Mahlon Wilson

Development of Composite Materials for Pefc bipolar Plates

Polymer electrolyte fuel cells (PEFCs) are attractive alternatives to traditional energy sources for both stationary and transportation applications, provided they can be manufactured at a reasonable cost. The most costly and problematic components of fuel cell stacks may be bipolar plates. Besides meeting cost constraints, bipolar plates must possess a host of other properties including low gas permeability, corrosion resistance, low weight, high strength, and manufacturability. While the authors have developed a baseline composite material that meets these requirements, further optimization and development have resulted in significant improvements in properties and processability.

The Effect of Electrode Ink Processing and Composition on Catalyst Utilization

Platinum surface area was chemically and electrochemically characterized using X-ray diffraction (XRD), H2S adsorption, and electrochemical techniques including half-cells and fuel cells. Electrode ink processing and composition were found to have a strong impact on observed surface area with increased processing leading to a reduction in platinum surface area. Fuel cell electrode measurements show a significant portion of the platinum may not be available. This unutilized Pt may be due to either ionic or electronic connectivity as evidence exists to support both ionic and electronic isolation.

The Evolution of the LAMPF High Power Pion Production Target Mechanisms

The Los Alamos Clinton P. Anderson Meson Physics Facilitys (LAMPFs) beam contains 800 kW of power and passes through three pion production targets in series before being deposited into an isotope production section and beam dump. The first two targets are rotating graphite rings that are radiatively cooled. The third pion production target is a water-cooled graphite slug.

Radioactivity, Shielding, Radiation Damage, and Remote Handling

Proton beams of a few hundred million electron volts of energy are capable of inducing hundreds of curies of activity per microampere of beam intensity into the materials they intercept. This adds a new dimension to the parameters that must be considered when designing and operating a high-intensity accelerator facility. Large investments must be made in shielding. The shielding itself may become activated and require special considerations as to its composition, location, and method of handling. Equipment must be designed to withstand large radiation dosages. Items such as vacuum seals, water tubing, and electrical insulation must be fabricated from radiation-resistant materials. Methods of maintaining and replacing equipment are required that limit the radiation dosages to workers. The high-intensity facilities of LAMPF, SIN, and TRIUMF and the high-energy facility of FERMILAB have each evolved a philosophy of radiation handling that matches their particular machine and physical plant layouts. Special tooling, commercial manipulator systems, remote viewing, and other techniques of the hot cell and fission reactor realms are finding application within accelerator facilities.