ML100540144

WCAP-17044-NP, Revision 0, Westinghouse Setpoint Methodology for Protection Systems, Watts Bar Unit 2.

ML100540144
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Site:	Watts Bar
Issue date:	12/31/2009
From:	Trozzo R Westinghouse
To:	Office of Nuclear Reactor Regulation
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WCAP-17044-NP
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Westinghouse Non-Proprietary Class 3 WCAP-17044-NP Decemi ber 2009 Revision 0 Westinghouse Setpoint Methodology for Protection Systems Watts Bar Unit 2 SWestinghouse

WESTINGHOUSE NON-PROPRIETARY CLASS 3 WCAP-17044-NP REVISION 0 WESTINGHOUSE SETPOINT METHODOLOGY FOR PROTECTION SYSTEMS WATTS BAR UNIT 2 R. W. Trozzo*

Controls, Procedures & Setpoints December 2009 Reviewer: J. R.. Reagan*

Controls, Procedures & Setpoints Approved: M. B. Cerrone, Manager*

Controls, Procedures & Setpoints

• Electronicallyapproved records are authenticatedin Mhe Electronic Document Management S;stem Westinghouse Electric Company LLC P.O. Box 355 Pittsburgh, PA 15230-0355 (0 2009 Westinghouse Electric Company LLC All Rights Reserved

TABLE OF CONTENTS lIST OF TABLES ii 1.0 [NTRODUCTION 2.0 COMBINATION OF UNCERTAINTY COMPONENTS 2.1 Methodology 2 2.2 Sensor Allowances 4 2.3 Rack Allowances 5 2.4 Process Allowances 6 2.5 Measurement and Test Equipment Accuracy 7 2.6 References 7 3.0 PROTECTION SYSTEM SETPOINT METHODOLOGY 8 3.1. Margin Calculation 8 3.2 Definitions for Protection System 8 Setpoint Tolerances 3.3 Cross Reference - SAMA PMC 20.1-1973 and 17 ANSI/ilSA-S51.1-1979 3.4 References / Standards 17 3.5 Methodology Conclusion 18 4.0 APPLICATION OF THE SETPOINT METHODOLOGY 4.1 History 56 4.2 The Allowable Value 57 4.3 The Technical Specifications 61 4.4 Westinghouse Recommendations 67 WCAP- 17044-NP December 2009 Revision 0

LIST OF TABLES 3-1 Power Range, Neutron Fl ux-High and Low Setpoints .19 3-2 Power Range, Neutron Flux-High Positive Rate 20 3-3 Intermediate Range, Neutron Flux 22 3-4 Source Range, Neutron Flux 23 3-5 Overtemperature AT 24 3-6 Overpower AT 27 3-7 Pressurizer Pressure - Low and High Reactor Trip 29 3-8 Pressurizer Water Level - High 30 3-9 Reactor Coolant Flow - Low Reactor Trip 31 3-10 Steam Generator Water Level - Low-Low (Inside Containment) 33 3-10a Steam Generator Water Level - Low-Low (Outside Containment) 35 3-11 Undervoltage 37 3-12 Underfrequency 38 3-13 Containment Pressure - High, High-High 39 3-14 Pressurizer Pressure - Low, Safety Injection 40 3-15 Steamline Pressure - Low 41 3-16 Steam Generator Water Level - Hih-High 43 3-17 Negative Steamline Pressure Rate - High 44 3-18 RWST Level - Low 45 3-19 Containmnent Sump Level - tih/hiAuto Switchover 46 3-20 Vessel AT Equivalent to Power 47 3-21 Reactor Trip System/Engineered Safety Features Actuation System Channel Error Allowances 49 3-22 Overtemperature AT Calculations 50 3-23 Overpower AT Calculations 53 3-24 AP Measurements Expressed in Flow Units 54 4-1 Five Column Methodology Example 65 4-2 Reactor Trip System/Engineered Safety Features Actuation System Channel / 5 Column Methodology Results 66 WCAP-17044-NP £ December 2009 Revision 0

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 corresponding 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 components instead of a strictly arithmetic summation. A direct benefit of this technique is increased margin in the total allowance.

For those parameter assumptions known to be interactive, the techmique 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 methodology. Also provided is a detailed example of each setpoint uncertainty calculation demonstrating the methodology and noting how each parameter value is derived. In all cases, sufficient margin exists between the summation and the total allowance.

Section 4.0 references the current Watts Bar Technical Specifications 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.

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2.0 COMBINATION OF UNCERTAINTY COMPONENTS 2.1 Methodology The methodology used to combine the error components for a channel is basically the appropriate combination of those goups of components which are statistically independent, i.e., not interactive.

Those errors which are not independent are placed arithmetically into groups. The groups themselves are independent effects which can then be systematically combined.

The metlhodology used for this combination is the square root sum of the squares which has been utilized in other Westinghouse reports. This technique, or other approaches of a similar nature, has been used in WCAP-10395"' and WCAP-8567ý-1 . WCAP-8567 has been approved by the NRC staff, thus noting the acceptability of statistical techniques for the application requested. In addition, various American National Standards Institute (ANSI), American Nuclear Society, and Instrument Society of America standards approve the use of probabilistic and statistical techniques in determining safety-related setpointst34' 1. The methodology used in this report is essentially the same as that used for V. C. Summer, which was approved in NUREG-0717., Supplemrent No. 4151.

The relationship between the error components and the total error allowance for a channel is noted in Eq. 2.1.

2 2 CSA = {(PMA) + (PEA)' + (SCA + SMTE + SI) + (qP)E) + (STE)2 +

(RCA + RMTE + RCSA + RD/)2 (R TE,)/'2 + EA + BL4S Eq. 2.1 WCAP- 17044-NP 2 December 2009 Revision 0

where:

CSA = Channel Statistical Allowance PMA = Process Measurement Accuracy PEA = Primary Element Accuracy SCA - Sensor Calibration Accuracy SMTE = Sensor Measurement & Test Equipment Accuracy SD = Sensor Drift SPE Sensor Pressure Effects STE = Sensor Temperature Effects RCA = Rack Calibration Accuracy RMTE Rack Measurement & Test Equipment Accuracy RCSA = Rack Comparator Setting Accuracy RD = Rack Drift RTE = Rack Temperature Effects EA = Environmental Allowance BIAS = One directional, known magnitude allowance This equation was originally designed to address analog process racks with bistables. Digital process racks generally operate in a different manner by simulating a bistable. The protection function setpoint is a value held in memory. The digital process racks compare the function's value with the value stored in memory. A trip is initiated when the input to the calculation is compared to and corresponds to the value in memory.

Thus, with the absence of a physical bistable, the RCSA term can be redefined. Depending on the function, the RMTE term can also be redefined. The calculations for the protection ftnctions noted in this document reflect the use of either analog or digital process racks (whichever is appropriate) and the corresponding values for RCSA and RMTE as required.

As can be seen in Eq. 2.1, drift and calibration accuracy allowances are interactive and thus not independent. The EA is not necessarily considered interactive with all other parameters, but, as an additional degree of conservatism, is added to the statistical sum. Any cable insulation resistance degradation errors greater than 0. 1 % of span are treated as environmental errors and are also added to the statistical sum.

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The Westinghouse setpoint methodology results in a value with a 95 % probability with a high confidence level. Analog rack drift and sensor drift are established based on a survey of reported plant licensee event reports (LERs), vendor specifications, and Westinghouse experience. Digital rack drift is based onl system design, and Process Measurement Accuracy terms are considered to be conservative values.

2.2 Sensor Allowances Five parameters are considered to be sensor allowances: SCA, SMTE, SD, STE, and SPE (see Table 3-21). Of these parameters, two are considered to be statistically independent, STE and SPE, and three are considered interactive, SCA, SMTE and SD. STE and SPE are considered to be independent due to the manner in which the instrumentation 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 drift. Using the same technique as for calibrating the sensor, the teclmician determines if the sensor has drifted or not.

The conditions under which this determination is made are again at ambient pressure and temperature conditions. 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 STE and SPE are considered independent, i.e., due to the manner in which the instrumentation is checked. When calibrating a sensor, the sensor output is checked to determine if it is accurately representing 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 determine 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 Eq. 2.1. An example of the inpact of this treatment for a Westinghouse supplied level transmitter is (sensor parameters only):

ac SCA -

SMTE -

SPE -

STE -

SD -

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excerpting the sensor portion of Eq. 2.1 results in:

{(SCA + SMTE + SD) 2 + (SPE)2 + (STE)2} v2

- or -

[ ]' =2.1%

Assuming no interactive effects for any of the parameters results in the following:

{(SCA)2 + (SMTE) 2 + (SD) 2 + (SPE) 2 + (STE) 2}. 2 Eq. 2.2

- or -

[ C = .1.4%

Thus, it can be seen that the approach represented by Eq. 2. 1, which accounts for interactive parameters, results in a more conservative summation of the allowances.

2.3 Rack Aliowances Five parameters, as noted by Table 3-21, 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 Section 2.2), RCA, RMTE, RCSA, and RD. When calibrating or determining drift in thM 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 Section 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 Iogic, these factors have been added to form an independent group. This group is then factored into Eq.

2.1. The impact of this approach (formation of an independent group based on interactive components) is significant. For a level transmitter channel, using the same approach outlined in Eq. 2.1 and 2.2, and using analog process rack uncertainties, results in the following:

a,c RCA RMTE =

RCSA -

RTE RD =

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excerpting the rack portion of Eq. 2.1 results in:

{(RCA + RMTE + RCSA + RD)2 + (RTE)2 }"2

- or -

[.C =2.0%

Assuming no interactive effects for any of the parameters yields the following less conservative results:

{(RCA) 2 (RME)) )2 + + (RCS) 2

+ (RTE) 211/2 Eq. 2.3

- or -

I ] 'C= 1.3 %

Thus, the impact of the use of Eq. 2.1 is also significant in the area of rack effects, similar to the sensor effects previously discussed. Similar results, with different magnitudes, would be arrived at using digital process rack uncertainties. Therefore, accounting for interactive effects in the treatment of these allowances insures a conservative result.

2.4 Process Allowances 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. Recently, an improved understanding of the AP level measurement system errors has led to additional PMA error components being applied to the steam generator level channels. These error components are not always considered to be random in nature, and some tenns are treated as biases. PEA accounts for, errors due to metering devices, such as elbows and venturis. Thus, these parameters have been factored into Eq. 2.1 as independent quantities.

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2.5 Measurement and Test Equipment Accuracy Westinghouse was informed by Watts Bar that the equipment used for calibration and functional testing of the transmitters and racks did not meet SAMA standard PMC 20.1-1973 with regards to allowed exclusion 6

from the calculation' . This implies that test equipment without an accuracy of 10 % or less of the calibration accuracy is required to be included in the uncertainty calculations of Eq. 2.1 and Eq. 3.1. Based on values provided by Watts Bar personnel, these additional uncertainties were included in the calculations, as noted on the tables included in this report, with minor impact on the final results. On Table 3-21, the values for SMTE and RMTE are specifically identified.

2.6 References I. Grigsby, J. M., Spier, E. M., Tuley, C. R., "Statistical Evaluation of LOCA Heat Source Uncertainty," WCAP-10395 (Proprietary), WCAP-10396 (Non-Proprietary), November, 1983.

2. Chelemr, HI.., Bioman, 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 S67.04-1987, "Setpoints for Nuclear Safety-Related Instrumentation Used in Nuclear Power Plants."

5. NUREG-0717, Supplement No. 4, "Safety Evaluation Report Related to Operation of Virgil C. Summner Nuclear Station, Unit No. 1," Docket No. 50-395, August, 1982.

6. Scientific Apparatus Manufacturers Association, Standard PMC 20.1-1973. "Process Measurement and Control Technology."

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3.0 PROTECTION SYSTENIM SETPOINT METHOI)OLOGY 3.1, Margin Calculation As noted in Section 2.0, Westinghouse utilizes the square root of the sum of the squares for summation of the various components of the channel uncertainty. 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 is:

Margin . TA - {(PMA) + (PEA)2 + (SCA + SMTE + SD)2 + (SPE)2 +

(STE) 2 + (RCA + RMTE + RCSA + RD) 2 + (RTE)'}!' - EA - BIAS Eq. 3.1 where:

TA = Total Allowance (Safety Analysis Limit - Nominal Trip Setpoint), and all other parameters are as defined for Eq. 2. 1.

Again, please note that Eq. 3.1 is representative for a channel with analog process racks. Use of digital process racks results in modification of the RCSA term. The magnitude of the RMTE term is typically different for digital process racks when compared to typical values for analog process racks.

Tables 3-1 through 3-20 provide individual component uncertainties and CSA calculations for all protection functions utilizing appropriate values for the process rack equipment. T'able 3-21 provides a Summary of the previous 20 tables and includes Safety Analysis and Teclnical Specification values, Total Allowance and Margin.

The values in these tables are reported to one decimal place using the conventional technique of rounding down digits less than 5 and rounding up digits greater than or equal to 5. Parameters reported in the tables as "0.0" have been identified as having a value <0.04. Parameters reported as "N/A", "0", or "---" are not applicable or have no value for that channel.

3.2 Definitions for Protection System Setpoint Tolerances To ensure a clear understanding of the channel uncertainty values used in this report, the following definitions are noted:

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IMA/D Electronic circuit module that converts a continuously variable analog signal to a discrete digital signal via a prescriptive algorithm.

• Allowable Value A bistable trip setpoint (analog function) or CPU trip output (digital function) in plant Teclnical Specifications, which allows for deviation, e.g., Rack Drift, friom the Nominal Trip Setpoint (NTS). A bistable trip setpoint found non-conservative with respect to the Allowable Value (AV) requires some action for restoration by plant operating personnel.

• As Found The condition a transmitter, process rack module or process instrument loop is found in after a period of operation. Typically this condition is better than the allowance for drift (see Rack Drift and Sensor Drift),

e.g., after a period of operation, a transmitter was found to deviate friom the ideal condition by (- 0.5) %

span. This would be the "as found" condition.

M As Left The condition a transmitter, process rack module or process instrument loop is left in after calibration or bistable trip setpoint verification. This condition is better than the calibration accuracy for that piece of equipment, e.g., the permitted calibration accuracy for a transmitter may be +/- 0.5 % span; after calibration, the worst measured deviation from the ideal condition is + 0.1 % span. In this instance, if the calibration was stopped at this point, and no additional efforts were made to decrease the deviation, the "as left" error would be + 0.1 % span.

M Bias A one-directional uncertainty for a sensor, transmitter, or process parameter with a known magnitude. The instrumentation indicates higher than the actual parameter for a (+) bias, and indicates lower than the actual parameter for a (-) bias. If a sign is not identified, the bias can result in either a high or low indication.

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MChannel The sensing and process equipment, i.e.., transmitter to bistable (analog function) or transmitter to CPU trip output (digital function), for one input to the voting logic of a protection function. Westinghouse designs protection functions with voting logic made up of multiple channels, e.g. 2/3 Steam Generator Level -

Low-Low channels must have bistables in the tripped condition for a Reactor Trip to be initiated.

MChannel Statistical Allowance (CSA)

The combination of the various channel uncertainties via SRSS. It includes both instrument (sensor and process rack) uncertainties and non-instrument related effects (PMA). This parameter is compared with the Total Allowance (TA) for determination of instrument channel margin.

MEnvironmental Allowance (EA)

The change in a process signal (transmitter or process rack output) due to adverse environmental conditions from a limiting accident condition. Where appropriate, a value is explicitly noted. For functions not required to operate in an adverse condition, a value of zero is assigned. Typically this value is determined forom a conservative set of enveloping conditions and may represent the following:

a) Temperature effects on a transmitter, b) Radiation effects on a transmitter, c) Seismic effects on a transmitter, d) Temperature effects on a level transmitter reference leg, e) Temperature effects on signal cable insulation and f) Seismic effects on process racks.

Note that the Rosemount transmitter specifications identif a residual uncertainty that could exist following a seismic event. However, this seismic uncertainty has not been incorporated in the uncertainty calculations since TVA has committed to check/recalibrate these transmitters following a seismic event.

IMMargin The calculated difference (in % instrument span) between the TA and the CSA.

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IMNominal Trip Setpoint (NTS)

A bistable trip setpoint (analog function) or CPU trip output (digital function) in plant Technical Specifications. This val:ue is the nominal value to which the bistable is set, as accurately as reasonably achievable (analog function) or the defined input value for the CPU trip output setpoint (digital function).

• Normalization The process of establishing a relationship, or link, between a process parameter and an instrument channel.

This is in contrast with a calibration process. A calibration process is performed with independent known values, i.e., a bistable is calibrated to change state when a specific voltage is reached. This voltage corresponds to a process parameter magnitude with the relationship established through the scaling process.

A.normalization process typically involves an indirect measurement, e.g., determination of Steam Flow via the AP drop across a flow restrictor. The flow coefficient is not known for this condition, effectively an orifice, therefore a mass balance between Feedwater Flow and Steam Flow can be made. With the Feedwater Flow known, through measurement via the venturi, the Steam Flow is normalized.

• MPrimary Element Accuracy (PEA)

Error due to the use of a metering device, e.g., venturi, orifice, or elbow. Typically, this is a calculated or measured accuracy for the device.

MProcess Loop (.Instrument Process Loop)

The process equipment for a single channel of a protection function.

MProcess Measurement Accuracy (PMA)

Allowance for non-instrument related effects which have a direct bearing on the accuracy of an instrument channel's reading, e.g., temperature stratafication in a large diameter pipe, fluid density in a pipe or vessel.

IMProcess Racks The analog or digital modules downstream of the transmitter or sensing device, which condition a signal and act upon it prior to input to a voting logic system. For Westinghouse process systems, this includes all the equipment contained in the process equipment cabinets, e.g., conversion resistor, transmitter power supply, R/E, lead/lag, rate, lag functions, function generator, summator, control/protection isolator, and bistable for WCAP- 17044-N P . 11 December 2009 Revision 0

analog functions; conversion resistor, transmitter power supply, signal conditioning-AiD converter and CPU for digital functions. The go/no go signal generated by the bistable is the output of the last module in the analog process rack instrument loop and is the input to the voting logic. The CPU trip output signal is the input to the voting logic from a digital system.

IMR/E Resistance (R) to voltage (E) conversion module. The RTD output (change in resistance as a function of temperature) is converted to a process loop working parameter (voltage) by this analog module.

Westinghouse 7300 and Eagle-21 Process Instrumentation Systems utilize R/E converters for treatment of RTD output signals.

M R/I Resistance (R) to current (I) conversion module. The RTD output (change in resistance as a function of temperature) is converted to a process loop working parameter (current) by this analog module. Foxboro, Hagan and Westinghouse 7100 Process Instrumentation Systems utilize RiI converters for treatment of RTD output signals.

E Rack Calibration Accuracy (RCA)

The reference (calibration) accuracy, as defined by SAMA Standard PMC 20.1-19731] for a process loop string. Inherent in this definition is the verification of the following under a reference set of conditions: 1)

[p! [31 . .. [4]

conformity[, 2) hysteresis and 3) repeatability . The Westinghouse definition of a process loop includes all modules in a specific channel. Also, it is assumed that the individual modules are calibrated to a particular tolerance and that the process loop as a string is verified to be calibrated to a specific tolerance.

The tolerance for the string is typically less than the arithmetic sum or SRSS of the individual module tolerances. This forces calibration of the process loop without a systematic bias in the individual module calibrations, i.e., as left values for individual modules must be compensating in sign and magnitude.

For an analog channel, an individual module is typically calibrated to within ] with W the entire process loop typically calibrated to within [ ]'. For simple process loops where a power supply (not used as a converter) is the only rack module, this accuracy may be ignored. However, it is Westinghouse practice to include this accuracy for these simple loops as a degree of conservatism.

For a Westinghouse supplied digital channel, RCA represents calibration of the signal conditioning - AID converter providing input to the CPU. Typically there is only one module present in the digital process loop, WCAP- 17044-NP 12 December 2009 Revision 0

thus compensation between multiple modules for errors is not possible. However, for protection functions with multiple inputs, compensation between multiple modules for errors is possible. Each signal conditioning - A/D converter module is calibrated to within an accuracy of ax for functions with process rack inputs of 4 - 20 nA or 10 50 mA, or [ ] for RTD inputs.

M Rack Comparator Setting Accuracy (RCSA)

The reference (calibration) accuracy, as defined by SAMA Standard PMC 20.1-1973 N of the instrument loop comparator (bistable). Inherent in this definition is the verification of the following under a reference 2 131 14]

set of conditions: 1) conformity , 2) hysteresis and 3) repeatability . The tolerances assumed for the Watts Bar analog channels (based on input friom TVA) are as follows:

a.) Fixed setpoint with a single input - [ ] accuracy. This assumes that comparator nonlinearities are compensated by the setpoint.

b.) Dual input - an additional [ ] must be added for comparator nonlinearities between two inputs. Total [ ] accuracy.

In many plants, calibration of the bistable is included as an integral part of the rack calibration, i.e., string calibration. Westinghouse supplied digital channels do not have an electronic comparator, therefore no uncertainty is included for this term for these channels.

M Rack Drift (RD)

The change in input-output relationship over a period of time at reference conditions, e.g., at constant temperature. Typical values assumed for this parameter are [ ] span for 30 days for analog racks and [ ] ° for 90 days for digital racks.

• Rack Measurement & Test Equipment Accuracy (RMTE)

The accuracy of the test equipment (typically a transmitter simulator, voltage or current power supply, and DVM) used to calibrate a process loop in the racks. When the magnitude of RMTE meets the requirements of SAMA PMC 20.1-1973 15]it is considered an integral part of RCA. Magnitrudes in excess of the 10:1 limit are explicitly included in Westinghouse calculations.

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N Rack Temperature Effects (RTE)

Change in input-output relationship for the process rack module string due to a change in the ambient environmental conditions (temperature, humidity, voltage and frequency) from the reference calibration conditions. It has been determined that temperature is the most significant, with the other parameters being second order effects. For Westinghouse supplied process instrumentation, a value of

] is used for analog channel temperature effects and [ ]C is used for digital channels. It is assumed that the equipment will operate within +/-50'F of the temperature at which calibration was performed.

• MRange The upper and lower limits of the operating region for a device, e.g., for a Pressurizer Pressure transmitter, 0 to 3000 psig, for Steam Generator Level, 0 to 750 inches of water column. This is not necessarily the calibrated span of the device, although quite often the two are close. For further information see SAMA PMC 20.1-1.973[6.

• 2 Safety Analysis Limit (SAL)

The parameter value assumed in an accident analysis at which a reactor trip or actuation function is initiated.

MSensor Calibration Accuracy (SCA)

The reference (calibration) accuracy for a sensor or transmitter as defined by SAMA Standard PMC 20.1-1973 *. Inherent in this definition is the verification of the following under a reference set of

[2] [3] [4]

conditions: 1) conformity , 2) hysteresis and 3) repeatability . For Westinghouse supplied transmitters, this accuracy is typically [ ]'. This same value has been employed for the Rosemount transmitters.. Utilizing Westinghouse recommendations for RTD cross-calibration, this accuracy is typically p for the Hot Leg and Cold Leg RTDs.

MSensor Drift (SD)

The change in input-output relationship over a period of time at reference calibration conditions, e.g., at constant temperature. Typical allowance for a Westinghouse supplied transmitter is pc for 18 calendar months. For the Rosemount transmitters, a value of+.1.2% span has been used, which bounds the vendor specifications.

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INSensor Measurement & Test Equipment Accuracy (SMTE)

The accuracy of the test equipment (typically a high accuracy local readout gauge and DVM) used to calibrate a sensor or transmitter in the field or in a calibration laboratory. When the mnagnitude of SMTE meets the requirements of SAMA PMC 20.1-197315) it is considered an integral part of SCA, Magnitudes in excess of the 10:1 limit are explicitly included in Westinghouse calculations.

TVA's policy of using a 1:1 criteria at Watts Bar has been incorporated into this analysis for all functions except Containment Sump Level.

M Sensor Pressure Effects (SPE)

The change in input-output relationship due to a change in the static head pressure from the calibration conditions (if calibration is performed at line pressure) or the accuracy to which a correction factor is introduced for the difference between calibration and operating conditions for a AP transmitter. For Westinghouse supplied transmitters, a typical SPE value is [ ] with an allowance off ] variance fi'om calibration conditions (if performed at line pressure). If a correction is introduced, e.g., for calibration at atmospheric pressure conditions, it is assumed the correction factor is 1,C introduced.with an accuracy of For the Rosemount transmitters, the static pressure span effect is systematic and will be calibrated out for a given pressure. In addition, the static pressure zero effect will be calibrated out at the operating pressure.

Additional span and zero uncertainties due to pressure variations from the correction pressures are included in the uncertainty calculations.

G Sensor Temperature Effects (STE)

The change in iniput-output relationship due to a change in the ambient environmental conditions (temperature, humidity, voltage and frequency) from the reference calibration conditions. It has been determined that temperature is the most significant, with the other parameters being second order effects.

[]C For Westinghouse supplied transmitters, the temperature effect is typically with a maximum assumed change of +/-50'F from the calibration temperature. Rosemount temperature effects are based on the Roseiount specifications and the same temperature variation.

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MSpan The region for which a device is calibrated and verified to be operable, e.g., for a Pressurizer Pressure transmitter, 800 psig. For Pressurizer Pressure, considerable suppression of the zero and turndown of the operating range is exhibited.

MSRSS Square root of the sum of the squares, i.e.,

e= a2 +b2 +C2 as approved for use in setpoint calculations by ISA Standard S67.04-19871:'.

• Total Allowance (TA)

The absolute value of the calculated difference between the Safety Analysis Limit and the Nominal Trip Setpoint (SAL - NTS) in % instrument span. Two examples of the calculation of TA are:

M NIS Power Range Neutron .Flux - High SAL 118 % RTP NTS - 109 % RTP TA 9 % RTP If the instrument span 120 % RTP, then TA = (9 % RTP)(100 % span)! (120 % RTP) = 7.5 % span N PressurizerPressure- Low SAL 1910 psig NTS - 1970 psig TA 60 psig If the instrument span 800 psig, then TA = (60 psig)(1(00 % span)/(800 psig) =7.5 % span WCAP- 17044-NP 16 December 2009 Revision 0

3.3 Cross Reference - SAMA PMC 20.1-1973 and ANSIiSA-S1.1i-1979 SAMA Standard PMC 20.1-1973, "Process Measurement & Control Terminology" is no longer in print and thus is unavailable from SAMA. It has been replaced by ANSI/ISA S51.1-1979, "Process Instrumentation Terminology" and is available from the Instrument Society of America.

Noted below is a cross reference listing of equivalent definitions between the two standards for terms used in this documnent. Even though the SAMA standard is no longer available, Westinghouse prefers and continues to use the SAMA definitions.

SAMA ISA Reference Accuracy' Accuracy RatingN Conformityr2j Conformity, Independent~lg 3

Hysteresis* ' Hysteresis""'

Repeatability 4: Repeatability""1 Test Cycle"4 Calibration Cyclei""

Test Procedures'i* Test Procedures':2]

Range&6) Range"[3' 3.4 References / Standards (1) Scientific Apparatus Makers Association Standard PMC 20.1-1973, "Process Measurement & Control Terminology," p 4, 1973.

(2) I[bid., p 5.

(3) Ibid., p 19.

(4) Ibid., p 28.

(5) Ibid., p 36.

(6) Ibid., p 27.

(7) Instrument Society of America Standard S67.04-1987, "Setpoints for Nuclear Safety-Related Instrumentation," p 12, 1987.

(8) Instrument Society of America Standard S51.1-1979, "Process Instrumentation Terminology," p 6, 1979.

(9) Ibid., p 8.

WCAP- 17044-NP 17 December 2009 Revision 0

(10) Ibid., p 20.

Ibid., p 27.

Ibid., p 33.

(13) ibid.. p 25.

3.5 Methodology Conclusions The Westinghouse setpoint methodology results in a value with a 95 % probability. Analog RD and SD are established based on a survey of reported LERs, vendor specifications, and Westinghouse experience, digital RD is based on system design, and PMA terms are considered conservative values.

WCAP-1I 7044-NP~ 18 December 2009 Revision 0

TABLE 3-1.

POWER RANGE, NEUTRON FLUX - HIGH AND LOW SETPOINTS Parameter Allowance*

ac Process Measurem ý1 L

+~nA r'lox

" L'. ýý.Y a*c L

Primary Element Accuracy I

Sensor Calibration Accuracy I pac Sensor Pressure Effects Sensor Temperature Effects

]a.c Sensor Drift I fpa Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Comparator One Input Rack.Temperature Effects Rack Drift In percent span (120 % Rated Thermal Power)

Not processed by Eagle-21 racks.

TVA Sensor Tag #s NMD-92-NE41-D, 42-E, 43-F, 44-G L

Channel Statistical Allowance .

Ic WCAP- 17044-NP 1.9 December 2009 Revision 0

TABLE 3-2 POWER RANGE, NEUTRON FLUX - HIGH POSITIVE RATE Parameter Allowance!

Process Measurement Accuracy L I Primary Element Accuracy L

Sensor Calibration Accuracy I

ax Sensor Pressure Effects Sensor Temperature Effects aXc I I Sensor Drift K ]

axc Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Comparator One input Rack Temperature Effects Rack Drift In percent span (120 % Rated Thermal Power)

Not processed by Eagle-21 racks.

TVA Sensor Tag #s NMID-92-NE41.-D, 42-E, 43-F, 44-G WCAP- 17044-NP 20 December 2009 Revinin 0

TABLE 3-2 (continued)

POWER RANGE, NEUTRON FLUX - HIGH POSITIVE RATE Channel Statistical Allowance--

L I ax WCAP- 17044-N P 21 December 2009 Revigioin 0

TABLE 3-3 INTERMEDIATE RANGE, NEUTRON FLUX Calculation 2-NMND-092-0131 performed by TVA WCAP- I7044-N P 22 December 2009 Revision 0

TABLE 3-4 SOURCE RANGE, NEUTRON FLUX Calculation 2-NMD-092-0131 performed by TVA WCAP- 17044-NP 23 December 2009 Revision 0

TABLE 3-5 OVERT EMPERATURE AT Parameter Allowance*

. a,C r- -'

Process Measurement Accuracy a,C Primary Element Accuracy Sensor Calibration Accuracy

[ ] ae

[j .1aQ Sensor Measurement & Test Equipment Accuracy

[ P.C-Sensor Pressure Effects Sensor Temperature Effects I

axc Sensor Drift

]a,C Environmental Allowance Bias Rack Calibration Accuracy a~c L I WCAP- I 7044-N P 24 December 2009 Revision 0

TABLE 3-5 (continued)

OVERTEMPERATURE AT Parameter Allowance*

Rack Measurement & Test Equipment Accuracy I

a,c Rack Temperature Effects L

Rack DriftF ac

.1a'C In percent AT span (Tavg - 100' F, Pressure - 800 psi, Power - 150 % RTP, AT - 91.2°F, Al - +/-60 %AI)

See Table 3-22 for gain and conversion calculations

1. Number of Hot Leg RTDs used

1. 1. Number of Cold Leg RTDs used TVA Sensor Tag #'s NIS NMD-92-NE4I-D, 42-E, 43-F, 44-G Pressure PT-68-322G, 323F, 334E, 340D Temperature TE-68-2)B 1, -21B2, -21B3, -14A, -148, -25131, -25B2, -251B3,

-37A, -371, -44B1, -44B2, -44B3, -56A, -568, -67B1,

-67B2, -67B3, -79A, -79B.

WCAP- 17044-NP 25 December 2009 Revision 0

TABLE 3-5 (continued)

OVERTEMPERATURE AT Channel Statistical Allowance WCAP- 17044-NP 26 December 2009 Revision 0

TABLE 3-6 OVERPOWER AT Parameter Allowane*~

Process Measurement Accuracy a,c Primary Element Accuracy Sensor Calibration Accuracy I IS Sensor Measurement & Test Equipment Accuracy

[ I a Sensor Pressure Effects Sensor Temperature Effects Sensor Drift

[ I IS Environmental Allowance Cable IR (0.46°F per TVA letter No. WBT-TVA-0848)

Bias Rack Calibration Accuracy I~

F WCAP- 17044-N P 27 December 2009 Revision 0

TABLE 3-6 (continued)

OVERPOWER AT Parameter Alowance*

Rack Measurement & Test Equipment Accuracy I I alc aXc Rack Temperature Effects i ]

Rack Drift U.X LF ]

• In percent AT span (Tavg - 100 'F, Power - 150 % RTP, AT - 91.2 .F)

• • See Table 3-23 for gain and conversion calculations 4 Number of Hot Leg RTDs used

1. 1. Number of Cold Leg RTDs used Channel Statistical Allowance =

• I.e, WCAP- 17044-NP 28 December 2009 Revision 0

TrABIE 3-7 PRESSURIZER PRESSURE - LOW AND HIGH REACTOR TRIP Parameter Allowance*

Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (800 psi)

Westinghouse Sensor Tag #'s: 2PT-455, 2PT-456, 2PT-457, 2PT-458 TVA Sensor Tag #'s: 2-PT-68-322-G, 2-PT-68-323-F, 2-PT-68-334-E, 2-PT-68-340-D L

Channel Statistical Allowance I

aXc WCAP-1 7044-NP 29 December 2009 Revision 0

TABLE 3-8 PRESSURIZER WATER LEVEL - HIGH Parameter Allowance*

K Process Measurement Accuracy Iac Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (100 % of span)

TVA Sensor Tag #'s 2-LT-68-320-F, 335-E, 339-D Channel Statistical Allowance =

Ia WCAP- 17044-N P 30 December 2009 Revision 0

TABLE 3-9 REACTOR COOLANT FLOW - LOW REACTOR TRIP Parameter Allowance*

Process Measurement Accuracy 8,C I ],c Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects

[ a~c Sensor Temperature Effects a,c Sensor Drift

[ ]ac Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift ac

• In percent flow span (120 % Thermal Design Flow). Percent AP span converted to flow span via Equation 3-24.8, with iFmax =-120 % and FN = 90 %, M value = 1.06.

All values are considered conservative due to the use of 120% Thermal Design Flow and an M value of 1.06.

WCAP- I7044-N P 31 December 2009 Revision 0

TABLE 3-9 (continued)

REACTOR COOLANT FLOW -.LOW REACTOR TRIP Westinghouse Sensor Tag #: 2FT-414, 2FT-415, 2FT-416, 2FT-424, 2FT1--425. 2FTF-426, 2FT-434, 2FT-435, 2FT-436, 2FT-444, 2FT-445, 2FT-446 TVA Sensor Tag #: 2-FT-68-6A-D, 2-FT-68-6B-E, 2-FT-68-6D-F. 2-FT-68 -29A-D, 2-FT-68-29B-E, 2-FT-68-29D-F, 2-FT-68-48A-D, 2-FT-68-48B-E, 2-FT-68-48D-F, 2-FT-68-71A-D, 2-FT-68-71B-E, 2-FT-68-71 D-F Chanmel Statistical Allowance =

E I ,c WCAP- 17044-NP 32 December 2009 Revision 0

TABLE 3-10 STEAM GENERATOR WATER LEVEL - LOW-LOW (INSIDE CONTAINMENT)

Parameter Allowance*

Process Measurement Accuracy

[-]ae Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Random Bias Sensor Temperature Effects Sensor Drift Environmental Allowance Temperature Effects ONLY, no Radiation Effects Reference Leg Heatup TTD reset - Incorporated into deadband (3.5 %)

Cable IR Rack Calibration A.ccuracv Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (100 % span)

Westinghouse Sensor Tag # 2LT-517, 518, 519, 527, 528, 529, 537, 538, 539, 547, 548, 549 TVA Sensor Tag# 2LT-3A42-G, 39-F, 38-E, 55-G, 52-F, 51-E, 97-G, 94-IF, 93-I), 110-G, 107-IF, 106-E WCAP- 17044-NP 33 December 2009 Revision 0

TABLE 3-10 (continued)

STEAM GENERATOR WATER LEVEL - LOW-LOW (INSIDE CONTAINMENT)

Channel Statistical Allowance = Steam Generator Water Level - LOW-LOW a,c WCAP- 17044-N P 34 December 2009 Revision 0

TABLE 3-10a STEAM GENERATOR WATER LEVEL - LOW-LOW (OUTSIDE CONTAIN MENT)

Parameter Allowance*

K ac Process Measurement Accuracy a,c Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Random Bias Sensor Temperature Effects Sensor Drift Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (100 % span)

Westinghouse Sensor Tag # 2LT-517, 518, 519, 527, 528, 529, 537, 538, 539. 547, 548, 549 TVA Sensor Tag # 2LT-3-42-G, 39-F, 38-E, 55-G, 52-F, 51-E, 97-G, 94-F, 93-D, 110-G, 107-F, 106-E WCAP- 17044-NP 35 December 2009 Revision 0

TABLE 3-1.0a (continued)

STEAM GENERATOR WATER LEVEL - LOW LOW (OUTSIDE CONTAINMENT)

Channel Statistical Allowance = Steam Generator Water Level - LOW-LOW L I WCAP- 17044-N P 36 December 2009 Revision 0

TABLE 3-11.

UNDERVOLTAGE Calculation 2-27-068-0031 performed by TVA WCAP- 17044-NP 37 December 2009 Revision 0

TABLE 3-12 UNDERFREQUENCY Calculation 2-81-068-0031 performed by TVA WCAP- 17044-NP 38 December 2009 Revision 0

TABLE 3-13 CONTAINMENT PRESSURE - HIGH, HIGH-HIGH Parameter Allowance*

Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift Environmental Allowance - Radiation Effects - Treated as a Bias Cable IR Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (17 psi)

Westinghouse Sensor Tag #: 2PT-934, 2PT-935, 2PT-936, 2PT-937 TVA Sensor Tag #: 2-PDT-30-42-G, 2-PDT-30-43-F, 2-PDT-30-44-E, 2-PDT-30-45-D Channel Statistical Allowance WCAP- 17044-NP 39 December 2009 Revision 0

TABLE 3-14 PRESSURIZER PRESSURE - LOW, SAFETY INJECTION Parameter Allowance*

ac Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift Environmental Allowance Radiation Effects - treated as a Bias Temperature Effects - treated as a Bias Bias Cable IR - per TVA Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (800 psi)

Westinghouse Sensor Tag #'s: 2PT-455, 2PT-456, 2PT-457, 2PT-458 TVA. Sensor Tag #'s: 2-PT-68-3221-G, 2-PT-68-323-F, 2-PT-68-334-E, 2-PT-68-340-D Channel Statistical Allowance =

WCAP- 17044-NP 40 December 2009 Revision 0

TABLE 3-15 STEAMLINE PRESSURE - LOW Parameter Allowance*

Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift Environmental Allowance Temperature Effects - treated as a Bias Bias Cable IR Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (1300 psi)

Westinghouse Sensor Tag #: 2PT-51.4, 2PT-515, 2PT-516, 2PT-524, 2PT-525, 2PT-526, 2PT-534, 2PT-535, 2PT-536, 2PT-544, 2PT-545, 2PT-546 TVA Sensor Tag #: 2-PT-1-2A-D, 2-PT-1 -2B-E, 2-PT-1-5-G, 2-PT-1-9A-D, 2-PT-1-9B-E, 2-PT-1-12-F., 2-PT 20A-D, 2-PT-1-20B-E, 2-PT-1-23-F, 2-PT-1-27A-D. 2-PT-1-27B-E, 2-PT-1-30-G WCAP- 17044-NP 41 December 2009 Revision 0

TABLE 3-15 (continued)

STEAMLINE PRESSURE - LOW Channel Statistical Allowance =

I Steam Line Break Outside Containment c

Steam Line Break Inside Containment WCAP- 17044-N P 42 December 2009 Revision 0

TABLE 3-16 STEAM GENERATOR WATER LEVEL - HIGH-HIGH Parameter Allowance*

3.C Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Random Bias Sensor Temperature Effects Sensor Drift Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (100 % span)

Westinghouse Sensor Tag #2LT-517, 518, 519, 527, 528, 529, 537, 538, 539, 547, 548, 549 TVA Sensor Tag # 2LT-3-42-G., 39-F, 38-E, 55-GQ 52-F, 51-E, 97-G, 94-F, 93-D, I 10-G, 107-F, 106-E Channel Statistical Allowance (sign convention denotes direction only) .

WCAP- 17044-NP 43 December 2009 Revision 0

TABLE 3-17 NE( ;ATIVE STEAMLINE PRESSURE RATE - HIGH Parameter Allowance*

ac Process Measurement Accuracy Primary Element Accuracy L

Sensor Calibration Accuracy Sensor Pressure Effects L

Sensor Temperature Effects I~

a,c Sensor Drift Environmental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift In percent span (1300 psi)

Westinghouse Sensor Tag #: 2PT-514, 2PT-515, 2PT-516, 2PT-524, 2PT-525, 2PT-526, 2PT-534, 2PT-535, 2PT-536, 2PT-544, 2PT-545, 2PT-546 TVA Sensor Tag #: 2-PT-1-2A-D, 2-PT-1-2B-E, 2-PT-I-5-G, 2-PT-1-9A-D, 2-PT-1-9B-E, 2-PT-I-12-F, 2-PT 20A-D, 2-PT-1i-20B-E, 2-PT- 1-23-F, 2-PT- 1-27A-D, 2-PT-1-27B-E, 2-PT-I G Channel Statistical Allowance =

L WCAP- 17044-NP 44

]a,,.

December 2009 Revision 0

TABLE 3-1.8 RWST LEVEL - LOW Parameter Allowance*

a.c Process Measurement Accuracy Primary Element Accuracy Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects Sensor Drift Enviromnental Allowance Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift

• In percent span (387 inH 20 - 100 % span)

Westinghouse Sensor Tag #: 2LT-913, 2LT-914, 2LT-915, 2LT-916 TVA Sensor Tag #: 2-LT-63-50-D, 2LT-63-51 -E, 2LT-63-52-F. 2LT-63-53-G Channel Statistical Allowance =

K WCAP- 17044-N P 45 December 2009 Revision 0

TABLE 3-1.9 CONTAINMENT SUMP LEVEL - HIGH/AUTO SWITCHOVER Parameter Allowance*

fl,c Process Measurement Ac curacy L

Primary Element Accuracy I

Sensor Calibration Accuracy Sensor Measurement & Test Equipment Accuracy Sensor Pressure Effects Sensor Temperature Effects I ]a~c Sensor Drift I

Environmental Allowance aIC Bias

(( I L.C IaC I

Rack Calibration Accuracy Rack Measurement & Test Equipment Accuracy Rack Temperature Effects Rack Drift lIn percent span (100 % span)

TVA Sensor Tag #s 2-LT-63-180-D, 18 1--E, 182-F, 183-G Channel Statistical Allowance .

I WCAP- 17044-NP 46 I.C December 2009 Revision 0

TABLE 3-20 VESSEL AT EQUIVALENT TO POWER Parameter Allowance*

axc Process Measurement Accuracy aXc Primary Element Accuracy Sensor Calibration Accuracy

[. ]ac Sensor Measurement & Test Equipment Accuracy

[ I a Sensor Pressure Effects Sensor Temperature Effects Sensor Drift I I ac Environmental Allowance Rack Calibration Accuracy ac I ]

Rack Measurement & Test Equipment Accuracy aC I ]

Rack Temperature Effects I I Rack Drift a,c t- ]

in percent span (Power - 150 % RTP, AT - 91.2°F)

See Table 3-23 for gain and conversion calculations WCAP-17044-NP 47 December 2009 Revision 0

TABLE 3-20 (continued)

VESSEL AT EQUIVALENT TO POWER

1. Number of Hot Leg RTDs used

1. 1. Number of Cold Leg RT.Ds used TVA Sensor Tag #'s - See Table 3-5 Channel Statistical Allowance.

WCAP- 17044-NP 48 December 2009 Revision 0

RESTINýOTUSENGN-PROPRIETARYELRS3 PAGE 55 TABLE 3-21 REACTOR TRIPSYSTEM / ENGINEERED SAFETY FEATURES ACTUATION SYSTEM CHANNEL ERRORALLOWANCES WATTSBARUNIT2 SENSOR iNSTRUMENTROE I 2 4 5 - 7 5 8 N I1 12 IT 14 15 I6 IT U IS MEASUREMENT ENVIRON- MEASUREMENT PROCESS PRIM-AY &TEST MENTAL &TEST COM PRATOR SAFETY CHANNEL PRONTECTINCHAMNEL MEASUREMENTELEMENT CALIBRATION EQUIPMENTPRESSURE TEMPERATURE ALLOAMNCE CALIBRATIONEQUIPMENT SETTING TEMPERATURE ANALYSIS AULLOABLE TRIP TOTA. STUISTICAL ACCURACY ACCURACYACCURACY ACCURACY EFFECTS EFFECTS DRIFT OFRBIS ACCURACY ACCURACY ACCURACY EFFECTS wn URMIT VALUE SETPOINT ALUANCE ALUMANCE MARGIE I , EER RANGE.NEUTRON FLUX HIGH SNTPOT 1A I5 % RTP II4 %RTP INRIP 1.5 I 2 PUYWERRASGE.NEUTRON FLUX-LOWASETPFNYT IA0 NRIP 27DARNP 25%ASP 2 3 POVARERANGE,NEUTRONFLUXHIGH POSUTIE RATE OS (4) 6.3%ARTPPASEC 50%RTPnSEC - 3 4 INTERMEDIATERANGE NEUTRON ALUX ]9) (B) I (9) 5 NONRCE RANSGE`

NEUTRON FLURX IPI 1% - N N UUEUTEMPERATUREUT FUNCTIN (13) FUNcoUN (14) FUNCTON (4) &D 6 UTCCHANEEL 'ID2%ITSPN N TAVGCHANNEL pRESSURIZER PRESSURECHANNEL NgCHANNEL 7 OVERUOWER UT I]FUNCTION(13) FUNCTION (14) FUNCTION (14) ES UTACHLNEL *I0.ATSPAN TAVCCHANNEL III I i PRESSURZEPRESSURE- LOW, REACTOR TRIP ISI9PSIG 1964.8 PSIG 1970PSIG 75 B PRESSUPJZERPRESSURE-HIGH 2445PSKS 2M2 PSIG KIMSPSIG .59 IS PRESSURIZEWAUISR LEVEL -HIGH iI isUN -i.TIN tI 11 REACTONEANER AOT FLUS-LOMAEUCSSR TRIP 87%FLOW 89T%REOW 9%FLOW EN 11 12 UoSAN STEAMGENERATORWATERLEVEL-ELOW.OW 16ASIN

%SAN STAIN SAN IS. 12 IKITSSI ]TI]NTI 13I STEMA GENERATORWATER LEVELER- L DWN5 USPAN IR4IN 17"0% SPAN 1AU 13 INSIDE CONTAINMENT I 14 UNAERYALTAUE -REP (9) - 15) RI RI RI (R - 1 RI (9) (9) (9) R9) (B) N, 15I UNDERFRESENCY-RCP (9) - (9) (9) ( ) (9) - (9) I9) (9) (9) (R) ()

(B - I5 ND ES II.-NA 16 CONTAINMENI PRESSURE - HIGH F2 PSS SOFS 1.5`SG 1F IS t7 CONTAINMENTPRENSURE -HUGAIGH 3SPSIG 2.9PSIG 2E8 PSG 4I 18 PRESSURIER PRESSURE -LOW. SI I7MPSIG ,PS IIW.8PI1 1I70 SI2 IS 19 STNEALINE PRESSURE - LOW 431PSIG SSENPS-G 675PSIG 1.2 IS IS.- LU 1, I0I-N) STYANLINE PRESSURE -LOW 4%9 PSIG 69SE PSIG 675FSIG 11. 20 (St.. LIeAreak InsUSLESUS5WIG 21 NEGATIVE STEAMLINEPRESSURE RATE - HIGH RI S0B PSI INw PSI 21 2 STEMEGENRATURWUTER LEEL - HIGH-HIG 99.4%SPAN (45) 831%SPAN 824 % SPAN 22 S VESSELUATEUNE ALENT TO E H HI ASP MENIN2.6

%RTP UTUVOS*b6M RCSNL-p SoInt 23 TYCHANNEL RTP 24 RWIST- LEVELLOW I SANN .ANw- '2I SNPM 24 25 CONTAINMENT SUMPN EVELL-AHIGGl E NSPAN ISNINN1MA N%MSAN 16.1 2S AUTOSW"TCHGVER IL I ,

T4.ASNOTED INTABLES1-I OFTEETECIICALSPECIRCATIR"S nR I ]" AL SUUMEGNE EFFECT I. ALLVALUESINPENCENTOFSPAN. 5 I I 27. I3. SEISMICEFFECT-PUAROlEDBYWA-TREATEDAUASIAAS Z ASNOTEF'RNFUURP ATUNSUTAýLE15.1-3OFTHEFSR. 16I r S8NNOTUNED 3EASCALCULATED MSING MHEMETHODOLOGY NOTEDON TABLE 4-2OFTHIS REPRT 6. NOTSED 29. ROT USED 40 NUTUNED 4- 1 I" IN [ ]" 3D.I I" 41. I 0" E is. [31 42. [

-PROVIDED UVA AND By TREATEDASABAS 32 I I 44. I [

I" DEGRADATON RESISTANCE 2.ORCALEINSULATION NOT USEDIN THE SAFETY ANALYSIS 21. 1 r, " I SCALCULAnONSPERFOAMEDByIVA U4NOT USED NOTUSED 45. MAXIMUMNREAULE INDICATED LEVEL 15.1 1- D. I IU.E, SI,INCOREIEXCORE f(AICOMPARISON ASOTED IN PLANTTECHNICAL SPECIFICATIONS 24 I L TA.I I3 12.[ " 25. 1 37.1 13.ASNOTED FOR INFORMATION INFIGURE 151-1OFTHE FEAR

TABLE 3-22 OVERTEMPERATURE AT CALCULATIONS 0 The equation for Overtemperature AT:

OvertemperatureAT ( 1 T) <

I*~ +ý "SS ~ +

ATo. K, - K, ( I . TS)[lT - T'] + K 3 (P - P') - fI(A/)

I +1+

I K, (nominal) 1.16 As noted in the Technical Specifications a~c K, (max) I K2 - 0.0183 /iF K3 =- 0.000900 / psi Vessel TI, . 618.6 OF Vessel Ic 557.8 OF Al gain . 1.96 % (for Al > +10 %)

• Full power AT calculation:

AT span = [ I]',Co AT span pwr = 150 % RTP Process Measurement Accuracy Calculations:

L I.C I a.C L I K I a.C WCAP- 17044-N P December 2009 Revision 0

TABLE 3-22 (continued)

OVERTEMPERAT URE AT CALCULATIONS Al - Incore / Excore Mismatch a~c r

Al - Incore Map Delta-I Uncertainty a,c K

• As noted for information in Surveillance Item SR 3.3.1.3 of the Technical Specifications.

• Pressure Channel Uncertainties a.C Gain-I ]

a,c SCA=

SMTE STE =

SD axc RCA=

RMTE:

RTE =

RD WCAP- 17044-N P 51 December 2009 Revinion 0

TABLE 3-22 (continued)

OVERTEMPERATURE AT CALCULATIONS Al Channel Uncertainties a.c Gain =

I I

~I.c RCA-RMTE -

RTE =

RD =

• Total Allowance

~i.c WCAP- 17044-NP 52 December 2009 Revision 0

TABLE 3-23 OVERPOWER AT CALCULATIONS The equation for Overpower AT:

Overpower AT (I + T <_

r3 SL.T-Ko lIT -T"-f2 (AI)~

K4 (nominal) 1.10 As noted in the Technical Specifications K 4 (max) .a, K5 = 0 for decreasing average temperature K5 = 0.02 / °F for increasing average temperature K6 - 0.00162 / OF Vessel TH 61.8.6 OF Vessel Tc

• 557.8 OF

1. Full power AT calculation:

AT span . I aC AT span pw.r = 150 %RTP L

1. Process Measurement Accuracy Calculations:

aC I

K I a,C ac I

• Total Allowance ac 53 December 2009 17044-NPP WCAP- I17044-N 53 Revigion 0

TABLE 3-24 AP MEASUREMENTS EXPRESSED IN FLOW UNITS The AP accuracy expressed as percent of span of the transmitter applies throughout the measured span, i.e.,

+1.5 % of 100 inches AP = +/-1.5 inches anywhere in the span. Because F12 = f(AP), the same cannot be said for flow accuracies. When it is more convenient to express the accuracy of a transmnitter in flow terms, the following method is used:

(FN)2 = A Pv where N Nominal Flow 2

FNa FNv = aA PN aA PN thus a FNv -Eq.2 3-24.1 Error at a point (not in percent) is:

aF,v 2(P,v a A P'.v Eq. 3-24.2 2

FN (,FN)' 2A P, and A PN (F 2, Eq. 3-24.3 A Pmnax (Fniax )

where max = maximum flow and the transmitter AP error is:

DA P AP,(100) percent error in Full Scale AP (%c FS AP) Eq. 3-24.4 APmx therefore:

%d°A-ctSAPi A PrnNaK 0 0 1 . /FSAPI FF. ]2 Eq. 3-24.5 EFN2, 2A Pmnax [_ 1 2

(2)(100) j WCAP- 17044-N P 54 December 2009 Revision 0

TABLE 3-24 (continued)

AP MEASUREMENTS EXPRESSED IN FLOW UNITS Error in flow units is:

P F= [%FSAP TF,, Eq. 3-24.6 (2)(l 00) F Error in percent nominal flow is:

rr (10()r pe =  %'spanis Eq. 3-24.7 Error in percent full span is:

F %'7FSAP] ~a]2 10 c)F , ( 1 0 0)

Eq. 3-24.8

%L

%FSAP][I4Vax Eq. 3-24.8 is used to express errors in percent fill span in this document.

WCAP- 17044-N P 55 December 2009 Revision 0

4.0 APPLICATION OF THE SETPOINT METHODOLOGY 4.1 History The original "Vendor" or "Custom" Technical Specifications did not allow for rack drift in setpoint requirements. This type of instrument Technical Specification contains only one number, the Nominal Trip Setpoint (NTS). If, during the surveillance interval associated with a function, the channel setpoint drifted non-conservatively past the NTS, the plant was required to file a Licensee Event Report (LER), or equivalent, in addition to correcting the instrunmentation.

In November 1974ý the D. C. Cook Unit I Standardized Technical Specifications were issued by the NRC. Included in these specifications was a new concept, the AV. Exceeding the NTS while remaining within the bounds of the AV was not considered a reportable event. With the advent of the AV, it was no longer necessary to set the bistable as far into the operational margin. At this time, the AV included an allowance for rack drift (and only rack drift).

In November, 1975. the original version of Regulatory Guide 1.105 was issued for comment. The Regulatory Guide addressed NRC concerns associated with the frequent drift of protection system setpoints past the NTS limit. The NRC defined version of the AV in this Regulatory Guide allowed for a certain amount of "drift". In 1976, Regulatory Guide 1.105 Rev. I was issued noting minor changes.

This was the first opportunity for many plants to include uncertainties in the calculation of an AV.

In 1.977, the NRC requested that several utilities provide responses to questions concerning protection function setpoint methodology. In order to answer these questions, Westinghouse expanded their setpoint related efforts. Westinghouse also changed sunmmation techniques; from arithlnetic summation to SRSS.

In June of 1978, D. C. Cook Unit 2 was the first plant to implement the new methodology and responded to the NRC request for information relative to details of the Westinghouse Setpoint Methodology. Salem Unit I and North Anna Unit 1 soon followed.

In 1981, the V. C. Summer setpoint study was formally reviewed by the NRC. During this process, Westinghouse proposed the five column methodology which was subsequently approved, containing provisions which would provide some operating flexibility. If a plant identified that an AV had been exceeded, the five column methodology included provisions which, in some cases, could eliminate the need for a formal LER. NUREG 0717 Supplement No. 4, August, 1982, documents the NRC Safety Evaluation Report (SER) which approves the Westinghouse methodology.

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In 1983 10 CFR 50.73 was issued by the NRC. This regulation changed the filing requirements associated with an LER. According to 10 CFR 50.73, filing an LER would not be required as a response to the loss of a single channel. Only as a result of the loss of a function would an LER be required. This inportant position change meant, among other things, that benefits associated with the Westinghouse five column methodology were no longer necessary to avoid filing an LER.

Revision 2 of Regulatory Guide . 105 was issued in February, 1986. [t used the calculational methods associated with 1.105 Rev. I and it endorsed the Instrument Society of America (ISA) standard ISA-S67.04-1982. This standard was created to address the establishment and maintenance of setpoints for safety-related instrument channels.

4.2 The Allowable Value In History Originally, in the "Vendor" or "Custom" Technical Specifications, the NTS was the only value noted and it was defined as the absolute limit for determination of reportablility. With only one value noted with either > or _<inequalities, the plant had no choice but to use a bistable field setting conservative with respect to the value in the Technical Specifications. This was necessary to account for drift and calibration errors. This resulted in the loss of some operational margin, for example:

NIS Power Range - High NTS = <1.09 %.RTP Bistable = 108 % RTP Operating Margin Loss - 1% R'P As noted, Regulatory Guide 1.105 Rev. 1 represented the first opportunity for many plants to include uncertainties in the calculation of an AV. With NRC acceptance of the AV concept, it was no longer necessary to set the bistable into the operational margin.

Unfortunately, the only uncertainty term that could be used in the calculation of this AV was the rack drift term. No allowances were made for calibration errors. The 1981 NRC review of the V. C.

Summer setpoint study resulted in several modifications to the AV calculation which incorporated calibration errors. It was during this review that the AV took on its current shape.

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While there are many different industry definitions used for the AV., the Westinghouse version has always been limited to process rack errors. The following derivation has been based on the Westinghouse methodology and is accepted in the V. C. Summer Safety Evaluation Report (SER). The Westinghouse determined AV provides the utility with operational flexibility, the conservatism associated with a 95 % probability calculation, and the NRC acceptance precedent.

With the NRC approval of the Westinghouse setpoint approach in the V. C. Summer Technical Specifications, it became feasible to have an "as left" setpoint equal to the NTS. This was made possible by permitting the AV to include rack drift, calibration and M&TE uncertainties. When the uncertainty calculations have sufficient margin to permit it. the difference between the AV and the NTS is large enough to encompass all three uncertainties. if, on the other hand, the constraints represented by Safety Analysis and by operational considerations are such that there is little tolerance for channel uncertainty, the difference between the NTS and the AV is determined considering additional uncertainty terms, as described below.

Provisions in the methodology include a series of equations used to determine the most acceptable AV.

These "trigger" calculations are described below.

E Trigger Values for a Single Input Function When determining the AV for a single input function, Westinghouse evaluates two different scenarios and uses the most limiting, or conservative, value calculated. The trigger variables used in this calculation are T, and T 2. The smaller of the two trigger values is the one which defines the function's AV. In other words, AV = NTS + Minimum of {T1, T 2 The first trigger value is defined as follows:

IM T,= RCA + RMTE + RCSA + RD Eq. 4.1 The equation. for T, is a simple arithmetic combination of the rack uncertainties for which surveillance is performed on a monthly or quarterly basis. Note that in plants with digital process instrumentation, RCSA will be [ ] since this is a value held in memory for which

]*c with its setting. This calculation accounts for operational concerns (equipment design and calibration procedure criteria) and is based on several assumptions:

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1) the "as left" condition was at the maximum allowed by the calibration procedure,

2) the M&TE uncertainty was at the maximum allowed and

3) a process loop found within this value is operating within the drift tolerance.

This scenario (calibration at its allowed extreme with the test equipment at their allowed extremes) would not be considered a "nominal" condition, but would be considered an "allowed" condition.

The second trigger value is defined as follows:

12 1 = TA - {(PMA) 2+(PEA)-+(SCA+SMTE+SD) 2 +(SPE)2+(STE) 2+(RTE) 2}1(K - EA Eq. 4.2 Note that the TA calculation is detailed in Section 3.0 of this report. T2 is determined by an evaluation of what uncertainties the Safety Analyses can tolerate, based on the TA. This calculation accounts for the.

channel flexibility associated with the channel's SAL assuming that:

1) the sensor is calibrated in an acceptable manner,

2) the sensor drifts in a random manner and

3) the parameters not evaluated on a periodic basis also experience random variations.

This calculation is basically the subtraction of the above noted parameters from the TA. What remains is the acceptable RD and calibration allowance.

ESTrigger Values for a Multiple Input Function When determining the AV for a multiple input function, Westinghouse evaluates two different scenarios and uses the most limiting, or conservative, value calculated. The trigger variables used in this calculation are T 2 and T3. Here again, the smaller and therefore more conservative of the two trigger values is the one which defines the function's AV.

AV = NTS +/- Minimum of {T2 ,T 3}

The first of these two trigger values, T 2 is essentially the same as Eq. 4.2, and defined as follows:

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ST2 = TA - {(PMA)2+(PEA) 2+(SCAI+SMTEI+ SDi)+(SPEI)'2(STE,)2+

(SCA 2+SMTE,,+SD 2)2+(SPE-,)'+(STE 2)4+(RTE) 2}' - EA Eq. 4.3 Note that the TA calculation is detailed in Section 3.0 of this report and the subscripts I and 2 indicate the different channels. In this case, the equation utilizes the entire range of sensor terms (SCA, SMTE, SD, STE, SPE) for more than one sensor. Each sensor is an independent device and its uncertainties are, therefore, treated by SRSS. T2 is determined by an evaluation of what the Safety Analyses can tolerate, based on TA. This calculation allows for the channel flexibility associated with multiple sensors and the channel's Safety Analysis assuming that:

1) the sensors are calibrated in an acceptable manner,

2) the sensors drift in a random manner and

3) the parameters not evaluated on a periodic basis also experience random variations.

This calculation is basically the subtraction of the above noted parameters (and the EA) from the TA. What remains is the acceptable rack drift and calibration allowance.

The second trigger value for a multiple inptit function, T 3 is defined as follows:

• 1 T3 = {(RCA1+RMTE1 +RCSA1 +RD1) 2 + (RCA 2+RMTE 2+RCSA 2+RD 2)}" Eq. 4.4 As in the T 2 equation, the subscripts I and 2 in T3 indicate the two different input channels. Note that in plants with digital process instrumentation, RCSA will be [ ] since this is a value held in memory for which [ pc with its setting. T3 is the evaluation foro the operational side for multiple input protection functions. An operational evaluation accounts for equipment design and for calibration procedure criteria.

Thus three equations T I , T-, and T3 are used to calculate the AV. T, is used for a single input protection function and evaluated from the operational side. J'2 is used for either a single or multiple input protection function and evaluated from the Safety Analyses side. T3 is used for a multiple input protection function and evaluated from the operational side. IIf the AV is determined by the operational. side, exceeding it would indicate that the process instrument loop is potentially operating outside of its design constraints, i.e., a module may be starting to fail - as indicated by a large amount of drift. If the AV is determined by the analysis side, exceeding it would indicate that the process loop is potentially operating outside of the constraints imposed by the analyses assumptions. In summary, when the uncertainty calculations have WCAP- 17044-NP 60 December 2009 Revision 0

sufficient margin to permit it, the difference between the AV and the NTS is large enough to encompass the rack drift, calibration, and M&TE uncertainties.

4.3 The Technical Specifications Provided below is a description and discussion of the three different types of acceptable setpoint licensing approaches. These sections are provided for informational purposes only. Suggestions for inclusion in the Teclmical Specifications are located in Section 4.4.

EU Nominal Trip Setpoint Only In the early "Vendor" or "Custom" Technical Specifications, the RTS and the ESFAS setpoints contained a single value for each function (the NTS). This value was, for the most part, based on engineering judgment accounting for knaown instrument uncertainties. If the NTS was exceeded, the channel was declared inoperable and the plant had to submit an LER. to the NRC. To avoid this situation, the plant used engineering judgment to set the bistable (the field setting) conservative with respect to the Technical Specification value. As discussed in Section 4.2, this practice imposed restrictions on the plant by infringing upon operating margin. This method was not as effective as others for avoiding the reporting requirements because the conservative treatment was voluntary, not used by many plants, and based on engineering judgment which was in conflict with operational desires. As a result of these practices, a significant number of LERs were filed with the NRC. To address this issue, the NRC issued Regulatory Guide 1.1.05 in 1976 and approved the concept of an AV.

EMTwo .Column Specifications Two column Technical Specifications contain an NTS and an AV. While the bistable (field setting) is at or near the NTS, the channel may drift up to the AV during the surveillance interval and still be considered operable. Exceeding this AV, however, was considered a reportable event until 10 CFR 50.73 was issued by the NRC in 1983.

The two column format was intended to reduce the number of LERs by giving the plant a way to accommodate some process rack drift between surveillances. The early versions of the AV included RI) but, unfortunately, only RD, no allowances were made for calibration error. While this was of some benefit to the plants, there were still problems. As explained in NUREG-0452, Rev. 4, this methodology still resulted in the plant setting the bistable conservative with respect to the Technical Specification setpoint by an amount equal to the calibration uncertainty. The potential for an inadvertent LER still remained, but the probability of such an event had been reduced.

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It took the 1981 NRC review of the V. C. Summer setpoint study to extend the AV into a less restrictive form. The current Westinghouse AV is derived from the equations defined in Section 4.2 and provides the plant with increased operational flexibility, the conservatism associated with a 95 % probability calculation, and NRC acceptance.

Unlike earlier versions of the Two Column Specifications, the current version provides the plant more operational flexibility by setting the bistable equal to the NTS. When using the current two column methodology, determining conformance with the Technical Specifications is a straight forward process. For each analog or digital Channel Operational Test (Channel Functional Test), the trip setpoint is determined by measuring the magnitude of the signal, injected at the input to the process racks, whlch provides actuation of the bistable at the output of the process racks. Three criteria for these tests are applicable:

1) If the "as found" trip setpoint is less than the calibration tolerance, and thus the AV, the channel may be operable and no further action is required.

2) If the "as found" trip setpoint is greater than the calibration tolerance, but less than the AV, the channel may be operable, but must be recalibrated to within the calibration tolerance.

3) If the "as found" trip setpoint is greater than the AV, the channel is declared inoperable and appropriate action shall be taken. The channel is not considered operable until the "as left" trip setpoint is within the calibration tolerance.

M The Five Column Specifications The V. C. Summer setpoint study introduced the Westinghouse five colurmn methodology. The five column methodology contains, in addition to the NTS and AV of the two column method, three additional parameters (TA, Z, and S). This five colulmn methodology was designed to reduce the number of LERs by allowing the plant the opportunity to prove that a channel was operable, even though the AV has been exceeded. When the NRC issued 10 CFR 50.73, the filing requirements associated with a LER were significantly changed. An LER must now be filed only in cases where the unit has experienced loss of a function, not just a single channel. This important position change means, among other things, that benefits associated with the Five Column Methodology are no longer necessary to avoid filing an LER.. While Westinghouse does not now recommend the Five Column Methodology, an explanation of the approach is provided here for information. Note that the Technical Specification parameters associated with the Five Colunmn Methodology are listed in Table 4-2 for reference and use in determining chanmel operability on a refueling basis with the sensor errors included.

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Using the Five Column Methodology, determining conformance with the Technical Specifications is a slightly more involved process. For each analog or digital Channel Operational Test (Channel Functional Test), the trip setpoint is determined by measuring the magnitude of the signal, injected at the input to the process racks, which provides actuation at the output of the process racks. Three criteria for these tests are applicable (the first two acceptance criteria are the same as noted previously):

I) If the "as found" trip setpoint is less than the calibration tolerance, and thus the AV, the channel may be operable and no further action is required.

2) If the "as found". trip setpoint is greater than the calibration tolerance, but less than the AV, the channel may be operable, but must be recalibrated to within the calibration tolerance.

3) If the "as found" trip setpoint is greater than the AV, channel operability is determined by satisfying Eq. 4.5. Following the investigation, the channel must be recalibrated to within the calibration tolerance.

E Equations The Five Column Methodology is based on satisfaction of Eq. 4.5. Using the definitions listed below, chanmel operability can be determined, even if the AV has been exceeded, by verifying that the "as found" errors for the channel, not just the process racks, satisfy this equation:

TA> Z+R+S Eq. 4.5 where:

Z {(PMA) 2+(PEA) 2+(S.PE)2 +(STE)2 _.(RTE)2 } E.A BIAS Eq. 4.6 or 1/2 Z=(A) +EA+BIAS Eq. 4.7 and 2 2 2 2 A = (PMA)2 + (PEA) + (SPE) + (STE) + (RTE) Eq. 4.8 R RCA + RMTE + RCSA + RD Eq. 4.9 S= SCA + SMTE + SD Eq. 4.10 or, for multiple input functions.

R=R, +R 2 Eq. 4.11 WCAP- 17044-N P 63 December 2009 Revision 0

where R- = RCAI + RMTEI + RCSA- -RD 1 and R2 = RCA, + RMTE 2 R.CSA 2 + RD2 s- S, + S', Eq. 4.12 S= SCA, + SMTEI + SD, and S2 = SCA 2 + SMTE, + SD 2 WCAP- 17044-NP 64 December 2009 Revision 0

TABLE 4-1 FIVE COLUIMN METHODOLOGY EXAMPLE

[ SAMPLE PARAMETER UNCERTAINTIES (in % span) aXc PMA=

PEA =

SCA =

SMTE SPE =

STE =

SD =

EA =

BIAS =

RCA =

RMTE =

RCSA=

RTE RD=

Instrument Range = 0.00 to-100.00 % SPAN SAL = 100.00 % SPAN NTS 92.00 % SPAN

• SAMPLEICALCULATION RESULTS AV 93.9 % SPAN S = 3.10 A :[ ] Z = 2.96 T2= [ a,c TA = [ I.0c T2=r [ T = 1.9 TA =8.00 CSA=I] MAR- [ ] ac

• • As discussed in Section 3.1, please note that Westinghouse typically reports these numbers to only one decimal place. They are listed in this table with two decimal places only to demonstrate the calculations associated with the methodology.

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WESTINGHOUSE NON-PROPRIETARY CLASS3 PAGE66 TABLE 4-2 REACTOR TRIP SYSTEM / ENGINEERED SAFETY FEATURES ACTUATION SYSTEM CHANNEL / 5 COLUMN METHODOLOGY RESULTS WATTS BAR UNIT 2 PROTECTION CHANNEL TOTAL A S T Z INSTRUMENT TRIP ALLOWABLE ALLOWABLE MAXIMUM ALLOWANCE (1)(9)(13) (2)(9)(13) (3)(9)(13) (4)(9)(13) SPAN SETPOINT VALUE VALUE VALUE (TA)(9) (Norconsenamfve side)(813) (Coiservave side)(13) (7)(13) 1 POWERRANGE,NEUTRON FLUX-HIGH SETPOINT 7.5 20.8 0.0 2.0 4.6 120% RTP 109%RTP 11lA%RTP 106.6%RTP 1 2 POWERRANGE,NEUTRON FLUX - LOWSETPOINT 8.3 20.8 0.0 2.0 4.6 120 %RTP 25 %RTP 27.4% RTP 22.6%RTP 2 3 POWERRANGE,NEUTRON FLUX HIGHPOSITIVERATE 1.6 0.3 0.0 1.1 0.5 120%RTP12SEC 5 %RTP/2SEC 63 %RTPI2SEC 37 %RTP12SEC 3 4 INTERMEDIATE RANGE, NEUTRON FLUX (11) - (111 (11) (11) (11 (11) (11) (11) 4 5 SOURCE RANGE,NEUTRON FLUX (11) - (111 (11) (11) (111 (11) (11) (11) 5 6 OVERTEMPERATURE AT 6,3 23.3 1.1 1.2 7.1 (8) FUNCTION (8) FUNCTION (8) FUNCTION (8) 6

+1.2%AT SPAN -1.2%AT SPAN 7 OVERPOWER AT 4.3 4.1 0.0 1.0 3.3 (61 FUNCTION (8) FUNCTION (8) FUNCTION (8) 1.0%ATSPAN -1.U%ATSPAN 8 PRESSURIZER PRESSURE-LOW,REACTORTRIP 7.5 2.8 2.2 0.7 1.7 880 PSI 1970PSIG 1964.8PSIG 1975.2PSIG 8 9 PRESSURIZER PRESSURE-HIGH 7.5 2.8 2.2 8.7 1.7 . PSI 235PBIG 2302 PSIG 2379.8PSIG 9 10 PRESSURIZER WATER LEVEL - HIGH 0 1.8 2.0 0.7 3.3 100%SPAN 92%SPAN 92.7 %SPAN 91.3%SPAN 10 11 REACTOR COOLANT FLOW-LOW,REACTORTRIP 2.5 1.9 08 0.5 1.4 120%DESIGN FLOW 90%FLOW 89. % FLOW 90.6 % FLOW 11 12 STEAM GENERATOR WATER LEVEL -LOW-LOW 17.0 5.1 2.2 0.7 5.0 100%SPAN 17%SPAN 16.4 %SPAN 17.7%SPAN 12 (OUTSIDE CONTAINMENT) 13 STEAM GENERATOR WATER LEVEL -LOW-LOW 17.0 5.1 2.2 8. 13.2 100%SPAN 17% SPAN 16.4 %SPAN 17.7% SPAN 13 (INSIDECONTAINMENT) 14 UNDERVOLTAGE - RCP (t11 (11) (11) 1111 1111 111 (11) (11) (11) (11) 14 15 UNDERFREQUENCY -RCP (I1) (11) (11) (11) 115 (111 (111 (1 111) 11 )1 16 CONTAINMENT PRESSURE - HIGH 4.1 1.5 2.2 0.5 2.4 17 PSI 1.5 PSIG 1.6PRIG 1.4PRIG 16 17 CONTAINMENT PRESSURE - HIGH-HIGH 4.1 1.5 2.2 0.5 2.4 17 PSI 2.8 PBIG 2S PSIG 2.7 PSIG 17 18 PRESSURIZER PRESSURELOW.SI. 21.2 2.8 2.2 0.7 11.4 800 PSI 1870PSIG 1864.8PBIG 1875.2PSIG 18 19 STEAMUNE PRESSURE -LOW 18.2 1.3 2.2 0.1 6.3 1300PSI 675PSIG 688.6PSIG 683.5POIG 19 20 STEAM GENERATOR WATER LEVEL -HIGH4-IGH 17.0 4.6 2.2 0.1 13.5 100% SPAW 82.4 %SPAN 83.1%SPAN 81.8 % SPAN 20 21 NEGATIVE STEAMUNE PRESSURERATE-HIGH I. 0.1 0.0 0.7 0.3 1300PSI 100 PSI 108.5PSI 91.5 PSI. 21 22 VESSELA*T EQUIVALENT TOPOWER 6.0 4.1 0.0 1.7 2.7 150%RTP RCS LoopAT VariableInput %RTP

_<52.6 -47.4%RTP 22

<50% ofRTP 23 RWSTLEVEL - LOW 8.9 1. 2.2 0.7 1.9 1 %SPA 34.6 %SPAN 34.0 %SPA 35.3%SPAN 23 24 CONTAINMENT SUMPLEVEL 15.6 8. 1.8 0.7 11.9 1..8%0PAR 16.1% SPAR 1.5. %SPA 16.8%SPA2 (111CALCULATIONS PERFORMED BYTV, NOTES:

(1) A=[(PMA) (PEA)'+(SPEI 4'lU (STE)+ (RTE)]

(7) THISCOLUMN BISTABLE PROVIDES ASSUMING THEMAXIMUM A ANDTHELARGEST VALUE FORA VALUE FORS. (121NOTUSED.

8 IPIA S P+ PEl SATISFYING THEEQUATION TAŽ7*S-RIMPUES SOMEMAXIMUM (13) CALCULATION PERFORMED PERTVAINSTRUCTIONS, (31T [+SA+RG0 A+GMTE] VALUEFORR. I.E., THIS COLUMN.

or T,=[(RD,+RCARCA,+CTEORMTE,)T+(RADA+RCA+RCSA2+RMTE1 WITHOUT DETERMINATION THATTHEVALUE OF S T4I IRA] RCA RA T R CCASI ISLESSTHANASSUMED. ABISTABLEBETPOINT IN (5)

TAIIG% 1 ER- BIA EXCESS OF THEALLOWABLE VALUE ANDTHIS T

PRESS 8- PSI COLUMN WOULD BECONSIDERED REPORTABLE.

PET - 150%RTP (8) ASNOTEDINTABLE3.3.1-1OFTHETECHNICAL SPECIFICATIONS.

AT- 160%R,1 (9) ALLVALUES INPERCENT SPANEXCEPT 'A"WHICH ISI%SPANI'.

(10) NOT.USED (6) TAVG -100°F, AT- 150%RTP

4.4 Westinghouse Recommendations As noted throughout this document, the Westinghouse Reactor Protection System Setpoint Methodology has evolved over a period of years. This methodology provides a well defined basis for the RTS and ESFAS setpoints contained in the Technical Specifications. In implementing the RTS and ESFAS setpoints defined in the Technical Specifications, Westinghouse recommends the following:

1. The assumptions made in determining the RTS and ESFAS setpoints identified in this document and supporting references should be validated and implemented.

2. The Technical Specification format should adopt the two column approach with a NTS and an AX' (Non-conservative).

3. Changes in hardware, plant procedures, safety analysis, etc., should be evaluated under the plant change control and IOCFR50.59 process to determine if there is an impact on the assumptions and results of this Reactor Protection System Setpoint Study.

4. Recommendation #3 of Westinghouse Technical Bulletin ESBU-TB-97-01, May 1, 1997 is the preferred method for digital process instrumentation operability determination.

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