Regional Basic Professional Training Course in Korea

Regional Basic Professional Training Course (BPTC) on Nuclear Safety
S3 is representative of accidents leading to indirect (filtered) releases into the
atmosphere after about 24 hours.
The calculations for the source terms, as illustrated by the results presented in Table 16.3,
have been used to assess their radiological consequences in the environment via the
atmospheric channel (at least for S2 and S3). The magnitudes of release are
approximately 10% for S1, 1% for S2 and a few 0.1% for S3. The series of sequences
represented by S1 was considered to be physically unlikely (explosive nature) and
therefore ranked in the residual risk category, in principle not requiring any action. S3
was considered to be compatible, in level and time scale, with the application of PPI
(emergency action plan).
As the potential consequences of S2 were considered to be too difficult to control by PPI,
studies were carried out with the aim of setting up facilities to bring down the emissions
to a lower value (to one inferior or equal to that of S3), which is compatible with PPI
application.
Table 16.5.2. Calculated source term into the environment for French PWRS.
Source
Term
Rare gases
Organic iodine
(ICH3)
Core fraction inventory
Molecular iodine +
aerosol form
Caesium Strontium
S1 80 0.6 60 40 5
S2 75 0.55 2.7 5.5 0.6
S3 75 0.55 0.31 0.35 0.04
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