ML20100A875

Requests Withholding of Proprietary Response to NRC Request for Addl Info Re RCS Flow Measurement Uncertainty (Ref 10CFR2.790)

ML20100A875
Person / Time
Site:	Seabrook
Issue date:	11/13/1984
From:	Wiesemann R WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML19269A808	List: ML20100A856 ML20100A875
References
CAW-84-84, NUDOCS 8412040116
Download: ML20100A875 (35)

Text

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j NuclearTechnologyDivision Westinghouse Water Reactor Electric Corporation Divisions 80, 333 PittsburghPennsylvania15230 November 13, 1984 CAW-84-84 Mr. Harold Denton, Director Office of Nuclear Reactor Regulation '

Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.:C. 20555 .

APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC oISCLOSURE

SUBJECT:

RCS Flow Measurement Uncertainty REF: Public Service New Hampshire Letter, DeVincentis to Denton, dated November 1984

Dear Mr. Denton:

The proprietary material for which withholding is being requested .is of the same technical type as that proprietary material previously submitted by Westinghouse concerning Reactor Protection System / Engineered Safety Features Actuation System Satpoint Methodology. The previous application for withholding, AW-76-60, was accompanied by an affidavit signed by the owner of the proprietary information, Westinghouse Electric Corporation.

s Further, the affidavit submitted to justify the previous material was approved ,

by the Commission on April 17, 1978, and is equally applicable to the subject material.

Accordingly, it is respectfully requested that the subject information which is proprietary to Westinghouse and which is further identified in the affidavit be withheld from public disclosure in 'accordance with 10CFR Section 2.790 of the Commission's regulations.

Correspondence with respect to the proprietary aspects of the application for '

withholding or the Westinghouse affidavit should reference CAW-84-84 and should be addressed to the undersigned. .,

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o ert A. Wiesemann, Manager

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8efore me, the, undersigned authority, personally appeared Robert. A. Wiesemann, who, being by me duly sworn according to law, de-i poses and says that he is authorized to execute 'this Affidavit on behalf of Westinghouse Electric Corporation (*'Jestinghouse") and that the aver-monts of fact set forth in this Affidavit are true and correct to the best of his knowledge, inforzation, and belief:' -

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- - Robert A. Wiesemann, Manager

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Licensing Programs Sworn to and subscribed before,,asthis8 day of M 4 M .

1976.

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' - 2- AW-76-60 (1) I am Manager, .Ucensing Programs, in the Pressurized Water Reactor Systans Division, of WesItinghouse Electric Corporation and as such.

I have been specifically delegated the funcdon of reviewing the '

proprietary information sought to be withheld from public dis-closure in~ connection with nuclear power plant ifconsing or rule-i making proceedings, and as autherfied -

to apply for its withholding on behalf of the Westinghouse Water Reactor Divisions.

(2) I am making this Affidavit in conformance with the provisions of 10 CFR 5ection 2.790.of the Caserission's regulatiens and in con-junedon with the Wastinghause app 11 cation for withholding ac-companying this Affidavit. .

i (3) I have personal knowledge of the criteria and procedures utilized

- by Westinghouse Nuclear Energr5ystans in designating informadon '

as a trade secret, privileged,or as confidential cosmarcial or -

- ' financial t'nfansation. ,

(4) Pursuant to the provisions of paragraph (b)(4) of Section-2.790 of the Commission's regulations, the following is furnished for .

consideradon by the Commission in determining whether the in-formation sought to be withheld from public disclosure should be withhald. -

.. (1) The information sought to be withheld'from puhtic disclosure is owned and has been. held in confidence by Westinghouse.

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AW-76-40 (ii) The infor=ation is' of a type custosaM1y held in c=nfidence by Westinghouse and not custosarily disclosed to the public.

~ ifestinghousa has a* rational basis for determining the types of information customaM1y held in confidence by it and, in that

. connection, utilizms a system to determine den and dether to hold certain types of information in confidence. The ap-plication of that system and the sestance of that system constitutes Westinghousa polig and provides the rational basis required.  ?

Under that system, information is held in confidence if it l

falls in one or more of. several types', the release of dich

' might result in the loss of an existing or potential com-petitive advantage, as follows: , , . ,

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(a) The infonnation reveals the ' distinguishing aspects of a *

. process (or component, structure, tool, method, ute.)- ,

,dare prevention of its 'use by any of Westinghouse's

, competitors without licansa from Westinghousa constitutes a competitive economic advantage over other companies.

(b) It consists of supporting data, including test data, '

relative to a process '(or component, structure, tool, enthod, etc.), the appif cation of dich data secures a comper:tive economic advantage, e.g., by optimization or improved sartetatility.

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AW-75-60 (c) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufheture, shipment, installation, assurance .

of quality, or licensing a similar product.

(d) It reveals cost or pricg*1nfimadon, production cap-acities, budget levels, or commerdal strategies of Westinghouse, its customers or soppliers.

(e) It reveals aspects of past, present, or future West ,

inghouse or customer funded development plans and pro-grams of potantial cosmarcial value to Westinghouse. .

t (f) It contains patentable ideas, for which patent pro .

taction may be desirEble. , , ,

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- (g) It is not the prophrty of Westinghouse, but must be treated as proprietary by Westinghouse according to ,

agreements with the owner.

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There are sound policy reasons behind the Westinghouse system which include the following: ,

(a) The use of such infomation by Westinghouse gives

- Westinghouse a competitive advantage over its ccm- ,

petitors. It is, therefore, withheld from disclosure

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- to protect the Westinghouse compedtive position. .

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, (b) It is ,information which is marke1iable in many ways.

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The extent to 'which such information is available to competitors diminishes the Westinghouse ability to . '

- - se111 products and services involving tse use of the information.

..t Use by our competitor wo'uld put Westinghouse at a (c) competitive disadvantage by reducing his expenditure of resources at our expense.

(d) Each component of proprietary irformation 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 say be the key to the entire ,

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puzzle thereby depriving Westinghouse of a competitive *

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advantage. -

t(a) Unrestrictad disclosure would. jeopardize the p,osition ,

' I of prominence of Westinghouse in the world market, i

and thereby give a market advantage to the competition in those countries.

I i (f) The' Westinghouse capacity to invest c rporate assets in research and development depends upon the success in obtaining and mainuining a competitive advantage.

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- AW-78-40 (iii) The infomation is being transmitted to the Casudssion in i confidence and, under the provisions of 10 CFR Section 2.790.

- it is to be received i.n conffdance by the Caserission. -

, (i,y) The 'nfomation is not available in public sources to the 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- .

eent to Westinghouse letter nus6er NS-CE-1298. Eicheidinger to Stol'z. dated December 1,1976, concerning information relating

. to NRC review of WCAP-8567-P and WCAp-8568 entitled, " Improved ,

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Thermal Design Proce(ure," defining the sensitivity of DN8

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ratio p various cars parameters. The letter and attachment i

are being submitted in response p the NRC request at the October 29, 1978 NRC/ West'inghouse meeting.

This infor1mation enables Westinghouse to: .

(a) Justify the Westinghouse design.

(b) ' Assist its customers to obtain licenses.

(c) Nt warranties.

(d) Provide greater operational flexibility to custcmars assuring thee of safe and reliable operation. -

(e) Justify increased power capability or operating eargin

" for plants while assuring safe and reliable operation.

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AW-75-50 (f.) Optimi::e reactor design and perd omance while maintaining a high level of fuel integrity. -

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

(a) Westinghouse uses. the infomation to perform and justify .

analyses which are sold to customers.

. (b) Westinghouse sells analysis services based upon the experience gained and the methods developed. . ,

Public disclosure of this inforspation concerning design pro;

- cadures is likely to cauLe substantial harm to the competitive position of Westinghouse because campetitors could utiiizi' this infomation to assess and justify their ow'n designs-without commiensurate e$ pense. .

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The parametric analyses 2erfomed and their evaluation mpresent '

a considerable amount of highly qualified development effart.

This work was contingent upon a design method development pro-i gram which has been undemay during the past two years. ,

Altogether, a substantial amount of anney and effort has been expended by Westinghouse _ which could only be duplicated by a '

- competitor if he were to invest similar suas of money and pre-vided he had the appropriate talent available. .

Further 'the deponent sayeth not. ,

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. t WESTINGHOUSE PROPRIETARY CLASS 3 RAI'492.6 (4.4)

Your letter of April 25,1983 (J. DeVincentis, Public Service of New Hampshire to G. W. Knighton, NRC) provided a response caperceding your previous response (FSAR Amendment 45, June 1962) to staff question 492.2 regarding the Reactor Coolant System (RCS) flow measurement. The current response included a Westinghouse report for the Seabrook flow measurement uncertainty similar to the gens..; Westinghouse flow measurement uncertainty report (Letter NS-EPR -2577 E. P. Rahe, Westinghouse, to C. H. Berlinger, NRC, March 31, 1982). You concluded that the total flow measurement uncertainty for four lovp operation is: 11.9% using three elbow taps per loop with digital volt meter readout, or i 2.0% using one elbow tap per loop with computer readout.

Also, you indicated that bias due to feedwater flow venturi meter fouling is not included due to methods of confirming that fouling does not exist. In addition, you indicated I. hat crud buildup that could affect the pressure taps on the ventuel and flow .lbow, and that could lead to measurement errors, is not expected and has not been detected in any Westinghouse reactor.

Even though the Westinghouse response reflects the use of RdF RTD transmitters for Seabrook, other instrumentation uncertainties cited are the generic bounding values for Westinghouse instrumentation.

f (a)

Plant-specific instrumentation uncertainties exceeding the bounding values cited in the Westinghouse response should be identified and used for the

plant-specific analysis. Please identify any instrumentation which deviates from the Westinghouse instrumentation and provide the uncertainty value pertinent to this instrumentation and measurement arrangement with comparison to the Westinghouse generic value, i

t WESTINGHOUSE PROPRIETARY CLASS 3 (b)

The bases or sources for the uncertainty value should also be provided. The sources can be from purchase specifications, manufacturing specifications, calibration data provided by instrumentation vendor or obtained on site, published industry standard or other justifiable bases.

(c)

How may elbow taps will be used per loop?

RESPONSE

(a),(b) 1 The measurement arrangement at Seabrook will be the same as assumed by Westinghouse with the following exceptions:

o Feedwater flow will be monitored at the output of the transmitter using a DVM instead of a local gauge, o Feedwater pressure will be read directly off the Main Control Board instruments instead of assuming a pressure 100 psi above steam pressure, i o In order to minimize the number of unisolated protection channel l

measurements, steam pressure and pressurizer pressure will be measured with a DVM at an isolated output. An isolator drif t of .5% is included in the Seabrook specific uncertainty analysis. Also, the uncertainties for these two measurements are calculated rather than assumed.

o If RCS flow is measured with a DVM it will be measured at the output of the transmitter and will not include any rack components.

WESTINGHOUSE PROPRIETARY CLASS 3 The instrumentation used at Seabrook is the same as assumed by Westinghouse with the following exceptions:

o Feed Pressure Transmitter - Seabrook uses a Foxboro E11GM transmitter.

The calibration accuracy for this transmitter as specified by the manufacturer is 0.5% of span, [ ).+"'"

o Feedwater RTDs - Seabrook has Thermo Electric platinum RTDs. The accuracy as specified by the vendor is i 1 F or i 1/2% of reading up to 600 F, whichever is largest.

o Station Computer - The Seabrook Station computer has an A/D conversion error of i 0.2% of full scale based on station experience with the operation of the computer.

o Test Equipment - The test equipment presently identified in station

, procedures for use in calibrating some of the sensors does not always meet the accuracy ratio assumed by Westinghouse. The test equipment accuracies, as specified by the test equipment vendor, have been accounted for in the station specific analysis.

(c)

When available, three elbow taps will be used per loop. The minimum is two elbow taps per loop to moet Technical Specification Table 3.3-1.

A comparison of the uncertainties listed in our letter of April 25, 1983, and those based on seabrook specific instrumentation and procedures is provided in the following table and accompanying notes. Only those notes applicable to Seabrook specific information are included.

Total flow measurement uncertainties based on Seabrook specific instrument uncertainties are:

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WESTINGHOUSE PROPRIETARY CLASS 3 Calorimetric Uncertainty i 1.9%

Total Uncertainty (Computer) (3 Elbow Taps / Loop) i 2.0%

Total Uncertainty (DVM) (3 Elbow Taps / Loop) i 2.0%

Total Uncertainty (Computer) (2 Elbow Taps / Loop) i 2.0%

Total Uncertainty (DVM) (2 Elbow Taps / Loop) i 2.0%

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4 r-WESTINGHOUSE PROPRIETARY CLASS 3 Comparison Of Westinshouse Values To Seabrook Specific Values For RCS Flow Uncertainty h[ Seabrook RCS RCS Component Instrument Flow Instrument Flow Error Uncert. Error Uncert.

Feedwater Flow

+a,c Ventuel K Thermal Expansion Temperature Material Density Temperature Pressure Venturi Fouling Instrumentation dP Cell Calibration dP Cell Cage Readout Sensor Temperature.

Effect DVM Accuracy Total Instrument Error Total FW Flow Error Feedwater Enthalpy Temperature RTD Calibration Sensor Drift DVM Accuracy

. e WESTINGHOUSE PROPRIETARY CLASS 3 W Seabrook-RCS RCS Component Instrument Flow Instrument Flow Error Uncert. Error Uncert.

Feedwater Enthalpy (Cont'd)

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Total Temperature Error Pressure Sensor Calibration Sensor Drift Sensor Temperature Effec Rack Calibration Rack Drift Rack Temperature Effect MCB Readout Total Pressure Error

(% Span)

Total Pressure Error (psi)

Total Feed Enthalpy Error Steam Enthalpy Steamline Pressure Pressure Cell Calibration Sensor Temp. Effect Rack Calibration Rack Temperature Effect Isolator Drift DVM Accuracy Total Electronics Error Pressure Error Assumed Pressure Error Calculated Moisture Carryover Total Steam Enthalpy Error Total Secondary Side Loop i Secondary Side Loop Power Uncertainty 1

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'N Seabrook l

RCS RCS l Component Instrument Flow Instrument Flow  !

Error Uncert. Error Uncert.

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~ ~ l RCP Heat Adder Uncertainty l Total Secondary Side Loop j Power Uncertainty Primary Side Enthalpy ,

TH (Electronics)  ;

RTD Calibration Sensor Drift DVH Accuracy Tg Instrumentation Error TH Streaming Error l

TH Temperature Error l

, TC (Electronics)

RTD Calibration Sensor Drift DVH Accuracy TC Instrumentation Error Pressurizer Pressure

, Pressure Cell Calibration l

Sensor Temperature

Effect Sencor Delft -

Rack Calibration f Rack Drift Rack Temperature Effect Isolator Drift DVH Accuracy

. Total Error Pressurizer Pressure <

Error (Calculated)

Pressuriser Pressure l Error (Assumed)

TH Pressure Effect TH Total Error TC Pressure Effect - -

, i WESTINGHOUSE PROPRIETARY. CLASS 3."

r W faabrook RCS RCS Component Instrument Flow Instrument Flow Error Uncert. Error Uncert.

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TC Total Error

< Total Ah Uncertainty

.Pri mary Si de Loop Flow Uncertainty Total RCS Flow 4

Uncertainty i

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, .s WESTINGHOUSE PROPRIETARY CLASS 3 NORMALIZED ELBOW TAP INSTRUMENTATION UNCERTAINTIES

,. COMPUTER liEASUREMENT Component W Seabrook

% do Span  % RCG Flow  % do Span  % RCS Flow

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-ID A/D Readout CSA DVM MEASUREMENT PMA PEA SD RCA RD DVM f Readout l

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WESTINGHOUSE PROPRIETARY CLASS 3 c 59tes

1. The primary element accuracy for feed flow includes an uncertainty of i.

10.1% for the ability to detect fouling of the venturi.

f 2. Sensor calibration accuracy for feed flow includes an allowance for the test equipment-used to eslibrate the transmitter. Present station procedures call for the use of a Heise gauge with a range of 0-60 psi and

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an accuracy of io.1% or i.06 psi. The span of the feed flow transmitter j is 830" H 0 (30 psi). The test equipment accuracy is 1 2% (.06 psi /30 psi) of feedwater flow transmitter span. Therefore, the .2% test equipment accuracy must be added to the i [ 1+"' calibration accuracy of the transmitter. e l- 3. . Seabrook will not use a local gauge to read dP on tl.e feedwater flow

! venturi, hence, the sensor. temperature effect which [ ] "'

1 neglects because of the local gauge must be accounted for. Also, the DVM

is normally accurate to iO.05% of span, but an allowance of 0.5% span has been'used because of the difficulty in reading the rapidly

. fluctuating dP signal. [(

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))+a c l 4. Span of the Feedwater flow transmitter is 132% instead of the 120%

assumed by Westinghouse.

S. The feedwater RTD accuracy from the vendor is i 1.0 F or 1/2% of i reading up to 600 F. Hence, at 440 F the error is 12.20 F.

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6. Ser.so; calibration accuracy for feed pressure includes an allowance for I the test equipment used to calibrate the transmitter. Present station

!l procedures call for the use of a Heise gauge with a range of 0-3000 psi i and an accuracy of.10.1% or i3.0 psi. ,

The span of the food pressure transmitter is 1500 psi. The test equipment accuracy is i.2% (3.0 i

psi /1500 psi) of feed pressure span. Therefore, the .2% test equipment accuracy must be added to the [ 1**'" calibration accuracy of the transmitter.

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WESTINGHOUSE PROPRIETARY CLASS 3

7. The most inaccurate means to read feedwater pressure is to use the Main Control Board indication. That is what is assumed here.

8. Span.of the steam pressure transmitter is 1300 psi instead cf the 1200 psi assumed by Westinghouse.

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9. SCA for steam pressure includes an allowance for the test equipment used to calibrate the transmitter. Present station procedures call for the use of a Heise gauge with a range of 0-1500 psi and an accuracy of 10.1%

or 11.5 pei. The span of the steam presrttre transmitter is 1300 psi.

The test equipment accuracy is .12% (1.5 psi /1300 psi) of steam pressure span. Therefore, the 10.12% test equipment accuracy must be added to the

[ 1+"'" calibration accucacy of the transmitter.

10. Station procedures call for the DVM measurement of this instrument at the output of the transmitter, thus bypassing the rack and errors associated

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with the rack.

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11. SCA for pressurizer pressure includes an allowance for the test equipment used to calibrate the transmitter. Present station procedures call for the use of a Heise Ashcroft Digigage with a range of 0-3000 psi and an accuracy of 10.05% or 11.5 psi. The span of the pressurizer pressure transmitter is 800 psi. The test equipment accuracy is 10.19% (1.5

! psi /800 psi) pressurizer pressure span. Therefore, the 10.19% test equipment accuracy must be added to the [ ] "'" calibration accuracy of the transmitter.

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i 12. In order to minimize the number of unisolated protection channel measurements, an additional 10.5% isolator drift has been added to the analysis.

13. A rack drift of 10.5% is added for additional conservatism.

i 14 . . The Seabrook Station computer has an A/D conversion error of 10.2% full scale based on operating experience.

.' i WESTINGHOUSE PROPRIETARY CLASS 3

=RAI 492.7 (4.4)

For the RCS flow measurement,' the Westinghouse generic response states: "It is assumed for this error analysis, that this flow measurement is performed within seven days of calibrating the measurement instrumentation, therefore, drift effects are not included (except where necessary due to sensor location)". Does your plant operating procedure have provisions that require the RCS flow measurement be performed within seven days of calibrating the measurement instrumentation? If not, what are the drift uncertainty values associated with each component such as dP cell, local meter, RTD, l thermocouple, process rack and sensors? What is the effect on the overall ,

l1 ' flow measurement uncertainty?

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-RESPONSR Station procedures will require that the process measurement instrumentation which Westinghouse assumed calibrated within seven days of the flow

.: measurement be calibrated or calibration checked within that time frame.

Where the Westinghouse submittal indicated that the DVM had been recently calibrated, this may not always be the case, but a DVM of sufficient accuracy within its calibration period will be used so that the error assumed by Westinghouse for the DVM will not be exceeded. ,,

RAI 492.8 (4.4)

The Westinghouse report states: "It is also assumed that the calorimetric flow measurement is performed at the beginning of a cycle, so no allowance has been made for feedwater venturi crud buildup"; and "If venturi fouling is detected by the plant, the venturi should be cleaned, prior to performance of the measurement. If the ventuel is not cleaned, the effect of the fauling on the determination of the feedwater flow and, thus, the steam generator power and RCS flow should be measured and treated as a bias, i.e., the error due to venturi fouling should be added to the statistical summation of the rest of the measurement errors".

. s WESTINGHOUSE PROPRIETARY CLASS 3 (a) How do you assure that the venturi is clean at the beginning of a cycle?

Is the venturi cleaned at the beginning of every cycle?

L.

(b) How do you detect the venturi fouling and to what extent of uncertainty can you detect fouling?

(c) Describe the design provisions and procedures to clean the ventuel if fouling is detected.

(d) How do you determine the error on feedwater flow measurement due to the fouling effect if the venturi is not cleaned or if the venturi fouling is not detected?

(e) If the venturi is not cleaned prior to the' calorimetric flow measurement because no fouling is detected an error component should be added. The magnitude of the error component should depend oa the minimum detectable value of fouling.

RESPONSE

(a),(b),(d),(e)

The present intent of the station is to determine if venturi fouling exists by trending plant performance. Data that will be trended include:

o Venturi flow measurement versus flow measurement by the sonic flow meter in series with each venturi.

o Feed flow versus steam flow.

o Reactor power versus core differential temperature.

o Reactor power versus generator output with consideration for secondary cycle efficiency.

- - - . - . - . . . - . . . ~ , .- . - . .

o WESTINGHOUSE PROPRIETARY CLASS 3 The plant performance monitoring program will evaluate the trends in the above parameters to determine if ventuel fouling exists and what the consequences are on the measured RCS flow rate. It is anticipated that the parameters being monitored, especially the sonic flow meters in series with the venturies, will provide a high degree of confidence in the detection of venturi fouling.

The sonic flow meters have a repeatability of 0.1% as specified by the manufacturer. Based on the anticipated performance of the sonic flow meter, an uncertainty of 0.1% for our ability to determine whether venturi fouling exists has been included in the response to RAI 492.6. The performance of the sonic flow meters will be monitored and evaluated in the power ascension phase of startup testing.

If and when venturi fouling is detected, either the venturies will be cleaned prior to the next fuel cycle measurement, or corrections to the feed flow measurement will be applied as a bias.

(c)

The feedwater piping does not include design features to specifically clean the venturies. Provisions and procedures to clean the venturies will be established when or if fouling is detected and it is determined that cleaning is warranted.

RAI 492.9 (4.4)

'nie Topical Report WCAP-8691, Revision 1, " Fuel Rod Bow Evaluation", has been approved by the staff. If you plan to reference this, you are requested to provide a new table of rod bow DNBR penalty vs. fuel burnup based on the approved method which will be used in the Technical Specifications.

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WESTINGHOUSE PROPRIETARY CLASS 3 RESPCNSE We do intend to reference the Topical Report WCAP-8291, Revision 1.

Accordingly FSAR Sections 4.2 and 4.4 were revised in Amendment 53. Technical Specifications 3/4.2.3 and BASES 3/4.2.3 will be revised. We have attached a copy of Amendment 53 that is marked-up to correct a typographical error and to provide clarification and a draft copy of the Technical Specification change.

i f

SB 1 & 2 Amendment 53 FSAR August 1984

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Meta 11ographic examination of irradiated commercial fuel rods have shown occurrences of fuel / clad chemical interaction. Reac-tion layers of < 1 mil in thickness have been observed between fuel and clad at limited points around the circumference.- Metallo-graphic data indicates that this interface layer remains very thin even at high burnup. Thus, there is no indication of propagation of the later and eventual clad penetra. tion.

-Stress corrosion cracking is another postulated phenomenon related to fuel / clad chemical interaction. Out of pile tests have shown that in the presence of high clad tensile stresses, large concen-trations of selected fission products (such as iodine) can chemic-ally attack the Zircaloy tubing and can lead to eventual clad cracking. Extensive post-irradiation examination has produced no inpile evidence that this mechanism is operative in Westinghouse-produced commercial fuel.

d. _ Rod Bowing Reference (11) presents the model used for evaluation of fuel rod bowing. Also refer' to Subsection 4.4.2.2.e.

e. Consequences of Power-Coolant Mismatch SS This subject is discussed in Chapter 15.

f. Creep Collapse and Creepdown This subject and the associated irradiation stability of cladding have been evaluated using the models described in Reference (6).

It has been established that the design basis of no clad collapse during planned core life can be satisfied by limiting fuel densi-fication and by having a sufficiently high initial internal rod preaaure.

4.2.3.2 Fuel Materials Considerations l Sintered, high density uranium dioxide fuel reacts only slightly with the clad at core operating temperatures and pressures. In the event of clad defects, the high resistance of uranium dioxide to attack by water protects against fuel deterioration although limited fuel erosion can occur. As i has been shown by operating experience and extensive experim' ental work, the thermal design parameters conservatively account for changes in the thermal performance of the fuel elements due to pellet fracture which may occur during power operation. The consequences of defects in the ' clad are greatly reduced by the ability of uranium dioxide to retain fission' pro-ducts, includin3 those which are gaseous or highly volatile. Observations from several operating Westinghoase supplied pressurized water reactors (Reference (9)) have shown that fuel pellets can densify under irradiation j k j

4.2-21

s SB 1 & 2 Amendment 53 FSAR August 1984

4. Hellman, J. M. (Ed.), " Fuel Densification Experimental Results and

(

Model for Reactor Application," WCAP-8218-P-A (Proprietary) and WCAP-8219-A, (Non-Proprietary), March, 1975.

5. Miller, J. V. (Ed.), " Improved Analytical Models Used in Westinghouse Fuel Rod Design Computations," WCAP-8720 (Proprietary) and WCAP-8785 (Non-Proprietary), October, 1976.

6. George. R. A., Lee, Y. C. and Eng. C. H., " Revised Clad Flattening Model," WCAP-8377 (Proprietary) and WCAP-8381 (Non-Proprietary),

July, 1974.

7. Risher, D. H.. et al., " Safety Analysis for the Revised Fuel Rod In-ternal Pressure Design Basis," WCAP-8963 (Proprietary), November, 1976 and WCAP-8964 (Non-Proprietary), August, 1977.

8. Cohen, J., " Development and Properties of Silver Base Alloys as Con-trol Rod Materials for Pressurized Water Reactors," WAPD-214, December, 1959.

9. Eggleston, F. T. , " Safety-Related Research and Development for West-saghouse Pressurized Water Reactors, Program Summaries-Winter 1977-Summer 1978," WCAP-8768, Revision 2, October 1978.

10. Demario, E. E., " Hydraulic Flow Test of the 17 x 17 Fuel Assembly,"

WCAP-8278 (Proprietary) and WCAP-8279 (Non-Proprietary), February, (

1974.

11. Skaritka, J. (Ed.), " Fuel Rod Bow Evaluation," WCAP-8691. Revision 1 (proprietary) and WCAP-8692, Revision 1 (non proprietary), July 1979.

12. O'Donnell, W. J. and Langer, B. F., " Fatigue Design Basis for Zircaloy #

Components," Nuclear Science and Engineering, 20, 1-12, 1964.

13. Cesinski, L. , and Chiang, D. , " Safety Analysis of the 17 x 17 Fuel Assembly for Combined Seismic and Loss-of-Coolant Accident," WCAP-8236 (Proprietary) and WCAP-8288 (Non-Proprietary) December, 1973.  ;

14. " Nuclear Fuel Division Quality Assurance Program Plan," WCAP-7800,

Revision 4-A, March, 1975.

15. Skaritika, J. (Ed), " Hybrid B C4 Absorber Control Rod Evaluation Report."

WCAP-8846-A, September, 1976.

t t

4.2-38 L _ _ _ _ - _ _ _ . . _ - - - - _ - _ _ _ - - -- - - ~ ~ - - - --i

o SB 1 & 2 Amendment 53 FSAR August 1984

(

while the fuel rod diameter, pitch and bowing variation including inpile effects is considered in the preparation of the TilINC input values such as axial flow area, equivalent

, hydraulic diameter and lateral crossflow area for the hot channel.

(b) Inlet Flow Ma1 distribution The consideration of inlet flow maldistribution in core thermal performances is discussed in Subsection 4.4.4.2b. A design basis of 5 percent reduction in coolant flow to the hot assembly is used in the THINC-IV analysis.

(c) Flow Redistribution The flow redistribution accounts for the reduction in flow in the hot channel resulting from the high flow resistance in the channel due to the local or bulk boiling.

The ef fect of the non-uniform power distribution is inherently considered in the THINC analysis for every operating coadition which is evaluated.

(d) Flow Mixing i

i The subchannel mixing model incorporated in the THINC Code and used in reactor design is based on experimental data, Peference (17), discuss.ed in' Subsection 4.4.4.5a.

The mixing vanes incorporated _in the spacer grid design induce additional flow mixing between the various flow channels in a fuel assembly as well as between adjacent assemblies. This mixing reduces the enthalpy rise in the hot channel resulting from local power peaking or unfavorable mechanical tolerances.

l te) Effects of Rod Bow on DNBR l

The phenomenon of fuel rod bowing, as described in Reference (80),

, must be accounted for in the DNBR safety analysis of Condition I

l. and Condition II events for each plant application. Applicable I generic credits for margin resulting from retained conservatism in the ' evaluation of DNBR and/or magr in obtained from measured plant operating parameters (such as lhH or core flow), which are less l limiting than those required by the plant safety analysis, can be l used to offset the effect of rod bow. ,e For the sa fe lysis of Seabrook Unit 1, sufficient Amrgin was l maintained to accommodate full and low flow DNBR' penalties identified ir Reference (81).

(jrgf TW5 54 TM wow UM WthcM 11 A GUMuf of 3)JM*W*k p l

4.4-12

i

. s SB 1 & 2 Amendment 53 FSAR August 1984 The maximum rod bow penalties accounted for in the design safety analysis are based on an assembly average burnup of 33000 MWD /MTU.

At burnups greater than 33000 MWD /MTU, credit is taken for the effect of (gj burndown, due to the decrease in fissionable isotopes and the buildup of fission product inventory, and no additional-rod bow penalty is required.

53 4.4.2.3 Linear Heat Generation Rate The core average and maximum LHGRs are given in Table 4.4-1. The method of determing the maximum LHGR is given in Subsection 4.3.2.2.

4.4.2.4 Void Fraction Distribution The calculated core average and the hot subchannel maximum and average void fractions are presented in Table 4.4-3 for operation at full power with design hot channel factors. The void fraction distribution in the core at various radial and axial locations is presented in Reference (18). The void models used in the THINC-IV computer code are described in Subsection 4.4.2.7c. Normalized core flow and enthalpy rise distributions are shown in Figures 4.4-5 through 4.4-7.

(

I

• - Design Limit DNBR of 1.30 vs. 1.28 ,

Crid Spacing (Ks) of 0.046 vs. 0.059 Thermal Dif fusion Coefficient of 0.038 vs. 0.059 DNB Multiplier o f 0.86 Pitch Reduc tion 4.4-12a

SB 1 & 2 Amendment 53 FSAR August 1984

77. Ohtsubo, A., and Urtmashi, S., " Stagnant Fluid due to Local Flow Blockage," J..N,1cl. Sci. Technol. , 9, No. 7, 433-434, (1972).

78. Basmer, P., Kirsh, D. and Schultheiss, G. F., " Investigation of the Flow Pattern ir,the Recirculation Zone Downstream of Local Coolant Blockages in Pin Bundles," Atomwirtschaft, 17, No. 8, 416-417, (1972). (In German).

79. Burke, T. M. , Meye.r, C. E. and Shefcheck J. , " Analysis of Data -

from the Zion (Unit 1) THINC Verification Test," WCAP-8453-(Pro-prietary), December, 1974 and WCAP-8454, December, 1974.

80. Skaritka, J. (Ed.), " Fuel Rod Bow Evaluttion," WCAP-8691, Rev. 1

-(proprietary) and WCAP-8692, Rev. 1 (No -Proprietary), July 1979.

81. " Partial Response to Request Number 1 for Additional Information on WCAP-8691, Rev.1," letter from E. P. Rahe, Jr. , (Wes tinghouse),

to J. R. Miller (NRC), NS-EPR-2515, dated October 9,1981; " Remain-ing Response to Request Number 1" letter, from E. P. Rahe, Jr. ,

(Westinghouse), to R. J. Miller (NRC), NS-EPR-2572, dated March 16, 1982.

55)

(

P

\

t

?

\

i 4.4-43 ,

i L

SB 1 & 2

_ POWER DISTRIBUTION LIMITS 3/4.2.3 RCS FLOW KATE AND R LIMITING CONDITION FOR OPERATION Rc s 3.2.3 The combination of Wip9p A J Reacte- Cre!=t Cyne M total flow rate and Ri gg shall be maintained within the region of allowable operation chown on Figure 3.2-3 for 4 loop operation.

Where:

N FAH

a. R1

=

1.49 [1.0 + 0.2 (1.0 - P)]

" h\

l-MPMk)\

b

• THERMAL POWER I* RATED THERMAL POWER

/. F{ H

=

Measuredval.:sofF{Hobtainedbyusingthe movable incore detectors to obtain a power distribution' map. ThemeasuredvaluesofF$H shall be used to calculate R since 4

Fi ure 3.2-3 includes measurement uncertainties of for flow and 4% for incore measurement of F$ H, an .D m m m m W8 e- kO M a c ae u r n m w - = m h l

49 0 %

APPLICABILITY: MODE 1 l

1 ACTION:

With the combination of RCS total flow rate andi R k outside the region of acceptable operation shown in Figure 3.2-3: .

f si 9

3/4 2-9 i

SB 1 & 2 POWER DISTRIBUTION LIMITS ACTION: (Continued)

a. Within 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />s:

. 1. Either restore the combination of RCS total 'ilow rate and Ri g

\JG to within the above limits, or

2. Reduce THERMAL POWER to less than 50% of RAT 2D THERMAL POWER and reduce the Power Range Neutron Flux - High trip setpoint to less than or equal to 55% of RATED TECRMAL POWER within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

b. Within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of initially being outside the above limits, verify through incore flux mapping and RCS total flow rate comparison that the combination of R i g and RCS total flow rate are restored to within the above limits, or reduce THERMAL POWER l to less than 5% of RATED THERMAL POWER within the next 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

i

c. Identify and correct the cause of the out-of-limit condition-prior to increasing THERMAL POWER above the reduced THERMAL POWER limit required by ACTION items a.2 and/or b. above; subsequent POWER OPERATION may proceed provided that the combination of R g/4PA i and

' 4cdieete& RCS total flow rate are demonstrated, through incore flux mapping and RCS total flow rate comparison, to be within the

• region of acceptable operation shown on Figure 3.2-3 prior to exceeding the following THERMAL POWER levels:

1. A nominal 50% of RATED THERMAL POWER, l

2. A nominal 75% of RATED THERMAL POWER, and

(

l

3. Within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of attaining greater than or equal to 95% of RATED THERMAL POWER.

SURVEILLANCE REQUIREMENTS 4.2.3.1 The provisions of Specification 4.5.4 are not applicable. .

h 4.2.3.2 The combination of h'aa RCS total flow rate and RgM shall l

j. be determined to be within the region of acceptable operation of Figgre 3.2-3: i i

3/4 2-10

.a. q -

SB 1 & 2 POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS (Continued)

a. Prior to operation above 75% of RATED THERMAL POWER af ter each

. fuel loading, and

b. At least once per 31 Effective Full Power Days.

4.2.3.3 The indi..;i? RCS total flow rate shall be verified to be within l

the region of acceptable operation of Figure 3.2-3 at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when the most recently obtained value\ of R 1*gp(pqg, obtained per Specification 4.2.3.2, 9s4w assumed to exist.

IS 4.2.3.4 The RCS $ flow rate indicators shall be subjected to a CHANNEL CALIBRATION at least once per 18 months.

l 4.2.3.5 The RCS total flow rate shall be determined by measurement at least once per 18 months.

i l

P '

3/4 2-11 l

I 1

55 i MEASUREMENT UNCERTAINTIES JOF FOR FLOW AND 4% FOR gg # INCORE MEASUREMENT OF Fag ARE INCLUDED IN THIS FIGURE ACCEPTABtf OPERAftON $

HE6tC%$ -

50

• ND )

( NBttMW

! (

[ ACCEPTABLE OPERATION hNACCEPTABLE g REGIONNW ( OPERATION w ) REGION

(

g" 45 / 5 d

a )

N g h M t

40 . - -

(1,3e52)

,39.0 l

l l

[

35 0.96 0.98 1.00 1.02 1.04 N

Rj=FAH/1.49 [1.0 + 0.2 (1.0.P)]

! _ , i/I , AB" '"Un-l l

l

! FIGURE 3.2-3 i

RCS TOTAL FLOW RATE VERSUS R I FOUR LOOP OPERATION I 3/4 2-12

b

.o4 I

SEABROOK UNIT 1

.o3

{ ,/' ( 33.0.0.0? 6 )

/

a

$0 a.

/

f

/

8 O

e N f.

J21.6,0) \

.00 /

15 20

'N 2s 30 as 3

/ REGION AVERAGE BURNUP (10 MWD /MTU)

S O

e FIGURE 3.2-4 ROD BOW PENALTY AS A FUNCTION OF BUHNUP 3/4 2-13

m -

, .g .

SB 1 & 2 POWER DISTRIBUTION LIMITS BASES

., Each of these is measurable but will normally only be determined periodically as specified in Specifications 4.2.2 and 4.2.3. This periodic surveillance is sufficient to insure that the limits are maintained provided:

I

a. Control rods in a single group move together with no individual rod insertion differing by more than + 12 steps, indicated, from the group demand position.

b. Control rod groups are sequenced with overlapping groups as described in Specification 3.1.3.6.

c. The control rod insertion limits of Specifications 3.1.3.5 and 3.1.3.6 are maintained.

d. The axial power distribution, expressed in terms of AXIAL FLUX DIFFERENCE, is maintained within the limits.

i FyHwillbemaintainedwithinitslimitsprovidedconditionsa.through

d. above are maintained. As noted in Figure,( 3.2-3 end-3 rem &, RCS flow rate l and F[H may be " traded off" against one another (i.e., a low measured RCS flowrateisacceptableifthemeasuredFfH is also low) to ensure that the calculated DNBR will not be below the design DNBR value. The relaxation of F H as a function of THERMAL POWER allows changes in the radial power shape or all permissible rod insertion limits.

R1 as calculated in 3.2.3 and used in Figure 3.2-3, accounts for FfH less than or equal to 1.49. This value is used in the various accident analyses where F influences parameters other than DNBR, e.g., peak clad temperature, an thus is the maximum "as measured" value allowed. E2,_.

defi..sJ, 21!: : fer t'e fre!" 4-- ^f : ;:rrit; '-- -^A ha" ^^ """" ^ '77 tk"' ' ^1 : c.. ;bs ".. -cosuica" .;I-^- ar pN ..; oce ci- i s ---- r-.

";._J::ff;" i mouc ui R c3uoi :: !_0 r^'# ^ ;x:pc - ^r rf c;;:ng e ;_5 L.- u ma ym..;I:y.

el rod bowing reduces the value of DNB ratio. Sufficient cred* ,

available set this reduction. This credit comes from . c design margins totalling . 3% margin in the differe ween the 1.3 DNBR safety limit and the minimum alculate the Complete Losi of Flow event. The penalties applied to F ount for Rod Bow (Figure 3.2-4) as a function of burnup ar sastent with t escribed in Mr. John F.

Stolz's (NRC) le T. M. Anderson (Westinghouse rii 5, 1979 and W 86 v. 1 (partial rod bow test data).

B 3/4 2-5 s

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

A SB 1 & 2 v

POWER DISTRIBUTION LIMITS BASES When an Fq measurement is taken, an allowance for both experimental I

error and manufacturing tolerance must be made. An allowance of 5% is appro-priate for a full core map taken with the incore detector flux mapping system 4

and a 3% allowance is appro,ariate for manufacturing- tolerance.

When RCS flow rate and F necessarypriortocomparison$Haremeasured,noadditionalallowancesare with the limits of Figureh 3.2-3 _;d 2.7 1.

2 ' ()

l Measurement errors of]Q4jk for RCS total flow rate and 4% for FfH have been allowed for in determination of the design DNBR value. ,

The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> periodic surveillance of indicated RCS flow is sufficient

,~

to detect only flow degradation which could lead to operation outside the

-acceptable region of operation shown on Figure 3.2-3.

i e

3/4.2.4 QUADRANT POWER TILT RATIO The quadrant power tilt ratio limit assures that the radial power distri-

, bution satisfies the design values used in the power capability analysis.

Radial power distribution measurements are made during startup testing and l periodically during power operation.

l The limit of 1.02, at which corrective action is required, _ provices DNB and_ linear heat generation rate protection with x-y plane power til:s.

l The two hour time allowance for operation with a tilt ' condition greater than 1.02 but less than 1.09 is provided to allow. identification and correc-tion of a dropped or misaligned control rod. In the event such action does not correct the tilt, the margin for uncertainty on Fq is reinstated by reduc-ing the maximum allowed power by 3 percent for each percent of tilt in excess of 1.0.

. 3/4.2.5 DNB PARAMETERS

! The limits on the DNB'related parameterr assure that each of the para-meters are maintained within 'the normal steady state envelope of operation - '

assumed in the transient and accident analyses. The limits are consistent .

• with the initial FSAR assumptions and have been analytically demons,trated adequate to maintain a minimum DNBR of 1.30 throughout each analyzep transient. ,

f The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> periodic surveillance of these parameters through' instrument readout is sufficient to ensure that the parameters 'are restored within their ,

[

limits following _ load changes and other expected transient operation. g I

a B 3/4 2-6 ,

i.

_ ..,_m.., _ -

~ . . . . . , _ . . . - - . _ _ , . _ - , . . . . . _ , ,. __ _ _ . . , _ _ _ , _ , _ _ _ _ . , _ _ _ , , , . _ , . -