Application of SCALE system to nuclear and thermal review of radioactive material package designs

The purpose of this paper is to present the background and intended use of the SCALE (Standardized Cask Analyses for Licensing Evaluation) system for evaluating transport package designs. This system currently incorporates criticality, radioactive source term, shielding, and thermal computer programs. The principal idea in developing such a system is to provide a standard method for use by NRC licensees and the NRC staff in evaluating package designs. This would allow licensees to know in advance how their package designs would be evaluated. In developing the SCALE system, the following items were considered: (1) operational on both IBM and CDC computer systems; (2) readily available; (3) minimum computer core; (4) minimum running time; (5) minimum input description; (6) documentation of programs; (7) direct correlation with experiments; (8) range of applicability; and (9) publication of regulatory guides. NRC contracted with Computer Sciences Division (CSD), ORNL, to develop the control system utilizing previously developed and accepted computer programs. The control system will permit the analyst to input the minimum amount of information into SCALE. SCALE will calculate its own atomic densities, material properties, etc. unless it is overridden by the user. It is expected that the same geometry input can be utilized for criticality, shielding, and thermal calculations. It is the intent of the NRC staff that for any package design which has been evaluated using the SCALE system (within its range of applicability and in accordance with published NRC Guides) to independently verify the modeling, input parameters and output without performing additional analyses. This is expected to simplify the licensing process