1 Alain Roupioz Jean François Labouglie Electricité de France Alain Roupioz Jean François Labouglie Electricité de France Monitoring alpha risk

2 I-Principles for declaring a working area « as alpha risk » in PWR facilities

3 Activity alpha monitoring Risk alpha areas NON YES.1 er level 2 ème level 3 ème level Risk anticipation NO Sensitive areas Fuel No alpha risk Other areas

4 First level monitoring We have to look after the spent fuel before the next shut-down in order to anticipate the possible alpha contamination risk Monitoring principles : - total alpha activity > 1 Bq / l or - activity 134 I > A MBq /t We have to look after the spent fuel before the next shut-down in order to anticipate the possible alpha contamination risk Monitoring principles : - total alpha activity > 1 Bq / l or - activity 134 I > A MBq /t Fuel

5 It is necessary to take care about possible alpha contamination risk Before the outage, it is usefull to declare if the plant has to be considered in « alpha risk » or not. Monitoring criteria - smearable alpha contamination > 8 Bq /cm² It is necessary to take care about possible alpha contamination risk Before the outage, it is usefull to declare if the plant has to be considered in « alpha risk » or not. Monitoring criteria - smearable alpha contamination > 8 Bq /cm² Fuel Risk anticipation Second level monitoring Pressurizer Reactor vessel head

6 Fuel Risk anticipation Third level monitoring It consists in checking for the presence or not of alpha contamination in areas and to declare these working places to be « in alpha risk » or not Monitoring level - smearable alpha contamination > 8 Bq / cm² on working places It consists in checking for the presence or not of alpha contamination in areas and to declare these working places to be « in alpha risk » or not Monitoring level - smearable alpha contamination > 8 Bq / cm² on working places

7 Individual and collective protection devices are adapted to alpha contamination level and working conditions Alpha risk prevention

8 Specific works Grinding works need special attention. Those principles can’t be applied Grinding works need special attention. Those principles can’t be applied

9 II-Feedback : Cattenom NPP’s outages 4 x 1300 MW units

10 Alpha contamination risks But INTERNAL EXPOSURE risk - by inhalation, - by ingestion, - by skin penetration. - no external exposure risk - no external contamination risk

11 Cattenom NPP Target No internal contaminated workers During preparation Risks analysis for: - individual protection equipements - collective protection equipements Outside workstations - Air contamination monitoring - Surface contamination monitoring

12 Cattenom NPP Target No internal contaminated workers Medical monitoring for workers - Systematic paper handkerchiefs - Faeces analysis (by samples) Communication - Inside - Outside

13 III – Cattenom results

14 Cattenom results Three outages with alpha contamination Unit 3 : 100 Bq/cm² Unit 4 : 6 Bq/cm² Unit 1 : 80 Bq/cm² Results : no internal contaminated workers But : difficulties to assess contaminated surfaces of systems ANTICIPATION is the key-concept