD)2 + (SPE)2 + (STE)2 +
(RCA+RMTE+RCSA+RD)2 +(RTE)2)l/2 + EA (Eq. 2.1) where: l CSA = Channel Statistical Allowance l PMA - Process Measurement Accuracy PEA = Primary Element Accuracy SCA = Sensor Calibration Accuracy SMTE - Sensor Measurement and Test Equipment Accuracy SD - Sensor Drift SPE - Sensor Pressure Effects STE - Sensor Temperature Effects
- RCA - Rack Calibration Accuracy RMTE - Rack Measurement and Test Equipment Accuracy
- RCSA = Rack Comparator Setting Accuracy RD = Rack Drift RTE = Rack Temperature Effects EA = Environmental Allowance As can be seen in the equation, drift and calibration accuracy allowances are interactive and thus not independent. The environmental allowance is not necessarily considered interactive with all other parameters, but as an additional degree of conservatism is added to the statistical sum. It should be noted that for this document, it is assumed that the accuracy effect on a channel due to cable degradation in an accident environment is less than 0.1 % of span. Less than this magnitude of uncertainty is .
," considered negligible and is not factored into the calculations. An error due to this cause, found in excess of 0.1 % of span is arithmetically summed as an environmental (EA) error.
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- The Westinghouse setpoint methodology results in a value with a 95 % I probability with a high confidence level. With the exception of Process Measurement Accuracy, Rack Drift, and Sensor Drift, all uncertainties assumed are the extremes of the ranges of the various parameters, i.e., are better than two o values. Rack Drift and Sensor Drift are assumed, based on a survey of reported plant LERs, and with Process Measurement Accuracy, are considered conservative values.
2.2 SENSOR ALLOWANCES Five parameters are considered to be sensor allowances, SCA, SMTE, SD, SPE, and STE (see Table 3-20). Of these parameters, two are considered to be statistically independent, SPE and STE, and three are considered interactive, SCA, SMTE and SD. SPE and STE are considered to be independent due to the manner in which the
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instruments +. ion is checked, i.e., the instrumentation is calibrated and drift determined under conditions in which pressure and
, temperature are assumed constant. An example of this would be as follows; assume a sensor is placed in some position in the containment during a refueling outage. After placement, an instrument technician calibrates the sensor. This calibration is performed at ambient pressure and temperature conditions. Some time later with the plant shutdown, an instrument technician checks for sensor ririft. Using the same technique as for calibrating the sensor, the technician determines if the sensor has drifted. The conditions under which this determination is made are again at ambient pressure and temperature. Thus the temperature and pressure have no impact on the drift determination and are, therefore, independent of the drift allowance.
SCA, SMTE and SD are considered to be interactive for the same reason that SPE and STE are considered independent, i.e., due to the manner in which the instrumentation is checked. Instrumentation calibration techniques use the same process as determining instrument drift, that 4
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l is, the end result of the two is the same. When calibrating a
' .1 sensor, the _ sensor output is checked to determine if it is representing accurately the input. The same is performed for a determination of the sensor drift. Thus unless "as left/as found" data is recorded and used, it is impossible to detemir.a the differences between calibration errors and drift when a sensor is checked the second or any subsequent time. Based on this reasoning, SCA, SMTE and SD have been added,to form an independent group which is then factored into Equation 2.1. An example of the impact of this treatment for a level transmitter is (sensor parameters only):
-+a,c SCA -
SMTE -
SPE -
STE -
SD -
. extracting the sensor portion of Equation 2.1 results in;
((SCA + SMTE + SD)2 + (SPE)2 + (STE)2)l/2
[ ]+a,c - 2.12 %
Assuming no interactive effects for any of the parameters results in the following: .
((SCA)2 + (SMTE)2 + (50)2 + (SPE)2 + (STE)2)l/2 (Eq. 2.2)
[ I]+a,c - 1.41 % '
Thus it can be seen that the approach represented by Equation 2.1, which accounts for interactive parameters, results in a more conservative summation of the allowances.
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- 2.3 RACK ALLOWANCES I Five parameters, as noted by Table 3-20, are considered to be rack allowances, RCA, RMTE, RCSA, RTE, and RD. Four of these parameters are considered to be interactive (for much the same reason outlined for sensors in 2.2), RCA, RMTE, RCSA, and RD. When calibrating or determining drift in the racks for a specific channel, the processes' are performed at essentially constant temperature, i.e., ambient temperature. Because of this, the RTE parameter is considered to be independent of any factors for calibration or drift. However, the same cannot be said for the other rack parameters. As noted in 2.2, when calibrating or determining drift for a channel, the same end result is desired, that is, at what point does the bistable change state. After initial calibration, without recording and using "as left/as found" data, it is not possible to distinguish the difference between a calibration error, rack drift or a comparator setting
- error. Based on this logic, these factors have been added to form an independent group. This group is then factored into Equation 2.1.
', The impact of this approach (formation of an independent group based ofs interactive components) is significant. For a level transmitter channel, using the same approach outlined in Equations 2.1 and 2.2 results in the following: {
+a,c RCA - {
RMTE =
RCSA -
3 RTE -
RD -
extracting the rack portion of Equation 2.1 results in;
((RCA + RMTE + RCSA + RD)2 + (RTE)2)l/2
[ ]+a,c = 1.94 %
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? Assuming no interactive effects for any of the parameters yields the following less conservative results; l l
((RCA)2 + (RMTE)2 + (RCSA)2 + (RD)2 + (RTE)2)l/2 (Eq. 2.3) l
[. ]+a,c - 1.26 %
Thus, the impact of the use of Equation 2.1 is even greater in the area of rack effects than for the sensor. Therefore, accounting for interactive effects in the treatment of these allowances insures a conservative result.
2.4 PROCESS All0WANCES Finally, the PMA and PEA parameters are considered to be independent of both sensor and rack parameters. PMA provides allowances for the
', non-instrument related effects, e.g., neutron flux, calorimetric power error assumptions, fluid density changes, and temperature
', stratification assumptions. PMA may consist of more than one independent error allowance. PEA accounts for errors due to metering devices, such as elbows and venturis. Thus, these parameters have been factored into Equation 2.1 as independent quantities.
2.5 MEASUREMENT AND TEST E0VIPMENT ACCURACY l
l Westinghouse has been informed by Comanche Peak that some of the l equipment used for calibration and analog channel operational testing (ACOT) of the transmitters and racks does not meet SAMA standard PMC 20.1-1973(I) with regards to test equipment accuracy of 10 % or l less of the calibration accuracy (referenced in 3.2.6.a and 3.2.7.a.
l (1) Scientific Apparatus Manufacturers Association, Standard PMC 20.1-1973, " Process Measurement and Control Terminology".
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ofthis' report).. This requires'the inclusion of the accuracy of this equipment in the basic equations 2.1 and 3.1. ; Based on information provided by the plant, these additional uncertainties are included in the calculations (as noted on the tables included in this report)
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with some impact on the final results. On Table 3-20, the values of SMTE and RMTE are identified explicitly.
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f 3.0 PROTECTION SYSTEM SETPOINT METHODOLOGY J 3.1 MARGIN CALCULATION As noted in Section Two. Westinghouse utilizes the square root of the sum of the squares for summation of the various components of the channel breakdown. This approach is valid where no dependency is present. An arithmetic summation is required where an interaction between two parameters exists. The equation used to determine the margin, and thus the acceptability of the parameter values used, is:
Margin = TA - ((PMA)2 + (PEA)2 + (SCA+SMTE+SD)2 + (SPE)2 ,
(STE)2 + (RCA+RM1E+RCSA+RD)2 + (RTE)2)l/2 - EA (Eq. 3.1) where:
TA = Total Allowance (Safety Analysis Limit - Nominal Trip Setpoint),and all other parameters are as defined for Equation 2.1.
Using Equation 2.1, Equation 3.1 may be simplified to:
Margin - TA - CSA (Eq. 3.2)
Tables 3-1 through 3-19 provide individual channel breakdown and CSA calculations for all protection functions utilizing 7300 process rack equipment. Table 3-20 provides s summary of the previous 19 tables and includes Safety Analysis and Technical Specification values, Total A11owan:e and Margin.
3.2 DEFINITIONS FOR PROTECTION SYSTEM SETPOINT TOLERANCES To insure a clear understanding of the channel breakdown used in this report, the following definitions are noted:
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l- 1. Trio Accuracy
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The tolerance band containing the highest expected value of the difference between (a) the desired trip point value of a process variable and (b), the actual value at which a comparator trips (and thus actuates some desired result). This is the tolerance band, in %
of span, within which the complete channel must perform its intended trip function. It includes comparator setting accuracy, channel accuracy (including the sensor) for each input, and environmental effects on the rack mounted electronics. It comprises all instrumentation errors; however, it does not include Process Measurement Accuracy.
- 2. Process Measurement Accuracy Includes plant variable measurement errors up to but not including
$ the sensor. Examples are the effect of fluid stratification on
, temperature measurements and the effect of changing fluid density on level measurements.
- 3. Actuation Accuracy Synonymous with trip accuracy, but used where the word " trip" does not apply.
- 4. Indication Accuracy The tolerance band containing tne highest expected v61ue of the difference between (a) the value of a process variable read on an indicator or recorder and (b) the actual value of that process
.. variable. An indication must fall within this tolerance band. It includes channel accuracy, accuracy of readout devices, and rack environmental effects, but not process measurement accuracy such as fluid stratification. It also assumes a controlled environment for the readout device.
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- 5. Channel Accuracy
,- The accuracy of an analog channel which includes the accuracy of the primary element and/or transmitter and modules in the chain where calibration of modules intermediate in a chain is allowed to compansate for errors in other modules of the chain. Rack environmental effects are not included here to avoid duplication due !
' to dual' inputs, however, normal environmental ef fects on field mounted hardware is included.
- 6. Sensor Allowable Deviation The accuracy that can be expected in the field. It includes drift, temperature effects, field calibration and for the case of Ap '
transmitters, an allowance for the effect of static pressure variations.
The tolerances are as follows:
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- a. Reference (calibration) accuracy - [ ]+a,c unless other data indicates ebre inaccuracy. This accuracy is the SAMA reference accuracy as defined in SAMA standard PMC 20.1-1973(l).
- b. Measurement and Test Equipment accuracy - usually included as an integral part of (a), Reference (calibration) accuracy, when less than 10 % of the value of (a). .For equipment (DVM, pressure gauge, etc.) used to calibrate the sensor with larger uncertainty values, a specific allowance is made.
(1) Scientific Apparatus Manufacturers Association, Standard PMC 20.1-1973, " Process Measurement and Control Terminology".
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. c. Temperature effect - [ )+a,c based on a nominal temperature coefficient of [ 1+a,c/100 Of and a I maximum assumed change of 50 O f from a reference 0
temperature, of 70 F.
- d. Pressure effect - usually calibrated out because pressure is constant. If not constant, a nominal [ )+a,c is used. Present data indicates a static pressure effect of approximately [ ]+a,c/1000 psi.
- e. Drift - change in input-output relationship over a period of time at reference conditions (e.g., constant temperature -
[ )+a,c ofspan).
- 7. Rack Allowable Deviation
, The tolerances are as follows:
'. a. Rack Calibration Accuracy The accuracy that can be expected during a calibration at reference conditions. This accuracy is the SAMA reference accuracy as defined in SAMA standard PMC 20.1-1973(l).
This includes all modules in a rack and is a total of
[ )+a,c of span, assuming the chain of modules is I tuned to this accuracy. For simple loops where a power supply (not used as a converter) is the only rack module, this accuracy may be ignored. All rack modules individually must have a reference accuracy within [ J+a,c, (1) Scientific Apparatus Manufacturers Association, Standard PMC 20.1-1973, " Process Measurement and Control Terminology".
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.' b. Measurement and Test Equipment Accuracy i Is usually included as an integral part of (a), Reference (calibration) accuracy, when less than 10 % of the value of (a). For equipment (DVM, current source, voltage source, etc.) used to calibrate the racks with larger uncertainty i values, a specific allowance is made.
- c. Rack Environmental Effects Includes effects of temperature, humidity, voltage and frequency changes, of which temperature is the most significant. An accuracy of [ ]+a,c, is used which ,
considers a nominal ambient temperature of 70 0F with extremes to 40 Of and 120 0 F for short periods of time.
- d. Rack Drift
', Instrument channel drift - change in input-output relationship over a period of time at reference conditions (e.g., constant temper ature) - i 1.0 % of span.
- e. Rac Comparator Setting Accuracy Assum ug an exact electronic input, (note that the " channel accuract" takes care of deviations from this ideal), the tolerance on the precision with which a comparator trip value can ta set, within such practical constraints as time and effort e>3 ended in making the setting.
The tolerances assmed for Comanche Peak are as follows:
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." (a) Fixed setpoint with a single input - [ ]+a,c span. This assumes that comparator nonlinearities are compensated by the setpoint.
(b) Dual input - an additional [. ]+a,c span must be added for comparator nonlinearities between two inputs.
Total accuracy is [ ]+a,c span.
Note: The following four definitions are currently used in the Standardized Technical Specifications (STS).
- 8. Nominal Safety System Settina The desired setpoint for the variable. Initial calibration and subsequent recalibrations should be made at the nominal safety system setting (" Trip Setpoint" in STS).
- 9. Limitino Safety System Settina A setting chosen to prevent exceeding a Safety Analysis Limit
(' Allowable Values" in STS). Violation of this setting may be an STS violation.
- 10. Allowance for Instrument Channel Drift ,
The difference between (8) and (9) taken in the conservative direction.
- 11. Safety Analysis limit
, The setpoint value assumed in safety analyses.
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. 12. Total Allowable Setooint Deviation
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Maximum setpoint deviation from a nominal value due to instrument (hardware) effects.
3.3 METHODOLOGY CONCLUSION The Westinghouse setpoint methodology results in a value with a 95 %
probability with a high confidence level. With the exception of Process Measurement Accuracy, Rack Drift and Sensor Drift, all uncertainties assumed are the extremes of the ranges of the various parameters, i.e., are larger than two o values. Rack Drift and Sensor Drift are assumed, based on a survey of reported plant LERs, and with Process Measurement Accuracy are considered as conservative values.
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TABLE 3-1 POWER RANGE, NEUTRON FLUX - HIGH AND LOW SETPOINTS lJ; Parameter Allowance
- Process Measurement Accuracy
+a,c -
-+a,c Primary Element Accuracy Sensor Calibration
[ ]+a,c Sensor Pressure Effects Sen or Temperature Effects Sensor Drift
[ 3+a,c Environmental Allowance Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy Comparator One input Rack Temperature Effects Rack Drift
- In % span (120 % Rated Thermal Power)
Channel Statistical Allowance -
+a,c m
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l TABLE 3-2 (Continued) l POWER RANGE, NEUTRON FLUX - HIGH POSITIVE RATE AND HIGH NEGATIVE RATE Channel Statistical Allowance -
+a,c 4
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I L TABLE 3-2 POWER RANGE, NEUTRON FLUX - HIGH POSITIVE RATE AND HIGH NEGATIVE RATE l Parameter Allowance
- Process Measurement Accuracy l
+a,c -
-+a,c Primary Element Accuracy Sensor Calibration '
+a,c Sensor Pressure Effects Sensor Temperature Effects '
-+a,c Sensor Drift
+a,c 4
Environmental Allowance .
Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy Comparator One input [ ]+a,c Rack Temperature Effects Rack Drift
.- In % span (120 % Rated Thermal Power) o .
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i TABLE 3-3 i
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- INTERME'DIATE RANGE, NEUTRON FLUX
, - Parameter ellowance*
Process Measurement Accuracy
+a,c
+a,C
' Primary Element Accuracy Sensor Calibration
[. )+a,c Sensor Pressure Effects Sensor Temperature Effects
[ J+a,c Sensor Drift
[ )+a,c Environmental Allowance
, Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy Comparator One input Rack Temperature Effects Rack Drift 5 % RTP
- In % span (conservatively assumed to be 120 % Rated Thermal Power)
Channel Statistical Allowance -
+a,c i l
mm> sammm i
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TABLE 3-4 L- SOURCE RANGE, NEUTRON FLUX-
- _ Parameter Allowance
- Process Measurement Accuracy
+a,c
-+a,c Primary Element Accuracy Sensor Calibration .
[ j i'a , c
,, Sensor Pressure Effects' Sensor. Temperature Effects
.)+a,c Sensor Drift
[ 3+a,c
. Environmental Allowance
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. ~ Rack Calibration Rack Accuracy
. Measurement & Test Equipment Accuracy Comparator One input Rack Temperature Effects-RackDrif)'
3 x 10 cps
- In % span (1 x 106 cps)
Channel Statistical Allowance -
+a,c O
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. TABLE 3-5
.. OVERTEMPERATURE N-16
, Paraneter Allowance
- Process Measurement Accuracy
+a,c .-
Aq -
i_ _
Primary Element Accuracy Sensor Calibration '
16 N
+'
RTD -
Pressure - -
i- _ _
Measurement & Test Equipment Accuracy Pressure - [- ]+a,c Sensor Pressure Effects
. Sensor Temperature Effects 16 N
+'
Pressure -
Sensor Drift
+'
16N -
RTD -
Pressure -
Environmental Allowance Rack Calibration 16N -
Tc ~
Tc -
Pressure -
Aq -
e 21 I. . . . . .. . . . . . . . . . .
......._...--------------..-----i. -- .- -
TABLE 3-5 (Continued)
Parameter Allowance
- l Measurement & Test Equipment Accuracy
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+a,C ~
+a,C T -
c lT c '
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Pressure -
Aq -
Rack' Accuracy 16 N Total 16 N -
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Tc ~
Pressure -
Aq -
Rack Comparator Setting Accuracy Two inputs Rack Temperature Effects
. p . ]+a,c Rack Drift 16g l
Setpoint reference signal i
- In % span (pressure - 800 psi, Tc - 120 0 F, 16N - 150 % RTP, Aq - 60 % Aq)
- See Table 3-21 for gain and conversion calculations Channe3 Statistical Allowance -
+a,c e*
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TABLE 3-6 c
OVERPOWER N-16 Parameter Allowance *
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Process MeasurementiAccuracy
.+a,C -
Primary Element Accuracy Sensor Calibration 16 N -
RTD -
Sensor Pressure Effects i Sensor. Temperature Effects 16 N -
+'
Sensor Drift
+a,c
- 16 N .
RTD -
Environmental Allowance RTD -[ ]+a,c Rack, Calibration 16 N -
T -
Setpoint - I Measurement & Test Equipment Accuracy 16 N -
T ~
c _ _
Rack Accuracy
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16 N 23 1
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o TABLE 3-6 Continued
+a,c Total E
16N T
Setpoint Rack Comparator Setting Accuracy Two inputs Rack Temperature Effects ,
[ ;J+a,c Rack Drift-16 N Setpoint
- In % span (Tc - 120 0,F 16 N - 150 % RTP)
. ** See Table 3-22 for gain and conversion calculation Channel Statistical Allowance =
+a,c 4
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I TABLE 3-7
. t PRESSURIZER PRESSURE - LOW AND HIGH, REACTOR TRIPS Parameter Allowance
- Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Measurement.& Test Equipment Accuracy Sensor Pressure Effects i Sensor Temperature Effects Sensor Drift Low High [ ]+a,c Environmental Allowance 4 Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy Comparator One input Rack Temperature Effects-1 Rack Drift In % span (800 psi)
Channel Statistical Allowance -
+a,c
{
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l TABLE 3-8 lI' PRESSURIZER WATER LEVEL - HIGH
.- Parameter Allowance
- Process Measurement Accuracy
+a C
[ ]+a,c ,
Primary Element Accuracy Sensor Calibration
~"'"
Measurement & Test Equipment Accuracy 1
Sensor Pressure Effects i
Sensor Temperature Effects Sensor Drift Environmental Allowance Rack Calibration Rack Accuracy '
. Measurement & Test Equipment Accuracy 4
Comparator One input Rack Temperature Effects Rack Drift
_ mm
- In % span (100 % span)
Channel Statistical Allowance =
+a,c m em e
k 26
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4: TABLE 3-9 'l LOSS OF FLOW
. Parameter Allowance
- Process Measurement Accuracy r- -
+a,c - -
+a,c Primary Element Accuracy
[ J+a,c Sensor Calibration
[- )+a,c Sensor Pressure Effects
[ 3+a,c Sensor Temperature Effects j+a,c
[
- Sensor Drift ~
l
[ ]+a,c
$ Environmental Allowance .
Rack Calibration Rack Accuracy [ ]+a,c Measurement & Test Equipment Accuracy [ ]+a,c Comparator One input [ )+a,c Rack Temperature Effects
[ )+a,c Rack Drift 1.0 % AP span In % flow span (120 % Thermal Design Flow) % AP span converted to flow span via Equation 3-24.8, with Fmax = 120 % and FN = 100 %
,. Channel Statistical Allowance =
+a,c a
1 27
TABLE 3-10 i..
-STEAM GENERATOR WATER LEVEL - LOW-LOW (D4)'
f Parameter Allowance
- Process Measurement Accuracy -- --
+a,c Density variations with load **
Primary Element Accuracy Sensor Calibration Accuracy Measurement & Test Equipment Accuracy Sensor Pressure Effects.
Sensor Temperature Effects Sensor Drift Environmental Allowance (For Feedbreak)
Transmitter Reference leg heatup Cable IR Bias Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy Rack Comparator Setting Accuracy One input
- Rack Temperature Effects Rack Drift L_ __
- In % span (100 % span)
- See Table 3-23.
4 O
28
TABLE 3-10 (Continued)
S STEAM GENERATOR WATER LEVEL - LOW-LOW (04)
. Channel Statistical Allowance =
Loss of Normal Feeaw.':-
+a,c 1
Feedbreak
-+a,c e
S G
e
)
O 29
TABLE 3-11 UNDERVOLTAGE
~
. - EArameter Allowance *
+a,c Process Measurement Accuracy
]
Primary Element Accuracy Sensor Calibration Sensor Pressure Effects Sensor Temperature Effects-Sensor Drift Environmental Allowance Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy
- Comparator Rack Temperature Effects Rack Drift I
- In % span (1800 VAC)
Channel Statistical Allowance -
+a,c M
W Y
30
a .
TABLE 3-12 UNDERFREQUENCY Parameter Allowance *
+a.c Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift i Environmental Allowance Rack Calibration Rack Accuracy -
Measurement & Test Equipment Accuracy
~
Comparator
. Rack Temperature Effects Rack Drift In % span (4.5 Hz)
Channel Statistical Allowance =
-+a,c 31 l f
TABLE 3-13.
CONTAINMENT PRESSURE - HIGH 1, HIGH 2, AND HIGH 3 Parameter Allowance
- 4 8, C Process. Measurement Accuracy Primary Element Accuracy Sensor Calibration
. Measurement & Test Equipment Accuracy Sensor Pressure Effects sensor Temperature Effects Sensor Drift-Environmental Allowance Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy ,
". Comparator One input-
'. Rack Temperature Effects Rack Drift (0.65 psig) -
- In % spcn (65 psig)
Channel Statistical Allowance =
+a,c
/
e 32 L
L
1 TABLE 3-14 l.' PRESSURIZER PRESSURE - LOW, SAFETY INJECTION
. Parameter Allowance *
+a,c Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects .
Sensor Drift l Environmental Allowance Transmitter Cable IR
^
Rack Calibration
~
Rack Accuracy
, Measurement & Test Equipment Accuracy Comparator
. One input Rack Temperature Effects Rack Drift
- In % span (800 psi)
Channel Statistical Allowance -
l- -+a,c W
h 33
, c
-> TABLE 3-15 STEAMLINE PRESSURE - LOW
- Parameter ' Allowance *
+a,C .
Process Measurement Accuracy I Primary Element Accuracy
-i Sensor Calibration Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift +
Environmental Allowance Transmitter Cable IR Rack Calibration
". Rack Accuracy Measurement & Test Equipment Accuracy
. Comparator -
One input Rack Temperature Effects l
Rack Drift
- In % span (1300 psig)
Channel Statistical Allowance -
+a,c O
O 34 l
l
- _ _ ___-_-_ U
T 4'
n TABLE-3-16 NEGATIVE STEAMLINE PRESSURE RATE I - HIGH l- Parameter Allowance *
-+B,C Process Measurement Accuracy Primary Element Accuracy Sensor Calibration
+a,c Sensor Pressure Effects Sensor Temperature Effects
-+a,C Sensor Drift
-+a,c I
Environmental Allowance Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy Comparator One input Rack Temperature Effects Rack Drift
- In percent span (1300 psig)
Channel Statistical Allownace - -
+a,c I 1.
35
. . . ..i. . . _ _ _ - - . . . . - - - - - - - - - - - - - - - - - - - - - - -
l TABLE 3-17 l
STEAM GENERATOR WATER LEVEL - HIGH-HIGH (D4)
'l Parameter Allowance
- Process Measurement Accuracy - --
+a,c Density variations with load **
Primary Element Accuracy Sensor Calibration Accuracy Measurement & Test Equipment Accuracy Sensot Pressura Effects Sensor Temperature Effects Sensor Drift .
Environmental Allowance Bias
[- )+a,c
~- Rack Calibration Rack Accuracy Measurement & Test Equipment Accuracy Rack Comparator Setting Accuracy One input Rack Temperature Effects Rack Drift
- In % span (100 % span)
- See Table 3-23.
Channel Statistical Allowance -
-+a,c nous Em 36
l TABLE 3-18 L .* TAVG LOW, LOW-LOW N-16
, Parameter. Allowance
- Process Measurement Accuracy
+a,c -
-+a,c 16 N-16y.
16 N-Primhry Element Accuracy Sensor Calibration 16 N
+'
'etTO -
Sensor Pressure Effects Sensor Temperature Effects
+a,c 16 N -
, Sensor Drift 16 N
+'
RTD -
Environmental Allowance Rack Calibration
+'
16N -
Tc -
T -
c .
Measurement & Test Equipment Accuracy
+a,c 16 g .
Tc -
Tc -
Rack Accuracy 16 N ]+a,c
-[
37
i L.
, . < TABLE 3-18 (Continued) .
Y l.
l* -: -+a,c Total l .* . 16 N IC
- Rack Comparator Setting Accuracy
- One input Rack Temperature Effects
[ )+a,c l
Rack Drift 16N T c-L _
- In % span (T c
- 120'0F, 16 N - 150 % RTP, Tavg - 100 0F ).
. ** See Table 25 for conversion calculations.
Channel Statistical Allowance'-
+a,c num emm
'^ 45 d
38 a.
p l.
l l TABLE 3-19 l **
RWST LEVEL - LOW-LOW r -
Parameter Allowance *
+a,c Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects .
Sensor Drift (9 month calibration interval)
Environmental Allowance i Rack Calibration Rack-Accuracy.
Measurement & Test Equipment Accuracy
~
Comparator One input 4 .
Rack Temperature Effects Rack Drift In % span (513.0 inches of water column)
Channel Statistical Allowance =
+a,c
-- _J ,
l 1
6 ,'
39 i
a I
o-TASLE' IU ELE
. ' COMANCHE P p........................ .. ..... SENSOR ******************
. 1 2 3 4' _5 6 7 PROCESS PRIMARY MEASUREMENT PROTECil0N CHANNEL MEASUREMENT ELEMENT CAllGRAfl0N & TEST EQUIP PRESSURE TEMPERATURE l ACCURACT ACCURACY ACCURACT ACCURACT EFFECTS effec 15 DRIFT (1) (1) (1) (1) (1) (1) (1) 1 POWER RANGE, NEUTRON F'kA NIGH SEiP0lNT 2 POW 1 RANCE, NEUTRON FLUX - LOW SETPolNT 3 POW R RANGE, NEUTRON ILUX
- NIGN POSlflVE RATE l 4 power RANCE, NEUTRON FLUX a MIGN NECAtlVE RATE 5 lNTERMEDIAlt RANCE, NEUTRON FLUX 6 SOURCE RANGE, NEUTRON FLUK .-
T OVERTEMPERATURE N*16
- N*16 CHANNEL 8 f gCHANNEL 9
10 ]
g PaESSUN12ER PRES $URE CHANNEL 11 f F(CELIA q) CHANNEL j
, 12 OVERPOWER N 16
- N*16 CHANNEL 13 SETPOINT 14 f CNANNEL 15 PRESSUR12ER PRESSURE
- LOW, REACTOR TRIP 16 PRES $URIZER PRESSURE
- HIGN 17 PRESSURIZER UATER LEVEL
- NIGH s 18 LOSS OF FLOW 19 SIEAM GENERATOR WATER LEVEL
- LOW-LOW 20 UNDERVOLTAGE = RCP
. 21 LNDERFREQUENCY
- RCP l
, 22 CONTAINMENT PRESSURE
- HIGH 1 23 PRES $URIZER PRES $URE LOW, Si 24 STEAMLINE PRESSURE
- LOW l I
25 STEAMLINE PRESSURE NEGAflVE' RATE = NIGH 26 CONTAINNEN! PRESSURE
- MIGH+2 21 CONTAINMENT PRESSURE
- NGH+3 28 STEAM GENERATOR WAFER (EVEL
- HIGH+HlGH 29 RWSi LEVEL
- LOW LOW 30 favg
- LOW LQJ f, CHANNEL 31 32 N 16 CHANNEL
_ l k.
^
2_
J 20 alt 4 UNii 1
...... .. ..,j,.. .............. ....INSTRt# TENT RACK------- - --- - -- *l 8 9 10 11 12 13 14 15 16 17 to ?*_
MEASUREMENT CO9PARATOR SAFElf $15 515 CHANNEL hlRCMMCNTAL Call 0RAll0N & TEsf EQUIP StillNG TEMPERATURE AAALYSis ALLOWA8tE TRiv TOTAL SIAllsflCAL ALLOWANCE ACCURACY ACCURACY ACCURACY EffECis ORiff L1Mll VALUE StiP0lNI ALLOWANCE ALLOWANCE MARGlu (1) (1) (1) (1) ( R .,,, (1) (2) (3) (3) (O (1) (1) ,,,,
1.0 118 % RTP 111.7 % STP 109 % RTP 1 j 1.0 35 % RIP 27.7 % RTP 25 % RTP 2 ;
O.5 6.T % RTP 6.3 % RIP 5.0 X RIP 4 4.2 (5) 31.5 % RTP 25 % RTP 5 3.0 ?5) 1.4E*5 CPS 1.0E+5 CPS 6 1.0 7 1.0 8 -
FUhtfl0N (6) FUNCil0N (?) TUNCil0N (7) 9
+1.8 % SPAN 10 11 1.0 12 0.5 116 % RTP 115.1 % RTP 112 % RTP 13 14 1.0 1845 PSIG 1863.6 PSIG 1830 PSIG 15 1.0 2445 PStG 2400.8 PSIC 2385 PSIC 16 1.0 (5) 93.9 % SPAN 92 % SPAN 17 0.6 87 % FLOW 88.6 % FLOW 90 % FLOW 18 1.0 0 % SPAN 26.4 1 SPAN 28.0 % SPAN 19 1.4 4692 VAC (10) 4752.6 VAC 4830 VAC 20 0.7 57.0 Hz (10) 57.1 Hz 57.2 Ha 2) 1.0 5.0 PSIG (10) 3.8 PSIG 3.2 PSIG 22 1.0 1700 PSIG (10) 1803.6 PSIG 1820 PSIG 23 1.0 380 PSIC (10) 593.5 PSIG 605 PSIG 24 5.0 (5) 178.7 PSIG 100 PSIG 25 1.0 8.0 PSIC (10) 6.8 PSIG 6.2 PSIC 26 1.0 20.0 Psic (10) 18.8 PSIG 18.2 PSIG 27 1.0 90 % SPAN 84.3 % SPAN 82.4 % SPAN 28 1.0 (5) 38.4 % SPAN 39.6 1 SPAN 29 1.0 30 (5) 546.6 *F 550.0 *F 31 1.0 32 L -
APERTUF C AP.D Also Available On Apwf ure Card 990F050 a -ol .
w
f: NOTES FOR TABLE 3-20
~
- 1. All values in % span.
- 2. As noted in Table 15.0-4 of FSAR.
- 3. As noted in Tables 2.2-1 and 3.3-4 of Plant' Technical Specifications.
- 4. Included in [ ]+a,c
- 5. 'Not used in the Safety Ana',ysis.
- 6. As noted in Figure 15.1-1 of FSAR.
- 7. As noted in Table 2.2-1 Note 1 of Plant Technical Specifications.
- 8. [- ]+a,c
- 9. Included in [' ]+a,c
- 10. Not noted in Table 15.0-4 of FSAR but used in Safety Analysis.
4 n
/
i A
41
TABLE 3-21 OVERTEMPERATURE N-16 CALCULATIONS
, The equation for Overtemperature N-16 is:
OT16NsK 1 - {K2 [((I + 7 15)/(I + 7 S))T 2 e -T c 3 + K 3 (P - P') - f (Aq)) 1 where:
OT 16, . <(3 73 5)/(1 + 725))qi q3 - K8(16N )(1-K7 [l/(1 + 73 S))[l/(1 + 74 5)]II/(1 + 75 3)3){II + ES (Tc-Tc ]/[1 + K6 (I ' 4 13) 16N 16N PWR g- K N) -K 10N2 N,N2 i = outputs of the top two sections of the excore detectors.
K nom -
1.078TechnicalSpecifgagionvalue Kf((max)inal) =
=
.[
0.00948 3
K2 K3
- 0.000494 vessel AT = 618.8 - 559.6 - 59.2'F Aq gain = 1.40 % RTP/% Aq Calculations converted to 16N span (150 % RTP)
' -+a,c
, PMA -
1 PMA2
=
PMS3 PMA 4 =
PMA5 w
O 42
l l
TABLE 3-21 Continued j
., Gain calculations:
,. Temperature - (100 % RTP)(K 2 ) = 0.948 1/*F .l Pressure - (100 % RTP)(K3_) = 0.049 1/ psi Temperature calculations:
+a,c SCA =
3 SD i -
- e RCA3 RCA g =
RMTE3 RMTE2 Pressure calculations.
+a,c SCA 7 -
SMTE2
' STE2
- SD2
=
RCAg
, RMTt4 _ _
Other calculations:
+a,c RCA3 RMTE 3 =
RCAg -
RMTES _ _
- +a,c TA -
- e-
-+a,c P
43 i
l TABLE 3-22
~'
+ OVERPOWER N-16 CALCULATIONS
' The equation for Overpower AT is:
OP16N5K4 - f 2(aq) where:
OP163 , ((j # y 3)f() + 7 g))q q} = K8 (16N )(1 -
K7 [l/(1 + 73 5)][l/(I ~+ 74 5)][1/(1 + 57 5)l}{Il + K5 (T c -Tc 3/II + K6 (I ~ Al l) 16N 16N PWR - KgN) - K 10Np N,N2 3 = outputs of the top two sections of the excore detectors.
K4 (nominal) - 1.03 Technical Specification value K4 (max) -
[ ]+a,c K5
= 0.0006 vessel AT = 618.8 - 559.6 - 59.2'F
. f 2(Aq) gain = 0.0
^
Calculations converted to '16N span (150 % RTP)
. 1.0 % RTP = 0.6*F
-+a,C PMA -
3 PMAp PMS3
- m-k g es 44
, i:
.'h! =
1.
0(
1 .I','
L WESTINGHOUSE PROPRIETARY CLASS 2-1 TABLE 3-22 Continued
.f,
- ;.< Temperature calculations:
+a,c SCA -
3" SD =
.m. RCA =
e 3 RMTEi--
EA =
a i"
Other calculations:
-+a,c RCA2 B'
RMTE2 RCA3 _ _
5 - -
+a,C TA =
+8,C i
4 45
1 TABLE 3-23
. STEAM GENERATOR LEVEL DENSITY VARIATIONS 8ecause of density. variations with load, it is impossible without some l
form of compensation to have the same accuracy under all load conditions.
The recommended calibration point is at 70 % power conditions.
~
Approximate errors at 0 % and 100 % water level readings and also for nominal trip points'of 26 % and 82 % level are listed below for a 70 % i power condition calibration. This is a specific calculation for Comanche Peak Unit 1 only. These errors are only from density changes and do not reflect channel accuracies, trip accuracies or indicated accuracies which !
have been defined as AP measurements only.
INDICATED LEVEL (70 % Power Calibration)
$ 0% 26 % 82 % 100 %
Actual Level - -
+a,c 0 % Power Actual Level ,
100 % Power
_ ]
0 46
TABLE 3-24 AP MEASUREMENTS EXPRESSED IN FLOW UNITS The AP accuracy expressed as % of span of the transmitter applies throughout the measured span, i.e., i 1.5 % of 100 inches AP =
1.5 inches anywhere in the span. Because F2 = f(AP) the same cannot be said for flow accuracies. When it is more convenient to express the accuracy of a transmitter in flow terms, the following method is used:
(FN ) = AP N where N = nominal flow 2FN8FN = SAPN thus SFN = (JAPg)/2? N Eq. 3-24.1 Error at a point (not in %) is:
BFN /IN = (SAPg )/2(FN)2 = (SAPN )/2(APN ) Eq. 3-24.2 and (APN )/(APmax) * (fN ) /(Imax) Eq. 3-24.3 where max = maximum flow i
and the transmitter AP error is:
(SAPN /APmax)(100) = % error in Full Scale AP (% FS AP) Eq. 3-24.4 i
47
_ _ _ _ __- _ _ _ _ __ _ _ _ _ _ _ m
therefore:
. OfN/FN
= (APmax)((% FS AP)/100)/2(AP,,y)(FN/Imax)
= ((% FS AP)/(2)(100))(Fmax/F N )2 Eq. 3-24.5
- Error in flow units is:
BF N = FN ((% FS AP)/(2)(100(Feax/IN ) Eq. 3-24.6 Error in % nominal flow is: (BFN/IN)(100) = ((% FS AP)/2)(Fmax/FN ) Eq. 3-24.7-Error in % full span is: (BFN /Imax)D00)
'. - {(F )(% N FS AP)/(Fmax)(2)(100))(Fmax/IN )
,, = ((% FS AP)/2)(Fmax/IN ) Eq. 3-24.8 Equation 3-24.8 is used to express errors in % full spaa in this document. l i 48 >
i TABLE 3-25 TAVG - LOW, LOW-LOW N-16 GAIN CALCULATIONS The equation for Tavg is: , 6 Tavg - Tc+ N3 where: 16 N3 = ((1)/(1 + 7 3S))q3 qi = K8(16N )(1-K7 [l/(1 + 73 5)3II/(I + 74 5)3II/(I + 75S)33(Il + K5 (Te-Tc 3/II + K6 (I - 41 }} 16N = 16N PWR - Kg N 3 - K10N2 N,N2 3 = outputs of the top two sections of:the excore detectors. Vessel AT = 618.8 - 559.2*F = 59.2*F Tavg span - 100*F 1 % RTP = 0.6*F => 1.0*F = 1.7 % RTP
+a,c PMA 3 -
PMA p = PMS3 Temperature calculations:
+a,c SCA =
SD =
=
RCA) RCA = RMTky - RMTE2 -- __ . 9
+a ,C e
49
1 s q TABLE 3-25 Continued 16ti calculations:
-+a,c RCA3 RMTE 3 -
W RTE = < 4 O e S
+
50
_ ,!.'I l - TABLE 3-26 PRECISION RCS FLOW MEASUREMENT Parameter Allowance
- Pressurizer pressure uncertainty - Cold Leg Specific - --
+a,c t
Volume [ ]+a,c Pressurizer pressure uncertainty - Hot Leg Specific , Volume [ ]+a,c i TC uncertei.;y - Cold Leg Specific Volume [ ]+a,c TC uncertainty - Hot Leg Specific Volume [ ]+a,c Hot Leg Volumetric Flow uncertainty Hot Leg Volumetric Flow uncertainty - Hot Leg Specific Volume - randon
- systematic Precision Calorimetric Loop Power uncertainty - Hot Leg Specific Volume Procedure Convergence Error on loop Power - Hot-Leg Specific Volume [ ]+a,c
- In % Flow Total Error =
+a,c E
h 51 ;
4.0 TECHNICAL SPECIFICATION USAGE 4.1 CURRENT USE 1: The Standard Technical Specifications (STS) as used for Westinghouse type plant designs (see NUREG-0452, Revision 4) utilizes a two column , format for the RPS and ESF system. This format recognizes that the l setpoint channel breakdown, as presented in Figure 4-1, allows for a certain amount of rack drift. The original intent was to reduce the number of reporting events in the area of instrumentation setpoint drift. It appears that this goal was achieved. However, it does not recognize how setpoint calibrations and verifications are performed in the plant. In fact, this two column approach forces the plant to take a double penalty in the area of calibration error. As noted in Figure 4-1, the plant must allow for calibration error below the STS Trip Setpoint, in addition to the allowance assumed in the various accident analyses, if full utilization of the rack drift is wanted. This is due, as noted in 2.2', to the fact that calibration error cannot be distinguished from rack drift after an initial calibration. Thus, the
, plant is left with two choices; 1) to assume a rack drift value less than that allowed for in the analyses (actual RD - assumed RD - RCA) or, 2) penalize the operatien of the plant (and increasing the ,
possibility of a spurious trip) by lowering the nominal trip setpoint ; into the operating margin. The use of the summation technique described in Section ? of this report allows for a natural extension of the two column approach. This extension recognizes the calibration / verification techniques used in the plants and allows for a more flexible approach in determining deportability. Also of significant benefit to the plant is the incorporation of sensor drift parameters on an 18 month basis (or more often if necessary). 0 52 J
i 4.2 MESilNGH0VSE SETPOINT METHODOLOGY FOR STS SETPOINTS Recognizing that the plant experiences both rack and sensor drift, a
.' -different approach to Technical Specification setpoints may be used.
This revised methodology accounts for two additional factors seen in the plant during periodic surveillance,1) interactive effects for both' sensors and rack and, 2) sensor drift effects. 4.2.] RACK ALLOWANCE Interactive effects will be covered first. When an instrument technician looks for t-ack drift, more than that is seen if "as left/as found" data is not used. This interaction has been noted several times and is treated in Equations 2.1 and 3.] by the arithmetic summation of the rack effects, RD, RM&TE, RCSA, and RCA; and the sensor effects, SD, SM&TE and SCA. To provide a conservative
" trigger value", the difference between the STS trip setpoint and the STS aewable value is determined by two methods. The first is simply th< values used in the CSA calculation, T) - (RCA + RMTE + RCSA + RD) (Eq. 4.-1)
The second extracts these values from the calculations and compares the remaining values against the total allowance: 1 T2 - TA - {(A) + (5)2}I/2 - EA (Eq. 4.2) where: T2 - Rack trigger value A - (PMA)2 + (PEA)2 + (SPE)2 + (STE)2 + (RTE)2 S - (SCA + SMTE + SD) EA, TA and all other parameters are ai defined for Equation 2.1. 4 53
l
.. . I The smaller of the trigger values should be used for comparison with the "as measured" (RCA + RMTE + RCSA + RD) value. As long as the "as measured" value is smaller, the channel is within the accuracy l allowance. If the "as measured" value exceeds the " trigger value",
the actual number should be used in the calculation described in Section 4.2.3. This means that all the instrument technician has to I do during the periodic surveillance is determine the value of the bistable trip setpoint, verify that it is less than the STS Allowable Value, and does not have to account for any additional effects. The same approach is used for the sensor, i.e., the "as measured" value is used when required. Tables 4-1 and 4-2 show the current STS i setpoint philosophy (NUREG-0452, Revision 4) and the Westinghouse rack allowance for Virgil C. Summer (31 day surveillance only), values larger than those noted in Table 3-20 will be justified by Comanche Peak. A comparison of the differences between the Safety Analysis Limits and Allowable Values will show the relative gain of the Westinghouse version. 4.2.2 INCLUSION OF "AS MEASURED" SENSOR ALLOWANCE If the approach used was a straight arithmetic sum, sensor allowances for drift would also be straight. forward, i.e., a three column setpoint methodology. However, the use of the Westinghouse ; methodology requires a somewhat more complicated approach. The methodology is based on the use of Equation 4.3, and demonstrated in l Section 4.2.3, Implementation. TA 2 (A)l/2 + R + S + EA (Eq. 4.3) where: R = the "as measured rack value" (RCA + RMTE + RCSA - xD) S = the "as measured sensor value" (SCA + SMTE + SD) ;
# all other param'eters are as defined in Equation 4.2.
1 54 I
Equation 4.3 can be reduced further, for use in the STS to:
' TA 2 Z + R + S (Eq. 4.4) where:
2 - (A)l/2 + EA Equation 4.3 would be used in two instances, 1) when the "as measured" rack setpoint value exceeds the rack " trigger value" as defined by the STS Allowable Value, and, 2) when determining that the "as measured" sensor value is within acceptable values as utilized in the various Safety Analyses and verified every 18 months. 4.2.3 IMPLEMENTATION OF THE WESTINGHOUSE SETPOINT METHODOLOGY Implementation of this methodology is reasonably straight forward. Appendix A provides a text and tarles for use at Virgil C. Summer. An example of how the specification would be used for the Pressurizer Pressure - Low reactor trip is as follows. d
~
For the periodic surveillance, as required by Table 4.3-1 of NUREG-0452, Revision 4, a functional test would be performed on the channels of this trip function. During this test the bistable trip ! setpoint woulo De determined for each channel. If the "as measured" bistable trip setpoint error was found to be less than or equal to i that required by the Allowable Value, no action would be necessary by the plant staff. The Allowable Value is determined by Equation 4.2 as follows: T2 TA - ((A) + (S)2)l/2 - EA t 55
I p
.l l where: -
[, TA - 4.5 % (an assumed value for this example)
- -+a,c
. A -
- S -
EA - T2
- l However, since only T3-{ J+a,c is assumed for T in the various analyses, that value will be used as the ." trigger value".
The lowest of two values is used for the " trigger value'; either the value for T asse:ned in the analyses or the value calculated by Equation 4.2. Now assume that one bistable has " drifted" more than that allowed by the STS for periodic surveillance. According to ACTION statement
. b.1, the plant staff must verify that Equation 2.2-1 is met. Going 1 to Table 2.2-1, the following values are noted: Z - 0.71-and the assumed Total Allowance is (TA) - 4.5. Assume that the "as~ measured" rack setpoint value is 2.75 % low and the "zt reasured" sensor value !
I is 1.5 %. Equation 2.2-1 looks like. 3
)
) TA 2 Z + R + S 0.71 + 2.75 + 1.5 s 4.5 5.0 > 4.5 As can be seen, 5.0 % is not less than 4.5 % thus, the plant staff must follow ACTION statement b.2 (declare channel inoperable and place in the " tripped" condition). It should be noted that if the j plant staff had not measured the sensor drift, but instead used the I value of S in Table 2.2-1 then the sum of Z + R + S would also be
.- greater than 4.5 %. In fact, anytime the "as measured" value for o .
I 1 1 56 l r
rack drift is ' greater than T (the " trigger value") and there is less r ,' than 1.0 % margin, use of S in Table 2.2-1 will result in the sua of Z + R + S being greater than TA and require the reporting of the case- .' to the NRC. If the sum of R + S was about 0.5 % less, e.g , R = 2.25 L S - 1.5 % . thus, R + 5 = 3.75 %, then the sum of 2 + R ihould be less, than 4.5 %. Under this condition, the plant staff weufd recalibrates the instrumentation, as good engineering practice suggests, b: t the incident is not reportable, even though the " trigger value' is exceeded, because Equation 2.2-1 was satisfied. In the determination of T for a function with multiple channel inputs there is a sligr,t disagreement between Westinghouse proposed methodology sr' NRC approveo methodology. Westinghouse believes toat T si,ould 8 / either: Ty - (RCA3 RMTE3 + RCSA; + RD3 ) +
~
( T '. Ap + RMTE2 + RCSA2 + RD2 ) (Eq. 4.5) or T2 - TA - (A + (S3 )2 + (S2 )2))/ - EA (Eq. 4.6) w'iere the subscript 1 and 2 denote r.hannels 1 and 2, and the value of
! used is whichever is smaller.
The NRC in turn has approved a method of determining T for a multiple channel input function as follows, either: 4 T3 - ((RCA3 +RMTE) + RCSA)3 + RD )2 (RCA2 + RMTE 2 + RCSA2 2 + RD ) ) / (Eq. 4.7) ; or Equation 4.6 at described above. 1 f l f -
i f l. Again the value of T used is whichever is smaller. This method is
.'~ described in'NUREG-0717 Supplement 4, dated August 1982. !
." The complete set of calculations follows for Overpower 16 N to demonstrate this aspect (values noted are from Table 3-6). ,
+a,c TA -
A - S3, -7 52 T 2 = TA - (A + (SI )2 + (S2 ) }
+a,c T2 "I 3 T3 - ((RCATc + RMTETc) + (RCASTPT + RCSASTPT +RDSTPT +
(RCA16N + RMTE16N + Accuracy + RCSA16N + RD16g )2)l/2
~
+a,c T3*
The value of T used is based on Equation 4.6 (T2 ). In this document Equations 4.6 and 4.7, whichever results in the smaller ' value, is used for multiple channel input functions to remain consistent with current NRC approved methodologies. Table 4-3 notes the values of TA, A, S, T, and Z for all protection functions and is utilized in the determination of the Allowable Values noted in Appendix A. l l l 7@le 4.3-1 also requires that a calibration be performed every refueling (approximately 18 months). To satisfy this requirement, the plant staff would determine the bistable trip setpoint (thus, determining the "as measured" rack value at that time) and the sensor "as measured" value. Taking these two "as measured" values and using 58
j l-L I- Equation 2.2-1 again the plant staff can determine that the tested
. channel is.in fact within the Safety Analysis allowance.
1-
4.3 CONCLUSION
Using the above methodology, the plant gains added operational flexibility and yet remains within the allowances cccounted for in the various accident analyses. In addition, the methodology allows for a sensor drift factor and an increased rack drift factor. These two gains should significantly reduce the problems associated with channel drift and thus, decrease the number of reportable events while allowing plant operation in a safe manner. W e e e 59
l TABLE 4-1 EXAMPLES OF CURRENT STS SETPOINT PHILOSOPHY . Power Range Pressurizer Neutron Flux - Hiah Pressure - Low Safety Analysis Limit 118 % RTP 1845 psig STS Allowable Value 110 % RTP 1870 psig STS Trip Setpoint 109 % RTP 1880 psig
\
TABLE 4-2 EXAMPLES OF WESTINGHOUSE STS RACK ALLOWANCE I Power Range Pressurizer Neutron Flux - Hiah Pressure - Low Safety Analysis Limit 118 % RTP 1845 psig STS Allowable Value 111.7 % RTP 1864.8 psig k (Trigger Value) STS Trip Setpoint 109 % RTP 1880 psig
=
60
1 J '." Safety Analysis Limit l i l.......... Process Measurement Accuracy ( j.......... i ( Primary Element Accuracy l.......... { Sensor Calibration Accuracy j.......... ( Sensor Measurement & Test Equipment j.......... ( Sensor Pressure Effects l.......... ( Sensor Temperature Effects j.......... ( Sensor Drift /< j.......... ( ( Environmental Allowance
.' j..........
( Rack Temperature Effects l.......... ( Rack Comparator Setting Accuracy j.......... ( Rack Calibration Accuracy l.......... ( Rack Measurement & Test Equipment STS Allowable Value l--------- ( Rack Drift STS Trip Setpoint Actual Calibration Setpoint Figure 4-1 NUREG-0452 Rev. 4 Setpoint Error Breakdown 61
c, . 1 i
. Safety Analysis Limit l..........
L ,' ' 4- , { Process Measurement /Ac. curacy l.......... ( Primary Element Accuracy J l- {.......... ; { Senser Calibration Accuracy l.......... ( Sensor Measmement & Test Equipment l.......... ( Sensor Pressure Effects j.......... ( -Sensor Temperature Effects l.......... ( Sensor Drift j.......... ( Environmental Allowance-t j........... { Rack Temperature Effects
~
STS Allowable Value l.......... (. Rack Comparator Setting Accuracy l........... ( Rack Calibration Accuracy j.......... { Rack Measurement & Test Equipment { Rack Drift - STS Trip Setpoint Figure 4 2 Westinghouse STS Setpoint Error Breakdown 62
l
~ ~ c:
WESilNGHOUSE PR0!ECII COMA
- l TOTAL !
ALLOWANCE (7) (7) (7) ; PROTECTION CHANNEL (TA) (71 (A) (1) (S) (Zj (T) (3) R2j l _ ._ + 0, C j 1 POWER RANGE, NEUIRON FLUX - HICH SEIP0lNT 7. 5 0.0 2.3 2 POWER RANCE, NEUIRON FLUX - LOW SETPOINT 8.3 0.0 2.3 3 POWER RANGE, NEUTRON FLUX - HIGH POSITIVE RATE 1.6 0.0 1.1 4 P0uEk RANCE, NEUlkON FLUX - HICH NECATIVE RATE 1.6 0.0 1.1 ! 5 INTERMEDI ATE RANGE, NEUTRON FLUX 17.0 0.0 5.5 7 SOURCE RANCE, NEUIRON FLUX 17.0 0.0 4.3 8 OVERTEMPERATURE N-16 5.8 1.2 + 0.8 1.8 9 OVERPOWER N-16 4.0 0.0 2.1 10 PRESSURIZER PRESSURE - LOW, REACIOR TRIP 4.4 2.0 2.1 11 PRESSURIZER PRESSURE - HIGH 7.5 1.0 2.0 13 PRESSURIZER WATER LEVEL HICH 8.0 2.0 1.9 14 LOSS OF FLOW 2.5 0.6 1.1 15 STEAM CENERATOR WATER LEVEL - LOW LOW 28.0 2.0 l' .6 l 16 UNDERVOLTACE - RCP 7. 7 0.0 4.3 17 UNDERFREQUENCY RCP 4.4 0.0 2.0 19 CONTAINMENT PRESSURE - HIGH 1 2.7 1.7 0.9 20 PRESSURIZER PRESSURE - LOW, S.I. 15.0 2.0 2.1 i k 21 STEAMLINE PRES $0WE - LOW 17.3 2.0 0.9 j 22 STEAMLINE PRESSURE NECAilVE RATE - HIGH 8.0 0.0 6.1 23 CONTAINMENT PRESSURE - HIGH 2 2.7 1.7 0.9 25 CONTAINMENT PRESSURE - HlCH 3 2.7 1.7 0.9 26 STEAM CENERATOR VATER LEVEL - HIGH HICH 7.6 2.0 1.9 27 RWST LEVEL - LOW LOW 2.6 1.3 1.2 28 f avg LOW LOW 5.6 1.2 3.4 63 )
~
M NM
g.-. ADLE 4 3
'SYSitM 515 SETPolNT JNPUIS tE PEAK LMIT 1 (7) INSTRUMENT STS TI:!P STS ALLOWAGli MAX IMl#4 SPAN SETPOiNF VALUE VALUE (9) l l4.56 120 % RTP 109 % RTP 111.7 % RIP 112.5 % RIP 1 4.56 120 % RIP 25 % RTP 27.7 % RTP 29.5 % RIP 2 l0.5 120 % RIP 5.0 % RTP 6.3 % RTP 6.3 % RTP 3
'0. 5 120 % RIP 5.0 % RTP 6.3 % RTP 6.3 % RTP 4 8.41 120 % RIP 25 % RTP 31.5 % RTP 35.3 % RTP 5 0.01 1E+06 CPS 1E+05 CPS 1.4E+05 CPS 1.7E+05 CPS 7 3.65 (5) FUNCil0N (8) TUNCil0N (8)+1.8 % SPAN FUNCTION (8)*0.7 % SPAN 8 1.93 (6) 112 % RTP 115.1 % RTP 115.1 % RIP 9 D.7) 800 PSI 1880 PSIG 1863.6 PSIG 1866.7 PSIG 10 5.01 800 PSI 2385 PSIC 2400.8 PSIG 2396.9 PSIG 11 2.18 100 % SPAN 92 % SPAN 93.9 % SPAN 95.8 % SPAN 13 1.18 120 % DESIGN FLOW 90 % ft0W 88.6 % FLOW 89.1 % FLOW 14 5.58 100 % SPAN 28 % SPAN 26.4 % SPAN 27.6 % SPAN 15 ).O 1000 VAC 4830 VAC 4752 VAC 4692 VAC 16 ).O 4.5 H 57.2 Hz 57.1 Hz 57.0 Hz 17 ).71 65 PSI 3.2 Psic 3.8 PSIG 3.5 PSIG ' 'e ).91 800 PSI 1820 PSIG 1803.6 PSIC 1803.3 PSIC 20 i.01 1300 PSI 605 PSIG 593.5 PSIG 601.1 PSIG 21 l.50 1300 PSI 100 PSIC 178.7 PSIC 197.5 PSic 22 v . 71 65 PSI 6.2 P$1G 6.8 PSIC 6.5 PSIC 23 ' 74
. 65 PSI 18.2 PSIG 18.0 PSIG 18.5 PSIG 25
.28 100 % SPAN 82.4 % SPAN 84.3 % SPAN 83.7 % SPAN 26
.71 513 IN H 0 39.6 % SPAN 38.4 % SPAN 7 39.0 % SPAN 27
.75 100 f 550 F 546.6 f 547.4 f 28 S1 Al'ERTURL CARIf Also Availal)lc On Apertitre Card N090s O ^ 29 0F
~
l
- 1. s NOTES FOR TABLE 4-3 (1) A - (PMA)2 + (PEA)2 + (SPE)2 + (STE)2 + (RTE)2 (2) S - SCA + SD (3) T3 - RCA + RMTE + RCSA + RD T2 - TA - (A + (53)2 4 (52 ) ) / - EA T3 - ((RCA) + RMTE3 + RCSA3 1+ RD )2 +
(RCA2 + RMTE2 + RCSA2 + RD2 )2)l/2 T = minimum of Tj, T2 or T3
~
(4) Z - (A)l/2 + EA (5) Parameter Soan 16 N 150 % RTP Pressure 800 PSIG T c 120*F I Aq 120 % Aq o (6) Parameter Enn 16 N 150 % RTP T c 120*F q (7) All values in % Span (8) As noted in Notes 1 and 2 of Table 2.2-1 of Technical Specifications N 4 r k 64
NOTES FOR TABLE 4-3 (Continued) e b (9) This column provides the maximum value for a bistable assuming that the transmitter is not evaluated and the values for S, 2 and TA from this table are used in the following equation: R - TA'- Z - S. This implys that the transmitter is assumed to be at it's maximum allowed calibration and drift deviation in the non-conservative direction. With a bistable's Trip Setpoint found in excess of the value noted in this column, it is possible (but not known absolutely) that a channel would be considered inoperable. This must be tempered by the transmitter assumption noted above, i.e., the transmitter is assumed to be at it's worst acceptable condition. a b e f n A 65
9 3 APPENDIX A SAMPLE COMANCHE PEAK UNIT I SETPOINT TECHNICAL SPECIFICATIONS O i 66
I 1 i SAFETY LIMITS AND LIMITING SAFETY SYSTEM SETTINGS r-j
, 2.2 LIMITING SAFETY SYSTEM SETTINGS l .
REACTOR TRIP SYSTEM INSTRUMENTATION SETPOINTS 2.2.1 The Reactor Trip System Instrumentation and Interlock Setpoints sf c11 be set consistent with the Trip Setpoint values shown in Table 2.2-1. APPLICABILITY: As shown for each channel in Table 3.3-1. ACTION:
- a. With a Reactor Trip System Instrumentation or Interlock Setpoint less conservative than the value shown in the Trip Setpoint columh but more conservative than the value shown in the Allowable Value Column of Table 2.2-1, adjust the Setpoint consistent with the Trip Setpoint value.
- b. With the Reactor Trip System Instrumentation or Interlock Setpoint less conservative than the value shown in the Allowable Values column of Table 2.2-1, either:
- 1. Adjust the Setpoint consistent with the Trip Setpoint value of Table 2.2-1 and determine within 12 hours that Equation 2.2-1 was satisfied for the affected channel, or
- 2. Declare the channel inoperable and apply the applicable ACTION statement requirement of Specification 3.3-1 until >
the channel is restored to OPERABLE status with its setpoint adjusted consistant with the Trip Setpoint value. s
. TA 2 Z + R + S (Equation 2.2-1) 67_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
where:
,'. Z - The value from Column Z of Table 2.2-1 for the affected channel, R - Tne "as measured" value ("as found" - nominal in %
span) of rack error for.the affected channel, S - Either the "as measured" value ("as found" - nominal in
% span) of the sensor error, or the value from Column S (Sensor Drift) of Table 2.2-1.for the affected channel, and TA - The value from Column TA (Total Allowance) of Table 2.2-1 for the affected channel.
s a 68
2.2 LIMITING SAFETY SYSTEM SETTINGS BASES s 2.2.1 REACTOR TRIP SY5 TEM INSTRUMENTATION SETPOINTS The Reactor Trip Setpoint Limits specified in Table 2.2-1 are the nominal values at which the Reactor Trips are set for each functional unit. The Trip Setpoints have been selected Lo ensure that the reactor core and reactor coolant system are prevented from exceeding their safety limits during normal operation and design basis anticipated operational occurrences and to assist the Engineered Safety Features Actuation System in mitigating the consequences of accidents. The setpoint for a reactor trip system or interlock function is considered to be adjusted consistent with the nominal value when the "as measured" ("as left") setpoint is within the band allowed for calibration accuracy. I To accommodate the instrument drift assumed to occur between
~
operational tests and the accuracy to which setpoints can be measured and calibrated, Allowable Values for the reactor trip setpoints have been specified in Table 2.2-1. Operation with setpoints less conservative than the Trip Setpoint but within the Allowable Value is acceptable since an allowance has been made in the safety analysis to accommodate this error. An optional provision has been included for determining the OPERABILITY of a channel when its trip setpoint is found to exceed the Allowable Value. The methodology of this option utilizes the "as measured" ("as found") deviation from the specified calibration point for rack and sensor components, in conjunction with j a statistical combination of the other uncertainties of the instrumentation to measure the process variable, and the uncertainties in calibrating the instrumentation. In Equation 2.2-1, TA 1 Z + R + S, the interactive effects of the errors in the rack and { the sensor, and the "as measured" ("as found" - nominal) values of the errors are considered. Z, as specified in Table 2.2-1, in I 69 L__----_________ ______ __--- -- - - - - - -
% span,.is the statistical summation of errors assumed in the J. analysis excluding those associated with the sensor and rack drift
, and the accuracy of their measurement. TA or Total Allowance is the difference, in % span, between the trip setpoint and the value used in'the analysis for reactor trip. R or Rack Error is the "as measured" deviation ("as found" - nominal), in % span, for the !
affected channel from the specified trip setpoint. S or Sensor Drift l is either the "as measured" deviation ("as found" - nominal) of the sensor from its calibration point or the value specified in Table 2.2-1, in % span, from the analysis assumptions. Use of Equation 2.2-1 allows. for a sensor drift factor, an increased rack drift l factor, and provides a threshold value for determining deportability. The methodology to derive the trip setpoints is based upon combining-all of the uncertainties in the channels. Inherent to the determination of the trip setpoints are the magnitudes of these channel uncertainties. Sensors and other instrumentation utilized in k these channels are expected to be capable of operating within the
, allowances of these uncertainty magnitudes. Rack drift in excess of . the Allowable Value exhibits the behavior that the rack has not met its allowance. Being that there is a small statistical chance that this will happen, an infrequent e.xcessive drift is expected. Rack or sensor drift, in excess of the allowance that is more than occasional, may be indicative of more serious problems and should warrant further investigation.
70
3/4.3.2 ENGINEERE'D SAFETY FEATURE ACTUATION SYSTEM INSTRUMENTATION e,
.. LIMITING CONDITION FOR OPERATION 3.3.2 The Engineered Safety Feature Actuation System (ESFAS) instrumentation channels and interlocks shown in Table 3.3-3 shall be OPERABLE with their Trip Setpcints set consistent with the values shown in the Trip Setpoint column of Table 3.3-4 and with RESPONSE TIMES as shown in Table 3.3-5.
APPLICABILITY: As shown in Table 3.3-3. ACTION:
- a. With an ESFAS Instrumentation or Interlock Setpoint less conservative than the value shown in the Trip Setpoint column but more conservative than the value shown in the Allowable Value
<[ column of Table 3.3-4 adjust the Setpoint consistent with the Trip Setpoint value.
- b. With an ESFAS Instrumentation or Interlock Setpoint less conservative than the value shown in the Allowable Value column of Table 3.3-4, either:
- 1. Adjust the Setpoin; consistent with the Trip Setpoint value of Table 3.3-4 anc determine within 12 hours that Equation 2.2-1 was satisfied for the affected channel, or * ,
l 2. Declare the channel inoperable and apply the applicable l ACTION statement requirements of Table 3.3-3 until the channel is restored to OPERABLE status with its Setpoint adjusted consistent with the Trip Setpoint value.
.. TA 2 Z + R + S (Equation 2.2-1) 71
,a where: ' l' Z - The value for Column Z of Table 3.3-4 for the affected channel, a
R - The "as measured" value ("as found" - nominal in % span) of rack error for the affected channel, S - Either the "as measured" value ("as found" - nominal in
% span) of the sensor error, or the value from Column S (Senser Drift) of Table 3.3-4 for the aff ected channel, ar,d TA - The value from Columa TA (Total Allowance) of Table 3.3-4 for the affected channel.
l 9 t
'W 4*
8 72
1 J 3/4.3 INSTRUMENTATION I
. BASES 3/4.3.1 and 3/4.3.2 REACTOR TRIP AND ENGINEERED SAFETY FEATURE (
ACTUATION SYSTEM INSTRUMENTATION l 1 The OPERABILITY of the Reactor Protection System and Engineered Safety Feature Actuation System Instrumentation and interlocks ensure that-1) the associated action and/or reactor trip will be initiated when the parameter monitored by each channel or combination thereof reaches its setpoint, 2) the specified coincidence logic is maintained, 3) sufficient redundancy is maintained to permit a channel to be out of service for testing or maintenance, and 4) sufficient system functional capability is available from diverse parameters. I; The OPERABILITY of these systems is required to provide the overall ., reliability, redundancy, and diversity assumed available in the facility design for the protection and mitigation of accident and transient conditions. The integrated operation of each of these systems is consistent with the assumptions used in the accident Jialyses. The surveillance requirements specified for these systems
<isuro that the overall system functional capability is maintained 3mparable to the original design standards. The periodic surveillance tests performed at the minimum frequencies are sufficient to demonstrate this capability.
The Engineered Safety Feature Actuation System Instrumentation Trip Setpoints specified in Table 3.3-4 are the nominal values at which the bistables are set for each functional unit. A setpoint is considered to be adjusted consistent with the nominal value when the.
"as measured" setpoint ("as left") is within the band allowed for
, calibration accuracy.
I3
.(
To accommodate the instrument drift assumed to occur between-
.- operational tests and the accuracy to which setpoints can be measured and calibrated, Allowable Values fo- the setpoints have been
** specified in Table 3.3-4. Operation with setpoints less conservative than the Trip Setpoint but within the Allowable' Value is acceptable since an allowance has been made in the safety analysis to accomodate this error. An optional provision has been included for determining the OPERABILITY of a channel when its trip setpoint is found to exceed the Allowable Value. The methodology of this option utilizes the'"as measured" ("as found") deviation from the specified calibration point for rack and sensor components, in conjunction with a statistical combination of the other uncertainties of the instrumentation to measure the process variable, and the uncertainties in calibrating the instrumentation. In Equation 2.2-1, TA 2 Z + R + S, the interactive effects of the errors in the rack and the sensor, and the "as measured" values of the errors are considered. 2, as specified in Table 3.3-4, in % span, is the
, statistical summation of errors assumed in the analysis excluding
( those associated with the sensor and rack drift and the accuracy of
- their measurement. TA or Total Allowance is the difference, in %
( span, between the trip setpoint and the value used in the analysis for the actuation. R or Rack Error is the "as measured" ("as found"
- nominal) deviation, in % span, for the affected channel from the specif' , trip setpoint. S or Sensor Drift is either the "as t
measured" ("as found" - nominal) deviation of the sensor from its calibration point or the value specified in Table 3.3-4, in % span, from the analysis assumptions. Use of Equation 2.2-1 allows for a sensor drift factor, an increased rack drift factor, and provides a threshold value for determining deportability. The methodology to derive the trip setpoints is based upon combining all of the uncertainties in the channels. Inherent to the 3, determination of the trip setpoints are the magnitudes of these channel uncertainties. Sensor and rack instrumentation utilized in
. these channels are expected to be capable of operating within the 74
allowances of these uncertainty magnitudes. Rack drift in excess of
. the Allowable Value exhibits the behavior that the rack has not met its allowance. Being that there is a small statistical chance that 3
this will happen, an infrequent excessive drift is expected. Rack or sensor drift, in excess of the allowance that is more than occasional, may be indicative of more serious problems and should warrant further investigation. 9 W O' s e 75
TABLE 2.2 1 l REACTOR TRIP SYSTEM INSTRL.MENTAT10N TRIP SETP01NTS
/
Jotet Functional LN t N M $$ Trio Setooint Allowable Velve
- 1. Manuel Reactor Trip kA hA NA NA NA
)
- 2. Power Range, Weutrc,n Flux, Nigh setpoint 7.5 4.56 0.0 3 109 1 RTP 1 11' '
- RTP Low Setpoint 8.3 4.56 0.0 1 25 1 RTP g 27.7 1 RTP Migh Posittw Rete 1.6 0.50 0.0 3 5 % RTP with a time 3 6.3 % RTP with a time constant 1 2 seconds constrint 1 2 seconds Nigh begative Rete 1.6 0.50 0.0 1 5 1 RTP with a time 3 6.3 % RTP with a time consterit t 2 seconds corstent 12 seconds
- 3. Intermediate Range, Woutron Flux 17.0 8.41 0.0 < 25 1 RTP < 31.5 % RTP
- 4. Source Range, heutron Flux 17.0 10.01 0.0 $ 10 CPS 1.4 x 10 CPS
- 5. Overtemperature N 16 5.8 3.65 1.2+0.8 (1) See Note 1 see Note 2
- 6. 0... power N 16 4.0 1.93 0.0 5 112 % RTP g 115.1 % RTP
- 7. Pressere Pressure Low Reactor Trip 4.4 0.71 2.0 1 1880 PSIC 1 1863.6 PstG Migh Resetor Trip 7.5 5.01 1.0 1 2385 PslG 1 2400,8 Ps!G
- 8. Pressurizer Water Level High 8.0 2.18 2.0 1 92 % span a 93.9 % Span
- 9. Loss of Flow 2.5 1.18 0.6 g 90 % Loep Flow (2) g 88.6 % Loop Flow (2)
- 10. Steen Generator Water Levet tow-Low 28.0 25.58 2.0 1 28 1 Spen 1 26.4 % span
. 11. Undervoltage RCP 7.7 0.0 0.0 6830 VAC 4753 VAC
- 12. Urderfreqsency RCP 4.4 0.0 0.0 57.2 Mz 57.1 Mz
]
- 13. Turbine Trip Low Trip System Pressure kA hA NA g 45 PS!G g 43 PSIG
^
Turbine Stop Velve Closure NA NA hA 1 1 1 Open 1 1 1 Open
- 14. Safety injection input from ESF hA NA hA NA NA
- 15. Reactor Trip system Interlocks Intermediate Range
, heutron Flux, P 6 NA hA hA N minal 1 6.0 x 10 0 ,,,, { 1.0 x 10 10 ,,,, Low Power Reactor Trips Block, P 7 P 10 input WA hA kA Nominal 10 % RTP 1 12.7 % RTP P 13 input WA NA hA Nominst 10 % Turbine 1 12.7 % Turbine ispulse Pressure lopulse Pressure eqJivalent equivalent Power Renee Neutron Flux, P8 kA NA kA Wominst 48 % RTP $ 50.7 % RTP P 10 NA NA kA mominst 10 % RTP 1 7.5 % RTP Turbine lopulse Chenber , Pressure, P 13 NA NA NA Neinst 10 % Turt>ine 512.71 Turbine I Ispulse Pressure lopulse Pressure g e @lvelent equivalent _ _
- 16. Reactor Trip Breakers kA NA NA NA NA q 17. Automatic Actuation Logic NA NA hA WA NA (1) 1.2 % Span for Dette T (RfDs) and 0.8 % for Pressurizer Pressure (2) Loop Flow a 95,700 spn l 76 1
\
TABLE 2.21 (Contirued) { REACTCR TRIP SYSTEM INSTRLMENTAfl0N TRIP SETPOINTS
, WOTAff0N ;
g NOTE 1: CNERTEMPERATURE N 16 NaK g Kg ((i + tau gS)/(1
- tou 233}I c
*I c 3 * "3(" ~ I ~ # (DELTA-q))
1 O Where:
) N = heestred k 16 Power by Ian deuters 3 i s Cold Leg temperature, *F T,o = 559.6 *F, Reference T, et RATED TMERML Podt K, 1. m g = 0.00548 (1
- toug D (1 + tou25) e The function generated by the lead leg controller for T, Wic cmm% )
taug ! tou2 = Time constants utilized in the teed leg controller for 7,, taug > 10 secs., tou2 1 3 ****' K = 0.000494 3 P a Pressurizer pressure (psig) P' > 2235 psig, seasinal RCs operating pressure S = Laplace transf orm operefor, sec*i. and f3(Dette q) is e fmetion of the indicated difference between tcp and bottom halves of detectors of the power range nucteer ton chenbers; with gains to be selected based on measured instrunent response during plant sta rt L4) tests, such that (1) for q q between 35 % and +10 %, fg (Delta q) = 0 where a *"d Ab
- b t RATED THER $L POWER in the top and bottom helves of the core respectively, and q,
- qb is the total THERMAL POWER in 1 of RATED THERMAL *M3WER.
(ii) for each 1 that the ne rfttde of et g exc -
, p set # nt shall be automatically reduced by 1.22 % of its value at RATED THERMAL POWER.
(lH) for each % that the magnitLde of q, qb exceeds +10 %, the N 16 trip setpoint shall be outcmatically reduced by 1.40 % of its value at RATED THERMAL PoutR. h NOTE 2: The channel's menintsn trip setpoint shall not exceed its corp;ted trip point by nore than 1.8 % span. o O' MW 4%ee m 77
WESTINGHOUSE PROPRIETARY CLASS 2 TABLE 3.3 4 ENGlWEERED SAFETY FEATURES ACTUATION SYSTEM INSTRI.MENTAtl0N TRIP SETPolWTS {otet 4 Functional Unit NAf A *"*$$W Trio Setacint Altoweble value
- 1. SAFETY INJECTION (ECCS, REACTOR TRIP, PMASE "A" ISOLATION, AUXILI ARY FEEDWATER MOTOR DRIVEN PLM>, TURBINE Trip, g CONTROL ROOM EMERGENCY RECIRCULATION, FEEDWATER ISOLATION, CDFONENT COOLING WATER, EMERGENCY DIESEL GENERATOR OPERATIch, CONTAINMENT OT ISCLAfl0W, ESSENTIAL VENTILAfl0N SYSTEMS, CONTAINMENT SPRAY PUMP, AND STATION SERVICE WATER.
- a. Manuel Initiation MA NA NA NA NA
- b. Automatic Actuation Logic hA NA NA NA NA
- c. Contoimmerit Pressure -
Nigh 1 2.7 0.71 1.7 3 3.2 PSIG g 3.8 PSIG
- d. Pressurizer Pressee - Low 15.0 10.91 2.0 g 1820 PSIG g 1803.6 PSIG
- e. Steam Line Pressure Low 17.3 15.01 2.0 g 605 PSIG (1) 1 593.5 PSIG (1)
- 2. CONTAINMENT SNtAY
- a. Manuet Initiation WA NA NA NA NA
- b. Autcynetic Actuation Logic NA NA NA- NA NA
- c. Containment Pressure -
High 3 2.7 0.71 1.7 3 18.2 PSIG g 18.8 PSIC
- 3. CONTAINMENT ISOLATION
- e. Phase "A" Isolation
[1] Reruel NA NA NA NA hA [2] Autcriatic Actuation Logic NA NA NA NA hA [3] Safety injection See 1. above for ett Safety injection Setpoints and Allowable values
- b. Phase "B" Isolation
[1] Manuel See item 2.s above, Phase "a" Isolation annually initiated when conteirunent Spray e is manually initiated. $ (2) Automatic Actuation Logic hA NA NA NA NA (3) Containment Pressure - Nish 3 2.7 0.71 1.7 $ 18.2 PSIG g 18.8 PSIG
^
- c. Conteirvnent Vent Isolation til Manuet See Itern 2.a and 3.e.1 above, conteirment vent Isolation is manually initiated =5en Phase "A" or Containment Spray are manually initiated.
[2] Automatic Actuation Logic NA WA NA NA NA l [3] Safety injection See 1. above for all Safety injection Setpoints and Allowable values 4 STEAM LINE ISOLATioh
- e. Manuel NA NA NA NA NA j
- b. Automatic Actuation Logic hA NA NA NA hA )
- c. Conteirvnent Pressure -
HisE 2^' --
-2r? , 0.71
.i . 7 2 6.2 PSIG g 6.8 PSIG 15.01 2.0
~
- d. Steam Line Pressure Low 17.3 1605' PSIGT17 ' g 593.5 PslG.(1)
' ' ~
- e. Ste n Line Pressure Negative Rate Nigh 8.0 0.50 0.0 5 100 PSIG $ 178.7 PSIG (1) Time constants utilized in lead leg controller ere: tou3 g 50 secs ord tau 2 5 5 secs.
- - ~ ._ d 4 78
TABLE 3.3 4 (Contiri d ) ENGlWEERLD SAFETY FEATURES ACTUAfl0N SYSTEM INSTRLNENTAfl0N TRIP SETPOINTS i' otal Fmettonat Unit {NEf M ES Trio Setootnt Attoweble Vetue s 5. TLRBINE TRIP AIC FEEDWATER ISOLATION l a. Automatic Actuation Logic NA NA NA NA- NA
- b. Steam Generator Water Levet Migh high 7.6 4.28 2.0 1 82.4 1 Span 1 84.3 % Span
- c. Safety injection See 1. above for all Saf ety injection Setpoints and Allowable Values
- 6. AUXILIARY fEEDWATER
- a. Automatic Actuation Logic NA NA kA NA NA
- b. Steam Generator Water Level Low tow 28.0 25.58 2.0 1 28 % Span 1 26.4 1 Span
- c. Safety injection Start Motor Driven Pues See 1. above for all Safety Injection Setpoints and Allowable Values
- d. Loss of Cffsite Power NA NA hA NA NA
- 7. AUTDIATIC INITI ATION OF ECCS SVITCHCP/ER TO CONT AllMENT SM
- a. Automatic Actuation Logic NA bA NA NA NA
- b. RVST Level Low Low 2.6 0.71 1.25 g 39.6 % Span 1 38.4 % Span coincident with Safety inj ec tion See 1. above for all Safety injection Setpoints and Allowable values
- 8. LOSS Of PCWER (6.9 KV SAFEGUAROS SYSTEM UNDERVOLTAGE)
- a. Preferred Offsite Source Undervoltage NA NA hA g NyS VAC 3 WyS VAC
- b. Alternate Offsite Source Undervoltage NA NA NA 3 NyS VAC g Ny$ VAC
- c. Bus Urderwltage hA NA NA >
N.VS VAC >. _ NV.S VAC 4 d. Degraded Voltage hA hA NA g NyS VAC 3 NyS VAC
, 9. CONTROL ROOM EMERGENCY RECIRCUL ATION
- s. Manual NA NA hA NA NA
- b. Automatic Actuation Logic hA NA kA NA hA
- c. Safetyinjection See 1. above for all Safety Injection Setpoints and Allowable values
- 10. ENGINEERED SAFETY FEATURE ACTUAtloh SYSTEM l *rr ocgS
- a. Pressurizer Pressure P 11 (Block) NA WA h4 N minai 1960 PSIG 1 1944.8 PSIC Not P 11 (Enable) NA hA NA N minal 1960 PSIC 1 1975.2 PSIG
- b. Reactor Trip, P 4 hA hA NA NA hA
- 11. SOL!D STATE SAFEGUARD SEQUENCER (S$$$) NA NA NA NA NA WyS e Not Westinghed e Scope 4 ,,,
e .a
'90 ea
[ 4
~ - - - -
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