A new type-B cask design for transporting {sub 252}Cf
A project to design, certify, and build a new US Department of Energy (DOE) Type B container for transporting >5 mg of {sup 252}Cf is more than halfway to completion. This project was necessitated by the fact that the existing Oak Ridge National Laboratory (ORNL) Type B containers were designed and built many years ago and thus do not have the records and supporting data that current regulations require. Once the new cask is available, it will replace the existing Type B containers. The cask design is driven by the unique properties of {sup 252}Cf, which is a very intense spontaneous fission neutron source and necessitates a large amount of neutron shielding. The cask is designed to contain up to 60 mg of {sup 252}Cf in the form of californium oxide or californium oxysulfate, in pellet, wire, or sintered material forms that are sealed inside small special-form capsules. The new cask will be capable of all modes of transport (land, sea, and air). The ORNL team, composed of technical and purchasing personnel and using rigorous selection criteria, chose NAC, International (NAC), as the subcontractor for the project. In January 1997, NAC started work on developing the conceptual design and performing the analyses. The original design concept was for a tungsten alloy gamma shield surrounded by two concentric shells of NS-4-FR neutron shield material. A visit to US Nuclear Regulatory Commission (NRC) regulators in November 1997 to present the conceptual design for their comments resulted in a design modification when the question of potential straight-line cracking in the NS-4-FR neutron shield material arose. NAC's modified design includes offset, wedgelike segments of the neutron shield material. The new geometry eliminates concerns about straight-line cracking but increases the weight of the packaging and makes the fabrication more complex. NAC has now completed the cask design and performed the analyses (shielding, structural, thermal, etc.) necessary to certify the cask. The cask plus the associated equipment is collectively called the NAC Californium Transport System (CTS) and consists of the cask, impact limiter, and transport skid, which is designed to mate with and provide tiedowns to a dedicated trailer. The Safety Analysis Report for Packaging (SARP) was presented to DOE regulators in late March of 1999. The questions raised by the DOE regulators are currently being evaluated by NAC and ORNL. After DOE approves the SARP and issues a Certificate of Compliance (CoC) for the cask design, NRC will start its evaluation. Fabrication will not begin until all certifications (DOE and NRC CoCs, as well as an International Atomic Energy Agency Certificate of Competent Authority for international transport) have been obtained. This project is extremely challenging because of the complexity of the design and the certification and fabrication processes. The certification process is complicated by the necessity to obtain CoCs from two different regulatory agencies.
- Research Organization:
- Oak Ridge National Lab., TN (US)
- OSTI ID:
- 20093660
- Journal Information:
- Transactions of the American Nuclear Society, Vol. 82; Conference: 2000 Annual Meeting - American Nuclear Society, San Diego, CA (US), 06/04/2000--06/08/2000; Other Information: PBD: 2000; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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