Developing a Standard Code for Spent Fuel and High Level Waste Containment Baskets

Abstract

ASME Section III, Division 3, “Containments for Transportation and Storage of Spent Nuclear Fuel and High Level Radioactive Material and Waste” currently addresses the design of transportation and storage containment shells but it has yet to address the containment internal support structure that holds the spent fuel or high level waste in place. However, the code for internal support structures, hereafter referred to by its common name “basket”, has been under development by ASME for the past 2 years. Development of the new code, to be known as Subsection WD, “Internal Support Structures” was deemed necessary because current containment system basket construction is a piecemeal approach using ASME Section III, Division 1, Subsection NF, “Supports” and/or ASME Section III, Division 1, Subsection NG, “Core Support Structures” or some other engineering method. Approvals for the various combinations are granted from the regulatory authority. The piecemeal approach tries to capture the critical elements important for a containment basket. However, Subsections NF and NG are based on nuclear power plant design which has different design goals than for a spent fuel or high level waste containment. The issuance of Subsection WD will ensure standardization of future containment baskets, assist the regulatory agency in the review and approval of the baskets, and ensure that the essential criteria in the basket related to spent fuel and high level waste storage transportation and disposal is adequately addressed. The purpose of the basket is primarily to ensure that the radioactive components in the containment are supported in a way as not to create a criticality event. Current acceptance is typically based on a no yield design that the containment manufactures all say is too conservative and based on unreasonable criteria. What should the basket design be based on, how should Subsection WD address them, etc.? The purpose of this paper is to inform interested parties of the progress that has been made in development of Subsection WD, what construction provisions it will initially include and what is planned for it, and when is it scheduled to be issued.