Update of Environmental and Safety Analyses for the National Ignition Facility: Using a New Model to Track Target Material Usage

Gillich, D ; Tobin, M ; Singh, M ; Kalantar, D ; Brereton, S ; MacGowan, B

Lawrence Livermore National Laboratory

关键词: Us National Ignition Facility;    Uranium;    70 Plasma Physics And Fusion Technology;    Targets;    Beryllium;   

DOI  :  10.2172/15013589
RP-ID  :  UCRL-ID-146211
RP-ID  :  W-7405-ENG-48
RP-ID  :  15013589

美国|英语

来源: UNT Digital Library

【 摘 要 】

The purpose of this paper is to report the methodology and assumptions, data, and results of calculations concerning safety and environmental issues related to excursions to currently planned NIF operations. Many possible uses of NIF have been suggested over the years. While some of these possible uses have been adopted into the baseline plans for NIF, many others have not. While we do not yet know all of the possible approved uses for NIF, one of the items that would bear on whether a certain course use might be adopted or not would be its environmental and safety impact. Here we examine certain excursions from the existing planned operations to determine their environmental and safety impacts. These excursions are related to the use of ''cocktail'' hohlraums as the baseline target for ignition experiments in the National Ignition Facility (NIF) as well as possible increased utilization of beryllium and uranium. This paper also addresses the fission products produced from cocktail hohlraum use for high yield experiments. Again, this analyses does not imply an authorization to proceed with such modes of operation, or any intent to proceed beyond this analyses. A detailed analysis of a range of postulated experiments for NIF was conducted for the years 2003 through 2011. The goal was to quantify the amount of target material introduced into the target bay per year. The assumptions outlined in this paper are based on the worst-case scenario from an environmental perspective. A spreadsheet was developed to integrate all the gathered information and to calculate the total amount of materials per year. The spreadsheet was also designed as a tool for future analyses. The total amount of material was used to justify and establish a proposed upper bound for the amount of beryllium and uranium introduced into the target bay in a given year. The cocktail hohlraum and associated appendages were modeled with the neutron transport code TART98 to determine neutron fluxes within the target bay. To determine the activation and fission products from a maximum possible shot of 45 M J, the TART output was entered into ACAB98. Isotopes that are potentially most detrimental to the environment were selected from the activation and fission products calculated by ACAB. With these key isotopes, routine and beyond design basis accident scenarios were run in CAP-88 and GENII respectively to determine the applicable doses for the population and at the site boundary. From this analysis, it is concluded that the introduction of cocktail hohlraums as the base target type in high yield experiments does not increase the current safety and environmental analysis dose levels.