Many applications for advanced cooling system

Laboratory scientists and industrial partners have designed a new low-power, portable, fieldable, helium-based cooling system. Originally designed for a radiation detection system, it promises to find applications in many areas, from food refrigeration to scientific instrumentation. A patent application has been filed, and the Laboratory is seeking to license the design to industrial partners.
Key to the system is the use of microprocessors to minimize vibration; they allow the compressor's motor to become more efficient, use less energy, and last longer. Instead of environmentally harmful chlorofluorocarbons, the new system uses small amounts of helium as a coolant. The design also eliminates the use of liquefied nitrogen (LN2).
LN2 has been a potentially hazardous component of most cooling systems that are built to deliver very low temperatures--for example, those used in radiation detection systems such as medical PET scans. Cooling systems that use liquefied nitrogen also are bulky and expensive to maintain and require extensive safety mechanisms. Thus, they have been considered impractical.
The small size, low power requirement, LN2-free operation, and low vibration features of the Livermore cooling system are qualities researchers sought in a cooling system for a portable, fieldable radiation detector. Lab researchers expect their design to result in a number of portable, fieldable systems, including those for environmental monitoring and locating underground oil deposits.

Contact: Ken Neufeld (510) 423-8718 (neufeld@isd.llnl.gov).

Dismantlement approach seeks to reduce waste

This September, the Laboratory plans to begin a year-long technology development effort aimed at finding ways for the nation to dismantle its nuclear weapons with greatly reduced plutonium-contaminated waste. The small-scale effort to be conducted in the Laboratory's plutonium facility will use mechanical and thermal approaches for reducing waste. First, researchers plan to use a cutter that does not produce waste chips to open a plutonium pit that has been removed from a nuclear weapon. Then they will use a process called HYDEC (hydride-dehydride-cast), which uses hydrogen gas and heat to remove the plutonium and then casts it into small ingots for storage.
Plans call for processing about 20 to 25 pits from the DOE's Rocky Flats Plant during the prototype test period. Afterward, the resulting plutonium ingots will be returned there. The project could establish a more cost-effective, less time-intensive dismantlement procedure.

Contact: Derek Wapman (510) 422-0826 (wapman1@llnl.gov).

Lab leads manufacturing of B Factory rf cavities

The Laboratory is directing the manufacture of all radio-frequency (rf) cavities needed for operating the B Factory accelerator and detector--sometimes known as PEP-II and BaBar. The $177-million accelerator and the $75-million detector are designed to advance understanding in the field of particle physics. Located at the Stanford Linear Accelerator Center (SLAC), the B Factory is a collaboration between SLAC and the Lawrence Berkeley and Lawrence Livermore National Laboratories.
Each cavity will be 2 ft in diameter and weigh about 450 lb. The rf cavities will be powered in pairs by a l-megawatt microwave generator. The first cavity was shipped to SLAC on May 30 as part of a $4-million project spread over the next two years. In all, 26 additional rf cavities will be constructed. While conventional machining on the rf cavities is being contracted to U.S. industry, critical fabrication and assembly activities are centered in Livermore, where about 60 technicians and machinists are involved.

Contacts: Curt Belser (510) 423-2472 (belser1@llnl.gov); Mark Franks (510) 423-4434 (franks1@llnl.gov).

Workshop addresses planetary defense

An international Planetary Defense Workshop was held in Livermore May 22-26, 1995. Titled "An International Technical Meeting on Active Defense of the Terrestrial Biosphere from Impact of Large Asteroids and Comets," the event attracted about 150 scientists. After reviewing present understanding of the basic nature of the threat posed by asteroid and comet impacts, attendees gathered in working groups to examine specialized issues, including detection, tracking, and categorization of threat objects, and technologies and systems for threat object deflection and dispersion.
The workshop was co-hosted by LLNL and DOE. Sponsoring organizations were LLNL, DOE, National Aeronautics and Space Administration, Los Alamos National Laboratory, Air Force Space Command, Air Force Phillips Laboratory, Naval Research Laboratory, Russian Federal Nuclear Centers VNIITF Chelyabinsk-70 and VNIIEF Arzamas-16, Makeev State Rocket Center, the Russian ministries of Energy and Defense, China's Center of Advanced Science and Technology-World Lab (Beijing), and the World Laboratory (Erice and Geneva).

Contact: Shirley Petty (510) 422-1175 (petty2@llnl.gov).