ML20023C188

Forwards Nonproprietary & Proprietary Responses to Questions 440.5,10,11 & 12 on Steam Line Break Method,Resolving SER Confirmatory Items 14 & 15.Proprietary Responses Withheld (Ref 10CFR2.790).Affidavit Encl

ML20023C188
Person / Time
Site:	05000470
Issue date:	05/10/1983
From:	Scherer A ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY
To:	Thomas C Office of Nuclear Reactor Regulation
Shared Package
ML19301C239	List: ML20023C188
References
LD-83-042, LD-83-42, NUDOCS 8305120185
Download: ML20023C188 (19)

Text

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C-E P*w:r Syst!ms Tel 203/688-1911 Combustion Engineering. Inc Telex 99297 1000 Prospect Hill Road Windsor. Connecticut 06095 M POWER SYSTEMS Docket No. STN 50-470F May 10,1983 LD-83-042 Mr. Cecil 0. Thomas, Chief ,

Standardization and Special Projects Branch Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

CESSAR-F SER Confirmatory Item 14, Responses to Questions

References:

(A) Letter, C. O. Thomas to A. E. Scherer, dated February 7,1983 (B ) Letter LD-83-027, A. E. Scherer to C. O. Thomas, dated March 29, 1983 (C) Letter LD-83-036, A. E. Scherer to C. 0. Thomas, dated April 26, 1983

Dear Mr. Thomas:

Reference (A) transmitted in its Enclosure (1) a set of questions on the small feedwater and small steam line break methodologies. Responses to questions one through four which address feedwater line break methodology (Confirmatory Item

15) were provided via Reference (B). A partial response to the question.s on small steam line break methodology was prepared and transmitted to the Staff earlier; Reference (C) transmitted responses to questions 6, 7, 8, 9 and 13.

The responses to tne remaining four questions (5,10,11 and 21) are enclosed.

We believe that the information provided in response to the thirteen questions addresses the Staff's concerns with small steam line break and feedwater line break methodologies and, thus, should resolve Confirmatory Items 14 and 15 of the CESSAR-F SER.

Due to the proprietary nature of the material contained in the enclosure, we request that it be withheld from public disclosure in accordance with the provisions of 10 CFR 2.790 and that this material be safeguarded. The reasons for the proprietary classification of this report are delineated in the enclosed affidavit.

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Mr. Cecil 0. Thomas LD-83-042 May 10, 1983 Page 2 o .

If I can be of any further assistance in this matter, please contact me or Mr.

G. A. Davis of my staff at (203) 688-1911, extension 2803.

Very truly yours, COMBUSTION ENGINEERING, INC.

ft M A. . Scherer Director Nuclear Licensing AES:las F72006 cc: Gary Meyer (Project Manager / USNRC) w/o encl.

Enclosures:

1-P to LO-83-042, " Responses to Questions 440.5,10,11 and 12 on SLB Method", Proprietary Version, (copies 00001 - 00025) 1-NP to LD-83-042, " Responses to Questions 440.5, 10, 11 and 12 on SLB Method", Non-Proprietary Version, (15 copies)

Affidavit attesting to the proprietary nature of this report 1

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AFFIDAVIT PURSUANT TO 10 CFR 2.790 Combustion Engineering, Inc. )

State of Connecticut )

County of Hartford ) SS.:

I, A. E. Scherer, depose and say that I am the Director, Nuclear Licensing, of Combustion Engineering, Inc., duly authorized to make this affidavit, and have reviewed or caused to have reviewed the information which is identified as proprietary and referenced in the paragraph immediately below. I am submitting this affidavit in conformance with the provisions of 10 CFR 2.790 of the Commission's regulations for withholding this information.

The information for which proprietary treatment is sought is contained in the following document:

Enclosure 1-P to LD-83-042, Responses to Questions 440.5, 10, 11, and 12 on SLB Method, May 1983.

This document has been appropriately designated as proprietary.

I have personal knowledge of the criteria and procedures utilized by Combustion Engineering in designating information as a trade secret, privileged or as confidential commercial or financial information.

Pursuant to the provisions of paragraph (b) (4) of Section 2.790 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure, included in the above referenced document, should be withheld.

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1, The information sought to be withheld from public disclosure are the three-dimensional reactivity feedback credits which is owned and has been held in confidence by Combustion Engineering.

2. The information consists of test data or other similar data concerning a process, method or component, the application of which results in a substantial competitive advantage to Combustion Engineering.

3. The information is of a type customarily held in' confidence by I

Combustion Engineering and not customarily disclosed to the public. Combustion Engineering 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 information in I

confidence. The details of the aforementioned system were provided to the Nuclear Regulatory Commission via letter DP-537 from F.M. Stern to Frank Schroeder dated December 2, 1974 This system was applied in determining that the subject document herein are proprietary.

4. The information is being transmitted to the Commission in confidence under the provisions of 10 CFR 2.790 with the understanding that it is to be received in confidence by the Commission.

5. The information, to the best of my knowledge and belief, is not available in public sources, and any disclosure to third parties has been made pursuant to regulatory provisions or proprietary agreements which provide for maintenance of the information in confidence.

6. Public disclosure of the information is likely to cause substantial harm to the competitive position of Combustion Engineering because:

a. A similar product is manufactured and sold by major pressurized water reactor competitors of Combustion Engineering.

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b. Development of this information by C-E required thousands of manhours of effort and hundreds of thousands of dollars. To the best of my knowledgeand belief a competitor would have to undergo similar expense in generating equivalent information.

c. In order to acquire such information, a competitor would also require considerable time and inconvenience related to the development of three-dimensional reactivity feedback credits.

d. The information required significant effort and expense to obtain

the licensing approvals necessary for application of the information.

Avoidance of this expense would decrease a competitor's cost in applying the information and marketing the product to which the information is applicable.

e. The information consists of the three-dimensional reactivity feedback credits, the application of which provides a competitive economic advantage. The availability of such information to competitors would enable them to modify their product to better compete with Combustion Engineering, take marketing or other actions to improve their product's position or impair the position of Combustion Engineering's product, and avoid developing similar data and analyses in support of their processes, methods or apparatus,

f. In pricing Combustion Engineering's products and services, significant research, development, engineering, analytical, manufacturing, licensing, quality assurance and other costs and expenses must be included.

The ability of Combustion Engineering's competitors 'to utilize such information without similar expenditure of resources may enable them to sell at prices reflecting significantly lower costs.

g. Use of the information by competitors in the international marketplace would increase their ability to market nuclear steam supply systems by reducing the costs associated with their technology development. In addition, disclosure would have an adverse economic impact on Combustion Engineering's potential for obtaining or maintaining foreign licensees.

Further the deponent sayeth not.

b A. E g heter _

Director Nuclear Licensing Sworn to before me this /0 day of O hl.} b Mt> CGOJU Notary Public U i

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. Enclosure 1-NP to LD-83-042 SYSTEM 80 CESSAR.FSAR DOCKETSTN55-470 RESPONSES TO QUESTIONS 440.5,10,11, and 12 ON SLB METHOD MAY, 1983 i

COMBUSTION ENGINEERING, INC.

NUCLEAR P.0WER SYSTEMS WINOSOR, CONNECTICUT 9

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LEGAL NOTICE t

THIS REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY COMBUSTION ENGINEERING, INC. NEITHER COMBUSTION ENGINEERING NOR ANY PERSON ACTING ON ITS BEHALF:

A. MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED INCLUDING THE WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTABILITY, WITH RESPECT TO THE ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATION CONTAINED IN THIS REPORT, OR THAT THE USE OF ANY INFORMATION, APPARATUS, METHOD, OR PROCESS DISOLOSED IN THIS REPORT MAY NOT INFRINGE PRIVATELY OWNED RIGHTS;OR B. ASSUMES ANY LIABILITIES WITH RESPECT TO THE USE OF, OR FOR DAMAGES RESULTING FROM THE USE OF, ANY INFORMATION, APPARATUS, METHOD OR PROCESS DISCLOSED IN THIS REPORT.

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Question 440.5 Page 15C-2 states: '

.... corresponding to end-of-cycle operation were used for the steam line breaks appearing in Section 15.1.5 to maximize post-trip reactivity insertion.

Calculational uncertainty in the PDQ-X calculation was accounted for through

. the use of conservative multipliers on the CESEC reactivity functions .

The CESEC three-dimensional reactivity feedback option gives the capability of including three-dimensional reactivity feedback effects associated 'ith w core inlet plane temperature distribution, stuck CEA, and changes in core power distribution. The 3-0 reactivity contribution is based on HERMITE (described in subsection 4.3.3.1.1) calculations, and is parameterized in CESEC as a function of core inlet plant temperature tilt (difference between hot and cold edge temperatures), core flow, and core fission power. This option was not used for the steam ine breaks presented in Section 15.1.5..."

Since the three-dimensional reactivity feedback option was not used in the CESSAR analyses described in Appendix 15C, show results that demonstrate the conservatism of the approach used relative to the three-dimensional results.

Provide the three-dimensional feedback reactivity table used as input to CESEC.

] Response:

1 A typical plot of reactivities versus time for a steam line break (SLB)

, analysis for a non-System 80 NSSS for which three-dimensional reactivity t

feedback was credited is shown in Figure 440.5-1. The three-dimensional reactivity feedback is always negative. - Therefore the approach used in the CESSAR SLB analyses is conservative relative to an approach which uses three-dimensional results. If three-dimensional reactivity feedback had been 3 credited for the System 80 SLB analyses the total reactivity values would have been more negative than the values presented in CESSAR.

Table 440.5-1 is the three-dimensional feedback reactivity table used as input to CESEC for a typical non-System 80 NSSS.

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TABLE 440.5-1 . . . . . _ _ _ _ _ _ _ _

__ . EXAMPLE 0FA__THREE DIMENSIONAL FEEDBACK REACTIVITY TABLE USED AS INPUT -

CESEC FOR NON-SYSTEM 80 NSSS

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Question 440.10 Section 15C.3.3.2 (page 15C-6) of the CESSAR FSAR states:

...For System 80 this most adverse state has been found to be the maximum core power, most positive ASI, minimum core flowrate, maximum pressurizer water level, maximum core inlet coolant temperature, maximum reactor coolant system pressure, and maximum water level in the affected steam generator with the water level in the unaffected steam generator at the maximum value which can exist initially and still result in emergency feedwater actuation at the time of main steam isolation valve closure (i.e., the transient time of minimum level)..."

Parametric analyses have not been submitted to substantiate the limiting conditions outlined above.' Provide parameteric results of minimum DNBR versus these various parameters to demonstrate that the most adverse state has in fact been determined.

Response

Parametric analyses have been performed to determine the sensitivity of minimum post-trip CHFR (DNBR) to each of the initial conditions described in Section 15C.3.3.2 of the CESSAR FSAR. The results of this study are presented in Table 440.10-1 in terms of the rate of change of the minimum post-trip CHFR with change in the initial value of each parameter, xj, with all other parameters held constant.

The values in Table 440.10-1 represent results of variations from the initial conditions for the most limiting steam line break (SLB) of the CESSAR FSAR.

This is the large steam line break during full power operation with concurrent loss of offsite power (Case 1 of Section 15.1.5). The initial conditions for this case are listed in Table 15.1.5-6 of the CESSAR FSAR.

The signs on (BCHFR/3xq) for xj being initial reactor coolant system pressure, initial pressurizer water volume, and ASI are such that the extrema of these values used for the analyses presented in the CESSAR FSAR Section 15.1.5 do not produce a value of minimum CHFR which is quite as low as might have been calculated had other values of these parameters been used. However for these parameters is such that the had magnitude of the value the opposite extrema been used of (BCHFR/3xj)l for al of these parameters the resultant minimum CHFR would have been well within acceptable limits. In the case of the initial pressurizer water volume and initial reactor coolant system pressure, the extrema chosen for the analyses presented in Section 15.1 of the CESSAR FSAR were chosen to delay and impede safety injection flow. However, due to conservatisms in the choice of other parameters, safety injection (SI)

. boron does not reach the reactor core until after the time of minimum post-trip CHFR. As a result phenomena, which are of second order when SI boron is important to the reactivity balance at the time of minimum CHFR, cause the reversal of the sign of ( 3 CHFR/3xj).

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TABLE 440.10-1 RATE OF CHANGE OF MINIMUM POST-TRIP CHFR (DN8R) WITH CHANGE IN INITIAL CONDITIONS FOR LARGE SLB DURING FULL POWER OPERATION WITH CONCURRENT LOSS OF OFFSITE POWER i Initial Condition, Xj (a CHFR/3Xj)Xj, j = 1, 2,.. 8, j / i / Units l Core Power -0.20 /%

2 ASI +0.50 / ASI UNI 3 Core Flowrate +0 23

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4 Pressurizer Water Level +8.8 X 10-3 /%

5 Core Inlet Temperature -1.3 /*F 6 Reactor Coolant Pressure +3.7 X 10-3 / psia 7 Affected Steam Generator Water Mass -

3.3 X 10-4 /lbm 8 Unaffected Steam Generator Water Mass -1.6 X 10-5 /lbm 9

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Qu2stion 440.11 Section 15C.3.3.3 (Amendment 7 of the CESSAR FSAR) outlines several assumptions

. (a, thru j) utilized in conservatively predicting the consequences of a postulated steam line break. Provide the sensitivity of each parameter to minimum DNBR.

In addition, specifically referring to assumption g), "As the MSIVs close steam

. bicwdown from the unaffected steam generator terminates..." Steam line pressure equalization lines may exist in the balance of plant (BOP) design such that MSIV closure may not terminate steam blowdown from the unaffected steam generator. Include this possibility in the parametric study of assumption g).

Finally regarding assumption j), show the effect of various inlet mixing ratios and the effect of outlet mixing (upper plenum) on the inlet mixing models and the overall parametric effect on minimum DNBR versus time.

Response

Parametric analyses have been performed to determine the sensitivity of minimum post-trip CHFR (DNBR) to each of the parameters listed in Section 15C.3.3.3, Amendment 7, of the CESSAR FSAR (assumptions a through j), where applicable.

Except as noted below, the results of this study are presented in Table 440.11-1 in terms of the rate of change of the minimum post-trip CHFR with change in the initial value of each parameter, xj, with all other parameters held constant. The values in Table 440.11-1 represent the results of variations from the analysis assumptions used for the most limiting steam line break (SLB) of the CESSAR FSAR (i.e., Case 1 of Section 15.1.5: large SLB during full power operation with concurrent loss of offsite power).

Note that, with respect to the question referring to assumption (g), the System 80 80P interface requirements allow no steam flow paths upstream of the MSIVs which are not isolated on MSIS. See for example Item M.11 of Section 5.1.4 of the CESSAR FSAR.

The sensitivity of minimum post-trip CHFR to certain of the parameters in the list (a through j) of Section 15C.3.3.3 of the CESSAR FSAR are not included in Table 440.11-1 for the following reasons:

1 Assumption (c): Sensitivity to moisture carryover cannot be expressed in the t form presented in Table 440.11-1. The results presented in the FSAR assume no moisture carryover. For comparison the most limiting steam line break case of the CESSAR FSAR (Case 1 of Section 15.1.5) was repeated with a moisture l '

carryover function which yielded a blowdown quality of 1.0 (pure saturated

vapor) at full power design steam flow rate and 0.5 at the maximum blowdown flow rate. The minimum post-trip CHFR for this case was more than 5 CHFR units greater than that for the comparable case in the FSAR (Case 1 of Section 15.1.5).

i l Assumption (f): The sensitivity of minimum post-trip CHFR to boron reactivity cannot be determined for the SLB cases of the FSAR. Due to the choice of conservatisms in the other parameters, safety injection (SI) boron does not reach the reactor core until after the time of minimum post-trip CHFR for the

cases initiated from full power. For cases initiated from zero power the post-trip fission power is too small to yield meaningful CHFR calculations. However 1

the sensitivity of rr.aximum post-trip reactivity to boron reactivity can be calculated for cases initiated from zero power, since SI boron does reach the core prior to the time of maximum post-trip reactivity for these cases. The change in maximum post-trip reactivity per percent change in the slope of the boron reactivity versus boron concentration function is -0.00013 ao /% for the most limiting zero power SLB of the CESSAR FSAR (Case 4 of Section 15.1.5).

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TABLE 440.11-1

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RATE OF CHANGE OF MINIMUM POST-TRIP CHFR (DNBR) WITH CHANGE IN PARAMETRIC ASSUMPTIONS FOR LARGE SLB

, DURING FULL POWER OPERATION WITH CONCURRENT LOSS OF 0FFSITE POWER Assumption of Sectica 15C.3.3.3 i X

$ (a CHFR) , j = 1, 2,.. 8 Units aX4 Xj j/i a 1 CEA Worth +20 /%ac b, d 2 Moderator reactivity -1.2

• e 3 Doppler reactivity -0.18

• g 4 Break area -1.4 **

h 5 Heat transfer area in the RV upper head +0.002 **

i i 6 Heat transfer area in the RCS, outside the +0.068 **

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upper head j 7 Inlet mixing +0.16 ***

j 8 Outlet mixing +0.17 per percent increase in slope of function

• • per percent increase in area l

per percent increase in mixing

Ouestion 440.12 Page 15.1-4 of Amendment 7 to the. CESSAR FSAR states that the consequences of all small steam line breaks (fraction of fuel rods predicted to experience DNBR) is the same as for the 1.0 square foot break analyzed. This is attributed to the core protection calculators. Provide greater details as to the reason for the insensitivity of minimum DNBR to break sizes in the small break regime.

Provide sensitivity analyses of minimum DNBR versus break size in the small steam line braak regime for the CESSAR NSSS design.

Since Appendix 15C is intended to be a documentation of C-E's steam line break methodology for generic application, provide a similar break spectrum sensitivity for typical C-E NSSS design without core protection calculators.

Response

Values of the minimum DNBR versus total steam line break (SLB) flow area (break area plus effective turbine ficw area) are presented in Figure 440.12-1. This figure includes curves of DNBR versus flow area both for System 80, with reactor trip on projected low DNBR as determined by the core protection calculators (CPCs), and for a typical C-E NSSS design without CPCs. For System 80 the minimum DNBR occurs at the maximum flow area. For the plants without CPCs, the minimum DNBR occurs at a flow area less than the maximum.

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1 COMPARISON.0F MINIMUM TRANSIENT Di:BR VS.

STEAMLINE BREAK FLOW AREA FOR SYSTEM 30 & NON-CPC TRIP NSSS l