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Table 3

Description of environmental source terms for Finnish NPP's.

Source term name LO-NCR-APC04 OL-RHR-12
Reactor type PWR (VVER440 with ice condenser) BWR
Initiating event TRANSIENT (loss of feed-water, offsite power and service water) Loss of heat removal during planned shut-down
Description of scenario Failure of primary circuit depressurization;
Core damaged;
Corium in-vessel retention – SAM;
CONT damaged due to overpressure;
Core damaged;
Failure of RPV 8 h after accident initiation – MCCI;
Failure of filtered venting;
CONT damaged due to overpressure;
Begin of release (after end of chain reaction) 10 h (after 34 h through CONT break; height: near ground level) 6 h (after 13 h through CONT break; height: near ground level)
Duration of release 62 h (38 h through damaged CONT) 32 h (27 h through damaged CONT)
Total release
   131I 60 PBq 10 PBq
   137Cs 0.2 PBq 1 PBq
   133Xe 2 000 PBq 1 000 PBq
Radiological equivalent of 131I activitya 61 PBq 55 PBq
INES category 7 7
a

Radiological equivalent of the 131I has been calculated according to INES (2009) methodology.