ML20052F519

Forwards Proprietary & Nonproprietary Versions of Response to NRC Questions on Improved Thermal Design Procedures. Authorizes Use of Proprietary Info by Comm Ed.Proprietary Info Withheld (Ref 10CFR2.790).Affidavit (AW-76-60) Encl

ML20052F519
Person / Time
Site:	Byron, Braidwood, 05000000
Issue date:	04/06/1982
From:	Wiesemann R WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML19274C073	List: ML20052F513 ML20052F519
References
AW-76-60, CAW-82-15, NUDOCS 8205130138
Download: ML20052F519 (18)

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NuclearTecnnology Dinion Westinghouse Water Reactor ~

Electric Corporation Divisions Box 355 PittsburghPennsylvania15230 April 6,1982 CAW-82-15

c. Harold R. Denton, Director 0.ffice of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20014

SUBJECT:

Westinghouse response to NRC questions on Improved Thermal Design Procedures for Byron /Braidwood REF: Commonwealth Edison letter, Tramm to Denton, April 1982

Dear Mr. Denton:

The proprietary material for which withholding is being requested by Common-wealth Edison Company is proprietary to Westinghouse and withholding is requested pursuant to the provisions of paragraph (b)(1) er Section 2.790 of the Commission's regulations. Withholding from public disclosure is requested with respect to the subject information which is further identified in the affidavit accompanying this application.

The proprietary material transmitted by the referenced letter supplements the proprietary material previously submitted. Further, the affidavit sub-mitted to justify the previous material was approved by the Commission on April 17,1978 and is equally applicable to the subject material.

Accordingly, withholding the subject information from public disclosure is requested in accordance with the previously submitted affidavit, AW-76-60, a copy of which is attached.

Accordingly, this letter authorizes the use of the proprietary information and affidavit CAW-82-15 by the Commonwealth Edison Company for the Byron /

Braidwood Units.

Correspondence with respect to this application for withholding or the accom-panying affidavit should reference CAW-82-15 and be addressed to the under-signed.

Very truly yours,

/bek Robert A. Wiesemann, Manager Enclosure Regulatory & Legislative Affairs __

cc: E. C. Shomaker, Esq.

Office of the Executive Legal Director, NRC 9205130138 020505 PDR ADOCK 05000454 E PDR

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. AW-76-60

. AFFIDAVIT COMMONWEALTH OF PENNSYL'/ANIA:

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. .. COUNTY OF ALLEGHENY: ,

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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 Westinghouse Electric Corporation (" Westinghouse") and that the aver-

' ments of fact set forth in this Affidavit are true and correct to the best of his knculedge, information, and belief:' ~ . . . .

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- Robert A. Wiesemann, Manager ticensing Programs l -

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Sworn to and subscribed before,methisI day of $bhabl 1976. .

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, p l 4 / Notary Puolic. .,,

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AW-76-60 (1) I am Manager, licensing Programs, in the Pressuri:ed Water Reactor 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 frem public dis-closure in connection with nuclear power piant licensing or rule-

' making proceedings, and an authori,ied to apply for its withholding on behalf of the Westinghouse Water Reactor Divisions.

(2) I un making this Affidavit in conformance with the provisions of 10 CFR Section 2.790.of the Commission's regulations and in con-junction with the Westinghouse application for withholding ac-companying this Affidavit. .

(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse Nuclear Energy Systems in designating information .

as a trade secret, privileged or as confidential commercial or

' financial information.

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

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of the Commission's regulations, the following is furnished for consideration by the Cc= mission in determining whether the in-formation sought to be withheld from public disclosure should be l wi thheld. -

- (i) The information sought to be withheld'frem public disclosure l

. is owned and has been held in confidence by Westinghouse.

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-3 AW-76-60 (ii) The information is' of a type customarily held in confide,nce by .

Westinghouse and not customarily disclosed to the public.

Westinghouse. has a

• rational basis for determining the types of .

information customarily held in confidence by it and, in that

. connection, utilizes a. system to determine when and whether to hold certain types of informayion in confidence. The ap-plication of that syste.m and the substance of that system constitutes Westinghouse policy and provides the rational basis required.

Under that system, information is held in ccnfidence if it falls in one or more of several types', the release of which

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

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(a) The information reveals- the distinguishing aspects of a *

. process (or component, structure, tool, method, etc.)- '

where prevention of its 'une by any of Westinghouse's j competitors without license from Westinghouse constitutes -

a competitive econcmic advantage over other companies.

(b) It consists of supporting data, including test data, relative to a process '(or ccrponent, structure, tool, method, etc.), the application of which data secures a competitive economic advantage, e.g. , by optimization or improved marketability.

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AW-75-60

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(c) Its use by a competitor would reduce his expenditure -

of resources or improve his competitive position in the

.c design, manuf~acture, shipment, instdlation, assurance of quality, or licensing a similar product. .

(d) It reveals cost or prica[1nfomation, production cap-i , cities, budget levels, or comercial strategies of a

Westinghouse, its customers or suppliers.

(e) It revealt aspects of past, present, or f'uture West-inghouse or customer funded development plans and pro-grams of potential commercial value to Westinghouse. .

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

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taction may be desirable. -

- (g) It is 'not the prop' rty. e of Westinghouse, but must be treated

• as proprietary by Westinghouse according to ,-

agreements with the owner.

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

(a) The use of such information by Westinghouse gives

- Westinghouse a competitive advantage over its ccm- ,

petitors. It is, therefore, withheld from disclosure f -

- to protect the Westinghousa competitive position.

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AW-76-60

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It is ,information which is marketable in many ways.

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, (b)

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

sell products and services involving the use of the

. information.

(c) Usa by our competitor we'uld put Westinghouse at a comp'etitive disadvantage by reducing his expenditure

- of resources at our expense. .

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

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competitors acquire components.cf proprietary infor-mation, any one component may,be the key to the entire l - ,

puzzle, thereby depriving Westinghouse of a competitive i .

advantage. *

, j (e). Unrestricted disclerure would. Jeopardize the position

• 7 of prominence of Westinghous5 in the world market, and thereby give a market advantage to the competition in those countries. .

(f) The Westinghouse capacity to invest corporate assets in research and development depends upon the success in obtaining and maintaining a competitive advantage.

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AW-76-60 (iii) The information is being transmitted to the Ccamission in

- confidence and, under the previsions of 10 CFR Section 2.790, it is to be received in confidence by the Ccmmission. -

(i,y) The 'nformation is not available in public sources to the best* of our knowledge and beljef.

(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 number NS-CE-1298, Eicheldinger to Stol'z, dated December 1,1976, concerning information relating

. to NRC review of WCAP-8567-P and WCAP-8558 entitled, " Improved ,

. Thermal Design Procedure," defining the sensitivity of DNS ratio p various core riarameters. The letter and attachment "

are being submitted in response to the NRC request at the October 29, 1976 NRC/ Westinghouse =eeting.

i This infonnation enables Westinghouse to: .

l (a) Justify the Westinghouse design.

(b) ' Assist its customers to obtain licenses.

(c) Meet warranties.

(d) Provide greatero' perational fle.xibility to cust:mers

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assuring them of safe and reliable operation. .

(e) Justify increased power capability or operating margin for plants while assuring safe and reliable operation.

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AW-76-60 (f.) Optimize reactor design and performance while maintaining a high level of fuel integrity. -

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

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

analyses which are sold to customers.

(b) Westinghouse selks analysis services based upon the

- experience gained and the methods developed. .

Public disclosure of this information concerning design pro-cedures is likely to cause substantial harm to the competitive position of Westinghouse because competitors could utiiize' this information to assess and justify their ow'n designs without comm'ensurate e$ pense.

The parametric analyses gerformed and their evaluation represent a considerable amount of highly qualified development effort.

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

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-vided he had the appropriate talent available.

Further 'the deponent sayeth not. ,

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' i' ATTACHMENT 1

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Resconse 221.3 Tne fc11owing is the additional informaticn recuested on the Byron /Braidwood acplication of the Westinghouse Improved Thermal Design Procedure. Each of the items will be addressed individually. Items (3), (4), and (6) were addressed generically in some detail and submitted to the staff in NS-EPR-2577. As stated in that submittal, the plant specific responses to these items will supplement the generic response, serving only to note any non-conservative deviation from the generic set and the associated impact (if any) on the process parameters total uncertainties.

(1) Provide the sensitivity factors (5 9) and their range of applicability; The sensitivity factors (S,) and their range of appitcability are given in Table 1 for ~ Byron /Braidwood. .Please note that these values are the same as those used in WCAP-9500 with the exception of the range for Vessel Flow. The range on flow for Byron /Braidwood has been extended down to 273270 GPM (70% flow) with no change in the corresponding sensitivity factor being required. .

(2) If the 5 values used in the Byron /Braidwooc analyses are differend than those used in WCAP:9500, then the applicant must re-evaluate the use of an uncertainty allowance for application of equation 3-2 of WCAP-8567, " Improved Thermal Design Procedure" and the linearity assumption must be l validated. -

The 5 values used in the Byron /Braidwood analyses are the same as those used in WCAP-9500. Therefore, re-evaluating the use of an 9

uncertainty allowance for applicat' ion of equation 3-2 of WCAP-8567,

" Improved Thermal Design Procedure" and the linearity assumption is not required.

(3) Provide and justify the variances and dis-tributions for input parameters.

The distributions assumed for the input parameters such as pressurizer pressure, core average temperature, reactor power, and RCS flow are nonnal, two-sided, 95+% probability distributions.

The variances of these parameters for Byron /Braidwood are consistent with the variances calculated in the generic response. Specifically, the uncertainties for pressurizer pressure and core average temperature are identi' cal to the generic response since the sensors, process racks, and computer and readout devices are standard Westinghouse supplied N,SSS equipment.

Variances in reactor power and reactor coolant system flow are calculated based on equation 4 and equation 8 respectively in reference 1. As can be seen from the equations, both primary and secondary side parameters are measured for power and flow calorimetrics. The error allowances for the parameters measured by Westinghouse supplied equipment are identical to those used in the_ generic submittal (reference 1). Two input parameters are measured by

non-Westinghouse supplied instruments. These are feedwater temoerature and feedwater pressure. As expected, the error allowances for these instruments vary slightly from those used in reference 1. The error allowances for feedwater temperature and pressure were statistically combined (as described in reference 1) to get the total channel allowance for each parameter.

The feedwater pressure error allowance was calculated to be less than the eren" allnwanca used in reference.1. Therefore, the error contribution to the reactor power and flow uncertainties from feedwater pressure is less trian that used in the generic response.

Similiarly, the errors for feedwater temperature were combined to get the total channel allowance. The total allowance was found to be slightly higher than that used to calculate RCS flow uncertainty in reference 1. However, the error allowance from feedwater temperature is very small relative to the other contributing errors and in fact this small additional error is absorbed in the statistical combination. Therefore, the flow uncertainty calculated in reference 1 is applicable for Byron /Braidwood.

As stated in reference 1, the flow calorimetric can be perfanned one of several ways. Commonwealth Edison plans to do a precision flow calorimetric at the beginning of the cycle and normalize the loop elbow taps. For monthly surveillance to assure plant operation consistent with the ITDP assumptions, the loop flows will be read off' of the plant process computer. The tetal flow uncertainty associated with this method was calculated in reference 1 and is a}pplicable to the Byron /Braidwood units.

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lt is to be noted that the total channel allowance for feedwater temperature was calculated to be less than the error assumed for the reactor power uncertainty calculation in reference 1. Therefore, the power uncertainty for Byron /

Braidwood is bounded by the uncertainty calculated in the generic response.

(a) Justify that the normal conditions used in the analyses bound all permitted modes of plant operation.

This item was addressed in reference 1 and is applicable to the Byron /Braidwood units.

(5) Provide a discucsion of what uncertainties, including their values, are included in the DNBR analyses; ,

The uncertainties included in the ITDP DNBR analyses for Byron /Braidwood are given in Table 1. As a result of these values being different from those used in WCAP-9500, the Design DNBR Limits also differ. The calcu-lation of the Design Limit DNBR's for the Typical and Thimble cells are given in Tables 2 and 3 respectively. Since the Design DNBR Limits given in Tables 2 and 3 are different from those originally given in the Byron /Braidwood FSAR, additional changes are required. These changes are addressed in Attachments 2 and 3.

(6) Provide a block diagram depicting sensor, processing equipment, computer ano readout devices for each parameter channel used in the uncertainty analysis. Within eacn element of the block diagram identify the accuracy, drift, 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.

Block diagrams will not be provided in this response. However, as in the generic response a table is provided giving the error breakdown from sensor to computer and readout' devices. This table is abbreviated though, giving only the error breakdowns for instruments that differ from those in Table 4,

" Typical Instrument Uncertainties", of reference 1. As noted earlier, these.

instruments are those that measure feedwater temperature and pressure.

(7) If there are any changes to the THINC-IV correlation, or parameter values outside of previously denonstrated acceptable ranges, the

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staff requires a re-evaluation of the sensitivity factors and of the use of equation 3-2 of WCAP-8567 Fo~r Byron /Braidwood, the THINC-IV code and WRB-1 DNB

' Correlation are the same.as that used in WCAP-9500. Therefore, '

re-eyaluating the sensitivity factors and the use of equation 3-2 af'WCAP-8567 is not required.

References-

1. Westinghouse letter, NS-EPR-2577, E. P. Rahe to C. H. Berlinger (NRC),

March 31, 1982.

ATTACHMENT 2 l

As 'a result of revised Design DNBR Limits (Typical and Thimole cells) #or l Byron /Braidwood, the FSAR originally prepared requires a change to these values.

The values of 1.33 for the Typical Cell Design DNBR Limit should be changed to a value of 1.34 throughout the FSAR (and Technical Specifications).

Accordingly, the value of 1.31 for the Thimble Cell Design DNBR Limit should be changed to a value of 1.32. In the Byron /Braidwood FSAR Chapter 4.4, these DNBR limits are specified on pages 4.4-2 (each twice), 4.4-3, and in Figure 4.4-1 (thimble cell only). It should be noted that the changes to the Design DNBR Limit do not effect any previously related DNBR safety analyses. The ,

Safety Analysis DNBR Limits of 1.49 and 1.47 (for typical and thimble cells respectively) remain unchanged. The change only affects the DNBR allowance between the Design DNBR Limits and the Safety Analysis DNBR Limits which is not required to meet the design basis. This DNBR allowance is availabl~e for the purpose of increasing operating flexibility in the design, operation, and analysis for the Byron /Breidwood plants. ,

Since a revision to the Byron /Braidwood FSAR is in order, it is suggested 'that the following errors in Chapter 4.4 also be corrected.

Pace 4.4-6, the range for the Equivalent Heated Hydraulic Diameter should read:

0.46 5 dh 1 0.68 inches 2

I Pace 4.4-8, the units on Mass Velocity should be lbm/hr-ft and the bulk outlet quality should read:

-52.1 to -13.5%

ATTACHMENT 3 For the purpose of determining the amount of DNBR margin available to offset rod bow p3nalties, the following relationship must be applied.

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SAFETY ANALYSIS DNBR LIMIT = Des narg For the Byron /Braidwood 0FA application, the Design DNBR Limit is 1.32 for the thimble cell and 1,34 for the typical cell while the safety analysis DNBR limit is 1.47 and 1.49 for the thimble and typical cells respectively. i I

Applying the relationship above results in DNBR margin of 10.2% (th'imble cells) and 10,1% (typical cells) for offsetting rod bow penalties. ' ,

I The amount of fuel rod bowing to be accounted for in the OFA is described in Section 4.2.3.1 of the Byron /Braidwood FSAR and results in the same

- DNBR rod bow penalty as the standard 17x17 fuel assembly.

The current NRC approved licensing position for rbd bow requires a 11.4%

DNBR rod bow penalty for 85% gap closure at full flow conditions and a 14%

DNBR rod bow penalty for 85% gap closure at low flow conditions (e.g. loss-of-flow transient). Gap closure is correlated as a function of region average burnup. At a region average burnup of 33000 MWD /MTU the resulting ' gap closure f This results in a required rod bow penalty of 11.1% for full flow is 84%.

conditions and 13.6% for low flow conditions.

l The effect of rod bow on DNB is only considered for region average burnup burndown effects preclude the fuel g3000 MWD /MTU. Beyond this burnup, F from achieving limiting peaking factor (F N) due to the decrease in fissionable isotopes and the buildup of fission product inventory.

At full flow conditions, the amount of DNBR margin available to offset the required rod bow penalties is within 1,0". of that required (11.1% - 10.1%).

Sufficient operating plant margin exists at low flow conditions to offset the addi tional 2.5 % (13.6% - 11.1". ) penalty between low flow and full flow conditio

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Since the available DNBR margin is not sufficient by 1.0% to offset the current recuired ' rod bow penalty, a reduction in allowable F " as a function of burnuo 3

uould be needed in the form of a Technical Specification limit for Byron /

Braicwood.

However, a proposed revision to the calculation of the rod bow DNBR penal.ty for 17x17 fuel is contained in " Fuel Rod Bow Evaluation," WCAP-8691 (Rev.1),

Westinghouse Proprietary, and WCAP-8692 (Rev.1), non-proprietary, July,1979, and is currently undergoing NRC review. This revised calculation reduces the magnitude of the rod bow DNBR penalty to a value less than the U11% DNBR margin retained from above.

Since NRC approval of WCAP-8691 (Rev.1) is anticipated in the near future, and since the final Byron /Braidwood Technical Specifications is not expected to be N

completed until later in 1982, no rod bow penalty on allowable FaH is recommended.

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TABLE l '

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Byron /Braidwood ITDP ,-[

Sensitivity

(% DNBR/% Parameter)'

Uncertainty Equivalent Typical Thinble Parameter Nominal Value Range Standard Deviation Cell Cell .

• (a,c)

Power 100% Power Inlet Tenperature 558.5*F .

Pressure 2280 psia Vessel Flow 390390 GPM Effective Flow 0.957 Fraction (Bypass)

F gg 1.49 E

Fg .1 1.0 TillNC IV -

Transient Code -

e

TABLE 2

.' Calculation of Design DNBR Limit for Typical Cell

=

2 S1( )2 +S 2 (") +....S n 2( )2

($)2 where: o= Standard deviation u= mean 5= sensitivity Parameter Mean (u) o e/u S S2 (o): +(a,c)

Power 1.0 T 558.5 in Pressure 2280 Flow 1.0 Bypass .957 F 1.49 E

F g, 1.0 THINC IV 1.0 Transient Code 1.0 -

I=.0056785

= .07 E 6 (f)y =dSn ( n)

=

Correlation Limit

.~. Design DNBR Limit l-(Comoineo o) (1.645) 1.17 1-(.075356)(1.645)

Design DNBR Limit = 1.3G6

f'yUe Q

= , . ..

TABLE 3 Calculation of Design DNBR Limit for Thimole Cell

= ) +S 2 ( ) *****S ( )

( ) Si( n where: e= Standard deviation u= mean S= sensitivity .

Mean (u) e e/u S S2( )2 +(a,c)

Parameter -

Power 1.0 T 558.5 in Pressure 2280 Flow 1.0 Bypass .957 N 3,49 F

3 Fj,7 1.0 THINC IV 1.0 Transient Code 1.0 -

r=.'0045985

= .067812 (f)y =dSn ( n)

=

Correlation Limit

.. Design DNBR Limit 1-(Comoined a) (1.645) 1.17 l-(.067812 )(1.645)

Design DNBR Limit = 1.317

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? TABLE 4 IflSTRUMENT UtiCERTAIf1 TIES Feedwater(2) Feedwater(2) Feedwater(2)

Temperature Temperature Pressure Indication Indication Indication (computer) (DVM) (computer)

Process Measurement Accuracy --- --- ---

Primary Element Accuracy --- ---

Sensor Calibration Accuracy 0.5 0.5 0.4 Sensor Drift .

--- --- 1.0 S:nsor Temperature Effects --- --- 0.5 S:nsor Pressure Effects ---

Rack Calibration (I} ---

Rack Drift ---

[

f --- ---

Rack Temperature Effects ---

Digital Volt Meter --- 0.2 ---

Computer Isolator Orift --- ---

0.1 --- 0.1 Analog to Digital Conversion . . _ _ __ __ _ . . . . . _ _._ .

Controller Accuracy ,

+a , c Channel Statistical Allowance u 600*F 600*F 2000 psi Instrument Span Instrument' output goes straight to plant process computer. Therefore (1) rack inaccuracies are all zero.-

(2) Uncertainties in percent instrument span.

(3) Determined by methodology described in generic response.