[en] Means are provided to produce plasma in a chamber. A diaphragm having an externally small aperture permits ions to flow out of the chamber. The ions are focused to produce an ion beam of high current density in a very small area

[en] This paper describes the removal of a radiologically contaminated concrete pad. This pad was removed during 1979 by operating personnel under the direction of the Waste Management Program of EG and G Idaho, Inc. The concrete pad was the foundation for the Organic Moderated Reactor Experiment (OMRE) reactor vessel located at the Idaho National Engineering Laboratory (INEL). The pad consisted of a cylindrical concrete slab 15 ft in diameter, 2 ft thick, and reinforced with steel bar. It was poured directly onto basalt rocks approximately 20 ft below grade. The entire pad contained induced radioactivity and was therefore demolished, boxed, and buried rather than being decontaminated. The pad was demolished by explosive blasting

[en] A generalized least-squares algorithm which refiens a prior multi-group energy-differential neutron-reaction cross-section evaluation by addition of new experimental data is described. Complete covariance information for the prior evaluation and for the new experimentla information is required in this procedure. The result is a revised best-estimate multi-group cross-section evaluation with complete covariance information. The algorithm tests the consistency of the ew and apriori information, and it readily indicates whether the new data significantly improve the knowledge of the differential cross section. These new data need not be specific differential cross sections. Therefore, the experimenter is not limited to measurements which involve only conventional monoenergetic techniques. This opportunity suggests exploration of diverse new experimental methods, e.g., ones which can exploit the high yield and favorable neutron-energy ranges offered by certain unconventional neutron sources which have received little past attention. This method is demonstratedby the detailed analysis of several hypothetical numerical examples. The understanding of the method's potential and limitations which has emerged from the present investigation is discussed

No abstract available

[en] A Ge(Li) detector and a fission detector were used to measure elemental differential cross section excitation functions for fast-neutron gamma-ray production from iron relative to fast-neutron fission of ²³⁵U. Data were acquired at approximately 50 keV intervals with approximately 50 keV neutron-energy resolution from near threshold to approximately 2 MeV. Angular distributions for the 0.847-MeV gamma ray were measured at 0.93, 0.98, 1.08, 1.18, 1.28, 1.38, 1.59, 1.68, 1.79, 1.85 and 2.03 MeV. Significant fourth-order terms were required for the Legendre polynomial expansions used in fitting several of these angular distributions. This casts doubt on the accuracy of the commonly used approximation that the integrated gamma-ray production cross section is essentially equal to 4π times the 55-degree (or 125-degree) differential cross section. The method employed in processing these data is described. Comparison is made between results from the present work and some previously reported data sets. The uncertainties associated with energy scales, neutron-energy resolution and other experimental factors for these various measurements make it difficult to draw conclusions concerning the observed differences in the values reported for these fluctuating cross sections

[en] An evaluation of the ¹¹⁵In(n,n')/sup 115m/In reaction for the ENDF/B-V Dosimetry File is presented. This evaluation is based entirely on reported experimental differential data. Several data sets were renormalized prior to the evaluation in order to take into account recent adjustments in corresponding standard cross sections and in other nuclear parameters used for derivation of cross sections. The present evaluation is compared with the corresponding ENDF/B-IV evaluation. The value of the spectrum-average cross section for the standard neutron field resulting from thermal-neutron fission of ²³⁵U has been computed for this reaction using cross section values from the present evaluation. This computed cross section compares favorably with the result of a recent evaluation of integral data

[en] The 126-F-1 ashpit is located in the 100 F Area of the Hanford Site, in the 100-FR-2 operable unit. This waste site is managed under the Radiation Area Remedial Action (RARA) project. As such, the area has undergone routine surveillance which indicated that the site may have been improperly posted as a contamination area. The ashpit was the result of coal fired plant operations in the 100 F Area. Coal ash contains various amounts of fly ash, bottom ash, and boiler slag. From 1944 to 1971, reactor cooling water was discharged to the 107-F retention basins via an above grade pipe. This paper traversed the north edge of the 126-F-1 ash pit. Effluent leakage from the pipeline led to the formation of a pond north of the pipeline. In addition, effluent flowed south into the ashpit. Ultimately, the pipeline was removed. The area north of the pipeline was included inside the 100 F concrete marker posts and as such was posted as an underground radioactive material area. At a later unspecified date, the entire ashpit was posted ''Surface Contamination Area'', then later as a ''Contamination Area''. Routine surveys indicated that radioactive contamination levels were low. This report details efforts that lead to the downposting of the 126-F-1 ashpit from contamination area to no posting or underground radioactive material

[en] The basic mechanisms involved in a solid-plasma interaction have been studied. In order to measure the ablation rates of solid polystyrene spheres of 50 to 150 μm radii, the pellets were suspended on glass fibers and exposed to a dense (n/sub e/ approx. = 5 x 10²² m^-3), hot (T/sub e/ < T/sub i/ approx. = 120 eV) theta pinch plasma. The pellet sizes were measured before and after each 2 μs pellet--plasma interaction, and the results were plotted against several plasma parameters. Qualitative agreement with recent theoretical scaling laws was obtained. The pellet surfaces acquired a fine polish when exposed to a plasma as indicated by electron microscopy. Comparison of the ionization intensities in the ablating neutral material through the first four carbon lines indicated pellet cloud temperatures in the range of 5 eV. Both spectroscopy and streak camera photography showed that focusing a Q-switched ruby laser on the pellet during the plasma interaction produced a marked increase in the ionization intensities that was sustained long after the laser pulse. The pellet--plasma interaction alone was determined to be an inefficient means of generating x-rays. The combination pellet--plasma--laser interaction promises to be a feasible radiation source for durations much longer than those produced with only the laser--solid system

[en] The properties of materials subjected to the intense neutron radiation fields characteristic of fission power reactors or proposed fusion energy devices is a field of extensive current research. These investigations seek important information relevant to the safety and economics of nuclear energy. In high-level radiation environments, neutron metrology is accomplished predominantly with passive techniques which require detailed knowledge about many nuclear reactions. The quality of neutron dosimetry has increased noticeably during the past decade owing to the availability of new data and evaluations for both integral and differential cross sections, better quantitative understanding of radioactive decay processes, improvements in radiation detection technology, and the development of reliable spectrum unfolding procedures. However, there are problems caused by the persistence of serious integral-differential discrepancies for several important reactions. There is a need to further develop the data base for exothermic and low-threshold reactions needed in thermal and fast-fission dosimetry, and for high-threshold reactions needed in fusion-energy dosimetry. The unsatisfied data requirements for fission reactor dosimetry appear to be relatively modest and well defined, while the needs for fusion are extensive and less well defined because of the immature state of fusion technology. These various data requirements are examined with the goal of providing suggestions for continued dosimetry-related nuclear data research

[en] The application of uncertainty covariance matrices in the analysis of robot trajectory errors is explored. First, relevant statistical concepts are reviewed briefly. Then, a simple, hypothetical robot model is considered to illustrate methods for error propagation and performance test data evaluation. The importance of including error correlations is emphasized