INTRODUCTION

The primary purpose of ALARA is to calculate the induced activation caused by neutron irradiation throughout a nuclear system (including fission reactors, fusion reactors, and accelerators). The usage of ALARA is fairly straightforward, requiring little knowledge of the code’s inner workings. This Users’ Guide, however does assume that the reader is familiar with the basic problem of induced activation. Background on induced activation, and details on ALARA’s can be found in [ref. 1]. This reference will also help ensure that ALARA is well-suited to the problems that you are trying to solve.

This Users’ Guide will describe the command-line options of ALARA, input file structure and the basic support files necessary to run ALARA.

FEATURES

ALARA takes full advantage of being a newly developed code by implementing the best features of the previous generation of activation codes and, at the same time, addressing their various weaknesses. Furthermore, an entirely new set of features has been implemented and continued development will allow it to respond to the evolving needs of the entire user community. ALARA’s three main design principles are accuracy, speed, and usability. ALARA matches the previous generation of activation codes in accuracy and is much faster. This is achieved by adaptively choosing the mathematical method at the smallest resolution in order to optimize both speed and accuracy.

The following features are found individually in other activation codes (primarily FISPACT, DKR and RACC):

  • multi-point (3-D) solutions in a variety of geometries
  • accurate solution of loops in activation trees
  • exact modeling of multi-level pulsing irradiation histories
  • user-defined calculation precision/accuracy
  • tracking the accumulation of light ions

The following features are not found in other activation codes, but should be considered basic elements of any modern activation code:

  • straightforward, user-friendly input file creation
  • full, easy-to-read activation tree output (not just pathway analysis)
  • flexible output options NOW including the direct calculation of waste disposal rating and clearance indices.

The following ADVANCED features are unique to ALARA and its development history:

  • unlimited number of reaction channels
  • exact modeling of hierarchical arbitrary irradiation schedules
  • reverse calculation mode

Finally, ALARA is undergoing continuous development with many new features planned for implementation, both to increase the level of physical modeling, the range of problems which can be solved, and its ease of use. ALARA is a fully developed and validated alternative to the previous generation of activation codes.