ML20199B907
| ML20199B907 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 11/12/1997 |
| From: | Mcintyre B WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | Quay T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML19313D078 | List: |
| References | |
| AW-97-1186, NUDOCS 9711190149 | |
| Download: ML20199B907 (61) | |
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\\J Westinghouse Energy Systems p% 345,p,,, g 3 m 333
, Electric Corporation.
3w.97.ll86 -
November 12,1997 Document Control Desk U.S. Nuclear Regulatory Commission
" Washington, DC 20555 ATTENTION:
MR. T. R. QUAY APPLICATION FOR WITilllOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE
- SUlHECT:
RESPONSE TO REQUESTS FOR ADDITIONAL INFORMITAON ON AP600 NOTRUMP VERIFICATION AND VALIDATION (RAI 440.721d & 440.721g)
Dear Mr. Quay:
The application for withholding is submitted by Westinghouse Electric Corporation (" Westinghouse")
pursuant to the provisions of paragraph (b)(1) of Section 2.790 of the Commission's regulations. It contains commercial strategic information proprietary to Westinghouse and customarily held in confidence.
3 I
The proprietary material for which withholding is being requested is identified in the proprietary version of the subject report, in conformance with 10CFR Section 2.790, Affidavit AW-97-Il86 accompanies this application for withholding setting forth the basis on which the identified proprietary information may be withheld from public disclosure.
Accordingly, it is respectfully requested that the subject information which is proprietary to Westing'nouse be withheld from public disclosure in accordance with 10CFR Section 2.790 of the Commission's regulations.
Correspondence with respect to this application for withholdiag or the accompanying affidavit should reference AW-971186 and should be addressed to the undersigned.
I Very truly yours, 1
13rian A. McIntyre, tanager Advanced Plant Safety'and Licensing;.
jml Jcc:
Kevin llohrer -
NRC OWFN - MS 12E20 kDk l
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lAFFIDAVIT
~ COMMONWEALTil OF PENNSYLVANIA:
e ss COUNTY OF ALLEGilENY:
Before me, the undersigned authority, personally appeared Brian A. McIntyre, who, being by me duly sworn according to law, depows and says that he is authorized to execute this Afridavit on behalf of Westinghouse Electric Corporation (" Westinghouse") and that the averments of fact set forth in this Af11 davit are true and correct to the best of his knowledge, information, and belief:
d ~ A pr - ~
r-Brian A. McIntyre, Manager Advanced Plant Safety and Licensing Sworn to and subscribed before me this
/2' day-of
,1997 4
-[
Notary Public NotarialSeal -
Rose Marte Payne. Notary Ptrblic Monroevdio Doro, Allectany County
- My Commission Expires Nov 4,2000
- Dmber. Pennsylvania Assocuuonof Notanes 5
b 4-L m
o
AW.97 ii86 (1)
I am Manager, Advanced Plant Safety And Licensing, in the New Plant Projects Division, of the Westinghouse Electric Corporation and as such, I have been specincally delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plant licensing and rulemaking proceedings, and am authorized to apply for its withholding on behalf of the Westinghouse Energy Systems Ilusiness Unit.
(2)
I am making this Af0 davit in conformance with the provisions of 10CFR Section 2.790 of the Commission's regulations and in conjunction with the Westinghouse epplication for withholding accompanying this Affidavit.
-(3)
I have personal knowledge of the criteria and procedures utilized by the Westinghouse Energy Systems ilusiness Unit in designating infonnation as a trade secret, privileged or as conHdential commercial or Snancial information.
(4)
Pursuant to the provisions of paragraph (b)(4) of Section 2.790 of the Commission's reguiations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.
(i)
The information sought to be withheld from public disclosure is owned and has been held in con 0dence by Westinghouse.
(ii)
The infonnation is of a type customarily held in con 0dence by Westinghouse and not customarily disclosed to the public. Westinghouse has a rational basis for determining the types of information customarily held in con &dence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in confidence. The application of that system and the substance of that system constitutes Westinghouse policy and provides the rational basis required.
Under that system, information is held in con 0dence if it falls in ene or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:
i um wet
AW-97-1186 i
(a)
. The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other compenies.
(b)
It consists of supporting data, including tem data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage, e.g., by optimization or improved marketability.
(c)
Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar proJuet.
(d)
It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or rnppliers.
(e)
It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercia' value to Westinghouse, (f)
It contains patentable ideas, for which patent protection may be desirable.
There are sound policy reasons behind the Westinghouse system which include the following:
(a)
The use or such information by Westinghouse gives Westinghouse a competitive advantage over its competitors, it is, therefore, withheld from disclosure to protect the Westinghouse competitive position.
(b)
It is information which is marketable in many ways. 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.
miwyr
AW 97-1I86 (c)
Use by our competitor would put Westinghouw at a competitive 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 competitors acquire components of proprietary information, any one component may be the key to the entire puzzle, thereby depriving Westinghouse of a competitive advantage.
(e)
Unrestricted disclosure would jeopardize the position of prominence of Westinghouse in the world market, and thereby give a market advantage to the competition of 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.
(iii)
The information is being transmitted to the Commission in confidence and, under the provisions of 10CFR Section 2.790, it is to be received in confidence by the Commission.
(iv)
The information sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method to the best of our knowledge and belief.
(v)
Enclosed is Letter DCP/NRCll31 (NSD-NRC-97-5432), November 12,1997, being transmitted by Westinghouse Electric Corporation (W) letter and Application for Withholding Proprietary Information from Public Disclosure, Brian A. McIntyre @),
i to Mr. T. R. Quay, Office of NRR. The proprietary information as submitted for use by Westinghouse Electric Corporation is in response to questions concerning the AP600 plant and the anociated design certification application and is expected to be applicable in other licensee submittals in response to certain NRC requirements for l
um.,e
AW.97-Il86 justification of licensing advanced nuclear power plant designs.
This information is part of that which wih vble Westinghouse to:
(a)
Demonstrate the design and safety of the AP600 Passive Safety Systems.
(b)
Establish applicable verification testing methods.
(c)
Design Advanced Nuclear Power Plants that meet NRC requirements.
(d)
Establish technical and licensing approaches for the AP600 that will ultimately result in a certified design.
(e)
Assist customers in obtaining NRC approval for future plants.
Further this information has substantial commercial value as follows:
(a)
Westinghouse plans to sell the use of similar information to its customers foi 1
purposes of meeting NRC requirements for advanced plant licenses.
4 (b)
Westinghouse can sell support and defense of the technology to its customers in the licensing process.
Public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar advanced nuclear power designs and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.
mu..pr
AW.97-1186
.s The development of the technology described in part by the information is the result of '
applying the results of_ many years of experience in an intensive Westinghouse effort
. and the expenditure of a considerable sum of money.
j
-i in order for competitors of Westinghouse.to duplicate thi: information, similar
-}
technical programs would have to be performed and a significant manpower effort, _
[
having the requisite talent and experience, would have to be expended for developing
- analytical methods and receiving NRC approval for those methods.
~ Further the deponent sayeth not.
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ENCLOSURE 2 TO DCP/NRC1131 RAI 440.721(d)
RAI 440,721(g)
NON PROPRIETARY 5
HAk opt
lite RE49tST FM AB8tilnAL lilFMIRAT1H Question 440,721(d)
Provide an explanation for NOTRUMP's misprediction when compared to the OSU test results of DVI line breaks.
Response
The mitpredictions observed for the DVI line breaks are higher core and downcomer collapsed liquid levels, after ADS l 3 opened, for OSU test SBl2 (Double Ended DVI Line Break). For example, the levels are overpredicted beginning at [
] " seconds (Figures 8.3.414 and 8.3.418 of Reference 440.721(d)-1). In addition, the mass discharged from ADS 13 is underpredicted (Figure 8.3.4 27 of Reference 440.721(d)-1), while the mass discharged from the broken DVI line is overpredicted (Figure 8.3.4 29 of Reference 440.721(d) 1). He time when the misprediction occurs is shortly after ADS 1 opens, and extends to about [
]" seconds. After this time, the core collapsed level is in good agreement with the test data, while the downcomer level is slightly higher than the test data.
During the review of the information related to this RAI, it was discovered thet incorrect values were utilized for the ADS 13 valve areas in the NOTRUMP simulation described in Reference 440,721(d)-1. The revised results, while improved, still exhibit similar behavior to that observed in Reference 440.721(d) 1. The revised results will be provided in Revision 3 of the aforementioned reference. The test and the revised prediction are examined in more detail below:
Review of Test Data:
Test data can be utilized to compare what is hsppening in the tests relative to the NOTRUMP simulation. Figure 440.721(d) l shows the collapsed liquid across several spans in the downcomer.
These spans are shown in Figure 440.721(d)-2. The collapsed liquid level in span I drops to the top of span 2, then the level in span 2 begins to drop, while all lower spans remain liquid solid. This is indicative of the draining of a single phase liquid layer. At about [
)" seconds, spans 3 through 5 show signs of voiding. This is an indication that a two phase mixture has formed (if there were no voiding in the downcomer liquid, the collapsed liquid level in span 4 would remain at 45 inches until the liquid level in span 3 dropped to [
]" inches). At [
l" seconds, the ADS 2 valves open and additional veiding of he two phase mixture occurs. Dere is also an inJication of two phase level swell, in that the mixtur: level enters span 2 at about [
}" seconds, which corresponds to the ADS 3 actuation time.
Figures 440.721(d)-3 to 9 show the downcomer Guid temperature from the top to the bottom, compeed to the saturation temperatures at the top ard bottom of the downcomer. Two locations are shown; one below the intact DVI, and one below the broken DVI. It can be seen that there is a distinct two dimensional temperature pattern, with subcooled water penetrating the intact side of the downcomer, but not compktely mixing with the fluid on the broken side. Figure 440.721(d)-3 also shows that the Guid in the top of the downcomer region is superheated; this is discussed later.
![U N1
~
P llRC RE40EST F08 ASSITl4NAL IWF42AT10N Figures 440.721(d)-10 through 12 present additional information related to the mptured DVI Cold Leg Balance Line (CLBL)/ cold leg which funher suppons the eAistence of two dimensional downcomer behavior, Figure 440 72)(d)-10 indicates a two phase mixture level swell is observed in the downcomer at th. cold leg connection elevation between [
]"and [
]" seconds. Subsequently, this level swell is observed to propagate into the ruptured DVI line CLBL (Figures 440.721(d)-il and
- 12) which affects the core /downcomer level behavior; this is discussed later.
From these figures, it is concluded that portions of the downcomer Guid remain two-phase, even while subcooled water is being injected via the intact DVI line. The two phase mixture prevents additional liquid from being stared in the downcomer, and swells to the broken DVI line CLBL, such that vapor How out the DVI side of the break is suppressed.
NOTRUhfP Predictions:
The next series of figures examine the NOTRUhtP prediction, and compare various quantities with test quantities. Figure 440.721(d)-13 shows the downcomer, lower plenum, and bottom of core Guid node temperatures. The downcomer Guid becomes subcooled when ADS Stage 2 opens at -140 seconds.
Since the NOTRUh1P downcomer Huid node is one-dimensional, it cannot simulate the two dimensional temperatures, levels and flow pattems observed in the test. As a result, more mass is stored in the downcomer and core regions.
Figure 440.721(d)-14 shows the pressurizer two-phase mixture level predicted by NOTRUh1P. The mixture level reaches the top of the pressurizer following ADS Stage 3 actuation, so two-phase flow is calculated out of the ADS l-3 paths (Figure 440.721(d)-15). The predicted two phase level remains at the top of the pressurizer until the activation of ADS Stage 4, at which time the NOTRUh1P simulation and test data diverge. Detalk regarding the explanation of the pressurizer drain mispredictions are found in the response to RAI.440.721(f).
It should be noted that the ADS l-3 flow measurement instrumentation is located downstream of the ADS 1-3 separator tank in the test facility. The Cows are separated, measured, re-combined and subequently discharged into the IRWST tank. The NOTRUh1P simulation of the ADS Dow paths do not model this level of detail. The NOTRUh1P model simply consists of three separate Dow paths, each simulating an ADS valve stage, which discharge directly into the IRWST tank. As such, the measured and predicted ADS 1-3 Dow quantities are not identically comparable. The following discussion attempts to consider the effect of these differences.
Figure 440.721(d) 16 shows the measured vapor and liquid How via the ADS Stage 1-3 valves. The liquid How measurement indicates a low, intermittent flow of liquid following ADS Stage I actuation.
It is indicative of either a two-phase mixture level which did not reach the top of the pressurizer, but where there was entrainment above the mixture level, or a two-phase mixture level which reached the top of the pressurizer for intermittent time periods. Based on the collapsed pressurizer level instrument reading off span low (i.e. indicating an empty pressurizer), the initial liquid discharge measured, 444.72 Mil -2 3 Westinghouse
A following dDS I opening, may not be indicative of conditions leaving the ADS valves (Figure 440.721(d)-17). Also, the measured liquid discharge, following ADS Stage 2 opening at [
]"
seconds, is likely the result of ADS vapor discharge displacing ADS separator liquid which is subsequently measured as ADS liquid discharge, Figure 440.721(d)-18 compares the separator liquid level and measured ADS liquid now. There is a sudden drop in leve at [
]" seconds and corresponding increase in measured ADS liquid now. To determine the impact of these observed test facility phenomena on the NOTRUMP comparison, the measured liquid now prior to ADS-3 actuation was eliminated. A comparison plot of the integrated raw test data, adjusted test data, and the NOTRUMP predicted ADS 13 liquid discharge is presented in Figure 440.721(d)-19. As can be observed, the comparison between the NOTRUMP simulation and the test data are bet'er matched following the adjustment. While some entrainment is expected to occur during this period, it is not expected to be of the magnitude measured in the test facility, Based on the amount of liquid entrainment, the predicted vapor now into the pressurizer and ADS l-3 is somewhat lower in the NOTRUMP simulation when compared to the test. Note that although a comparison between the predicted and measured vapor Dows supports this conclusion, the degree of difference may be misleading because the measured vapor now includes liquid which has flashed after passing through the ADS valves into the separator.
Figure 440.721(d)-20 compares the total predicted vapor flow from the core with the predicted vapor flow into the pressuriter surge line. Evidently, a large portion of the vapor generated in the core is bypassing the pressurizer / ADS path. Figure 440.721(d)-21 compares the core now with the total now from the downhill side (i.e. SG cold side tubes) of both steam generators. This shows a signincant portion of the generated vapor is nowing tt
.gh the hot legs, steam generators, through the cold legs to the ruptured DVI paths (either via the mpmred DVI CLBL or downcomer). Figure 440.721(d)-22 compares the steam generator outlet and broken DVI line (vessel side) vapor Dows and confirms that a majonty of the vapor is being discharged via this path. Since the SG outlet now is slightly higher, this 6gure also indicates that vapor is also being discharged through another location. Figure 440.721(d)-23 presents the NOTRUMP predicted vapor discharge from the DVI side of the DVI line break which represents the additional steam vent path. Figure 440.721(d)-12 indicates the test undergoes a liquid in-surge into the ruptured DVI line CLBL thereby preventing vapor venting via this path. This is a result of the two-dimensional behavior occurring in the test facility downcomer region, which can not be predicted to occur with the NOTRUMP model. This lack of two dimensional capability results in the diversion of core generated vapor away from the ADS Stage 1-3 flow paths.
Con 6miation that a similar vapor now pattems exists in the test, with the exception of the previously mentioned DVI side vapor venting, can be obtained by comparing the measured and predicted fluid temperatures at the top of the dowucomer, Figure 440.721(d)-3 and 24. In both cases, the vapor at the top of the downcomer is superheated. This can only occur if the vapor has first passed through the steam generator tubes.
Figures 440.721(d)-25 and 26 compare the predicted break vapor and liquid Hows with measured test data. tiefore [
]" seconds, there is measured vapor flow, even though the DVI line is covered and the Guid is subcooled. As previously noted, this is due to flashing of the fluid as it enters the separator
[ Westingt10US8
b I
NRC RE40tST 848 AB0mtHAL INFORMATitN which is near atmospheric pressure (the Ogures show the NOTRUh1P predicted Dows as they enter the broken DVI line, prior to flashing). The measured vapor now prior to [
]" seconds is seen to nearly account for the difference between the measured and predictcJ liquid nows prbr to [
]" secords (Figure 440.721(d)-25). After about 200 seconds, predicted vapor dow is higher out the DVI line and somewhat lower out the ADS l 3 line (compare Figures 440.721(d)-15 and 16).
The above discussions demonstrate that:
- 1. A two dimensional temperature / level pattem forms in the downcomer, allowing portions to n main saturated and flash when ADS l 3 open. Because of the Dashint, and level swell occurring L. the downcomer fluid in the test, less mass is stored in the downcomer.
- 2. hiuch of the vapor generated in the core exits through the broken DVI line for this break. No vapor venting is observed via the DVI side of the DVI line break as a result of the two dimensional downcuner behavior whereas the NOTRUhiP model exhibits vapor venting via this path.
- 3. The one-dimensional downcomer model in NOTRUh1P does not predict the two-dimensional temperature pattern. Instead, the downcomer Guid becomes subcooled. This additional mass then distributes into the core, leading to overprediction in the collapsed liquid level. In addition, less vapor is generated in the core and subsequently Dows out ADS l-3.
==
Conclusion:==
For DVI line breaks, the same complex temperature and How patterns as observed in the test can be expected to occur in the AP600 This means that NOTRUh1P overpredicts the vessel mass for some time period after ADS 13 opens. However, once the ADS 1-3 blowdown has been completed, the core mass is predicted well in both SPES and OSU, such that when intact IRWST injection is initiated, the correct amount of mass must be replenished by the IRWST. Therefore, the misprediction of core /downcomer mass during the ADS 13 blowdown period is not a serious denciency. In addition, application of the IRWST tevel penalty derived in response to RAI 440.721(g), will introduce additional conservatism into the vessel mass prediction.
448,H1(d) 4 3 Westinghouse
NSB r.iit9EST F98 A99ffituAL lilf9til4Titil i
References:
440.721(d) 1 "NOTRUMP Final Validation Report for AP600", WCAP 14807, Revision 2. June 1997 440,721(d) 2 "AP600 Low-Pressure Integral Systems Test At OSU: Test Analysis Report "
WCAP 14292, September 1995.
440.721(d) 3 "AP600 Low Pressure Integral Systems Test As OSU: Final Data Report," WCAP, May 1995.
SSAR Revisions: None T Westinghouse
L: E a,c A
d 4
4 Figure 440,721(d)-1 OSU Test SB12 Downcomer Collapsed Level!.
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_OSU Test SBl2 Downcomer Fluid Temperature @ 67.33 Inches 448.72M W T Westinghouse
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7g a.c Figure 440.721(d) 9 OSU Test SB12 Downcomer Fluid Temperaturt @ 20.73 Inches 448.71118) W g
m 1.C Figure 440.721(d) 10 OSU Test SBl2 Collapsed Liquid Level At Cold Leg Elevations 1
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Figure 440.721(d) il OSU Test SBl2 Temperature Distnbution 44Mf1(d) W g
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.,$g.01 y
100 200 300 400 Time (S)
Figure 440.721(d) 23 NOTRUMP Break (DV1 Side) Vapor Discharge
. ansi n g m,,,,
g mminom m memum wee m n 0.SU
- Sb12, DEDVI Break VesseI Temperotures fWFN 6
0 0
004E N00t-4 WestyRt
TVFN 1
0 0
00*NCoute vap04 ttu 450
'g
~\\
400 s
~
1 I
n s
6 i
v i
350
' i.
e 1%
6.
a s,
\\ \\
A
,I O
s,.
w 6
a 300 d
b ls
+
i i
li 250
..ig a
i l
~
g x1A{
+
200 V
100 290 300 400 tim.
(e)
Figure 440.721(dF24 NOTRUMP SB12 Simulation Downcomer Temperatures
,Y N
irm 1138 ItWIST Pet Atemenallargegangg m._
4.C
~
I uit 440.721(d) 25 Vessel Side Break Vapor Flow Compwison YN
t 338184818T fet 400meau 1er0054fl0E
'i" t
_ a.c Figure 440.721(d)-26 Vesul Side Break Liquid Flow Compuixm YO i
8 eL_
-,--.a m
6 g
,+
gA.
y%u a,,,,
a__L-.g;1 A,
_y,,_
w m,.
g,m,J.,,,-
2_ _ _
,.-+t.J-4.-.,_
E.h--1,-
f NRC REQUEST FOR ADDITIONALINFORMATION
- g nnv Question 440.721(g):
Related to(O abose, Westinghouse is proposing to apply a penalty in IRWST lesel. Proside a detailed esplanation of how the penalty is determined via scaling from the OSU test data to the AP600. Justify w hy this is conservatise.
Response
In the response to RAI 440.721(c), the pressunter re61ling phase u as described, and in the response to RAI 440.721(f), the pressuriter draining process was desenbed. nc 6l ling process was shown to result from the level swellin the system due to the vapor flow through ADSl.3 and the resulting system depressurization De Jraining process was shown to be limited by vapor still flowing through ADS t.3 after the system had fully depressurited and ADS 4 had opened.
It w as shown in the response to RAI 440.721(f) that the residual mass left in the pressuriter contributed to a higher downcomer pressure late in the transier1 Dis higher pressure effectively reduced the net hedrostatic driving head available for the IRWST. and caused a delay in the time at which IRWST water began to inject. In NOUtVMP, the draining of the pressuriter occurred more quickly, tesulting in an earlier and a higher predicted IRWST injection.
De re6ll phase is important because this will determine how much mass must be drained from the pressunzer. The draining phase is important because this will determine the time it takes to drain th: pressunter. Each phase is discussed below, Grst to establish whether the OSU test facility is correctly or conservatively scaied, and then to establish an equivalent IRWST level reduction for use in the AP600 calculation to account for the observed NOTRUMP de6ciencies.
hfilhna chase; just prior to ADSI.), the system has partially drained by mass loss through the break. De pressurire' is empty of water. The CMT has been draining, Alling the downcomer, lower plenum, and part of the core with cooler water.
Abose this cool water is a warmer layer of saturated liquid and two phase misture, consisting mostly of the onginal pnmary side inventory.
Ilecause the level swcil is controlled primanly by vapor Gow and void fraction, these variables need to be scaled correctly in the test facility. Since steam generation rate is imponant, OSU will exhibit fewer scaling distortions during this penod than SPES because the energy contribution from heated structures has been substantially reduced.
On the other hand, OSU is a reduced pressure and reduced height test facility, so other scaling issues will become important.
Reference 440 721(gb3 provides a detailed scaling analysis of the OSU and SPES test facihties. De OSU test facihty ADS valves were sired to produce the appropnate response, taking into account the lower initial pressure of OSU. It was concluded that the OSU test was more appropriate than the SPES 2 test for assessing the effects of pressu irer renti because OSU was not distorted by excess heat release from metal structures.
De test results show that any distortion in level swell results in a conservative estimate of the pressurizer refill relatise to AP600. His is because in most of the OSU tests, the pressuriter nearly 611s completely with water. If the test facihty is accurately scaled, then this is an accurate depiction of the behavior of AP600. If the test facility is not accurately scaled, then from the point of view of pressunter re611 and subsequent draining, the OSU test is consenative, since it results in the highest possible refill of the pressunter.
W Wesdnghouse 440.721(g) 1
o e
NRC REQUEST FOR ADDitlONAL INFORMAtlON p
Drainine chase:
Emandnation of the collapsed liquid leselin the pressurizer shows that the drain rate for most of the smaller breaks is much slow sr than dra.ning of the pressurtz.it limited only by the surge hne resistance. It w as concluded that the drain rate is being limited ty vapor How into the pressurizer (see response to RAI 440.721(f)). Because the liquid draining from the pressunies, surge line, and hot leg is interacting closely with the vapor through interfacial drag, an increase in tb pressure of the vapor occurs. Since the onset of IRWST draining is controlled by the downcomer pressure, this pre nunration delays IRWST injection as previ >usly noted. It is expected that the same process will occur in the AP600, so account must be taken of the effect ofliquid holdup in the AP600 calculation. Because the ADS 4 valve is oveisized in the SPES test relative to AP600, it was again concluded that the OSU tests were more tppropriate for eaaniining this effect The effect of this liquid holdup in the OSU test will be scaled up to AP000 conditions using the following simple niodel.
Assume that the downcomer pressure at the location of the DVI line is approximately equal to the system pressure.
h
- Assume that the system pressure is controlled by the resistance which the ADS vent valves present to t e vapor generatcd in the core, and an " effective" height of liquid held up by the vapor in volumes above the DVI injection point. De system pressu:e P is tnen related to core vapor now W. by:
l44(a*'- P,) = K 1 (d)i + p,h g W
44o.721<g). t ge
'
- Pe \\ A/
where P. is (1.4 IRWST tank pressure (15.:' psia), and h' is an effective liquid height. To determine if this is a reasonable mool for the system preuure late in the transient, the effective height was calculated from known test conditions for se veral of the OSU tests. De various q"antities needed to calcriate h' are listed below:
QUANTITY VALUE BASIS P
Measured test data (psia)
Instrument CIT ll t is located at top of DC P.
.Wasured test data Instrument CIT 701 is located at top of IRWST 0.045 lb/ft' Vapor density at 18 psia (typical system pressure) p, 60 lb/ft' Liquid density at 18 psia pi K
1"(all tests er DEDVI)
Composite loss coef 0cient thru ADSI.3, ADS 4 1"(JEDVI) 3 A
]" ft (all tests ca. DEDVI) Total Cow area thru ADS t.), ADS 4 l" rt We Calculated from test data ('b/s)
RPVRXV (eg., Fig. 5.3.2 55. ref 440.721(g) 2) t M0.721($2 IN
NRC REQUEST FOR ADDfTIONAL INFORMATION Using the abose values results in the following formula for h':
I 440,121(g1-2 De above equauon will be used for all the tests escept Sbl2 (DEDVI). For Sbl2, the second term value is [
}".
Figures 440.721(g),1 to 6 show the calculated effective liquid height h' for OSU tests Sbl8, Sbl3, Sbl2,5b09, Sbl0, and Sbl4, using Equeuon 440.721(g>2. Also shown ot. the plots is the ume at which the IRWST begins to infect. Early in the transient, the system is still depressunting and the steam generation rate is underestimated because fluhing is ignored in Equation 440.721(g) 2 (for esample, at 1000 seconds in Figure 440.721(gFI). On the average for all the tests, howevrr, the effective liquid height settles to approsimately $ feet after the system has depressunted and !RWST has begun.
De same approach can be used to calculate the effecuve hquid height present in the NOTRUMP predictions of the above tests. In this case, ation 440.721( F2 is again used, but P and W are NOT1tUMP calculated values.
Dese results are shown m gutes 440.721( F7 to 12. It can be seen that the effecuve liquid height is correctly predseted at the ume IRWST injecuon begms, and then is underpredicted (for esample, aher 1600 seconds in Figure-440.721(gF7). The time at which the predicted effecuve level drops below the test value usual comcides with the ume at which the pressunter is predicted to empty As pomted out in the response to RAI 440. 21(f), the result of 8
the lower effective liquid levelis a reduced downcomer pressure, w hich then causes the IRWST flow to be overpredicted. With the escepuon of test Sbl2 (DVIline break) and Sbl4 (inadvertent ADS), the effective level drops to about 2 feet (for esample, Figure 440.721(gb7 after 1600 seconds) so the estent to *hich the effective hquid level is underpredicted dunns this ume is about 3 feet. In the prediction of tests Sbl2 and $ble, the effective level drops to near zero late in the transient, we. after conunuous IRWST injection has been established, in Test Sbl 2, the reason that the level is lower than in the other cases is partly because in the NOT1tUMP predicuon, much of the core steam is calculated to flow out of %h sides of the broken DVI line (see response to RA1440.721(d)).
Dese additional paths are not taken into account in Equauon 440.721(gb2. With a lower resistance to vapor now, the second term would be smaller and the effecove liquid height would be largee. In addition to these effects, there is also a mispredicuon of the downstream pressure of ADSI.3 as indicated in the response to RA! 440.721(d). In the Sbl2 test. somewhat less vapor was vented out the broken DVI, so the effect of ignonns this vent path would be smaller (since ignonng this vent path leads to a larger difference between test and predicuen, the approach is conservauve). In the $ble test, there is significantly more steam generated in the NOTRUMP prediction, tocause the core mlet subcooling is much lower (see Figun 8.3.7 42 in reference 440.721(g>2). In this case. Equeuon 440.721(g>2 adequately depicts the avatlable vent paths, since there is no break path, it is proposed to account for the underprediction of effective liquid level in NOTRUMP by reducing the level in the IRWST. De basis for correcung the calculation this way is given by the equations below, which desenbe the previous momentum balance and the flow equauon for the IRWST:
M0.721(g) 3
NitC ltteutST FOlt ADDlitONAL INFoltMATION
!f K*"
g,l44(P - P,) = P As,'os W,* + p,h'g K'#
W$ + Pi ing 44o. m ca>. 3 h
=-
i 2
29:Ani Wi = pi(h a - h')-
W,*
^"'
i i
2p; A,a 2p,,Alos i
where Km and Ain se the IRWST injection line resistance and area, and W e is LSe IRWS1 flowrate. This equation i
shows that the effective liquid height can be viewed as a reduction in the iRWST water level. Increasing the
- effective level by 3 feet in the NOTRUMP predictions by some means such as modifying the 00w models would bring the downcomerpressure up and the IRWST flow down the required amount to agree with the data. Based on Equation 440.721(gb3. an equivalent adjustment is to reduce the IRWST level by 3 ft. By inspection, for all cases, adding 3 feet to the predicted effective liquid height will result in a conservatively high downcomer pressure at the time ofIRWST injection. Figures 440.721(gbl3 to 16 compare the test equivalent height to the NOTRUMP prediction after adding 3 feet for selected tests (Sb9, Sbl0. Sbl2, Sbl4). In some cases, the adjusted effective liquid height falls below the test value late in the transient. However, this occurs well after the IRWST has begun to inject, in the lorig term cooling phase of the LOCA event. For all cases, the added 3 feet results in a higher downcomer pressure at the time IRWST injection begins which will delay IRWSTinjection and reduce its flow for the important period of time when the IRWST flow is not yet sufficient to make up the mass lost from the system. Since NOTRUMP is not used for AP600 SS/ It long term cooling calculations, this non conserva: ism late in the transient is considered to be unimportant.
In order to establish the value of h' and the necessary conection at the AP600 scale, take as the reference condition the point at w hich the IRWST flow is just'rero. From Equation 440.721(g)-3:
v 7
440.721(g) 4 T wesHnghouse
F NRC REQUEST FOR ADDITIONAL. INFORMATN)N pe s,,
r 2
Oc 3 (h a - h') = K ns 4
440.72itg>
4 f
A$os 2PtA8 y f,,
h t
where the core steam generation ra!J has been replaced by the core power Q, and the heat of vaporization hg.
The OSU facility scaling, and the values of some key parameters relative to AP600 are (Table 8.2 4. Reference 440.721(g).3):
QUANTITY OSU AP600 Power 1.0 96 0 l
Area 1.0 48.0 licight 1.0 4.0 K$ns i
1" 3.13 IWRST level (ft) 8 32 Taking the ratio of Equation 440.721(g)-4 canceling property terms which are assumed similar, we get:
(h g - h') ^" _ K <^$s" ' A ?ll * '960 '"
i
~
(hia-h')"'"
K $" < 48 Alll, < Q, '",
440.721(g)- 5 f 3.13' /96
7.6
=
=
(1.65n48s For an average effective liquid height of( ]" ft in OSU therefore, the following effective liquid height applies in AP600:
(h g - h') ^" = 7.6(h g - h') '"
i i
h'^" = 4hlg'" - 7.6(h a - h')"
i 440.721(g)- 6
= 7.6h *" - 3.6h '"
ig
= 9.2ft The effective liquid level correction should therefore be adjusted by:
&'A*=(9.2'ausu go,,,1,,3,,
(5s where Sh* is the incremental increase in effectise liquid height needed to produce agreement with the OSU data.
The adjustment of 3 feet in the OSU tests therefore translates to a value of 5.5 feet in the AP600 calculations. A level renalty of 6 feet is conservativelv neolied to the AP600 SSAR small break LOCA NOTRUMP calculat.47L MM M0.721(g) 5 W
4
'*z rwwe er-M P
w-reTPm T
m a
m.pr 67*i
NRC REGUEST FOR ADDmONAL INFORMAflON k
in one other important respect, reduction of the init;al IRWST level to correct for the NOTRUMP deficiencies is conservative because the effect is permanent, even after the pressunter has drained. In the AP600 calculation, additional conservati$e assumptions with regard to the core power as required by 10CFR50.46. Appendis K. result in substantially less liquid abose the core, w hich would cause the effective liquid les el to be reduced relative to the OSU test conditions.
References.
440.721(g).1 "NOTRUMP Final Vahdation Report for AP600". WCAP 14807. Revision 2.1997 440.721(g) 2 "APMX) Low Pressure integral Systems Test At OSU: Test Analysis Report". WCAP 14292.
SeptemNr 1995.
440.721(gp3 "AP600 Scaling and PIRT Closure Report". WCAP 14727. Revision 1.' July 1997.
E t
i r
.1-M0.721(g) 6 TN f
r c.,,.--,,,.-_my.
,i
i i
i NRC Mt00EST POR ADDITNH4ALINFORMATION f
t i
i i
i b
i
=
t t
5 e
f k
n Figure 440.721(g)-1 Effective liquid level above the DVI injection point for Test Sbl8.
i
+
T Westinstmse
- 440.72HW 7 i
I f
,c..
,,-w
.n,
y i-l I
=
[
I NRC MOUEST FOR ADOmONAL INFORMATION
+
i r
I i
i r
4,, C d
uses i
Figuce 440.721(g) 2 Effective liquid level above the DVI injection point for Test Sbl3 440,721(g) 4 -
W westinghouse i
i y
.c.n
-m.,.
3, e.-
,-,m.-,--..m.,,,---e--
y e
. =..
- _.. _. - _ - -. ~..-- - --
\\
l i
NRC REQUEST POR ADDITIONAL,INFORMATION f,
l.I <
[
A., '
h t
Figure 440.721(gb3 Effective liquid level above the DVI injection point for Test Sbl2, W Westingtoute M0.721(g) 9 t
1
?
NRC REQWST FOR ADDITIONAL INFORMATION wr ii
/1 i e
" 0 1
9 t
Figure 440.721(g) 4 Effective liquid level above the DVI injection point for Test Sb09.
440,721(g)-10 WN L
s e,-
_m..
_ a
..,y
..-y..
y v
w,
(-
NRC REQUEST FOR ADDITIONAL INFORMATION :
o.
p :p n.......
0 A#
+
i P
~
s
~ Figure 440.721(gb5 Effective liquid level above the DVI injection point for Test Sbl0.
T Westinghouse 440.721(g)-11 2
m,,---
+
-4
.rewn w
e- - -
NRC Rieugsf FOR AD0mONALINFORMATION i
r CLg G i
I Figure 440.721(g)-6 Effective liquid level above the DVI injection point for Test Sbl4.
440.721 @ -12 W w atnghouse
NRC REQUEST FOR ADDITIONALINFORMATION OSU Sb18 2
i nch Cold Leg Break v!*00049 1
0 0
00WNCOMER*PR($$UR[
O l
^
C I IS 5
l IRusr U
~ 10 V
=
E bU Y
ka 5
3, 7, g
,. r(
f fy 'fWW I
b 0
i 1000 1200 1400 1600 1800 2000 Time (S)
Figurt 440.721(g)-; Predicted (NOTRUMP' effective liquid level above the DV1 injection point for Test Sbl8.
O
NRC REQUEST FOR ADDITIONAL. INFORMATION V
OSU Sb13 2
inch DVI Line Break NOIRUMP Effeeteve neignt
_ 20 O
%,15 u*
t/W s ?
10 er
\\f h}* 'hpMle 4...'",'d b dl u@dMWh wiam.
5 Iw 1P'pung c-
,,,,. r v r ' i ' l v
0.
800 900 1000 1100 1200 1300 1400 1500 Time (S)
Figure 440.721(gF8. Predicted (NOTRUMP) effective liquid level above the DVI injection point for Test Sbl3.
440.721(g) 14 T Westinatiouse
NRC REQUEST FOR ADDITIONAL INFORMATION l
f',m w'
OSU Sb12 DEDVI Line Break NOTRUMP Eifec'sve neight
. 20 5
15
.?
- E 10 itWJ T V
5 0
0 200 400 600 800 1000 Time (S)
Figure 440.721(g)-9 Predicted (NOTRUMP) effective 'iquid leve above the DVI injection point for Test Sbl2.
T Westinghouse 440.721(g)-15
NRC REQUEST FOR ADDmONAL INFORMATION Pn..;
OSU Sb09 2
inch Balance Line Br.eck 97800052 1
0 0
00wNCOWER PRESSURE 20 E
w
//A/5 7*
J 1f
." 10 o
l lui g&a$lij;g I
5 l
i
)
}
1000 1200 1400 1600 1800 2000 Time (S) 1 Figure 440.721(g) !0 Predicted (NOTRUMP) effective liquid level above the DVI injection point for Test Sb09.
440.721(g)-16 IN
NRC REQUEST FOR ADDITIONAL.INFORMATION y
s,.,_
OSU Sb10 Double Ended Bolonce Line Break NOTRUuP Effeetive neight I AV) $ t"
)
1 lM[
g'd h
% 15 i
- E inke-[,
P 10 l' Iliqh lil' l
I I
U'h
~
5
'f }
?
1 j @ W "0
400 600 800 1000 1200 1400 1600 Iime (S) l Figure 440.721(g) 11 Predicted (NO1 RUMP) effective liquid level above the DVI injection point for Test Sb(0.
W Westinghouse 440.721(g) 17
e.
NRC REQUEST FOR ADDITIONAL INFORMATION p.
n,.....
OSU Sbl4 Inadvertent ADS A c t u a t ~i o n NOTRUMP EIfeetive neight 20
[
k 15
~
~
)
I f M S 7"*
o
- I O bl y
er h
2
~
3 llI"I) (
E 2
l anni i
400 600 800 1000 1200 1400 Time (s)
Figure 440.721(g) 12 Predicted (NOTRUMP) effective liquid level above the DVI injection point for Test Sbl4.
440.721(g)-18 TN
'4 NRC REQUEST FOR ADDITIONAL INFORMATION
-p ;;-
/\\ 6 ' t. i > < -
i
. 4.,'
~
t 4
Figure 440.721(g) 13 Companson of test effective level with NOTRUMP level increased by 3 feet for test Sb09.
T We Wighouse MO.721(g)-19
- r M
e~
NRC REQUEST FOR ADDmONAL INFORMATION l
i..
J (L,0 5
i f
4 e
Figure 440.721(g)-14 Companson of test effective level with NOTRUMP levelincreased by 3 feet for test Sbl0.
440.721(g) 20 IN
4
- o[ -
l:
'*o-NC', REQUEST POR ADDITIONALINFORMATION mp =
s:
nii...
l 4
0 4
1 s
Figure 440.721(g)-15 Companson of test effective level with NOTRUMP level increased by 3 feet for test Sbl2.
T Westinghouse M0.721(g)-21
_.. ~. _ _ _ _. _. -. _
. o A.
f'e' L NRC REQUEST FOR AD0mONAL INFORMATION oo
,r
/I '
A 4.0 4
I Figure 440.721(g} 16 Comparison of test effective level with NO11tUMP level increased by 3 feet for test Sbl4.
M.721(g) 22 T Westinikuss e
i I.
. ~.
--.