Sanderson & Porter have carried out a series of studies over the last four years which indicate that the pebble-bed reactor way be an attractive way to obtain low-cost power. At the request of the Atomic Energy Commission, two design studies have been carried out on this concept at the Oak Ridge National Laboratory. The first of these a preliminary design of a 10-Mw(t) reactor experiment, the PRRE, was initiated September 10, and a report on the study was issued November 1960. The second phase of the work, a conceptual design study of a 330-Mw (e) central station, was initiated November 1, and is the subject of this report.

An evaluation of two thin-walled outer tubes showed that more extensive alpha working of the billet core stock results in more uniform cladding on the extruded tube. In an effort to eliminate breakthrough and to reduce eccentricity, shift, and bending of the mandrel, two experimental coppernickel billets with Zircaloy sleeves were extruded to check a modified billet design. lt was observed that the final grain size of the unalloyed uranium core of a thin- walled outer tube is insensitive to small variations in the cooling rate from the beta-treatment temperature. An axia' load of 3000 pounds applied to a thin- walled outer tube during autoclaving was ineffective in preventing bowing of the tube. Shipping experiments demonstrated that current packaging methods of thin- walled inner tubes do not prevent bowing during transit. The fabrication of specimens for the capsule irradiation program was concluded with the shipment of sixteen specimens and excess extruded tube stock to Savannah River Laboratory. The following core compositions were represented: U-1 wt.% Si, unalloyed dingot uranium, U-0.3 wt.% Al-0.5 wt.% Si, and U-0.3 wt.% Cr-0.3 wt.% Mo. All irradiation specimens were supplied in the beta-treated condition. The mechanical behavior of Zircaloy-4-clad dingot uranium tube sections was evaluated …

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At the request of B-C Maintenance Engineering, this study was initiated to investigate the feasibility of replacing the 190-C and 105-C process water flow-meter orifices with venturi tubes. Specific aspects of the problem studied were potential flow increases, accompanying production increases, costs, and the ability of the existing 190-C pumps and motors to provide the potential flow increase.

The rail shipment of large quantities of radiocesium involves a potential accidental release of this material in a readily available form to the biosphere. The magnitude of the associated potential damage to man and his environment is evaluated in this report. The evaluation of the consequences of an accidental release of Cs-137 from the Shielded Transfer Tank, Model II (STT) assumes loss of Cs-137 to the atmosphere or to surface-water. Release to the atmosphere could result from a collision followed by fire or explosion. In the event of a fire, a small fraction of the Cs-137 vould be volatilized. An explosion would disperse the Cs-137 still adsorbed to Decalso as particulates. In either case, the material is assumed to be dispersed by atmospheric mechanisms which can be described by modified Sutton equations. The accident involving a fire or explosion assumes that 1 percent or 10 percent, respectively, of 90,000 curies of Cs-137 is dispersed in a metropolitan area. Contamination of the surrounding suburban area is also involved. Damage estimates amount to about 60 million dollars and 400 million dollars, corresponding to a 1 percent and a 10 percent release respectively. Another possible type of accident involves the release of the …