ML19269F022
| ML19269F022 | |
| Person / Time | |
|---|---|
| Issue date: | 07/31/1978 |
| From: | Basdekas D, Curtis R, Silberberg M NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | |
| References | |
| NUREG-0457, NUREG-457, NUDOCS 7911140460 | |
| Download: ML19269F022 (50) | |
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NUREG-0457 Revision 0 A O.UALIFICATION TESTING PROGRAM PLAN FOR SIMMER A COMPUTER CODE FOR LMFBR DISRUPTED CORE ANALYSIS July 1978 2189 258 Office of Nuclear Regulatory Research U. S. Nuclear Regulatory Commission
- 7911140ffO
f Available from National Technical Infonnation Service Springfield, Virginia 22161 Price: Printed Copy $5.25 ; Microfiche $3.00 The price of this document for requesters outside of the North American Continent can be obtained from the National Technical Information Service.
2189 25'i
NUREG-0457 Revision 0 R7 A QUALIFICATION TESTING PROGRAM PLAN FOR SIMMER A COMPUTER CODE FOR LMFBR DISRUPTED CORE ANALYSIS 2189 260 By Demetrios L. Basdekas Mel Silberberg Robert T. Curtis Charles N. Kelber Office of Advanced Reactor Safety Research Division of Reactor Safety Research Office of Nuclear Regulatory Research U. S. Nuclear Regulatory Commissic, Washington, D. C. 20555
TABLE OF CONTENTS PAGE LIST OF FIGURES....................................................
11 LIST OF TABLES.....................................................
iii I.
INTRODUCTION.............................................
1 II.
EXECUTIVE
SUMMARY
4 III.
0BJECTIVES...............................................
7 IV.
A BRIEF DESCRIPTION OF THE SIMMER C0DE...................
8 V.
RELATIONSlIP 0F THE QUALIFICATION TESTING PROGRAM PLAN TO SIMMER DEVELOPMENT....................................
12 VI.
DEVELOPMENTAL QUALIFICATION TESTING PLAN.................
16 VII.
INDEPENDENT QUALIFICATION TESTING PLAN...................
22 VIII.
QUALIFICATION ACCEPTANCE CRITERIA........................
26 IX.
SCHEDULES - REP 0RTING....................................
27 X.
REFERENCES...............................................
El APPENDIX A -- ONG0ING EXPERIMENTS..................................
30 APPENDIX B -- NEW EXPERIMENTS......................................
31
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2189 261 i
LIST OF FIGURES PAGE Figure 1.
Basic Plan for SIMMER Qualification Testing...............
32 Figure 2.
Illustration of Step-by-Step Parallel Progression in Analytical and Experimental Efforts Leading to Model Qualification Tes ting and Parameter Estimation............
33 Figure 3.
Illustration of Step-by-Step Parallel Progression in Experiments and Analysis Intended to Provide Understanding of UO2 Fragmentation and Vapor Bubble Dynamics under Sodium-(CRI-III and FAST Facilities at 0RNL)..................................................
34 Figure 4.
Basic Plan for Independent SIMMER Qualification Testing...
35 Figure 5.
SIMMER Qualification Testing Planning Sc'edule for the Near Term.................................................
36 2189 262 i :e.
081%
ii
LIST OF TABLES PAGE Table I Major Areas Requiring Qualification Testing for the Vessel Problem........................................................
37 Table II Experiment Matrix for SIMMER Qualification Testing to be Add res sed on-Goi ng Prog rams....................................
38 Table III Experiment Matrix for SIMMER Qualification Testing to be Addressed by New Programs......................................
39 Table IV Experiment Matrix for Separate Technical Issues Related to Assumptions in the Development of SIMMER (New Programs)........
41 Table V Facili ty Functional Capabili ties...............................
42 Table VI Experiment and Facili ty Needs Sumary..........................
43 2189 263 iii
QUALIFICATION TESTING PROGRAM PLAN FOR THE SIMMER CODE I.
INTRODUCTION SIMMER verification was discussed in an interim report issued internally on September 14, 1977.I The first Research Review Group meeting on this task was held on March 21-22, 1978.2 One of the first items to be reviewed was the word verification itself. The question was whether or not verification, or development, or some other term would be more appropriate to describe the task at hand. Good arguments can be made that one word is better suited here than another. After careful consideration of the arguments and sLggestions we heard, we decided to adopt the term Qualificat?.on Testing to denote this task.
The SIMMER Code, developed et Los Alamos Scientific Laboratory, analyzes the various phases of a CDA in an LMFBR. The qualification testing program, as discussed in Se<.tions V - VII comprises two stages. The first stage is developmenta4 qualification testing, which involves interaction with code deve'opment itself. The second stage is independent qualification :esting and it involves an independent audit of the first stage and conf'rmatory predictions of large experiments without a priori adjustments of the Code. The developmental qualifi-cation testing is partially in parallel with code development and is dictated by constraints of time and resources. SIMMER's timely availability and utility for licensing purposes will mepend on the success of a systematic qual.ification testing program.
The ARSR program will be focused on the following three accident sequences for at least the next several years:
a.
Whole-core post disassembly work-energy partition (vessel problem),
b.
The single' subassembly disruption, and, c.
Whole-core transition phase (meltdown and recriticality problem).
2189 264
- ni o
The basic approach and near term plans for SIMMER qualification testing are based on curri1t understanding of these experimental needs and their potential to serve the most important concerns in CDA analysis.
This ARSR task is intended to identify specific technical aspects of CDA analysis requiring qualification testing and model development, the type and scope of experiments required for that purpose, and the needed instru.1ents, which may require dedicated R&D effort.
This plan is not intended to present the detailed definition and struc-ture of each experiment proposed in a manner comparable to on-going or authorized experiments. That will be done as part of on-going contractor efforts. Specific proposals are expected later this fiscal year.
Following a discussion of the background and basic concerns in CDA analysis, this plan presents a statement of its o'..iective, a descrip-tion of the approach and scope of the experimcr.L, program, along with a summary of the experimental needs and a near term planning
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schedule.
It represents the initial attempt to consolidate ARSR efforts to manage the SIMMER qualification testing program.
This document will be revised periodically as the needs and resources become better known.
It should be pointed out that the qualification testing program for a large and complex computer code such as SIMMER is multifaceted:
identification of experimental needs; design of experiments; develop-ment of instruments needed for specific physical regimes and para-meters; continuing model development, etc. These facets have to be planned and coordinated for an optimum achievement of objectives intended to serve the user needs. Since this has to be done within a restrictive framework of available resources, this task is difficult.
The vessel problem receives relatively higher priority now because its devel opme.3 ; 'ntslnofismoreadvanced.
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age 2189 265
. This emphasis, however, does not imply that the other areas of concern in CDA analysis, notably the transition phase and transition to the transition phase will be neglected. They still require considerable work in development, however, and therefore, their qualification testing efforts will have to trail those for the vessel problem.
Even though all experimental naeds are not precisely known, nor could they now be intelligently established in an all-inclusive sense, we feel that we should proceed on the basis of what we ur.ierstand to be the most important aspects of CDA analysis that need qualification testing. These aspects include basic assumptions about the accident scenario, boundary conditions, initial conditions, modeling of the basic physical and/or chemical processes, as well as important physical parameters needed for input to the code.
Aspects related to the neutronic processes are addressed separately and are not part of this program.
We expect this plan to be an evolving prospectus of the experimental program needed for the qualification testing of SIMMER. As this evolutionary process toku place, the code input needs will be more precisely defined. This in turn may reflect back on the experimental program. This process is shown in Figure 1.
This early draft of a qualification testing program plan is the result of an attempt to put the task and approach of SIMMER qualification testing to early and continuing scrutiny by the technical community.2 This plan does not have, at this time, all the elements it should have to satisfy exacting and ideal technical requirements. We are in the process, through our contractors, of developing the details of the design of experiments, instrument needs, and, painfully, the attendant financial planning. Continuing work and review are needed to complete this job; and, when it is done, the plan will have been carried out, m v8is
.2189 266 II.
EXECUTIVE SUitMARY This is a plan for a long-term program to establish the basis for the use of SIMMEtt to make key licensing decisions.
The objective of SIMMER qualification testing in general is to assure that the mathematical models and input parameters are derived from experimental data which, on the basis of criteria still to be established, are representative of the phenomena and processes governing th'e progression of a CDA in an LMFBR. At-the present time, the work to meet these objectives can be classified into three general task areas as they relate to the use of SIMMER in CDA analysis.
These task areas are:
a.
The whole-core energetic disassembly accident, or the " vessel problem,"
b.
The single subassembly accident and its propagation potential to adjacent subassemblies, and c.
The whole-core transition phase to meltdown and its potential for recriticality.
We should point out, however, that we do not envision having SIMMER serve as an all-inclusive code from start to finish, for all accident scenarios using one large monolithic code structure.
The vessel problem will receive the highest priority because its stage of model development is further advanced than the other two. The major areas of concern for this problem are shown in Table I.
(p. 37)
Both technical and fiscal problems must be solved before this program is feasible. These problems include the following:
V
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2189 267 a.
Availability of test facilities, b.
Availability of instruments suitable for measurements in extremely hostile environments, e.g., high temperatures.
c.
Application of scaling and similitude to out-of-pile experiments.
d.
The availability of financial resources.
The program has two stages. The first stage is developmental qualifi-cation testing, which involves close interaction with code development.
The approach to qualification testing will be to start with a number of experiments which should be thoroughly understood in their own individual scale, parameter ranges, and -imulant material combinations, both by test and analysis using mathematical models, dedicated to these experi-ments. A gradual augmentation of the complexity and accuracy of these experiments withlth'eir corresponding mathematical modeling aims at approaching the actual geometry, scale, materials and processes involved in the CDA phase under study.
Figure 2 illustrates this process in generic terms. The experiment matrices (Tables II through IV) show the parameters and processes which need to be determined or tested by experiment, as shown in the corresponding columns for the various type of experiments. These matrices are not purported to be complete and we expect them to be an evolving summary of the experimental needs for the eventual qualification of SIMMER.
The second stage of the qualification testing program is the independent qualification testing, needed before the SIMMER code can be used with full confidence in the licensing decisionmaking process.
Independent qualification testing is the stage in which emphasis is placed on determining the utility of the code for application to a full-scale reactor by providing convincing evidence to that effect to the scientific comunity.
2189 268 During this effort large scale tests will be required to prove the technical data basis on which the validity of the SIMMER results will be defended.
At the completion of this task the SIMMER Code should be capable of analyzing such large tests, in advance of their execution thus providing confidence in its validity. Modification of the code to fit specific experimental results will not be permitted during independent qualifi-cation testing (SEction VII).
A similar approach will be taken for the transition phase and single subassembly disruption problems as discussed in Section VI.
2189 269 nm, eliis III. OBJECTIVES The objective of SIMMER qualification testing is to assure that the mathematical models and input parameters are derived from experimental data, which, on the basis of criteria still to be established, are representative of the phenomena and processes governing the progression of a CDA in an LMFBR. At the present time, the work to meet this objective can be classified into three general task areas as they relate to the use of SIMMER in CDA analysis.
The whole-core energetic disassembly accident, or the " vessel problem":
The objective here is to predict the partition of the total energy release, by a postulated severe power excursion, between the primary containment and the energy absorbed through nondestructive dissipative processes.
Single subassembly accident: The objective here is to determine the pertinent phenomena and to develop the capability to assess the significance and likelihood that such accidents might propagate to involvement of larger fraction of the core.
The whole-core transition phase accident: The objective here is to advance our understanding of the phenomena and processes involved, so that reliable predictions can be made of the possible consequences of a CDA and the potential for further nuclear excursions through recriticality.
For the reasons discussed in Sections I and VI, we are placing emphasis on the vessel problem.
In this respect, an objective is to determine the confidence level to be attached to the statement that SIMMER predicts the work-energy partition in this accident scenario to be within certain bounds. Therefore, as part of this task we will develop an experimental plan that will enable SIMMER to produce reasonable estimates of the mechanical work on the sodium slug impacting the vessel or point the way l to tcode goldification.
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2189 270 IV. A BRIEF DESCRIPTION OF THE SIMMER CODE SIMMER (for S, Implicit, Multifield, Multicomponent, Eulerian, Recriti-n cality) computer code is a coupled neutronics, fluid dynamics computer program designed to analyze the dynamics of LMFBR disrupted cores.
Either point-kinetics or space-dependent neutronics models can be used to calculate neutronic feedback parameters. Multicomponent, two-phase flow models are used to calculate the large scale material motions during core disruptive accidents. The basic methodology consists of using two-dimensional time-dependent transport theory coupled to implicit Eulerian treatment of several multi-phase materials which exchange energy, momentum and mass.
SIMMER has been designed to calculate accident sequences such as whole-core energetic disassembly (vessel problem), a single subassembly disruption, and whole-core transition phase (meltdown and recriticality problem).
SIMMER-I was released in January 1977.3 The code has been used to perform scoping accident sequences and consequence calculations and has provided new insight in several important areas of LMFBR safety. These include certain aspects of fluidization during single subassembly melt-down and the generation of system kinetic energy following energetic disassembly.
As the development and application of SIMMER-I proceeded several deficiencies in the program were recognized which limited its applica-bility in certain LMFBR accident situations. Most notable among these situations was the extension of the accident initiating phase into the transition phase where the three SIMMER-I components (sodium, steel, and fuel),are not sufficient to follow intermixing of fuel from different enricnment zones or to include the effects of fission gas and control material.
Furthermore, in SIMMER-I the modeling of mass, momentum, and energy transfer phenomena has had no explicit dependence on local condi-tions, i.e., geometry, field velocities, and material properties. Thus, heat transfer and drag function correlations based on experimental 2189 271 results were difficult to use in SIMMER-I. The importance of calculat-ing the phenomena occurring during the transition phase and the impor-tance cf using experimentally-supported exchange functions dependent on local conditions to analyze fast reactor accidents led to the develop-ment of the SIMMER-II code.
The SIMMER-I fluid dynamics model is based on that developed in the KACHINA program in which the relative moticn of two fields, liquid and vapor, is calculated using the Implicit Multifield (IMF) method. The KACHINA model was extended in SIMMER-I by the addition of a third component to each field to follow the motion of the three LMFBR mate-rials:
fuel, steel, and sodium.
In addition, a structure field was added to model solid fuel, cladding, and subassembly can walls. Within each field, all materials, or components, move with the velocity of the field. This means, for example, that liquid fuel and liquid steel have the same velocity at each point in space. On the other hand, separate energy equations are solved for each component except for those components in the vapor field where the mixture of vapors is treated with a single energy equation.
As mentioned earlier, SIMMER-I was used to analyze the vessel problem.
4 A set of calculations using SIMMER was performed on energy partition and damage potential resulting from fuel vapor expansion in CRBRP (Clinch River Breeder Reactor Plant).
These calculations confirm earlier work which indicated that the expansion process is not likely to be ideal. They show that the system kinetic energy resulting from fuel vapor expansion, at the time of sodium slug impact on the reactor vessel head, may be on the order of only a few percent of the value obtained based on an isentropic expansion. This tentative result, if properly verified, would have a major impact in the assessment of CDA contribution to overall risk of LMFBRs.
2189 272 SIMMER-II, which has become available recently, represents primarily model improvements and extensions over those in SIMMER-I. The selection of features to be incorporated into SIMPER-II involve a subjective decisionmaking process and is the result of a considerable degree of engineering judgment. The basic solution method for the two-phase fluid dynamics area, primarily the exchange function models, have included both a reformulation of the model equations and improved solution techniques for these equations. On the neutronics side, the extrapolation method for the time-dependent neutron transport and diffusion equations has been eliminated in favor of the quasistatic method.
Furthermore, the capability to follow the fuel with different enrichments and the inclusion of fission gas and control material has resulted in a substantial increase in the number of components in SIMMER-II over the three used in SIMMEP... To limit the number of fuel components neces-sary to track fuel with different enrichments, the SIMMER-I fuel component has been seprated into fertile and fissile components in SIMMER-II. These two components can then model any number of fuel enrichments and burnups without having a fuel component for each enrich-ment. The addition of fission gas and control completes the components for SIMMER-II. Although control material has been introduced primarily to account for its neutronic effects, it is hoped that some understanding can be gained as to its structural and fluid dynamic role in accident analysis.
Both intragranular and intergranular fission gas components are included in SIMMER-II. These two components serve as a mechanism for predicting the fission gas release rate to the vapor field.
In the vapor field, the fission gas component contributes to the pressure field, which may provide a dispersive mechanism. Also, when the optional phase transi-tion model is used, the presence of fission gas impedes the condensation of the fuel, s, teel, sodium, and control vapor components.
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. Equally important is the improved treatment of mass, momentum, and energy transfer functions in SIMMER-II. Although the exchange functions have been oriented more towards LMFBR accident analysis,. sufficient flexitaility nonetheless is available to determine model sensitivities and to provide a means for experiment analysis.
A major aspect of the improved exchange function treatment is the struc-ture configuration model. The first function of this model is to deter-mine the geometric arrangement of the structure field energy components.
Although this arrangement is dependent on the infonnation the user provides to the model in general, the fuel pins and the subassembly can wall provide the basis for the arrangement of the components.
The mode then determines the order in which the frozen core materials are layered on the pin and can wall structures. The second function of the model is to compute from this, the heat flow paths, layer thicknesses, heat transfer coefficients, and contact surface areas for the layered components. At the same time, the structure configura-tion model serves to define the exterior structure surfaces seen by the flow fields, including the surface heat transfer coefficients and surface areas. The final function of the model is to adjust the hydraulic diameter for the loss or gain of solid material in the structure field due to melting or freezing and plugging.
For the present, the flow regime treatment of SIMMER-II remains the same as in SIMMER-I; i.e., the liquid field is treated as dispersed droplets except when low vapor volume fractions occur.
In this case a bubbly flow regime is used for phase transitions.
SIMMER-II is in:. ended to provide for better and more complete modeling of the physical processes as well as more flexible computational and data management schemes. A critical assessment of the models used in SIMMER-II will be contained in reference 10.
The basic structure of SIMMER allows it to be adapted for the analysis of cores containing fuels associated with a variety of fuel cycles.
W V8iS 2189 274 V.
RELATIONSHIP OF THE QUALIFICATION TESTING PROGRAM PLAN TO SIMMER DEVELOPMENT The basic approach to SIMMER qualification testing is the methodical step-by-step optimization of experimental and analytical efforts under-way or planned at facilities of several NRC contractors. Two stages of SIMMER qualification testing are planned in order to reach the maturity required for its use in the licensing process. These two stages of qualification testing are developmental and independent quaiification testing.
Figure 1 illustrates the basic plan for SIMMER qualification testing.
Developmental qualification testing is the phase in which the interaction between the code development and experimental groups is very close and continuous, and its scope includes the following:
a.
definition of experimental needs for qualification testing, b.
design and modeling of experiments, c.
development of a data bank, d.
comparison and correlation of analytical with experimental results and modification or addition of models as indicated, e.
development of methods to assess the uncertainties of the results and the significance of nonprototypicalities of the experiments, f.
development of scaling laws and justification of simulation, g.
doctImentation of all experimental and analytical results, and reporting of results to the scientific conmunity.
Independent qualification testing is the phasa in which emphasis is placed on determining tha utility of the code for application to a full-scale reactor by providing convincing experimental and analytical evidence o that effect to the scientific community.
2189 275 n
Modifications of the code to fit specific experimental results will not be permitted during independent qualification testing. Once develcpmental qualification testing has been completed, all computer runs of SIMMER as part of the independent qualification testing will be performed under a rigidly controlled set of rules permitting modifications to the code only as a part of a different issuance of the code.
The scope of the independent qualification testing includes the following tasks:
a.
Audit of the code and its developmental qualification testing, b.
Selection of additional experiments, establishment of modeling bases and scaling laws aimed at defining the interactive processes dominant in various CDA sequences.
c.
Sensitivity studies to help set the qualific cion testing acceptance criteria.
We are at the beginning of the SIMMER developmental qualification testing.
In order to develop an experimental program for SIMMER qualification testing, it is necessary to establish the technical information required for this purpose.
In order to do that, it is important that an inventory of present state-of-the-art knowledge is made resulting in a detailed understanding of what has to be done to obtain the missing technical information.
The developmental qualification testing is comprised of two major aspects:
input parameters and analytical models.
Both of these aspects will be supported by the experimental program, which we are in the, process of developing.
Such an experimental program would includdthefollowingthreetypesofexperiments:
2189 276 experiments directed towards establishing the basic phenomenology a.
involved in important CDA processes, b.
separate effects experiments directed towards testing specific aspects of the code, either in terms of specific parameters or models.
In many instances, it will be very difficult to design such experi-ments.
Instead, a series of interactive tests will have to be devised so that the separate effects or microprocesses may be extracted by a combination of experimental data and calculations.
The basic approach here would be to attempt to relate the physical processes involved in the microphenomena to the global processes that may be observed in terms of parameters accessible to experi-mental observation and measurements, and proof-tests directed towards testing large scale CDA aspects c.
involving interactive modes of various processes for which a good level of confidence in predicting them analytically has been achieved.
SIMMER development is still in progress, particularly in the transition phase and single subassembly disruption areas. The planned experimental p.rogram will have a continuing and important contribution to the develop-ment effort as well. As part of this program certain experiments will be specifically earmarked towards providing us with better understanding of the basic processes in the transition phase and single subassembly disruption problems. Thus, realistic models of these processes can be developed for use in SIMMER.
2189 277 Si:, V8iS Ideally, one may argue that development should be totally complete before we embark into the qualification testing program. The reali-ties, however, in developing and testing a complex code s'uch as SIMMER for use in the licensing process, within the time and financial constraints we must recognize, dictate a reasonable, realistic depar-ture from this approach; and this program plan is intended to provide the required iterative approach.
We have come to recognize that code development and qualification testing will be closely intertwined in many instances; and as qualification testing proceeds, code changes or additions may be made to include phenomena and processes not presently included in SIMMER. We also recognize that the development and qualification testing requirements for SIMMER will vary depending on the particular accident sequence chosen for analysis using SIMMER, e.g., the phenomenology and exchange processes involved in an energetic dis-assembly may be different from those involved in a transition phase meltdown or recriticality.
For the near term needs we will concentrate on eight primary areas of We believe that these areas of concern, shown in Table I(5) concern.
represent a good starting point for our planning of the SIMMER verifica-tion for the vessel problem.
We must emphasize that the early focus on the vessel problem is not intended to imply that SIMMER as a whole will be tested by its qualification testing for the vessel problem.
It should be pointed out that SIMMER can be adapted to a particular scenario under con-sideration by inserting the appropriate subroutines, as discussed in Section IV. We do not envision having SIMMER serve as an all-inclusive code from start.to finish, for all accident scenarios using one large monolithic code structure.
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2189 278 VI.
DEVELOPMENTAL QUALIFICATION TESTING PLAN The current emphasis on the vessal problem will continue and the experimental qualification testing program will be tailored to reflect this emphasis. The reason for this emphasis is that, regardless of the particular scenario or accident sequence, the ability of the reactor vessel to acconinodate mechanical loads generated as a result of a CDA is obviously an important safety question.
If its integrity can be assured, then certain licensing decisions may be made with increased confidence. While the emphasis of the qualification testing program will be placed on the vessel problem, which SIMMER is currently developed to analyze best, certain effort will also be devoted towards developing analytical models which would provide us with a better under-stood formulation of the thermohydrodynamic processes in the transition phase scenario. A similar effort will be devoted to the development of models for sutassembly disruption.
The basic goal of the SIMMER qualification testing program is illustrated by considering the vessel problem in 3 highly simplified form:
Assume that the total amount of energy released by an extreme excursion is known. This quantity, Efission, will be partitioned by processes of mass, momentum and energy transfers. Only a portion of this energy will be available to do work on the containment; primarily this portion is characterized by the kinetic energy of the sodium slug when it impacts the reactor vessel head.
The qualification testing program has the goal of establishing the degreee of confidence in the prediction by SIMMER of the fraction of E
transformed into the kinetic energy of the sodium slug as it fission impacts the reactor vessel head. The lower this fraction, the lower
'the accuracy needed.
2189 279 L. d i.
The approach to qualification testing will be to start with a number of experiments which should be thoroughly understood in their own individual scale, parameter ranges, simulant material combinations, both by test and analysis using mathematical models, dedicated to these experiments. A gradual augmentation of the complexity and accuracy of these experiments with their corresponding mathematical modeling should be aimed at approaching the actual geometry, scale, materials and processes involved in the CDA phase under study.
Figure 2 illus-trates this process in generic terms. This process indicates the augmentation of both experiment and analysis as one proceeds from the first stage of experimentation and analysis (E and A respectively) to j
j what will ultimately be the SIMMER representation of the actual full-scale core. The aggregate nonprototypicalities between the first stage of experiment and the corresponding part of the actual full-scale core is designated as AP.
The subincremental differences in nonprototypi-calities from one stage to the next are designated as a Pi (where i = 1 through n - 1). Therefore, this series of progressively augmented expariments and corresponding analytical models would each have a clearly identifiable addition of features bringing both experiment and analysis closer to the actual CDA process involved. Ultimately this will result in a test qualified SIMMER model. This approach is suit-able for both model qualification and parameter estimation.
As a part of the continuing assessment and evaluation of this plan, experiments proposed in support of SIMMER qualification testing and development will be evaluated by the Research Review Group and recommendations submitted to ARSR. The criteria for accepting or rejecting proposed experiments will include the following:
a.
Technical need.
Such need will be determined by:
7, i
(1) technical bases cited and discussed by the Research Review Group, and (2) results of sensitivity studies, b.
Technical and economic feasibility.
Considerations in meeting this criterion include:
(1) availability of experimental facilities. Therc are technical as well as fiscal aspects of this problem. The technical aspects include design and proper instrumentation of large experiments, and the containment of large destructive tests, such as multisubassembly tests.
The fiscal aspects of the problem of course relate to the availability of funding consistent with national policies, regarding breeder reactors.
(2) timeliness of performing and completing the experiment, (3) availability of instruments and diagnostic equipment needed for effective data acquisition, and experimental error estimates, (4) estimate of the accuracy needed for analytical purposes, and (5) availability of financial resources. An uninterrupted substantive level of funding will be a crucial determinant or the successful and timely completion of this task.
2189 281 The experiment matrices (Tables II through IV) show the parameters and processes which need to be determined or tested by experiment, as shown in the corresponding columns for the various types of experiments.
These matrices are not purported to be complete and we expect them to be an evolving summary of the experimental needs for the eventual qualifi-cation of SIMMER.
The areas of concern that will have to be addressed in these experiments include:
a.
Accuracy of measurement and quality of diagnostic equipment.
b.
Application of similitude and dimensional analysis.
c.
Analysis of error propagation.
.ne progression of these experiments along with their collateral analyt-ical efforts will be in general as that shown in Figure 2.
Figure 3 shows a specific example of this approach as applied to experiments planned at ORNL as part of the Aerosol Release & Transport Program.
Examples of experiments related to the transition phase include those shown in Tables II - IV with a designation TR in the upper right corner of each appropriate block of the matrix.
Examples of such experiments already in progress for some other reason, or proposed for the future specifically for SIMMER development, include flow regime development and transition, pool dynamics, freezing and plugging mechanisms, multicomponent condensation, and dynamic fuel / cladding interactions.
A similar approach to that for the transition phase will be taken towards achieving an understanding of the processes and phenomena associated with a single subassembly disruption.
Experimental needs for the understanding of single subassembly disruption processes, which
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g may not be accommodated by experiments for the vessel and transition phase categories will be identified and incorporated in Tables II - IV in a revision of this plan.
It should be noted that Table IV summarizes the experiments needed for the purpose of verifying basic assumptions which are part of SIMMER.
This is an important part of the qualification testing plan in that it will provide us with the dat; basis needed to defend basic assump-tions related to modeling of fuel coolant interactions, upper core structure behavior during a transient, and importance of self-mixing.
Throughout this experimental program there wil' be a continuing need for the proper instrumentation of experiments so that the maximum useful information is extracted from them. Therefore, once the experimental plan has been developed and the specific experiments have been designed, it will be necessary to assure that suitable instruments are available or developed to extract the information needed to test a model or esti-mate a parameter. The importance of this cannot be overstated. We will place commensurate priority to the development of special purpose instrumentation.
Identification of such development needs will be made as soon as possible, to allow for ample lead time.
For in-pile experiments involving complex thermal-hydraulic and hydro-dynamic processes, strong consideration will be given to the performance of out-of-pile supporting or mock-up tests. Analysis and understanding of these experiments would precede the in-pile experiment. Once a good analytical model of the experiment has been achieved then a comparison of that model accounting for nonprototypicalities including scaling and similitufe effects with the corresponding model used in SIMMER can be meaningful and productive. Methods to assess the uncertainties of the results and the significance of nonprototypicalities of materials, scale, and temperature regimes will be established, understood and consistent with practices accepted by the scientific conununity.
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2189 283 A continuous and timely reporting of results to the scientific comunity will be an integral and important part of the developmental qualification testing in order to encourage the widest possible disseminacion, critical review, and discussion of the results.
Sensitivity analyses are expected to be important in developing priorities. Revisions to SIMMER may be expected as more is learned and new models are developed.
2189 284 e re
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t VII. INDEPENDENT QUALIFICATION TESTING PLAN Independent qualification testing is the phase in which emphasis is placed on determining the utility of the code for application to a full-scale reactor by providing convincing experimental and analytical evidence to that effect to the scientific community.
Modifications of the code to fit specific experimental results will not be permitted during independent qualification testing. Once developmental qualification testing has been completed, all computer runs of SIMMER as part of the independent qualification testing will be performed,under a rigidly controlled set of rules, permitting
.t eRis mod {;fications t'o the code only as a part of a different issuance of the code.
The scope of the independent qualification testing as discussed earlier in Section V includes the following tasks:
a.
audit of the code and its developmental qualification testing, b.
selection of additional experiments, establishment of modeling bases and scaling laws aimed at testing the interactive processes dominant in various CDA sequences.
c.
sensitivity studies to help finalize the qualification testing acceptance criteria.
In additidn, a code uncertainty study will be performed which will include the following tasks:
a.
Define cod.e input parameters which contain uncertainties and which can affect code output significantly, b.
defir.e uncertainty range and probability distribution for these input parameters, 2189 285 c.
perform the code uncertainty study, and obtain the influence coefficients for each of the selected parameters, and d.
a safety margin analysis which will basically entail combining the results of sensitivity studies on safety research findings and conservative assumptions used in licensing, with the results of the code uncertainty studies, to determine the margin of safety.
The independent qualification testing program plan has not been developed yet in detail, and it will be incorporated in a revision of this document as we proceed with the program.
Its basic plan is shown in Figure 4.
It is important to point out at this stage the need for t~-. facilities suitable for performing large proof-tests mentioned earlier. Their importance is critical to a full-fledge qualification testing program for SIMMER.
There is a very substantial need for testr at the subassembly scale or slightly larger. Phenomena associated with subassennly scale behavior such as can wall melt-through or ejection into the uppr plenum, or freezing and plugging, etc., are sensitive to boundary conditions such as heat loss through the side walls, frictional pressure Pop per unit length of travel and over-all material heat content. Because of strength limitations it is usually impossible to scale all the important properties.
For this reason proof tests at the subassembly scale will be needed; and, to provide appropriate thermal boundary conditions, the subassembly may have to be surrounded by partial subassemblies. Such test capabilities are the central function of the STF test reactor proposed as part of DOE's SAREF program.
We ha fe developed a comprehensive listing of the existing experimental facilities and those to be needed.6 Tables V and VI show the specifica-tions of such facilities, as well as the gaps in serving the experimental eed f
the understanding of the dynamics of disrupted LMFBR cores.
b,o
,,,a s
,m 2189 286 If important gaps in needed data remain, then it will probably be necessary to use SIMMER to generate bounding cases similar to the evaluation models for LWR-ECCS performance studies, instead of as a best estimate code.
Suggestions have been made that large scale integral tests might fill such gaps. The relative success of the large scale KIWT-TNT test and 8
of the earlier G0 DIVA tests are responsible for many of these suggen-tions. Had these tests resulted in substantial progress in under-standing core disruptive accidents, there would be little debate over
.the need for their continuation. Though the tests were successful, the success was very limited in scope and the utility of large scale tests continues to be a topic of discussion.
The Godiva tests were sensitive to the equation of state and to the transport cross-section of U-235. Once these values were properly adjusted it was possible to get an accurate prediction of fissior yield.
from prompt bursts using a coupled neutronics-hydrodynamics code. An additional datum was obtained on the energy partition into kinetic energy of the metal core by analysis of the results from the final, most energetic, Godiva test.
The Kiwi-TNT tests did not yield such good agreement, particularly on the energy partition, even when the equation of state was modified.
It might be rewarding to model this experiment with more recent data and codes. Some work along these lines was reported by Jackson and Bott.9 In either case the energy partition was modeled by comparison with equivalent damage done by high explosives.
It is well known that such comparkons are seriously in error from the lower rate excursions commonly considered in current LMFBR accident analysis. Moreover, both 2189 287 n.
dl>
\\0I these systems were bare and it is expected that the change to a system constrained by the reactor vessel sodium in a containment will make darcage assessment more controvers 'cl.
/
On the other hand, the scale of the Kiwi-TNT test was large enough that questions of scale effects or overlooked phenomena ought to be resolved.
The conclusion is that any such test need not be at full scale but might be at substantial portion thereof; that the key datum is energy partition which may be difficult to assess without a lot of preparatory work; and, that only a small number of such tests is likely to be run since it is a very expensive way of obtaining data.
Other large scale tests which have met with some success in this regard include SPERT, BORAX, SNAPfRAN, and KEWB, albeit thermal reactors.
The possibilitg of, the need to run large tests for the LMFBR comparable to the above will receive a great deal of attention principally as part of our independent qualification testing program.
As the qualification testing matures we will be in a better position to evaluate more precisely the need for and technical merit of large tests.
2189 288 VIII. QUALIFICATION ACCEPTANCE CRITERIA We do not as yet have criteria for determining at what point qualification has been achieved.
Ideally these criteria should be established at the outset and it is important that these criteria be deterministic in nature (consistent with the Licensing Criteria in 10 CFR Part 50, Appendix A). Probabilistic/ statistical tools may be useful in some instances and are expected to be used as appropriate.
The development of these criteria is the subject of an on-going NRC effort encompassing both LWRs and LMFBRs; preliminary findings are expected to be completed later this year as indicated in Figure 5.
2189 289 8 tf V 8 I S.
IX. SCHEDULES - REPORTING For in-place experimental programs the schedules are those appearing in the " Buff Book." For proposed programs specifically intended for SIMMER development and qualification testing, a planning schedule is shown in Figure 5.
The following major tasks are identified for planning purposes:
a.
Code input and modeling needs definition. This task is underway at LASL and 'is expected to be completed in November 1978.
I (' i Q{}
(
Check-out of statistic (a'l sensitivity analyses.
This task is under-b.
way at LASL and should be completed by August 31, 1978.
c.
Computer code qualification acceptance criteria development.
This task involves computer codes for use in the LWR and LMFBR safety programs. A paper on the subject is under preparation by RSR and is expected to be ready later this fall.
d.
Completion of this program plan by ARSR is expected in July 1978 and subsequent revisions as shown till April 1979.
e.
Analysis of on-going experiments by LASL. A tentative schedule calls for the availability of preliminary results by January 1979.
f.
Design of new experiments for SIMMER qualification testing.
Proposals expected by the end of October 1978.
g.
Definition of instrument needs. This task will involve the forma-tion of a working group with participation by our contractors as well as experts from DOE, vendors, et al., by the end of October 1978.
2189 290 Periodic reporting by LASL will provide for continuing assessment of the effectiveness of the qualification testing program for Review Group evaluation and recomendations.
A detailed description of new experiments will be presented in Appendix B in revisions of this document when this information is developed.
2189 291 1-XI.
REFERENCES 1.
Memorandum D. L. Basdekas to M. Silberberg/R. T. Curits, ASSR, dated September 14, 1977.
2.
Memorandum M. Silberberg to SIMMER Experimental Verification Research Review Group, dated July 12, 1978. Minutes of Research Review Group on SIMMER Experimental Verification Meeting on March 21-22, 1978.
3.
LA-NUREG-6457-MS, SIMMER-I: An Sg, Implicit M_ultifield, Multi-component, Eulerian, R_ecriticality, Code for LMFBR Disrupted Core Analysis, January 1977.
4.
C. R. Bell, J. E. Boudreau, SIMMER-I Accident Consequence Calcula-tions, American Nuclear Society Transactions, Vol. 27, November 27 -
December 2,1977, pp. 551-555.
5.
Letter J. Scott (LASL) to D. L. Basdekas dated February 22, 1978.
6.
Letter w/ attachments D. F. Knuth to W. H. Hannum dated March 11, 1976.
7.
A. R. Reider, " Kiwi-TNT ' Explosion'" LA-3351 (August 1967).
- 8. s ';. R. Stratton, T. H. Colvin and R. B. Lazarus, " Analysis o'f Prompt Excursions in Simple Systems and Idealized Fast Reactors,"
Proc.1958 Geneva Conf.12:
paper 431, p.196.
9.
J. i. Jackson, T. F. Bott: " Improvement and Verification of Fast Reactor Safety Analysis Techniques," C00-2571-4 (April 1975).
10.
"A Critical Assessment of SIMMER-II Models" (to be published as a LASL Report).
2189 292 APPENDIX A, ONG0ING EXPERIMENTS A brief description of on-going experiments is given on pp. 8-15 of Reference 1.
Additional details are contained in the following documents
'available on request:
1.
Advanced Reactor Safety, In-Pile Research Program. Sandia Laboratories, October 1, 1977.
2.
Fuel Aerosol Simulant Test (FAST) Plan, Oak Ridge National Laboratory, ORNL/NUREG/TM-129.
3.
Fast Reactor Safety Assessment, Accident Sequence Phenomena Studies -
Work Plan, Brookhaven National Laboratory, BNL-NUREG-22587, March 1977.
4.
Letter from J. E. Boudreau and H. H. Helmick, Los Alamos Scientific Laboratory to R. T. Curtis, NRC dated March 31, 1977.
],} 89 2.9 e
4
\\vt s
a
.4 APPENDIX B NEW EXPERIMENTS This Appendix will be compiled after the design of new experiments has been completed and approved by ARSR.
2189 294 I
DEVELOPMENTAL QUALIFICATION TESTING 4
e CODE DEVELOPMENT e EXPERIMENTAL EFFORT e DEVELOPMENT OF REQUIREMENTS e DEFINITION OF EXPERIMENTAL NEEDS
=
e SENSITIVITY ANALYSIS
- DESIGN & MODELING OF EXPERIMENTS e COMPARISON WITH EXPERIMENTS
- COEPARISON WITH ANALYSIS i
i j l
l 1
h
- DEVELOPMENT OF QUALIFICATION CRITERIA e REPORTING OF RESULTS TO SCIENTIFIC COMMUNITY s
I f N
DATA BANK e COMPUTER CODES /IHERMOPHYSICAL PROPERTIES e CORRELATIONS / EXPERIMENTAL DATA e ACCURACY / RANGE OF APPLICABILITY j
i
' f INDEPENDENT QUALIFICATION TESTING N
e USER TRIAL RUNS AND AUDIT OF DATA e FURTHER EXPERIMENTATION AND/OR DEVELOPMENT e REPORTING OF RESULTS TO SCIENTIFIC COMMUNITY e SATISFACTION OF VERIFICATION CRITERIA Nw LT1 Figare 1. Basic Plan For Simmer Qualification Testing
ANALYTICAL EFFORT A -1 A
Amp 1 A2 A1 n
n 1ST STAGE 2ND STAGE (n - 11th nth STAGE
.(
lth STAGE ANALYTICAL ANALYTICAL STAGE ANALYTICAL e
MODEL OF MODEL MODEL ANALYTICAL MODEL REACTOR CORE SIMMER SIMMER 1
EXPERIMENTAL EFFORT E
E-1
.n E1 E2 n
1ST STAGE 2ND STAGE (n - 1)th LARGE SCALE EXPERIMENTS -
EXPERIMENTS
- STAGE SIMULATION EXPERIMEN S OF ACTUAL CDA PROCESS i
s lc AP -1 2;
- c APj n
e i
Sc AP
- l I
N Figure 2. Illustration of Step-by-Step Parallel Progression in Analytical and Experimantal Efforts of Qualification Testing 00 W
N<
Ch
ANALYTICAL EFFORT 1st Stage 2nd Stage 3rd Stage 4th Stage Analvtical Model Analvtice Model Analytical Model Analytical Model eLi(uid Fragment Size
- Energy Deposition eBubble Size and eintegration of and Velocity in UO2 Movement Under Sodium Properties Distribution eTemperature of Water and Core Internal
+
eTemperature of Expanding Cloud eCondensation and Structure Materials Expanding Cloud eVapor/ Liquid Fuel Transport
- Effect of eUO2 Energy Deposi-Fraction eMass/ Heat Non-Condensibles
, tion and Expansion Exchange Rates Rates EXPERIMENTAL EFFORT
{
1st Stage 2nd Stage 3rd Stage 4th Stage f
Experiments Experiments Experiments Experiments UO Samples in CDA.
UO Samples in CDA-UO Samples in CDA.
UO Samples in CDA-2 2
2 2
Like High Energy Like High Energy Like High Energy Like High Energy States Caused to
+
States Caused to
+
States Caused to
+
States Caused to Energetically Energetically Energetically Energetically Disassemble in Disassemble in Disassemble in a Disassemble in a Vacuum (CRI-ill)
Arg n C.
Pool of Water Pool of Sodium (FAST Vesse0 (FAST Vessel)
(FAST Vessel) g Figure 3.
Illustration of Step-by-Step Parallel Progression in Experiments and Analysis Intended to Provide Understanding of UO2 Fragmentation and Vapor Bubble m
Dynamics Under Sodium - (CRI-ill and FAST Facilities at ORNL). See e
Appendix A for More Details on this Series of Experiments.
N N
1 I
INDEPENDENT QUALIFICATION TESTING OF SIMMER I g
I I
e Audit of Developmental _ Qualification g
I
~ Testing '
g
~
e Este'rnal Users' Experience i
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Research Review Group Recommendations I
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I improvements Verified g
i I
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---3----l r-------------
---1---i lUSE OF SIMMER FOR LICENSINGU g
1 I
I e Sensitivity Analysis l
1 e Uncertainty Study i
I I
g e Safety Margins of Analysis I
I Figure 4. Basic Plan For independent Qualification Testing of SIMMER 2189 298 m
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DEFINITION OF 10 31 78 03 79 ggo INSTRUME NT NEE DS - DEV OF We'k8ae Group Meetine O
Defuutoon of Needs O Recommendemone NEW INSTRUME NTS/
j SENSOR $
FIGURE 5 SIMMER QUALIFICATION TESTING PLANNING SCHEDULE FOR THE NEAR TERM
37 -
TABLEI MAJOR AREAS REQUIRING VERIFICATION FOR THE VESSEL PROBLEM ARI! A OF UNCERTAINTY DESCRIPTION 1.Self-mixing of core materials A short-time (50-60 masc) phenomenon wherein the hottest (highest pressure) regions of the core may be thermally mixed and equilibrated with the cooler regions, thereby reducing the driving pressures in the core.
2.Two-phase pressure drop and An intermediatartime (50-150 msec) phenomenon wherein the two-phaos mass flux et magnitude of the pressure drop across the two-phase mixture being forced bundle exit along the upper pin bundle inhibits blowdown of core debris into the sodium pool. The mass flux emerging from the bundle exit may be controlled by flashing at the front of the two phase slug. Two phase pressure drop and nonuniform expansion of UO2 may_ restrict flow of 2 nto Na un,til self-mixing (see above) reduces driving pressures in core.
UO i
3.Uquidliquid heat transfer
- a. upper transition region The vaporization of sodium due to ejection of fuel into transition region fuel coolant heat transfer above the subassembly exit drives the vapor expansion into the sodium poet. Thus sodium vapor is the working fluid in this ace,ident and the strength of the FCI in this region is central to the calculation of work-energy partition. Mixing processes between UO2 and Na in th,is region are important.
- b. fueksteel in the core The transfer of energy from fuel to steel in the core acts to augment early region pressure reduction in the core. This mechanism acts in concert with fuel self-mixing to reduce terNperatures and pressures.
- 4. Behavior of surrounding structure
- a. molting The major dissipative mechanisms in the work-energy calculation are
- h. mechanical response of pins associated with the upper core end upper internal structures. These in a bunde structures are subjected to extremely high dynamic loads. Should the
- c. Individual bundle motion structures fail or deform in such a way that hydraulic resistance is
- d. guide tube support and/or decreased the kinetic energy could increase significantly, core barrel support dome de8ormation s,r failure
- e. direct loading of the heed The configurationof the sodium slug which impacts the heed and the influence of cover gas pressurlastion are somewhat uncertairt.
- 5. Influence of Na distribution The base calculation was performed with no sodium present in the core region. The presence of sodium 4ilms, intsrassembly sodium, or sodium in partially voided bundles could drastically alter the result of the calculation. Furthermore the behavior of sodium films in thts environment is little known.
- 6. Late secondary burst Only about 5% of the original core inventory has been removed from the core at head impact. The configuration of fuel may be amenable to reassembly. This is difficult to study experimentally in the absence of a large facility such as STF.
- 7. Bubble behavior A considerable amount of Na is entrained during the bubble expansion.
The heat transfer and phase trensition phenomena associated with entrainment could alter the fluid dynamics in the upper pool. The shape of the bubble is important.
- 8. Thermophysical Properties A wide spectrum of material properties and p Scess parameters pertinent to all areas of concern.
2189 300
~
v
Table 11 EXPERIMENT MATRIX FOR SIMMER QUALIFICATION TESTING SUPPORTED BY ON-GOING PROGRAMS Cc EXPERIMENTS LARGE LABORATORY SCALE PARAMETER /
OUT-OF-PILE OUT OF-PILE IN-PILE PROCESS f_
3 Prompt Burst Energetics:
PBE ACPR Separate Effects e Energy / Work Conversion Experiments with stagnant Sodium f
with and without Sodium or !! alium in test capsule with one in core.
and seven pins of unirradiated UO -SANDlA.
2
- Sodium slug acceleration SRI Experiments-DOE Fuel Vapor Condensation Rates I33 CRI-ill/ FAST Experiments-Multicomponent Condensation h with/without non-condesible gases.
ORNL Rate Experiments-LASL Liquid Fuel droplet sizes and (2)
CRI-ill/ FAST Vacuum velocities resulting from Experiments-ORNL 8
Flashing Fragmentation M
(2 43 Fuel Freezing and Flow Freezing / Plugging Experiments-h "I
I Coastdown Expt. LASL Flow Regimes Boiling Pools and Hydrodynamich Dispersion Experiments-BNL (2,3,8)
Thermophysical Properties SACRD. Program _- DOE h
SPR-ill Experiments-SANDIA Equation of State Experiments-N 5AsipiA Momentum Exchange 12)
Air Liquid Drag-e Particle Distribution Interfield Area Expts. LASL e Particle Acceleration 14 C
( l Numbers in Parentheses Refer to items in Table 8.
EXPERIMENT MATRIX FOR SIMMER QUALIFICA110N TESTING TO BE ADDRESSED BY NEW PROGRAMS LARGE LABORATORY SCALE
]
PARAMETER /
OUT-OF-PILE OUT-OF-PILE IN-PILE PROCESS N
U 5I Prompt Burst Energetics:
PBE ACPR Separate Effects
- Energy / Work Conversion Experiments with flowing Sodium with and without Sodium or Helium in test capsule using one in core.
or seven pins of irradiated and f
- Sodium slug acceleration
- SRI Experiments-DOE unirradiated UO -SANDIA 2
FAST Experiments-ORNL Establish scale effects - SARE F/Dbc
% Fuel motion reactivity ramp
- Sodium distribution
- CAMEL Experiments-DOE /ANL I3I Fuel vapor condensation rates-FAST ACPR Fuel Vapor condensation rate with/without nornondensible Experinients with Sodium and experiment-one and seven pin
- '0 -Sandia,SAREF/ DOE gases structure-ORN L 2
- Bubble Dynamics ge (2,3)
ACPR UO -Steel Mixtures 8
Molten UO7 Steel Heat Transfer Thermite / Melt Experiments-2 Coefficients SANDIA Experiments-SANDIA (2.3)
ACPR UO Steel Two Phase Mixture UO Steel Heat Transfer to Structure 2
7
- Radial Heat Flux Injection Experiments-SANDIA
- Ablation Rate N
- Penetration Distance Momentum Exchange Nozzle and Shock Tube W
- l' article Acceleration Experiments-SANDIA
- Particle Distribution CD N
( ) Numbers in Perentheses Refer to items in Table 1.
Table lli (Con't.)
EXPERIMENT MATRIX FOR SIMMER QUALIFICATION TESTING TO BE ADDRESSED BY NEW PROGRAMS FERWEUS
~
LARGE LABORATORY SCALE PARAMETER /
OUT-OF-PILE OUT-OF-PILE IN-PILE PROCESS (2)
~
Fuel Freezing and Flow Channel Thermite / Melt Facilities Establish the effects of S/A Plugging Experiments-SANDIA design and test full-scale S/A-
- Fuel Crust Behavior SAREF/ DOE
- Ablation Heat Transfer
- Slurry Freezing / Blockage Formation
- Effects of: Entrained Gas Sodium Wirewraps
- Two-phase Pressure Drop and Mass Flux at Bundle Exit i
Vapor-liquid Phase Slip Flashing water source experiments S
to study vapor-liquid slip--SRl/ DOE Flow Regimes h
Test real materials-
- Boiling Pools Dynamics and Boiling Pool and Hydrodynamic SAREF/ DOE Heat Transfer Dispersion of Internally Heated
- Fission Gas Suppression of Pools Expt. - BNL Boiling N
Thermophysical Properties (2,3,s)
SACRD Program-DOE h
SPR-ill Experiments-SANDIA Equation of State Expts.
m SANDIA C
Dynamic Fuel / Cladding Interactions TREAT,SLSF Experimon'ts-g CD DOE U
Establish Effects of Intra S/d incoherence SAREF/ DOE Equilibrium vs. Non-equilbrium (e.7) FASTExpt.-ORNL SAREF/ DOE Heat and Mass Transfer Processes SRl/ DOE Assumed in SIMMER
( ) Numbers in Perenthemse Refer to items in Table 1.
EXPERIMENT MATRIX FOR SEPARATE TECHNICAL ISSUES RELATED TO ASSUMPTIONS IN THE DEVELOPMENT OF SIMMER (NEW PROGRAMS)
EXPERIMENTS LARGE L ABOR ATORY SCALE BASE OUT-OF-PILE OUT-O F-PILE IN-PILE ASSUMF TIONS Delayed Energetics:
(6)
Na FCI
- Fuel Coolant Interactions in and
- UO7Na Fragmentation Tests with
- ACPR Pre-mixed UO7 above core and without shock triggers-E x periments-St.N DI A
- Fuel Fragmentation SANDIA
- SPR ill U02 s article Injection
- Trigger Mechanisms
- F AST Tests Under Sodium with into Na Experiments-SANDI A Additional Structure-ORN L SIMMER Assumption _
No Shock Wave'in Sodium
- CRI ill/CDV in Vacuum-ORNL
- "9 Flashing water source experiments to e Significance of "Numen. cal,,
g
- "9 mixing-SRl/ DOE, Purdue SIMMER Assumption Coarse Eulerian Grid O.K.
u Behavior of Upper Core Structure W Upper core structure structural H
8 SIMMER Assumption integrity experiments - SRl/ DOE No Structural Deformation During Transient.
N s
Q<
l U
CD
( ) Numbers in Parentheses Flefer to items in Table 1.
TABLE V FACILITY FUNCTI6tlAL CAPABILITIES Class A Capabilities for fuel-pin experiments (up to 37 pins) related to fuel failure phenomenology, prompt-burst consequences, fuel-pin performance limits, and cladding and fuel motion during the initial phase of an HCDA.
Would allow full steady-state operation for preconditioning fuel with capability for both rapid (short period) and slow transients from steady-state.
The information generated relates to the realistic technical basis for limiting safety system settings and operating limits.
Class B Capabilities for single-subassembly gross fuel / steel motion experiments.
Would allow short-period (not necessarily as short as in Class A) transients from quasi-steady-state operation. Steady-state operation for 10-30 minutes to build-in short-term decay heat would be desirable.
Low power level post-burst operation desirable.
The information generated relates to the establis'hment of realistic bases for the assessment of radiologic source terms and accident energetics.
Class C Capabilities for multiple-subassembly transition phase and core-disassembly experiments. Self-driven special-purpose experiments could be the most effective way to achieve requirements.
Steady-state operation for 10-30 minutes would be desirable.
2189 305 kn>
V8is
TABLE VI Espertment and Factitty Nectdumary Pertinent Entsting fley Limitations of ster Esperiment Types Information Needs Facility Entsting facility (tes)
Needed New Capability 1.
Transtent fuel behavior Internal fuel motion prior TREAT No steady-state capability A
and fuel pin failure to failure (hig' resolution ACPR for pre-conditioning
- to provide steady-state plus transient data) capability Fission product effects ACPR (swelling, release) on fuel failure
/
A Fuel pin failure time.
ACFR location and mode 4
Time-dependent cladding 7",
loading state
-.--e Fuel mechantes (hot pressinc, La cracking,etc.)
.- 2.
Initial cladding Material motion for both ACPR Limited to 7-pin emperaments
. A and fuel motion transient overpower and with large flut depression
- to provide proper under-cooling accidents problems.
boundary conditions and high resolution and for both slow and rapid data.
heating No data on clad motion.
4 A
3.
Prompt burst effects:
Energy work conversion.
ACPR No steady-state capability
- to provtje adequate Effective equation-Itssion product effects on for pre-conditioning steady-state plus of-state; "uel fuel motion and irradiated transient operation coolant interaction fuel effective equation-of and high resolution state in prompt burst data transtents; local fuel-coolant interactions u short periods 4.
Locallred molten fuel /
Thermo-mechanical behavior ACPR Both limited in experiment A
size. Long period in TREAT
- to provide proper steel / sodium interaction (temperatures, heat transfer TREAT N
phenomenology rates,pressurtratton) prevents tests on a real boundary conditions time scale.
steady-state plus transient operation,
a Interaction configuratic-s and high resolution g
and material motion (htgh data 9
resolution data) 5.
Extended dispersive fuel Material motion on subassembly TREAf fREAf is severely limited in B
motion (sweepout, bollup) scale (medium resolution data)
SLSF/tTR emperiment stre which leads
- to provide adequate C
at low to few times full power to excessive heat losses to scale, proper boundary densttles, sodium flow history boundary. It can provide no conditions, adequate and pressurtration apprectable steady-state resolution material Q
operation to build-up motion monitoring.
Fuel / steel pluggin; and/or fission products for short-and built-in decay meltout behavtor term decay heat. SLSF/ETR heating has no fuel motion Ultimate dispc',stion and monitortng, has flux depres-coolability of fuel / steel ston problems and severely limite<1 transient rapability.
rnnq1omerate
TABLE VI (Continued)
Experiment and Facility Needs Suunary Pertinent Existing Key Limitatfors of
~
Key Experiment Types Infomation Needs Factitty ExistingFactitty(lesl Needed New Capability 6.
Rapfd fuel / steel Material motion on sub-ACPR Severely limited in experi-B expulston assembly scale at high TREAT ment size. Does not allow
- to provide adequate power densities steady state build-up of scale, proper boundary fission products for short-conditions, adequate Subasscuby can behaylor term decay heat.
resolution material ar.d failure motion monitoring.
and built-in decay Fuel / steel plugging and/or heating complete expulston Ultimate disposition and coolab111ty I
b f
7.
Re-entry dynamics Fuel / steel re-entry into TREAT TREAT is severely limited B
intact or partially failed SLSF/ETR fn experiment stre. SLSF/ETR
- to provide adequate subastembly can (ttning.
has no fuel motion monitoring scale, proper boun-rate,noncoherence) capability.
dary conditions; adequate resolution Pressurtration effects material motion monitoring, and butit-
~
in decay heating CO 8.
Multtple subassembly Subassen61y can failure SLSF/ETR Limited in experiment stre B.C I
M disrtption dynamics for this type of experiment
- to provide proper (transttlon phase)
Sross fuel / steel motion and has no fuel motion scale and adequate
,g monitoring or burst cap-efa Gross fuel / steel motion ability.
N 9.
Large-scale energetics Gross fuel / steel motion MONE B.C (FSCI. gross disassee61y)
- to provide proper Neutronics-hydrodynamics scale and direct coupling coupilng of all effects (in C)
Pressurtration effects System deformations
- 10. Accident sequence Material (sodium, steel, fuel)
TREAT See all of the above A.B.C motion through full SLSF/ETR
- to provide full sequence (LOF. TOP etc.)
ACPR range of data and to check accident modeling prototypic con-ditions
UNITE D ST ATES NUCLE AR F* E G U L A TO H Y COMVISSION f
7 W ASHING TON. D. C. 20SSS POS T A G E A ND F E Ein P AID US NUCLE A R RE GUL A TOR Y OF F ICI AL BUSINf GS cOuue556ON PE N AL T Y F OR PRIV A T E USE, $ 300 U5 N 2189 308
.