Validation of the ALARA activation code

ALARA [Analytic and Laplacian Adaptive Radioactivity Analysis] v1.0,(1,2) a new activation code released in January 1998 and developed specifically fo r the analysis of radioactivity in fusion energy systems, has been validate d by comparison to other commonly used activation codes, FISPACT-97(3) and DKR-Pulsar 2.0(4) using the International Atomic Energy Agency [IAEA] Fusio n Evaluated Nuclear Data Library [FENDL] Calculational Activation Benchmark .(5) The solutions to the benchmark problem for both steady-state and pulse d operation have been calculated with all three programs on the same IBM RS /6000 workstation. In addition to comparing the total activity in each of t he 44 non-void zones and the isotopic contributions to the activity at spec ific spatial points, the required computing time has been compared. For the steady state problem, agreement between ALARA and FISPACT-97 for the total activity was within 2.5% in all zones at all cooling times, and within 0.5 % in most zones. For both the steady state and pulsed problem, agreement be tween ALARA and DKR-Pulsar 2.0 was within 1% in all zones and at all coolin g times where tritium inventories were not significant. The agreement betwe en ALARA and FISPACT-97 for the individual isotopic inventories in the stai nless steel first wall backplate were within 1% for all dominant isotopes a t all cooling times, while the DKR-Pulsar 2.0 results showed some significa nt discrepancies. The processing time for ALARA is 2/3 of that for DKR-Puls ar 2.0 and less than 1/5 of that for FISPACT-97. This validation exercise p roves that ALARA is an accurate and fast computational tool for the calcula tion of induced activity in fusion power systems.