Detector powering down

After a plant trip test, Monju restarted operation on 6th December 1995. On 8th December, power was being raised for the next plant trip tests, part of 40% electric power tests. The thermal power had reached 43% when an alarm sounded at 19 47 dueto an off-scale sodium temperature at the outlet of IHX in the secondary circuit loop C. Afire alarm (smoke detector) sounded at the same time. A sodium leak alarm in the secondary circuit followed. The plant conditions of Monju at that time are shown in Fig. 1. The presence of smoke was confirmed when the door of the piping room was opened. The plant operators decided to begin normal shutdown operations becausethey judged it was a small sodium leak had occurred. Reactor power-down operations began at 20 00. 

AH gas-fired power plants require oxygen analy2ers to ensure that air has not been drawn into the piping system. Oxygen intake can lead to the presence of an explosive mixture in the pipeline before the fuel reaches the burner or combustor 2one. When gas-fired units are located in an enclosed area, multiple ultraviolet flame detectors are used to shut down equipment and flood the area with CO2 or a chemical fire suppressant whenever a spark or flame is detected. 

The ideal scenario would be to have the power of a traditional IR analyzer but with the cost and simplicity of a simple filter device, or even better to reduce the size down to that of a sensor (such as the spectral detector mentioned earlier) or a simple handheld device. This is not far-fetched, and with technologies emerging from the telecommunications industry, the life science industry and even nanotechnology, there can be a transition into analyzer opportunities for the future. There is definitely room for a paradigm shift, with the understanding that if an analyzer becomes simpler and less expensive to implement then the role of analyzers/sensor can expand dramatically. With part of this comes the phrase good enough is OK - there is no need for the ultimate in versatility or sophistication. Bottom line is that even in process instrumentation, simple is beautiful. 

Most UV equipment operates at voltages well above the main level, and it is important to prevent exposure to high voltage by proper installation. Microwave-powered lamps have a microwave detector to detect microwave radiation leakage. The system is shut down when microwave irradiance of 5 mW/cm is detected. ... 

The setup for ESR spectroscopy is a cross between NMR and micro-wave techniques (Section 5.8). The source is a frequency-stabilized klystron, whose frequency is measured as in microwave spectroscopy. The microwave radiation is transmitted down a waveguide to a resonant cavity (a hollow metal enclosure), which contains the sample. The cavity is between the poles of an electromagnet, whose field is varied until resonance is achieved. Absorption of microwave power at resonance is observed using the same kind of crystal detector as in microwave spectroscopy. Sensitivity is enhanced, as in microwave spectroscopy, by the use of modulation The magnetic field applied to the sample is modulated at, say, 100 kHz, thus producing a 100-kHz signal at the crystal when an absorption is reached. The spectrum is recorded on chart paper. 

All reactions were performed in a cylindrical Pyrex vessel using 10 mmol of nitrone 1 and 20 mmol of dipolarophiles 2 or 4. The mixtures were introduced into the monomode reactor (Maxidigest MX 350 Prolabo) at the powers and times indicated in Table 1. Temperatures were recorded throughout the reaction using an IR detector connected to the reactor. At the end of the reaction, after cooling down and extraction with CH2CI2, products 3, 5a and 5b were analyzed by GC methods using an internal standard and authentic samples. 

There is a constant move toward the improvement of instrumentation technology. This ranges from new detector and source technologies, to new ways to make IR measurements and new ways to fabricate instruments. In the area of components, there are new MEMS-based sources, which operate at low power and provide extended source lifetimes, new tunable laser devices, new tunable filter devices, both broad and narrow range, and new detector arrays. Many of these devices are currently relatively high cost. However, most are made from scalable technologies, such as semiconductor fabrication technologies, and as such if the demand increases the cost can come down. Many can follow Moore s law of... 

Inductively coupled plasma-mass spectrometry (ICP-MS) is a powerful technique that uses an inductively coupled plasma as an ion source and a mass spectrometer as an ion analyzer. It can measure the presence of more than 75 elements in a single scan, and can achieve detection limits down to parts per trillion (ppt) levels for many elements—levels that are two or three orders of magnitude lower than those obtained by ICP-AES (Keeler 1991). It is more expensive than ICP-AES and requires more highly skilled technical operation. Aluminum levels in urine and saliva were detected down to 0.02 g/mL and in blood serum to 0.001 g/mL using ICP-MS (Ward 1989). Speciation studies have employed ICP-MS as a detector for aluminum in tissue fractions separated by size-exclusion chromatography (SEC) with detection limits of 0.04 g/g in femur, kidney and brain (Owen et al. 1994). 

Medium-resolution absorption spectrometer emission spectrometer with red-sensitive photomultiplier or CCD detector laser excitation source such as listed in Table 1 (or medium pressure mercury arc such as described in earlier editions of this text) neon calibration lamp and power supply (available from, e.g.. Oriel Corp., Stratford, CT) reagent-grade iodine 100-mm glass cell with Teflon stoppers for absorption studies heating tape with controlling Variac 50-mm cell for emission studies vacuum system, preferably with a diffusion pump and cold trap, for pumping down emission cell. 

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