Progress Toward NuPack, the ASME Code for Type-B Containments

Within the framework of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, (ASME B&PVC) (ASME 1992) an effort has been under way since 1978 to codify a set of rules for \"construction\" of casks for spent fuel and for radiologically similar materials referred to as high-level waste. In ASME Code usage, the term \"construction\" covers materials, design, fabrication, examination, testing, and documentation. Casks are the containment and pressure vessels that are used when radioactive materials are transported. Of the various component types covered by the ASME Code, the reactor vessel of a nuclear power plant is the component that is closest to such casks in structural characteristics and design service as well as in importance to safety. Therefore, the rules for reactor vessels appeared to be a good starting point for developing rules for casks, and ASME B&PVC Section ill, Division 1, Class 1 (that is Subsection NB) was selected in 1978 as the basis for nuclear packaging (NuPack) rules. Eventually, the ASME Board of Nuclear Codes and Standards decided to give NuPack its own Division designation. This decision led to a three-way split of Section ill into Division 1 for metal construction, Division 2 for concrete construction, and Division 3 for transportation packaging. The new paragraph designator for packaging containments, corresponding to the NB designator for Nuclear \"Class I\" Containments, is WB. A general requirements subsection, corresponding to NCA, is also included, with the designator W A. At present, the exact title and precise scope of the NuPack subcommittee and of Division 3 of,the Code have not been definitively established.