Verification of ITER Safety Codes Used in Plasma Transient Analysis

Verification efforts to compare the results from the safety assessment code SAFALY (with 0-D plasma model) and the 1.5-D plasma transport code PRETOR are discussed. The SAFALY code was used for calculating safety related plasma transients documented in ITER safety reports (ITER-FDR). The PRETOR code was used for plasma performance assessments for many ITER design related problems. Four test cases are considered as a verification basis for the SAFALY-PRETOR comparison: (i) increase in fueling by a specified amount and parameter scans to explore conditions leading to a maximum fusion power transient, (ii) sudden improvement (doubling) of plasma energy confinement time, (iii) sudden injection of 100 MW of heating power into an ignited plasma, and (iv) stop of plasma fueling. Verification studies of plasma transient analysis with SAFALY and PRETOR code systems have confirmed that the significant number of results reported in safety reports [such as ITER-FDR] can be reproduced by both code systems, and that the safety reports were based on the more conservative results.