Discretization in COMP23 for SR97
Lindgren, M; Widen, H
| HERO ID | 1919338 |
|---|---|
| Year | 1998 |
| Title | Discretization in COMP23 for SR97 |
| Authors | Lindgren, M; Widen, H |
| Volume | GRA and I |
| Abstract | The discretization of the near field compartment model COMP23 used in e.g. the SR95 study is rather coarse, which results in a poor description of the first instationary phase of radionuclide release. For some nuclides the maximum release rates are somewhat overestimated. In this study, the discretization has been investigated in a systematic manner. First block 3 representing the bentonite outside the hole in the canister is divided into an increasing number of compartments. This block has in earlier calculations showed to be of major importance. In the SR95 study it was divided into three compartments and here it was increased to 6, 9, 12, and 15 compartments. The differences between the release rates are smaller for each increase, but also between 12 and 15 compartments there was some difference. The release rate decreases with increased number of compartments. It was decided to use six compartments, to achieve reasonable total number of compartments and thereby reasonable calculation times. The whole system was then studied in a corresponding way. The original discretization was found to be sufficient for all other blocks if only the total release is of interest. The final discretization was however proposed to include three compartments in block 5 and changed proportions between the size of the two compartments in block 4. The resulting discretization resulted in 19 compartments compared to the 14 compartments used in the SR95 study. The calculation time was recorded for all the studied cases. It was found that the calculation time increases in proportion to the square of the number of compartments. The calculation time increases about 20 % with the proposed discretization compared to the one earlier used. |
| Report Number | NTIS/02925338_a |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Journal: Govt Reports Announcements and Index ISSN: |
| Is Public | Yes |