This is the second annual report of an experimental program for the investigation of the neutronics of benchmark mock-ups of LMFBR blankets. Work was devoted primarily to measurements on Blanket Mock-Up No. 2, a simulation of a typical large LMFBR radial blanket and its steel reflector. Activation traverses and neutron spectra were measured in the blanket; calculations of activities and spectra were made for comparison with the measured data. The heterogeneous self- shielding effect for $sup 238$U capture was found to be the most important factor affecting the comparison. Optimization and economic studies were made which indicate that the use of a high-albedo reflector material such as BeO or graphite may improve blanket neutronics and economics. (auth)

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Experimental studies designed to fabricate NERVA graphite fuel elements capable of cyclic operations at exit gas temperatures of approximately 4400/degree/R were continued during this report period. Carbon precursor materials, manufacturing parameters, and deposition of carbide films are included in these studies. Accomplishments include the following: three commercial powders were extruded into elements having a desirable coefficient of thermal expansion; molded graphites using low-fired filler carbons and uncured short organic fibers produced graphites having an improved strain-to-failure value; thick-walled tubes of vapor-deposited zirconium carbide were produced, and the chemical composition was determined; vapor-deposited zirconium carbide coatings were applied to fuel-element bores; experimental graphite fuel elements were hot-gas tested; uranium-loaded ion exchange beads survived a heat treatment cycle of 2800/degree/C for three hours. Organic precursor carbon studies were oriented toward modification of the CAI polymers. 2 refs., 66 figs., 23 tabs.

This summary report was prepared by RL Production Planning and Development Branch. It presents the status as of June 30, 1971 of 02 Process Development activities performed and sponsored by the Atlantic Richfield Hanford Company for the AEC Division of Production. Prior work, current accomplishments (during last half of FY 1971), and future work are covered. A summary of the Process Development costs is given on Page 4. A more detailed description of these activities is contained in ARHCO Annual Report Process Development, ARH-1968-B, June 30, 1971. The paper discusses the basic production program, environmental and regulatory technology, and waste management activities.

An analytical solution for acoustic flaw triangulation on thin spherical shells has been prepared. A FORTRAN program is provided which takes as input the differences in the arrival times of acoustic energy at the transducers and evaluates the spherical coordinates of the flaw. Only three experimental time differences need be measured. For this measurement, four transducers are required. One transducer is placed at (R, 0, 0) in spherical coordinates; the other three are spaced 90 degrees apart around the equator.