The U.S. annual biomass production for food, lumber, paper, and fiber, if used exclusively for energy, would provide 25 percent of current energy requirements. The collection of unharvested wood residues and cull trees for direct use as fuel for small nearby space-heating applications-especially for peak winter conditions-is an important near-term solar energy opportunity. Improved management of hundreds of millions of acres of productive forest land is an important opportunity for the long term. Harvest of cropland residues for energy values, new biomass production using intensive short-rotation silviculture, resubstitution of natural products for petroleum-based synthetics, and forest management for large-scale production of electricity and synthetic fuels are judged to be less appropriate directions for the U.S. energy system to take.

A nuclear siting policy leading to a few, large concentrated sites, it is argued, is preferable in the long run to the present policy which could lead to many dispersed sites. Such a policy could be implemented incrementally if requirements for new nuclear generating capacity were met by adding reactors to the existing 100-odd sites. Such a concentrated nuclear siting policy would, to some extent, isolate nuclear activities while augmenting the strengths of the institutions responsible for managing them. Additionally, it would confer an element of permanence on the sites and thereby open new options fer managing low level wastes and reactor decommissioning. These actions may improve the public acceptability of nuclear energy in the United States as well as lead to a more rational contained nuclear system in the long run.

By combining arc casting and electron beam melting, spectroscopically pure tantalum and alloys, suitable for containment of molten Pu-Fe alloys, were producedo The 0. 1% W alloy was used for the first LAMPRE loading.The effects of a large number of additives on the corrosion resistance of tantalum were tested^ Additions of up to 10% tungsten gave increasing endurance« Specimens of tantalum irradiated with neutrons until 3% converted to tungsten were still satisfactory in mechanical properties for reactor use.Either tungsten or the traces of yttrium remaining after arc melting can raise the one-hour recrystallization temperature of tantalum by 400'C, Effects of internal strain, critical strain and precipitation hardening in tantalum alloys were studied., High-temperature annealed tantalum had superior corrosion resistance, while impact extruded and ironed material was better than deep-drawn metal. Mechanical tests on tantalum with added interstitial elements showed that their presence to the extent expected in LAMPRE would be unlikely to weaken the tantalum. Evidence was found that oxygen promotes plutonium attack on tantalum. Small amounts of hydrogen, nitrogen and carbon had no effect on corrosion.

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