MOX fuel

Other options for eliminating weapons-grade plutonium arc to seal it permanently in solid radioactive waste and dispose of it in waste repositories, and to use the plutonium to fuel fast neutron reactors (without reprocessing the plutonium into a MOX fuel). 

Alternative reactor types are possible for the VHTR. China s HTR-10 [35] and South Africa s pebble bed modular reactor (PBMR) [41] adopted major elements of pebble bed reactor design including fuel element from the past German experience. The fuel cycles might be thorium- or plutonium-based or potentially use mixed oxide (MOX) fuel. 

Mixed-oxide (MOX) fuel, 19 700 25 400 Mixed-phase ethylene hydration process, 10 538-539... 

Moving body viscometers, 21 737-739 Moving-hearth incinerators, 13 177 MOX fuel, 19 686 Moxifloxacin, 21 224, 228, 231 Moxifloxacin, 3 25, 29 Mozley multigravity separators (MGS),... 

The long-term consequences of a-decay will be He gas build-up, which may lead to grain boundary disintegration. Poinssot et al. (2002) have shown that the internal pressures generated over time in LWR fuels from He gas are insignificant however, the pressures that could be produced by mixed oxide (MOX) fuels may need to be considered. 

About two-thirds of the separated Pu are used in mixed oxide (MOX) fuel fabrication. 

After a peak at 2010, the amount of Pu stored is supposed to start decreasing due to the expected increase in MOX fuel fabrication and its usage in Light Water Reactors (LWRs). Obviously, the utilization of MOX fuel by LWRs would gradually reach a balance in which the fissile Pu in the LWR fuel is ca. 5% of the total fuels. Consequently, the utilization of U resources would not be drastically improved. The ultimate utilization will be attained in the Fast Breeder Reactor (FBR) fuel cycle, in which a conversion of fertile 238U to 239Pu overwhelms the consumption of the 239Pu. 

Although the PUREX process is regarded as a well-matured chemical technology in the nuclear industry, owing to its complex chemistry, high radiation field, evolution of the fuels to be processed (i.e., extended high burn-up and MOX fuel), safety and economical issues, and its principal position in establishing the nuclear fuel cycle, both fundamental and application studies have been continued. 

Kumar, Sh., Koganti, S.B. 2005. FBR MOX fuel reprocessing B Computer simulation of mixer settler experiments (reprocessing of 70%UO2 + 30%PuO2 Dounreay and KNK fuels) by indigenous computer code SIMPSEX. Proc. ISEC 2005, Beijing, China, September 19-23. 

After feed acidity adjustment, plutonium and neptunium are recovered in the NPEX process, with high yields and sufficiently low impurity levels to make them suitable for MOX fuel fabrication. 

However, several optional processes are also envisaged to address GEN IV concerns (i) selective recovery of Pu to produce MOX fuels, (ii) separation of TRU from lanthanides to prepare targets for the transmutation of TRU in Accelerator-driven... 

Distribution ratios and transport were carried out on real HAW arising from dissolution of a mixed oxide of uranium and plutonium (MOX) fuel (burnup 34,650 MW d/tU), where uranium and plutonium have been previously extracted by TBP.86 The experiments were performed in the CARMEN hot cell of CEA Fontenay aux Roses with two dialkoxy-calix[4]arene-crown-6 derivatives (diisopropoxy and dini-trophenyl-octyloxy). High cesium distribution ratios were obtained (higher than 50) by contacting the HAW solution with diisopropoxy calix[4]arene-crown-6 (0.1 M in NPHE). Moreover, the high selectivity observed with the simulated waste was confirmed for most of the elements and radionuclides (actinides or fission products Eu, Sb, Ce, Mo, Zr, and Nd). The residual concentration or activity of elements, other than cesium, was less than 1% in the stripping solution, except for iron (2%) and ruthenium (8%) the extraction of these two cations, probably under a complexed... 

HEU) or mixed oxide (MOX) fuel containing oxides of uranium and plutonium in commercial nuclear power reactors, in order to dispose of nuclear weapons materials. Other theoretical reactor concepts are also being investigated for disposal of actinides. 

Yb-169 Used during brain scans U-235 Fuel for most nuclear reactors Pu-239 Used in nuclear weapons, fast breeder reactors, and MOX fuel reactors Am-241 Used in smoke detectors... 

IAEA projections of plutonium inventories show that the rate of separation of civil plutonium and its rate of use will fall into balance in a few years. This is due to an enhanced capacity of MOX fuel production which will amount to 360 tonnes of heavy metal per year in 2000. Beyond this period, the inventory is expected to decrease modestly and level off at around 130 tonnes. Despite the efforts to reduce the current inventories of separated civil plutonium, the worldwide inventories still remain at a substantial level, as shown in Fig. 7.3. 

Presently, plutonium is used in light-water reactors as MOX fuel and also in small amounts for the development of fast-breeder reactors. Currently 22 power reactors in five countries (France, Germany, Switzerland, Belgium, and Japan) are loaded with MOX fuel and this number is expected to rise to between 36 and 48 by 2000. The use of MOX reduces the inventory of separated plutonium and is regarded as an interim measure before plutonium s possible full-scale use in fast reactors later in the next century. It is known that multiple recycling in light-water reactors degrades plutonium, which in turn limits the number of times it can be recycled to two or three. Such... 

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