Process radiation instrumentation

1 Process Rsdistlon Instroaeiitation. In detecting the radioactivity of the air and water systems some commercially available instruments are applicable. For those installations in which such instruments prove inadequate, modifications of currently used instruments or entirely new designs are required. 

The methods used - in detecting radiation give only relative values. Radiochemical, analyses are to be used when accurate quantitative determinations are necessary. 

To detect the particulate activity, a modification of the continuous roommonitoring system used at Brookhaven National Laboratory is used. The instrument consists of a strip of filter, aper moving across a series of openings through which air is pumped. The paper, after collecting the dust, passes in front of a mica end-window Geiger counter, where the counts are transmitted 

The air, after passing the dust-monitoring device, is passed through a C.W.S. filter and then into the annular type ionization chamber. The purpose of the second filter is to further ensure dust-free air. The annular type chamber consists of two concentric cylinders and utilizes maximum geometry by allowing the radioactive air or gas to pass through the innermost cylinder while the outer chamber is filled with argon gas at a pressure of 20 atm. 

Normally, radioactive gases and particles will be vented through the offgas system and discharged to the stack. To-detect and measure this activity, a similar arrangement as described above for the reactor air system is used. 

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Select sample size, sample processing, radiation detection instruments with peripherals, and measurement period to match detection sensitivity specifications ... 

Some NFA investigators believe that too much focus is placed on the IND post-det scenario at present. Their opinion is that, should such a catastrophe become reality, the counterterrorism enterprise of any organization had failed in a most fundamental way, and perhaps more assets should have been devoted to enhanced surveillance, improved radiation instrumentation, device detection, etc. A similar view is sometimes expressed for source NFA in the pre-det arena. Although very important to know the identity and isotopic composition of a radioactive threat, additional source analyses would perhaps provide nuclear production details, facility identification, and the time since last chemical processing. However, were the material or an assembled weapon stolen, such source information would likely be but nominally productive in attribution efforts. Indeed, only pre- or post-det (RDD) route analyses have the potential to identify terrorist personnel and places of interest, a point sometimes unappreciated by NFA programmatic efforts. 

The plant building schematic is shown in Fig. III-8. The plant includes instrumentation and control systems a system for heat removal to consumers an auxiliary power supply system and a radiation monitoring system, including process radiation monitoring, dosimetric monitoring, and environmental monitoring. 

Collecting optics, radiation detectors and some form of indicator are the basic elements of an industrial infrared instrument. The optical system collects radiant energy and focuses it upon a detector, which converts it into an electrical signal. The instrument s electronics amplifies the output signal and process it into a form which can be displayed. There are three general types of instruments that can be used for predictive maintenance infrared thermometers or spot radiometers line scanners and imaging systems. 

The methods dependent upon measurement of an electrical property, and those based upon determination of the extent to which radiation is absorbed or upon assessment of the intensity of emitted radiation, all require the use of a suitable instrument, e.g. polarograph, spectrophotometer, etc., and in consequence such methods are referred to as instrumental methods . Instrumental methods are usually much faster than purely chemical procedures, they are normally applicable at concentrations far too small to be amenable to determination by classical methods, and they find wide application in industry. In most cases a microcomputer can be interfaced to the instrument so that absorption curves, polarograms, titration curves, etc., can be plotted automatically, and in fact, by the incorporation of appropriate servo-mechanisms, the whole analytical process may, in suitable cases, be completely automated. 

In spectrophotometric analysis a source of radiation is used that extends into the ultraviolet region of the spectrum. From this, definite wavelengths of radiation are chosen possessing a bandwidth of less than 1 nm. This process necessitates the use of a more complicated and consequently more expensive instrument. The instrument employed for this purpose is a spectrophotometer. 

When the fine electron beam of a STEM Instrument passes through a specimen, it generates secondary radiation through inelastic scattering processes. When inner shell electrons of the atoms are excited, the secondary radiation signals may be characteristic of the elements present and so provide a basis for the mlcroanalysls of the small specimen regions which are irradiated. 

Adjustable Workbench (PAW) instrument assembly. The SH shown in Figs. 3.15 and 3.16 contains the electromechanical transducer (mounted in the center), the main and reference Co/Rh sources, multilayered radiation shields, detectors and their preamplifiers and main (linear) amplifiers, and a contact plate and sensor. The contact plate and contact sensor are used in conjunction with the IDD to apply a small preload when it places the SH holding it firmly against the target. The electronics board contains power supplies/conditioners, the dedicated CPU, different kinds of memory, firmware, and associated circuitry for instrument control and data processing. The SH of the miniaturized Mossbauer spectrometer MIMOS II has the dimensions (5 x 5.5 x 9.5) cm and weighs only ca. 400 g. Both 14.4 keV y-rays and 6.4 keV Fe X-rays are detected simultaneously by four Si-PIN diodes. The mass of the electronics board is about 90 g [36],... 

The radiation emitted by radioactive materials is harmful to living matter. Small quantities of radioactive isotopes are used in the process industry for various purposes for example, in level and density-measuring instruments, and for the non-destructive testing of equipment. 

The progress achieved is closely linked to the development of both powerful detectors and brilliant X-ray sources (synchrotron radiation, rotating anode). Such point-focus equipment has replaced older slit-focus equipment (Kratky camera, Rigaku-Denki camera) in many laboratories, and the next step of instrumental progress is already discernible. With the X-ray free electron laser (XFEL) it will become possible to study very fast processes like the structure relaxation of elastomers after the removal of mechanical load. 

The Instrumentation and Control Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of instrumentation and control systems. The handbook includes information on temperature, pressure, flow, and level detection systems position indication systems process control systems and radiation detection principles. This information will provide personnel with an understanding of the basic operation of various types of DOE nuclear facility instrumentation and control systems. 

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