The end of the Cold War significantly reduced the need for facilities to handle radioactive materials for the U.S. nuclear weapons program. The LLNL Tritium Facility was among those slated for decommissioning. The plans for the facility have since been reversed, and it remains open. Nevertheless, in the early 1990s, the cleanup (the Tritium Inventory Removal Project) was undertaken. However, removing the inventory of tritium within the facility and cleaning up any pockets of high-level residual contamination required that we design a system adequate to the task and meeting today's stringent standards of worker and environmental protection. In collaboration with Sandia National Laboratory and EG&G Mound Applied Technologies, we fabricated a three-module Portable Tritium Processing System (PTPS) that meets current glovebox standards, is operated from a portable console, and is movable from laboratory to laboratory for performing the basic tritium processing operations: pumping and gas transfer, gas analysis, and gas-phase tritium scrubbing.
The Tritium Inventory Removal Project is now in its final year, and the portable system continues to be the workhorse. To meet a strong demand for tritium services, the LLNL Tritium Facility will be reconfigured to provide state-of-the-art tritium and radioactive decontamination research and development. The PTPS will play a key role in this new facility.
The improved reliability, high brightness, and short wavelength of x-ray lasers make them ideally suited for studying large, high-density plasmas of interest to the laser-fusion research community. We have been developing the neonlike yttrium x-ray laser as a probe, together with the necessary multilayer mirrors and beam splitters, to image plasmas produced at the Nova laser facility and to measure electron density. With its short-wavelength (15.5-nm) light, we can use the yttrium x-ray laser to probe plasma densities up to 1023 cm-3. At the highest magnification (30¥), the spatial resolution of our imaging system is better than 1 µm. Using the technique of moiré deflectometry, we have measured density gradients in plasmas. Using the technique of interferometry, we have probed 3-mm-long plasmas with electron densities up to 3 ¥ 1021 cm-3. Temporal blurring of plasma images remains the main limitation of our approach. Thus, we are continuing to improve our theoretical and experimental understanding of laboratory x-ray lasers. We are currently working on techniques to reduce the blurring of images by shortening the x-ray laser pulse to durations approaching about 20 ps. In the future, this important research tool can be applied to study high-density plasmas produced at the proposed National Ignition Facility. Other important applications of the x-ray laser include biological imaging of whole, live cells and other structures at resolutions superior to those obtainable by conventional optical microscopy.
March 1995 in PDF format (2352K)
and LLNL Disclaimers