ML19317F200
| ML19317F200 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/19/1970 |
| From: | Colmar R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Case E US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8001080914 | |
| Download: ML19317F200 (5) | |
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e AUG 19 1970 Edson C. Case, Director DRS THRU M. Rosen, Chief Systems Performance Branch, DRS OCOMER REACTOR ECCS EVALUATION A meeting has been arranged at the Idaho Nuclear Corporation Computer Center (INC) for August 19-20, IS'O to review recent results obtained by INC with RELAP-3 for the Oconee reactor plant emergency core cooling i
system (ECCS) performance. The purpose of this meeting between members
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of REC, representatives of INC, and Dr. Ishin and his consultants, I
carbiener and Allemann, is to provide a basis for a Regulatory position on the adequacy of the Oconee ECCS. The judgments necessary to arriving at this position will be guided by an evaluation of the generic problems which appear to exist in the present LOCA-ECCS analytical methods. An agenda for this meeting is attached.
15l Robert J. Colmar Systems Performance Branch
,,Od-27d f7 Division of Reactor Standards
Enclosure:
Aganda cc w/encis F. A. Morris, DRL F. Schroeder, DEL R. DeYoung DEL M. Rosen, DRS j
l T. Novak. DRL D. Ross, DEL F. Morian, DRS N. Lauben. DES Distribution:
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AGENDA FOR MEETING AT INC FOR OCONEE LOCA ANALYSIS _
1 August 19-20. 1970_
PRESENTATION OF RELAP-3B ANALYSIS OF THE OCON I.
t Double-ended cold-leg break resul's; clad temperature and core l
A.
hydraulicsDouble-ended hot-leg break results; clad temperature and core B.
hydraulics Evaluation of calculated clad temperature history C.
Correspondence with RELAP core hydraulicsDetailed pres 1.
pressure distribution, qualities, component behavio 2.
3.
Comparison with adiabatic conditione 4.
Identification of marginal points 5.
ESTABLISH AN ESTIMATED " CONFIDENCE BAND" ON TH 11.
OCONEE Evaluate and attempt to quantify judgments concerning present uncertaint 7
in the following principal areas; A.
Blowdown Hydraulics Blowdown Heat Transfer
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B.
C.
Reflooding Phase (Additional details attached)
III. CONCLUSIONS Validity of RELAP results A.
Validity of RELAP-THETA rest.lts B.
Acceptibility of Oconee ECCS performance C.
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AUG I 91970 PRELIMINARY OUTLINE OF GENERIC ECCS-LOCA PROBLEM AREAS A.
BLOWDOWN HYDRAULICS _
1.
Limitations of present blowdown codes.
Nodes a.
Number and size o' nodes in the system, in the core, and in the fuel pin and cladling.
b.
Pipe Break Flow Model effect of cold liquid bypass Moody model, Discharge coefficient, on discharge rate, CSE and other experiments, etc.
Loop Resistances and Break Location c.
Transient vs steady-state loop resistances, two-phase multipliers Pump Characteristics d.
Coastdown, Cavitation model, pressure drop with forward ard s
reverse flow, locked rotor, etc.
Heat transfer, nodes on secondary side, water seal effects f.
One-dimensional Flow Conditions in the Analysis of the Core Bubble Rise Model g.
Phenomenological or operational concept; correlations
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h.
Numerical Method of Establishing Core Mass-velocity 4
2.
Experimental Verification of Models Available Experiments and Suitability a.
Limitations of current experiments; loop vs no-loop tests, with or without core heat, etc.
b.
Verification Criteria Validity of verification parameters such as residual water in vessel, pressure decay, etc., to confirm ability to calculate local core conditions 3.
Core Thermal-Hydraulics Feedback Effects 1
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AUG 191970 4.
Characterization of Local Flow Conditions Ability to define flow regimes and to characterize local flow conditions with appropriate parameters; homogenized or ' separated two-phase flow, fully developed flow, etc.
B.
BLOWDOWN HEAT TRANSFER 1.
Transient Heat Transfer vs. Steady-State Correlations Differentiation between steady-state heat transfer and transients a.
based on power, pressure, or flow b.
Identification of heat transfer regimes during transient heat transfer; DNB, etc.
2.
Heat Transfer Correlations Ranges of applicability of correlations to core conditions a.
Criteria for fully developed flow; flow inside tubes vs bundle data; pressure transient, etc.
s b.
Parameter evaluation Property data; G-values for individual phases or homogenized average mass velocity Transition between correlations within the code format c.
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3.
Effects of System Scale C.
REFLOODING PHASE
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1.
FLECHT Tests Applicability of test results to reactor conditions a.
Degraded conditions:
Core bypass during blowdowt. (pressure gradient effect); Core bypass after blowdown (steam-binding ef fect); closed channel vs open lattice b.
Time after break to invoke FLECHT results Interrelation between blowdown code calculations and accumulator delivery 2.
Fuel Failure Flow blockage and propagation of blockage c.
I.
b.
Interpretation of flow blockage data in terms of clad temperature rise i
- c..Effect of type of blockage simulation; sleeve vs plate l
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Core Internal Maldistributions Radial flow effects due to thermal gradients, flow blockage, a.
differential steam expansion Mixing efficiency b.
Mixing of injected water with vessel fluid; condensation of vessel steam 4.
Acetraulator Performance Design flow delivery va actual refill rate a.
b.
Optimization of design in terms of i.
location
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inventory 111. discharge pressure s
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