ML20206B185
| ML20206B185 | |
| Person / Time | |
|---|---|
| Issue date: | 07/26/1988 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2591, NUDOCS 8811150365 | |
| Download: ML20206B185 (49) | |
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d DATE ISSUE 0i 7/26/88 i th/W ;
Advisory Comittee on Reactor Safeguards T/H Phenorena Subcomittee Meeting Minutes ,
Status of M!$T Phase !!! & IV Programs and :
Proposed OTSG Follow-On l July 21, 1988 .
i Washington. 0.C.
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PURPOSF; The purpose of the reeting was to review the status of the M!$T Phase !!! and IV Programs and the proposed OTSG fo11cw-on Progra.n. ;
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l ATTENDEES: Principal meeting attendees included:
l ACRS NRC i t
O. Ward, Chairman R. Lee, RES !
i W. Karr, Member R. Jeres , RE', l C. Michelsen, Member L. Shotkin, RES C. Wylie, Fer.ber N. Zuber, 4CS l
!. Catton. Consultant j H. Sullivan, Consultant B&W
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i C-L. Tien, Censultant ;
9 J. G1cudet.ans '
!NEL G. Geissler l M. Parnce -
K. Coadie l B&W 0*rers Group l LANL >
P. Guill l T. Knight N. Trikorous f l
1 K. Almenas J. P. Sursock l MEETING HIGWLIGHTS. AGREEMENTS, AND REQUESTS .
l l 1. Mr. Ward noted that the ACRS had encouraged the above T/H research j i programs related to B&W reactors, as there was a need seen to bring l knowledge of E14 plant thermal-hydraulic behavior up to that of the other PWRs. A recent ACRS letter en T/H research noted that there
! should be adequate capability to predict the perforrance of S&W 8811150365 880726 PDR ACRS Q\
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1 s T/H Phenomena Meeting Minutes July 21, 1988 fiants comparable to the other PWRs. Mr. Ward said the Subcon-mittee will t y to determine if the programs are progressing and l whether there are p'oblems that need to be addressed.
Mr. Michelsen said the budget for these programs should be ex-amined with an eye to assuring sufficient funding is being provided.
Dr. Catton said RES had, early-on, cited a set of 5 concerns with ,
B&W plants. Three facilities were used to get at thase concerns and now EPR! has dropped their facility (SRI-!!). Fe asked NRC to address how closure on these issues will be obtained minus further experirental data from SRI-II,
- 2. R. Lee (RES) o',erviewed toc status of tFe MIST program. Key points roted were:
- Phase !!! testing is completed. A total of 50 Phase !!! tests were conducted. In addition, three tests were conducted for, and funded by, Toledo Edison. Phase IV testing is also completed. Eight Phase IV tests were performed.
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- Drafts of the Phase !!! reports have been issued. Final reperts will also be prepared Dr. Catton asked if the final report will address the conctrns he noted above. RES said they will be, as part of the 17 original TAG issues. RES also said that the contributions of the University of Maryland and SRI-!! facilities will also be discussed in an 'xecutive Sumrary report.
- The post-test analyses run by the Owners (with RELAP-5) and NRC (with TRAC) was discussed (Figure 2).
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D l T/H Phcnomena Meeting Minutes July 21. 1988 t
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i 1. A review of the ,results of the MIST Phase !!! test program versus [
the TAG issues was provided by J. Gloudemans {B&W). !
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Figure 3 lists the 17 original TAG issues. The "A" to "0" ratings l are the ieportance of each issue as determined by the TAG members. !
Dr. Sullivan noted that he recalls that the TAG was evaluating the I I
- need for data based ultimately en the code reeds (deficiencies). I In respense to Mr. Ward. Dr. Catton indicated that the list of f
TAG issues appears to address the cencerns he noted above. -
t j Mr. Gloudemans showed examples of how the TAG issues were addressed vis a vis 'i!ST Phase !!! tests (Figures 4-5).
An example of how a particular TAG issue was addressed in detail was also shown (Figure 6). In this case, the issue of boiler-f j condenser mcde of natural circulation core cooling (BCM) was i j discussed. B&W described the results of the various aspects of BCM f
i and also related the BCM phenorenoa to other related TAG issues. l
) Figures 7-8 show an example et how a particular BCM related issue l was addressed by the Phase !!! p*ogram. (
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l In response to Dr. Sullivan. Mr. Glouderans said there were some 1
"surprises" from the tests; i.e. some phenomena were seen that were i not expected and these incidents were instructive.
Tne conclusions shown for the BCM phenomenon were: (1) BCM was ob-l served repeatedly in a varicty of system conditions; (2) BCN was an
] effective rethod of primary-to-secondary heat transfer and primary j system depressuriaation; and (3) the BCM TAG issue has been exten-j sively addressed by MIST Phase testing.
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i l Dr. Catton noted that one must be careful in applying the M!$T teat !
I observations to full size plants via code scale-up. Messrs. Ward (
{ and Kerr indicated th t the MIST observations must be used somehow !
l _to address the issue of how well the codes can calculate transients t l of concern. Mr. Gloudemans said this issue will be discussed in [
later presentations.
4 M. Parece (B&W) discussed the MIST tett predictions using tne j RELAP 5/M002 code. A series of three separate sets of calculations .
were p rforced: one set sponsored by the FMG (Figure 9), one set t sponsored by the 81W OG (Figure 10), and 2 predictions sponsored by ;
l Toledo Edison for Davis Besse (Figure 11). Mr. Parece said that, I l in general, all tha post-test code predictions matched the test data fairly well. ;
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Dr. Catton asked how the cede will scale up to the full size plant, f l
B&W said this issue will be addressed in the future. R. Lee said I the issue will be addr,tssed by corparisen of the MIST, LHCP, and l
SR! tests via the TPAC code. Further discussion of thit point j l resulted in E&W indicating that they are benchearking the code to [
aa,tual full size plant transients. Dr. Catton said 21W still has [
to address the issue of using a or.e dirensional code (RELAP-5) on a three dirensional full-stre plant. Mr. Ward raised a concern with f
l t the fidelity of the code vis a-vis a full scale plant. Dr. Sursock I (EPRI) indicated that as long as one can bound the uncertainties l
i for the key phenomeca of inter'.st, the code will be able to model a l full size plant., M!ST was designed to bound the relevant uncertainties, i i l I
i Figures 12 and 13 show the noding used to rodel MIST with RELAP 5. j 1
I Results of two MIST tests versus post-test code predictions were !
shown. The tests were both SB LOCAs with full FPI capacity and I i
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i T/H Phenomena Meeting Minutes July 21, 1988 throttled AFW flow. The tests differed in that one used high point vents and the other depressurized one loop faster than the of her.
Points noted during the discussioni of the above results included:
- Messrs. Catton and Ward indicated that the code seems to have l either a compensating error or has been. turned to MIST; in '
that the overall mass in the RCS is calculated correctly, but the calculation of mass in the core is incorrect. Dr. Catton again noted that this problem must be addressed for scale-up
, to a full size plant. Mr. Ward said that this problem appears
- signifi". ant and reconmended that the OG should address it.
Mr. Parece indicated that tha error does not really matter, as l~ the overall result matches the dat,a. Dr. Krrr said he believe: that the code should be able to predict conditions that are not intuitively obvious. Given the current approach, i
- B&W cannot do this, as the code is tuned to the data. Mr.
1 Ward said B&W may have a problem if a' break occurs in a location not modeled in MIST, given the error shown. Mr.
r Paljug (B&W) indicated that bounding analyses would address !
this concern, i r
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- Mr. Parece concluded that RELAP-5/M002 predicts the phenomena associated with SB LOCA, SGTR and PORV/HPI cooling events on the MIST facility. Dr. Kerr questioned the conclusion. Mr. l Parece agreed that the code does do better on some phenomena than others. He said that tne predictions showed that changes to the noding are needed to assure more prototypical modeling.
Mr. Ward asked how these noding changes will help model the (
plant. Dr. Kerr again questioned the ability of the code to calculate phenomena not seen in the test facility. Mr. Parece indicated that this is usually the case with any cude. I i
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T/H Phenomena Meeting Minutes July 21, 1988 ,
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- Drs. Tien and Sullivan questioned what B&W learned that would allow scale-up of the code to full size plant. B&W said this '
scale-up is the next step and they can not, at this time, comment on direct comparisons to a plant.
- 5. T. Knight (LANL) discussed the NRC-funded TRAC post-test calcu-f lations on MIST. (Note: Dr. Sullivan has a direct conflict of i interest on thi< work.) This involved a set of pre-test (Figure
- 14) and post-test (Figure 15) calculations. The pre-test calcu- '
lations were performed with Version 12.7 of TRAC-PF1/M001. All but the first post-test calculation was performed with the frozen Version of MOD 1 (14.3). All of the post-test analyses are complete, but the reports have yet to be published.
The TRAC code model was described. It is fully one-dimensional.
Figures 16 17 show the noding used, and changes made to the code i for modeling the post-test calculations, c Selected results of the four post-test calculations were described.
Dr. Kerr asked how LANL determines what are "good" comparisons with data. Dr. Knight indicated that if key phenomena are not predicted i or the timing of main phenomena is poor, then the prediction is suspect. Conclusions ivr the SB LOCA tests are given on Figures
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- 18. For the feed and bleed test, LANL concluded that the overall ;
agreement between the calculation and the data is reasonable in i that the major phenomena are calculated. The major differences ;
seen occurred in the quantitative comparisons: 1.e., primary pressurization rate, PORY mass flow, and timing of the secondary
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system dryout. The 50 tube rupture test modeling showed: (1) [
, TRAC-PF1/ MODI calculated the major phenomena occurring during the I transient; (2) major events were delayed in the calculation because I t
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. c. l, T/H Phenomena Meeting Minutes July 21, 1988 of lower calculated SGTR flow; (3) input model changes could improve the SGTR flow; and (4) the data are insufficient to ade-quately assess the TRAC critical-flow model. In response to Mr.
Michelson, Dr. Knight said that TRAC can model all the major T/H phenomena seen during the SGTR including the ruptured SG becoming a heat source. Regarding the critical flow model, Dr. T1en said the data shows that the model can be evaluated for its accuracy given the transient of interest.
- 6. The test observations of the University of Maryland (UMCP) facility were discussed, as they pertain to the issues of geometric atypica-lities for MIST (and UMCP). Four atypicalities were considered:
(1) downcomer, (2) reactor vessel vent valves (RVVV's), (3) pipe size; and (4) storeo heat. Figures 18A-20 detall the UMCP facility design.
University of Maryland evaluated the atypicalities from two ap-proaches: (1) empirical, i.e. provide assurance +. hat safe opera-tion is maintained; and (2) phenomenological, i.e. provide ability to model the major phenomena. Dr. Almenas said that the atypicali-ties do not significantly effect the Item (1) concern above, but they do influence a number of modeling aspects. Dr. Almenas said there have been no unexpected results regarding either core un- ,
covery or the ability to remove heat from the RPS (i.e. the core has remained covered and adequately cooled for all tests). In response to questions from Dr. Kerr, Dr. Almenas indicated that he believes the UNCP test results are applicable to full scale plant behavior as the T/H phenomena seen are generic in nature (for B&W plants).
Dr. Tien questioned that any phenomena observed in a scaled facility can be considered applicable to a full-size plant-absent a thorough scaling study.
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T/H Phenomena Meeting Minutes July 21, 1988 ;
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. Test results were discussed to illustrate the bases for the state- !
ments made above. One of the unexpected results of the tests was
, that the loop-to-loop oscillations seen were caused by condensation "pull" resulting from collapse of vapor in the vessel upper plenum. :
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Dr. Michelson suggested that the codes should be applied to the case of loop-to-loop oscillatory flow to raise one's confidence in their predictive capability.
Conclusions of Dr. Almenas presentation are given on Figures 21-22.
- 7. J. P. Sursock (EPRI) discussed the SRI-2 experiment results and the SAIC experiments on AFW spreading and counter-current flooding in the OTSG's. For the SRI-2 tests, the facility was described (Figure 23), and the test matrix was reviewed (Figure 24). Because of funding constraints and technical problems encountered with the facility, the above test matrix represents a truncation of the originally planned test series.
Key conclusions of the SRI-2 program include:
- For single phase natural circulation:
- Loop flow oscillations are sensitive to AFW system operation;
' For two-phase natural circulation:
- Three cooling modes exist; they are inventory-dependent:
- A very large peak flow mode at about 75% inventory
- Loop-flow interruption at about 60% inventory
- Boiler-condenser mode at about 56% inventory;
- Vent valves opened only at low inventory and did not stay open for long periods of time;
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July.'21,'1988 J
remove the core power. The steam generators 5ere not per.ded ;
as heat sinks; y
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- The SRI-II test data can provide a fertile source for coniputer ,
I code validation. L f
Addressing the scale-up issue, Dr. Sursock indicated that as long l as the codes demonstrate accuracy within accepted uncertainty ,
bounds, that is acceptable. Cr. Sursock agreed with Dr. Catton that a given frozen code should be able to acceptably predict test results from the above three facilities. Dr. Tien said he is skeptical that one can do the above task absent a comprehensive scaling analysis. Dr. Sursock noted that all three test facilities J are reproducing the same key T/H phenomena, even with different i pressures, configurations, etc. He said no big surprises have been seen in any of these facilities.
The SAIC tests characterizing the AFW flow distribution (tube l wetting) were overviewed by Dr. Surseck. Figure 25 shows a sche- l matic of the AFW test facility. A flooding map was developed, (
based on the test results (Figures 26). ;
t Key conclusions of the above work were'
- Distinct flow regimes at the tube support plane (TSP) were [
observed; either flooding, or no flooding; I
i flooding was observed. The height of the pool depended on the !
AFW and injected steam flow rates; !
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- Flooding was caused mainly by boiling of the AFW at the TSP, even for.the cases where there was no steam injection. !
Conditions at the TSP were at saturation, and the primary-to-secondary heat transfer supplied the phase change energy.
This implies air-water tests of this phenomenon will not l
provide useful information. ;
- 8. Tne status of the MIST test observations referred to the B&WOG for
, follow-ur-piven the potential for observations to impact plant operations was discussed by Guill (B&WOG).
] The IST observation program was described (Figure 27). Dr. Catton asked if this program is evaluating the SRI-2 or UMCP test data. !
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.Mr. Guill said they are not using this data. Dr. Catton urged them
- to do so in order to address the issue of atypicalities noted i l
above. Dr. Kerr asked if a "black-hat" group is evaluating these -
observations to assure objectivity of the B&WOG evaluations. Mr. !
i Guill indicated this was not the case. Mr. Ward asked if the B&W '
- SPIP (safety performance improvement program) is related to this
! effort. Mr. Guill indicated that SPIP is separate from this program. In response to Dr. Sullivan, Mr. Paljug indicated that the observation program is designed to examine the impact of the ,
observations on plant operations. The adequacy of the code f
vis-a-vis these observations will be addressed in anotter parallel ;
j program. However, the parallel program will not examine at SRI or j j UMCP data, i
j The status of the observation program were shown (Figure 28). Of ,
j 95 observations, 15 are being evaluated for impact on plant opera- ,
l tions, 2 potentially impact code development, and 4 impact an) ,
j future MIST testing. No need for any innediate action has been j found from the observations evaluated to date.
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T/H Phenomena Meeting Minutes July 21, 1988 i
- 9. N. Trikou,rous (B&WOG) discussed the status of the TAG effc.-t to [
investigate the experimental T/H data need(s) associated with OTSG. i The scope of the effort was limited to the OTSG and to B&W !
plant-specific issues only. A flow chart of the TAG process was l discussed (Figure 29).
A list of T/H phenomena believed to occur in OTSs , was evaluated l for importance. The selection process used was designed to focus !
attention.on the phenomena considered of highest importance. ;
Figures 30-31 detail the process. Mr. Trikourous said the TAG j plans to evaluate the items deleted from the list as not applicable ,
to B&W plants, to assure no generic issue (s) is being missed.
- The selection process is nearly complete, as are the sensitivity l studies or the key phenomena. A formal report on the TAG effort is being prepared and should be complete in late August. '
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, Dr. Sullivan comented on the TAG process. He indicated that the l
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i process is keyed to identify data for use in the code. Instead, he 3
believes one should be evaluating a code to see what deficiencies ;
i exist or what is needed to develop a new code, given the proper test data. B&W indicated that they felt it was feasible to evalu- i
! ate the phenomena in the OTSG, but they couldn't invision all the
! uses/needs for the code. Dr. Sullivan said the TAG should develop i
! a list of phenomena of interest and then determine how this !
l phenomena will be benchmarked to the code needs. Mr. Trikourous L .
indicated that he believes that as long as the TAG gets to the same l
place, i.e. the code is fixed, its OK. In response to Mr. Ward, !
Dr. Sullivan said he is concerned that the above process will lead to failure to fix the code deficiencies. ;
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T/H Phenomena Meeting Minutes July 21, 1988 Mr. Ward indicated he didn't see that the.SG code models are that bad. Dr. Sullivan noted that there-is alot of separate effect l U-tube SG data available that is lacking for the OTSG. He said that the TRAC SG model is not considered by LANL to be very good.
I Concentrating on the code model deficiencies will assure the real concerns are addressed.
l L Dr. Catton said the top-down approach advocated by Dr. Sullivan is j more likely to succeed where the TAG approach looks like a bottom-up approach which is difficult at best. Dr. Wolf (INEL) said there is a task underway to look at the fidelity of the OTSG steam generator model in the RELAP-5 code and upgrade it as necessary.
Condie. The objective of the program was to obtain T/H experi-mental data pertaining to auxiliary feed-water injection in a B&W coce-through steam generator for improvement of the code models.
Single- and multi-tube tests were run at INEL (Figures 32-33). The conclusions noted from the tests include:
- Flooding data obtained is t'milar to other multi-hole test data;
- Minimal. radial penetration seen below top tube support plate the until the flooding line is approached;
- Models nave been developed and are being in.plemented into REldP-5,
- 11. T. Knight (LANL) discussed the status of the sensitivity studies for the OTSG TAG effort noted above. The program is investigating the significance of uncertainty in models and code nodilization as they pertain to calculated OTSG performance and the resulting
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T/H Phenomena Meeting Minutes July 21, 1988 impact on primary system behavior. The selection rationale for the parameters considered include: (1) brief duratior, phenomena generally result in less impact on the transient (although counter examplesdoexist);(2)long-termphenomenapreimportant;(3) expected uncertainty in a parameter may % duce significant changes in the course of the transient; and (4) some parametric effects can be combined. Figures 34-35 shows the division of labor between INEL and LANL on this program.
Currently, mapping and overfill-transient calculations are complete. The steam line break transient analyses are almost complete.
The preliminary AFW wetting resu.lts (NC mapping) shows that the RCS mass flow is not very sensitive to the wettinr fraction of the SG tubes vis-a-vis AFW injection. Further analysis of all the cases is still underway. (Note: H. Sullivan was in conflict for this presentation.)
- 12. Prior to adjournment, Mr. Wylie (Acting Chairman) requested a written report from the Consultants, emphasizing any follow-on items for discussions at future meetings.
- 13. The meeting was adjourned at 6:10 p.m.
I NOTE: Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, 4
1717 H Street, N.W., Washington, D.C., or can be purchased from Heritage Reporting Corporation,1220 L Street, N.W.,
- Suite 600, Washington, D.C. 20005 (202) 628-4888.
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Phase-Ill tests: [
l Mapping - 9 .
Boundary system - 11 -
Leak-HPI configuration - 6 Feed and bleed - 4 ;
Steam generator tube rupture - 7 l I
Non-condensible and venting - 6 l Reactor coolant pump operation - 6 l
- Other - 1 a
l Phase-IV tests: l
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- i SBLOCA w/o HPl - 2 [
l MIST scaling - 3 l
- Station blackout - 1 l l Intermediate size break - 1 j Steam generator steady state - 1 !
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EST Sca;us -continued.-
Post-test analyses:
RELAPS analyses completed.
Draf t report issued.
320302: Cold leg suction break 320303: CLD break w/- leak isolation 340213: 1 SGTR, one loop cooldown 3502CC: Non-condensible gas 3801 AA: Core uncover TRAC onalyses completed. Dra f t reports in preparation.
3109 AA: CLD (10 sq. cm) 320201: CLD (50 sq. cm) 3404AA: 10 SGTR, isolated SG .
330302: Feed & bleed, delayed HPl
TAG Evaluation of Issues TAG issues from the TAG final report.
Natural Circulation Single phase natural circulation 0 Two phase naturcl circulation C Boiler condenser natural circulation A Steam generator driven instabilities B Cold leg oscillations B Interruption / reestablishment B High point vents A/D Non condensible gases B Reactor vessel vent valves C S all 9reak loss of Coolant Accident Break size C Emergency core cooling system operation C oeactor coolant pump operation B Location of break 0 Break isolation B R'e actor vessel vent valves B Feed and Bleed 0
- Steam Generator Tube ouoture 8
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EXCERPT FROM HIST FINAL REPORT VOLUME 1 (
SUMMARY
)
APPENDIX A, "MIST VERSUS THE TAG ISSUES: DETAILS" Table A 1. Selected Tests Illustratina Natural Circulation Conditions Test Volume Nominal, stable 3109 Nominal SBLOCA 3 Reduced hydraulic resistance 3600 Repeat Nominal SBLOCA with 8 Pump Configuration Maximum wetting 3111 SBLOCA: Maximum AFW 3 Wetting Elevated steam generator level 3004 Mapping: No HPl. Leak 2 Cooling Post refill 3109 Nominal SBLOCA 3 Two. loop cooldown 3201 SBLOCA: Reduced Leak Size 4 Single loop cooldown 3402 Single Tube Rupture 6
- 3407 Single Tube Rupture with 6 Pressurizer Venting I
Characterization ....
Characterization of RVVVs Char'n.
l and Downcomer e
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F/I +
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1 Etaglution Of the TAG issutI .
Entries indicate selected tests applicable to the corresponding 1AG Issue.
14 15 16 Il 3 4 5 6 7 8 9 10 11 12__ 13 Is1 G er- 1 2 Test I I GInut_M - Menins .
I 1300001: Test 0, lacreased teak Stre cm2 I 1300198: Test 1. Pressertzer Isglated I I I I I
13003AA: Test 3. Noelmal cm' I I I
I 13004CC: lest 4. HPI Inactive '
1300504: Test 5. RVVVs Closed 1300605: Test 6. Unequal Steam Generator tevels 13007CC: 1est 7. tomered Steam Generator twels I 1300006: lest 8. Pumps Operating I 13009AA: Test 9. Cold leg Dischange teak Ginvej l - SSLDCA: Yetit4_S94Rd4IIl9edill961 I
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131:101: Test 1. RVVVs Closed 1310201: Test 2. RVVVs Open 1310302: Test 3. Guard Heaters Deenergized I I
1310403: Test 4. Sand Steam Cenerater tevel Control I I 13105AA: Test 5. throttled Afif and Asyumetric Cooldoun I I 1310699: Test 6. ATOG I 1312702: Test 7. No Augmentatles of Core Feuer I I I I I I I I I I I 13109AA: Test 3. Nominal I I I I I I 1311000: lest 10. Nominal Repeat I
131tlAA: lest II. Masteen feed Wetting I Group 32 - 5810CA: Altered leak and HPI (9Bi19Etlllens 2 I I I I g g 1320101: Test 1. Reduced teak Stre cm 2 1320201:. Test 2. Increased teak Stre cm I '
I 1320302: Test 3. Cold leg Sectica teak I 13294AA: lest 4. FORV Break I .
I 1320943: Test 5 teak Isolated I I 1320604: lest 6. Reduced-Capacity NPI I
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' Green 33 - Irl-PORY Coellag 1330188: Test I. Nominal 1330201: Test 2. Reduced-Capacity HPI 1330302: lest 3. Delayed HPI 1330499: Test 4. Serge Line Uncovery
^ MI N 4
BOILER-CONDENSER MODE (BCM) 0 ISSUE: BOILER-CONDENSER NATURAL CIRCULATION (BCM HEAT TRANSFER AND PRIMARY SYSTEM DEPRESSURIZATION) .
O "BCM" IS THE CONDENSATION OF PRIMARY SYSTEM VAPOR WITHIN A. STEAM GENERATOR .
O SIGNIFICANCE:
1 EVALUATED "A" BY THE TAG i
METHOD OF PRIMARY-T0-SECONDARY HEAT TRANSFER WITH A VOIDED PRIMARY SYSTEM t
j 0
SUMMARY
- BCMs OBSERVED EXTENSIVELY, WITH A WIDE RANGE OF CONDITIONS i
BCM WAS AN EFFECTIVE METHOD OF PRIMARY-TO-l SECONDARY HEAT TRANSFER AND PRIMARY SYSTEM DEPRESSURIZATION l . . _ _ _ . _ _ _ . . _ _ _ _ _ _
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SINGLE-LOOP AND TWO-LOOP BCMs 0 NOMINAL SMALL BREAK LOCA TEST 3109 SCALED 10-CH2 (0.011 FT )2COLD LEG DISCHARGE BREAK FULL-CAPACITY HIGH-PRESSURE INJECTION (HPI)
AND STEAM GENERATOR FEED -(AFW)
NATURAL CIRCULATION 0 SINGLE-LOOP BCM DURING INITIAL INTERRUPTION SEQUENCE CAUSED BY INTER-LOOP ASYMMETRIES 0 TWO-LOOP BCH CAUSED BY DEPRESSURIZATION OF STEAM GENERATOR SECONDARIES OBTAINED DEPRESSURIZATION OF THE PRIMARY SYSTEM AND THE START OF REFILL
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0 RELATED TAG ISSUES INTERRUPTION /RE-ESTABLISHMENT (0F NATURAL CIRCULATION)
BREAK SIZE (EFFECTS ON SMALL BREAK LOCA)
I 0 RELATED OBSEi/!ATIONS AND OPEN ITEMS l INITIAL INTERRUPTION
- HOT LEG LEVEL DIFFERENCES, ASYMMETRIES BCM HPI OVERC00 LING EXTENDED COUPLING 0
SUMMARY
(AFW) BCMs OBSERVED REPEATEDLY
- OBTAINED PRIMARY-TO-SECONOM Y HEAT TRANSFER, PRIMARY SYSTEM DEPRESSURIZATION, START OF REFILL l -
REFILL ULTIMATELY CAUSED INTERMEDIATE HOT LEG LEVELS (AB0VE THE STEAM GENERATORS,
! BELOW THE HOT LEG U-BEND SPILLOVER
- ELEVATION), TERMINATING BCM,
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MIST TEST PREDICTIONS WITH RELAP5/ MOD 2 1 MIST PMG SPONSORED PREDICTIONS
! TEST PREDICTION i NO DESCRIPTION MODE 3109AA HOMINAL TEST. 10 cM CLPD BREAK PRE-TEST
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- 3406AA 10 TUBE RUPTURE AT LOWER SG TUBE PRE-TEST ~
SUPPORT PLATE WITH FULL HPI 132b503 10 cM CLPD BREAK WITH FULL HPI P63T-TEST AND AFW. BREAK ISOLATION AT 30 MIN.
320302 10 cM CLPS BREAK WITH FULL HPI & AFW POST-TEST I4
- 320213 SCALED ONE TUBE HIGH ELEVATION SGTR POST-TEST 3502CC NONCONDENSIBLE GAS THRESHHOLD TEST POST-TEST 3801AA CORE UNC0VERY WITH RC PUMPS RUNNING POST-TEST
$m.
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MIST TEST PREDICTIONS WITH RELAP5/ MOD 2 BWOG SPONSORED PREDICTIONS TEST PREDICTION NO DESCRIPTION MODE
~
320201 50 cm CLPD BREAK. POST-TEST 320604 10 cs CLPD BREAK W/ EM HPI POST-TEST 3105AA 10 cm CLPD BREAK W/ THROTTLED AFW POST-TEST AND ASYMMETRIC S6 C00LD0WN RATES. -
350101 10 cM CLPD BREAK W/ HIGH POINT VENTS POST-TEST -
3601AA 10 cM CLPD BREAK W/ RC PUMP BUMP POST-TEST 3404AA 10 TUBE HIGH ELEVATION SGTR POST-TEST
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MIST TEST PREDICTIONS WITH RELAP5/ MOD 2 TOLEDO EDIS0N SPONSORED PREDICTIONS TEST PREDICTION N_0 IlESCRIPTI_0_N MODE 370199 NATURAL CIRCULATION C00LDOWN PRE-TEST :
WITH CONTINU0US RV HEAD VENT 330499 PORV/HPI COOLING WITH POST-TEST SURGE LINE UNC0VERY d
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told tes BI Cold teg 32 steam Generatee 8 m w w- yr-
Pretest Calculations The pretest calculations were presented here on June 18,1987.
310000 -- MIST nominal SBLOCA, scaled 10-cm2 break with nominal HPl and AFW, symmetric SG cooldown (corresponds to test 3109AA).
310503 -- same as 310000 except for throttled AFW and asymmetric SG cooldown.
320604 -- same as 310000 except used evaluation model (EM) HPl capacity.
330201 -- feed-and-bleed cooling with EM HPl -
head flow characteristics.
330302 -- feed-and-bleed cooling with fu!! HPl delayed 20 minutes after first lifting of PORV.
We used TRAC-PF1/ MOD 1 (version 12.7) for all final pretest calculations.
7/21166 4 AtlST Pos'. est Calculations: ACRS
l .
Posttest Calculations 3109AA -- MIST nominal SBLOCA (TR AC-PF1/ MOD 1, version 12.7) 320201 --like 3109AA with scaled 50-cm2 break (TRAC-PF1/ MOD 1, version 14.3) 330302 -- feed ".ad bleed cooling with full HPl delayed 20 minutes after first lifting of PORV (TR AC-PF1/ MOD 1, version 14.3) 3404AA -- SG tube rupture representing scaled 10-tube rupture (TR AC-PF1/ MOD 1, version 14.3)
AtIST Postlest Csiculsflons: ACRS 7/21188 5
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Model Changes for the Posttest Calculations Converted to single channel secondaries.
t increased the pump heat losses by ~1s25 kW per pump at 500oF. ,
Modeled measured AFW flow during the transition to constant level control at the end of the SG refill.
Used break-flow multipliers of 0.87 and 0.87 for the 10-cm2 leak;1.0 and 0.87 for the 50-cm2 leak.
Removed heat losses for the cooled l thermocouples in the pump suctions (~1.1 kW
- each). .
l Modeled a 1.5 kW heat loss from each SG steam l
i line.
f Used measure.d test data with the TRAC l pressurizer heat / sprayer option to model MIST
! pressurizer heaters.
i 1
l i
7/21188 10 MISTPostlest Csiculations: ACR$
,l
3109'AA and 320201 Conclusions l
TRAC-PF1/ MOD 1 calculated a variety of SBLOCA phenomena with reasonable agreement to the l data. l The calculated results for the MIST facility are very sensitive to the boundary conditions l
Imposed. l The SG secondary boundary flows and pressure response must be modeled correctly to predict the l BCM phenomena.
Accurate steam line heat loss modeling is important for a wide range of SBLOCA leak sizes.
Factors affecting the timing of AFW BCM also affect the magnitude of the BCM.
Differences between calculations and experiments resulted from underpredicting the niagnitude of AFW BCM heat transfer.
7/21188 20 _.
MISTPosttest Csiculations: ACs:3
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ic Conclusions - Phenomenological
- RVVV -
Key local mechanism causing loopwise IRM oscillations
- Pipe Size -
Effect on stratified cold leg flow and condensation shocks.
- Annular Downcomer - ,
Inertial resistance reduces communi-cation between cold legs. Dampens ;
higher frequency phenomena.
- Stored Heat -
Indirect evidence of smallimpact.
zo I
Conclusions - Empirical Base line !
The four considered Atypicalities l
- Do not influence core uncovery i l
- Do not significantly affect core to i steam generator enthalpy l transport i
- Modify but do not qualitatively !
I change the basic characteristics of !
! a SB-LOCA transient
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l Fi gure 3 20. $RI.2 1.000 Instry entation 3-57 w-
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.1 '.
SINGLE-PHASE NATURAL CIRCULATION TEST
- MAY 28, 1987
- AUGUST 4, 1987 TWO-PHASE NATURAL CIRCULATION TEST
- JUNE 4, 1987
- JUNE 11, 1987 SEPTEMBER 3. 1987 SMALL-BREAX LOCA
- JUNE 25, 1987 COUNTERPART MAPPING TEST
- AUGUST 13, 1987
- SEPTEMBER 3, 19S7
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- i?ure 13. loc:1ng Mac a :.ae 7t:
- fid Ob -
- o .
IST OBSERVATION i.0.^^R AM IST PROGRAM o
TEST DATA EVALUATION TEST
- /ERFORMANCE ID OF OBSERVATIONS o FILTER IST REPORTS f ENGR EVALUATION F
o PLANT CODE MIST o
BWOG COMMITTEE EVALUATION II ANALYSIS o
ATOG/ PLANT CODE PROC EDUR ES/ MODS UPGRADE TRAINING CHANGES -
I . _
NO ADDITIONAL ACTION REQUIRED ~
FOR RESOLUTION o
FINAL REPORT :
NOTE: PSC PROCESS IS SEPARATE AND INHERENT; AND CAN BE ISSUED AT ANY TIME IF WARRANTED ,% -- %
Ifx a ,
- 6' *
- '
- :. . a l
STATUS l d
o DOCUMENTED 95 OBSERVATIONS o IMNTIFIED 21 OBSERVATIONS FOR INITIAL BWOG COMMITTEE EVALUAT10ti l
0 THE 2] INITIAL OBSERVATIONS FALL liiTO THE FOLLOWING CATEGORIES !
L PLANT 15 j g
CODE 2 I 1'
! MIST 4 :
. I 4
ID OF OBSERVAT10flS 95
(
i l . t o -
4 ENGINEERING EVALUATI0tt [
74 I
Pl.AtiT CODE MIST
, 15 2 4 J.
f 1 BWOG COMMITTEE EVALUATION {
21 ,
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l !
Im1 n) >
-- = -. . - _ __-
.; o TAG PROCESS DIAGRAM COMPREHENSIVE PLANT /OTSG APPLICATIONS CONDITIONS (TRANSIENTS)
=
BREAKDOWN
- > INTO I PHENOMENA v
NO DOCUMENT SELECTION l > IN CRITE RIA l Rp YES N v
REDUCED PHENOMENA .
LIST
+
h k AVAILABLE SENSITMTY DATA STUDIES BASE
- NO NEED FOR ADDITIONAL DATA >
f'6S .
DETERMINE METHOD TO OBTAIN DATA REPORT l Gean
~
SELECTION PROCESS PROCESS THAT ALLOWS US TO FOCUS OUR ATTENTION ON THE HIGHEST PRIORITY PHENOMENA STEP 1 USING COLLECTIVE ENGINEERING EXPERIENCE DETERMINE THAT:
A. THERE IS NO IMPACT ON OTSG PERFORMANCE, OR B. THERE IS SUFFICIENT DATA BASE STEP 2* IS THE PHENOMENON SPECIFIC TO THE OTSG GE0 METRY, OR IS IT A MAJOR FACTOR IN OTSG BEHAVIOR RELATIVE TO OTHER SG DESIGNS ITEMS REDUCED BASED ON THIS CRITERION WILL ALSO BE EVALUATED FOR DATA BASE ADEQUACY AND A MORE DETAILED REVIEW 0F THEIR EFFECT ON PRIMARY SYSTEM BEHAVIOR lisiD
SELECTION PROCESS (CONT'D)
STEP 3 PERFORM A MORE DETAILED REVIEW 0F AVAILABLE DATA BASE, THEN PRIORITIZE REMAINING PHENOMENA ON THE BASIS OF DATA BASE INADEQUACY AND IMPORTANCE TO OTSG BEHAVIOR SIEP 4 PERFORM SENSITIVITY STUDIES ON HIGHER PRIORITY PHENOMENA TO BETTER DEFINE IMPACT ON PRIMARY SYSTEM BEHAVIOR.
REPRIORITIZE ON BASIS OF SENSITIVITY STUDIES STEP 5 CONSIDER REMAINING HIGH PRIORITY ITEMS FOR DEFINITION OF PRIMARY TEST FACILITY CONCEPT AND DATA REQUIREMENTS I
. . %x Ol
D% From demineralized *
"e
- water storage tank Feedwater
" Air bypass h g His g To drain Simulated steam generator tubeQ X 3 (x i
- Air suction g h/ ,
y Air water fan h '
separator 5A E \/
At I tA
/ (
suppo b CP Tube Tube support P!;te s plate s exan m
N Level Lexan control shroud tube g Collector
\
)
l
+m Weigh Catch
- -p Weigh tank tank tank ,
Single Tube Adiabatic Air Water OTSG Test Fixture
$ e G
- ~s .
Multitube Adiabatic Air Water OTSG Test Fixture Y
Upper tube / Air water sheet / exit y
q'- ) pr .
W k Auxiliary fN g feedwater inlet
(
ey)g ruee
/. Approximately 625 stainless i
i/p ;
tubes 1/8 sector
)>
f/ \ [Variabie bypass area (3) p Tube support j i plate (3)
Lexan
( , shroud N
Air inlet
] d 7 1425
-- A -
r
.e.
Program Plan Natural circulation mapping: INEL; vary magnitude of wetted region and secondary level.
BCM mapping: Los Alamos; vary magnitude of wetted region and primary level for AFW BCM.
Overfill transient: both; vary interfacial heat transfer on secondary and wetting fraction.
Steam-line break: both; vary interfacial drag on secondary and break area.
I i
I l
l 1
l l
l OTSG Sensitivity Studies: ACRS 7/21/88 5
! .D*
- 1 Computer Codes
- INEL: RELAP5/ MOD 2 with an update to force the wetting on the secondary from the normal l heat-transfer package; additional updates l l to permit varying the interfacial drag and ,
heat transfer. l l
Los Alamos: TRAC-PF1/ MOD 2 with the same type of updates required for INEL.
Both labs will do a subset of corresponding calculations to investigate code behavior.
OTSO Sensitivity Studles: ACRS 7/21186 6 -
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