NUREG/IA-0176

S4 ) International 

Agreement Report 

Post-Test Analysis of 

P5 Experiment in PANDA Facility 

With TRAC-BF1 Code 

Prepared by 

J. Polo*, S. Chiva**, J. L. Munoz-Cobo** 

*CIEMAT 

Avda. Complutense 

22 28040 Madrid 

SPAIN 

"**Department of Chemical and Nuclear Engineering 

Polytechnical University of Valencia 

Camino de Vera, 14 

SPAIN 

Office of Nuclear Regulatory Research 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001 

March 2000 

Prepared as part of 

The Agreement on Research Participation and Technical Exchange 

under the International Code Application and Maintenance Program (CAMP) 

Published by 

U.S. Nuclear Regulatory Commission
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NUREG/IA-0176

International 

Agreement Report 

Post-Test Analysis of 

P5 Experiment in PANDA Facility 

With TRAC-BF1 Code 

Prepared by 

J. Polo*, S. Chiva**, J. L. Munoz-Cobo** 

*CIEMAT 

Avda. Complutense 

22 28040 Madrid 

SPAIN 

**Department of Chemical and Nuclear Engineering 

Polytechnical University of Valencia 

Camino de Vera, 14 

SPAIN 

Office of Nuclear Regulatory Research 

U.S. Nuclear Regulatory Commission 

Washington, DC 20555-0001 

March 2000 

Prepared as part of 

The Agreement on Research Participation and Technical Exchange 

under the International Code Application and Maintenance Program (CAMP) 

Published by 

U.S. Nuclear Regulatory Commission
I

TABLE OF CONTENTS 

A CR ON Y M S ............................................................ 2 

Post-Test Analysis of P5 Experiment in PANDA Facility with TRAC-BF1 Code .......... 3 

1. INTRODUCTION ...................................................... 4 

2. The PANDA Facility and Tests ............................................. 5 

3. TRAC-BFI Model for PANDA ............................................ 7 

4. M ain R esults ........................................................... 8 

5. C onclusions ............................................................ 9 

6. R eferences ............................................................ 10
2

ACRONYMS 

ALWR: Advanced Boiling Water Reactor 

BWR: Boiling Water Reactor 

CIEMAT: Centro de Investigaciones Energeticas Medioambientales Tecnol6gicas 

DW: Drywell 

ESBWR: European Simplified Boiling Water Reactor 

GDCS: Gravity Driven Cooling System 

IC: Isolation Condenser 

KEMA: Keuringsdienst Elektrotechnische Materialen 

LOCA: Loss-Of-Fluid Accident 

MSL: Main Steam Line 

MSLB: Main Steam Line Break 

PANDA: Passive Nachwarmeabbfiihr und DrtickAbbau 

PCCS: Passive Containment Cooling System 

RELAP: Reactor Excursion Leak Analysis Program 

RPV: Reactor Pressure Vessel 

SBWR: Simplified Boiling Water Reactor 

TEPSS: Technology Enhancement for Passive Safety Systems 

WW: Wetwell
3

POST-TEST ANALYSIS OF P5 EXPERIMENT IN PANDA FACILITY WITH 

TRAC-BF1 CODE 

Jesu's Polo 

(CIEMAT) 

Sergio Chiva and Jose L. Mufioz-Cobo 

(UPV) 

ABSTRACT 

As a part of the TEPSS project, within the last fourth Framework Programme of the 

European Union R&D activities, an investigation focused on the residual heat removal 

passive safety systems in the future boiling water reactors was performed using 

PANDA facility and the codes RELAP5, MELCOR and TRAC-BF l. The main purpose 

was to ensure the capacity of these passive safety systems under a wide range of 

different conditions and hypothesis on the availability of them as well as to assess the 

quality of some of the most commonly used codes to predict the containment response 

within a LOCA. The plant design chosen as reference was the ESBWR, which is a 

special version of the SBWR adapted to reach licensing conditions in European 

countries. 

The PANDA facility, located in the Paul Scherrer Institute (Switzerland), has been 

extensively used in the past for testing the passive condenser performance for the 

SBWR. According to the reference plant, PANDA facility was appropriately modified. 

A set of eight tests was executed covering different conditions in the containment for 

the LOCA scenario, such as asymmetric conditions for the gas distribution in the 

drywell as well as for the passive condensers availability and the effect of trapped air in 

the drywell among others. 

The assessment of codes was rather challenging, since RELAP5 and TRAC-BF1 are 

thermal-hydraulic codes usually employed in transients within the primary circuit in a 

current plant. Thus, they have a well proved response in the conditions were strong 

changes of the momentum are expected, like normally occur in forced convection 

situations associated with valves and pumps. However, in containment buildings 

equipped with passive safety systems, the expected phenomena are related with changes 

in the density, that is natural convection. In addition, some other phenomena like 

condensation in the presence of non-condensable gases are also characteristic in the 

scenario. For that reason, there were also MELCOR predictions, since this code 

incorporate containment modelling, although it has no special models for the passive 

condensers in the containment. 

The general response of all the codes was rather acceptable, being all of them able to 

predict well the overall behaviour of PANDA concerning pressure, mass flow rates and 

pool boil-off. Nevertheless, some limitations were showed regarding 3D-effects such as 

in-vessel mixing and recirculation. 

This report describes the calculations performed with TRAC-BF1 code for P5 test.
4

1. INTRODUCTION 

Within TEPSS project (Technology Enhancement for Passive Safety Systems), 

belonging to the fourth Framework Programme of the European Union, the UPV and 

CIEMAT have performed the post-test analysis of PANDA experiments P with TRAC

BF1 code. The main objective in the TEPSS project was to make significant additions to 

the technology base of advanced passive-type Boiling Water Reactors (BWR) designs 

which offer enhanced safety and improved public acceptance through product design 

simplicity and increased safety margins [1]. 

The TEPSS project has undertaken research needed to support advances in the 

following areas: 

- Improved countermeasures against pool stratification, including studies of deep pool 

thermal plumes and testing of concepts for avoiding or minimising hot, stratified 

pool regions. 

- Improved designs of containments, including tests on the passive decay heat removal 

in an advanced concept Boiling Water Reactors. 

- Enhanced aerosol removal features, including tests demonstrating that passive heat 

removal systems can act as an effective aerosol filter and that the containment decay 

heat removal is not endangered by aerosol deposition in the containment cooling 

condenser tubes. 

In all cases, experimental work has been supported by balanced analytical efforts to 

identify and understand governing phenomena, and to produce usable correlations and 

reliable analytical models. 

Within the area concerning the passive removal of residual heat, the main purpose was 

the understanding and prediction of relevant phenomena through the most commonly 

used codes. The codes used (MELCOR, RELAP5 and TRAC-BF1) performed 

calculations against a set of eight tests conducted in PANDA facility. PANDA facility 

has been widely used for testing passive systems of the SBWR (Simplified Boiling 

Water Reactor) [2]. In TEPSS project, the reference design was the European Simplified 

Boiling Water Reactor (ESBWR) [3], which is an adapted version of the SBWR to 

reach the licensing requirements in Europe. This reference design lead to the 

introduction of some modifications in PANDA facility. 

PANDA experimental facility, located in the Paul Scherrer Institute (Switzerland), is 

designed to offer, among others, data on the cooling conditions in containment with the 

so-called containment passive condenser system (PCCS). The relevant phenomena 

include the mixing of steam and non-condensable gases, the condensation of steam in 

the presence of non-condensable gases and the mixing processes and thermal 

stratification in pools. 

This work presents the main results of the simulation performed with TRAC-BF1 code 

for the P5 test. The calculation of PANDA response with TRAC-BF1 code is a 

challenging exercise. The thermal-hydraulic codes are normally used in the simulation
5

of transients where strong changes of momentum are expected, associated to the 

operation of pumps and valves. However, in the passive designs the dominant drag 

forces are due to density changes (natural convection). Thus, since the conservation 

equations are not optimised for such regimes, this kind of calculations consumes a huge 

time machine. In addition, involving phenomena as condensation in the presence of 

non-condensable gases and natural circulation makes more challenging this simulation. 

2. THE PANDA FACILITY AND TESTS 

The large-scale PANDA facility (see Figure 1) is intended to make progress in the 

investigation of passive ALWR containment phenomena and the simulation of the system 

response [4]. The PANDA facility, that is scaled 1:1 in height and 1:40 in volume and 

power compared to the ESBWR reference design, has a modular structure with separate 

vessels that represent the RPV, DW, WW including the SP, and the GDCS. The DW and 

WW are represented by pairs of interconnected vessels (DW1, DW2, and WW1, WW2) to 

better model mixing and the effects of non-uniform distribution of steam and non

condensable gases on the operation of the PCCS. Piping between the vessels represents 

important flow paths between the RPV, DW and WW, including the broken steam line 

from RPV in the DW, the main vents from DW-to-WW, the GDCS drain to the RPV, the 

vacuum breakers (VB) connecting the DW and WW and lines to and from the PCCS. The 

gas space above the GDCS pool is connected to the WW gas space rather than the DW as 

in the SBWR design. Electric heaters in the RPV are used to simulate post-LOCA decay 

heat. 

The PCCS heat exchangers and their pools are represented in PANDA at full height, 

with the number of heat exchanger tubes reduced in accordance with the 1/40 volume 

scaling. As can be seen in Figure 1, the PCC2 and PCC3 exchangers are connected to 

DW2 and the PCC 1 heat exchanger to DW 1. This arrangement provided asymmetry in 

the heat removal capacity from the DW vessels. PANDA also includes an isolation 

condenser (IC) heat exchanger with its pool, again scaled at full height with a reduced 

number of tubes. 

PANDA is designed to simulate the long-term phase of the ESBWR LOCA transient, 

beginning approximately one hour after initiation of the accident. It simulates the 

accident sequence following the rupture of a main steam line (MSL), the design basis 

accident for the ESBWR containment. Water that has condensed at the primary side of 

the IC/PCC units flows from the IC/PCC lower headers back to the RPV. The non

condensable gases and/or excess steam are purged from the condenser lower headers to 

the suppression chamber of the WWs. 

In the PANDA P-series, performed for the TEPSS project, a total number of eight test runs 

have been executed. A schematic of the PANDA P-test series is depicted in Figure 2. The 

general objectives of the P-series were to: 

"* investigate the effect of the new design on the long-term containment response after a 

LOCA; 

"* demonstrate that the decay heat removal systems operate as intended under different 

accident scenarios;
6

* provide a data base for computer code assessment and analysis of particular 

phenomena. 

For each test except P8, the initial conditions have been established on the predicted state 

of the RPV and the containment vessels of the ESBWR reference design about 1 hr after 

reactor scram. This means that the DWs were mostly filled with steam and the WW 

contained non-condensable air, whereas the system pressure was approximately 2-4 bars. 

P1/8: The P1/8 test was actually a combination of two separate tests, the P1 "Base Case" 

test, and the P8 "PCC Pool Boil Down" test. Test P1 represented a simulation of the long

term PCC cooling phase starting 1 hr after a Main Steam Line Break (MSLB) LOCA. At 

that time, the GDCS injection phase has ended and steam production caused by decay heat 

in the RPV has recovered. The break flow from the RPV was directed equally to both DW 

vessels. All three PCC units were connected to the DWs with drain and vent lines open. 

The IC was not available. The PCC pools were isolated from each other and initially filled 

with water at saturation temperature. No refilling of the PCC pools was done during the 20 

hour test. 

The P8 test ("PCC Pool Boil Down") studied the effect of low PCC pool level on the long

term PCC system performance. The test was executed as an extension of P1 and it 

provided information about the containment behaviour after the 72 hour period (no 

operator action). 

P2: The "Early Start" test objective was to provide data for the transition period from the 

GDCS injection phase to the long-term PCC cooling phase of the post-LOCA transient. 

The test was initiated at 20 mins into the LOCA, when the water level in the RPV is low 

and subcooled water from the GDCS pool is draining to the RPV, thereby suppressing 

temporarily the steam production in the RPV. The test duration was 6 hours. 

P3: The "PCCS Start-Up" test demonstrated the PCC system start-up with the condensers 

and DW initially filled with non-condensable gas, which represented the most challenging 

condition for PCC start-up. Only the two PCCs connected to DW2 were operable and the 

break flow was directed to DW2. Consequently, DW1 represented a "dead-end" volume. 

The test duration was 8 hrs. 

P4: The P4 test investigated how trapped air a DW, released later in the transient, would 

affect the PCCS performance. The air release has been simulated by injecting air into 

DW 1, 4 hours after test initiation for a period of 30 minutes. The initial conditions and the 

facility configuration were nearly identical to the "Base Case" test, P1. The test duration of 

the P4 test was 8 hours. 

P5: In the "Symmetric Case, Two PCCs Only" test, each DW had one PCC connected and 

the break flow was directed equally to both DWs. It was anticipated that in the early phase 

of the test two PCCs would not be able to remove all the decay heat from the DW. Starting 

at 4 hours into the transient, air was injected into DWI for a period of 30 minutes. The test 

duration was 8 hours [5]. 

P6: The objective of the "Systems Interaction Test" was to examine the system interaction 

between the IC operating in parallel with the PCC units. In addition, the effect of DW to
7

WW bypass leakage on the containment performance was investigated. The steam 

produced was directed to the IC and via the DWs to the three PCC units. After 4 hrs, the 

(vacuum breaker) leakage path was opened. The IC operated for the first 7 hrs only. The 

test duration was 12 hrs. 

P7: The objective of the "Severe Accident" test was to investigate the PCC performance 

under the conditions of a severe accident, where hydrogen may be released to the 

containment due to the steam oxidation of Zircaloy cladding. Only the two PCC units 

connected to DW2 were operable and all steam flow was directed to DW2, thereby leaving 

DW I as a dead volume. To simulate the hydrogen release into the containment, helium as 

a substitute was injected between 4 and 6 hrs into the top of DWl. The test duration was 8 

hrs. 

3. TRAC-BF1 MODEL FOR PANDA 

The TRAC-BF1 input deck, depicted in Figure 3, is based on a former input developed 

by KEMA Nederland B.V [6]. This model has been derived from geometrical data 

concerning the PANDA facility, as used for the SBWR. 

In the original input deck, the WW and the DW were modelled with a TRAC-BF1 3D 

component VESSEL, but the liquid-gas interface level-tracking model has important 

problems working with 3D components. Therefore, it was impossible to run a test with 

a liquid-gas interface present in the WW. Using a suitable combination of ID 

components lead to very unstable results in the level movement. Moreover, the code 

crashed so frequently during several test runs that it was decided to use a pressure 

boundary condition for simulating the WW. Therefore, a BREAK component is 

connected at the end of the discharge line. This BREAK component follows, at any 

moment, a pressure curve composed by the experimental pressure measured in the WW 

gas region including the hydrostatic head from the surface of the WW pool in order to 

simulate the WW pool behaviour. 

The BREAK component is thus a practical solution in order to run the PANDA test 

using the current TRAC-BF1 code. Therefore, it was not possible to give predictions 

about the WW behaviour, but the remainder of the PANDA values were well calculated. 

The main vents and the vacuum breaker valves were both connected to the BREAK 

component that simulates the WW. However, it was possible to model the two PANDA 

drywells by means of the 3D VESSEL component that was split into two regions 

connected by a PIPE component. In addition, a special condensation model in the 

presence of non-condensable gases was implemented in the code [7]. 

The RPV was modelled with a 1D component combination. A CHAN component 

models the electric heater. The heaters were placed at the first five cells of this CHAN 

component. The chimney was modelled by a TEE and the raiser by a CHAN and a TEE 

combination. 

Regarding the passive condensers PCC and IC, PIPE components were used to simulate 

the heat exchanger tubes and the upper plenum. The lower plenum was modelled by a 

TEE component, for simulating the separation between the steam and the condensate.
8

Finally, the GDCS was modelled by a PIPE, and a VALVE represented its connection 

to the RPV. The equalisation line was replaced by a pressure condition with the same 

pressure as the WW. 

4. MAIN RESULTS 

During the first phase of the experiment, the PCC condensers were not able to take the 

whole load and, as a result, the pressure differences between drywell and wetwell began 

to rise. This fact lead to the discharge to the suppression pool through the main vent 

lines. After four hours in the transient, cold air was injected in the drywell number one 

(DW 1), increasing the drywell pressure and producing additional discharges through the 

main vent lines to the suppression pool. One and a half-hour after, the process turned 

back to normality. 

Despite the limitations imposed by the TRAC-BF1 model of PANDA, the post-test 

results are acceptable [8]. In the Figure 4 the evolution of the drywell pressure is 

presented, which shows a rather agreement with the experimental measures. The steam 

produced in the RPV was equally discharged to the two vessels representing the drywell 

(DWI and DW2). The TRAC-BF1 predictions of the main steam line mass flow 

represent very accurately the experimental data (see Figure 5). 

Figures 6 and 7 show the feed flow to the two available PCC units, respectively. Both 

condensers began to work immediately after the beginning of the transient. The TRAC

BF1 predictions show an overestimation of the feed flow from the drywell to the PCC 

units during the first half of the transient. This discrepancy is directly attributed to how 

is modelled the WW in the TRAC-BF1 model of PANDA. As it was mentioned before, 

it was not possible to simulate the suppression pool due to the shortcomings of the 

level-tracking model of the code. Thus, since during the first period of the test the gas 

present in the drywell was vented to both the condenser units and the suppression pool 

by the main vents, TRAC-BF1 is unable to reproduce the experimental values, because 

in the TRAC-BF1 model there is no main vent lines and the whole discharge is 

produced to the condenser units. After the injection of air in the drywell the predictions 

of TRAC-BF1 show a rather good agreement with the experimental values. 

Figure 8 shows the evolution of the drywell temperature. The experimental curve 

behaves practically constant and shows a slightly increase in the air injection period, as 

a consequence of the reduced capacity of the PCC to remove the heat. The TRAC-BF1 

predictions are in an acceptable agreement excepting for the first hour, where the code 

predicts a temperature peak. This is due to the limitations of the TRAC-Bfl models 

when dealing with great amount of air in near saturation conditions inside the 3D 

components. The three-dimensional modelling of such scenario makes the code to be 

very unstable and an important quantity of extra air appears virtually. This virtual 

creation of air does not affect the drywell pressure, since it appears at expenses of the 

steam, affecting thus to the heat transfer determination. 

Figures 9 and 10 present the tube temperature evolution in the condenser units PCC1 

and PCC3, respectively. After the injection of air at four hours in the transient, the PCC 

capacity is slightly reduced, as reflects the small increase of the tube temperature. The 

trend of the PCC tubes temperature is well predicted by TRAC-BF1. However, there is
9

a temperature peak during the first hour, as a consequence of the strong increase of the 

temperature predicted for the drywell. 

Finally, Figures 11 and 12 show the evolution of the air partial pressure in each drywell, 

DW1 and DW2 respectively. The curves make again noticeable one of the TRAC-BF1 

problems when dealing with air in 3D components. In the predictions of TRAC-BF I the 

air behaves in an oscillatory way and at the beginning of the transient the code produces 

an artificial mass of air, which will affect to the heat transfer processes. The TRAC-BF1 

predictions of the air partial pressure show a strong increase at the beginning of the test. 

After this spurious of initial air mass, the code estimates acceptably the air partial 

pressure. Moreover, it is worth to note that TRAC-BF1 is able to predict the 

asymmetrical behaviour of the drywell due to the cold air injection, as seen in the 

figures, where the air partial pressure increase at four hours is more sharp in the drywell 

number 1. 

5. CONCLUSIONS 

The test P5 demonstrated that trapped air, released from the DW later in the transient, 

only affects temporarily the performance of the passive containment cooling system. 

Only two PCC units operable caused an extended main vent-clearing phase with energy 

transfer to the WW, ending up with a correspondingly higher system pressure. 

TRAC-BF1 has many problems in dealing with 3D scenarios with the presence of a 

great amount of air. This fact causes most of the discrepancies encountered in the 

predictions. However, once the phenomena associated with air disappear the predictions 

are in good agreement with the experimental results and have physical meaning during 

the whole transient. The shortcomings of the level-tracking model affect somewhat the 

results, since they affect the total water inventory of the system. A mention should be 

made of the excessive computing time, which limits somewhat the applicability of 

TRAC-BF1 to partial studies instead of integral ones. 

Therefore, the TRAC-BF1 code has passed the challenging calculation of a containment 

scenario with passive-cooling safety systems. Worth to note the good response of the 

code for determining the condensation phenomena in the presence of non-condensable 

gas, because of the new condensation model, developed by UPV and CIEMAT, and 

implemented by UPV into the code, which enhances the code capacity for such 

processes. Finally, it seems necessary the revision and improvement of some models in 

TRAC-BF1, especially the level-tracking one, in order to make the code so reliable for 

passive plants as is for the current reactors. 

The calculations have been performed in a convex machine, and the computing time 

was around a week.
10

6. REFERENCES 

[1] J. Hart et al., "Technology Enhancement for Passive Safety Systems - TEPSS", 

INNO-TEPSS(99)-D20, 1999. 

[2] T.U. Shiralkar, W.H. Layman, J.G.M. Anderson, "Thermal Hydraulic Aspects of the 

SBWR Design", Nucl. Eng. Des., 144, 213, 1993.

[3] H. Arnold, A.S. Rao, C.D. Sawyer, "Two Approaches to 

Challenge for Advanced BWR Designs", Proc. TOPNUX 

1996. 

[4] J. Dreier, M. Heggenberger, C. Aubert, T. Bandurski, 0. 

Lomperski, H.J. Strassberger, G. Varadi, G. Yadigaroglu, 

and the First Test Results", Kerntechnik, 61, 214, 1996.

Meeting the Economic 

96, Vol. 1, p 101-110, 

Fischer, J. Healzer, S. 

"The PANDA Facility

[5] M. Huggenberger, C. Aubert, T. Bandurski, J. Dreier, 0. Fischer, H.J. Strassberger, 

"TEPSS Project - Integral System Test P5 Test Report", ALPHA-823, INNO

TEPSS(98)-D1O, 1998. 

[6] C.J. Murray, "Development of a TRAC-BF1 input model for the PANDA Facility", 

KEMA NUCLEAR 40880-NUC95-7210, 1996. 

[7] S. Chiva, J.L. Mufioz-Cobo, J.M. Corberd.n, A. Escrivd, "Passive Containment 

Cooling Condenser Model Implementation in TRAC-BF1", INNO-TEPSS(97)-P3, 

UPV, 1997. 

[8] J. Polo, "Post-test Analysis of PANDA test P5. TEPSS Project (WP2)", DFN/SN

18/IF-98, INNO-TEPSS(98)-D 15, 1999.
11

PANDA

Figure 1. Comparative scheme of ESBWR and PANDA
P1 Base Case PcC2j PCC= 

MSL break LOCA + 1 hr f1J •1 

(long-term PCCS cooling phase)

P2 Early Start Pr cP=2P= 

MSL break LOCA + 20 min Ii- t•fco1 

(transition from GDCS D• 'DWZj," VF 1 1

injection to long-term s"- Jm Ir ,J 

PCCS cooling phase) -

P3 PCCS Start-up 

DW initially filled with air 

(demonstrate PCCS start-up 

under challenging conditions) 

P5 Symmetric Case, Two PCCs Only 

PCC2 isolated, 

air supply to DW later in transient 

(MV clearing phase, caused by 

reduced PCC capacity)

I t.c 

I MIL1J-C 

IDAk W2

P4 Trapped Air in DW: 

Air released during transie 

(investigation of how n/c g 

affects PCCS performance 

P6 Systems Interaction 

ICS and PCCS in parallel, 

DW1 to WWI leakage 

(is PCCS performance 

adversely affected?)

M-fm

eas

P7 Severe Accident 

All break flow to DW2, Pc= " 'Pccs 

PCC1 isolated, 

He supply to DW later in transient 

(simulation of hydrogen release 

and reduced PCC capacity)

P8 PCC Pool Boil Down 

Extension of Base Case P1, - , 

(how do low PCC pool levels affect D 

containment performance?)

Figure 2. Boundary conditions of P-tests in PANDA

12
w 

V 

I

C 

C 

a.

Figure 3. Nodalisation of PANDA with TRAC/BF1 code

13

C,

C, 

C-,
14 

3.5 

3.0 

0 

• • mp_dl Q.2.5 

STRAC-BF1 

24 6 

Time (hours) 

Figure 4. Pressure in the drywell 

0.50 

0.45 

0.40 

0.35 

0.30 

0 .25 

0.20 

0• .15 

S0.10 

o• 0.05 - mv ms1 

u. L o - • RCB1 

-0.05 - TRAC-BFI 

-0.10 

-0.15E 

0 2 4 6 8 

Time (hours)

Figure 5. Main steam line mass flow rate
0.30 mv.pl r 

-- TRAC-BF1 

0.25 

0.20 

a) 0.15 

0.10 0 

L. 

0.05 

0.00 

II , ,I 

0 2 4 6 8 

Time (hours) 

Figure 6. PCC 1 feed flow rate 

0.25 

0.20 

"0.15 

0.10 

mv._p3f 

o -- TRAC-BF1 

L. 0.05 

0.00 

II , ,I 

0 2 4 68 

Time (hours)

Figure 7. PCC3 feed flow rate

15
16 

160 I 

mtg_dl.6 

15o0 TRAC-BF1 

O 140 

I- 120 

110 

024 68 

Time (hours) 

Figure 8. Drywell temperature evolution 

10 

S120 

V 110 

M. mtg..p1.7 

a) 100 TRAC-BF1 

I-.

90 

80

0 2 4 6 

Time (hours)

Figure 9. PCC 1 tube temperature
17 

Ii I i 

140 

130 

& 

S120 

mtgp3.7 C. E 11o --- - TRAC-BF1 

4) 

1

100 

90 , I , 

0 2 4 6 8 

Time (hours) 

Figure 10. PCC3 tube temperature 

0.4 , 

mpg_dl.3 

TRAC-BFt 

0.3 

(. 

'_4 0.2 

fn 

07 

5D 

o3 0.1 

0.0 

II , 

2 4 6 8 

Time (hours)

Figure 11. DW1 air partial pressure
0 2 4 6 8 

Time (hours)

Figure 12. DW2 air partial pressure

0.4

18

0.3 k

--- mpgd2.3 

-. TRAC-BF1

(U 

-o 

a) 

1

Ed, 

Ed, a) 

10

0.2 .

0.1 K

0.0
NRC FORM 336 U.S. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER 

(2-89) (Assigned by NRC, Add Vol., Supp., Rev., 

NRCM 1102, and Addendum Numbers, If any.) 

32M, 3202 BIBLIGRAPHIC DATA SHEET 

(See imbrucons on thervereNe) 

2. TITLE AND SUBTITLE NUREGIIA-0176 

Post-Test Analysis of P5 Experiment in PANDA Facility 3. DATE REPORT PUBUSHED 

With TRAC-BF1 Code _._DATEREPORT__UBLSHE 

MONTH YEAR 

March 2000 

4. FIN OR GRANT NUMBER 

5. AUTHOR(S) 6. TYPE OF REPORT 

J. Poloe, S. Chiva**, J.L. Munzo-Cobo* Technical 

7. PERIOD COVERED #ndwusive Dals) 

8. PERFORMING ORGANIZATION - NAME AND ADDRESS (f N~RC, Provide Division, Oflroe or Region, U.S. Nuclea Regulatory Commission, and ilit address; if conbnhi, 

provide name and mailing addrass) 

*CIEMAT *"Department of Chemical and Nuclear Engineering 

Avda.Complutense Polytechnucal University of Valencia 

22 28040 Madrid Camino de Vera, 14 

SPAIN SPAIN

9. SPONSORING ORGANIZATION - NAME AND ADDRESS (ffNRC, type "Same as sbove'; iffoonbacto, provide NRC Division, Offros or Region, U.S. Nuclear Regulatoay Commission, 

and mailing add*ss.) 

Division of System Analysis and Regulatory Effectiveness 

Office of Nuclear Regulatory Research 

U.S. Nuclear Regulatory Commission 

Washinaton. DC 20555-0001

10. SUPPLEMENTARY NOTES

11. ABSTRACT (200 wonrs orl•ss) 

As a part of the TEPSS project, within the last fourth Framework Programme of the European Union R&D activities, an 

investigation focused on the residual heat removal passive safety systems in the future boiling water reactors was performed using 

PANDA facility and the codes RELAP5, MELCOR and TRAC-BF1. The main purpose was to ensure the capacity of these passive 

safety systems under a wide range of different conditions and hypothesis on the availability of them as well as to assess the quality 

of some of the most commonly used codes to predict the containment response within a LOCA. The plant design chosen as 

reference was the ESBWR, which is a special version of the SBWR adapted to reach licensing conditions in European countries. 

The PANDA facility, located in the Paul Scherrer Institute (Switzerland), has been extensively used in the past for testing the 

passive condenser performance for the SBWR. According to the reference plant, PANDA facility was appropriately modified. A 

set of eight tests was executed covering different conditions in the containment for the LOCA scenario, such as asymmetric 

conditions for the gas distribution in the drywell as well as for the passive condensers availability and the effect of trapped air in the 

drywell among others.

12. KEY WORDS/DESCRIPTORS (Lst words or phrases that wX assist meem.mvs in /ocaUng ffe repor) 13. AVAILABILITY STATEMENT 

TRAC-BF1 unlimited 

BWR/6 14. SECURITY CLASSRCATION 

ATWS (-is Pae) 

MSIVC unclassified 

Kinetics (Tis Report) 

unclassified 

15. NUMBER OF PAGES 

16. PRICE

NRC FORM 335 (2-89)
Federal Recycling Program
POST-TEST ANALYSIS OF P5 EXPERIMENT 

IN PANDA FACILITY WITH TRAC-BF1 CODE

UNITED STATES 

NUCLEAR REGULATORY COMMISSION 

WASHINGTON, D.C. 20555-0001

MARCH 2000

SPECIAL STANDARD MAIL 

POSTAGE AND FEES PAID 

USNRC 

PERMIT NO. G-67

NUREG/IA-0176