ML20037A283
| ML20037A283 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 07/02/1979 |
| From: | ARKANSAS POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20037A282 | List: |
| References | |
| NUDOCS 7907020161 | |
| Download: ML20037A283 (45) | |
Text
l ARKANSAS POWER & LIGilT COMPANY ARKANSAS NUCLEAR ONE UNIT 2 DETERMINATION OF PLANT PROTECTION SYSTEM TRIP SETPOINT VALUES 9
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l Page i TABLE OF CONTENTS g
,, 2 Section Title Page No.
Cover Table of Contents i
List of Tables 11 List of Figures lii List of Acronyms and Abbreviations iv
1.0 INTRODUCTION
1.1 Scope 1
1.2 Background
1 2.0 SETPOINT METHODOLOGY 2.1. Basic Description 2
2.2 Analysis Setpoint 3
2.3 Equipment Errors 4-7 2.4 Setpoint Determination 8&9 2.5 Core Protection Calculator Setpoints 9 - 16 2.6 Equipment Calibration 17 - 19 3.0 DETAILED SETPOINT DATA 3.1 1;RC Request 20 3.2 Explanation Of Tables 20 - 24
4.0 REFERENCES
25 T/diLES 26 - 32 FIGUPIS 0
l
LIST OF TABLES s
Table No.
Title Page No.
1 PPS Equipment Setpoints, Allowable Values and Drif: Allowances 26 2
PPS Instrument Sias Components 27 3
PPS Instrument Bias Components, Continued 28 4
PPS Analysis Setpoints and Se: point Margins 29 5
PPS Core Protection Calculator Trip Setpoint Data 30 6
PPS Core Protection Calculator Process Equipment Lias Components 31 7
PPS Core Protection Calculator Process Equiptent Bias Components, Continued, and Total Allowances 32 O
l LIST OF FIGURES Figure No.
Title Page No.
1 Setpoint Calculation Methodology 2
Analysis Sctpoint Initial Determination 3
Plant Protection System Block Diagram 4
Plant Prctection System Time Delay Compen-sation 5
Equipment Setpoint Determination Using Event Specific Data 6
Reactor Protection System Inputs and Trip Functions 7
Core Protection Calculator as Part of the Reactor Protection System 8
Round-off Effects on Equipment Setpoints and Allowable Values
LIST OF ACRONYMS AND Jb3REVIATIONS s
ACRS Advisory Committee on Reactor Safeguards A/D Analog to Di S tal Converter i
ANO-2 Arkansas Nuclear One - Unit 2 AP&L Arkansas Pcwcr 6 Light Company ASP Analysis Setpoint AV Allowable Value CCAS Containment Cooling Actuation Signal CE Combustion Engineering CEA Control Element Assembly CEAC Control Element Assembly Calculator CEDM Control Element Dri';e Mechanism CFR Code of Federal Regulations CIAS Containment Isolation Actuation Signal CSAS Containment Spray Actuation Signal DBE Design Basis Event DNBR Departure From Nucleate Boiling Ratio EFAS Emergency Feedwater Actuation Signal ESF Engineered Safety Features ESFAS Engineered Safety Features Actuation System FSAR Final Safety Analysis Report IEEE Institute of Electrical and Electronics Engineers LCO Limiting Conditions for Operation LER Licensee Event Report LPD Local Power Density MSIS Main Steam Isolation Actuation Signal N.A.
Not Applicable NRC Nuclear Regulatory Commission OL Operating License PPS Plant Protection System RCP Reactor Coolant Pump R.G.
Regulatory Guide RPS Reactor Protection System RSS Root Sua Squares RWT Refueling Water Tark SA Safety Analysis SIAS Safety Injection Actuation Signal l
STS Standard Technical Specification Tech Spec Technical Specification
tage x ARKANSAS POWER & LIGHT COMPANY ARKANSAS NUCLEAR ONE - UNIT 2 DETERMINATION OF PLANT PROTECTION SYSTEM TRIP SETPOINT VALUES
1.0 INTRODUCTION
1.1 Scope By References 4.1 and 4.2 the Nuclear Regulatory Commission (NRC) requested specific setpoint related data for the Arkansas Nuclear One - Unit 2 (ANO-2) Plant Protection System (PPS) from Arkansas Power 6 Light Company (AP&L). This document provides the requested information and also describes the Combustion Engineering (CE) set-point methodology used to determine ANO-2 setpoints.
This methodo-logy was established to assure consistency with current licensing requirements and industry standards.
Section 2.0 describes the present CE method of determining protec-tion system setpoints that is used to assure consistency with cur-rent requirements and standards.
This section begins by explaining, in general, how setpoints are determined and how the different aspects of setpoint determination are related to the Safety Analysis (SA) and to the plant technical specifications (Tech Specs). The remainder of Section 2.0 describes in more detail the specific components of this CE setpoint methodology.
Section 3.0 provides the specific data requested by References 4.1 and 4.2.
The section begins with an explanation of the data in the tables and relates the data to the explanation of the CE setpoint methodology previously given. The remainder of Section 3.0 consists of tables which contain the requested information.
Section 4.0 lists the references referred to in this document.
1.2 Background
This document provides the specific information requested of AP&L by References 4.1 and 4.2.
This information is contained in Tables 1-7 at the end of the report.
Section 3.0 describes how the infor-mation is compiled in the tables and provides a one-to-one correla-tion between the specific information requested in References 4.1 and 4.2 and the data in the tables.
Information contained in this document describing methods of determining protection system set-points and specific data requested in References 4.1 and 4.2 were supplied to Arkansas Power and Light by Combustion Engineering.
For the purpose of clarification in this document, where certain examples are given a high trip setpoint is shoen. The information presented also applies to a low trip setpoint, however minor modi-fications to the example would be required to be specifically applicabic.
tage L 2.0 SETP01NT METHODOLOGY s
2.1 Basic Description a
Figure i shows in block diagram the CE setpoint methodology.
This section describes the CE method of setpoint calculation.
The ANO-2 Reactor Protection System (RPS) uses a Core Protection Calculator (CPC) to generate two of the eleven trip signals.
The CPC is a f
digital co=puter system which uses a method that differs in some respects from the method used for the other trip functions to ensure all equipment uncertainties are accommodated in a decision to initiate a reactor trip.
Section 2.5 describes the CPC method of uncertainty accommodation in particular. The other sections of Section 2.0 discuss the setpoint methodology applicable to the non-CPC portion of the RPS and the entire ESFAS.
As part of obtaining an operating license (OL), a Safety Analysis is performed to show that the consequences of Design Basis Events (DBEs) will be acceptable.
This Safety Analysis assumes protective action is initiated at the point where the process variables reach established setpoints. These setpoints assumed in the Safety Analy-sys are defined as Analysis Setpoints (ASP).
A detailed equipment error calculation is the,n performed which statistically combines the individual uncertainty components asso-ciated with the specific equipment to determine the margin required l
between the Analysis Setpoint and the setpoint set into the equip-l ment.
The Analysis Setpoint is then adjusted in the conservative direction by this calculated margin and the resulting value is defined as the Equipment Setpoint (ESP).
The Equipment Setpoint becomes part of the plant technical specifications (Reference 4.4) and represents the value the technician is to set into the equipment during required calibration and maintanance.
As an integral part of the equipment error calculation, a number is also determined which represents the maximum expected equipment drift over a specified period between calibrations.
The Equipment Setpoint is now adjusted toward the Analysis Setpoint by the amount calcula-ted for equipment drift and the resulting nueber is the Allowable Value (AV).
This Allowable Value also becomes part of the plant technical specifications and represents the value to which the equipment can drift between calibrations and still be consistent with the Safety Analysis.
Thus the CE setpoint methodology results in an Equipment Setpoint and an Allowable Value which, assuming the equipment operates as designed, assure that the equipment wi,ll initiate protective action conservatively relative to the Analysis Setpoint used in the Safety Analysis.
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The remainder of Sectien 2.0 discusses in greater detail the specific ccmponents of the CE " explicit" setpoint methodology.
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As a basic requirement, setpoints must be chosen to (1) ensure initiation or protective action as required to show acceptable consequences for safety related Design Basis Events (DLEs),
and (2) to ensure that performance related DBEs'can be accom-modated without initiating protective action.
Refer to Figure 2 during the discussion on determining Analysis Setpoints.
As an initial step in setpoint determination the equipment errors for each trip function are estimated using 'nown equip-ment characteristics, the anticipated environmental effects, and using knowledge gained in previous efforts for different plants.
Additionally, the operating ranges for the measured parameters are determined for nornal steady state conditions and during performance related DB8s.
This setpoint is called the Nominal Value and represents the approximate value of the final expected set-point.
The Nominal Value is used in the Preliminary Safety Analysis Report (PSAR) which is issued well before the final Safety Analysis is completed and incorporated into the Final Safety Analyses Report (FSAR). The Nominal Value is then adjusted, again considering the estimated total equipment error, to result in a value that represents the expected most limiting point at which a protective action would be initiated if the equipment setpoint was set at the Nominal Value.
This resulting value is the Analysis Setpoint which is input to the Safety Analysis.
Analysis Setpoints are in some cases results of parametric studies conducted until a setpoint is determined which will result in an acceptable Safety Analysis and li.
acceptable plant performance.
Some events analyned in the Safety Analysis result in a more severe environment for protection system equipment than other events.
As a result the expected total equipment error can be different for different events (i.e., event specific).
There-fore, a trip function can havc different Analysis Setpoints for different events.
The Analysis Setpoints are used in the Safety Analysis to show acceptabic consequences for the events analyzed.
In the Safety Analysis, the Analysis Setpoint is the value of the measured parameter at the measurement point at which protection system actuation is assumed to start.
The Safety Analysis is described in the Final Safety Analysis Report (FSAR) (Reference 4.3) and is part of the documentation required to receive an operating license.
Tne final Analysis Setpoints used in the Safety Analysis are then used in the setroint calculation to determine Equipment Setpoints and Allowable Values as described in subsequent sections of this report.
. M M xu Page 4 2.3 Equipment Errors 2.3.1 General Current setpcint requirements and good engineering practice dictate that all factors which can affect' the operation of equipment by considered when determining errors in the setpoint calculation.
In-the CE setpoint e.ethodology, each error com-ponent that can have an impact on equipment performance is determined separately and then the individual errors are combined in a statistically valid method to arrive at a total equipment error.
The individual errors are plant-specific and equipiaent-specific an'd thus must be determined for each plant on a case-by-case basis.
The following paragraphs describ'c :he individual error components.
These are:
1.
PPS cabinet calibration error; 2.
PPS cabinet perioulc test error; 3.
Process equipment calibration error; 4.
Process equipment periodic test error; 5.
Accident environment error; 6.
Process error; 7.
Dyna:ric Allowance.
Fol1 wing-this 13 a description of'the method used to combine 9
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the individual errors to arrive at a total equipment error.
For means of setpoint calculation, the PPS is divided into two major regions as shown on, Figure 3.
The first region is the process equipment.
This c'nsists of the sensor, transmitter, o
power supply and signal p[ocessing equipment - all equipment up 'o the PPS cabinet.
The second region is the PPS cabinet J
itself.
Tliis is consistent with the surveillance requirements in the-plant technical specifications-(Reference 4.4) which reqaire a-channel functional check (i.e., PPS cabinet) month?.y and a channel calibration'(i.e., process equipment and PPS cabinct) eve,ry 18 months.
2.3.2 Individuel Errors s
2.3.2..
PPS Cabinet Calibratien Error.
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This is ah9 error inherent in the PPS cabinet instru-nentation;pn,4 represents the error that would have to
'be accounted'for if the instrumentation was required
-for pyotective action immediately after the calibration procedure was performed.
This error is determined for
- be'3pecific equipment installed in the PPS cabinet frvq information supplied by the manufacturer and octucl LM.ibration rejuireme'its on the equipnent.
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2.3.2.2 PPS Cabinet Periodic Test Error This error accounts for the expected drift of the PPS cabinet setpoint over the period from when the setpoint is set until the monthly Channel Functional Check is performed to check the setpoint. When determining this error, the following aspects are considered:
the error associated with setting and checking the setpoint, errors because of the dif-t ference in PPS cabinet environment at the time the setpoint is checked and the environment when the setpoint was set, and errors due to anticipated drift of the PPS cabinet equipment.
The component errors are combined to determine the PPS cabinet periodic test error in a manner similar to that described later in Section 2.3.3 for determining total equipment errors.
l The PPS cabinet periodic test error is calculated using l
information supplied by the equipment manufacturer and j
from actual testing of the equipment.
2.3.2.3 Process Equipment Calibration Error This error is analogous to the PPS calibration error but applies to the process equipment as shown on Figure 3, vice the PPS cabinet.
This is the error inherent in l
the process equipment and represents the error that j
would have to be accounted for if the equipment was required for protective action immediately af ter the calibratien procedure was performed. As with the j
previous errors, the process equipment calibration
. crror is determined ~for the specific equipment instal-led at the plant from information supplied by the manufacturer and actual calibration requirements on the equipment.
2.3.2.4 Process Equipment Periodic Test Error This error is analogous to the PPS cabinet periodic test error but applies to the process equipment. The error accounts for the expreted drift of the equipment 1
during the time between channel calibrations, which are performed as a minimum every 18 months as required by the plant technical specifications (Reference 4.4).
The same aspects are considered when calculating this error as are considered when determining the PPS cabinet periodic test errur described above and the components are combined in a similar manner.
1 2.3.2.5 Accident Environment Error During certain analyzed events the atmosphere in the containment is affected, and/or seismic events are considered to occur sinultaneously. This change in environment introduces additional errors in the pro-i cess equipnent which must be considered in the over-all setpoint calculation.
Exampics of specific environmental ef fects on equipner.t crror which arc m -s v.
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considered are:
temperature effect, pressure ef fect, reference leg effects, seismic effects and radiation effects. The individual errors are then combined in a manner similar to that used to calculate total equipment errors described in section 2.3.3.
The environment considered when determining these errors is the worst case environment calculated or postu-lated to exist up to the time of the required reactor trip or Engineered Safety Features (ESP) actuation.
This environment can be different for different events analyzed.
In most cases of setpoint calculation, the accident environment error calculation for process equipnent uses the environmental conditions that result in the largest errors, thus adding additional conserva-tivism (i.e., greater margin) for the events with smaller errors.
In some cases, however, the accident environment errors for some events are much larger than for those events with little or not containment environment change.
In these cases, specific errors are calculated for different events.
The event speci-fic errors are then used in calculating total equipment errors (described later in this section) which also become specific.
2.3.2.6 Process Error This error accounts for the uncertainty of the value of the process para =cter (e.g., neutron flux power) at the sensor.
In most cases the errors which exist between the actual process parameter and the value at the sensor are incorporated into the Safety Analy-sis instead of beco=ing part of the setpoint calcu-lation.
When part of the setpoint calculation, the process errors are combined with the other equipment errors to determine the total equipment error as described later in this section.
2.3.2.7 Dynamic Allowance In certain cases it is determined that the actual delay time for the equipment is longer than the time used in the Safety Analysis.
In these cases a dy-namic allowance may be incorporated into the setpoint to compensate for this time response difference.
Refer to Figure 4 for a simplified representation of the dynamic allowance discussed here.
As part of the Safety Analysis, a time delay is used to account for the delays inherent in the PPS equipment.
For the RPS this time delay represents the time from when the process value at the sensor reaches the trip point to when the Control Element Drive Machanism (CEDM) coil flux has decayed sufficient 1v so that the Control Element Assemblies (CEAs) begin to move into the core.
IPage F i
f for t TSFAS this gime delay represents the. time from en the process value at the sensor reaches the actuation point to when the actuation signal is output from the Auxiliary Relay Cabinet.
When the actual PPS equipment is tested,* time delays of'the various components are determined and verified.
The total time delay is then determined. As has been stated, in certain cases the actual time delay for the equipment may be longer than that used in the j
Safety Analysis.
The reason for this difference is that the expected dynamic response of the sensor is slower thar. That originally assumed as. Input to the Safety Analysis.
To assare, then, that a protective action occurs at or before the time assumed in the Safety Analysis, the Equipment Setpoint is altered in a conservative direction to compensate for the l
, sensor response characteristics. {
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) This resulting dynamic allowance is then conservative for all transients with a rate of change less than that used in the calculation.
2.3.3 Total Equipment Error After the individual error components have been determined, I
they are then conbined to arrive at a total equipment error which is used in calculating Equipment Setpoints.
Each individual error can consist of both random and non-random components.
Random errors are errors of uncertain algebraic sign (+ or -).
Non-random errors are errors having a known sign. [
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total error is a combination of a l
non-random component.
The total equipment error represents the maximum error calculated that could occur at any time during the periodic calibration interval for the limiting event for which the function is r.cquired to operate.
As dis-cussed previously, in some cases different accident environment errors are calculated for different events analyzed.
In these cases different total equipment errors are then calculated using the different accident environment errors.
These total equipment errors are event specific and are used as such when determininr. Equipment Setpoints as discussed in Section 2.4.1.
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UElWD 2.6 Setpoint Determination 2.4.1 General The plant technical specifications (Reference 4.4) have Equipment Setpoint and Allowabic Value requirements for the PPS equipment.
The Safety Analysis uses Analysis Sctpoint values for the PPS equipment as part of shoning acceptable consequences for the events analyzed.
Equipment Setpoints, Allowable Values and Analysis Sctroints are tied together in the setpoint deter-mination process of the setpoint calculation.
2.4.2 Equipment Setpoint As discussed in Section 2.3.3, a total equipment error is determined for each PPS function.
This represents the maximum error which must be accommodated to account for all the indi-vidual errors which can affect the accuracy of the equipment being used.
In some cases, different total equipment errors are calculated fer different events analyzed. To ac'comodate all errors in the setpoint calculation, then, the Analysis Setpoint is changed in a conservative direction by the amount of the total equipment error to arrive at the Equipment Sctpoint.
When different total equipment errors and different Analysis Setpoints are determined for different a,nalyzed events, the event specific Analysis Setpoints are changed in a conservative direction by the corrcaponding event specific total equipment errors. The most conservative resulting value is then used as the Equipment Setpoint so that in all cases a conservative setpoint calculation is assured.
See Figure 5 for a represen-tation of Equipment Setpoint calculations where different events are analy:cd separately.
The calculated Equipment Setpoint for each PPS function becomes part of the plant technical specifications (Reference 4.4) ar.d represents the value set into the equipment during calibration.
The PPS cabinet equipment, like all analog equipment of this type, cannot be set exactly at a specified value.
There are errors inherent in the bistable itself, and in the power sup-plies and voltmeter used to set and check the setpoint.
These errors have been included in the total equipment error as the PPS cabinet calibration error discussed in Section 2.3.2.1.
To be consistent with the STS format [
] Equipment Sctpoints shown in the plant technical specifications (Reference 4.4) are all prefaced with a < or >, depending on whether the setpoint is above or below the normal operating range, respec-tively.
This limits setting the, Equipment Setpoints to no less conservative than the value shown in the technical specifica-tions,[
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Page 9 2.4.3 Allowabic Value As discussed in Section 2.3.2.2, the PPS cabinet periodic test error represents the maximum anticipated drif t of the PPS cabi-net equipment during the specified period of time between cali-brations. This error was used when calculating the total equip-cent error which was used to determine the Equipment Setpoint.
The Eqripment Setpoint is now adjusted toward the Analysis Setpoint by the amount of the calcuisted PPS cabinet periodic test error. The resulting value is the Allowable Value listed in the plant technical specifications (Reference 4.4).
As required by the technical specifications, if, upon checking a setpoint, it is found to be less conservative than the Allow-able Value, the channel must be declared inoperable, specific action must be taken and the equipment setpoint must be reset.
By calculating the Allowabic Value as described above, the problem of anticipated equipment drift causing actual setpoints which are inconsistent with the Safety Analysis and the setpoint calculation is virtually eliminated.
2.4.4 Technical Specifications For each PPS function, the Equipment Setpoints and Allowable Values which have been calculated to assure that the equipment will operate as assumed in the Safety Analysis are then incor-porated into the plant technical specifications.
As part of the setpoint calculation to arrive at the Equipment Setpoints and Allowable Values, certain assumptions were made.
These include:
the accuracy of the equipment used, the cali-bration intervals, the method of calibration, and other equip-ment characteristics.
The equipment calibration proccdure assures that the assumptions used in the setpoint calculation are verified.
2.5 Core Protection Calculator Setpoints 2.5.1 Cencral The'ANO-2 Reactor Protection System uses a Core Protection Calculator (CPC) to generate two of the eleven reactor trip signals.
For the purpose of this report, when the Core Protection Calculator is referred to, it includes the Con-trol Element Assembly Calculator (CEAC) as part of the CPC system. The RPS inputs and trip functions are shown in Pigure 6.
The CPC is a digital calculator system which uses a method which differs in some important aspects from the method used for the other trip functions to ensure that all equipment uncertainties are accommodated in the decision to initiate a reactor trip.
Methods of incorporating uncer-tainty compensation into the CPC have been addressed in detail in documents previously submitted to the NRC (References 4.3, 4.5, 4.6, 4.7, 4.8, 4.9, and 4.10).
The following discussion summarizes the information presented in these documents.
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2.5.2 CPC Uncertainty Camponents Calculaelons performed by the CPCs are modified to account for the following uncertainties and allowances:
1.
Measurement Uncertainties; 2.
Algorithn Modelling Uncertainties; 3.
Algorithm Constants Uncertainties; 4.
CPC Processing Uncertainty; 5.
Static Allowances; 6.
Dynamic Allowances.
A general discussion of each of the listed items is now given.
2.5.2.1 Measurement Uncertainties Measurement uncertainties are the effect on the CPC response due to sensor and measurement channel characteristics.
As shown in Figure 6, the CPC teasured inputs include:
1.
Reactor coolant cold leg temperature; 2.
Reactor coolant hot leg temperature; 3.
Pressurizer pressure; 4.
Reactor coolant pump (RCP) rotational speed; 5.
Ex-core detector nuclear flux; 6.
CEA position.
A measurement uncertainty is calculated for each of the above CPC inputs (and factored into the CPC algorithms, as will be described in Section 2.5.3).
The uncertainties calculated for the CPC measured inputs are based on manufacturer's instrument specification, type testing, calculations and pre-vious operating experience.
The specific uncertain-ties calculated contain allowances for all components in the measuretent channel including sensor, trans-mitter, power supply, dropping resistor, multiplexer and analog to digital converter (A/D).
Figure 7 shows in block diagran where the CPC fits into the ANO-2 PPS and what portions of the PPS are considered when deter-mining CPC neasurement uncertainties.
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Page 11 For each component in the measurement channel, instru-ment linearity, repeatability, environmental effects, and drift between calibration periods are considered in the calculation of measurement uncertainties.
The resulting measurement channel uncertainty is analogous to the uncertainty that would be obtained for the non-CPC portion of the RPS (described in Section 2.3) if the following uncertainties were combined:
1.
Process equipment calibration error; 2.
Process equipment periodic test error; 3.
Accident environment error; 4.
Process error.
The method of combining the individual components _to arrive at the measurement channel uncertainty is simi-lar to the method described in Section 2.3.3.
The resulting uncertainty includes a random component and a non-random component.
2.5.2.2 Algorithm Modelling Uncertcinties Algorithm modelling uncertainties address the accuracy with which CPC algorithms replicate the results of design codes, "best estimate" measurements and/or "best esti-mate" calculations.
2.5.2.3 Algorithm Constants Uncertainties Algorithm constants uncertainties address the accuracy of the measurements and/or calculations used to obtain the constants in the algorithm.
This type of uncertainty depends upon both the accuracy of the instruments used in the measurements as well as the technique used to process the measurements and can consist of both random and non-random components.
2.5.2.4 CPC Processing Uncertainty The CPC processing uncertainty is attributable to CPC (computer) processing and addresses the effects that scaling, round-off and bit manipulation have on the CPC computed result. Testing of the CPCs and calcula-tions provide the infor=ation needed to determine this uncertainty.
Comparison of actual CPC resonse to the results obtained using the CPC algorithm with the higher resolution computing facility used in the design process and the Safety Analysis provides a mechanism for quantifying and characterizing the pro-cessing uncertainty.
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2.5.2.5 Static Allowances Static ' Allowances account for the effect on the margin to fuel design limits of (1) variations in parameters not monitored by the CPCs, and (2) allowed variations (action thresholds or deadbands") in the parameters monitored by the CPCs.
The only parameter that falls a
into the first category is the azimuthal power tilt magnitude.
An exampic of a parameter in the second category is the deadbands on CEA deviation provided in the CPC.
2.5.2.6 Dynamic Allowances Dynamic Allowances account ior the tine delays associa-ted with the'following:
1.
CPC sensor delays; 2.
CPC sampling intervals; 3.
CPC processing times; 4.
PSS trip logic delays; 5.
CEA holding coil decay times; 6.
CEA insertion times; i
7.
Transient delays associated with the heat flux and stored energy response following CEA insertion.
Accounting for thesc' delays in the decision to initiate a low DNBR or high local power density (I.PD) reactor trip ensures that the transient analyzed in the Safety Analysis will be terminated before the actual fuel design lirdts are exceeded.
2.5.3 Accommodating CPC Uncertainties 2.5.3.1 Ceneral Method The CPCs are designed with the capability of accommo-dating uncertainties in a variety of ways with the choice being dependent upon the nature of the uncer-tainty component. Measurements can be biased prior to use in calculations to account for uncertainties and/or allowances; calculated results can be indivi-dually modified; or selected calculated values cen.
-be modified to account for the effect of all of tne uncertainty components on the final trip comparison.
The optimum method of accommodating uncertainties in the CFC will simultaneously ensure conservatism and maximize operating flexibility.
Page 13 The method cf accommodating CPC uncertainties for the ASO-2 Reactor Protection System involves determining constants which then become part of the CPC program.
These coistants result fren combining the individual uncertatuties discussed in Section 2.5.2 in a manner which ensures all uncertainties are accommodated.
The combination of individual uncertainties to arrive at the CPC constants is performed similar to the method described in Section 2.3.3 for combining errors in the non-CPC portion of the protection system.
The CPC trips are low DNBR and high Local Power Density (LDP).
Constants are determined for use in the DNBR calculation and separate constants are determined for use in the LPD calculation.
The following sections discuss the constants used in the DNBR and LPD calcu-lations, respectively.
2.5.3.2 DNBR Uncertainty Constants There are two uncertainty constants used in the DNBR calculation which, in total, ensure a low DNBR. trip response that is conservative relative to the Safety Analysis.
These are:
1.
Uncertainty bias for power used in the DNBR calculation (BERR2)*
2.
Power uncertainty factor used in the DNBR calcu-lation (BERRI).
Region-dependent algorithm uncertainty allowance (E(J)).
2.5.3.2.1 Uncertainty Bias for Power used in the DNBR calculation (BERR2)-
The uncertainty bias for power used in the DNBR calculation accounts for the uncertainty inherent in the inputs to the power calculation in the CPC.
This includes the power calibration uncertainty and the dynamic uncertainty in both the neutron flux power and the thermal power. These uncer-tainties are measurement uncertainties and dynamic allowances (as discussed in Sections 2.5.2.1 and 2.5.2.6, respectively).
The un-certainty bias for power used in the DNBR calculation is added to the calculated power level as:
POWER
= POWERCALC + EERR2 DNB where POWERDNB = P uer level input to the DNBR calculation corrected for power me :surement uncertainties.
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Page 14 POWER CALC = Power level calculated from neutron flux or thermal measurements.
BERR 2
= Uncertainty bias for power used in the DNBR calculation.
2.5.3.2.2 Power Uncertainty Factor Used in the DNBR Cal-culation (BERRI).
Region-dependent Algorithm Uncertainty Allowance (E(J)).
These factors account for the uncertainties not accounted for by the previous constant.
These two factors are discussed as one because they
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are determined together and they are applied together in the CPC algorithm, as shown below.
For enhanced operating flexibility, the opera-ting space in which the DNBR is calculated is divided into nine different regions depending on inlet coolant temperature, coolant pressure, axial shape index, and integrated radial peaking factor. The region-dependent algorithm uncer-tainty allowance is also determined separately for each region and nine separate uncertainty allowances result, which are then used in the DNBR calculation.
The method of combining the individual uncertainty components to determine the actual values used for these constants is similar to the method described in Section 2.3.3 of this report.
The power icvel corrected for power measurement uncertainties is then multiplied by the appropriate constants to result in the power level used in the DNBR calculation, as:
POWERDNB ADJ = POWERDNB *BERR1 *(1+E(J))
where POWERDNB ADJ= Corrected power level used in the DNBR calculation BERR1
= Power uncertainty factor used in the DNBR calculation.
E(J) = Region-dependent algorithm uncer-tainty allowance.
OR:
POWER
= (POWERCALC + BERR2 ERR 1 DNB ADJ
- =
2.5.3.3 Local Power Density Uncertainty Constants There are two uncertainty constants used in the LPD calculation which, together, ensure a high LPD trip response that is conservative relative to the Safety Analysis. These are:
1.
Uncertainty bias for power used in the LPD calculation (BERR4) 2.
Power Uncertainty factor used in the LPD calculation (BERR3) 2.5.3.3.1 Uncertainty Bias for Power Used in the LPD Calculation (BERR 4 The uncertainty bias for power used in the LPD calculation accounts for the uncertaintics inherent in the power measurement process input to the CPC. This includes the power calibra-tion uncertainty and the dynamic uncertainty in both the neutron flux power and the thermal power.
These uncertainties are measurement ~
uncertainties and dynamic allowances (as dis -
cussed in Sections'2.5.2.1 and 2.5.2.6, respec-tively). The uncorrected power icvel used in the LPD calculation is the same as that used in the bNBR calculation and the uncertainty compo-nents of the uncertainty bias for power used in the LPD calculation are identical to the compo-nents of the uncertainty bais-for power used in the DNBR calculation.
Thus, the value of the two constants are the same and they are applied in an identical manner. The uncertainty bias for power used in the LPD calculation is added to the calculated power level as:
POWERLPD = POWERCALC + ERR 4.
where POWERLPD = Power level input to the LPD cal-culation corrected for power measurenents uncertainties.
POWER
= Power level calculated from neutron CALC flux or thermal measurements B
= Uncertainty bias for power used in ERR 4 the LPD calculation.
WQVW 2.5.3.3.2 Power Uncertainty Factor Used'in the LPD Calculation (BERR3)
The power uncertainty factor used in the LPD cal-ulation accounts for the uncertainties not accounted I
for by the LPD-power measurements.
This is ana-logous to the DNBR constants BERR1 and E(J) des-cribed in Section 2.5.3.2.3.
Unlike the DNBR constants, however, one analysis is performed for the entire LPD operating space.
Thus only one power uncertainty factor is used in the LPD calcu-lation results for the entire region.
The method of combining the individual uncertainty components to determine the constant is similar to the method described in Section 2.3.3 of this report.
The power level already corrected for power measure-ment. uncertainties is then multiplied by the power level used in the LPD calculation, as:
POWER LPD ADJ = POWERLPD ' ERR 3 where POWER Corrected power level used in
=
LPD ADJ the LPD calculation ERR 3 Power uncertainty factor used B
=
in the LPD calculation.
OR:
POWERLPD ADJ = (POWERCALC + BERR4)
BERR 3 2.5.3.4 Technical Specifications As shown in the Tech Spec (Ref. 4.4) and in Table 5 of-this report, the Analysis Setpoint, Equipment Setpoint i
and Allowable Value for the low DNBR trip are identical.
This is also true for the high Local Power Density trip function.
As has been discussed in Section 2.5.3, all-uncertainties in the CPC' system, including dynamic responses and equipment drift are' accommodated as cor-rection constants in the calculation of DNBR and Local Power Density. This ensures that when the calculated DNBR or LPD reaches its respective trip setpoint value and the RPS sends out a reactor t' rip signal, the re-sponse of the protection system will provide protection during the Design Basis Events analyzed.
Because of this method of accommodating uncertainties in the CPCs, for each CPC trip function, the Equipment Setpoint is identical to the Analysis Setpoint used in the Safety
. Analysis.
Also, the CPC, being a digital computer sys-tem, is not subject to setpoint drift like the non-CPC analog trip functions.
Thus no allowance for setpoint drift is required and the Equipment Setpoint-and Allow-able Value are identical for each CPC trip function.
1 t
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~ Pagn 17 2.6 Equipment Calibration 2.6.1 Basic Description The CE " explicit" setpoint methodology determines Equipment Set-points and Allowable Values for the PPS trip functions.
These a
numbers then become part of the plant technical specifications (Ref. 4.4).
b* hen the setpoint calculation is performed, it is
~
assumed the equipment will be maintained and will operate in accordance with the technical specification requirements.
These requirements include:
surveillance requirements on how often equipment calibration must.be performed; setpoint data which specifies the value the equipment is to be set to and the value allowed during scheduled testing; and response time requirements on how rapidly the equipment must operate.
The setpoint procedure is an input to these requirements in the plant technical speci-fications. This ensures that the specific data in the requirements is consistent with the assumptions used in the setpoint process.
To ensure, then, that the protection system equipment continues to operate in a manner consistent with the setpoint calculation, the plant staff maintains the equipment in accordance with the requirements set forth in the plant technical specifications.
2.6.2 CPC Calibration 2.6.2.1 General As previously described, the CPC is a digital cceputer system.
It processes measured input parameters and generates a low DNBR or a high Local Power Density reactor trip actuation signal when the calculated values reach a predetermined setpoint.
The difference between these trip functions and the other trip func-tions in the Plant Protection System is that the decision to initiate a reactor trip is performed in a digital computer in the CPCs instead of by reaching a predetermined value in an analog bistable.
For calibration and testing purposes the CPC trip channel is divided into two parts as shown in Figure 7.
The first part is the process equipment which provides the input signals to'the CPC computer and the second part is the CPC computer system itself. These will now be t
discussed individually.
l 2.6.2.2 CPC Process Equipment Calibration The CPC process equipment includes all equipment in the chain from the sensor up to and including the analog to digital converter (A/D) which provides the digital measurement signal to the CPC (see Figure 7).
Except for the A/D. this is identical to the non-CCP portion of the protection system previously discussed. The A/D is treated in a manner similar to the rest of the l
l
W process equipment in the setpoint calculation proccas.
That is:
all uncertainties are considered which can affect the' accuracy of the A/D; these uncertainties are combined to determine an A/D total uncertainty; and the A/D total uncertainty is combined with the other process measurement uncertainties when deter-mining the total process measurement uncertainty.
As with the rest of the process equipment, certain assump-tions must be made about the operation, calibration, and testing of_the A/D when determining its uncertainty.
These assumptions are verified during plant operation to ensure the setpoint calculation remains valid.
2.6.2.3 CPC Computer System Calibration The remainder of the CPC portion of the protection system is the CPC computer system itself.
This is different from the rest of the RPS trip decision logic in that the CPC is a digital computer.
As such the rPC trip setpoint is not subject to drift and thus histabic drift was not considered as part of the CPC uncertainty calculation discussed in Section 2.5.
However there are numerous similarities between the CPC and the non-CP,C portions of the pro-tection system concerning equipment calibration and the majority of the preceding discussion applies.
the CPCs.
k' hen determining equipment uncertainties for the CPCs (see Section 2.5.2), certain assumptions are made that require verification to ensure the CPC method of accom -
modatinguncertaintiesremainvalid.[
+
As with the rest of the protection system, these assumptions are documented (during the design process).
It is then ensured that the technical specifications
. include requirements that, when met, u111' verify these assumptions.
Because the CPC is a digital computer system, the algorithm is not subject to drift.
As
.s u c h, the monthly Channel Functional Test required by the technical specification is different from the
LdQJd' W s
tests performed on th non-CPC channels.
For the CPCs this involves such thines as verifying, one-for-one, that the information stored in protected memory agrees with the data on the test disc, and putting in test inputs and checking the CPC outputs to ensure they are correct.
i l
l l
l l
l s***mww
utUm 3.0' DETAILED SETPOINT DATA 3J1 NRC Request On March 22, 1977, the NRC sent a letter of the subject " Arkansas Nuclear One - Unit 2 Instrument Setpoints" to-AP&L (Ref. 4.1).
This letter stated that NRC review of facility operating experience indi-cates the need for additional information regarding the proper scice-tion of instrumentation trip setpoint values.
This conclusion is-supported, the Ictter states, by the large number of Licensee Event Reports (LERs) received by the NRC related to instrument setpoint drif t beyond the limits permitted by the facility technical speci-fications. As a result, the NRC requested explicit information concerning each RPS and ESF instrumentation channel trip setpoint value. The specific information requested was:
1.
The technical specification trip setpoint value; 2.
The technical specification allowabic value; 3.
The instrument drift assumed to occur during the interval between technical specification surveillance tests; 4.
The components of the cumulative instrument bias;
~
~
5.
The minimum margin between the technical specification trip setpoint and the trip value assumed in the accident analysis.
Additionally, on September 1, 1978, the NRC issued Amendment 1 to the ANO-2 operating license (OL) (Reference 4.2).
In the OL the the NRC also requested explicit setpoint related information for incorporation into the technical specifications.
The three items requested in the OL are identical to items 3-5, respectively, of the above list.
As can be scen, the information requested is purely numerical data.
This report has explained the CE " explicit" setpoint methodology so that the data, when presented, will be more easily understood.
Tables 1-7 contain the required. data.
The remainder of Section 3.0 is an explanation of these tables and ties the data presented with the CE setpoint methodology previously discussed.
3.2 Explanation of Tables 3.2.1 General Tables 1-7 contain' explicit data on the RPS and ESFAS used in the Equipment Setpoint determination process. This provides the information requested in Reference 4.1 and 4.2.
Tables 1-4 contain information for the non-CPC portion of the Plant Protection System and Tables 5-7 contain the requested infor-mation for the CPC portion.
Many values given in the tables contain both a random'(+) and a non-random (+) component.
For the non-random components, as used in this report, the + signifies that the uncertainty is one-sided in the non-conservative direction and included in the setpoint calculation.-
The following Sections 3.2.2 - 3.2.6 provide an explanation of the columt.s of data contained in Tables 1 - 7.
Section 3.2.7 discusses additional items by PPS function where further clarification is helpful.
3.2.2 Table 1 Table 1 contains the Equipment Setpoint, Allowable Value and the Drift Allowance for each discussed PPS function.
The Equipment Setpoint and the Allowable Value data is obtained directly from the plant technical specifications (Ref. 4.4).
The Equipment Setpoint is the value of the trip setpoint actually set into the PPS cabinet during calibration, and corresponds to the data requested in item 1 of the NRC letter (see Section 3.1).
The Allowable Value is the limit on the trip setpoint at any time during normal plant operation and is checked during the monthly Channel Functional Test as required by the technical specifications'.
Operation with a trip setpoint conservative with respect to the Allowabic Value is necessary to assure the equipment will operate as assumed in the Safety Analysis. The Allowable Value data presented corresponds to item 2 of the NRC request.
The third column contains the Drift Allowance and corresponds to item 3 of the NRC request and item 1 of the ANO-2 OL.
This is the difference between the Equipment Setpoint and the Allowable Value and represents the equipment drift calculated that may occur between technical specification surveillance tests.
3.2.3 Tables 2 and 3 Tables 2 and 3 contain the values for the components used in the total equipment error calculation. This corresponds to item 4 of the NRC request and item 2 of the ANO-2 OL.
A discussion of c'ach of these components is contained in Section 2.3 of this report.
Table 2 contains PPS cabinet and PPS teasurement channel data.
For each equipment arca the uncertainty calculated for cali-bration and periodic testing is listed.
The calibratie-uncertainty accounts for basic ipaccuracies in the equipment used during calibration and in the equipment being calibrated.
The periodic testing procedure uses the same test equipment as during calibration. Therefore, the calibration uncertainty is included in the calculation of the periodic test uncertainty in addition to the other components, as discussed in Section 2.3.
As a result, the calibration uncertainty data contained in Table 2 is not explicitly included, again, in the total error calculation.
i The PPS cabinet periodic test error in Table 2 is used indirectly to determine the Drift Allowance data given in Table 1.
The random and non-random components of the periodic test error are combined to determine the calculated equipment drift between calibrations.
This is applied to the Equipment Setpoint toward the Analysis Setpoint to give the Allowable Value.
Because of mathe-matical round-off in non-significant figures, the Drift Allowance and the PPS periodic test error are not iden-tical in every case.
Some Drift Allowances are larger than tt PPS periodic test error in the third decimal place; an apparent non-conservative result, as this would seem to allow the actual setpoint to come too close to the Analysis Setpoint.
Figure 8 cxplains how this can result in the setpoint calculation and still be a conservative result.
Table 3 contains data for the remainder of the uncertainty components as discussed in Section 2.3.
3.2.4 Table 4 Table 4 contains the Analysis Setpoint data and the margin between the Analysis Sctpoint and the Equipment Sctpoint.
The Analysis Setpoint is the value used in the Safety Analy-sis at which protection system actuation is assumed to start.
The margin between the Analysis Setpoint and the Equipment Setpoint is the mathematical difference between the two values. This corresponds to item 5 of the NRC request and iten 3 of the ANO-2 OL.
In all cases this margin is larger than the total equipment error determined in the setpoint calculation.
This ensures that a trip actuation will occur prior to the point used in the Safety Analysis.
3.2.5 Table 5 Table 5 contains_the Equipment Setpoint, Allowable Value and Analysis Setpoint data for the reactor trips genera-ted by the CPCs. As shown, all three values for the low DNBR trip are identical as are all three values for the high Local Power Density trip.
The data in Table 5 cor-responds to items 1 and 2 of the NRC request.
Because the Equipnent Fetpoint and Allowable Value are identical, the instrument drift allowance for the CPCs - item 3 of the NRC request and item 1 of the ANO-2 OL - is zero.
The reason for the identical values is explained in Section 2.5.3.4.
Wo@Q E3 Since the CPC is a digital computer system, it is not subject to drift.
Because the Equipment Setpoint and Analysis Setpoir.t are identical, the margin between these two values - item 5 of the NRC request and item 3 of the ANO-2 OL - is zero.
The reasons for these identical values are also explained in Sec-tion 2.5.3.4.
Basically, the margin is incorporated into the CPC computer algorithms rather than in the trip setpoint value itself.
3.2.6 Tables 6 and 7 Tables 6 and 7 contain data on the bias components associated with the measurement signals input to the CPCs.
This corres-ponds to item 4 of the NRC request and item 2 of the ANO-2 OL.
Table 7 also gives the total cllowance for cach input.
This is the value used in the determination of the CPC uncertainty constants.
Table 6 contains measurement channel uncertainties for cali-bration and periodic testing. This is analogous to the same data presented in Table 2.
The A/D conversion allowance represents the calculated uncertainty that must be accounted for at any time between calibrations.
This value was used in calculating the total allowance for each instrument input channel.
Table 7 contains the allowances for environmental effects and software roundoff. Also shown is the total allowance for each instrument channel.
The environmental effects data is analogous to the accident environment data presented in Table 3 for the non-CPC functions.
Sofo are round-off accounts for the conver-sion from the data in the binary register after the A/D to the value in the first register where the data is represented in engineering units. This is included in the total process equip-ment allowance calculation.
The final column of Table 7 con-tains the total allowance for the instrument channel.
This total allowance is the value of the measurement uncertainty discussed in Section 2.5.2.1.
3.2.7 Additonal Notes 1.
liigh Logrithmic Power - RPS: The relation between power and millivolts is not linear for this function.
All error components are determined and combined in millivolts.
2.
High Steam Generator Water Level - RPS: No credit is taken in the Safety Analysis for the operation of this trip function.
3.
Low Steam Generator Water Level - RPS/EFAS:
Two different Analysis Setpoints and two corresponding uncertainty cal-culations were performed.
One calculation was performed specifically for the asymmetric steam generator transients.
Where two values are given, the first is applicable to the is applicable for all other analy::ed eventa. Where only one value is givea, it is applicable to both setpoint calculatiens.
vege ew 4.
liigh Steam Generator Delta Pressure - EFAS: Two esparate sensors are used to determine the pressure difference between the steam generators.
The uncertaintico associated with each sensor are included in the total uncertainty calculation.
5.
Low Refueling Water Tank Level - RAS: Two Analysis Setpoints were used in the Safety Analysis.
A higher icvel actuation was analy:cd to ensure enough borated water was in the containment sump before the RAS was generated. The lower level actuation was analyzed to ensure the RAS was generated while the Refueling Water Tank (RWT) still contains enough water for proper operation. Where two values are listed, the first applies to the lower Analysis Setpoint and the second to the higher Analysis Setpoint. Where one value is listed, it applies to both calculations. The Equipment Setpoint allcws a range for setting, consistent with the calibration uncer-tainties.
6.
CPC RCP Shaft Speed: For both size discs the A/D conversion allowance is not applicable because a binary signal is transmitted to the CPCs.
I
vage L3 4.0 References 4.1 Nuclear Regurotery Commission, " Arkansas Nuclear One - Unit 2 Instrumentation Setpoints", letter to Arkansas Power & Light Company, Docket No. 50-368. March 22, 1977.
4.2 Nuclear Regulatory Ccmmissien, " Arkansas Poser and Light Company, Docket No. 50-368, Arkansas Nuclear One, Unit 2 Paciltiy Operating License", Amendment No. 1, License No. NPF-6, September 1, 1978.
4.3 Arkansas Power & Light Company, " Arkansas Nuclear One - Unit 2 Final Safety Analysis Report".
4.4 Arkansas Power & Light Cempany, " Arkansas Nuclear One - Unit 2 Technical Specifications".
4.5 Arkansas Power & Light Company, " Arkansas Nuclear One - Unit 2 Final Safety Analysis Report, Chapter 7A, Proprietary Version".
4.6 CE Power Systems, Cordhustion Engineering, Inc., "CPC - Assessment of the Accuracy of PWR Safety System Actuation as Performed by the Core Protection Calculators", CENPD-170-P, July, 1975.
4.7 CE Power Systems, Combustion Engineering, Inc., "CPC - Assessment of the Accuracy of PWR Safety System Actuation as Performed by the Core Protection Calculaters", CCNPD-170 Supplement 1-P, November, 1975.
4.8 Nuclear Power Systems, Combustion Engineering, Inc., " Arkansas Nuclear One - Unit 2, Docket 50-368, Final Safety Analysis Report, Proprietary Verisons of Responses to Core Frotection Calculator System Questions 222.59-222.80 and 222.101-222.164",
CEN-35(A)-P, July 26, 1976.
4.9 Nuclear Power Systems, Combustion Engineering, Inc., " Core Protection Calculator System Phase I Design Qualification Test Report", CEN-72(A)-P, October, 1977.
4.10 Nuclear Power Systems, Combustien Engineering, Inc., " Core Protection Calculator Functional Description", CEN-44(A)-P, January, 1977; Supplement 1(P), May, 1977: Supplement 2(P), September, 1977; and Supplement 3(P), September, 1977.
l Page 26 I
f I
TABLE 1 PPS EQUIPMENT SETPOINTS, ALLOWABLE VALUES AND DRIFT ALLOWANCES i
t PPS FUNCTION EQUIPMENT SETPOINT ALLOWABLE VALUE DRIFT ALLOWANCE IIIgb Logarithmic Power 10.75% of rated thermal 10.819% of rated 0.069% of rated Level - RPS power thermal power thermal power
!!igh Linear Power 1123% of rated thermal 1123.712% of rated 0.712% of rated I.evel - RPS power thermal power thermal power liigh Pressurizer Pres-12368 psia 12376.887 psia 8.887 psi sure - RPS Low Pressurizer Pressure
>1740 psia
>1686.75 psia 53.25 psi RPS/CCAS/SIAS
!!igh Steam Generator
<93.6% Water Level
<94.489% Water Level 0.389% Water Uater Level - RPS Level Low Steam Generator Water
>46.5% Water Level
>45.61% Water Level 0.89% Water Level RPS/EFAS Level Low Steam Generator
>728 psia 2706.6 psia 21.4 psi Press-RPS/MSIS/EFAS
!!igh Steam Generator 139 psid 148.35 psid 9.35 psi Delta Press-EFAS liigh Containment Press-118.4 psia 119.024 psia 0.624 psi RPS/CCAS/SIAS/CIAS liigh liigh Containment 123.3 psia 123.624 psia 0.324 psi Press-CSAS Low Refueling Water 6 + 0.5% Indicated
>5.111%, 16.889%
0.889%
Tank Level - RAS Level Indicated Level Indicated Level
pagg 3
- - ~
(.
TABLE 2 l
PPS INSTRUMENT BIAS COMPONENTS.
PPS Fl!NCTION
!!igh Logarithmic Power Level - RPS
!!!gh Linear Power l
Level - RPS Ill;h Pressurizer Pressure - RPS Low Pressurizer Pres-
,;ure-RPS/CCAS/SIAS tilgh Steam Generator Water Level - RPS Low Steam Generator Water Level-RPS/EFAS Low Steam Generator P ress-RPS/flSItf/EFAS liigh Steam Generator Delta Press - EFAS iiigh Containment Press-RPS/CCAS/SIAS CIAS liigh liigh Contain-ment Press - CSAS Low Refueling Water Tank Level - RAS
- - ~ - ~. _. _..
.,.c
Page 28 TABLF, 3 PPS INSTRUMENT llIAS COMPONENTS, CONTINUED n
I PPS FUNCTION liigh I.ogarithmic Power Level - RPS liigh Linear Pewer Level - RPS liigh Pressurizer Pressute - RPS
!.ow Pressuriner Pres-
- ure-RPS/CCAS/S I AS
!!igh Steam Generator Water Level - RPS Lot: Steam Generator Water Level-RPS/EFAS I.ow Steam Generator Press-RPS/MSIS/EFAS liigh Steam Generator DeIta Press-EFAS liigh Containment Press-RPS/CCAS/SIAS/
CIAS l
liigh liigh Containment PRESS - CSAS Low Refueling Water Tank ievel-RAS w *
-r
Page 29 TABLE 4 PPS ANALYSIS SETPOINTS AND SETPOINT MARGINS FIARGIN BETWEEN ANALYSIS SETPOINT PPS FUNCTION ANALYSIS SETPOINT
& EQUIPMENT SETPOINT liigh Logarithmic Power LEVEL-RPS 2% of Rated Thermal Power 11.25% of Rated Thermal Power liigh Linear Power Level-RPS 129% of Rated Thermal 167. of Rated Thermal Power Power liigh Pressurizer Pressure-RPS 2422 psia
> 54 psi iow Pressurizer Pressure-RPS/
1625 psia
_ 115 psia CCAS/SIAS liigh Steam Generator Water 96% Water Level 1 2.4% Water Level Level-RPS
!.ou Steam Generator Water Level 45% & 5% Wa te r Leve l
>1.5 & >41.5% Water Level RPS/l.FAS Low Steam Generator Press-RPS/
678 psia
> 50 psi
?tSIS/ ERAS liigh Steam Gen.erator Delta 100 psid 1 61 pst Press-EFAS tilgli Centainment Press-RPS/
20.7 psia 1 3 psi 2
CCAS/SIAS/CLAS
!!igh !!igh Containment Press-CSAS 25.7 psia 12.4 psi 4
>4.3 & 1 5% Indicated Level Low Refueling Water Tank 1.5 & 10.5% Indicated Leve1-RAS Leve1 i
Paga 30 TABLE 5 PPS CORE PROTECTION CALCULATOR TRIP SET"OINT l>ATA
,._PPS FUNCTION EQUIPMENT SETPOINT ALLOWABLE VALUE ANALYSIS SETPOINT Low DNBR-RPS 1.3 DNBR 1.3 DNBR 1.3 DNBR ilirh Local Power 20.3 kw/ft 20.3 kw/ft 20.3 kw/ft Density-RPS l
l O
S L
6 TABLE 6 PPS CORE PROTECTION CALCULATOR PROCESS EQUIPMENT BIAS COMPONENTS MEASUREMENT CIIANNEL CPC INPUT FUNCTION CALIBRATION PERIODIC TEST A/D CONVERSION Pressurizer Pressure
!!ot Leg Temperature Cold Leg Temperature CEA Position Ex-Core Linear Subchanne's RCP Shaft Speed-28 Inch Disc RCP Shaft Speed-16.969 Inch Disc
~
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4 6
Page 32 TABLE 7 PPS CORE PROTECTION CALCULATOR PROCESS EQUIPMENT BIAS CO:!PONENTS, CONTINUED, AND
?
TOTAL ALLOUANCES
.._.__.__J.
. I
.s;PC INPUT FUI:CTION ENVIRON >1 ENTAL EFFET'TS SOFTWALE P.0UND-OfF TOTAL ^ALLOUANCES
~
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- AfJALYSIS SETP0lili ALTERED GY Tile TOTAL ERROR VALUE 1R A C0i'SERVATIVE DIRECT 10lJ c:
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EQUIPT.1ENT SETPOINT BISTAT.L E EQUIP' DENT SETPOINT A'LTERED
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- CONVERTER-
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ALL ANALYZED EVENTS EVENT SPECIFIC ANALYSES:
ANALYSIS SETPOINT g
ANALYSIS SETPOINT g
TOrAl ANA I
!T E Q U IPt.1E N T 6
ERROR TOTAL TOTAL EQUIPt.1ENT EQUIPMENT ERROR ERROR V__
Y EQUIPMENT y
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> HIGH LINEAR POWER BISTABLE COMPARATOR
> HIGH LOGARITHMIC POWER CEA POSITIONS M
CPC COLD LEG TEMPER ATURE-DIGITAL HOT LEG TEMPERATURE '>
CALCULATOR
REACTOR COOLANT PUMP SPEED DISTABLE COT.* PAR ATOR
> HIGH PRESSURIZER PRESSURE PRESSUnlZER PRESSURE BISTABLE COMPAR ATOR
> LOW PRESSURIZER PRESSURE LOW STE Ar1 GENERATOR STEAM GENERATOR
- D BlSTABLE COMPAR ATOR PRESSURE l'R ESSUllE STEAM GENERATOR BISTABLE COMPARATOR y LOW STEAM GENERATOR LEVEL LEVEL BISTADLE COMPAR ATOR
> HIGH STEAM GENERATOR LEVEL CONTAINMiiNT PRESSURE BISTABLE COMPARATOR
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IIEACTOR Piirh ECTIOT.' SYS TEM lt.'PUI S AND TillP " UNCTIONS G
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Figure CORE PROTECTIOfJ CALCULA10R AS PART OF THE REACTOR PROTLCTION SYSTET.!
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v9 ANALYSIS SETPOINT h
CALCULATED TOTAL EQUIPt.;ENT TECHNICAL ERROR CALCULATED SPECIFICATION ALLOWABLE ALLOWABLE VALUE r.
VALUE CALCULATED PERIODIC TEST ERROR DRIFT ALLOWANCE CALCULATED y
EQU!PMENT SETPOINT TECHNICAL y
SPECIFICATION EQUIPMENT S3TPOINT Figure ROUND OFF EFFECTS ON EQUIP!. ENT f;r.TPCINTS AND ALLO'/.'ABLE VALUES P>
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