The ``machined parts`` casks are shipped to Hanford by Savannah River for loading with irradiated lithium alloy slugs and returned for processing. The casks have been in service for about 10 years and have shielding material more than what is required by regulations for radiation attenuation. Evaluation shows that rupture of the shell is probable for edge or corner drop, with considerable displacement of shielding. The cask would fail in a 2-hour fire of 2000 F with loss of shielding and probable dispersal of the product. Bolts securing cover to cask are inadequate in event of accident.

The growing concern of government agencies for safe shipment of radioactive materials, both in this country and in Europe, has resulted in a number of proposed regulations governing every phase of shipment including the design of the cask or container, There have been requests during the last year for increased shipments of irradiated bismuth from Hanford. This radioactive material has been shipped in the B-cask to the off-site processing plant for several years. These two factors, proposed regulations and increased demand for the product, have created a need for an engineering evaluation of the cask currently being used. While it is evident on casual inspection that the B-cask design would not meet certain requirements of the proposed regulations, it is necessary that a detailed study of the design be made to determine if modifications to the cask are practical for continued use under new regulations and whether additional casks should be of a new design as required by increased shipments of the product. The purpose of this design evaluation study is to: (a) Evaluate the integrity of the B-cask design in accordance with criteria published in document HW-76476, which is based primarily upon proposed regulations of the Atomic Energy Commission …

Self-limiting power excursion tests were made to investigate the dynamic response of the Spert II BD-22/24 expanded D/sub 2/O core. This D/sub 2/O- moderated core is comprised of 3-in.-square x 24-in.-long, highly enriched, uranium-aluminum, plate-type fuel assemblies spaced on 6-in. centers. The power excursions were initiated by stepwise reactivity insertions with the system at ambient temperature and atmospheric pressure, with no forced coolant flow, and with approximately a 50-in. D/sub 2/O head over the core. The reactivity insertions ranged from about 40 cents to 3 dollars and resulted in initial asymptotic reactor periods of from about 10 sec to 50 msec. The basic self- shutdown mechanisms are apparently thermal in nature. For initial periods longer than 600 msec, the self-shutdown is due to nonboiling processes. For initial periods less than 600 msec, steam formation contributes to the self-shutdown and is apparently the predominant shutdown mechanism for power excursions with periods less than 100 msec. Limited mechanical damage to fuel plates is not obtained in tests with periods greater than 70 msec. Extrapolation of the fuel- plate surface-temperature data indicates that partial melting of the fuel plates might occur in tests with periods of 30 msec or less. The high fuel …

This report

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From abstract: "This report describes the overall loop design and the means by which this design was developed. These include critical facility measurements, analog computer calculations, hydraulic and heat transfer computations, and the construction and operation of an out-of-pile mock-up loop to determine the dynamic characteristics of the loop."