ML20198G235
| ML20198G235 | |
| Person / Time | |
|---|---|
| Issue date: | 03/18/1986 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2391, NUDOCS 8605290313 | |
| Download: ML20198G235 (47) | |
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DATE ISSUED: 3/18/86 ACRS ECCS SUBCOMMITTEE MEETING MINUTES JANUARY 23-24, 1986 PALO ALTO, CA PURP g : The purpose of the meeting was to continue the Subcommittee's revi v of the joint NRC/B&W Owners Group /EPRI/B&W Integral System Test (ISTi Program and related Programs.
ATTdlDEES:
Principal meeting attendees included:
ACRS NRC Dard, Chairman E Lee J. Ebersole, Member W. Beckner H. Etherington, Member C. Michelson, Member University of Maryland C. Wylie, Member Y. Y. Hsu I. Catton, Consultant V. Schrock, Consultant EPRI C. Tien, Consultant D. Sursock T. Theofanous, Consultant P. Boehnert, Staff INEL T Tarson B&W C Carter LANL J. Klingenfus T"Tnight SAI A. Hashemi The Meeting was convened at 1:15 p.m. on January 23, 1986.
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1.
Mr. R. Carter overviewed the status of the MIST facility Project.
I He detailed the results of the facility debugging which was com-pleted in mid-December. Problems encountered during debug were discussed (Figures 1 and 2).
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ECCS Meeting Minutes January 23-24, 1986 Currently, the MIST facility is beginning characterization testing (Figure 3).
In response to Mr. Michelson, B&W has tests planned to characterize the behavior of the reactor vessel vent valves for both vapor and liquid conditions.
A set of candidate tests were described of which a number (4) would be selected for the tests listed as " undefined" in the current matrix (Figure 4). A set of undefined tests was included in the original matrix to address issues for which further definition was required.
The status of the critical instrument designations for MIST and the feasibility and cost of a feed and bleed (F&B) test was noted. The F&B test can be run on MIST with a relatively minor cost increase
($60-86 K). As a result of Subcommittee questioning, Mr. Ward indicated that the modeling of the pressurizer flow diffuser should be a key concern in simulating a long-tenn F&B cooling test. B&W was not certain if the MIST diffuser was prototypic of the full scale plant. At Mr. Ward's request, B&W said they would check on this item and respond at a later date.
2.
W. Beckner (RES) overviewed the status of the MIST follow-on Program. He indicated that budget reductions threaten this Pro-gram.
Independent of budget considerations, NRR & RES have defined a list of specific test needs. This information will be used to set a priority for data needs. Dr. Beckner indicated that the MIST follow-on is of interest to the new EDO (V. Stello). In response to Mr. Michelson, RES said the key uncertainties with the follow-on Program are the major; facility modifications required and whether industry support will,bi' forthcoming. Dr. Catton reconsnended postponement of the follow-on decision until data from UMCP & SRI are available.. 'RES said that to wait is.to probably lose continu-ity with the B&W support effort.
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s ECCS Meeting Minutes January 23-24, 1986 In response to Mr. Ward, Dr. Beckner said if the follow-on program is not conducted the state of T/H understeriding for 08W plants will not equal that of W and CE plants vis-a-vis Semiscale, LOFT, etc.
Dr.Y.Y.Hsu(bniversityofMaryland)reportedtheresultsof 3.
tests run at the University of Maryland facility (UMCP) to date.
Test results were shown for four areas:
(1) primary-secondary interaction, (2) depressurization simulation, (3) RVVV scaling and natural circulation, and (4). hot-leg phase distribution. Mr.
Michelson asked if the atypicality of the high point vent on the pressurizer (it is higher than the hot leg U-bend) will affect the test results. Dr. Shu said he didn't believe it will significantly impact the results.
For the primary-secondary interaction tests, key conclusions are given on Figures 5-6.
For the natural circulation tests, the objectives were to check for asymmetric behavior and the system response to a power transient.
J Key conclusions from the NC tests were:
(1) all power transients show same response with symetrical behavior in primary system, (2) no flow instabilities were seen (flow reversal, etc.), (3) thermal and fluid dynamic effects are uncoupled and thermal response is i
much slower than the fluid dynamic response, (4) thermal and fluid
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mechanic behavior can be described properly by theory, and (5) analysis is still ongoing (SG shell temperature distribution, thermal center, heat loss, etc.).
1 The RVVV tests showed that the UMCP RVVV's show a Ap lower than B&W prototype RVVV's due to the lack of hydraulic flow resistence in the primary loop because there are (as of now) no pumps in the system.
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s ECCS Meeting Minutes January 23-24, 1986 fiapid depressurizatien tests yield the following conclusions:
(1) the licaid invertory time behavior is reasonably in agreement with thecalcuist.edvaluesforbreaksizesintheorderof0.1 inch,(2) the phenomena takes place 'in "real time" compared to the TRAC calculations, and (3) all the experimental data (regardless of break size) can be collapsed in a " pressure ratio versus void" rep-resentation and are in good agreement with the calculated values; thus yoid can be considered es.a time scale. Mr. Michelson seid point 3 is only tree as lcag as the system is maintained subcooled.
Four areas are under study for the UMCP analysis effort. These cre: (1) system modeling for natural circulation, (2) RELAP-5 stoping calcul6 tion for BC'i condition, (3) a simplified equation for two-phase critical fitw, and (4) continuing work on pressure-modeling and size scaling.
Figare 7 outline the overall analysis
- scheme, figure 8 gives the current facility status, A.
The status of the ANL hot leg U-bend two phase flow studies was given by R. Lee (NRC-RES). The objectives of this work are to:
(1) Develop two-phase flow scaling criteria, and (2) Study of the hog leg U-bend including U-bend flow interrupt)Dn and reest3blish-ment, and evaluation of hot leg flow regimes.
Figures 9 and 10 gives the details of the experimental programs.
Figure 11 shows the status of these experiments Figures 12 and 13 give a set of preliminary results from the tests to date, t
Mr. Ward noted that the significant result seems to be that perma-nent flow interruption is gover.ned by the head balance in the two hot-legs and that ph'se separation is not the cause of flow inter-a ruption at the hot leg U-bend. RES said these conclusicas need to be recenciled with data from SVt! and other studies.
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e ECCS Meeting Minutes January 23-24, 1986 5.
J. P. Sursock (EPRI) discussed the joint NRC/EPRI report on the coordination of the support projects for the IST Program.
Figure 14 lists the various support Projects covered in the report.
Sursock believes the Report will assure a synergetic effort such that virtually all TAG issues will be resolved.
Mr. Ward stated he was impressed with the Report and that this indicates a good job of coordination has been done. Mr. Sursock said that an updated Report will be issued which will include the "as-built" status of the test facilities.
Mr. Ward indicated discussion of the use of the RELAP code is missing. EPRI said the focus of the Report didn't include RELAP.
Dr. Sursock said discussion of RELAP will be considered for the updated Report.
Dr. Sursock provided clarification of remarks he made at the June 12-13, 1985 ECCS Subcommittee Meeting regarding use of stability analysis in modeling loop-to-loop oscillations at the SRI-II facility.
6.
A. HasPemi (SAI) discussed the results to date of two-phase flow regime studies for the hot leg U-bend. The objectives cf this work were to:
(1) characterize two-phase flow regimes in a candy cane hot leg geometry, and (2) to measure flow carryover as a function of collapsed liquid level.
Figures 14 A and B show the test facility details. The SAI work indicates that the flow regimes in the scaled facilities can be extrapolated to a full scale plant provided one pays close attention to the flow regime test parameters used.
7.
D. Ward solicited Subcorraittee comment on the coordination Report noted above.
H. Etherington expressed his approval. Dr.
ECCS Meeting Minutes January 23-24, 1986 Theofanous was pleased with the documentation produced and eagerly awaits the test results. Dr. Tien said there is more " coordination at the top" but feels more interaction at lover levels in each program would be helpful. He also would like to see more pre-test analysis for each test Program as well. Mr. Schrock agreed with Dr. Tien and said that there is a need for more education in the scaling area, particularly in the area of constitutive equations, to assure that extrapolation of the test results to the full scale plant is successful. Mr. Ebersole expressed concern that for B&W plants we should focus on the impact of secondary upsets and the resulting use of the PORV, particularly to feed and bleed. Dr.
Catton expressed approval of the coordination of the test data and expressed concern with the extrapolation of the test data via use of " frozen" codes that have known defects (RELAP-5 and TRAC).
8.
T. Larson (INEL) provided the status of the Report on the IST scaling study. The study's objectives include:
(1)documenta-tion / description of IST Integral facilities (including scaling philosophy, design and geometric parameters, limitations, and scaling artlysis, (2) provide insight on relating facilities and data produced, and (3) provide insight on " counterpart" testing for assessment of scaling / phenomena. Figure 15 outlines the Report's contents. A draft of the Report was completed in late December and distributed to the Subcommittee. Comments on the draft are welcome until February 10, 1986. A final version will be published in March 1986.
The results of the INEL scaling study were described. Key points noted included:
In response to Mr. Ward, Mr. Larson noted that the volume scale in some of the facilities (e.g., MIST) is distorted (i.e., the scale factors are ideal values).
V. Schrock asked
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4 ECCS Meeting Minutes January 23-24, 1986 if the scale distortions have some rationale. Further dis-cussion showed that there were many compromises in the scal-ing. Drs. Catton and Tien said that the impact of the scaling distortions needs to be addressed in more detail in the Report. Also, one needs to determine how the codes will accommodate these distortions. Mr. Larson and NRC solicited Subcommittee coment on this and other issues for the draft Report.
Mr. Larson noted the limitations and atypicalities for the facilities that are of key concern. These include power, J
pressure, and comparisons of actual to ideal conditions for such parameters as geometry, elevations, hydraulic resistance etc.
Mr. Ward asked if INEL had looked at the raised loop vs lowered loop issue. Mr. Larson said the GERDA and OTIS data will be used for this item. Mr. Ward said this issue should be addressed in the INEL Report.
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- Key conclusions of the scaling analysis included:
(1)there i
should not be any significant distortions in the hot leg flow j
regimes in any of the integral facilities; (2) flooding dis-tortions will be seen in the hot legs if th.a RVVV's are frozen shut; (3) pressure drop will scale well if critical parameters are maintained in proper scale; and (4) there will be excess subcooling if the HPI water is not heated in the low pressure facilities. Concerning Item (1) above, the Subcom,ittee noted thisconclusionisforsteadystateconditionsonifandin efftet is a " snap-shot" of conditions and that this point should be investigated over a wide range of flow conditions including transients. Mr. Larson indicated he will look into this point and address it in the Report.
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ECCS Meeting Minutes January 23-24, 1986
- General conclusions noted by Mr. Larson that were not dis-cussed above included:
(1) all IST facilities are generally well scaled and the facilities are related by general scaling criteria; no significant local phenomena distortions are expected; cold leg mixing is strongly dependent on HPI tem-perature; pressure can be scaled through property groups, (2) single-phase and two-phase scales discontinuities are expected for reduced pressure operation, and (3) use of two-phase power scale is recommended to avoid discontinuous power changes.
- Mr. Larson recomends that the MIST mapping tests provide the best tests for counterpart test comparisons with the SRI and UMCP facilities. A transient counterpart test recommended by INEL is the MIST 310000 nominal mapping transient test.
In the end however, INEL believes trial and error will be neces-sary to find the best method of test conduct for counterpart test comparisons among the three facilities.
Dr. Y. Y. Hsu provided some comments on the UMCP scaling philosophy that took exception to some of Mr. Larson's approach (Figures 16-17).
9.
The status of the, TRAC code support for the IST Program vas given by T. Knight (LANL{. Key points of his presentation included:
Addressing the issue of modeling of the steam generator tube wetting issue in both TRAC and RELAP-5, Dr. Knight noted the following:
(1) TRAC tends to force more of the heat transfer down toward the pool (water level in the SG) relative to RELAP-5; the effect of this shift in heat transfer is to lower the primary-side thermal center in TRAC relative to RELAP-5 (the thermal center in the core is not affected because the j
axial power distribution is fixed through input.), (2) because
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ECCS Meeting Minutes January 23-24, 1986 of the reduced thermal-center elevation in the TRAC steam-generator primary side model, the code produces lower primary flows in natural circulation, and (3) LANL proposes making no changes in either code until MIST produces data indicating the correct system behavior; at that time more separate-effects data may or may not be needed to produce a superior AFW wetting model.
In response to Dr. Catton, Dr. Knight said the TRAC wetting model has deficiencies. Dr. Catton urged LANL to obtain ORNL data that could help improve the wetting model.
Mr. Schrock urged LANL to fix the model given the known deficiencies for the sake of correct physics. NRC noted that the codes are now frozen in order to get a handle on code assessment. NRC said the above deficiency will be corrected in the future after the assessment period is over. The Subcommittee agreed that using a code with wrong physics is poor practice and should not be continued. LANL indicated that these types of problems will be addressed within the con-straints of budget.
Results of noding sensitivity studies show that:
(1)in-creaseddetailednodingintheupperplenum(UP)doesimpact the results. LANL is investigating use of multi-dimensional noding for the UP; (2) noding sensitivity studies of the cold-leg injection and mixing in OTIS revealed a minimum acceptable noding (one cell between the injection point and the downcomer). TRAC noding of MIST is consistent with this finding, (3) two-channel modeling of the OTSG - the results j
from the TRAC OTIS analyses show the importance of better I
representing the flow field and heat transfer in the OTSG secondary; calculational resolution of this problem will require at the very least multi-dimensional models, and (4) one-dimension vs three-dimension MIST downcomer behavior -
LANL did not observe any significant three-dimensional i
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ECCS Meeting Minutes January 23-24, 1986 behavior in the flow field calculated with the three-dimensional vessel component.
Results of the TRAC pretest calculations of the MIST nominal test were shown.
Figures 18-21 provide details.
- 10. The status of the RELAP-5 code use for the IST, and some calcula-tional results, were described by J. Klingenfus (B&W). Details of the RELAP code version used, including additions and changes made by B&W, are given in Figure 22.
Figures 23-24 describe the analy-ses performed with RELAP-5 to date. B&W discussed the analyses of OTIS test 230299 and MIST test 340302.
2 The OTIS test was a scaled 20 cm cold leg suction break which was isolated after 30 minutes.
Figure 25 provides details. Figure 26 shows the RELAP noding scheme for the test. Comparison of the code results with data (Figure 27) shows good agreement. B&W's con-clusions for the test are shown on Figure 28 - B&W believes the code gave a good prediction of the test data.
The LIST pretest prediction for test 340302 (scaled 10-15 tube SGTR) was described.
Figures 29-31 show the details. The results show core cooling is maintained throughout the event.
11.
W. Beckner discussed the plans to assure effective overall coor-dination of the IST analysis effort. He showed the pre-test calculation matrix for MIST using the TRAC, RELAP-5 and RETRAN (EPRI) codes (Figure 32). A matrix for post-test calculations will be developed in the future. LASL will also develop TRAC code decks for UMCP and SRI-II. NRC will also be doing sensitivity studies in-house.
In response to Dr. Tien, NRC said they will not do pre-test calculations for UMCP and SRI-II, only post-test
ECCS Meeting Minutes January 23-24, 1986 calculations will be done.
Dr. Hsu said UMCP scoping calculations have been done.
Dr. Beckner solicited Subcommittee coments on the INEL scaling study before February 10, 1986.
Mr. Ward said the Subcommittee had requested information on a sensitivity study on the SG tube-wetting phenomenon. NRC said the codes are now " tuned" to a 10% wetting value (i.e., 10% of the tubes are assumed to be wetted by the AFW spray). RES is inves-tigating the sensitivity of this assumption but won't have the results for sometime. Mr. Ward said this is a potentially serious problem and should be addressed expiditiously. RES said separate effects studies may be needed to resolve this issue.
- 12. The Subcommittee discuss-future activities.
Key points of the discussion are noted be' i.
Mr. Ward said that futu.e RES funds for T/H is on a decreasing j
slope. This will result in a decreasing level of effort. The ACRS is tasked with advising the Commission on how this T/H effort should be directed. Mr. Ward wants the Subcommittee to channel its efforts to defining what critical issues need to be addressed, given the above. Mr. Schrock felt that the severe core damage research has resulted in compromising the T/H programs. He said the Subcommittee should have strong input to the decision process as to where the funding should be spent. Dr. Theofanous said one should set a priority on the issues to be addressed and then tackle them as resources permit.
Dr. Theofanous suggested the Subcommittee Members and Consultants develop an outline of how to address this issue of future efforts and go after it in an organized fashion instead of a round-table
ECCS Meeting Minutes January 23-24, 1986 discussion. The Subcommittee should attack the issues in a goal-oriented manner with a clear end point in mind. He is concerned that many topics and issues seem to be turned off before they are fullyconcluded(i.e.,LBLOCA,hydrodynamicloads,etc.). There-fore, no orderly conclusion is given to these and other issues.
Dr. Tien recommended that the Subcomq1ttee should address issues such as research budget allocations, and priorities for safety issues, i.e., the meetings would have a wider perspective than our usual " meat and potatoes" topics.
Mr. Etherington suggested the ACRS provide a letter to the Commis-sion with recommendations in the above areas.
Dr. Theofanous said the Subcommittee did a good job in assuring coordination and integration of the IST. He said that this is the mode the Subcommittee should be in on a permanent basis. He reiterated that the current way of doing business with the incom-plete documentation provided us leads to constant re-opening of issues such as has been recently seen with the PTS issue. Dr.
Catton said the issue of incomplete documentation is a management problem within NRC.
Mr. Ward said he was hearing advice that the Subcommittee should be more proactive. Dr. Catton said the Subcommittee should also investigate whether NRR is getting the support it needs from RES.
Mr. Ward proposed that the ACRS should prepare a letter setting out how RES resources should be spent in future years. He suggested the Subcommittee hold a series of meetings to develop proposals for these recommendations. He said also that each Consultant and Subcommittee Member submit a five-item list of the most important l
issues that need to be addressed in the area of T/H.
From this
ECCS Meeting Minutes January 23-24, 1986 list, the Chairman said he will develop a plan of attack for a set of Subcommittee meetings.
l The meeting was adjourned at 3:10 p.m., January 24, 1986.
NOTE:
Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, 1717 H Street, NW, Washington, DC, or can be purchased from ACE-Federal Reporters, 444 North Capital Street, Washington, DC 20001, (202) 347-3700.
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[hebug FN'oblems e Conax RTD's
-- Problem: Routine GA Audit of Conax revealed that calibration results could be questionable
- Verification:
MIST spare RTD's were checked and unacceptable results were found
- Resolution:
Conax replaced RTO's and an independent lab calibrated.
New RTD's will be installed when RCP's are installed.
-- Cost:
~$20,000
r Debug Problems, Con't e Bailey BC Differential Pressure Transmitters
- Problem:
Instrumentation checks during debug indicated that 50-60 units were exhibiting excessive zero drift
- Verification:
Additional zero checks and complete calibrations have shown that the BC's are not able to maintain accuracy
.if over-ranging occurs.
- Resolution:
Replace most of the BC's with Rosemount 1151DP's.
Use the remaining BC's for less critical measurements.
- Cost :
~$60,000
MIST Testing - Characterization Activities Calendar Months 1986 Jan Feb Mar Apr May i
Guard Heater Characteritation Mi j
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Feedwater Controls ll l
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Steam Controls li i
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Install RCP's M
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i Pump Debug l
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j Fluid Volume Thermocouple Calibration
!M Irrecoverable Pressure Loss i
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i Remove Pumps i
j Mi RVVV/DC Vapor N
RVVV/DC Liquid l
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Nominal Dry Run i
i Install RCP's And Densitameters N
Active Planned Ts N
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CANDIDATE UNDEFINED TESTS i
1 Test i
1.
Feed and Bleed with PORV in i
I Auto i
2.
- AFW Variations: Maximum vs.
Minimum Wetting 3.
Nominal Repeat I
4.
SGTR: Apply Cooldown Rat.! and Tube-to-Shell Temperature Difference Limits 5.
Feed and Bleed: Operate (stop, bump, restart) RCP's based on SCM - 568 4 2/W /,wdWB' i
6.
- Alternate Leak Location: Al CLD 7.
Characterize Heat Losses with Guard Heaters Off j
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8.
Extended Mapping 9 ~.
Long Term Feed & Bleed Cooling 10.
Core Power Augmentation Test j
NOTE:
Asterisks denote tests requiring MIST modifications l
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CONCLUSIONS DRAWN FROM PRIMARY & SECONDARY SINGLE-PHASE NATURAL CIRCULATION ANALYSIS 1.
STEAM GENERATOR HEAT TRANSFER COEFFICIENT IS ENHANCED BY THE FACT THAT IN LAMINAR FLOW AND LOW REYNOLD NUMB TURBULENT FLOWS, THE WALL TEMPERATURE AFFECTS VISCOSITY TO DISTORT THE ESTABLISHED VELOCITY PROFILE.
IN ADDITION THERE IS SUPERIMPOSED LOCAL FREE CONVECTION DUE TO TEMPERATURE DIFFERENCE.
2.
FLOW RESISTANCE COEFFICIENTS, K S, ARE WEAKLY DEPENDENT ON THE FLOW RATE.
3.
SYSTEM THERMAL LENGTH, THE VERTICAL DISTANCE BETWEEN THE CORE AND STEAM GENERATOR THERMAL CENTERS IS A WEAK F OF STEAM GENERATOR LOAD.
AN INCREASE IN THE ' RATE OF SECONDARY SIDE MASS FLOW RATE CAUSES A REDUCTION IN THE THERMAL LENGTR, DUE TO THE FLATTENING OF THE STEAM GENERATOR l
PRIMARY-SIDE AXIAL TEMPERATURE PROFILE.
AN INCREASE IN THE CORE POWER WOULD INCREASE THE THERMAL LENGTR D INCREASE IN TEMPERATURE GRADIENT ALONGSIDE THE HEAT EXCHANGER.
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CONCLUSIONS DRAWN FROM PRIMARY & SECONDARY SINGLE-PHASE NATURAL CIRCULATION ANALYSIS (CON'T) 4.
IMPOSITION OF ASYMMETRIC HEAT REMOVAL INDUCES ASYMMETRIC RESPONSE IN THE PRIMARY-SIDE.
A MARKED SECONDARY-SIDE FLOW RATE UNBALANCE RESULTS IN SIMILAR BUT MUCH LESS DRASTIC PRIMARY-SIDE FLOW REDISTRIBUTION.
THIS IS DUE TO THE VARIATION OF THERMAL LENGTH AND LOOP RESISTANCE WITH THE FLOW RATE.
5.
IMPOSITION OF ASYMMETRIC HEAT REMOVAL WHILE RESULTING IN A MILD FLOW OSCILLATION, IN HOT LEG DID NOT CAUSE FLOW INSTABILITY LEADING TO CESSATION OF CIRCULATION.
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l T!!EORETICAL INVESTIGATION l
'No-Phase Single-Phase Analysis Analysis Solution Mathematical Solution Mathematical Method Model Method Model f
Implicit Conservation Contitutive Conservation Explicit Implicit Constitutive Conservation Scheme Equations Relations Equations Scheme Scheme Relations Equations l
(System)
(Pressurizer)
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3.
STATUS OF FACILITY - CURRENTLY, Tile LOOP IS UNDERG0ING FACILITY IMPROVEMENT AND MODIFICATION:
A.
DAS - SPEED UP FROM 7 Hz TO 30 Hz B.
COOLING TOWER - REPLACING LOW TEMPERATURE PVC PACKING AND SEAL BY HIGH TEMPERATURE MATERIAL (METAL, CERAMIC AND HIGH-TEMPERATURE SEAL) i C.
STEAM-GENERATORS - RE-PIPING TO ENABLE NORE VERSATILE CONTROL D.
T.C. RAKE - INSTALLED TO MEASURE PRIMARY-SIDE AXIAL TEMPERATURE PROFILE t
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EXPERIMENTAL PROGRAM (1)
LOOP DESIGN
- SCALE MODEL BASED ON SIMILARITY CRITERIA (ISHII)
- STUDY OF SCALE DISTORTION EFFECTS (2)
EXPERIMENTAL SERIES N -WATER EXPERIMENTS (I) 2
- NATURAL CIRCULATION INTERRUPTION & RESUMPTION
- DYNAMIC EFFECT (FLOW OSCILLATIONS ETC.)
- FLOW REGIME TRANSITION, VOID DISTRIBUTION & SLIP
- EFFECT OF GAS FLUX ( CORE POWER)
- EFFECT OF LOOP FRICTION
- EFFECT OF DRIVING HEAD (THERMAL CENTER) CHANGE
- EFEFCT OF INLET GEOMETRY STRAIGHT INLET HORIZONTAL HOT LEG INLET
- EFFECT OF SCALES ( AND SCALE DISTORTION)
DIAMETER LENGTH RADIUS OF CURVATURE (II) FREON-113 (BOILING & CONDENSATION) EXPERIMENTS
- SAME AS ABOVE
- EFFECT OF PHASE CHANGE EVAPORATION IN HOT LEG CONDENSATION ON DYNAMICS
- EFFECT OF FLUID PROPERTY
- MINIMUM COOLING (BOILER-CONDENSER MODE)
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HOT LEG U-BEND STUDY
- DEVELOPMENT OF TWO-PHASE SCALING CRITERIA FOR LOOP
- PERFORM SIMULATION TESTS (FLOW VISUALIZATION)
- PERFORM SCALE DISTORTION TESTS (MIST, U OF MD, ETC.,)
l KEY PHENOMENA TO BE STUDIED (1)
LOOP PHENOMENA:
NATURAL CIRCULATION INTERRUPTION AND REESTABLISHMENT FLOW INSTABILITY THERMAL CENTER LOOP FRICTION (2)
HOT LEG SECTION:
FLOW REGIMES AND TRANSITIONS i
ENTRANCE EFFECT DIAMETER EFFECT (LARGE D)
VOID DISTRIBUTION (3)
INLET GE0 METRY HORIZO:1TAL SECTION (ON FLOW REGIME)
(4)
U-BEND SECTION FLOW SliPERATION U-BEND CURVATURE EFFECT (5)
PHASE CHANGE EVAPORATION IN HOT LEG i
CONDENEATION EFFECT PROPERTY EFFECT
- DEVELOPMENT AND VALIDATION OF MODELS lf/6,Ib)
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STATUS or AHl. ExPrRilirNTs LARGER 0 Hof LEG ORAHETER 2"
4" (10 - 12")
FLulD HOT LEG HEIGHT 18' 12' 18' STRAIGHT VERTICAL INLET (1)
'(2)
(4)
N-gas FLUX (CM/sEC) 0-100 0-100 0-50 2
WATER LOOP FRICTION VALVE OPENING 1/8, 3/16, 1/4,,1 1/8, 3/16, 1/4, 1 1/8, 1/16, 1/4, 1 DRivlNG HEAD 3 LEVELS 3 LEVELS 3 LEVELS U-B CURVATURE (R/D) 1.78, 3 1.78, 3 1.5, 2.5 STATUS COMPLETED COMPLETED COMPLETED IN 2/86 HORIZONTAL HOT LEG INLET (CM) 15, 91 (3) 25 (5)
GAS Flux (CM/SEC) 0-100 0-50 LOOP FRICTION VALVE OPENING 1/8, 3/16, 1/4, 1 DRIVING HEAD 3 LEVELS U-R CtlRVATURE (R/D) 1.78, 3 1.5 Status CnMPLETED
' COMPLETED IN 5/86 PLANNED IN fY 87 HORIZONTAL hot LEG INLET (CH) 15 (6)
CORE POWER 0-2 KW FREON PRESSURE
-10 PsIG 113 THERMAL CENTER 3 LEVELS U-R CURVATURE (R/D) 3 STATUS CONSTRUCTION 5/86 TEST START 6/86 (1)
ANL REPnRT TO RE PUBLISHED IN FEB. 1986.
(2) (3) ANL REPORT TO BE PURLisHED IN APRIL 1986.
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A'il. R F P O R T To ME PilRL l % H F. D IN 1
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ANL PRELIMINARY REPnRT IN SEPT. 1986.
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PRELIMINARY RESULTS (1)
NATURAL CIRCULATION
- GOVERNED BY HOT LEG GAS FLUX i
DRIVING HEAD (SEPERATOR WATER LEVEL)
LOOP FRICTION (2)
PERMANENT FLOW INTERRUPl10 L kRNED BY HEAD BALANCE [TWO thU VOID DISTRIBUTION IN HOT LEG WATER LEVEL IN SEPERATOR (TH. CENTER IN S.G.)
i (3)
OCCURENCE OF FLOW INSTABILITY
- NEAR FLOW INTERRUPTION (LOW FLOW)
- PERIOD, PARAMETRIC DEPENDENCE (DENSITY WAVE INSTABILITY)
- EXPECTED SIGNIFICANT EFFECT ON LOOP OSCILLATI (4)
INTERMITTENT FLOW INTERRUPTION
- FREQUENT IN CAP-BUBBLE OR SLUG FLOW REGIME
- FLOW RECOVERY WITH SUFFICIENT DRIVING HEAD
- NOT A TRIGGER MECHANISM FOR PERMANENT INTERRU (5)
U-BEND FLOW
'i k _S5fERATION IS NOT THE CAUSE OF P
- LITTLEEFF5T0FCURVATUREONFLOW
~
f/6-k
=
(6)
EFFECT OF INCREASED DIAMETER
- INCREASED TURBULENCE AND GENERATION OF i
SMALL BUBBLES
- TENDENCY: TOWARD ELIMINATION OF SLUG FLOW DOMINANTLY BUBBLY AND CHURN FLOW
- THE0RETICAL LIMIT OF SLUG FLOW D4 4o
~ 10 cm
~
DYNAMICALLY MORE UNSTABLE 1
(7)
EFFECT OF INLET ON HOT LEG FLOW
- SIGNIFICANT EFFECT ON HOT-LEG FLOW REGIME STRAIGHT VERTICAL: BUBBLY-+ SLUG
- CHURN FLOW HORIZO_NTAL HOT LEG INLET: SLUG FLOW ONLY
- SIGNIFICANT AXIAL DEPENDENCE OF REGIME TRANSITIONS
- SCALE EFFECT INTEGRAL FACILITY (SMALL D):
SLUG FLOW FROT0 TYPE (LARGE D):
BUBBLY AND CAP-BUBBLY FLOW 1
l (8)
OVERALL HOT LEG HEIGHT I
- SIMILAR IN BASIC PHENOMENA
- LONGER HOT LEG
- DEVELOPMENT OF LONGER SLUG BUBBLES l
- FLOW DEPENDENCE ON LENGTH SCALE FACTOR l$ )
c PROJECTS DESCRIBED IN REPORT MIST INTEGRAL TESTS SRI-2 INTEGRAL TESTS UNIVERSITY OF MARYLAND INTEGRAL TESTS ANL FLOW REGIMES sal-1 FLOW REGIMES sal-ll.
AUXILIARY FEEDWATER TRAC-PFl/ MODI INTEGRAL MODEL TETRATECH PUMP MODEL TWO-PHASE PUMP MODEL JPS/cs/3924ST6A
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I l
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Report Content e
Progran and Fac!Ilty-Description iSTProgram j
Facility Description and'@Jectives e
Scaling Methodology Scaling Methods Facility Scaling Methods Facility Limitations and Atypicalities Scaling Evaluation e
Relation of IST Facility Results Implicottons of Operation at Nontypical Pressures
[#
^
Methodology for comportson e
"Counterport" Experiments Steady-State
' Transient o
Conclusions
,I
, W 9
)6 y Stiv nartisi
~
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SCALING RATIOS 1
THE REQUIREMENTS THAT 4/h= 1 IS T00 STRIGENT IF pd IS A PARAMETER RELATING TO REGIME MAP OR STABILITY MAP.
EG
- 1. FROUDE NO IN A REGIVE MAP CAN HAVE VARIATION IN THE RANGE OF 10 WHILE STILL BRACKET THE SAME i
FLOW PATTERN 2' N PCH SUB i
THUS AS LONG AS THEY COVER THE SAME GENERAL STABLE / UNSTABLE REGIONS, ONE CAN TOLERATE SOME VARIATION 3
- 3. IF ONE USES ZUBER'S GLOBAL SCALING CONCEPT, THEN EVEN IF N PCH SUB (N
4suB)"I' H U M N d ecH
a PRESERVED,CCFLISSC%D i
i
r THREE LEVELS OF EXPECTATION FOR INTER-FACILITY D6TA CG1 PAR.ISON
.1.
DIRECT COMPARISON BETWEEN TWO FACILITIES -
CAN ONLY BE EXPECTED FOR WELL-SCALED FACILITY WITH FULL PREESURE TEST CONDITION 2.
TRAliSLATION OF TEST RESiJLT THROUGH SCALING
- ME?HODOLOGY, SUCH AS " COMPRESSED TIME SCALE",
"P/P vs, % M " ETC.,
THE HOPE IS THAT SCALING g
g fETHODOL0EY CAN BE DEVELOPED TO ENABLE US TO PE8 FORM SUCil TRANSLATION, Ti115 IS AN ADDITIONAL, BUT M6RE BASIC MISSION GF VARIOUS REDUCED-SCALED FAtiLITY 3,
COMPARISDN OF DM A THROUGH COMPUTER CODES -
I THIS IS AN ACHIEVABLE GOAL AND IS THE BASIC EXPECTATION, WHILE " LEVEL 2s SCALING TRANSLATION" BEING AN HOPED-FOR G0AL,
~
Nominal initiai Test Conditions for MlST Test 310000 System pressure Vary to obtain 12.2 K
subcooling SG secondary pressure 6.96 MPa (1010 psia)
Core power 128.7 kw SG secondary liquid level 1.52 m (5.0 f t)
Pressurizer liquid level 0.76 m (2.5 ft)
AFW fluid temperature 310.9 K (100 F)
HPI fluid iemperature 299.8 K (80 F)
Core flood iank fluid iemperature 299.8 K (80 F)
Core flood f ank pressure 4.24 MPa (615 psia)
T
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r TRAC-PFI te.it.si PREDICTION OF MIST TEST 310000 PRIMARY AND SECONDARY PRESSURES 14000000
-2000 Not leg / upper head I-fluid satwtated o PRIMARY
-1800 12000000-a INTACT SEC O
g f pilt over n Loop 8
+ BROKEN SEC_
S
= End of NC h
-1400 both Loops Inte>vtuption
@0
~ ~ of NC in Loop 8 BCM h Loop 8
~1200 P
SG and flow High AF BCM in Loop A SG, k
3
~
y cA>tculation in Loep 8 tart af primuty Lystem refill v
e cold legs 4
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-1000 6000000-Flow circulation SG ptimaries
-800 in loop A cold refitted legs initiated b
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2000000 0
5b0 10b0 15b0 2dOO 2500 3dOO 3500 4000 4500 5000 Tim (s) h
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Conclusions of MIST Pretest Prediction No.~
11
- Current results not significantly diff erent from previous MIST pretest co l gu l a ti ons
- MIST pretest calculation exhibits all phenomena that is expected to occur in a
B&W PWR and as observed in the OTIS tests
- Draining of pressurize'r and loop saturation
- Intermittent loop circulation
- Pool and high-auxiliary-f eed boiler-condenser heat-transf er modes
- Primary system r e fill e MIST calculation exhibits large assymetric loop behavior
- Hot leg vent valves should be opened after SG p ri ma ri es refilled to aid in f as t e r r e filli ng o f
)S,
'w the primary system and earlier compietion of the test
B&W RELAP5/ MOD 2 VERSION 3.0B ORIGIN:
RELAPS/ MOD 2 CYCLE 36.0 UPDATES:
CYCLE 36.1 ADDITIONS:
1.
HIGH ELEVATION AFW WETTING AND HEAT TRANSFER MODEL 2.
A NONCONDENSIBLE GAS HEAT TRANSFER DEGRADATION MODEL CHANGES:
1.
A DISCONTINUITY BETWEEN THE SUBC00 LED LIQUID FORCED AND NATURAL CONVECTI'ON HEAT TRANSFER COEFFICIENTS WAS REMOVED.
2.
THE VELOCITY FLIP-FLOP TIME STEP REDUCTION CONTROL WAS MODIFIED.
,o RELAP5/ MOD 2 IST ANALYSIS TASKS 1.
OTIS POST-TEST PREDICTIONS 8
FUNDED BY B&W OWNERS GROUP 2
- OTIS TEST 2202AA--A SCALED 15 CM CLPS LEAK WITH PRESSURIZER ISOLATION
- 0 TIS TEST 220899--A FEED AND BLEED C00LDOWN TEST USING PORV ACTUATION AND HPI WITH MINIMAL SG HEAT TRANSFER 8
FUNDED BY TOLEDO EDISON (DAVIS-BESSE) 2
- OTIS TEST 230299--A SCALED 10 CM CLPS LEAK WITH MINIMAL SG HEAT TRANSFER AND SCALED FULL-CAPACITY LOW-HEAD HPI FLOW.
THIS TEST INCLUDED LEAK ISOLATION, FEED AND BLEED COOLING, HIGH ELEVATION BCM, AND LOOP REFILL WIiH REC 0VERY OF SINGLE-PHASE NATURAL CIRCULATION.
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RELAP5/ MOD 2 IST ANALYSIS TASKS (CONTINUED)
II.
8 FUNDED BY MIST PROGRAM 2
- MIST TEST 310000--THE NOMINAL SCALED 10 CM CLPD LEAK USING FULL HPI CAPACITY AND INCLUDING LEAK-HPI COOLING AND POOL BCM
- M'IST TEST 320201--A SCALED 50 CM2 CLPD LEAK USING " EVALUATION MODEL" HPI CAPACITY AND INCLUDING LEAK-HPI COOLING, HIGH ELEVATION BCM, AND P0OL BCM 4 - MIST TEST 340302--A SCALED DOUBLE-ENDED 10-TUBE SGTR LOW IN THE SG USING FULL HPI CAPACITY
/h/A M]
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l KEY EVENT DESCRIPTION OF TEST #230299 8 SCALED 10 CM2 COLD LEG SUCTION LOW POINT BREAK WHICH IS ISOLATED,AFTER 30 MINUTES.
8 HPI HEAD FLOW IS SCALED TO THE DAVIS BESSE HPI-LPI
" PIGGYBACK MODE".
O MANUAL PORV ACTUATION AFTER LEAK ISOLATION TO PROVIDED FEED AND BLEED COOLING.
O MANUAL PORV ISOLATION AFTER 30 MINUTES TO BEGIN REFILL PHASE.
8 AFTER INITIALIZATION WITH HIGH-ELEVATION AFW, THE AFW IS DIVERTED TO LOW ELEVATION TO MINIMIZE THE SG HEAT REMOVAL UP TO AND INCLUDING THE FEED AND BLEED COOLING PHASE.
WHEN THE PORV IS CLOSED, THE HIGH ELEVATION AFW IS UTILIZED TO FILL THE SECONDARY LEVEL TO 12 FEET RESULTING IN A HIGH-ELEVATION BOILER-CONDENSER MODE (BCM) 0F HEAT REMOVAL.
O LOOP REFILL FOLLOWING BCM.
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4 950 120-9 FIGURE 2 OTIS Noding Diogram for Sm P 650 Test 230299
'20-6 120-10 374 370 c,p.)l
'30 I
200-8 m
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/
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p p
3 TUBE 120-5 200-7 140-1 654 150-1 16 TUBE 200-6 140-2 654 150-2 200-5 Pzr.
120-4 140-3 653 150-2 200-4 Hot 200-3 Le9 140-4 652 150-4 120-3 200-2 140-5 630-5 150-5 200-1 act
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140 6 630-4 150-6
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s-9 r-
OTIS TEST 230299-DB LOW HERD HPl HITH LERK ISOLRTION PRIMRRY RND SECONDARY SYSTEM PRESSURES 9
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TIME ISEC1 M i
CONCLUSIONS i
0 OTIS TEST #230299 INCLUDED THE FOLLOWING PHASES:
- SINGLE PHASE NATURAL CIRCULATION
- INTERMITTENT LOOP FLOWS AS THE HL U-BENDS VOID UNTIL CIRCULATION INTERRUPTS COMPLETELY
- STAGNANT LOOP LEAK-HPI COOLING
- FEED AND BLEED COOLING AFTER LEAK ISOLATION j
- HIGH-ELEVATION ECM
- LOOP REFILL 8 THE B&W VERSION OF RELAPS/ MOD 2 PROVIDED A GOOD OVERALL PREDICTION OF OTIS TEST #230299, ESPECIALLY CONSIDERING THE SENSITIVE NATURE OF THE TEST REGARDING:
- RV UPPER HEAD PHASE SEPARATION
- COLD LEG COUNTER-CURRENT LIQUID FLOW AND MIXING
- STEEP SLOPE AND SHUT-0FF HEAD OF THE LOW HEAD HPI PUMPS S
l
/84 3
i 9
MIST 340302 TEST DESCRIPTION O
SCALED 10-TUBE DOUBLE-ENDED RUPTURE AT THE BOTTOM OF SG-B e
UNCOMPENSATED LOCALIZED HEAT LOSSES MODELED 0
CORE POWER AUGMENTED TO 0FFSET UNCOMPENSATED HEAT LOSSES 8
FULL HPI CAPACITY 9
AUTOMATIC STEAM VALVE CONTROLLER IN THE AFFECTED SG TO ATTEMPT TO MAINTAIN THE LEVEL BETWEEN 10 AND 20 FEET e
NO AUXILIARY FEEDWATER TO BROKEN SG AFTER LEAK INITIATION 0
AUTOMATIC 100 F/HR C00LDOWN FOR SG-A frifi9)
cu,,,.
.uu MIST RELRPS/M002 TEST $340302 PRE-TEST PREDICTION SGTR WITH LOCRLIZED HERT LOSSES AND CORE RUGMENTRTION 9
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.CFT PRESSURE oo Oo_
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Complete loss of Nat. Circ.
SG-A Reverse f
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8 l
O 0.0 600.0 1200.0 1600.0 2400.0 3000.0 l
b*6 TIME ISEE1
'I MIST RELRP5/M002 TEST c340302 PRE-TEST PRE 0lCTION SGIR WITH LOCRLIZED HERT LOSSES AND CORE RUGNENTATION 9
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- i h
TIME (SEC1 o
ysatu, i Mist PRE-TEST CALCO LATioNS TEST NO. / M CODE STATUS 310000 35LOCA(NOMINAL)
RELAP5 COMPLETE 4
TRAC.
sENSTivlTY STunits RETRAN N PROGRESS 310505 -
SSLOCA (ASYM. SG)
TRAC.
th) PROGRESS 3Colot 6BLocA (PDMP BDMP)
TRAC NOT STAR.TED 330201 FEEMBLEED (EM ECCS)
TRAC N PROGRESS 550302 FEEIVBLEF.D (DEthY HPI)
TRAC W PROGRESS f
I Jaozol s5LOCA C50C#>
RELAP5 COMPLETE 3404o3 MTR (tG 150LATEb>
RELAP5
. DELETED 340502 saTR(LOW ELEVATION MTR)
RELAP5 COMPLETE 340100 scTra. (sG LEVEL NOMINAL)
RELAPs TBD 34o504 MTR/sts RELAps TBD