8.31. The computer is an essential tool for modern nuclear engineering practice. Although hand calculations are valuable for instruction, concep­tual visualization, scoping, and preliminary design, the complexity of nu­clear systems demands computer calculations for final design. Hence, there is a need for computer programs to meet a wide variety of requirements. Although writing a custom program may be necessary for some applica­tions, it is first desirable to explore the availability of developed codes that will meet the need. Therefore, familiarity with the sources of available computer codes is a useful engineering tool.

8.32. An essential first step in code use is to become thoroughly familiar with the problem to be solved and to determine what codes are best for the given task. In addition to developing background from the literature, consultation with experts experienced in solving similar problems may be necessary. In the process, it is likely that code availability will be deter­mined. Our purpose here is merely to point out some common code sources should it be necessary to use them.

8.33. The National Energy Software Center at Argonne, Illinois serves as a central computer program library in the areas of reactor physics, reactor engineering, and design. Periodically, it publishes a compilation of code abstracts. The center has available for distribution to qualified users well over 1000 programs.

8.34. A second major resource is the Radiation Shielding Information Center at Oak Ridge, Tennessee (§6.159). Although the emphasis in the computer code collection is on radiation transport and shielding, much information is also provided on data analysis. User code packages are provided by the Center, which has a collection of several hundred programs.

8.35. The Electric Power Research Institute (EPRI), the research arm of the electric utility industry, is responsible for significant code develop­ment. Software packages for EPRI-sponsored work are available to mem­ber utilities and others under a licensing arrangement from the Electric Power Software Center, operated by the Power Computing Co., a com­mercial information service in Dallas, Texas.

8.36. For software not available from central collections, it is often possible to obtain packages directly from the code developer by making appropriate arrangements. However, proprietary considerations may limit availability.