ML20056C531
| ML20056C531 | |
| Person / Time | |
|---|---|
| Issue date: | 03/09/1993 |
| From: | Davis P NRC |
| To: | Catton I NRC |
| References | |
| ACRS-CT-2061, NUDOCS 9306240428 | |
| Download: ML20056C531 (2) | |
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3/9/93 DRAFT TO: Ivan Catton FROM: Pete Davis
SUBJECT:
Comments from Thermal-Hydraulics Subcommittee Meeting in Idaho Falls, March 4&5,1993
- Ivan, l
This is a brief write-up of my concerns from the subject meeting. I l
focused my attention on Vol. 3 of the RELAP 5/ Mod 3 Code Manual, which discusses the Developmental Assessment Problems.
]
4 A general concern is the state of the Code documentation. Volume 3 is still a draft document, yet it is almost three years old, and does not appear to reflect the current state of the Code. Don Solberg of the Staff admitted that the code documentation is in poor shape, but I think we should say something about it anyway in order to encourage the staff to improve this important aspect of the code.
Volume 3 includes a series of RELAP 5 calculations compared apnst both actual experiments as well as simple problems with known solutior..
Dave Bessette of the Staff gave a brief presentation of the results or.'
peer review of the documentation, which concluded that Volume 3 was adequate. I do not agree with this assessment. In particular, Bessette provided a list of criteria against which the document was reviewed, and, in answer to my question, indicated that this same criteria was used to prepare the report. I found several instances where the criteria were not followed in preparing the report, and this has resulted, in my opinion, in an inadequate report. These instances are as follows:
1.
There is very little escussion of inconstancies in the calculations.
For example, there exists a case where the RELAP 5 calculation predicted the flow rate from an experiment quite accurately, but did poorly on the vessel pressure. There is no discussion of this inconsistency.
- 2. The experimental data used for the comparisons does not include any uncertainty bands.
- 3. There is essentially no discussion of which parameters are 930624o428 93o3o9 g0 PDR ACRS CT-2o61 PDR
important, or why.
- 4. There is no discussion of any criteria for evaluating the comparisons. In other words, there is no basis given for deciding whether-a comparison is good or bad.
- 5. In some cases, Mod 2 appears to do a better job than Mod 3, but no explanation is provided.
I think we should recommend that the Staff put high priority on improving the documentation and bringing it up to date.