Pressurized water reactor typical operating conditions

Table 49-1 Typical Design Exposure Conditions of Coatings for Normal Operation of Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs)...

In the 1970s, there was a series of unanticipated operational events that occurred in commercial operating pressurized water reactors (PWRs) in the USA (NRC, 2012).These events resulted in pressures and temperatures in the RPV that were outside the P-TUmits specified for normal operation. The conditions associated with these unanticipated events could be placed into two categories. Rrst, there were approximately 30 transient events where the pressure in the RPV exceeded the allowable pressure at relatively low temperature. These events were isothermal pressure transients that generally occurred at temperatures below approximately 93 C (200°F) during reactor start-up. In many instances, the transient pressures were several times the allowable pressure. Typically, the transients occurred while the reactor coolant system was filled with water and were a result of operators failing to follow appropriate procedures to control and prevent... 

Fig. A 1.11 shows typical operating conditions of aU water" -cooled reactors on the pressure—temperature diagram. And Table A1.3 lists major parameters of Russian power reactors and NPPs because Russia has quite a wide range of various types of operating nuclear power reactors.

The reactions with ruthenium carbonyl catalysts were carried out in pressurized stainless steel reactors glass liners had little effect on the activity. When trimethylamine is used as base, Ru3(CO) 2> H Ru4(CO) 2 an< H2Ru4(CO)i3 lead to nearly identical activities if the rate is normalized to the solution concentration of ruthenium. These results suggest that the same active species is formed under operating conditions from each of these catalyst precursors. The ambient pressure infrared spectrum of a typical catalyst solution (prepared from Ru3(CO)i2> trimethylamine, water, and tetrahydrofuran and sampled from the reactor) is relatively simple (vq q 2080(w), 2020(s), 1997(s), 1965(sh) and 1958(m) cm ). However, the spectrum depends on the concentration of ruthenium in solution. The use of Na2C(>3 as base leads to comparable spectra. 

The solvent-refined coal (SRC) reactor is normally operated at 850 °F and 2,000 lbf in 2 pressure. Creosote oil is used as solvent In a typical operation, coal particles of approximately 74 jum diameter with a solvent/coal ratio of 2 are used. The slurry is passed through a 2.5-in-i.d., 4-ft-tall reactor. Assuming that coal specific gravity = 1.35, oil specific gravity = 0.9, surface tension of oil under reaction conditions = 5 dyne cm" , viscosity of oil under reaction conditions = 0.7 cP, static slurry height in bed =10 cm, surface tension of liquid (surface tension of water (ow) = 72 dyne cm -... 

The primary coolant circuit of a PWR is shown in schematic form in Fig. 36. In this particular circuit, there are four loops between the reactor and the steam generators. The pressurizer is also shown, which maintains the pressure in the primary loop at a sufficiently high value (typically 150 bar) such that sustained boiling does not occur and maintains the desired concentration of hydrogen in the coolant. The reactor heat removal system (RHRS) and the reactor water cleanup system are not shown. The general operating conditions in a PWR primary loop are summarized in Table 2. 

The commercial Co-Mo catalysts operate in the temperature range 250-350 °C and at pressures from atm to 40 bar. The typical process conditions for a Texaco partial oxidation process that generate syngas from heavy oil which use sour Co-Mo WGS catalyst are shown in Table 4.3. Three Co-Mo catalysts beds are used. The syngas from partial oxidation reactor contains 0.25% of H2S. The inlet CO concentration of 46% is reduced to 1% at the exit of third bed. However, the Co-Mo catalyst converts H2S and CO into COS. Hence, COS hydrolysis has to be performed after the water-gas shift reaction. However, if we... 

The aqueous Kolbe-Schmitt synthesis with resorcinol needs about 2h to achieve a 50% yield of the product under typical batch conditions with reflux of the solvent water (100 °C) [42]. In a setup with a minitube reactor and microcooler for quenching the reaction, high-temperature conditions at high pressures can be easily realized. Operation up to 200 °C at pressures of 40-70 bar allows a reduction of the reaction time to about 1 min or below with maximum yields of 45%. Similar findings were made for the phloroglucinol-based Kolbe-Schmitt synthesis [43]. Here, decarboxylation is more pronounced at lower temperature, which decreases the yield so that the operating temperature window is smaller, which also shows the limits of the applicability of the novel process window. 

Oxidation of cumene to cumene hydroperoxide is usually achieved in three to four oxidizers in series, where the fractional conversion is about the same for each reactor. Fresh cumene and recycled cumene are fed to the first reactor. Air is bubbled in at the bottom of the reactor and leaves at the top of each reactor. The oxidizers are operated at low to moderate pressure. Due to the exothermic nature of the oxidation reaction, heat is generated and must be removed by external cooling. A portion of cumene reacts to form dimethylbenzyl alcohol and acetophenone. Methanol is formed in the acetophenone reaction and is further oxidized to formaldehyde and formic acid. A small amount of water is also formed by the various reactions. The selectivity of the oxidation reaction is a function of oxidation conditions temperature, conversion level, residence time, and oxygen partial pressure. Typical commercial yield of cumene hydroperoxide is about 95 mol % in the oxidizers. The reaction effluent is stripped off unreacted cumene which is then recycled as feedstock. Spent air from the oxidizers is treated to recover 99.99% of the cumene and other volatile organic compounds. 

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