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An essential part of the efficiency calibration of gamma spectrometers is the determination of uncertainties on the results. Although this is routinely done, it often does not include the correlations between efficiencies at different energies. These can be important in the subsequent use of the detectors to obtain activities for a set of dosimetry reactions. If those values are not mutually independent, then obviously that fact could impact the validity of adjustments or of other conclusions resulting from the analysis. Examples are given of detector calibrations in which the correlations are calculated and propagated through an analysis of measured activities.

A novel gamma-ray imaging system is demonstrated, by means of Monte Carlo simulation. Previous designs have used either a coded aperture or Compton scattering system to image a gamma-ray source. By taking advantage of characteristics of each of these systems a new design can be implemented that does not require a pixelated stopping detector. Use of the system is illustrated for a simulated radiation survey in a decontamination and decommissioning operation.

Simultaneous least-squares adjustment of calculated neutron spectra in the central cavity of SPR-III and in the Pb-[B.sub.4]C bucket at ACRR is described, and the resulting 1-MeV-equivalent fluences are compared with damage measurements in 2N2222A transistors. Index Terms--Dosimetry, fission reactor measurements, least squares methods, neutron radiation effects, neutron spectroscopy, semiconductor device radiation effects.

Experiments and calculations simulating the neutron shadow shield for a reactor-powered space vehicle are described, including calculations for a variety of shield configurations and materials, and an experimental benchmark test using a bare fast reactor. Index Terms--Fission reactors, lithium compounds, Monte Carlo methods, neutron shielding, neutron spectroscopy, radiation effects, radiation transport, space technology.

Fifth graders in suburban Philadelphia school districts spend a week at a vo-tech school exploring occupations through hands-on activities. Academic concepts are tied to vocational areas, demonstrating how classroom theory applies to the world of work. Vocational and academic teachers also learn from each other's methods. (SK)

A least squares analysis of fission neutron standard fields has been performed using the latest measurements and dosimetry cross sections for activation foils, fission chambers, and helium accumulation monitors. Discrepant nuclear data are identified and adjusted spectra for the 235U thermal fission field is presented. Comments are made on the consistency of the nuclear data for the 252Cf spontaneous fission neutron environment.

The paper demonstrates the estimation of 1-MeV equivalent (Si) neutron fluence from radiometric monitor data without prior spectrum knowledge and without estimation of the neutron fluence spectrum.

The dynamics of experimental nuclear reactors exhibit strong non-linearities, while the constraints associated with their operation embody a number of safety-related decision points and protective trips. For power maneuvering, existing control technologies include human operators, state variable feedback controllers, and digital model-based controllers. In this work, we demonstrate the use of an associative stochastic automaton as an alternative. Factors which lead to the success of the application are discussed.

Hierarchical systems incorporating intelligent controllers have been proposed for use in process control of complex systems, including nuclear power plants. In contrast to these proposals, the controllers that are used in today's operational plants are very simple, and are likely to remain so unless the industry can be convinced that more sophisticated control concepts are compatible with its demanding requirements for reliability, validation and verification. The paper analyzes these requirements and proposes a concept of system architecture that has the capacity to meet them. Essential properties of the proposed methodology are modularity of the design and distributed autonomy within each module. These features are needed to ensure a system that can be implemented and tested incrementally and which will exhibit robustness in the event of plant or control system failures that render individual controller subsystems ineffective. The design of an intelligent controller for a feedwater heater is described and provides an illustrative example of the proposed concept.

Videotapes of the catching action of 28 children aged 4 to 10 years were carefully observed from simultaneous frontal and lateral perspectives. For both one- and two-handed ball catching, three discernible modes of visual attention and limb movement spaced along a maturity continuum were determined. Only for the ten-year-olds catching two-handed did strategies of visual attention (predicting where the ball would be) and limb usage (grasping with the fingers) couple exclusively as in skilled, adult catching. Success in two-handed catching improved exponentially with age from 77% to 96%. For one-handed catching the success rate was 40% at ages 4, 5, and 6 years, 7.5 and 30% at 7 and 8 years, improving steadily to 92% at 10 years. In the middle of age range the drop in performance coincided with the highest incidence of mixed strategies. No gender differences on either strategy or performance were evident.