Hazard Analysis for the High-Power APT Experiments at the LANSCE Accelerator
L. S. Waters
The Accelerator Production of Tritium Target/Blanket and Materials Engineering Demonstration and Development Project have undertaken a major program of high-power materials irradiation at the Los Alamos LANSCE Accelerator. Five experiments have been installed in the Target A-6 area, immediately before the Isotope Production facility and the LANSCE beamstop, where they will take a 1.0 mAmp-proton beam for up to 10 months. This operation is classed as a Nuclear Category 3 activity, since enough radionuclides build up in the path of the beam to exceed cat-3 threshold quantities. In the process of analyzing this buildup, it was realized that a loss of coolant accident could result in oxidation and subsequent vaporization of certain tungsten elements contained in our experiments. If this process occurs in the presence of steam, breakup of the water molecules also would provide a potentially explosive source of hydrogen, causing maximum release of radioactive aerosols to the surrounding environment. This process can occur in matter of seconds. Such a release would result in a potentially unacceptable dose to the public at the LANSCE site boundary, 800 meters from the A-6 area. The authorization basis for the operation of category three activities at the LANSCE accelerator is a Basis for Continuing Operation (BIO). In light of the new accident scenario, the existing BIO was rewritten with a complete hazard analysis, accident analysis, and formulation of Limiting Conditions of Operation for controls mitigating most serious potential accidents.
This abstract was presented at the 32nd Annual Midyear Meeting, "Creation and Future Legacy of Stockpile Stewardship Isotope Production, Applications, and Consumption", Tritium Enrichment and Production Session, 1/24/1999 - 1/27/1999, held in Albuquerque, NM.