Irradiation-Driven Systems

Scheme 22 Thermal and UV irradiation-driven C-H activation of ethylene by the 3-(piperidinemethyl)pyrazolate Ir2 system...

Although some of the long-lived fission products have thermal neutron capture cross sections suitable for transmutation in reasonable irradiation times, others do not and would require reactors with very high neutron fluxes to reduce inventories significantly. As a result, dedicated reactors with large thermal fluxes and/or dedicated accelerator-driven systems... 

Oxide, metal alloy and inen matrix fuels and targets containing MA and Tc are fabricated, at a laboratory scale, and scheduled for irradiation. Concepts of nitride and molten salt fuels have been proposed for the advanced transmutation systems, e.g. actinide burners and accelerator driven systems. 

With U directly as initial fissile material for example, assuming that this U can be produced in fertile blankets of other reactors (SFR, etc.) or by irradiating Th in an accelerator-driven system. Once an initial park of MSFRs based on the Th- U cycle is launched,... 

The progress achieved in the detailed understanding of photophysical and photochemical processes that may be induced by light-irradiation in particular spin crossover systems has driven research efforts towards the development of materials that may be used for various technological applications. Only relatively recently, reports have appeared exploring this field for Fe(III) spin crossover materials. 

Another photochemically driven proton transfer occurs in the system 46. This molecule on sublimation at low temperatures crystallizes in form 46a having infinite chains of intermolecular hydrogen bonds connecting zwitterionic molecules. Its fluorescence at such temperatures is essentially that of the acridinium ion. However, on prolonged UV irradiation, conversion to 46b occurs and the... 

Fusion Systems (Gaithersburg, MD) at one time offered 240 W/cm microwave-driven excimer lamps within its VIP (Versatile Irradiance Platform) series. They were among the most powerful sources of UV radiant power,i available... 

Bimolecular reactions of the ion-radical pair can also effectively compete with the back electron transfer if either component undergoes a rapid reaction with an additive that is present during the ET activation. In NO+/arene systems, the introduction of oxygen rapidly oxidizes even small amounts of nitric oxide to compete with back ET and thus successfully effect aromatic nitration [60]. In a related example, the CT complex of hexamethylbenzene and maleic anhydride reaches a photostationary state with no productive reaction. However, if irradiation is carried out in the presence of an acid, the anion radical in the resulting contact ion-radical pair is readily protonated, and the redox equilibrium is driven toward coupling (in competition with the back ET) to yield the photoadduct [59], i.e. ... 

Another approach to the production of UV photons includes the development of electrode-less discharge lamps driven by microwave excitation (e.g. Fassler et al., 2001, Ametepe et al., 1999, He et al., 1998). This type of lamp is shown in Fig. 4-17. In this case, the excitation of mercury vapor within the discharge gap is achieved by coupling in the energy with a water-cooled high-frequency spool. This concept may be a very convenient tool for microwave photochemistry experiments by simultaneous combination of microwave and VUV/UV irradiation of aqueous systems (c.f Klan et al., 2001, 1999). 

---