The neutron-induced fission cross section for /sup 242m/Am(152y) was measured at the Livermore 100-MeV electron linac in the neutron energy range of 0.01 eV to 20 MeV. Fission fragments were detected using a hemispherical fission chamber. The neutron flux was measured below 10 keV using lithium glass scintillators. Above 10 keV, the /sup 242m/Am fission cross section was measured relative to the /sup 235/U fission cross section. Below 20 eV, the data were fit with a sum of single-level Breit-Wigner resonances. Results for the distribution of fission widths, the average fission width, and the average level spacing are presented. The fission cross section in the 100 MeV range is compared with previous measurements. 11 references.

Using surface traces, scanning electron microscopy, and light microscopy, Ti-, Co-, Ni-, and Fe-base alloys were evaluated for erosion and stress corrosion cracking (SCC) after exposure at about 104{sup 0}C to the nozzle exhaust from acidified geothermal brine. Examples of erosion, SCC, and corrosion are shown. Results are evaluated in terms of synergism between erosion, corrosion, and stress. Repassivation kinetics might play a key role in the formation and growth of erosion cavities. Of the materials tested, the Ti-base alloys appear to have the best combination of resistance to SCC and erosion/corrosion in high-salinity, highly mineralized, acidified, two-phase nozzle exhaust.

The status of negative ion based neutral beam systems is reviewed. Methods of generating the negative ions of the hydrogen isotopes and the handling and acceleration of these ions are considered. The status of plans for stripping the ions and for constructing beam systems are included.

This paper describes the basic design and philosophy of a real-time, interferometer phase-detection system used on the 2XIIB and TMX magnetic-fusion experiments at the Lawrence Livermore Laboratory. This diagnostics system is now a satellite to a host computer and uses high-speed, emitter-coupled logic techniques to derive data on real-time phase relationships. The system's input signals can be derived from interferometer outputs over a wide range of reference frequencies. An LSI-11 microcomputer is the interface between the high-speed phase-detection logic, buffer memory, human interaction, and host computer. Phase data on a storage CRT is immediately displayed after each experimental fusion shot. An operator can interrogate this phase data more closely from an interactive control panel, while the host computer is simultaneously examining the system's buffer memory or arming the system for the next shot.

We discuss the statics and dynamics of large scale nuclear collective motion, with special emphasis on very-heavy-ion reactions. Compound-nucleus cross sections are calculated by use of the criterion that the dynamical trajectory for the fusing system must pass inside the fission saddle point in a multidimensional space in order to form a compound nucleus. In an effort to understand whether nuclear dissipation is dominated by two-body collisions or by the interaction of particles with the mean field generated by the remaining particles, we compare the predictions of various macroscopic approaches with those of time-dependent mean-field (Hartree-Fock) theories.

Changes in ozone and other minor constituents resulting from eleven year variations in the solar flux between 180 and 300 nm reported by Heath and Thekaekara (8) are presented. Results were computed using a one-dimensional time dependent model that allows for all major feedbacks and time delays which may result from changing photolysis rates in the O/sub x/--NO/sub x/--HO/sub x/--ClO/sub x/ system. Since the 1950's the chlorine content of the stratosphere has been increasing. The effect of this increase on ozone variability during the last two solar cycles is analyzed. Expected variations in O/sub 3/ resulting from changes in the uv flux are compared to available measurements of total O/sub 3/.

The major unresolved problem in the nuclear industry is the ultimate disposition of the waste products of light water reactors. The study demonstrates the feasibility of designing a very hard spectrum actinide burner reactor (ABR). A 1100 MW/sub t/ ABR design fueled entirely with actinides reprocessed from light water reactor (LWR) wastes is proposed as both an ultimate disposal mechanism for actinides and a means of concurrently producing usable power. Actinides from discharged ABR fuel are recycled to the ABR while fission products are routed to a permanent repository. As an integral part of a large energy park, each such ABR would dispose of the waste actinides from 2 LWRs.

The air in certain work areas at the Oak Ridge Gaseous Diffusion Plant is monitored for selected radionuclides to assure safety from toxic effects to personnel in the area. Some of the radionuclides that are determined are shown with their Radiation Protection Standard (RPS) values by means of a table. The RPS is the maximum average airborne contamination to which personnel may be exposed for one week without respiratory protection and is expressed as disintegrations per minute (dpm) per cubic meter (m/sup 3/) of air. It is desirable to make reliable measurements at a level which is 10% of the RPS to ensure that the detection limits are well below the RPS. Thorium, neptunium, plutonium, and uranium all have alpha emitting isotopes and it is their alpha activity which is measured. Results are tabulated.