An enclosed 10-acre old-field plot treated in June 1969, with chlorine-36 labeled DDT was sampled each year from 1969 through 1974 to monitor the fate of the insecticide in the soil and biota. In order to provide data on compartmentalization of DDT in the vegetation, invertebrates and vertebrates inhabiting the plot, sampling was carried out to estimate both body burdens of DDT and biomass of populations. Another aspect of this study, the determination of rates of accumulation of residues by invertebrates and vertebrates, has been reported previously (Forsyth and Peterle 1973; Forsyth et al. 1975; Peterle 1975). This report describes (a) temporal patterns of DDT residues in soil and biota from 1969 through 1974 and (b) quantities of DDT held in the soil and biotic compartments of the ecosystem. Part II of the report is concerned with translocation and accumulation of/sup 14/C-DDT.

The probabilistic approach to nuclear reactor safety is playing an increasingly significant role. For the liquid-metal fast breeder reactor (LMFBR) in particular, the ultimate application of this approach could be to determine the probability of achieving the goal of a specific line-of-assurance (LOA). Meanwhile a more pressing problem is one of quantifying the uncertainty in a calculated consequence for hypothetical core disruptive accident (HCDA) using large codes. Such uncertainty arises from imperfect modeling of phenomenology and/or from inaccuracy in input data. A method is presented to determine the confidence level in consequences calculated by a large computer code due to the known uncertainties in input invariables. A particular application was made to the initial time of pin failure in a transient overpower HCDA calculated by the code MELT-IIIA in order to demonstrate the method. A probability distribution function (pdf) for the time of failure was first constructed, then the confidence level for predicting this failure parameter within a desired range was determined.

The objective of this program was to evaluate mullite in contact with molten silicon to be used as a substrate for Honeywell's Silicon-On-Ceramic process and as a container for melting solar grade silicon. A further requirement was to fabricate respective substrates and containers. To maintain solar grade silicon purity levels, the mullite must generally introduce less than 10/sup 15/ atoms/cc of impurities. To evaluate the mullite-molten silicon interaction, a series of bodies were made with variations in density, alumina-silica ratio and glass-crystalline ratio. These materials were tested in a sessile drop technique. None of the variations stood up to extended exposure to molten silicon sufficiently to be recommended as a contaner material. However, directional solidification experiments by Jet Propulsion Laboratory suggest that, under proper conditions, contamination of the silicon by mullite containers can be minimized. To improve an already good thermal expansion match between mullite and silicon, compositional variations were studied. Altering of the alumina-silica ratio was determined to give a continuously varying thermal expansion. Thus, a composition can be selected to give the desired thermal expansion match with silicon.

A comparison is made between three different dynamic analysis methods commonly used in the analysis of nuclear facilities. The methods are applied to a typical non-reactor type nuclear facility; namely, an early configuration of the High Performance Fuel Laboratory which was to have been designed and constructed to house an automated fuel process line on the Hanford Reservation near Richland, Washington. The fuel to be handled was mixed plutonium and uranium in powder and pellet form which, therefore, required design for severe earthquake and tornado conditions. The structure is a two-story reinforced concrete shear wall building with a high bay on one end. The comparison is made for earthquake motion in the lateral horizontal direction only. The first method employs a three degree of freedom spring mass system with the masses lumped at the three floor and roof slab levels. After shears are obtained they are distributed to the shear walls in proportion to their stiffnesses. Floor and roof slabs are assumed rigid but eccentricities are accounted for in the shear distribution. The second method utilizes a pseudo three-dimensional stick model. The shear walls and horizontal floor and roof diaphram are modeled as three dimensional beam elements using the SAP …

Progress is summarized in the following areas: fissile build-up in internal blankets, reference cores, and power peaking.

Studies are described which were performed for the Near Term Hybrid Vehicle program to determine passenger car usage patterns and to correlate these trip mission characteristics with vehicle design and performance specifications. (LCL)

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.