1. Stainless steel release rate evaluation in ITER operating conditions P. Schindler- V. Blet CEA/DEN/DTN/STRI/LTCD Cadarache France

2. In order to validate this code, an experimental program has been launched in the CORELE test facility in ITER representative conditions. OBJECTIVE The Activated Corrosion Products in the Tokamak Cooling Water Systems TCWS can be of major concern as contributor to the Occupational Radiological Exposure during normal operation and to the source term in case of accident. The PACTITER code, an adaptation of the PACTOLE code developed for Pressure Water Reactor, has been used for predicting the ACP activities in the various TCWS.

3. CORELE LOOP OUTLINE

4. Release Rate Measurement Radioactive ions released in the fluid Measurement of the activity A level for each radionuclide  spectrometry Irradiated tubes Purified fluid Ion-exchange resins Pure Water

5. Influence of temperature on global release rates At 150°C the release rates are : - 22 mg/dm²/month for a primary coolant velocity of 4.12 m/s - 36 mg/dm²/month for a primary coolant velocity of 1.02 m/s. Coherent with PACTITER simulation of 23 mg/dm²/month at 150°C and 1m/s.

6. Influence of temperature on global release rates At 100°C the release rates are : –Less than 2.8 mg/dm²/month for a fluid velocity of 1 m/s. –Below detection limit for 4m/s Coherent with the existence of a solid diffusion barrier which limits corrosion

7. CONCLUSION – TEST 2004 In ITER operating conditions, 316 SS release is limited : Principally by the thermally activated solid diffusion of oxygen in a surface barrier (possibly as chromite) which reduces the potential source of release by corrosion, The mass diffusion which depends solely on Reynolds number instead of the velocity at the interface fluid/solid Planned tests are in progress in order to : assess the existence of the energy of activation of the release rate (>180 kJ/mol ?) confirm the weak influence of velocity compared to the Reynolds number on the release rate. complete the validation of the code PACTITER by including the determination of Cu release rates (2006)

8. ITER TEST MATRIX 2004-2005

9. ITER CHEMICAL CONDITIONS 2004-2005