ML20212R541
| ML20212R541 | |
| Person / Time | |
|---|---|
| Issue date: | 10/12/1986 |
| From: | Catton I Advisory Committee on Reactor Safeguards |
| To: | Boehnert P Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1864, NUDOCS 8702020703 | |
| Download: ML20212R541 (2) | |
Text
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_ October 12, 1986
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MEMORANDUM T0:
Paul Boehnert
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FROM:
I Ivan Catton
SUBJECT:
SCALING MEETING, SEPTEMBER 25, 1986, NICHOLSON LANE BUILDING, BETHESDA, MARYLAND In the spirit of timeliness, I am going to write this note without the report the meeting we attended was based on.
It is not clear that it matters as the work reported is very similar to what we heard about several months ago. I will assume that you will include a reference to the report which is soon to be a NUREG.
The stated objectives of the scaling study are tb following:
(1)
Identify important transients, (2)
Identify transient phenomena, (3) Evaluate ability of a selected scaling concept to simulate phenomena, (4) Rank and document each scaling concept.
The first two objectives are motherhood. Every study is initiated with such objectives. The next two objectives are to lead one to the universal integral facility that will answer all our concerns about the thermal hydraulics of nuclear safety.
It was clear from some of the comments (T. Knight, Ishii, Zuber and Schrock sort of) that the present path will not yield the desired integral facility.
- Further, exact similitude is impossible and, in my view, another Semi-Scale is not what we need for future studies.
The INEL researchers continue on the same path in spite of the con-tinuing criticism from their review group.
It is clear that there is a need for separate effects studies not necessarily integral facil-ities that are slow to produce data and are typically set up to run pre-conceived transients. Arguments given by the proponents of the present path (integral facility) are the following:
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T 9/25/86 Scaling Meeting October 12, 1986 (1) NRR says we need B&W full power data, (2) The options available are:
(i) MIST (ii) University of Maryland Facility.
(iii) New Facility, (3) Use new scaling to get the most cost effective results, (4)
Full power leads to a tall skinny facility, (5) Linear scaling power requirements are high.
It is not clear to me why the available options are those listed.
If one argues that it is inability to model phenomena in an acceptable way that limits our ability to predict plant behavior, then ability to predict becomes the primary goal.
It seems to me that RES needs to sponsor research that results in increased understanding and better models for the codes used to predict plant behavior.
It is also incumbent on RES to convince NRR that they do indeed understand the important phenomena and can model it. Whatever new facility is the result of the present study, it will not give exact similitude of a full scale plant. Skewed scaling requires many experimental facilities to pin down scaling trends of the many important parameters. Many experimental facilities is clearly not the answer.
If a study such as the one underway was to have preceded Semi-Scale, a much better Semi-Scale would have resulted. All integral facility designs should follow such an effort. Unfortunately, we are now past the Semi-Scale stage. A large number of facilities exist and further we know what phenomena needs study. For example, there have been no separate effects testing of downcomers (like done by the English) or upper and lower plenums. It is time for research to refocus and address the problems that are in front of us instead of appealing to data from a facility without thinking.
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