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Abstract
While many codes have been written to compute the induced activation and changes in composition caused by neutron irradiation, most of those which are still being updated are only slowly adding functionality and not improving the accuracy, speed and usability of their existing methods. [special characters omitted] moves forward in all four of these areas, with primary importance being placed on the accuracy and speed of solution.
By carefully analyzing the various ways to model the physical system, the methods to solve the mathematical problem and the interaction between these two issues, [special characters omitted] chooses an optimum combination to achieve high accuracy, fast computation, and enhanced versatility and ease of use. In addition to a set of base features, standard to any activation code, [special characters omitted] offers a number of extensions, including arbitrary hierarchical irradiation schedules and a form of reverse problem for calculating the detailed activation of specific isotopes.
The physical system is modeled using advanced linear chains, which include the contributions from straightened loops in the reaction scheme, while the truncation philosophy minimizes the discrepancies between the model and the real problem. The mathematical method is then adaptively chosen based on the characteristics of each linear chain to use analytically exact methods when possible and an accurate expansion technique otherwise.
[special characters omitted] has been successfully validated against established fusion activation codes using a standard activation benchmark problem. In addition to demonstrating [special characters omitted]'s accuracy, this validation excerise has demonstrated its speed. Furthermore, by extending the benchmark problem to validate its advanced features, [special characters omitted]'s flexibility has been proven.
With its modern computational techniques and continuing development, it is hoped that [special characters omitted] will become a widely used code for the activation analysis of nuclear systems.
