FP distribution analysis results by severe accident analysis code
The FP distributions inside the RPV, PCV, and R/B were evaluated using MAAP and SAMPSON codes. Table 1. shows the analysis results of distribution of Cs and Sr, which are the representative FP nuclide. The large uncertainties in the analysis results of both codes are caused by variations of FP models and chemical form of FP nuclide considering evaluation model.
Table 1縲FP (Cs and Sr) Distribution analysis results (deposition amount at the time of 6 days after the accident) (unit: kg)
| Area |
Unit 1 |
Unit 2 |
Unit 3 |
| Cs |
Sr |
Cs |
Sr |
Cs |
Sr |
| Inside the RPV |
10ｽ90 |
0.4ｽ0.7 |
20ｽ150 |
13ｽ33 |
38ｽ110 |
11ｽ46 |
| Inner wall of D/W |
6ｽ29 |
0.2ｽ0.3 |
Approx. 0.9 |
0.2ｽ0.4 |
less than 0.1- 1 |
less than 0.1 |
| S/P underwater |
26ｽ74 |
0.4ｽ2 |
27ｽ130 |
3ｽ4 |
57ｽ140 |
1ｽ6 |
| Release to environment |
less than 0.1-4 |
less than 0.1 |
less than 0.1-6 |
less than 0.1-0.4 |
less than 0.1-4 |
less than 0.1 |
ｼｻReferenceｼ IRID Completion report for "Improvement of recognition regarding the internal PCV condition of the reactor vessels using severe accident progression analysis and actual plant data" ｼｽ
- Sr was basically exists in debris, other than those described above.
- FPs in gaseous form is estimated to be released by being replaced by nitrogen gas.
Those of Units 1 and 2 that exist in the S/P water were estimated to be released as contaminated water.
Those of Unit 3 in the S/P water may remain as it is or release by flowing back to the D/W side from the leak points as contaminated water.