ML20135C264

Requests That Proprietary Responses Re Justification of Reduced Flow Meter Measurement Uncertainties Be Withheld (Ref 10CFR2.790)

ML20135C264
Person / Time
Site:	Comanche Peak
Issue date:	08/30/1985
From:	Wiesemann R WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML19269B670	List: ML20135C264 TXX-4546, Forwards Rev 1 to Westinghouse Proprietary & Nonproprietary Responses to Questions Re Improved Thermal Design Procedures & Application for Withholding Proprietary Response. Proprietary Responses Withheld (Ref 10CFR2.790)
References
CAW-85-057, CAW-85-57, NUDOCS 8509110373
Download: ML20135C264 (44)

Text

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Westinghouse Water Reactor Electric Corporation Divisions D eaum30cm I

August 30, 1985 CAW-85-057 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Coomision  !

Washington, D.C. 20555 Attention: Mr. V.S. Noonan, Project Director  !

j NR Project Directorate #5 '

APPLICATION FOR WITHHOLDING PROPRIETARY IMFORMATTN FROM pimr Tc DIsti neJIRE .

I

Subject:

Justification of Reduced Flow Meter Measurement Uncertainties

Reference:

Texas Utilities Generating Company Letter, Counsil to Denton, September - 1985  !

i

Dear Mr. Denton:

The proprietary material for which withholding is being requested in the [

reference letter by Texas Utilites Generating Company is further identified in  :

an affidavit signed by the owner of the proprietary information, Westinghouse  !

Electric Corporation. The affidavit, which accompanies this letter, sets forth i the basis on which the information may be withheld from public disclosure by l the Commission and addresses with specificity the considerations listed in l paragraph (b) (4) of 10CFR Section 2.790 of the Commission's regulations.  !

1he proprietary noterial for which withholding is being required is of the same f technical type as that proprietary material previously autaitted with [

Application for Withholdin6 AW-76-60.  !

Accordingly, this letter authorizes the utilization of the accompnying ,

affidavit by Texas Utilities Generating Company, l Correspondence with respect to the proprietary aspects of the application fcr  !

withholding or the Westinghouse affidavit should reference this letter,  !

CAW-85-057, and should tw addressed to the taidersigned.  !

l Very truly yours, gIkM $ 45 l

- A bba (( (OfIl(kHl($ -

Rotert A. Wiesemann, Manager Regulatory & Legirdative Affairs

/Isv I Enclosure (s) [

cci E. C. Shoemaker, Esq.  ;

Office of the Ezecutive Legal Director, NRC

[

L l ___________ _ _ _ _ _ _ _ _ _ _ _ _ _ .

l PROPRIETARY I FORMATION NOTICE l  :

TRANSM:TTD HDEWITH ARE PROPRIETARY AND/0R NON-PROPRIETARY VERSIONS t DOCUMD75 711RNISHD TO 1HE NRC IN CONNECTION WITH REUEST5 FOR CD PLANT SPECIFIC REVIEW AND APPRWAL.

IN ORCER 10 CONFORM TO THE REUIRDENT5 0F 10CFR2 790 CF THE COP 9CSSI REULATIONS CONCERNING THE PROTECTION OF PROPRIETARY INFORMATIO TO THE NRC, THE INFORMATION WHICH IS PROPRIETARY IN THE PROPRETARY VERSIONS IS '

1 CCNTAIND WITHIN BRACKET 5 AND WHDE THE PROPRIETARY IFORMATION HAS

. ttLETD IN 1ME NON-PROPRIETARY VDSIONS GILY THE BRACKET 5 REMAIN, THE -

i IFORMATICN THAT WAS CONTAIND WITHIN THE BRACKETS IN 1HE PROPR HAV3G BED DEEID. THE JUSTIFICATICN FOR Q.A! MING THE INFORMATION S DESIGNATE AS PROPRETARY IS INDICATE IN SCml VRSIONS SY MEANSI LCTDS (a) THROUGH (g) CONTAIND WITH3 PARENTHE5ES LOCATED AS A EFERSCRIPT !

i IMMEDIATEY POLLCW3G THE BRACKET 5 BCL31NG EACH ITDI 0F INFORM  !

IDENTIFIED A5 PRCPRIETARY OR IN 1HE MARGIN CPPOSITE THESE ECH INFORMA!

LCWD CASE LETTDS REFER 10 THE TTPES OF IWORMATICN WE5TING!

H:LES IN CCNFIDENCE IDnTIFIED IN ECTIONS (4)(11)(a) through (4)(11)(g) 0F THE  !

t AFFICAVIT ACCCMPANTING THIS TRAN3MITTAL PUREANT 1010CFR2 !7 I

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AW-76-60 5

AFFIDAVIT-l .

i COMMONWEALTH OF PENNSYLVANIA:

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. COUNTY OF ALLEGHENY:

l Before me, the undersigned authority, personally appeared '

Robert A. Wiesemann, who, being by me duly sworn according to law, de-  !

poses and says that he is authorized to execute this Affidavit on behalf of W'estinghouse Electric Corporation (" Westinghouse") and that the aver-  :

ments of fact set forth in this Affidavit are true and correct to the  !

best of his knowledge, information, and belief:' f i

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l hl. LLJst/M.!ft Robert A. Wiesc:nEn, Manager Licensing Programs . j

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. Sworn to and subscribed '

before rne this / day

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of f Inrd/d 1976. l l

kUL Y ) Moth < .

Notary Public .,, ..

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smeemseee*4 es .e a 6 g gas .,

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l (1) I am Manager, Lice 1 sing Programs, in the Pressurized Water Reactor *

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1 Systems Division, of Westinghouse Electric Corporation and as such. ,

) ,I have been specifically delegated the function of reviewing the

! proprietary information sought to be withheld from public dis-I

! closure in connection with nuclear power plant licensing or rule-making proceedings, and am authorized to apply for its withholding  !

! bn behalf of the Westinghouse Water Reactor Divisions.

l 1

i j (2), I ari making this Affidavit in conformance with the provisions of ,

l 10 CFR Section 2.790 of the Commission's regulations and in con- (

! junction with the Westinghouse application for withholding ac- l

) companying this Affidavit. f i

! (3) I have personal knowledge of the critoria and procedures utilized

by Westinghousa Huclear Energy Systems in designating infomation as a trade secret, privileged or as confidential com.cretal or l  !

financial information.

.l .  ;

(4) Pursuant to the provisions of paragraph (b)(4) of Section 2.790 l

of the Commission's regulations, the following is furnished for I. consideration by the Commission in determining whether the in-  !

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formation sought to be withheld from public disclosure should be  !

! . withheld. l 4 L i

(i) The information sought to be withheld'from pubile disclosuro is owned and has been held in confidence by Westinghouse.

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AW-7G-60 i

i (ii) The information is of a type customarily held in confidence by <

Westinghouse and not customarily disclosed to the public.  ;

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Westinghouse has a rational basis for determining the types of l information customarily held in confidence by it and, in that j . connection, utilizes a system to determine when and whether to hold certain types of information in confidence. The ap- .

[

plication of that system and the substance of that system i t

constitutes Westinghouse policy and provides the rational l l basis required. ,

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i Under that system, information is held in confidence if it  !

1 falls in one or more of several types', the release of which  !

! might result in the loss of an existing or potential com-I

) / petitivo advantage, as follows:

4 .

(a) The information reveals the distinguishing aspects of a l process (or component, structure, tool, method, etc.)

where prevention of its use by any of Westinghouse's l ,

I competitors without license from Wostinghouse constitutes i

'a competitive economic advantage over other companics.

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(b) It consists of supporting data, including test data, l f^ relative to a process (or component, structure, tool,

!, , [

method, etc.), the application of which data secures a l competitive economic advantage, e.g., by optimitation or j

]

j improved marketability.

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. t (c) Its use by a competitor would reduce his expenditure <

j of resources or improve his competitive position in the  !

design, manufacture, shipment, installation, assurance of quality, or licensing a similar product. j i

(d) It reveals cost or price information, production cap- l acities, budget levels, or commercial strategies of l Westinghouse, its customers or suppliers. i i

It reveals aspects of past, present, or future West-(e) f inghouse or customer funded development plans and pro-grams of potential commercial value to Westinghouso, i i

/ (f) It contains patentable ideas, for which patent pro-taction may be desirable. .

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(g) It is not the property of Westinghouse, but must bo , l treated as proprietary by Westinghouse according to j agreements with the owner, j

[

i There are sound policy reasons behind the Westinghouse  !

sys, tem which include the followingt i

i  !

(a) The use of such inforraation by Uostinghouse gives l Westinghouse a competitive advantage over its com- [

petitors. It is,'therefore, withheld from disclosure  !

to protect the Westinghouse competitivo position.

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AW-76-60 l '

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I i (b) It is information which is marketable in many ways. ,

l The extent to 'which such information is available to competitors diminishes the Westinghouse ability to i sell products and services involving the use of the d

information. ,

l (c) Us by our competitor would put WMtinghouse at a I

competitive disadvantage by reducing his expenditure of resources at our expense.

1 (d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage. If ,

/ competitors acquire components of proprietary infor-mation, any one component may be the key to the entiro ,

' punle. thereby depriving Westinghouse of a competitive advantage.

(e) Unrestricted disclosure would jeopardize the position  ;

.

• of prominence of Westinghouse in the world market. l end thereby give a market advantage to the competition in those countries.

t (f) The Westinghouse capacity to invest corporato assets in research and development depends upon the success  !

.. in obtaining and maintaining a competitivo advantago. 1

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I AW-76-60 i

(iii) The information is being transmitted to the Commission in '

confidence and, under the provisions of 10 CFR Section 2.790, l , it is to be roccived in confidence by the Commission.

1 .

(iv) The information is not available in pubile sources to the l best of our knowledge and belief.

'(v) The proprietary information sought to be withheld in this sub-mittal is that which is appropriately marked in the attach-ment to Westinghouse letter nurr.ber NS-CE-1298. Eicheldinger to Stolz, dated Occcmber 1.1976, concerning information relating to NRC review of WCAP-C5G7-P and WCAP-8568 cntitled, " Improved Thermal Design Procedure." defining the sensitivity of DilB

! ratio to various coro paramotors. The letter and attachment are boing submitted in response to the NRC request at the October 2g,1976 NRC/ Westinghouse meeting.

l This information enables Westinghouse to:

1 (a) Justify the Westinghouse dasign.

l .

(b) Assist its customors to obtain licenses.

1 (c) Hect warranties. ,

(d) Provida greator operational flexibility to customers assuring them of safe and rollable operation. ,

(c) Justify increased power capability or operating nargin I for plants while assuring safe and rollable operation. ,

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AW-76-60 1 -

(f) Optimize reactor design and performance while maintaining <

.a high level of fuel integrity. ,

Further, the information gained from the improved thennal design procedure is of significant commercial value as follows:

(a) Westinghouse uses the information to perform and justify I analyses which are sold to customers.

(b) Westinghouse sells analysis services based upon the ,

experience gained and the methods developed.

Public disclosure of this information concerning design pro- l

/ cedures is likely to cause substantial hann to the competitive position of Westinghouse because competitors could utilize this information to asscss and justify their own designs without commensurate expense. l The parametric analyses performed and their evaluation represent a considerable amount of highly qualified development effort.

This work was contingent upon a design method development pro- , l gram which has been undenlay during the past two years. I Altogether, a substantial amount of money and effort has been  ;

expended by Westinghouse which could only be duplicated by a competitor if he were to invest similar sums of money and pro- l vided he had the appropriate talent available. '

Further the deponent sayeth not.

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r T 4 WESTINGHOUSE PROPRIETARY CLASS 3 Ouestions:

1.

Provide and justify the variances and distributions for input parameters.

2.

Justify that the' nominal conditions used in the analyses bound all permitted modes of plant operation.

3.

Provide a block diagram depicting sensor, processing . equipment, computer, and readout devices for each parameter channel used in the uncertainty analysis.

Within each element of the block diagram identify the accuracy, drif t, range, span, operating limits, and setpoints.

Identify the overall accuracy of each channel transmitter to final output and specify the minimum acceptable accuracy for use with the new procedure.

Also identify the overall accuracy of the final output value and maximum accuracy requirements for each input channel for this final output device.

Resnonse

\

I. INTRODUCTION j ,

Four operating parameter uncertainties are used in the uncertainty an*. lysi the Improved Thermal Design Procedure (ITOP).

These operatir.g parimeters are

! pressurizer pressure, primary coolant temperature (T,,,), reactor power, reactor coolant system flow.

f These parameters are monitore. r on a regular i

basis and several are used for control purposes. The reactor power is

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i monitored by the performance of a secondary side her.c balance (power calorimetric measurement) at least once every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. i

! The RCS flow is i monitored of each cycle.by the performance of a precision flow reasurement at the be

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The RCS loop elbow taps can tNn be normalized against the

' precision measurement and used for monthly s4rvet11ance (with a small incr in total uncertainty) or a precision flow measurement can be performed on same surveillance schedule.

Pressurite.r pressure is a controlled parameter and the uncertainty for the Improved thermal Design Procedure reflects the use of the control system.

T,,, is 4 controlled parameter through the use of j

the temperature input to the Control Rod control system; the uncertainty presented here reflects the use of this control system.

60380:10/112784 la

! Rev. 1 i

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s 1 WESTINGHOUSE PROPRIETARY CLASS 3  !

Since 1978 Westinghouse has been deeply involved with the development of several techniques to treat instrumentation uncertainties, errors, and allowances.

The earlier versions of these techniques have been documented for several plants; one approach uses the methodology outlined in WCAP-8567

" Improved Thermal Design Procedure"O ' ' }

which is based on the conservative assumption that the uncertainties can be described with uniform probability distributions.

The other approach is based on the more realistic assumption that the uncertainties can be described with normal probability distributions.

This assumption is also conservative in that the " tails" of the normal distribution are in reality " chopped" at the extremes of the ran ,

i.e., the ranges for uncertainties are finite and thus, allowing for some probability in excess of the range limits is a conservative assumption . This approach has been used to substantiate the acceptability of the protection system II ,

setpoints for several plants with a Westinghouse NSSS, e.g., D. C. Coo North Anna Unit 1. Salem Unit 2 Sequoyah Unit 1 McGuire Unit 1. V. C. Summer , and Westinghouse believes that the latter approach can be used i for the determination of the instrumentation errors and allow ITDP parameters. The total instrumentation errors presented in this resp are based on this approach.

, II. METHODOLOGY The methodology used to combine the error components for a channel is basically the appropriate statistical combination of those groups of components which are statistically independent, i.e., not interactive.

errors which are not independent Those are combined arithmetica11y to form independent groups, which can then be systesatical1y combined.

~

The statistical combination technique used by Westinghouse is the [  ;

]+8'C l of the instrumentation uncertainties. The instrumentation uncertainties are two sided distributions .

The sum of both sides is equal to the range for that parameter, e.g.,

[ ]+a,c Rack Drif t is typically

, the range for this parameter is [ "]+a,c This technique has been utilized before as noted above and has-been' staff e

endo and various industry standards (8,0,

.L, 6038Q:1D/112784 2a Rev. 1 5 (

s i WESTINGHOUSE PROPRIETARY CLASS 3 i

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The relationship between the error components and the statistical instrumentation error allowance for a channel is defined as follows 1.

For parameter indication in the racks using a DVM;

+a,e Eq. 1 2.

For parameter indication utilizing the plant process computer;

+a,e Eq. 2 3.

For parameters which have control systems;

+a,e Eq. 3 where:

CSA =

Channel Statistical Allowance PMA =

Process Measurement Accuracy PEA =

Primary Element Accuracy SCA =

Sensor Calibration Accuracy SD =

Sensor Drift STE =

Sensor Temperature Effects SPE = I Sensor Pressure Effects RCA =

Rack Calibration Accuracy RD =

Rack Drift RTE =

Rack Temperature Effects 60380:1D/112784 3a Rev. 1

s i 1

WESTINGHOUSE PROPRIETARY CLASS 3 DVM =

Digital Voltmeter Accuracy ID =

Computer Isolator Drift A/D =

Analog to Digital Conversion Accuracy CA =

Controller Accuracy The parameters above are as defined in reference 4 and are based on SAMA standard PMC-20-1973( 0) .

However, for ease in understanding they are paraphrased below:

PMA -

non-instrument related measurement errors, e.g., temperature stratification of a fluid in a pipe, PEA - errors due to metering devices, e.g., elbows, venturis, orifices, SCA -

reference (calibration) accuracy for a sensor / transmitter.

50 -

change in input-output relationship over a period of time at reference conditions for a sensor / transmitter, STE -

change in input-output relationship due to a change in ambient temperature for a sensor / transmitter, SPE -

change in input-output relationship due to a change in static pressure for a Ap cell, RCA -

reference (calibration) accuracy for all rack modules in loop or channel assuming the loop or channel is tuned to this accuracy.

This assumption eliminates any bias that could be set up through calibration of individual modules in the loop or channel.

RD -

change in input-output relationship over a period of time at reference conditions for the rack modules.

RTE -

change in input-output relationship due to a change in ambient temperature for the rack modules, DVM - the measurement accuracy of a digital voltmeter or multimeter on it's most accurate applicable range for the parameter measured, 10

- change in input-output relationship over a period of time at reference conditions for a control / protection signal isolating device, A/D -

- allowance for conversion accuracy of an analog signal to a digital signal for process computer use, CA -

allowance for the accuracy of a controller, not including deadband.

6038Q:10/112784 4a Rev. 1 1 t'

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s i WESTINGHOUSE PROPRIETARY CLASS 3 A more detailed explanation of the Westinghouse methodology noting the interaction of several parameters ic provided in reference 4. '

III.

Instrumentation Uncertainties l

The instrumentation uncertainties will be discussed first for the two parameters which are controlled by automatic systems, Pressurizer pressure, and T,yg (through Rod Control). The uncertainties for both of these parameters are listed on Table 1, Comanche Peak Instrumentation Uncertainties.

1. Pressurizer Pressure Pressurizer pressure is controlled by a system that compares the measured pressure against a reference value. The pressure is measured by a pressure cell connected to the vapor space of the pressurizer.

Allowances are made as indicated on Table 1 for the transmitter and the process racks / controller. As noted, the CSA for this function is [

]+a c with a bias of [

]+a.c which corresponds to a control accuracy of [ ]+"'" with a bias of [ ]***C The accuracy assumed in the ITDP analysis is

[ ]+" with a [ ]+a,c bias. Being a controlled parameter, the nominal value of 2235 psig is reasonable and bounded by ITOP error analysis assumptions, i.e., assuming a normal, two sided distribution for CSA and a 95+% probability distribution for the noted CSA, a equals

[ ]+" with a bias of [

to a = [

]*". This corresponds

]+a,c with a bias of [ ]+a,c ,

2.TAyg T

g is controlled by a system that compares the auctioneered high T from the loops with a reference derived from the First Stage Turbine Impulse Pressure. T,yg is synthesized from N Power and Tc . The highest loop T, g is then used in the controller. Allowances are made as noted on Table 1 for the sensor / transmitters and the process racks / controller. As noted, the CSA for this function is [ ]+" with a bias of [ ]+a,c 60380:10/120484 Sa Rev. 1

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• WESTINGHOUSE PROPRIETARY CLASS 3 which corresponds to an instrumentation accuracy of [ ]**'" with a bias of [ ] "'". Assuming a normal, two sided distribution for CSA and  !

a 95+% probability distribution results in a standard deviation, a =

( )+a,c , .

However, this does not include the controller deadband of i 1.5'F. To determine the controller accuracy the instrumentation accuracy must be combined with the deadband.

Westinghouse has detennined that the probability distribution for the deadband is [

3,+a,c 1

The variance for 'the deadband uncertainty is then:

g

)+a,c and the standard deviation, a = [ ]+a,c, I

Combining statistically the standard deviations for instrumentation and 4 deadband results in a controller standard deviation of:

a, =

(aj2 + '22[.[

] +a.c i o with a bias of [ ]+a.c, i Therefore, the controller uncertainty for a 95+% normal probability distribution is [ )+"'",

with a bias of [ ]+. This is the uncertainty assumed for the ITOP error analysis and reasonably bounds the nominal value corresponding to the full power T gg.

3. Reactor Power i

Generally a plant performs a primary / secondary side heat balance on hours when power is above 15% Rated Thermal Power.

This heat balance is used to verify that the plant is operating within the limits of the Operating License and to adjust the Power Range Neutron Flux and 16 N power channels when the difference between the NIS and the heat balance is greater than required by the plant Technical Specifications.

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WESTINGHOUSE PROPRIETARY CLASS 3 Assuming that the primary and secondary sides are in equilibrium; the core power is determined by summing the thennal output of the steam generators.

correcting the total secondary power for steam generator blowdown (if not secured), subtracting the RCP heat addition, adding the primary side system j

losses, and dividing by the core rated 8tu/hr at full power. The equation for l this calculation is:

N RP = I [QSG ~ 003 *0 L 100 Eq. 4 1

where; RP =

Core power ( 5 RTP)

N =

Number of primary side loops Q3g =

Steam Generator thermal output (Btu /hr) 0 =

P RCP heat adder (8tu/hr)

Q =

Primary system net heat losses (Btu /hr)

{ H =

Core rated 8tu/hr at full power.

o For the purposes of this uncertainty analysis (and based on H noted above) it is assumed that the plant is at 100% RTP when the measurement is taken. Measurements performed at lower power levels will result in different uncertainty values. However, operation at lower power levels results in increased margin to ON8 far in excess of any margin losses due to increased measurement uncertainty.

The thermal output of the steam generator is determined by a calorimetric measurement defined as:

I

= i Q3g (h3 -h)W f f Eq. 5 1

6038Q:10/112784 Ba

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WESTINGHOUSE PROPRIETARY CLASS 3 where; h, =

Steam enthalpy (Btu /lb) h =

f Feedwater enthalpy (8tu/lb)

W =

f Feedwater flow (lb/hr).

The steam enthalpy is based on the measurement of steam generator outlet steam pressure, assuming saturated conditions. The feedwater enthalpy is based on the measurement of feedwater temperature and feedwater pressure. The feedwater flow is determined by multiple measurements and a calculation based on the following:

W =

f (K)(F,) ((pf)(Ap)}I# Eq. 6 where:

K =

Feedwater venturi flow coefficient F, =

Feedwater venturi correction for thermal expansion pf =

Feedwater density (lb/ft )

Ap =

Feedwater venturi pressure drop (inches H O).

2 The feedwater venturi flow coefficient is the product of a number of constants including as-built dimensions of the venturi and calibration tests performed by the vendor.

The thermal expansion correction is based on the coefficient of expansion of the venturi material and the difference between feedwater temperature and calibration temperature. Feedwater density is based on the measurement of feedwater temperature and feedwater pressure. The venturi pressure drop is obtained from the output of the differential pressure cell connected to the venturi.

The RCP heat adder is determined by calculation, based on the best estimates of coolant flow, pump head, and pump hydraulic efficiency.

The primary system net heat losses are determined by calculatten, considering '

the following system heat inputs and beat losses:

6038Q:lD/112784 9a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 Charging flow Letdown flow Seal injection flow RCP therinal barrier cooler heat removal Pressurizer spray flow Pressurizer surge line flow Component insulation heat losses Component support heat losses CRDM heat losses A single calculated sum for full power operation is used for these losses / heat inputs.

The core power measurement is based on the following plant measurements:

Steamline pressure (P )

3 Feedwater temperature (Tg )

Feedwater pressure (Pg )

Feedwater venturi differential pressure (Ap)

Steam generator blowdown (if not secured) )

and on the following calculated values:

Feedwater venturi flow coefficient (K)

Feedwater venturi thermal expansion correction (F,)

Feedwater density (pg )

Feedwater enthalpy (hg )

Steam enthalpy (h3 )

Moisture carryover (impacts h )

3 Primary system net heat losses (Q )

t RCP heat adder (Qp )

These measurements and calculations are presented schematically on Figure 1 .

Starting off with the Equation 6 parameters, the detailed derivation of the measurement errors is noted below.

6038Q:10/ll2784 10a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 Feedwater Flow Each of the feedwater venturis is calibrated by the vendor in a hydraulic laboratory under controlled conditions to an accuracy of [ ]+"' '" of span.

The calibration data which substantiate 3 this accuracy is provided for all of the plant venturis by the respective vendors. An additional uncertainty factor of ( )+"'C is included for installation effects, resulting in an overall flow coefficient (K) uncertainty of [ ]+".

Since steam generator thermal output is proportioral to feedwater flow, the flow coefficient uncertainty is expressed as [ ]***C power.

The uncertainty applied to the feedwater venturi thermal expansion correction (F,) is based on the uncertainties of the measured feedwater temperature and the coefficient of thermal expansion for the venturi material, usually 304 stainless steel. For this material, a change of 2*F in the feedwater temperature range changes F, by [ ]+a,b c and the steam generator thermal output by the same amount. For this derivation, an uncertainty of

[ ]+a.c in feedwater temperature was used (see Table 1) which results in a total uncertainty in F, and steam generator output of [ ]+"'".

Based on data introduced into the ASME code, the uncertainty in F, for 304

. stainless steel is 15 percent. This results in an additional uncertainty of

[ ]+"'" in feedwater flow. A conservative value of [

is used in this analysis.

]****

Using the ASME Steam Tables (1967) for compressed water, the effect of a

[ ]+a,c error in feedwater temperature on the (p ) # is g

[ ]+a c in steam generator thermal output. An error of

[ ]+a.c in feedwater pressure, see Table 1, results in an uncertainty in (pt)l/2 of : [ ]+a,c in steam generator thernal output.

Table 1 provides a listing of the instrumentation errors for feedwater Ap assuming display on the process computer. ,

The electronics errors are in '

percent Ap span and must be translated into percent feedwater flow at full power conditions. This is accomplished by multiplying the error in percent  !

Ap span by the conversion factor noted below:

6038Q:10/120484 lla Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 1

I) I 2 span of feedwater flow 100 transmitter in 5 of nominal flow)

For a feedwater flow transmitter span of ( ]**** nominal flow, the conversion factor is ( 3*"'" (which is the value used for this analysis).

Feedwater Enthalov The next major error component is the feedwater enthalpy used in Equation 5 .

For this parameter the major contributor to the error a the uncertainty in the feedwater temperature.

Table 1 provides the detatied error breakdown for this temperature measurement assuming indication on the process computer .

Statistically summing these errors (utilizing Eq. 2) results in a total temperature error of (

]+8'" span. Using a span of 500*F results in a temperature error of ( ).+a,c Using the ASME steam tables (1967) for compressed water, the effect of a (

]+a.c error in feedwater temperature on the feedwater enthalpy (hr) is ~ [ ]+a c in steam generator therral output. Using a [

pressure results in ~ [ ]+a c error in feedwater

)+a,c effect in hr and steam generator thermal output.

},tfan Enthalov The steam enthalpy has two contributors to the calorimetric error, steamline pressure and the moisture content.

For steamline pressure the errors are as noted on Table 1, assuming display on the process computer.

This results in a total instrumentation error (utilizing Eq. 2) of ( )**'" span with a bias of ( )+a,c .

Based on a 1300 psig span this equals

( )+a,c with a bias value of (

).+a c The bias value is correctly carried through the calculation to its conclusion. Using the ASME Steam Tables (1967) for saturated water and steam, the effect of a (

]+"'"

error in steamline pressure on the steam enthalpy (h,) is

~[ ]+a,c in steam generator thermal output.

The bias value of ( ]+a c has an effect equivalent to ( a ]+a.c in steam generator thermal output.

60380:10/120484 12a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 The major contributor to h, uncertainty is moisture content. The nominal or best estimate performance level is assumed to be [ ]" '*, which is the design limit to protect the high pressure turbine. The most conservative i

assumption that can be made in regards to maximizing steam generator thermal '

)

output is a steam moisture content of zero. This conservatism is introduced by assigning an uncertainty of [ ]+ to the moisture content, which '

j is equivalent through enthalpy change to [ ]+ of thermal output.

i looD Power i  !

The loop power uncertainty is obtained by statistically combining all of the j

error components noted for the steam generator thermal output (03g) in terms i

} of loop power.

Within each loop these components are independent effects (or formed into independent quantities) since they are independent measurements.

l The feedwater temperature and pressure uncertainties are common to several of I

the error components, thus they are formed into independent quantities prior to the statistical combination. The bias for steamline pressure is  !

appropriately treated as noted on Table 2.

I Another effect which tends to be dependent, affecting all loops, is the accumulation of crud on the feedwater venturis, which can effect the Ap for

}

a specified flow. Although it is conceivable that the crud accumulation could i

affect the static pressure distribution at the venturi throat pressure tap in f a manner that would result in a higher flow for a specified Ap, the

} reduction in throat area resulting in a lower flow at the specified Ap is

] the stronger effect. All reported cases of venturi fouling have been  !

associated with a significant loss in electrical output, indicating that the

{

actual thermal power has been below the measured power rather than above it.

Losses in net power generation which have been correlated with venturi fouling I have occurred in about half of the Westinghouse pressurized water reactors operating in the United States. These power losses have been generally in the range of two to three percent.

Power losses have also occurred in at least

three, and possibly five Westinghouse plants operating abroad. In no case has i venturi fouling been reported which resulted in a non-conservative feedwater flow measurement. Because the venturi crud formations have resulted in a conservative, reduced power condition, no uncertainty has been included in the i analysis of power measurement error for this phenomenon.

l j 60380:10/120484 1 134 Rev. 1  !

i I i

O

• WESTINGHOUSE PROPRIETARY CLASS 3 The net pump heat uncertainty is derived in the following manner. The primary system net heat losses and pump heat adder for a four loop plant are summarized as follows:

Systems heat losses

- 2.0 mt Component conduction and convection losses - 1.4 Pump heat adder

+18. 0 Net Heat input to RCS

+14.6 Wt i

The uncertainties for these quantities are as follows: The uncertair.ty on

{

system heat losses, which are essentially all due to charging and letdown flows, has been estimated to be ( )*"'" of the calculated value. Since direct measurements are not possible, the uncertainty on component conductio and convection losses has been assumed to be value.

[ of the calculated

]+8

Reactor coolant pump hydraulics are known to a relatively high

• confidence level, supported by the system hydraulics tests performed at Prairie Island 11 and by input power measurements from several plants, so th uncertainty for the pump heat adder is estimated to be [ ]+a c of the best estimate value.

Considering these parameters as one quantity which is designated the net pump heat uncertainty, the combined uncertainties are mu

) less than [ ]+ of the total, which is equivalent to [

of core power. ]+8'C The Total Loop Power uncertainty (noted in Table 2 as % [ ]+a,c with a bias of [

! ]+a.c) is the statistical sum of the calorimetric i

uncertainties for a single loop. The Total Secondary Power uncertainty is the statistical combination of the Loop Power uncertainty and the number of primary side loops in the plant. As noted in Table 2, the Secondary Power 4

uncertainty for Comanche Peak is : 12.0% with a bias of 0.04% RTP.

6038Q:1D/120484 14a Rev. 1

. o WESTINGHOUSE PROPRIETARY CLASS 3 The Total Secondary Power uncertainty is less than or equal to the historically used value of 1 2% power. For ITDP, credit is taken for the increased knowledge of reactor power and the value noted above is used in the ITDP error analysis, i.e., the standard deviation for reactor power, at the 95+% probability level is,

'"E ]**'" with a bias of ( )+a.c, s

t

[

i l

l 6038Q:10/120484 15a 1 Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 FIGURE 1 POWER CALORIMETRIC SCHEMATIC P

s

}( P f l { T }l AP )

f

,, N h, h f of F, K

}

W C f ,_

O - measured

/

Qg g

D - calculated l U i Other Loops  !

I l

+

V O

L P I

Core Power I

i 6038Q:10/112784 16a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 TABLE 2 SECONDARY POWER CALORIMETRIC MEASUREMENT UNCERTA Component Instrument Error Power Uncertainty Feedwater Flow -

Venturi, K - +a,c Thermal Expansion Coefficient Temperature Material Density Temperature Pressure Ap Feedwater Er.thalpy Temperature Pressure Steam Enthalpy Pressure Random Bias Moisture Carryover Net Pump Heat Addition Uncertainty

+a,e l

i i

~

l Loop Power Uncertainty = {I(e) }I 2 =

g

)+a,c

+a,c

. Total Secondary Power Uncertainty - ({I(e)2}/4)l/2 =

60380:10/112784 17a Rev. 1

_ - - . -_ = _ _ _ - - . - _ _ - - -

WESTINGHOUSE PROPRIETARY CLASS 3

4. _RCS FLOW RCS flow is monitored by the performance of a precision flow measurement (through the use of the N-16 Transit Time Flow Meter and a secondary side power measurement) at the beginning of each cycle. The RCS cold leg elbow taps can then be normalized against the precision measurement and used for monthly surveillance (with a small increase in total uncertainty). The analysis presented in this report documents both measurements, i.e., the precision measurement and the elbow tap normalization uncertainties.It is assumed for i.his error analysis that the precision flow measurement is performed at the beginning of a cycle (thus eliminating allowances for feedwater venturi fouling) and within the calibration period (90 days) of the i

measurement instrumentation (thus reducing drift effects to the values noted on Table 1).

l

)

The flow measurement of the cold leg volumetric flow is performed b I the hot leg volumetric flow very accurately with the N-16 Transit Time Flow Meter (TTFM), determining the hot leg specific volume by the performanc precision secondary side power calorimetric (to infer T ) and then  ;

H calculating the cold leg volumetric flow so the cold leg elbow taps can be

. normalized.

The second two steps are necessary because the plant does not i

have RTO bypass loops with main coolant pipe scoops (thus, the T H

measurement is subject to large streaming errors) and because the safety analyses use cold leg volumetric flow as an initial condition parameter.

The TTFM is a set of detectors placed on each of the primary side hot that measures the time it takes for an N-16 noise spike to traverse a known distance.

This allows a calculation of the hot leg coolant flow velocity and given the cross-sectional area of the hot leg piping, the volumetric flow rate.

i This flow rate can be measured quite accurately (

an individual loop basis. ]+a c on WCAP-9172 (Proprietary) describes the measurement technique in more detail I "I.

60380:10/112984 18a Rev. 1

{

WESTINGHOUSE PROPRIETARY CLASS 3 One of the reasons for ineasuring RCS f1w accurately is to normalize the cold l 1eg elbw tips, which measure the cold les volumetric f1w rate. Normally a precision f1w calorimetric is performed to determine the f1w rate. This  ;

{ involves performing a secondary side power calorimetric and measuring the '

primary side enthalpy rise (via TH and T ). Hwever, as noted, this plant i C i does not have scoops and R10 bypass loops to measure primary side temperatures. Instead it has RTDs in thermowells. This is reasonable for T  !

{

' where the coolant is well mixed after passing through the RCPs, but T C indication may be in error due to streaming in the hot leg and the small H  !'

cross-section seen by the t.iermowell. Therefore, it is not advisable to use measuredHT in the determittation of the RCS flow. Instead, an iterative '

approach is used to infer T H from measured secondary side loop power, T '

! C and hot leg volumetric flod. The uncertainty analysis that follows is divided j

{

i into four parts; TTFM, Power Calorimetric, Not Leg to Cold Leg Conversion, and Elbw Tap Normalization.

l A. Transit Time Flow Meter ,

j The TTFM uncertainties are discussed in detail in Reference ll, however, to I sunparize, the major error components are due to detector placement and l

• difference in fluid velocities as seen by the detector /collimator pairs. The refined uncertainties and the total system uncertainty is provided in Table 3.

1 1 - i

' =

+a,c i J  ;

} {

1  !

1 .

l  !

I  !

I i l l i

i This is reflected in the calculations of Table Sa.

i i i

I -

j 60300:10/120444 Iga Rev. 1 i

I  !

WESTINGHOUSE PROPRIETARY CLASS 3 TABLE 3 i

TRANSIT TIME FLOWMETER UNCERTAINTIES Component UncertaintvII)

Fluid Flow

.+ a,c Radial Velocity Profile .

Azimuthal Velocity Profile Cross Flow Mechanical Detector Spacing and Detector /Collimator Angle Pipe Internal Cross Sectional Area Data Collection Statistics Data Reduction System Timing Phase Shift

.[

)+a.c ,

~

Total uncertainty for TTFM = '

(1) Based on further refinement of data presented in WCAP-9172(III 60380: 10/112784 20s Rey, 1

WESTINGHOUSE PROPRIETARY CLASS 3 A meeting was held on October 11, 1984 between representatives of Texas Utilities Generating Company, Westinghouse, and the NRC to discuss the uncertainties noted in Table 3.

As a result of these discussions it was agreed that the total TTFM uncertainty would be increased to (

on a single loop basis. )+8'"

This increase was deemed necessary by the staff to cover perceived uncertainties in the Azimuthal Velocity Profile.

The result of this requirement is the addition of what is called an 'NRC conservatism factor" of ( )***" to the listing of Table 3.

The uncertainties then calculated for the TTFM are:

~

+

.ac These values are reflected in the calculations of Table 5b.

8. Power Calorimetric The secondary side power calorimetric is perforned in the same manner as described in Section 111.3, except with more precision (via the use of special test instrumentation) and the gathering of multiple data sets, i.e., data is gathered at approximately five minute intervals over a one hour time period.

The sensitivities noted in Section !!!.3 are also applicable to this calculation.

The specific instrument uncertainties used in this calculation for the calorimetric are noted in Table 5 and are derived from the precision uncertainties noted in Table 1.

C.

Not tea to Cold Leo Conversion When a heat balance is performed on a plant in equilibrium, power is defined as:

Q = m Ah Eq. T l

)

60380: 10/112784 21a Rev. 1 l

WESTINGHOUSE PROPRIETARY CLASS 3 l where; 1

9 = secondary side calorimetric power (8tu/ min) m = primary side mass flow rate (lb ,/ min)

Ah = primary side enthalpy rise (8tu/lb,)

Since the RCS is a closed system, the hot leg mass flow must equal the cold leg mass flow, or:

m = (Wy/vg) = (We /ve )

Eq. 8 where; W =

H hot leg volumetric flow rate (ft / min) v =

3 H

=

hot leg coolant specific volume ( 1/lb,)

W, cold leg volumetric flow rate (ft / min) v =

3 c

cold leg coolant specific volume (ft /lb,)

Therefore, it can be easily seen that the cold leg volumetric flow is the

. ratio of the specific volumes, times the hot leg volumetric flow:

We"Wg (vg/vg )

Eq. 9 The plant can measure the following for equation 9:

WH by use of the TTFM, vg by measurement of T, and Pressurizer Pressure, v

H by measurement of Pressurizer Pressure, i

A starting point for T H can be the measured value using the hot leg RTD, however there is still the streaming concern.

Instead T H is inferred by the use of secondary side calorimetric power. g T . and hot leg flow, i.e., an iteration is performed by which the power determined by the secondary s calorimetric is compared against the power predicted for an assumed The T.

predicted power is defined as: H 1

60380:10/112984 22a Rev. 1

o .

WESTINGHOUSE PROPRIETARY CLASS 3 q=Wg (hH - hg )/vH

• where; W = 3 H

h =

hot les volumetric flow (ft / min)

N hot leg onthalpy f(Tg . P) h, =

cold les enthalpy f(Tg . P) v *

• H 'E'" "' *

( H' The predicted versus actual power are compared and iterated untti a maximum convergence error is reached.

Table 1 notes the uncertainty for the measurement of Pressurizer Pressure and T.

g Table 4 provides the sensitivity of vg , Tg noted parameters. and v, to the Using the results noted in Tables 1, 3, and 4. Table 5a lists the various components of the flow measurement uncertainty for cold leg volumetric flow calculated by equation g.

As can be seen on Table 5a several measurements are used twice, thus there are some dependent offacts. The equation used to

• determine the loop flow measurement uncertainty is:

+a,c UNC W =

g (Eq. 11) where: -

P = \

yg Pressurizer Pressure for v c F,g =

Pressurizer Pressure for og

=

Tc ,g Tc for vc

~

TeVH

• Fg =

TTFM for WH FM,g =

TTFM for vH LP =

Loop Calorimetric Power IC =

Iterstion Convergence Limit i

60380:10/120484 23a Rev. 1 I

WESTINGN0USE PROPRIETARY CLASS 3 Substituting the values of Table 54 into equation 11. UNC W 3+a.C, C*C The uncertainty for total system flow for a four loop plant is defined as:

T UNC We = +a.c

.(Eq. 12) where:

+a.c

~

Substituting the values of Table $a into equat16n 12. T UNC W e =[

)+a.C ,

The above noted values for UNC W

. e and T UNC gW are based on use of the Westinghouse values for the TTFM uncertainty and do not include the 'NRC conservatism factor'. Table $b notes the changed values for FM g and FM that would result from the use of the conservatism factor. Substituting these values into equations 11 and 12 result in the following flow uncertainties:

~

UNC W g

+a.c T UNC Wg

~

b.

Hermalized Elbow Taos for RCS Flow Measurement _

Based on the results of Equation 12, in order for a plant to assure operation within the analysis assumptions a precision RCS flow measurement would have 6038Q:10/112784 24a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 be performed once every 31 EFPO. However, this is an involved procedure which requires considerable staff and setup time. Therefore it is expected that the plant will perforr one flow measurement at the beginning of the cycle and normalize the loop elbow taps. This allows the operator to quickly determine if there has been a significant reduction in loop flow on a shift basis and to avoid a long monthly procedure. The elbow taps are forced to read 1.0 in the process racks after performance of the precision flow measurement, thus, the elbow tap and its Ap cell are seeing normal operating conditions at the time of calibration /nornalization and 1.0 corresponds to the measured loop flow at the time of the measurement.

For monthly surveillance to assure plant operation consistent with the analysis assumptions, two means of determining the RCS flow are available.

One, to read the loop flows from the process computer, and two, to measure the output of the elbow tap Ap cells in the process racks with a DVM. The uncertainty for the use of the process computer and its convolution with the precision flow measurement uncertainty is presented as follows.

l l

l 60380:10/120484 25a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 TABLE 4 DH. TH. Vc SEN$1TIVITY Component sensitivitu

. +a c

'M Pressurizer Pressure T

H

\

Ty Loop Power Tg W

H Convergence

'c Pressurizer Pressure Tg 1 O

l.

i

{

l i

l I

60380:10/112784 26a Rev. 1

f 1

WESTINGHOUSE PROPRIETARY CLASS 3 FIGURE 2 PREC1310N RC5 MEASUREMENT SCHEMTIC P P f T Ap f

\

U h, h f f f F, K E

= w, i'

z 03g -e 4 . --

p h p T g

\ .

JL

} z T h "c U

N --

i' "c _

O evasured i

O esiculated

{ j other loops U

Total RCS Flow 6038Q:10/112184 27a Rey, 1

o WESTINGHOUSE PROPRIETARY CLASS 3 TABLE Sa PREclSION RCS FLOW MEASUREMENT UNCERTAINTIES (Without NRC conservatism factor in TTFM error)

Component Instrument Error Flow Uncertaintv Secondary Side Power Calorimetric '

l Feedwater Flow *

~ +"'"

Venturi, K Thermal Expansion Coefficient Temperature Material Density Temperature Pressure 4p Feedwater Enthalpy I

Temperature >

Pressure Steam Enthalpy Pressure Motsture Carryover Net Pump Heat Addition Uncertainty l Primary Side Flow ,

"c Temperature (Tc )

Pressure '

l Random Blas ,

I 6038Q:10/112784 2sa Rey, 1  !

WESTINGHOUSE PROPRIETARY CLASS 3 TABLE Sa (Continued)

PRECISION RCS FLOW MEASUREMENT UNCERTAINTIES Component Instrument Error Flow Uncertainty

- +a c '

'N Pressure Random Bias Temperature Loop Power Tg W Random H

Systematic T I eration Con m gence H

TTFM Random Systematic

"'+a c i

4 Precision Secondary Side Loop Power Calorimetric Uncertainty =

(I(e)2)1/2 , g )+a c Loop Flow Uncertainty =

(I(e) ) =[ )+a.c Total RCS Flow Uncertainty =

((I(e) }/4)1 2 , g )+a,c 60380:10/120484 29a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 TABLE Sb PRECISION RCS FLOW MEASUREMENT UNCERTAINTIES (With NRC conservatism factor in TTFM error)

Component Instrument Error Elow Uncertainty Secondary Side Power Calorimetric Same as Table Sa.

Primary Side Flow v

c -

- +a,c Temperature (T )

c Pressure Random Bias "H

Pressure Random

, Bias Temperature l Loop' Power c

l W Random H

Systematic T

H Iteration Convergence TTFM 4

Random Systematic 6038Q:10/120484 30a Rev. 1

.

• WESTINGHOUSE PROPRIETARY CLASS 3 l

TABLE Sb (Continued)

.+a,c Loop Flow Uncertainty =

i gg (,)2)1/2 , g

)+a,c Total RCS flow Uncertainty =

({I (e) }/4)1/2 , ( )+a,c l

1 l

60380:10/120484 31a Rev. 1

t WESTINGHOUSE PROPRIETARY CLASS 3 Assuming that only one elbow tap per loop is available to the process computer and using the uncertainties for the elbow tap noted in Table 1 results in the following elbow tap measurement uncertainty:

5 flow  % flow p

+a,e "

~ +a,c PEA RTE SCA RD SPE ID STE A/D SD

• ~

Readout Where:

Readout

= Allowance for variability of process signal, and all other parameters are as noted for Equation 2.

The Ap span of Table 1 is converted to flow on the basis the instrument span is [ ]+a.c The uncertainty for this flow measurement is:

UNC ET =

- +a,c Eq. 13 Using the values noted above, for one loop UNC ET = [t 1.53% flow)+a.c . The system flow measurement uncertainty for a four loop plant is defined as: 1 T UNC ET = UNC ET/(4)1/2

~[ ]+a,c I Eq. 14 If the plant process computer is inoperable at the time of required surveillance, readings can be taken in the process racks with a DVM. The accuracy of this measurement is equal to or better than the process computer measurement.

It is therefore conservative to use the process computer uncertainty for this analysis.

l 6038Q:10/ll2984 32a Rev. 1

_ _ _ _ _ _ . - - ,. - -- - -- -^~ ~

a

• WESTINGHOUSE PROPRIETARY CLASS 3 When the elbow taps are normalized against the precision flow measurement, the combined uncertainty is defined as:

+a,c UNC FM = l Eq. 15 l For use in the ITDP calculations, UNC FM is calculated using T UNC W based g

on the Westinghouse TTFM uncertainties without the NRC conservatism factor.

In this instance, UNC FM = [

]+"'". The standard deviation used in the ITOP calculation is then:

o=[ 3+a,c For the Unit i flow versus FAH trade-off Technical Specification, UNC FM is calculated using T UNC W based on use of the NRC conservatism factor.

In this instance, UNC FM = [ ]+a,c, or ~ 1.8%

flow.

The flow measurement uncertainty used this value in the generation of Figure 3.2-3 (in the Comanche Peak Technical Specifications).

As noted earlier in this document Westinghouse assumes no errors due to feedwater venturi fouling. When performing an RCS flow calorimetric this assumption requires some effort on the part of the plant staff to either verify there are no fouling characteristics exhibited, or inspect the venturis (and clean, if necessary), or determine the magnitude of the fouling effects because the flow calorimetric is very sensitive to fouling effects, i.e., a 1%

fouling effect impacts the flow calorimetric by 1%. However, for Comanche Peak this is not the case. The secondary side power calorimetric is used only

' in the determination of a value for HT . Therefore, the sensitivity to venturi fouling is considerably reduced, i.e., a 1% fouling effect impacts the flow measurement uncertainty for the cold leg volumetric flow only by

[ 3+"'" (and does not impact the hot leg volumetric flow measurement at all). Thus, the need for elaborate or comprehensive means of detecting venturi fouling at the 0.1 to 0.2% flow range are unnecessary. Use of normal plant instrument and practices should be more than sufficient to ensure the detection of fouling at levels low enough to make a fouling allowance for Figure 3.2-3 unnecessary.

6038Q:10/120484 33a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 In summary, the instrument uncertainties determined in this document are:

Pressurizer Pressure -

-&a c T,yg Power RCS Flow without NRC conservatism factor (ITOP)

RCS Flow with NRC conservatism factor (Tech Spec) 6038Q:10/112784 34a Rev. 1

WESTINGHOUSE PROPRIETARY CLASS 3 REFERENCES 1.

Westinghouse letter NS-CE-1583, C. Eiche1dinger to J. F. Stolz, NRC, dated 10/25/77.

2.

Westinghouse letter NS-PLC-5111. T. M. Anderson to E. Case NRC, dated 5/30/78.

3.

Westinghouse letter NS-TMA-1837. T. M. Anderson to S. Varga, NRC, dated 6/23/78.

4.

Westinghouse letter NS-TMA-1835. T. M. Anderson to E. Case, NRC, dated 6/22/78.

5.

NRC letter, S. A. Varga to J. Dolan, Indiana and Michigan Electric Company, dated 2/12/81.

6.

NUREG-0717 Supplement No. 4, Safety E*.aluation Report related to the operation of Virgil C. Summer Nuclear Station Unit No.1, Docket 50-395, August, 1982.

7.

NRC proposed Regulatory Guide 1.105 Rev. 2. " Instrument Setpoints", dated 11/83.

8. ANSI /ANS Standard 58.4-1979, ' Criteria for Technical Specifications for Nuclear Power Stations".

9.

ISA Standard $67.04,1982, "Setpoints for Nuclear Safety-Related Instrumentation used in Nuclear Power Plants",

i

10. Scientific Apparatus Manufacturers Association, Standard PMC-20-1-1973,

" Process Measurement and Control Terminology".

11. Graham, K. F., Forker, J. M.,

"An N-16 Transit Time Flow Measurement System (TTFM) Description and Performance," WCAP-9172 (Proprietary),

WCAP-9173 (Non-Proprietary), February 1978.

60380:10/112784 35a Rev. I l

!