Evaluation of Possible Surrogates for Validation of the Oxidation Furnace for the Plutonium Disposition Project

[摘要] The Plutonium Disposition project (PuD) is considering an alternative furnace design for direct metal oxidation (DMO) of plutonium metal to use as a feed for potential disposition routes. The proposed design will use a retort to oxidize the feed at temperatures up to 500 C. The atmosphere will be controlled using a metered mixture of oxygen, helium and argon to control the oxidation at approximately 400 torr. Since plutonium melts at 664 C, and may potentially react with retort material to form a lower melting point eutectic, the oxidation process will be controlled by metering the flow of oxygen to ensure that the bulk temperature of the material does not exceed this temperature. A batch processing time of <24 hours is desirable to meet anticipated furnace throughput requirements. The design project includes demonstration of concept in a small-scale demonstration test (i.e., small scale) and validation of design in a full-scale test. These tests are recommended to be performed using Pu surrogates due to challenges in consideration of the nature of plutonium and operational constraints required when handling large quantities of accountable material. The potential for spreading contamination and exposing workers to harmful levels of cumulative radioactive dose are motivation to utilize non-radioactive surrogates. Once the design is demonstrated and optimized, implementation would take place in a facility designed to accommodate these constraints. Until then, the use of surrogates would be a safer, less expensive option for the validation phase of the project. This report examines the potential for use of surrogates in the demonstration and validation of the DMO furnace for PuD. This report provides a compilation of the technical information and process requirements for the conversion of plutonium metal to oxide by burning in dry environments. Several potential surrogates were evaluated by various criteria in order to select a suitable candidate for large scale demonstration. First, the structure of the plutonium metal/oxide interface was compared to potential surrogates. Second the data for plutonium oxidation kinetics were reviewed and rates for oxidation were compared with surrogates. The criteria used as a basis for recommendation was selected in order to provide a reasonable oxidation rate during the validation phase. Several reference documents were reviewed and used to compile the information in this report. Since oxidation of large monolithic pieces of plutonium in 75% oxygen is the preferable oxidizing atmosphere for the intended process, this report does not focus on the oxidation of powders, but focuses instead on larger samples in flowing gas.

[发布日期] 2007-12-31

[学科分类] 材料科学（综合）

[关键词] ARGON;CONTAMINATION;DESIGN;EVALUATION;FURNACES;HELIUM;IMPLEMENTATION;KINETICS;MELTING POINTS;METERING;MIXTURES;OXIDATION;OXIDES;OXYGEN;PLUTONIUM;PROCESSING;RECOMMENDATIONS;VALIDATION