PRISM module

Monsanto s Prism permeators for gas separation also employ composite membranes. Polyamide coatings are not used for the composite membrane in the Prism module. The Prism membrane consists of a coating of silicone rubber applied from an organic solvent on a porous polysulfone substrate. The Prism membrane is another good example of a composite membrane where Structure Level IV is used to obtain good membrane properties (22). 

Salt makeup and chemistry control system. These are required and are assumed to be 75% of the cost of similar systems for a two-reactor S-PRISM module. 

Other structures. All other miscellaneous structures are assumed to have the same cost as those for a two-reactor S-PRISM module, except the control room and maintenance building, which have a 0.75 scaled cost. 

PRISM employs passive safety, digital instrumentation and control, and modular fabrication techniques to expedite plant construction [1-4]. PRISM has a rated thermal power of 840 MW and an electrical output of 311 MWe. Each PRISM module has an intermediate sodium loop that exchanges heat between the primary sodium coolant from the core with water/steam in a sodium-water steam generator (SG). The steam from the sodium-water SG feeds a conventional steam turbine. A diagram of the PRISM nuclear steam supply system (NSSS) is shown in Figure 6.2. 

A PRISM module, pictured in Figure 6.4, consists of the reactor vessel, reactor closure, containment vessel, internal structures, internal components, reactor module supports, and the reactor core. 

Air Products, with the Prism silicon-coated polysulfone membranes (issued from Monsanto). Air Products claims that the lifetime of the Prism modules can be more than 15 years. 

The heptane water and toluene water interfaces were simulated by the use of the DREIDING force field on the software of Cerius2 Dynamics and Minimizer modules (MSI, San Diego) [6]. The two-phase systems were constructed from 62 heptane molecules and 500 water molecules or 100 toluene molecules and 500 water molecules in a quadratic prism cell. Each bulk phase was optimized for 500 ps at 300 K under NET ensemble in advance. The periodic boundary conditions were applied along all three directions. The calculations of the two-phase system were run under NVT ensemble. The dimensions of the cells in the final calculations were 23.5 A x 22.6 Ax 52.4 A for the heptane-water system and 24.5 A x 24.3 A x 55.2 A for the toluene-water system. The timestep was 1 fs in all cases and the simulation almost reached equilibrium after 50 ps. The density vs. distance profile showed a clear interface with a thickness of ca. 10 A in both systems. The result in the heptane-water system is shown in Fig. 3. Interfacial adsorption of an extractant can be simulated by a similar procedure after the introduction of the extractant molecule at the position from where the dynamics will be started. 

The real structures of these phases are more complex. The coordination of the Ti atoms is always six, but the coordination polyhedron of sulfur atoms around the metal atoms is in turn modulated by the modulations of the Sr chains. The result of this is that some of the TiS, polyhedra vary between octahedra and a form some way between an octahedron and a trigonal prism. The vast majority of compositions give incommensurately modulated structures with enormous unit cells. As in the case of the other modulated phases, and the many more not mentioned, composition variation is accommodated without recourse to defects. ... 

Figure 5. SPR sensor based on ATR method and angular modulations (upper) and corresponding reflectivity calculated for two different refractive indices of sample (lower). Sensor configuration SF14 glass prism, 50 nm thick gold layer, sample, wavelength - 682 nm.

Fig. In prism-based SPR sensors with wavelength modulation and...

Fig. 6. Experimental arrangement for lifetime measurements by the phase-shift method, using laser excitation. The laser beam is amplitude-modulated by a Pockel cell with analysing Nicol prism and a small part of the beam is reflected by a beam splitter B into a water cell, causing Rayleigh scattering. This Rayleigh-scattered light and the fluorescence light from the absorption cell are both focused onto the multiplier cathode PMl, where the difference in their modulation phases is detected. (From Baumgartner, G., Demtroder, W., Stock, M., ref. 122)).

Here let us consider the structure of Bai+ Fe2S4 from the viewpoint of displacive modulated structures. As clearly seen from Fig. 2.38, Ba ions in the basic compound BaFe2S4 occupy regularly half of the face-capped tetragonal prisms (FCTP twelve coordinations) formed by S ions. The FCTP sites are at z = 0 and along the c-axis. The other sites for Ba ions are at z = j and I, where the Ba ions are eight coordinated by S ions (square anti-prism, SAP). The former sites are more stable than the latter ones, however, the occupation of all of the former sites seems to be impossible, due to the repulsive force between Ba ions. 

Experiments were performed using a titanium sapphire laser oscillator capable of producing pulses with bandwidths up to 80 nm FWHM. The output of the oscillator was evaluated to make sure there were no changes in the spectrum across the beam and was compressed with a double prism pair arrangement. The pulse shaper uses prisms as the dispersive elements, two cylindrical concave mirrors, and a spatial light modulator (CRI Inc. SLM-256), composed of two 128-pixel liquid crystal masks in series. The SLM was placed at the Fourier plane [5]. After compression and pulse shaping, 200 pJ pulses were used to interrogate the samples. 

As to the practical way of producing a suitable modulation, a series of proposals have been made. In practically all cases a modulator is introducted into the light beam, whereas the polarizing prisms are kept at rest. It appears that the general shape of the lower curve in Fig. 6.5 remains unchanged. More precise calculations can be carried out with the aid of a matrix calculus, as reviewed by Walker (216). 

Figure 19.6. Gas permeation equipment and performance, (a) Cutaway of a Monsanto Prism hollow fiber module for gas separation by permeation, (b) Flowsketch of a continuous column membrane gas separator, (c) Composition profiles of a mixture of C02 and Oz in a column 5 m long operated at total reflux [Thorman and Hwang in ( Turbak, Ed.), Synthetic Membranes II, American Chemical Society, Washington DC, 1981, pp. 259-279],...

---