ML18018B808

Nonproprietary Ex-Core Axial Power Monitor

ML18018B808
Person / Time
Site:	Harris
Issue date:	09/30/1984
From:	Connors G, Grobmyer L, Tuley C WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML18018B806	List: ML18018B805 ML18018B807 ML18018B808
References
WCAP-10666, WCAPP-10666, NUDOCS 8411120374
Download: ML18018B808 (55)

Text

Westinghouse Proprietary Class 3

WCAP-10666 8411120374 840918 PDR ADOCK 05000400 A

PDR EXCORE AXIAL POWER MONITOR by:

G.

R.

Connors L.

R. Grobmyer C.

R. Tuley APPROVED:

APPROVED:

Septemb r, 1984 F.

L.

angfor

, Jr.,

nager Nuclear Operations D.

N. Katz, M

ager Nuclear Control APPROV D:

C~~

E.

Rahe, Manager ear Safety Department 5303D:4 WESTINGHOUSE ELECTRIC CORPORATION Nuclear Energy Systems P.O.

Box 355 Pittsburgh, Pennsylvania 15230 COPYRIGHT WESTINGHOUSE ELECTRIC, 1984 ALL RIGHTS RESERVED

[1,;

I t

TABLE OF CONTENTS SECTION TITLE List of Figures PAGE 1.0 2.0 2.1 2.2 2.3 2.4 2.5 3.0 3.1 3.2 3.3 4.0 4.1 4.2 4.3 4.4 4.5 4;6 5.0 Introduction

System Description

System Function System Overview Data Entry Calculational Algorithms Calibration Matricies, Definitions and Determinations Data Acquisition and System Calibration Data Types for Calibration Gal ibrati on Requirements.

Plant Operations with ECAPM System Accuracy Flux Map Uncertainties P(z) Uncertainties ECAPM Instrumentation Uncertainties Uncertainty Combination ECAPM Data Comparison ECAPM Technical Specification Modifications Conclusions References 17 17 18 19 22 22 22 24 26 26 27 37 38'ppendix A

Proposed Modifications for Technical Specifications AO

f~

LIST OF'FIGURES FIGURE TITLE PAGE 2-1 2-2 2-3 2-4 3-1 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 ECAPM - Front View ECAPM Block Diagram Microprocessor Unit Block Diagram Calibration Menu Item 3 Typical ECAPM Calibration Comparision of 57 vs.

24 Axial Points ECAPM vs..INCORE - Flat Power Distribution ECAPM vs.

INCORE - Positive AFD Distribution ECAPM vs.

INCORE

-. Negative AFD Distribution ECAPM vs.

INCORE -

D Bank at 193 Steps Withdrawn ECAPM vs.

INCORE - D.Bank at 170 Steps Withdrawn ECAPM vs.

INCORE -

D Bank at 174 Steps Withdrawn ECAPM vs.

INCORE - Burnup Effects 13 14 15 16 21 29 30 31 32.

33 34 35 36

WESTINGHOUSE PROPRIETARY CLASS 3

1. 0 INTRODUCTION The intent of this report is to address the discrepancy in the Shearon Harris FSAR between the power distribution peaking factor, Fq(z), described in section 4.3, Nuclear Design, and that used in section 15.6, LOCA Analysis.

This issue is documented in the Shearon Harris Safety Evaluation Report, Section 1.9, License Condition ¹7, "Restrictions Above 90% Power".

In order to assure operation with Fq(z) remaining below the LOCA limit, Shearon Harris will employ an active surveillance technique based on a concept first described in WCAP-9105 "Axial Power Distribution Monitoring Using Four-Section Ex-Core Detectors".

WCAP-9105 has been previously n

1 1

submitted for information to the NRC; however, it lacks specific system level information such as a hardware description, calibration procedures, and unce'rtainty analyses.

This document is intended to supplement WCAP-9105 in 1

these areas.

Chapter 2 of this report describes the electronic hardware.and operational functions of the Ex-Core Axial Power Monitor.

Chapter 3 describes the method of calibration for the system that ensures that the calculated power distribution is within the accuracy limits's calculated in Chapter 4.

Chapter 5 presents conclusions about the adequacy of the excore approach to axial power monitoring.

5303D'.4

WESTINGHOUSE PROPRIETARY CLASS 3 2.0 SYSTEM DESCRIPTION This chapter summarizes the function of the system and describes the hardware comprising the system.

2.1 SYSTEM FUNCTION The Ex-Core Axial Power Monitor (ECAPM),

shown on Figure 2rl is a surveil-lance system that calculates the core average axial power distribution on a

continuous basis, provides a visual display of the calculated axial power distribution, and activates an alarm should the calculated axial power distribution exceed a predetermined setpoint.

The ECAPM consists of an multi-section excore power range neutron detector that is located within containment (inside a spare detector well) and an

electronics cabinet that is located in the control room.

Fast neutrons that-enter the excore neutron detector are first passed through the window of a moderator/absorber assembly and thermalized before they reach the ionization chamber, where electric currents that are proportional to the magnitude of the the thermalized neutron flux incident on the four sensitive lengths of the detector are generated.

The ECAPM system uses the electric currents from the multi-section ionization

'hamber

assembly, a delta-t based reactor power level signal from the process instrumentation, and a control rod bank D demand position signal from the process instrumentation to calculate the core power levels at a number of discrete points along the height of the core.

Each of the calculated power values is compared to a peak power (KW/FT limit) setpoint for that particular core elevation within the ECAPM system, and if the calculated power distribu-tion equals or exceeds its setpoint value, a peak power (KW/FT) alarm is actuated.

2.2 SYSTEM OVERVIEW Figure 2"2 is a block diagram representation of the ECAPM and its various interfaces.

5303D:4

WESTINGHOUSE PROPRIETARY CLASS 3 The ECAPM electronics cabinet, located in the control

room, houses, the following three major functional subsystems and the subassemblies that comprise each subsystem.

- PLANT INTERFACE UNITS

" Input Signal Conditioning Circuitry

• Digital.Contact Output Card

- OPERATOR INTERFACE UNITS

" Keyboard

" Keyswitch

" Alarm Reset Switch

" CRT

• Status/Printer Panel

- MICROPROCESSOR UNITS

" Peripheral Interface Cards

• Remote Data Acquisition and Analysis Processor (RDAA)

" Man"Machine Interface Processor (MMI).

" Deadman Card

" Non-Volatile Memory

" Analog/Digital Conversion Card 2.2. 1 Plant Interface Units The four current signals from the excore neutron.detector are converted to 0-10 VDC analog signals, filtered, and isolated by the input signal condi-tioning circuitry.

This circuitry also filters and isolates the auctioneered high delta-t and control rod bank D demand position signals from the process instrumentation.

These six signals are then fed to the microprocessor unit for calculation of the axial power distribution.

5303D:4

WESTINGHOUSE PROPRIETARY CLASS 3 The digital contact output card accepts low level voltage input signals from the deadman card of the microprocessor unit and actuates appropriate output contacts that are capable of controlling the higher voltage and currents required to activate the remote alarms located on the Control Room Panel.

2.2.2 0 erator Interface Units The operator interface units as a group provide the operator means to interact with the ECAPM.

Mounted on the turret panel on the front of the ECAPM cabinet are three operator interface units.

The Keyswitch allows the operator to select any one of thr ee modes of system operation (Operate, Calibrate, or Test).

In the Operate mode the system is monitoring signal inputs and the system is considered to be on-line. If the operator selects the Calibrate. mode via the Keyswitch, he can calibrate the system by changing data stored within the system.

This mode of operation is described in greater detail in Section 2.3.

In the Test mode, the operator can conduct vari'ous diagnostic tests on the system by following pre-programmed instructions stored within the system.

If the Keyswitch should fail, the system automatically enters the Test mode of operation to allow diagnostic testing to continue and to alert control room personnel that a system malfunction has occurred.

The Keyboard is a means provided to the operator to initiate action, respond to prompting by the

system, or to make data changes in the system.

The Alarm Reset Switch allows the operator to reset the local. and remote KW/FT Limit alarms ther eby acknowledging these alarms.

The CRT screen is located above the turret panel on the front of the ECAPM cabinet.

It provides a means of visually displaying messages,

graphs, instructions, or data to the operator in a clear and highly visible manner.

The status/printer panel is also located on the front of the ECAPM cabinet between the turret panel and the CRT. It contains a printer and status indicators.

Local/remote status indicators and alarms for the ECAPM consist of status lights mounted on the front of the ECAPM cabinet and annunciators mounted on 5303D:4 4

. WESTINGHOUSE PROPRIETARY CLASS 3

the plant control board.

These alarms indicate that the calculated power distribution equals or exceeds the setpoints (KW/FT LIMIT EXCEEDED), that the system is not functional (SYSTEM FAILURE) due to loss of AC power to the

system, detection of a system diagnostic error, or failure of one or both processors, and that the system is not monitoring axial flux (SYSTEM OFF-LINE) and is in the Test or Calibrate mode of operation.

The printer provides a means of permanently recording hard copies of data specifically requested by the operator or all pertinent data should a power level (KW/FT) alarm be actuated.

2.2.3 Micro rocessor Units Figure 2-3 is a block diagram representation of the microprocessor unit.

This unit consists of two single board computer cards (microprocessor s) that provide the control (MMI processor) and processing capabilities (RDAA processor) of the. system, one non-volatile memory card that stores calibration data, constants, and setpoints should system power be lost, two peripheral interface cards to interface the keyboard and CRT tb the MMI processor via the Multibus, a deadman card that monitors the state of the two single board computer cards and an analog/digital converter'card that interfaces the input signals to the RDAA processor via the Multibus.

Since the ECAPM is a microprocessor-based system, it derives most of its capabilities from its software.

The software not only performs many system functions, but it also controls the order and frequency of execution of these functions.

The MMI Processor, which provides the display and alarm functions, is set up for a ten second loop time.

The RDAA Processor calculates the axial power distribution once per second (one second loop time) to ensure fresh data for the MMI Processor.

2.3.

DATA ENTRY To enter calibration data into the ECAPM the keyswitch must be turned to the position labeled "Calibrate".

When the Calibrate mode is selected, the system responds by displaying the current time of day as determined by the clock that 5303D:4

WESTINGHOUSE PROPRIETARY resides on the non-volatile memory card.

Since this card contains batteries as a back-up power source, the clock continues to keep time even when external AC power to the system is interrupted. If the reported time is incorrect, the operator is able to enter the correct time (24-hour format) via the Keyboard.

The current calendar date follows the time of day display and is also main-tained on the non-volatile memory card.

As with the time, the operator can adjust the calendar date via the keyboard.

After the clock and calendar have been checked and corrected if necessary, a

menu of data structut es that the operator may review and/or modify is dis-played on the CRT screen.

All of, these data are stored in non-volatile memory.

These data consist of calibration constants used in the generation of the axial power profile, and setpoints used by the system software.

The operator selects an item from the calibration menu by entering its corresponding menu

'umber via the Keyboard.

The calibration menu appears on the CRT screen as follows:

CALIBRATION MENU 0=> EXIT CALIBRATE MODE 1=> RADIAL POWER PEAKING FACTOR MATRIX 2=> DETECTOR GAINS VECTOR 3=> CALIBRATION MATRIX 4=>

ROD SHADOW FACTORS MATRIX 5=> KW/FT ALARM SETPOINTS 6=> DATA POINT ELEVATIONS SYSTEMS CONSTANTS 7=>

CORE AVERAGE KW/FT 8=>

C 8( 0 BANKS OVERLAP 9=>

C BANK OFFSET 10=> DISPLAY-ON POWER LEVEL ll=> ALARM"ENABLE POWER LEVEL ENTER THE NUMBER OF THE MENU ITEM TO BE ALTERED.

53030:4

WESTINGHOUSE PROPRIETARY CLASS 3 The system responds to the selection of a menu item by displaying on the CRT the data currently stored as the contents of that menu item..figure 2-4 depicts a sample calibration matrix (menu item 3) as it appears on the CRT screen.

The operator can then review and/or modify any or all of the data within the menu item on display: Operator interaction is via the. Keyboard.

2. 4 CALCULATIONALALGORITHMS The following sections define the algorithms used to generate the power distribution profile for the ECAPM.

The ECAPM first calculates the core average axial power shape, then adjusts it for the radial peaking factor, F

(z), to generate the limiting peaking.

xy factor F (z),

and finally multiplies this by the core average KW/FT to determine the maximum KW/FT(z) to compare to the limiting values

~

2.4.1.1 Core Average Axial Power,

Shape, P(z)

The core average axial power shape is not determined until the multi-section excore detector responses are compensated for the radial power redistribution caused by control bank insertion and fuel depletion.

These corrections are contained in matrices

[N] and [G], control bank insertion and fuel depletion compensations respectively, which are included in the calibration data.

The core average axial power shape is generated by the following equation:

where:

+ape 53030:4

WESTINGHOUSE PROPRIETARY CLASS 3 The P(z) values are then normalized such that the average value is 1.000.

The [G] matrix consists of [

] +a,c The [N] matrix consists of [

]

~ +a,c

+a,c where:

H is Con'trol Bank O position in steps withdrawn, INT is integer conversion by truncation, and OOFFSET is distance between rod bottom and bottom of fuel stack.

Thus, control bank insertion effects on the radial power distribution and the associated excore detector response are compensated for.

2.4. 1.2 Limiting Axial Power Shape, KW/FT(z)

The F (z),the normalized limiting axial power shape, is calculated for each axial elevation z as follows:

where:

Fx (z) is in the calibration data and is labeled as matrix [R].

xy The [R] matrix defines the axially dependent F

for [

xy

].

The current control rod bank position.(input

+a,c signal) is used to determine which F

set to use at each axial position,

~ xy thus the effects of control bank insertion on the radial peaking factors are compensated for.

53030:4

WESTINGHOOSE PROPRIETARY CLASS 8

KW/FT(z), the limiting axial power shape, is determined by multiplying F (z) q by the core average KW/FT being generated at the current power level as follows':

KW/FT(z) = F (z) x C x P

(2.3) where:

C is the full power core average KW/FT entered in the calibration

data, and P is the fractional power level (input value from auctioneered high aT).

2. 5 CALIBRATION MATRICES, DEFINITIONS AND DETERMINATIONS The following sections define the calibration matrices and how they are determined.

These matrices are generated by a calibration code external to the ECAPM.

2,5. 1 Primar Correlation Matrix M

The [M] matrix defines the correlation between the multi-section excore detector response and the core average power shape, P(z).

This is for The [M] matrix is determined by correlating the multi-section excore detector responses to the core average axial power distributions by one of two means.

The first method involves functionally defining the power shape:by a Fourier Series.

This method was well described in WCAP-9105 and it wi 11 not be I

repeated in this document.

The second method involves [

j+a,c 5303D:4

WESTINGHOUSE PROPRIETARY CLASS 3

+a,c

'I The two methods used to determine the

[M] matrix are comparable in the results.

Each method has its advantages and disadvantages, and because of the ease of use, the [

] 'ethod was used in the,error

+a,c evaluation.

2.5.2 Fuel Oe letion Com ensation Matrix G

The [G] matrix is determined by finding the "gain values" to be applied to the detector response to reproduce the known power shape.

The problem is that the determined in the following way.

]. 'he "gain values" are

+a,c From this a set of gains are generated which are [

]. 'ince the purpose of the [G] matrix is to [

+a,c

] a,c 53030:4 10

WESTINGHOUSE PROPRIETARY CLASS 3

'.5.3 Control Bank Insertion Com ensation Matrix N

The [Nj matrix is determined by calculating a set of "gain values" at var'ious control bank insertions,

[

) +a,c The level of fit is selected based on the number of samples.

[

j +a,c 2.5.4 Limitin KW/FT z Matrix T

The [Tj matrix is calculated from the limiting F

, the core average KW/FT at full power conditions, and the K(z) limit curve from the Technical Specifica-tions In the 'calibration code, the K(z) curve is defined by entering four 3

sets of x-y data defining the three segment curve.

The F

value is reduced q

by the uncertainty calculated in Chapter 4 in the calibration code.

The core average KW/FT is used to convert the normalized limit curve to the absolute limit curve.

The equation used to generate the limit matrix is as follows:

[T ] =

/ Fu) x C'x K(z) where:

F

= 1:0 + ZT, u

ZT is the uncertainty described in Chapter 4,

and the other parameters have been previously described, 5303D:4

WESTINGHOUSE PROPRIETARY CLASS 3

The calibration code will collapse the measured F

's to 24 points from the xy nominal 61 points calculated by INCORE The F

's are then [

xy j a,c The method of reducing the number of data points from the nominal 61 points used by INCORE to the 24 points used by ECAPM is by [

2

]. 'ne extra step is used

+a,c in the P(z) calculation and that is a normalization of the input P(z) after the collapse.

5303D:4 12

WESTINGHOUSE PROPRIETARY 10329.3 I

Vi)

D I

Lff~

d gssaegj1 CCA+rdi d

Figure 2-1. ECAPM - Front View

n COC tO mO Q

07 On O

3 4-SECTION EXCORE DETECTOR AUCTIONEERED Hl DELTAT CONTROL BANKD POSITION HIGH VOLTAGE SUPPLY INPUT SIGNAL CONDITIONING EXCORE AXIALPOWER MONITOR CABINET MICROCOMPUTER SUBSYSTEM CRT KEYBOARD KEYSWITCH PRINTER CONTACT OUTPUT CONTROL ROOM ANNUNCIATORS HIGH KW/FT SYSTEM OFFLINE SYSTEM FAILURE M

z QX0CM m

0

-I O

0) o ClM cp

WESTINGHOUSE PROPRIETARY CLASS 3 10329 2 RDAA PROCESSOR PERIPHERAL INTERFACE CRT KEYBOARD INPUT SIGNAL CONDITIONING (SIX SIGNALS)

A/D CONVERTER CMOS RAN M

U L

T I

B U

S PERIPHERAL INTERFACE DEADMAN KEYSWITCH

,STATUS LIGHTS CONTACT.

OUTPUT MMI PROCESSOR PRINTER Figure 2-3. Microprocessor Unit Block Diagram 15

WESTINGHOUSE PROPRIETARY CLASS 3 CALIBRATION MATRIX C

0 R

E E

L E

V A

T I

0 N

S Figure 2-4:

CALIBRATION MENU ITEM 3 - SAMPLE CALIBRATION MATRIX 5303D:4 16

WESTINGHOUSE PROPRIETARY CLASS 3

3.0 DATA AC UISITION AND SYSTEM CALIBRATION'he purpose of this chapter is to establish in detail the requirements and methods for generating and updating the calibration coefficients for the ECAPM

.to ensure an effective axial'ower distribution monitoring program.

3. 1

- DATA TYPES FOR CALIBRATION There are three types of data used in generating the calibration coefficients for the ECAPM.

From earlier work on multi-section excore detectors, these types were labeled Type-A, Type-B, and Type-C.

The contents and function. of each data type are described below.

Type-A data consists of the information required to correlate the excore detector's responses to the axial power distributions, specifically, the [M]

matrix determination.

These data come from the flux map data, quarter core (gCFM) and full core (FCFM), obtained during an incore-excore calibration where [

]

The data consists of the core average axial power shape from the flux map analysis results from the INCORE code or equivalent and the corresponding 2

+a,c excore responses for a minimum of [

a,c Type-B data is identical in form to the Type-A data with the exception that this data is used to generate the fuel depletion compensation matrix, [G], or the control bank inSertion compensation matrix, [N].

The [G] matrix is determined from the first Type-B data set which should be [

]. 'hi's matrix adjusts the calibration to improve the ECAPM accuracy.

+a,c 5303D:4 17

WESTINGHOUSE PROPRIETARY CLASS 3 Conversely, to determine the [N] matrix, [

]. 'herefore, the [N] matrix is determined from data taken at equivalent power and burnup conditions as the Type-A data and the

[G] matrix is determined from data at different power and/or burnup conditions as the Type-A data.

Type-C data is primarily the F

information (matrix [R]), the data required to generate the limits matrix, [T], and the calculation constants and options.

The only data that is periodically updated are the F

data xy

3. 2 CALIBRATION REQUIREMENTS To maintain the ECAPM calibration in an optimum condition, periodic calibra-tions and calibration tuneups must be performed.

These are designed to be consistent with the current Technical Specification requirements for the 3

excore power range detector calibration and the peaking factor surveillance.

Specifically, the ECAPM must be calibrated before it is required for use following a refueling outage and recalibrated quarterly thereafter, Also, the calibration must be adjusted (calibration tuneup) on a monthly basis, consistent with the peaking factor surveillance requirements.

3.2.1 Calibration Oata and Testin Re uirements To completely calibrate or recalibrate the ECAPM, data must be acquired to generate all types of data sets.

The necessary information is obtained during an Incore-Excore calibration with a minimum span in Axial Offset of

+a,c

[

] 'ver the Type-A data maps.

These measurements are typically made between 70:o and 805 power for the expressed purpose of calibrating the installed power range excore detectors.

A typical calibration is shown on Figure 3-1 and in Reference 4.

Refer ring to Figure 3-1, the [

] 'rovides the F

data for the Type-C data, it is the 53030:4 18

WESTINGHOUSE PROPRIETARY CLASS 3

] 'or the [N] matrix determination

data, and it.is also included in the Type-A data.

All other flux maps, gCFM's or FCFM's, are noted as either Type-A data or Type-B data by the subscripts on Figure 3-1.

.[

] +a,c 3.2.2 Calibration Tuneu Data and Testin Re uirements The calibration tuneup is designed for two purposes.

First, it is used to adjust the calibration performed at reduced power to full power conditions.

Second, it is used to adjust the calibration for changes in the multi-section excore detector to core coupling caused by fuel depletion.

Therefore, the tuneup is performed immediately following a quarterly calibration and periodi-cally thereafter.

The tuneup data consists of [

By using the current [

.], 'he

[G] matrix and the F

's can be xy determined and updated.

3.3 PLANT OPERATIONS WITH ECAPM Below the setpoint power level, the ECAPM will perform its function, but it is not required for power distribution control or monitoring.

At these reduced'ower

levels, proper power distributions are assured by the restrictions on the plant operating parameters such as Axial Flux Difference and the control bank insertion limits.

When the reactor power level exceeds the ECAPM power setpoint, the system must be operational.

If it is not operational and calibrated then the reactor power must be reduced to below the power setpoint.

When the measured KW/FT exceeds the alarm setpoint, a high limit alarm will be indicated and the main control board annunciator will sound.

The operator must then take action based on the current operating conditions of the plant.

In other words, power 'reduction must be made.

The power reduction required is indicated by how much the KW/FT 'exceeds the limit curve.

The return to power 53030:4 19

WESTINGHOUSE PROPRIETARY CIASS 3

may be accomplished by controlling the axial power shape with control bank posi'tion adjustment to reduce the axial peaking in the offending portion of the core.

The decision making process is power independent, therefore the appropriate operator action can proceed.

Alternatively, adjustments to the control bank position while above the ECAPM power setpoint can be done to prevent a

KW/FT alarm.

The ECAPH provides the operator the margin to limit and the axial location of the minimum margin, thus providing the necessary data for educated power distribution adjustments.

5303D'4 20

14 12 SAMPLE TECH. SPEC. LIMIT 100 4

'g 2

<I O

0 00Z

-6

-10

-12

-14 0

10 12 14 TIME (HOURS) 16 18 20 22 24 Figure 3-1 Typical ECAPM Calibration

C

WESTINGHOUSE PROPRIETARY CLASS 3

4.0 SYSTEM ACCURACY In this Chapter the uncertainties of the ECAPM are discussed and combined to determine a 'system accuracy.

There are three basic areas of uncertainties to consider; I) those uncertainties associated with the use of a flux map in determining P(z) and F~, 2) P(z) uncertainties associated with the use of the correlation and algorithms, and 3) instrumentation uncertainties.

Also provided in this chapter are several figures comparing the INCORE code results to the algorithm results based on actual plant flux map and excore detector data, and a proposed set of Technical Specifications to address use of the system.

4.1 FLUX MAP UNCERTAINTIES The ECAPM'uses a series of full and quarter core flux maps for the determination of calibration constants thus, it is appropriate to include applicable flux map uncertainties.

It was determined that the standard Westinghouse uncertainties for a flux map are indeed applicable.

These uncertainties are:

+ 5X for F~

, to account for'engineering.

and manufacturing E

tolerances for F~

, to account for measurement uncertainties, and MU 7 'or F, to conservatively account for the effects

+a,c RB of rod bow.

These uncertainties have been discussed in detail in other Westinghouse topical reports 'nd wi.ll not be covered here.

5, 6

4.2 P(z)

UNCERTAINTIES In addition to the above, ECAPM uses 24 axial points instead of 57, which was the number of axial points used in the test data.

Collapsing the number of points introduces an error [

]

Forty-five full and quarter core flux maps were used to calculate the peak value of Fz 53030:4 22

WESTINGHOUSE PROPRIETARY CLASS 3 using 57 and 24 axial points.

A comparison was then made between the two sets of data to determine the difference, i.e.,

57 F

24 zi zi i

24 zi A plot of 6.

assuming a [

resulting 2o used [

value was [

]

A conservative value of [

+a,c 57

]+a,c

] 'as indicated that the distribution was conservatively bounded by

]

Figure 4-1 provides a comparison

+a,c of the normalized axial power shape when using 57 and 24 axial points.

As can be seen from the figure, the use of 24 axial points is reasonable (and conservative whe'n corrected by the above noted amount).

ECAPH presents a picture of the core in terms of core average P(z) and is based on the calibration of the excore detector set to a series of incore flux maps.

There is an uncertainty introduced as a result of this calibration.

The magni-tude of the uncertainty was determined by examining the pointwise standard deviations for 20 cases of Type-A data (480 points) using [

]

This resulted in a frequency distribution that is

+a,c quite peaked,

[

]

Based on an evaluation of the data, it was

+a,c conservatively estimated that the uncertainty value of Z

= [

]

1 more than adequately represented a 2a value (evaluation of the data indicates

[

] 'f the population is enveloped by the uncertainty).

+a,c Another uncertainty associated with P('z) is the error introduced by control bank insertion.

An evaluation was performed using the point wise standard deviations for 3 cases of Type-B data (a total of 69 points).

The degree of 53030:4 23

WESTINGHOUSE PROPRIETARY CLASS 3

bank insertion varied with D bank inserted as deep as 58 steps (170 steps withdrawn).

The frequency distribution for the data is center peaked but with some outliers.

It was determined that a [

]

Using this assumption'results in a 2o value of Z2 = [

']

This uncertainty encompassed

. +a,c

[

'] 'f the data.

Further evaluation of the F

data noted that [

z

]

It is therefore believed that the uncertainty for bank insertion is quite conservative.

The final uncertainty affecting P(z) is burnup.

As the cycle progresses the ECAPM must be recalibrated quarterly and adjusted monthly.

There exists only limited data with regards to burnup effects on the accuracy of the system.

Westinghouse has only one set of data, two flux maps taken - 1100 MWD/MTU apart where multi-section excore and moveable detector data are both available.

With the limited data, it was difficult to isolate the effects of just burnup, thus clouding a definitive value determination.

The results of an evaluation of the data were inconclusive. 't appears that the system ['

'see Figure 4-8).

Westinghouse proposes that more extensive data be accumulated early in Cycle 1 to determine if an uncertainty is needed.

It is suggested that Type-B data (gCFM) be. gathered on a weekly basis in conjunc-tion with ECAPM response.

If the system continues [

]

If the system demonstrates a [

+a,c

]+a,c 4.3 ECAPM INSTRUMENTATION UNCERTAINTIES As noted in Chapter 2, ECAPM has three sets of inputs;

1) reactor power (based on 4T), 2) bank position, and 3) excore detector section currents.

Two of the input uncertainties have negligible effects, hT and rod position.

While it is acknowledged that an uncertainty in power would effect the calculated 5303D:4 24

WESTINGHOUSE PROPRIETARY CLASS 3 value for KW/FT, the manner in which the signal for power is generated is conservative.

The hT signal for each of the three loops is compared against the other two and the highest value is used.

This insures that a conservative power signal/value is used for ECAPN calculations, even accounting for unequal distributions of power sharing between loops.

Therefore no uncertainty is included for hT in the uncertainty analysis.

The bank demand position indication system is reasonably accurate

(+ 6 steps) which would have only a small effect on ECAPM accuracy.

Basically, bank position errors would only influence the perceived location of the control rod tips.

This is not a critical parameter with respect to deter-mination of the peak value of KW/FT because the peak value is not located at or near the tips of the rods, but some distance below them.

Based on the bank insertion data comparisons used in Section 4.2, and the results indicated in Figures 4-5, 6 and 7, the peak value calculation would not be impacted.signi-ficantly, i.e., [

]+a,c The uncertainty associated with the excore detector currents is based on the conversion of the current signals to voltage and from an analog signal to a digital signal.

The accuracy of the absolute value of the signal is not important to the system due to the normalization/calibration of the detector outputs/algorithms to the flux map series.

What is important to the operation of the system is the stability and reproducibi lity of the current signal.

An investigation of the electronic components indicated that the stability and reproducibility of the current to voltage conversion is [

]

The accuracy of the A/D conversion is [

]

The microprocessor has negligible uncertainties.

Therefore, the total uncertainty of the electronic conversion process is [

]

To be conservative, for

+a,c this analysis a value of Z3 = [

] 'as used for each of the four sections of the excore detector.

5303D:4 25

WESTINGHOUSE PROPRIETARY CLASS 3

4. 4 UNCERTAINTY COMBINATION An evaluation of the uncertainties indicated, that from a statistical point of view,'he various components were independent, thus simplifying the calcula-tion.

Based on this determination the total uncertainty for use of the ECAPM is:

j+a, c j+a,c j+a,c As noted in Section 4.2 the uncertainty due to [

+a,c j

At this time this appears reasonable and will be con-firmed early in Cycle 1.

The use of Z is fairly simple, the alarm setpoint (equivalent to the K(z) limit of Figure 3.2.2 of the plant Technical Specifi-cations) is reduced by the amount of Z This assures operator notification of a'ossible peaking factor'violation prior to its occurrence.

'.5 ECAPM OATA COMPARISON To demonstrate the capabilities of the ECAPM as compared to a full or quarter core flux map, several figures were generated.

The first set of figures 4-2, 3,

and 4 were generated as the equivalent of distributions expected and used as part of the normal calibration procedure, i.e.,

a Xenon oscillation.

Figut e 4-2 is representative of a flat to slightly double humped distribution which was present at the start of the calibration run

~

As can be seen, the ECAPM tracks the 57 axial point flux map very well [

]

Figure 4-3 is for a top skewed

+a,c (positive AFD) power distribution.=

Figure 4-4 is for a bottom skewed (nega-tive AFD) power distribution.

Again in both cases the ECAPM conservatively determines the peak values.

All figures provided are traces of the best estimate calculated values, i.e no uncertainties were included in the flux map results and the ECAPM trace is what would be produced by the device (the

~

53030."4 26

WESTINGHOUSE PROPRIETARY CLASS 3

ECAPM uncertainties being factored into the limit).

For*the purposes of comparison, the K(z) limit for the plant from which this data was taken is provided at the top of each figure.

Figures 4-5, 6, and 7 were generated as the equivalent of distributions expected and used as part of the control bank insertion calibration.

Figure 4-5 has D bank at 35 steps inserted (193 steps withdrawn, core height - 122 inches).

Figure 4-6 has D bank at 58 steps inserted (170 steps withdrawn, core height - 108 inches).

Figure 4-7 has D bank at 54 steps inserted (174 steps withdrawn, core height - 110 inches).

As can be easily seen in the

figures, ECAPM tracks the flux map results very well [

~+a,c Finally, Figure 4-8 is a comparison of ECAPM to a flux map to demonstrate the effects of burnup.

In this instance the ECAPM constants were adjusted to a.

case at a burnup of 2845 MWD/MTU.

The multi-section detector data taken at the time of a flux map produced at a burnup of 3954 MWD/MTU was used as input to the algorithms.

When compared to the flux map it is fairly obvious that the ECAPM is working with [

3 The amount of

+a,c burnup between the two cases (adjustment and comparison) is greater 'than that allowed in.the proposed Technical Specifications.

Based on the conservatism demonstrated by the ECAPM in this instance, Westinghouse believes that the one week interval between data points to generate and determine the effects of burnup is reasonable and conservative.

4.6 ECAPM TECHNICAL SPECIFICATION MODIFICATIONS In Appendix A, proposed modifications have been made to the applicable p'lant Technical Specifications.

These changes are based on FO

= 2.32 and F~

= 2.1,. the actual values of affected power levels would change as the ratio of F~

to F~

changes.

The proposed modifications or power level changes LOCA ND are noted by a bar in the right margin.

Please note that unlike APDMS, ECAPM uncertainties are factored into the limit, not the calculated value for com-parison to the limit.

This results in several changes in the action to be 5303D:4 27

WESTINGHOUSE PROPRIETARY CLASS 3 taken in the event of an alarm indication, i.e,, the functions performed by APDMS and ECAPM are essentially the same but the manner in which the comparison of data to the limit is made is different, thus requiring somewhat different-action.

This difference is most notable in ACTION a.2 of specification 3:2:2 and ACTION a. of specification 3.2.6 on the proposed modifications.

It is believed that use of ECAPM in conjunction with the proposed specifications at power levels in excess of (F~

)/(F~

) will result in operation consistent LOCA ND with the assumptions of the Nuclear Design and LOCA analyses.

5303D:4 28

+a,c 12 24 36 48 60 72 04 96 1GO 120 132 144 BOTTOM CORE HEIGHT

( IN)

TOP Figure 4-1 Comparison of 57 vs 24 Axial Points Power Profile

2 0

1-5 C)

~1 0

z0.5 0.0 0

12 24 36 48 60 72 84 96 BOTTOM CORE HC IGHT

( lN) 108 120 132 144 TOP Pl C/l ED C/l Cll Kl C)

Z7 Dl

Ã7C I

C/l C/l Figure 4-2 ECAPH vs INCORE - Flat Power Distribution

~2.0 1-6 Pl tA C3 Vl m

C) laJ<1.0 CE zO.S 0

0

~

I I

I 12 24 36 48 60 72 84 S6 108 120 132 144 HOT TOti CORE HEIGHT

( IN )

TOP Figure 4-3 ECAPN vs INCDRE Positive AFD Distribution

I

~

+a,c I

U

@~2-0 I

~1-5 m

C/l C)

Vl Pl

~l

~ 0 CK z0.5 I

C/)

0.0 I

I I

I I

0 12 24 36 48 60 72 84 96 108 120 132 144 BOTTOM CORE HEIGHT

< IH)

TOP Figure 4-4 ECAPH vs INCORE Negative AFD Distribution

+a,c C3 1

5 Clll/l CD Vl Pl C)

~1

~ 0 CL CDz0.5 CD Kl m

KI 0.0 0

I I

I I

I 12 24 36 46 60 72 64 96 106 120 132 144 BOTTOt1 CORE HE IGHT

( IN )

TOP Figure 4-5 fCAPM vs INCORf - 0 Bank at 193 Steps 1lithdrawn

2.6

+a,c m

Vl CD Ul Pl

ÃI CD

ÃI m

12 24 36 48 60 72 84 96 108 120 132 144 BOTTOM CORE HEIGHT

( IH)

TOP Figure 4-6 ECAPH vs INCORE - 0 Bank at 170 Steps

>lithdrawn

I 4

2.0 1.5 CI

<1-0 CL C)z0.5-Pl C/l C) tA m

0.0 0

,12-24 36 48 60 72 84 96 BOTTOM)

CORE HE IGHT

( IN )

108 120 132 144 TOP Figure 4-7 ECAPM vs INCORE -

D Bank at l74 Steps Withdrawn.

2.6 a,c

~1.0 m0.5 P1 CA C)

CD Vl Cll X7 CD m

I Vl 0

0 0

12 24 36 48 60 72 84 96 108 120 132 144 ROTTOt1 CORE HEIGHT

( IH)

TOP Figure 4-8 ECAPH vs INCORC - Burnup Effects

WESTINGHOUSE PROPRIETARY CLASS

5. 0 CONCLUSIONS Based on the figures supplied as part of Chapter 4 it can be easily seen that the ECAPN will conservatively determine the peak axial value of KW/FT for the purpose of notifying the operator of a potential Technical Specification viola-tion.

The system operates real time, providing the operator with a graphic display of the core average axial power distribution and margin to the analysis limit.

This information is sufficient to allow the operator to anticipate and identify potential concerns and to make judgements about the proper action to take.

Based on the information presented in this 'document, Westinghouse believes that plant operation in excess of the turn-on power for ECAPM is acceptable and within the analysis assumptions (both LOCA and FAC) when so indicated by the ECAPM system.

53030:4 37

WESTINGHOUSE PROPRIETARY CLASS 3

REFERENCES 1.. Easter, J.

R., "Axial Power Distr'ibution Monitoring Using Four-Section Ex-Core Detectors",

WCAP-9105 (Proprietary),

WCAP"9106 (Non-Proprietary),

7/77.

2.

Haris, A. J., Jones, K. A., "The INCORE Code",

WCAP-8492 (Propri.etary),

3/75.

3.

"Standard Technical Specifications for Westinghouse Pressurized Water Reactors",

NUREG-0452, Revision 4, Fall 1981.

4.

Kerr, R. A., "Excor e Detector Recalibration Using Quarter Core Flux Maps",

WCAP-8648-A (Non-Proprietary),

2/79.

5, Westinghouse letter NS-EPR-2900, 4/5/84, from.E.

P.

Rahe (W) to Cecil 0.

Thomas (NRC), "Update to WCAP-7308-L, Topical Report, Evaluation of Nuclear Hot Channel Factor Uncertainties".

6.

Grigsby, J.

M., Spier, E. M., Tuley, C. R., "Statistical Evaluation of LOCA Heat Source Uncertainty:,

WCAP-10395 (Proprietary),

WCAP-10396 (Non-Proprietary),

11/83.

5303D:4 38

APPENDIX A PROPOSED MODIFICATIONS FOR TECHNICAL SPECIFICATIONS AO

WESTINGHOUSE PROPRIETARY CLASS 3 3/4.2 POWER DISTRIBUTION LIMITS AXIAL FLUX DIFFERENCE (AFD)

LIMITING CONDITION FOR OPERATION 3.2.1 The indicated AXIAL FLUX DIFFERENCE (AFD) shall be maintained within the following target band (flux difference units) about the tar-get flux difference:

a.

+.5 percent for core average accumulated burnup of less than or equal to 3000 MWD/MTU.

b.

+

3 percent,

-12 percent for core average accumulated burnup of greater than 3000 MWQ/MTU.

APPLICABILITY:

MODE 1 above 50 percent of RATED THERMAL POWER*

ACTION a.

With the indicated AXIAL FLUX DIFFERENCE outside of the above required target band about the target flux difference and with THERMAL POWER'.

Above 81 percent of RATED THERMAL POWER, within 15 minutes:

a)

Either restore the indicated AFD to within the above required target band limits, or b)

Reduce THERMAL POWER 'to less than 81 percent of RATED THERMAL POWER:

2.

Between 50 percent and 81 percent of RATED THERMAL POWER:

a).

POWER OPERATION may continue provided:

1)

The indicated AFD has not been outside of the above required target band for more than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> penalty deviation cunulative during the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and 2)

The indicated AFD is within the limits shown on Figure 3.2-1.

Otherwise, reduce THERMAL POWER to less than 50.percent of RATED THERMAL POWER within 30 minutes and reduce the Po~er Range Neutron Flux-High Trip Setpoints to less than or equal to 55 percent of RATED THERMAL POWER within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

• See pecia Test Exception 3.10.2..

t WESTINGHOUSE PROPRIETARY CLASS'

~ POWER DISTRIBUTION LIMITS ACTIONS:

(Continued) b)

Surveillance testing of the Power Range Neutron Flux Channels may be performed pursuant to Specification'.3.1.1.1 provided the indicated AFD is maintained with-in the limits of Figur e 3.2-1.

A total of 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> operation may be accuoulated with the AFD outside of the above required target band during this testing without penalty deviation.

b.

THERMAL POWER shall not be increased above 81 percent of RATED THERMAL POWER unless the indicated AFD is within the above required target band and ACTION 2.a) 1), 'above has been satisf ied.

C.

THERMAL POWER shall not be increased above 50 percent of RATED THERMAL POWER un'less the indicated AFD has not been outside of the above required target band for more than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> penalty deviation cumulative during the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

SURVEILLANCE REQUIREMENTS 4.2.1.1 The indicated AXIAL FLUX DIFFERENCE shall be determined to be within its limits during POWER OPERATION above 15 percent of RATED THER-MAL POWER by:

a.

Monitoring the indicated AFD for each OPERABLE excore channel:

1.

At least once per 7 days when the AFD Monitor Alarm is

'PERABLE, and 2.

At least once per hour for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after restor-ing the AFD Monitor Alarm to OPERABLE status.

b.

Monitoring and logging the indicated AXIAL FLUX DIFFERENCE for each OPERABLE excore channel at least once per hcur for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and at least once per 30 minutes thereafter, when the AXIAL FLUX DIFFERENCE Monitor Alarm is inoperable.

The logged values of the indicated AXIAL FLUX DIFFERENCE shall be assumed to exist during the interval preceding each logging.

4.2.1.2 The indicated AFD shall be considered outside of its above required target band when at least 2 of 4 or 2 of 3 OPERABLE excore channels are indicating the AFD to be outside the target band.

Penalty A2

WESTINGHOUSE PROPRIETARY CLASS 3

POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS (Continued) deviation outside of the above required target band shall be accumulated on a time basis of:

a.

One minute penalty deviation for each one minute of POWER OPERA-TION outside of the target band at THERMAL POWER levels equal to or above 50 percent of RATED THERMAL POWER, and b.

One-half minute penalty deviation for each one minute of POWER OPERATION outside of the target band at'HERMAL POWER levels between 15 percent and 50 percent of RATED THERMAL POWER.

4.2.1.3 The target flux difference of each OPERABLE excore channel shall be determined by measurement at least one per 92 Effective Full Power Days.

The provisions of Specification 4.0.4 are not applicable.

4.2.1.4 The target flux difference shall be updated at least once per 31 Effective Full Power Days by either determining the target flux dif-ference pur suant to 4.2.1.3 above or by linear interpolation between the most recently measured value and 0 percent at the end of the cycle life..The provisions of Specification 4.0.4 are not applicable.

A3

MESTINGHOUSE'ROPRIETARY CLASS 3 1.0 Og~

ECAPR TURN ON POWER (90%)

UNACCEPTABLE OPERATION

(-9, 81) 0.8 (9, &1)

UNACCEPTABLE OPF RATION 0.7 cc O'-24, 50) l K

O C4 0.6 ACCEPTABLE OPERATION 0.5 0.4 0.3 (24, 50) 0.2 0.1

-30

-20

-10 0

10 20 INDICATED AXIAL FLUX DIFFERENCE (d,l) 30 Figure 3.2.1.

Axial Flux Difference Limits as a Function of Percent Rated Thermal Power A4

WESTINGHOUSE PROPRIETARY CLASS 3 POWER DISTRIBUTION LIMITS HEAT FLUX HOT CHANNEL FACTOR-F (Z)

LIMITING CONDITION FOR, OPERATION 3.2.2 Fq(Z) shall be limited by the following relationships:

PO(Z)

< (Z.IO)

[K(Z)) for P

> 0.5 Fq(Z)

< [4.20]

LK(Z)3 for P

< D.5 where P

THERMAL POWER RATED THERMAL POWER and K(Z) is the function obtained from Figure 3.2-2 for a given core height location.

APPLICABILITY:

MODE 1'CTION:

With Fg(Z) exceeding its limit:

Comply with either of the following actions.

a.

1.

Reduce THERMAL POWER at least 1 percent for each 1 percent Fq(Z) exceeds the limit within 15 minutes and similarly reduce the Power Range Neutron Flux-High Trip Setpoints within the next

.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />; POWER OPERATION may proceed for up to a total of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.;

subsequent POWER OPERATION may pro-ceed provided the Overpower aT Trip Setpoints have been reduced at least 1 percent for each 1 percent FO(Z) exceeds the limit.

The Overpower aT Trip 'Setpoint reduction shall be performed with the reactor in at least HOT STANDBY.

2.

Reduce THERMAL VOWER as necessary to meet the limits of Specification 3.2.2 using the ECAPM.

b.

Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER above the reduced limit required by a, above; THERMAL POWER may then be increased pro-vided FO(Z) is demonstrated through incore mapping to be with-in its limit.

A5

WESTINGHOUSE PROPRIETARY CLASS 3

POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS 4.2.2.1 The provisions of Specification 4.0.4 are not applicable.

4 2

2 2 Fxy shall be evaluated to determine if Fq(Z) is within its.

limit by:

a.

Using the movable incore detectors to obtain a power distribu-tion map at any THERMAL POWER greater than 5 percent of RATED THERMAL POWER.

b; Increasing the measured Fxy component of the power distribu-tion map by 3 percent to account for manufacturing tolerances and further increasing the value by 5 percent to account for measurement uncertainties.

c.

Comparing the Fxy computed (Ffy) obtain in b, above to:

~

1.

The Fy limits for RATED THERMAL POWER (F(y

) for the appropriate measured core planes given in e and f below, and 2.

The relationship:

F[

F(TP [1+0.2(l-P)j.

where,F[y is the limit for fractional THERMAL POWER operation expressed, as a function of F)yTP and P is the fraction of RATED THERMAL POWER at which Fxy was measured.

d.

Remeasuring Fxy according to the following schedule:

1.

When Ffv is greater than the F(y limit for the appr oprlate measur ed core plane but less than the Ff r elationshig, additional power distribution maps sha/1 be taken and Ffy compared to FfyTP and Ffy..

a)

Either within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after exceeding by 20 percent of RATED THERMAL POWER or greater, the THERMAL POWER at which Ffy was last determined, or b)

At least once per 31 EFPO, whichever occurs first.

A6

WESTINGHOUSE PROPRIETARY CLASS 3

POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS 2.

When the Ff is less than or equal to the FCIyP limit for the appropriate measured core plane, additionai power distribution maps shall be taken and p(

com-pared to FIR>tp and F)> at ieast once per 31 EF D.

e.

The Fxy limits for RATED THERMAL POWER within specific core planes shall be:

1.

FEIT>P

< 1.71 for all core planes containing bank "D"

control rods, and 2.

FCRyTP

< 1.55 for all unrodded core planes.

f.

The Fxy limits of e,

above, are not applicable in the follow-ing core planes regions as measured in percent of core height from the bottom of the fuel:

1.

Lower core region from 0 to 15 percent, inclusive.

2.:

Upper core region from 85 to 100 percent, inclusive.

3.

Grid plane regions at 17.8 + 2 percent, 32.1 + 2 percent, 46.4

+ 2 percent, 60.6 +

2 percent and 74e9

+ 2 percent, inclusive.

4.

Core plane regions within + 2 percent of core height

(+ 2.88 inches) about the bank demand position of the bank "D" con-trol rods.

g.

With F(y exceeding Ffy.

1.

The Fp(Z) limit shall be reduced at least 1 percent for each I percent Ffy exceeds Ffy, and 2.

The effects of Fxy on FQ(Z) shall be evaluated to deter-mine if Fq(Z) is within its limits.

4.2.2.3 When FQ(Z) is measured for other than Fxy determinations, an ov'erall measured Fp(Z) shall be obtained from a power distribution map and increased by 3 percent to account for manufacturing tolerances and further increased by 5 percent to account fo'r measurement uncer-tainty.

A7

WESTINGHOUSE PROPRIETARY CLASS 3 1,2 1.0 (6.0, 1.0)

(11.18,.934)

N 0.8 Q

N 0.6 ccOz I

0.4 hC (12,,714) 0,2 0

0 4

6 8

CORE HEIGHT (FT) 10 12 Figure 3.2-2.

K(Z) Normalized F<(Z) as a Function of Core Height

WESTINGHOUSE PROPRIETARY CLASS 3

3.2.6

'Ihe Excore Axial Power Monitor (ECAPM) shall be operable at power levels above 90% of RATED THERMAL KWER.

9l KXjQH,: With the ECAPM determined to be inoperable:

a.

Either.evaluate the impact on the margin between the Best'stimate ECAPM lm/ft value and it's limit and adjust. correspondingly, or b.

Reduce THERMAL KWER to less than or equal to 90$ of RATED THERMAL POWER.

4.2.6.1 The ECAPM shall be verified to be OPERABLE monthly by verification that the Best Estimate ECAPM lm/ft margin to limit is less than or equal to the Best Estimate Full Core Flux Map'Q(z) margin to limit.

4.2.6.2

'Ihe ECAPM calibration shall be adjusted monthly by use of a Full'ore Flux Map to determine input values for the Fuel Depletion Compensation Matrix.

4.2.6.3 The ECAPM shall be calibrated quarterly via use of the Full Core and Quarter Core Flux Maps to determine input values for the Calibration Matrix and the Rod Insertion Compensation Matrix.

The ECAPM may be out of service when inputting and verifying calibration constants, providing THERMAL KWER is maintained in a steady state condition and indicated AK is maintained within z 3$ of the AFD target value.

A9