ML20081D548

RCS Draindown Evaluation Summary Rept

ML20081D548
Person / Time
Site:	Wolf Creek
Issue date:	02/28/1995
From:	WOLF CREEK NUCLEAR OPERATING CORP.
To:
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ML20081D511	List: ML20081D508 ML20081D548
References
NUDOCS 9503200289
Download: ML20081D548 (58)

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i WOLF CREEK RCS DRAINDOWN EVALUATION -  !

SUMMARY

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. I Introduction On September 17. 1994 the Wolf Creek Nuclear Power Plant experienced an inadvenent draindown of the RCS through the RER system to the RWST. De RCS was cooling down in Mode 4 at the time of the event. The RCS temperature was about 300 F and the pressure was about 350 psig. De operator was able to quickly terminate the draindown event by closing valve 8716A. Although the RWST overflowed to the waste holdup tank, there were no releases )'

to the environment.

Some concerns were raised as to the operability of the RHR pump and safety injection system )

assuming the operator hadn't acted swiftly to terminate the event. During this event, a mixture  ;

of steam and water was being pumped into the RWST. If the draindown event had not been terminated, the RCS would have began voiding and could have caused the RHR pump to fail.  !

Funher, if the RWST header, which is a common suction for the SI, CC and RHR pumps in i the ECCS injection mode, were substantially voided during the event, the safety injection pumps j would have failed if they had been started. ]

Dis letter report documents the analysis effort made to detennine the conditions in the RHR  !

system piping during the actual draindown event, in the worst case scenario postulated at the i beginning of Mode 4 shutdown, and several sensitivity cases. .

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Analysis Code Description De analyses were pe formed using the WGOTHIC code. De WGOMC code is an enhanced f version of the GOTHIC code purchased from Numerical Applications, Inc. in late 1990 (reference 1). De modifications made by Westinghouse to the GOMC code are related to  ;

providing additional heat and mass transfer packages suitable for modeling natural convection ,

within large volumes and annuti. De modifications include models for mixed convection heat transfer, evaporative heat and mass transfer, wall-to-wall radiation, condensate layer liquid film i tracking and application of subcooled liquid films. These modifications were made to facilitate  !

the analysis of advanced plant designs, but can be applied to other suitable modelling situations. '

The WGOTHIC code is a state-of-the an program for modelling multiphase flow. WGOTHIC actually consists of three separate programs. De preprocessor allows the user to rapidly create  ;

and modify an input model. De solver performs the numerical solution for the problem. The l postprocessor, in conjunction with the preprocessor, allows the user to rapidly create graphical and tabular cusputs for virtually any parameter in the model.  :

3 WGOTHIC solves the integral fonn of the conservation equations for mass, momentum, and i energy for multicomponent, two-phase flow. De conservation equations are solved for three fields; continuous liquid, liquid drops, and the steam / gas phase. De three fields may be in l thermal nonequilibrium within the same computational cell. His would allow the modelling of subcooled drops (e.g., containment spray) falling through an atmosphere of saturated steam.

The gas component of the steam / gas field can be comprised of up to eight different non-condensable gases with mass balances performed for each component. Relative velocities are calculated for each field as well as the effects of two-phase slip on pressure drop. Heat transfer between the phases, surfaces, and the fluid are also allowed.

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De WGOTHIC code is capable of performing calculations in three modes. The code can be  !

used in the lumped parameter nodal network mode, the tw o-dimensional finite difference mode. <

and the three dimensional finite difference mode. Each of these modes may be used within the  ;

same model. De capability of multi-dimensional analyses greatly enhances the ability to study l noncondensables and stratification as well as allowing the calculation of flow field details within  ;

any given volume.  :

i The WGOTHIC code also contains the options to model a large number of structures and '

components. These include, but are not limited to, heated and unheated conductors, pumps, i fans, a variety of heat exchangers, and ice condensers. These components can be coupled to i represent the various systems found in any typical containment.

WGOTHIC has been used to study hydrogen distributions, containment pressure and temperature  !

transients, perform flow field calculations for particle transport purposes, and surge-line flooding _

studies for loss of RHR cooling events during shutdown operations. De flexible noding and conservation equation solutions in the code allow its application to a wide variety of problems, not necessarily just containment pressure and temperature calculations.

The WGOTHIC code has undergone extensive review and validation against an impressive anay .

of tests. In addition to the AP600 small and large scale passive containment cooling tests, used  ;

to validate the improvements to the heat and mass transfer models, the code has been validated '

against a number of Battelle Frankfurt tests performed to study steam blowdowns and hydrogen releases. A selection of Hanford Engineering Development I.aboratory (NEDL) tests were  !

modelled to simulate steam hydrogen jets. De LACE tests were modelled to validate rapid  ;

depressurization events with aerosols. A variety of the Heissdampfreaktor (HDR) full scale containment tests were modelled to study steam and water blowdowns and hydrogen releases in ,

a full scale multi-compartment containment geometry. '

i Model Description r

The RCS model which was used for these analyses was based on the generic 4-loop plant model j which was developed to perform the surge line flooding analyses (reference 2). An RHR system i model was developed using data supplied by WCNOC (reference 3) and was merged with the l

RCS model. A noding diagram of the complete RCS+RHR system model follows. De RCS section of the model will be described first.

De core / upper pleous volume (2) was subdivided into 7 elevation planes and 3 channels to provide a reasonable pressure gradient and allow for a natural convection flow pattern through the vessel. The outer 2 core channels represent the banel-baffle and outer fuel assemblies and the center core channel represents the majority of the fuel assemblies. Decay heat was added to the center core channel only. Decay heat at the time of the event was estimawl by WCNOC to be about 19028 BTU /s (reference 3). De outer channel core cell flow areas were ma smaller than the center channel using variation tables. De upper plenum flow area was evenly divided among the 3 channels. The horizontal loss coefficient between channel cells above the top of the core was set to a very small value to promote mixing amccig channels in the upper plenum.

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The downcomer (1) was subdivided into 7 elevation planes to match the core clevation planes. i Dis is required to prevent artificial now between the volumes due to small differences in the  ;

pressure gradient due to an elevation head.

The lower plenum (4) was subdivided into 2 elevation planes and 4 channels. One channel was connected to the downcomer while each of the other 3 were connected to the corresponding core  ;

channel above it.

The RCS model contains 2 flow loops (hot legs, SG tubes and cold legs). The plant loop. from l which the RHR pump takes suction, was modeled as a one flow loop while the other 3 plant I I

loops were lumped together into the second flow loop. The hot leg volumes (6 and 14).were subdivided into 3 elevation planes with 3 channels to allow for possible counter current flow during the tunsient. A GOTHIC pump model was placed in the flowpath between the pump J suction volumes (12, 20) and the cold leg volumes (13, 21) to simulate the reactor coolant )

pumps.

The RHR system model simulates both the normal flowpath through the RHR-A pump back to I the RCS and the draindown flowpath to the RWST. De volumes, elevations, areas, diameters and loss coefficients for the RHR system model were supplied by WCNOC (reference 3). The noding structure was based upon the data supplied by WCNOC and by review of the piping 1 isometrics.

The RHR system model was modified over the course of this study to correct problems which were discovered while performing the analyses and to improve the transient modeling. In an earlier model, the header was split into 2 volumes; one supplied suction to the "A" train ECCS pumps and the other supplied suction to the "B" train ECCS pumps and was connected to the RWST. De flowpath connection to the RWST was placed at the top of thr "B" train header volume and had a height of 0.1 ft (standard for a vertical connection). With this model, the fluid level was predicted to be near the top of the "B" train header volume throughout the transient. His resulted in an artificially low header volume void fraction which didn't compart with the incoming fluid void fraction (approximately 90%). The header void fraction problem was corrected by creating a separate vertical header volume to connect to the RWST and using a larger vertical flowpath connection height at the top of this volume. The "A" and "B" train header volumes were combined into a single horizontal header volume to elim'mate level differences which were observed during the transient simulation. Also in an earlier model, a constant heat removal rate equal to the core decay heat + pump heat loads was used to simulate heat removal by the RHR heat exchanger. The constant beat removal was turned on while the RHR pump was running, but was turned off after the RHR pump failed. A GOTHIC heat exchanger component was used in the final model to better simulate the heat removal by the RHR heat exchangers throughout the transient.

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A brief description of each volume in the final RHR system model is given in the table below:

Neds Desenption 22 From hot leg 1 to Tee F010 23 From Tee F010 to RHR-A pump 24 From RHR A pump discharge to Tee F025 25 From Tee F025 to Tee F017 26 From Tee F025 to Tee F017 (including the RHR heat exchanger) 27 From Tee F017 to HV-8716A 28 From HV-8716A to BN8717 29 From BN8717 to Tee F034 30 From Tee F034 to Tee F007 + From Tee F034 to Tee F045 31 RWST 4 32 From Tee F045 to SI-A pump suction -l 33 From Tee F045 to CCP A pump suction 34 From Tee F024 to SI-B pump suction 35 From Tee FW309 to CCP B pump suction 36 From Header to RHR-B pump suction 37 From RHR-B discharge to RCS 38 From Tee F007 to RWST The location of the GO1 HIC heat exchanger component significantly affects the transient results after the RHR-A pump is tripped or assumed to fail. If the heat exchanger is located in path 37, volume 26 will be subcooled and a large fraction of the flow will pass through flowpaths 37 and 39 resulting in higher energy removal. If the heat exchanger is located in path 39, volume 27 will be subcooled and flow will be split more evenly between paths 38 and 39 resulting in lower  :

energy removal. The RHR A heat exchanger was placed in flowpath 39 to be conservative. i The GOTHIC '!IME-OPEN valve component was used to simulate valves 8716A and FCV618 l in the RHR system model. These valves were modeled to open over a 15 second time frame j at the event initiation. A GOTHIC TIME-OPEN valve component (with a 15% void fraction i trip setpoint) was also used to simulate the failure of the RHR pump and subsequent increase in 1 loss coefficient when the suction void fraction exceeded 15%. The GOTHIC check valve i component was used in the lines connecting the ECCS pumps with the lumped loop cold leg and l in the RHR discharge line.

GOTHIC pump components were placed in pads 35 (RHR-A),54 (CCP-A),55 (SI-A),56 (SI- l B), 57 (CCP-B) and 58 (RHR-B). The homologous curve input data for these pumps was  !

derived from the head flow data curves supplied by WCNOC (reference 3). j Model Lindtations j There were some limitations in using this lumped loop model which may affect the transient  ;

results slightly. These are listed below-

1. Although the plant operates with 2 RCPs during cooldown, this model must have all 4 pumps running to get the proper loop pressure drop and flowrates.

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2. Piping and vessel metal was not modeled. Metal mass could act as a heat sink during  ;

the hearup following the RCS draindown through the RHR system. l

3. '!he SG secondaries were not modeled. This fluid could act as a heat sink during the  !

heatup following the RCS draindown through the RHR system.  !

4. The RCPs cannot be run longer than about I minute without the computer run abortinF-  !

Pump Operability l General Discussion

'Ihe issue of pump operation in the presence of gas mixtures or voids has been the subject of  ;

much industry discussion in recent years. Since the presence of gas has been postulated as a j contributing cause to many of the pump failures experienced in recent years. and is censin to i be a factor in the current evaluation, the following summary of concerns and impacts of gas effects on the Wolf Creek residual heat removal (RHR), centrifugal charging / safety injection (CH/SI) and safety injection (SI) pumps is provided. All of these pumps were designed and  :

manufactured by Ingersoll-Dresser (formerly Pacific) Pump Co ("IDP"). The RHR pumps are i model SPF, vertical, single stage,1800 rpm pumps. 'Ihe CH/SI pumps are model 2-1/2" RL-U, horizontal,11 stage,4850 rpm pumps. The SI pumps are model 3" JHF, horizontal,11 stage, 3600 rpm pumps.

The introduction of entrained gas into the suction of a centrifugal pump will have both hydraulic and mechanical effects on the pump. The gas will result in a reduction of the pump developed head and an increase in the net positive suction head (NPSH) required by the pump to maintain operation without excessive cavitation. These hydraulic effects are magnified as the gas void percentage increases. The gas will also result in increased vibration levels and bearing loads.

These mechanical effects are also magnified as the gas void percentage increases. As gas void percentage increases, the void will eventually reach a critical level at which the pump will lose prime. Loss of prime will result in severe reduction of the pump output and willlikely result in immediate, short term failure of the pump.

i Westinghouse has searched literature and held discussions with IDP to try to assess the hydraulic and mechanical effects of homogeneous mixtures of gas entering the suction of these pumps.

Several documents which were reviewed provide information regarding the hydraulic effects of increasing levels of entrained gas. One of the more relevant documents for the nuclear industry is NUREG CR/2792, entitled "An Assessment of RHR and CS Pump Performance Under Air and Debris Ingesting Conditions." This report concludes that gas levels of 25 by volume will generally resuk in negligible hydraulic degradation and that levels up to 55 may be acceptable based on a specific pump design. Work performed by a consultant to the NRC within the past few years has indicated that gas levels of greater than 205 will guarantee loss of prime.

Unfortunately, NUREG CR/2792 and the other reports that were reviewed did not provide the means to quantify and predict the specific mechanical effects of entrained gas on centrifugal pumps. It is known that gas entering the pump can result in a radial and axial imbalance of the ,

hydraulic loads on the pump impellers. The imbalanced hydraulic loads result in increased pump l rotor vibration, increased shaft deflections and increased bearing loads. These effects can lead .

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to mechanical pump problems including abnormal mechanical seal wear, abnormal bearing wear and an abnormal fatigue stress process in the pump shaft. De impact of these effects on an individual pump is dependent on the specific pump design and on the level of entrained gas.

Unfonunately, the literature does not provide specific information necessary to quantify these effects.

Continuous Oneration j Over the pan few years, Westinghouse and IDP have reviewed the design and application of the l CCP, SI, and RHR pumps for operation with entrained gas. Based on the available literature  :

and knowledge of the pump designs, our best engineering judgement is that the pump hydraulic perfonnance would not be significantly reduced with entrained gas levels of up to 5% by  ;

volume. It was also our best judgement that, based on no expected adverse hydraulic effects. l the mechanical effects on the pump would also be minimal. Rus, it was concluded that l operation with up to 5% entrained gas should be acceptable. Since the 5% limit is not yet l supponed by rigorous test or analytical results, it should be considered a guideline and not an I absolute limit. In general, the level of entrained gas that enters these pumps should be l minimized whenever possible. l I

Westinghouse and IDP have also attempted to evaluate the effect of gas slugs greater than 5 %  !

i entering the RHR pump suction. No literature or model-specific testing was found that would allow justification of an assumption of continuous safe operation with gas slugs greater than 5 % i by volume. However, this does not mean that a pump would immediately fail if the gas void

• reached greater than 5 % by volume. He available literature indicates that some pumps may be capable of operation with up to 20% gas void. Westinghouse and IDP have concluded that the  !

design of the Wolf Creek RHR pumps is not likely to tolerate continuous operation with much  !

more than 15% gas void, and possibly not that high. Stated differently, in the presence of a continuously rising gas void ratio, the RHR pump would probably fail by the time the void ratio ,

i reached 15 %, with almost certain failure by the time the void ratio reached 20% by volume.  :

Shon Term Oneration

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Sudden exposure of the RHR pump to large gas voids is generally considered to result in short j l term failure of the pump. A large gas void is probably any size greater than 15% to 20% by

volume, although there is no specific established threshold size. In the Wolf Creek RHR pumps, j introduction of a large pocket of gas will result in damage to the water lubricated shaft sleeve, i i or journal, bearing, which is in the upper region of the pump body cavity. De gas will also i migrate into abs shaft seal area, resulting in short term seal failure. At the same time the i damage is occurring to the bearing and seal due to loss of lubrication and cooling, radial and i i axial imbalance of the hydraulic loads on the pump impeller will also occur. De imbalanced i

hydraulic loads will result in increased pump rotor vibration, increased shaft deflection and j increased bearing loads. De increased shaft deflection will lead to evenmal wear ring seizure,

concunent with the bearing and seal failures. Field experiences have verified that such failures

, can be expected, although the exact sequence of the failure progression can not be predicted.

j Westinghouse is unaware of any test data which would enhance our understanding of this issue.

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h Summary of Analysis Results  !

For all of the cases. a steady state period of 300 seconds was run prior to opening valve 8716A.  !

The event times discussed in this section are the times after the 300 second steady state period.  ;

The actual RCS draindown event was modeled as a benchmark test case (Case IA) with the  !

combined RCS+RHR system model described above. Table 1 compares the model with the  !

plant data. j TABLE 1 Comparison of Initial Conditions (@ 300 seconds in the WGOTHIC model):

WGOTHIC Model Best Estimate Value (Plant Data)  :

RCS Temperature 297 F 300 F  !

RCS Pressure 345 psig .

340 psig (hot leg)  ;

Pressurizer level 720 inches (hot leg bottom) 743 inches (hot leg bottom)  !

Pressurizer Temperature 354 F (avg) NA i RHR Suction Flowrate 2898 gpm (370 lbm/s) 2800 gym RHR Bypass Flowrate 392 gpm (50 lbm/s) 400 gym  ;

RWST Level 995 (41.45 ft) 99 5

-l Comparison of Final Conditions (@ 370 seconds in the WGOTHIC model) l RCS Temperature 308 F 307 F RCS Pressure 204 psig 225 psig (hot leg)

Pressurizer level 288 inches (hot leg bottom) 361 inches (hot leg bottom)

Pressurizer Temperature 385 F NA RHR Suction Flowrate 3838 gpm (490 lbm/s) NA RHR Bypass Flowrate 1919 gpm (245 lbm/s) NA RWST Level Full Full (overflowed)

Integrated Flow to RWST 9625 gal 9200 gal Note: The information in this table is from Reference 5.

The combined RCS+RHR system model calculated a slightly higher RHR flowrate during the event, and e n:7 y a1 higher integrated flow to the RWST. This may be due to the' modeling assumption which caused the bypass valve to open at the same time and rate as valve 8716A. The results are shown graphically in Figures I through 4. The calculated flowrates through the RHR heat exchanger and bypass line were nearly equal after the event was initiated (Figure 3). Heat removal by the RHR A heat exchanger prevented any signifmant voiding in the RHR piping downstream of the RHR pump (Figure 4). The results from this case and the other cases described below are summarized in Table 2. 4 Case IB was run to provide a sensitivity to the ratio of the flows through the heat exchanger and j the bypass line. The results are shown in Figures 5 through 8. For this case, the flow through l i

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the heat exchanger was reduced to approximately 30% of the total RHR discharge flow after l 8716A was opened (Figure 7). Although there was significant voiding in the RHR piping downstream of the RHR pump, the RHR discharge header had sufficient volume and was at a low enough temperature to condense the steam and remain at an insignificant void fraction during the event (Figure 8).

Two cases were run to determine the system thermal hydraulic response without operator recovery actions (except to trip the RCPs at 15 seconds after event initiation). Case 2A. started from the actual event initial conditions and Case 3A started from Mode 4 initial conditions, i.e.  ;

350 F 400 psi,25% level. The Case 2A results are shown in Figures 9 through 13, and the ,

Case 3A results are in Figures 14 through 18. For both cases, the vessel began to void within 2 to 3 minutes after event initiation and the RHR pump was predicted to fail (15 % void fraction at the pump suction) about 30 seconds after the vessel began to void.

For Case 2A. the vessel collapsed fluid level remained above the top of the core while steam and water were being discharged to the RWST (Figure 11). For Case 3A, the vessel collapsed  !

fluid level oscillated around I foot below the top of the core, however, the mixture level would be expected to be above the top of the core (Figure 16). For both cases, the time to core uncovery was estimated. For Case 2A, it was estimated that the core would be uncovered j around 30 minutes after the event initiation. For Case 3A, the estimate was about 20 minutes.

In Case 2A, the header void fracticu reached 90% around 6 minutes aAer event initiation.

(Figures 12,13). In Case 3A, with a higher initial temperature and pressure, the header void  !

fraction reached 90% around 4 minutes after event initiation (Figures 17,18). After this, a i condition known as flooding exists in which the steam flow through the vertical section of the l header is high enough to hold up the liquid in the RWST and prevent the header from refilling. l A third case, Case 3B, was run to examine the effects of tripping the RCPs at 1 minute after i event initiation instead of 15 seconds. The results are shown in Figures 19 through 23. For this [

case, the vessel began to void around 3 minutes after event initiation and the RHR pump was i predicted to fail about 20 seconds later (Figure 21). The vessel collapsed fluid level oscillated ,

around I foot below the top of the core, however, the mixture level would be expected to be  !

above the top of the core. The results of this case are very similar to those of Case 3A. It was [

estimated that the core would be uncovered about 20 minutes aAer the event initiation.  !

Case 4A was run to determine the effect of starting an ECCS pump while the header was  !

voided. CCP-A was staned 5 minutes after event initiation and ran for less than 1 minute before the pump suction void fraction would have reached the assumed failure limit of 5 %. During this l time the pump.was taking suction from the header only, since there was no flow from the RWST due to flooding in the vertical section of the header. Note that in the model the pump was  !

tripped at a void fraction of 15 as shown in Figure 29. This case was not rerun because the  !

CCP-A suction void fraction would be expected to increase rapidly as the pump continued to j run. The results are shown in Figures 24 through 29. l i

Two recovery scenario cases (based on simulated operator recovery sequences which were run i on the simulator) were analyzed next. 'Ihe purpose of these cases was to try to determine conditions at the ECCS pump suction during the simulated operator recovery sequence.  !

Following the event initiation, the operator shut off RHR-A pump at approximately 100 seconds, ,

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valve 8716A was closed at 840 seconds, and pumps CCP-A SI-A. and and RHR B were staned at 300 seconds. 815 seconds, and 900 seconds, respectively. Case 12B staned from the actual event conditions and Case 12A staned from worse case (Mode 4) initial conditions.

Case 12B did not run long enough to give useful results. For Case 12A, the pump suction void fraction exceeded the assumed failure limit for both the SI-A and CCP-A pumps immediately after the pumps were staned. The RHR-B pump staned at 900 seconds after event initiation.

however because the RCS pressure was above the shutoff head of the RHR pump there was no injection now from the pump and the pump suction void fraction remained well below 5 %. The header void fraction dropped from about 95 % to below 40% after the RHR draindown path was isolated. Case 12A results are shown in Figures 30 through 36.

Another case, based on Case 12A, added a boundary condition for the RHR pump B discharge to examine the effects of running the B pump on the pump suction void fraction. This case.

Case 12C, staned from the same conditions as Case 12A. The results from this case are shown in Figures 37 through 42. The code predicts that the void fraction remains low once the pump is staned (Figure 42). Although the void fraction in the RHR pump A discharge header is high at the time RHR pump B is staned, the flow pulled into the pump B suction volume condenses the steam and the pump does not trip on void fraction. ,

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TABLE 2 i

initial Conditions Results Case Descripeian RCS Init RCS lait Pra lait RCP Valve RCS level RCS RCS LCCS PW Comneents

1. Temp Press (hot level Trip 8716A Temp Press Seese (hos leg) leg) (hot leg Time Close (hot (hot leg) bonom) Tinie leg) 1A Benchmark to plant 2FF F 345 peig 720 in 15 sec 66 see level in 308 F 204 peig Au , "i.

conditione. 8716A par < l % vanimag in  ;

classe en demand. ECCS comamm header IB Case l A wish 705 297 P 345 peig 720 in 15 sec 66see level in 306 F 205 psig As _ , ' _" .

.bw to RHR Ha par < I 5 vanhng in bypese,30% to Ha ECCS common header 2A Case I A wish 297 F 345 peig 720in 15 see Does imid-loop 350 F 115 peig ECCS common Rusi shorts -738 sec 8716A open not S 310 see header high void close fract 9 340 see 3A Case 2A wish Mode 340 F 39n peig 342 in 15 see Does neid-loop 398 F 230 peig ECCS common Run shorts -798 sec 4 initial condicione not e 220 see header high void close fract 9120 see 38 Case 3A wish RCPn 340 F 390 peig 342 in 60 see Does mid-loop 385 F 200 peig ECCS comunen Run shorts -606 see tripped at I h not G 220 see header high void l close fract e 120 sec

! 4A 297 F 345 peig 720 in 15 see Does smid-loop 364 F 145 peig ECCS comnion Run shorts -9e0 see Case 2A wish CCP.

i a seest et 300 see, not 3 300 see header high void I close fract e 340 see II

loisial Conditions Resehs 12A Based on senaulator 340 F .190 peig 342 in 60 sec 855 niid-loop 450 F 415 psig ECCS comunun I

run. RHRpuenyA see e 290 see header high void off st 102 sec, fract O 120 sec.

8716A closed at 855 k H R B void sec, steesnyt to seert fract < 5 %

l CCP A. RHR B.

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12C Case 12A with How 348 F 390 pois 342 in 60 sec 855 said-loop 450 F 410 peig ECCS comunan l

froen RHR B to new see e 285 see header high vid i " _ _ ' _, condition fract O 120 sec. ,

TABLE 2 NOTES Notes: All tW tienes are the sieme aner the 300 second siendy sense period.

Initial conditions are at 300 seconds.

Case I A resuhs asken at le seconds aAer the secedy sense period i

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Conclusions -  ;

-i The Wolf Creek RCS draindown event was analyzed from both the actual event initial conditions i and at the conditions upon entry to Mode 4 operation. The following conclusions are based on i the analysis results presented in reference 5:  !

1. Assuming the operator trips the RCPs at the beginning of the event, the operator would  !

have only about 3 minutes after event initiation to terminate the RHR flow before voiding l begins in the upper plenum and hot legs. De running RHR pump would have to be -!

tripped or would fail soon after voiding begins. l

2. While the RHR flowpath from the RCS to the RWST exists, the header void fraction will

• be about 90% and the vertical section of the header pipe leading to the RWST will be l flooded preventing liquid flow from coming back from the RWST to refill the header. l l

3. Starting any ECCS pump prior to isolating the dmindown path will result in a high void  !

fraction at the pump suction and subsequent pump failure.  !

4. Because the model does not include either steam generator secondary or RCS piping heat  !

sinks, the RCS pressure and temperature are predicted to continuously increase after  :

RHR cooling is lost. The RCS pressure is predicted to be greater than the shutoff head j of the RHR B pump at the time it would be started based on the simulated operator  ;

action times. The RHR B pump suction void fractiou remains below the assumed pump l failure value of 5 % for the cases examined. This pump could be used to provide cooling ,

flow to the RCS if the RCS pressure was reduced.  ;

5. For the cases in which the pressurizer empties, once the draindown path is isolated, the discharge header mun be refilled to the point where an ECCS pump can be started. The l model estimates that it will take at least one minute for the header to refill sufficiently i to allow the RHR B pump to be started without causing its suction void fraction to j exceed 5 % (the assumed failure limit for continuous operation). This time frame would l also apply to a CCP or SI pump since the flowrate from either of these pumps is i expected to be less than the flowrate from a RHR pump. Note, the model predicts that  !

the RHR discharge header will refill to a level of approximately 60% in about 5 minutes.

6. The collapsed liquid level remained above the top of the core, or was close enough to f assume that the mixture level would remain above the top of the core, assuring adequate core cooling over the time period analyzed in these cases (< 1500 seconds). If valve 8716A was not closed, k was estimated for the worst case that there would be  ;

approximately 20 minutes from the time the valve opened until the core would begin to .

uncover, i i

i 13

.,. - . - . , . . . _ ,.,a -. - - a

y V. , ~

References

1. " GOTHIC Containment Analysis Package User's Manual", Version 3.4. April 1991

[ 2. WCAP-14089, rev.1. " Analyses to Develop a Basis for Surge Line Flooding Response

' }' to support Shutdown Operations"

3. Calc note CN-CRA-94-208 R0 "Modeling the Wolf Creek Mode 41.oss of RHR Esent with WGOTHIC", Appendix A

4. NUREG CR/2792, "An Assessment of RHR and CS Pump Performance Under Air and Debris Ingesting Conditions"

5. Cale note CN-CRA 94 208-RI, "Modeling the Wolf Creek Mode 4 Loss of RHR Event with WGOTHIC" 14 a

s

• • s Wse a ece s a**o

• 8*8 a's -X lase

• A

".e .a* 2' " 2? 2: M5

. s: -: v.w 4,7 c :. a :c a 123 :' c

• r i

RCS Pressures (psta)

{

PR3 PR2s2 PR5s1. Pads 3 PP6s9 i g . _ _ _ . . . . _ . . . .

e p_ . . . _ _ . .

gi----4  :

lI A

> =P.* M ; . pp.

\

I .

\

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1 8

r e

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w QCThC 10

_ StP96 00 0C N i

L Y

h i

i MGURE 1 s

t i

n 4

a ,

1w:e a sc 34 e-:-:r:-r: .t

• e.r 3272' M5 2: -:vew es;r:2: .4 Oc as s 22: c? w  !'

RCS Lewd Temperatures iR ,

g TL2s8 TList TL5s1_ . . . . - .

.TL3 -

t g '.. . - .

c

.r _

N --.- - ... u q-- - - . . . . . . . . . . . . . . . . . . . . . .

. N

\ .

ss ~ ~

1 i

,,~~~ ,

t e a I 1 e t i I Q 0.3 0.6 0.9 1.2 1.5  :

X1E 1 Time (soc)  ;

9 w oewc s e eigew w a s i

r i

l I

l I

d i

1 i

RGWR 2 .

i 1

3 *1 Ww a res s a e- -: a*:-r ase ' A f

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. ,: -:,e ie n.;:r::: ,e:::: s as: c? w l

RHR Hx anc Bypast flewrates iltms) f

-l g. FL36 FL37 .- -  !

x -

t g~ n o

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. e

. i  !

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a

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i i

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o . ,

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9 . . . .... i... i....... . '

0 0.3 0.6 0.9 1.2 1.5 ,

X1E  !

Time (sec) i w 3C*wc 1 e 01796 09 OC N 9

i 3

l 1

1 i

l i

1 t

MGURE 3 i I

5:3 w:e a acc re- e-8 8 c:-r :me a

• . e.s 2< *21g* m 3; -: <e sce n-;;r:2 : *.e Oc'21 t 22 : E:* %

~

p RHR System Vapor V:lurre 'a:t.ons i AV28 -AV29 AV30..AV38 3

mo o  :

_T . .

a -

x . .

w -

6 -

ev d -

p e ". . I L-- L----1 - >1- --

0 0.3 0.6 0.9 1.2 1.5 X18 Time (sec) w act c e we a z e.

MGURE 4 t

4 i

I

8:1 w> a cer ra e - -* e- -r :ase 3 ,

3* tot 2*t*A at'wi

- 3: - : wew *.,:r c 2 : .*.e Oc: af t 23 :' E:* **

' I RCS Pressuesipse)

PR3 P82s2 PR$si Pres 3 Pm6s9 g _ _ _ . . .._ . ....._ _. .

~...... g i

g L-----e .

a . '

_.._. _ _ . D L 1

.i i I E .

}4 l .

t

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_ , J R .

i E _

i f

. r t ,. . ! , . . i , , , t . ,

1) 03 06 0.9 1.2 1.5 X18 r < c) .

w 20 test

• 9 t 'Wgi 'O M 'l  !

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1 i

I i

I I

i I

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. MGURE 5

I t

8:5 ve:e 4 :::: a. -

• 8 s-2 s "ase g -

• • 8e: ) 13 4e w5 l 3: -: .ew W.;:t:2: ~.e *::25 123 E:7w  ;

I RCS Leue Tempereues Ji  !

5 g TL2s0 -TList

- - . .TL$si Tu.3 r

c )

. t

.- g _-  :

t

- i A

g _ - - ... f _ . ~ h -s _.... ... . .._ .... ......... .

~~~~-----_--____. p h

4 i

p I f f I t f 1 I t i i t t 3

l} 03 06 09 1.2 1.5  :

X18 Time (sec) i

. rue . e e se .e n .s

,t r

,r 1

P f

t h

1 r

9 i

MGURE 6 -

l 1

l f

4 i

i

)

. 8:l W:e a ::2:a '*

• 8 s*:-s :sse 5 Aees e: i ni set

~~;.e:: A.:: 2 : *.e :: 25 122 :' E: w j l

l RHR Hx anc Bypass Fiewra:es ' ems) .

1  !

g ,FL36 FL37 Xs , 1  :

I F i i .

r .

l NI .

- m - l i o -

si 1 -

li e

is e

o - i, 6 .

n

,____(,;V _

L i t t__________________

. . , i. i. .I . ,

i) 0.3 0.6 0.9 1.2 1.5 X1E rm a.c) re-c o twen s i

l l

i i

1 I

4 i

MGURE 7 l

1 I

l l

i

.. l 3:1 *e:e 4 ::: g *** *

• 8 8 s*8 "I M 'I l

• . 8e J:s:er ut  !

3: -; .e :: .,.;: :2 : *.e ::'If 'l 23 : !: na ,

. RHR System Vapor VoLrre %:ters AV28 AV29

___. AV30 . .AV38. .. i b i L i

. r r

s_____________________

e L-8 i i

e t -

I T.

- . p' o -

w w

o -

~

1 I I n - l o -

i l i

6 i 1 I i  ! ,

f 'l

• _i _ _ '

, , m i _.___.__m __ _1 ---

0 0.3 06 09 12 1.5 i X18 Trne (sec)

_ gS f

i

[

a

[

t I

FIGURE 8  :

t 5

i

?

1ww 4 :::r e-:-* a s-s :4 ga

- ".e .c 2 ** 3 x Mi

. 2: -:,e s e.cs:r : 2 : .d :c 21 t a : n na  ;

RCS Pressuresipse)

PR3 PA2s2 PR$st Pads 3 Pn6s9 .

g _ - . . . _ _ - . . _ _ . .

<s ----.

rs - - - -

g g.

r s . , -.. 3

/  !

's n

ti ,

E_. .

{i l 3-

- r.

4-=~

o' 0 0.3 I

06

. , t 0.9

. . . i, 1.2 1.5 X18 r= m ,

w sex 4 o true o e

6 l

I I

1 MGURE 9 i

k y

l

w:e 4 ::::..... - c:-a 1:n ta e .e 2 :t 2 ut

. s: -: ,ew w.;: c 2 : .e ::'It 'I 23 :' E:* w RCS L:cwe Temperstares Is TL2s8 _TList TL5s1.--.

TL3 g _ - . .

R-n-

E o-

19. . ,

f': l 4

~ N?- ,'

r -- ..,;--s~~~.

7 ,

? e g -

P E

R-

"' ' ' . i , , , t , , , , s ,

O 03 06 09 1.2 1.5 X18 tim.<.w

. ce~c , , 3,y u . o MGURE 10 i

. - . . . ~ . . . -

. *-.. t 3:1 */::e 4 :::: i>* .

• 3-3 *t * .,se ja ,

.e .e* ; * :t s* ut l 3:*-: w s:*t..:: :;; *.e*: J!'l2;; n 144  ;

a- .; .

t Vessei Levets .iti LL252 .. s1 ..

• g .'. _ . . ' 3.-

6

. l ,

i e.s - --

~___________________

8  !

- i S .

R _. .

. i E . ,

e ._ l g- -

t e ,

e, - , , i i ,, i , , , i ,

0 03 06 09 12 1.5 , ,

X10' Time (sec)

I

. ::w . 3 v ni s e i, MGURE 11 J

i '

- *:1 *.t:e 4 ::r: a... .: ..: .s :. . ga l

• a.e-: :ta ast

, :: -: .n: i..::-:;: .e :: 25 t n: f: w-

! RHR System Vapor Volume 'acces j AV22 .AV23 _

AV24 AV25 AV27 .

, s.a .

o-. . ,,.. .

t 4, ' l

- . f -a ,

T

. ,e. .

- e s i o- ,. 'l s, i a

8-  !

c .

I 8

,- , si ,

O $l

', l

l. 1 u- l e o- d a 4 .

F L _I '.

f . . - - - .

o . .

0 03 06 09 12 1.5 X18 Trne (sec)

. :e -c 3 mn3 w i i

6 FIGURE 12 .

r i

3;1 *r:e 4 :::a r e

• 8-3 s* : - 8

• 4se 2A

".e,e*2 ** t42 4f

,: -: .cs:-i..;: ::: .*. e :: 25 !n : f: ne

?

AHR System Vaper Vocee F a: tors l

'AV28 AV29 AV30 AV38 i *

, g ,

= r a- a .', i . .

. l . .- t

. I; .

. I. . <

T

- e. 1- i, ,'

a-

. I ,, i'

- , t

,- 4 o- , 7 i '

i i i .

n, - ,

,  ; i o- i  ;

1

-  ! l

. p

. i .

, , , _ 1 ., , , , . ,

0 0.3 0 di 0.9 1.2 1.5 ,

X10' i Time (sec)

• ,-' < e ytes a sit i l

I t

i fl l

6 h

h MGURE 13 e

8*1W:e 4 ::::r e- 8-8 es-r :as,sa

. r e: 5 * * ;4 f f sti

-+ 2: -: <e s e u ;:r s 2 : . :c ts t 22 : t: ,w RCS Pressures (psian PR3 PP252 PR5s1. Pads 3 PR6s9 g - - - - . . . . . ..

o . >

S ~.

i

-__i

__ g

{ $ .;- z- t : .]i

~

E .

- s .--m Y.

8

,,,,t ,, t , ,,t ., ,i, ,

0 0.3 0.6 0.9 1.2 1.5 X1E Time (sec)

.xsc ,o um .. ., s.

l i

e MGURE 14 1

l

• *I %ee' e tec te* e5 3-3 es =E'*,me n s

"* 8ee 9 ** 3t x c*!

, s: - c ve sea ws:n n. :ca s n : c su RCS Lique Temperatures (F) l g TL258 -TL1s1_.

TL5s1. TL3 ST5s1 .

.a

.m c g

• =-..,__.._..

g .

g . 3 1

g i e- $ -

i

} M  ?

.c

, .s..,y=====~~~~,,_ ~' :"

R - - - -- ......i .

'Y '

~d

\1 e i l t i i  ! t i i i l i i i i l e e a 0 0.2 0.4 0.6 0.8 1 X18 Time (sec) 1

. acwe , e m ..ei n i

I i

6 MGURE 15 t

ve:. ne:: ..- -s es-r : a -

• - see s -

2: -:v.. ,n x mas: :::. .e se n s n:,sr m - ,

. ... - i 4 .

Vessel Levels (ft) l L12s2 _LL1:1. LL3 i g _ _.  ;

L I  !

tr_ .

. I

---

w ___________ ,

I R _

E -

i m -

- -l; o

.- i m - ,

. i g i g g i t l l f T'* 1 I f f 1 0 0.3 0.6 - 0.9 1.2 1.5 >

X1h 1 Time (sec) t wENC i e t19498 $4 di e i i

e t

i 4

i i

i I

t l

I i

FIGURE 16  !

1 i

i

8:3 m a nes co-: : r:-x :ase 3A

• • . *n p " 3s *4 'C E 37-ic vown w$ctc 2 : 4 *.4:25 123:1 CT toes -

i

+

RHR System Vapor Votume Pa:tions j AV22 AV23 AV24 AV25 AV27

.' .'/ " M/ A\

,fi/\*lhg f ;'hf ^ ..  ;

a -

.. i -/,/#  !

i

= i ." l \

i" ; gg

{

--- w ei ,

d ~

klj ,

- I

I  !

i,b, e .

.g -

la f 6 -

is t

. I'l

- 18j

. . p.;

i d ts j

~

~

l gi.)

p

. fi ii,,f l . , :r , I .,,e l . , , e n ,,,

0 0.3 0.6 0.9 1.2 1.5 X1E i 3

Time (sec) ,

W QCNC

• O C^^"' to 41 Op i

F A

I I

6 FIGURE 17 .

p-i

s ww 4 :e::a -: 8 c:-s *me sa  ;

r. - **,8eci"at:1 Mt d

- 2: -: ww cs:r ea : .e :c:2tsneim ow i 1

L  !

RHR System Vapor Volume era: tons l AV28 AV29 AV30. AV38, --  ;

. s. 7

.  : t I

. of 3 - .

= e -

. - e  :

8: ,

e.

5 -

g-

,l .

' )

i- .

1

.. g m -

l 1

o -

l

. I:

l

i. j o ", , I J: i,,,,t ,,,,i,,,. l 0 0.3 0.6 0.9 1.2 1.5 X1E i Time (sec) woewcse eso es ,e ei a j

a i

I 1

l l

l l

l l

l i

l i

MGURE 18 1

.. j 3:1w:e 4 at:4-:e-: : c -r Lse as

• • . re ; I " :I at-M i 3 -: vew c.;:: 4 2 :.*.e *cil 't 23 :t C* Des E

i RCS Pressures (psia)

PR3 PR252 PR5s1 PR4:3 PR6s9 6 i

e .

S m.

n

___i

\,

j:.". .., . . . .. . . . . 3l I .

j RF ,

k -- ~ g .

. t 8

~ , ,,, i, ,,i,,,,i, ,.

0 0.3 0.6 0.9 1.2 1.5 X18 i Time (sec) l woeme , == ,. . v I

i L

i FIGURE 19

i a:s ww. ece rre-: : c:-* 04= 0 e l

. s.:v e.w:s c,cs,

c. :r a : ...:c: rs s 22 : 1 c ow '

~

i r

r RCS Ligud Temperatures (F) i g TL2s8 ._TList _ TL5s1

. .TL3 ...ST5s1 . - . . - .

\ r

\ \

1  ;

li ,

h n -

l u o - -

$ s p

I e e9 i

{ %.. .,.

,e

. /p f" ,

.\

- '. '.s A

R ,_ _ _- - -.. ..,,. -

(i .i

. .;' . t

, g , , l , h t t t I I 1 f I a o.2 os u u fg t Time (sec) t

. xse ,, u m .. v t t

i.

i I

FIGURE 20

~ l 8:5

• w a crea* ee t 8 rs-X ".me23  :

• • 8ec ) ' :1d CE  !

.-  :,: -: se w *Su 2: e c:25 5 22: ci m i

i Vessel Levels lit) i LL2s2 _LLis1 LL3 i g _ _.

M ~.

. 1 g .

El -

I  !

y .

i.___~ - -

e - k

. i a .

e t

~

O ' ' I ! 'I 'I

' ' ' .5 0 0.3 0.6 0.9 1.2 1 i X1E  !

rime t c) i W E ?>C 10 24W9610 ed 31 t

e J

i

(

l l

i e

1 l

1 1

F FIGUILE 21 i

l i

i 1

e

_. -.__________-i

w , , x, g ..- :.: es .: ;4 g-) -

• • . 8m s s u ci

. - s: .c v."w wvres:. e:c is s22:i av m t

L RHR System Vapor Volume Fra: tens t AV22 ._AV23 _ .

AV24 AV25 .

AV27 1

e ,,.s.  !

- 1 t

. ,o .S 4- 3j\,~

't  %* I 'n , pa. .

so

- l I fil Qi

.,o o o - s yg

. .. a Y

- e t1 o -

I,i

. n<  !

i c -

r!

w -

11 8

7 l'

. II

- /*

ew / !

c5 - i f ,

. I 1 8

. /

~

1 .- iie ,f . i l o #

, . i , , .

0 0.3 0.6 0.9 1.2 1.5 i X18  :

Time (sec)  :

W30%Ci4 01(W9614 ed 31 L

r i

i I

r I

i i

i t

6 FIGURE 22 I

- - - . ~

s w, , ee,g am.. .: sc-r : 3g  ;

• • 8ee a ":s ls MI  !

1".*- C We's.ca W p? c 2 : *4 , "At 21 'l 22

• ET '994 i t

RHR System Vapor Volume Fractions i

AV28 AV29 ..AV30. .AV38 . . _ .

t  !

- i o - .J

?

m 4

! ,/

'm l

l

• e - t  ;

o - I; 4

- e.-

. t C -

, s .,

o - f t:

ew 1 o ~

i t

. .: I

l 1  !

o

~

,iS1 1 Il, ! ,,,,i,,,,,,,,, I 0 0.3 0.6 0.9 1.2 1.5 '

X18 Time (sec) l W GCNC 9 0 OMwel te m 31 t

I i

i h

b MGURE 23 1

8"l W:e a ::rt a- s* *=8 a*3-X lme sA

• • 8ec 6 M 21 *MI 1 s: -: v."w *Sr : 2 : .e :c 25 22 :* CT 'Ha I i

RCS Pressures (psta) ,

g PR3- PR2s2 -. . PR!s1 ... PRas3..PR6s9 W*6 M g F

O '

• % -h l w .~.. ,.-H I$

~ \

1 R

~

f >

8,,

, mi. u \*te-D in l f I I 9 I I $ I l I I f I 1 1 I I $ 1 0 0.3 0.6 0.9 1.2 1.5 <

X18 Time (sec)

W GCM 9 0 Ot t M 'O 17 M i i

MGURE 24

8*3 Ww e ecc s;a*?e* s.= y, .x ;,,,,a

• • . s et 9 " lie 23 999

. 3:*-c vsw *scrc 2 :.~ sce rs s 22 si m 3,es RCS Liquid Temperatures (F) g TL2s8 TLisi TL5s1.TL3 R

es C -

St -.... . -

, p..t 76 H t g - .

i

..i,

- t

• /

~

_,.,'~.;~__,

l. ,

$ '--._._._.i W

u ,, , t , , , , t ,,..i,,,,i,,,,

0 0.3 0.6 0.9 1.2 1.5 X18 Time (sec)

W QCNC 10 C'S$99 90 97 M I

i i

I i

1 1

MGURE 25 1

I 1

$ Mcso 4 ses:a* e* s.: a*:-X ".,ase 4A

.see s u sa ns .

,: -: vow 4.,er e a :. .4 :c as s n e c? w t

Vessel Levels (ft) g-LL2s2 LL1s1_. .LL3

.n -

m -

7 _ _ _ _ _ _ _ _\ _ _ _ _ _ _\-_ _ _ _ s

~

R - \

_  : \ _.

E. .

e o

e -

..s.- ...

• • e Q t 1 1 1 t 1 1 I I e a n a t t a e A 0 0.3 0.6 0.9 1.2 1.5 X18 Time (sec) w SCtwC i 0 St@tet to 17 M 1

E e

MGURE 26

s w 4 mesen:- re-s : u

~see s ou cs 20*aic Veamon c.g;r2 2 3.~4 04:25 's 23 31 CT *tta RHR System Vapor Volume Fractons AV22 AV23 AV24 AV25 AV27

====****%. a... - e e se

'  ! i k' ..

e :., g: ..a s

ao , d ab\ '

o -

g p ..

- i f l, - 1 {' '*h(; ..~...

l

., ~**q..**~l  ;

9l r_ i ~ -,.pn m

o . ,

t  ;

. i...- i

. it I

c -

g w li' o -

l l

[ t

. if I cv - I d

o -

~

e i

i l

f-s ,

,,,,I J,, t ,,,,t , , , . t , ,

. m ,

0 0.3 0.6 0.9 1.2 1.5 X1E Time (sec)

, eme , e eie. .e o u FIGURE 27

8 l wee. a ec gce-t 8 e*:-X *dse 64

. *%8ec 8 " 2420 791 s: e vow wvr:2: a oc:as s as:s g:t.9u RHR System Vapor Voiume Fra: pons AV28 AV29 AV30 AV38 6

ao - g ,,

o - q, ~ ~ .,_

e i

s '., _-

9_ .

s ,

. - .e a - e

" :1

u. -

m -

8

. g3

- s

- 1 W

a

~

- t.

4 t ._ i i,,,,t ,,.,i.,,.

o ,,,

1.5 0 0.3 0.0 0.9 1.2 XIE Time (sec) w SctWC 9 0 C199 96 $c 't M l

i l

MGURE 28

--a i

i l

• 8:1 vece a cet e a** e? 3 8 r8-3 :ees sa

.8ec 4 ~ se s ess

. 2: -: .se apris: :cn 4:n: cv m 1

CCP A Suction Void Fra:t:en A

- l a

o .

4 b -

. f i

1 I n  :

so _

~

h o .

cn .

o ' i .,,,i,,,,i, ,,

0 0.3 0.6 0.'J 1.2 1.5 X18 -

Time (sec)

. x x ,e 3, ,, ,e ,, a i t

P

?

b f

f 6

FIGURE 29

i

\.

. . . . . . . . , , . . - = = , , - -u 4

t..g;L""i" a

.:cu sn:,n:, su t

t RCS Pressures (psia)

PR3 PR2s2 PR5s1. P24s3 F26s9 R, _ . _ _ _ . . . . . . - - - - - -  !

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g .

g e , , ,  ! , i e i  ! '

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~

Tim (sm)

, we . , ,. w, 0 .s l

I i

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MGURE 30

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- 8:3 wee a oce ts c.fr **8 cc-I ~4ee 3A a ".e .c 3 ' u it 995

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RCS LQad Temperatures (F) t T TLis1 TL5st. . TL3

. g L2s4 _ _ _ . . . . .

g.

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t C I h .... .. .. . .

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g

~

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s I f f I f f i s 1 1" '1"  ! t t e s M f f 0 0.3 06 0.9 1.2 1.5 X18 Time (sec)  ;

w Ge%c

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.=. . .

an y:., 4 : ::c .-:-: r:- 04s, 24

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4 .

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i i

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I FIGURE 32  :

i I

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AV28 AV29 AV30 .AV38 -

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I g I 1 I I I I O 03 06 09 1.2 1.5  :

t X1E i Time (sec) i i

w it'we a e  ?*1046 il t' al >

l t

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t

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t i

l RHR System Vapor Volume Fra: tors I

AV22 AV23 -.

AV24. AV2B Av27

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't i

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rnn. < c) i ,

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FIGURE 34 i

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l i-

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i FIGURE 35 9

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r

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4

• 801 Mese a cer r e? s.: ene *K. Oase 12A we+ ot o 3 J c x Ms 2: ..c v.w ::$:r4 :.% oe:as is as et et iew ,

k RHR B Su: tion Void Fraction i R ,

E a .  !

E _

o .

5 8

R -

C '

R E 6 : '

f o .

f f I l 1 l I I E I f f f f i) 0.3 0.6 0.9 1.2 1.5 X18 Time (sec) r w SCNC 10 Oi/3096 't ft es b

J r

1 r

I i

9 FIGURE 36 i

i i

P

sCS theer 4 eos sem we a ,.sare wX. *m '4 8a8ee'SsOtGJ42*106

. *C*aiC

. woon wgoes 2 0 T m Oct M G 22 01 EDT 1984 RCS Pressures (psa) ,

PR5s1 PRAs3 PA6s9 g PR3 PR2s2 .

t I t

l 1 g ....._,

1

< y

$ 1 =~ -:.-- k g _

\

g a

~

2 _ ~

LV

! " , , , t ,,,,t , , , ,  ! , , , , I , , , ,

0 0.3 0.6 0.9 1.2 1.5 X18 Time (sec) w w w so = mme t

FIGURE 37

. 80s Woom a ser set e.e 8*8 re"I :ase *2C 8* 8ee

• 09 29 43 'sel 30*- C ve sen WyoM 2 0 4 Oct 25 'I 23 C1 ET toes RCS Ugud Temperatures (F)

TL2:8 TL1st TL5:1. TL3 1 3n _ . . . . . . - - . .

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G

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" 8

+.

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,_ $1 .  !. .o(

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l ",,,,t ,,,,I u, ,it , ,e/ I , , , ,

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. ww e ...

6 FIGURE 38

• :s wee. s oce see, rases-I :sse W

• • 8eo

ensa ses *

' ,0*wC ve mon wqerac 2 3.* e Cet 2f *! 23 01 CT '994 I'

Vessel Levels (ft) I Lus2 LL1st LL3 g- _ _ . . .

. i

_ _ I

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g I

R _

t

. i '

s-.

E  :

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em main in un...... ... . .,

N in. s so

.,+=. .

g , i n e a r t t it i f 8 8'"I A I E E I 0 0.3 0.6 0.9 1.2 1.5.

X10' Tme(sec) <

. we , . me.w . n u  :

f i

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i i

FIGURE 39

• a e

l

3see

• - w ee 4 ar

:ss o,ccr r+s ever : rc-r :me*20

. ,: - C vew wierc 2 : *m Cc:25 *t 23 :1107'ess RHR System Vapor Volume Fractions .

AV22 AV23 AV24 AV25 AV27

...~,,,,,-

, * ~~~ ~e',v,,~ ; ja,._ ' ~ ~ ~ ,

[I#'gij,y ,y\

i o .- -

i

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o "' I " ' 1 "I 'I ' ' ' ' I *?1 0 0.3 0.6 0.9 1.2 1.5 X1E Time (sec)

. w e .. ..

i I

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l l

FIGURE 40 l l

1

- I

s woe,4 ceserer

• rs-x :ase *2C

8 **e *::s as *e ses

. - 3:*-: vew *1:rc 2 : *.* :k:25 5 22 0' CT tow w amf -

RHR System Vapor Volume Fractions AV20 AV29 AV30 .---.

AV38

. 1

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

o -

l<,. i- t .

. , 1

- .i 4  ;  ;

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= i i i o - * . l ,

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, . .'~...

o -

il 1

ew ,

o = .

. .I

. ", ,I ', , f , , , t , , , , t , , , ,

1) 0.3 0.6 0.9 1.2 1.5 X18 Time (see)

. we in mene ,

b s

4 MGURE 41

e- -

I o-

'.- 3:t wesi e sco seine *** re-r :ese *20 1,* 8ee *2 *t 27 23 Hf 2: , vow ws:rc 2 : *4 cetas is 23 01 E T'994 RHR B Sucton Vec Fraction ,

R 5 i' a .

. 1 El j o .

\

T

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R " I 81 5 . .

] ..

2 -

h o

1 ci .

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o ,

0 0.3 0.6 0.9 1.2 1.5 X18 x l Time (sec) w oewc io m es a os e as r

0 FIGURE 42

r 4.

.f.

Attachment 3 to NE 95-0043 PageIofI '

l VENDOR CALCULATION PACKAGE LISTING l WCNOC Vendor Westinghouse Title Description ,

Calculation No. Calculation No.

XX-X-003 CN-CRA-94-208 Modeling the Wolf WGOTHIC model i Revision 0 Creek Mode 4 Loss with simplified of RHR Event with header volume WGOTHIC. model, no RHR t heat exchanger model.

XX-X-003 CN-CRA-94-208 Modeling the Wolf WGOTHIC model Revision 1 Creek Mode 4 Loss with detailed header of RHR Event with volume model and WGOTHIC. RHR heat exchanger model.

k

- _ _ _ _ _ _ _ _ _ _ _ _ .