TREAT Fast-Neutron Hodoscope: Improvements in Time and Mass Resolution of Fuel Motion
The fast-neutron hodoscope at the Transient Reactor Test Facility detects fuel motion in thick opaque capsules during in-core destructive transient tests. Counts from several hundred detectors, each with rates up to a megahertz, are collected at intervals as short as a millisecond for up to tens of seconds. The large amount of data must be decoded, normalized, represented in suitable forms, and analyzed. A computer-controlled magnetic disk data acquisition system has been installed which provides shorter data collection intervals, simplifies decoding, and permits immediate data analysis. Data normalizations and representations have been developed which significantly increase the dynamic range, yield sensitive quantitative indications of fuel mass motion, and render the data intuitively comprehensible. The improved hodoscope system performance level is demonstrated by results from a recent transient test, Pinex-2, which show the quantitative evolution of fuel mass motion from 1515 MW peak reactor power through a 1 MW post-scram radiation level.
Fast-neutron hodoscope at TREAT: data processing, analysis, and results
The fast-neutron hodoscope at the Transient Reactor Test Facility is designed for the determination of fuel motion during the course of brief (0.1- to 30-sec) power transients. During the course of a transient test, data must be recorded from each of 334 hodoscope channels at count rates up to 2 million/sec each, down to millisecond time intervals. This is accomplished in a relatively reliable and inexpensive manner by displaying counts from each detector sequentially in binary code on a lamp panel, which is photographed by a high-speed framing camera, producing a film record of the transient test. After chemical development, the film is examined by a computer-controlled flying-spot scanner, and the position and density of candidate lamp images are recorded on magnetic tape. Through further computer processing, these images are sorted and decoded, and the count rate is recovered for each detector at each instant of collection time. A cathode-ray tube and a plotter, both computer controlled, are used to recreate and analyze the fuel motion history of the experiment. Analysis is directed toward fuel distortion or expansion prior to clad failure, slumping, dispersion, amount and rates of movement, post-scram relocation, and ultimate disposition of fuel.
Cognitive Correlaretes of Physics Achievement of Some Nigeria Senior Secondary Students
Some cognitive correlates of physics achievement of some Nigeria senior secondary students were considered in the study. Specifically, the study examined the relationship between measures of student’s field independency. Cognitive tasks, formal reasoning and their achievement in physics. Purposive and stratified random sampling techniques were employed to obtain a sample of 524 senior secondary two students from six education zones in Kogi State of Nigeria. Three instruments were used. They are science Reasoning Tasks (SRTs). Group Embedded Figures Test (GEFT) and Physics Achievement Test (PAT). Data analysis using multiple regressions reveals that measures of students’ fields’ independency and cognitive tasks predicted student’s achievement in physics generally. However, only measure of field independency predicted students’ achievement in physics in the higher order cognitive demand questions. Measures of formal reasoning had no significant relationship with students’ achievements in physics generally or in higher order cognitive demand questions in physics. However, the overall relationships between measures of field independency, cognitive tasks, formal reasoning and students’ achievement in physics generally and in higher order cognitive demand questions in physics were both significant. Educational implications of these findings were discussed.