Reactor physics standards: The key to successfully dealing with technical diversity

Effective and valuable reactor physics standards can be successfully developed to accommodate diversity in available calculations tools and promote improvement in existing methods. The issues encountered and lessons learned in the standard, 'Calculation of Doppler Reactivity for Use in Thermal Light Water Reactor Analysis' (now under development by the ANS 19.7 working group), demonstrate this point. With a diversity of reactor physics tools available, differing levels of user experience, and a variety of procedures for calculating reactor physics parameters important to safety, it is not surprising that there are differing levels of quality in the calculational result of the same parameters. An approach that effectively deals with this technical diversity is standardization of the calculational process. This approach assures that the user's expectations are consistently met. In order for a standard to be effective, it must recognize and address three essential elements of this process: the user, a set of codes, and associated procedures