Plutonium composition

OOIS Ci Pu is released annually from a reprocessing plant. What will be the corresponding release of Pu and Pu for typical isotopic plutonium composition of LWR fuel ... 

Suppression of the first row of radial blankets of the present core. Beginning with a core that produces 36 kg/TWh in total plutonium, this stage reduces production to 27 kg/TV fti. On the planned cycle up to the complete burning of the present core, in other words about on year of operation, total plutonium production will be reduced by 50 kg. Evolution of the plutonium composition will be measured after unloading. 

Table 3 equilibrium plutonium composition in the multi-recycling process in a CAPRA... 

Two plutonium compositions were used, as listed in Fig. 1, vdiich also shows the designs of the coextruded aluminum fuel assemblies. Hie experimental lattices consisted of 19 of these fuel assemblies in hexagonal arrays at 12.12- or 14.00-in. pitches. To provide an easily calculated radial boundary, the fuel lattices were extended for two additional rings with nonfissioning iron-lithium assemblies having very nearly the same absorption cross section as the fuel. 

Figure 1 shows for a given Pu wt% the minimum Pu-to- Pu weight ratio required to make the maximum reactivity of the DBF rods, with such plutonium composition, equal to the maximum reactivity of the DBF rods... 

The plutonium composition in reactor core is unattractive for weapon purposes ... 

Reactivity changes and plutonium isotopic compositions were first examined for a commercial pressurized water reactor (PWR) operating on a low enrichment (3.2 wt% equilibrium fuel cycle. The results aided in understanding the significance of a number of approximations made in this assessment. The results also provided some perspective on the plutonium composition in spent conunercial reactor fuels. 

Table 4. Isotopic Composition of Plutonium from Thermal Power Reactors — ...

Oxalates. Stable oxalates of Pu(III), Pu(IV), and Pu(VI) are known. However, only the Pu(III) and Pu(IV) oxalates are technologically important (30,147). Brilliant green plutonium(III) oxalate [56609-10-0] precipitates from nitric acid solutions containing Pu(III) ions upon addition of oxaUc acid or sodium oxalate. The composition of the precipitate isPu2(C20 2 10H2O. A homogeneous oxalate precipitation by hydrolysis of diethyl oxalate at... 

J. A. Leary, Studies on the Preparation, Properties, and Composition of Plutonium Peroxide, LA-1913, Los Alamos Scientific Laboratory, N.M., 1955. 

To review the available evidence, the plutonium in both compounds is trivalent, the compounds have coordinated or bonded ethylenic groups, and the empirical formulae are PuIjC H THF (the reaction product) and PuIgCgH (the pyrolytic product). Formulae that are consistant with this evidence are PuI3(CH2=CH2) 4THF for the reaction product, and PuI2(CH CH2) for the pyrolytic product. The evidence is only sufficient to propose these compositions, and until corroborative measurements can be made, these formulae should be considered tentative. 

Although the phase which appears to be very stable for plutonium has not been observed in other An02 S03 H20 systems, phases of identical composition have been observed for Zr, Hf and Ce. The crystal structure of the zirconium compound Zr2(0H)2-(SOO 3 (H20) i,, is well known 05). One very interesting feature of the M02 S03 H20 systems for Zr, Hf and Co is that there are a large number of phases which have been observed. Some of these correspond to phases which are known for Th, U and Np. For zirconium, a series of basic sulfates is known to include Zr2(0H)2-(SOi,) 3 (H20)i, and two modifications of Zr(0H)2S0i, as the major constituents (5). Other basic sulfates such as Zr(OH)2S0if,H20,... 

The only crystalline phase which has been isolated has the formula Pu2(OH)2(SO )3(HaO). The appearance of this phase is quite remarkable because under similar conditions the other actinides which have been examined form phases of different composition (M(OH)2SOit, M=Th,U,Np). Thus, plutonium apparently lies at that point in the actinide series where the actinide contraction influences the chemistry such that elements in identical oxidation states will behave differently. The chemistry of plutonium in this system resembles that of zirconium and hafnium more than that of the lighter tetravalent actinides. Structural studies do reveal a common feature among the various hydroxysulfate compounds, however, i.e., the existence of double hydroxide bridges between metal atoms. This structural feature persists from zirconium through plutonium for compounds of stoichiometry M(OH)2SOit to M2 (OH) 2 (S0O 3 (H20) i,. Spectroscopic studies show similarities between Pu2 (OH) 2 (SOO 3 (H20) i, and the Pu(IV) polymer and suggest that common structural features may be present. 

It should be emphasized that a survey of the vapor pressure measurements of plutonium-bearing species above bivariant Pu02-x(s) revealed that in general these measurements suffer from a lack of knowledge of the composition of the condensed phase. 

Figure 2. Partial pressures of vapor species versus composition of the substoichiometric plutonium dioxide phase at 1970 K.

Measurements of oxygen potentials and vapor pressure of plutonium-bearing species above a wide range of Pu-0 compositions, including the difficult region close to stoichiometric plutonia, should be made at high temperatures, particularly above 3000°C, for purpose of safety analysis. 

Vapor Pressures and Vapor Compositions in Equilibrium with Hypostoichiometric Plutonium Dioxide at High Temperatures... 

Vapor pressures and vapor compositions in equilibrium with a hypostoichiometric plutonium dioxide condensed phase have been calculated for the temperature range 1500 I H 4000 K. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen-potential model, which we extended from the solid into the liquid region to obtain the partial pressures of O2, 0, Pu, PuO and Pu02 as functions of temperature and of condensed phase composition. The calculated oxygen pressures increase rapidly as stoichiometry is approached. At least part of this increase is a consequence of the exclusion of Pu +... 

One of the most Important thermophysical properties of reactor fuel In reactor safety analysis Is vapor pressure, for which data are needed for temperatures above 3000 K. We have recently completed an analysis of the vapor pressure and vapor composition In equilibrium with the hypostolchiometric uranium dioxide condensed phase (1 ), and we present here a similar analysis for the plutonium/oxygen (Pu/0) system. 

An alternative way to view the oxygen enrichment of the vapor relative to the condensed phase Is to calculate the oxygen-to-plutonium ratio of the gas, R(gas), with Eq. (2). The value of R(gas) exceeds that of the condensed phase with which It Is In equilibrium by a large amount. Like the U/0 system, this oxygen enrichment of the vapor relative to the condensed phase Is Increasing with temperature. One Implication of these results Is that the condensed-phase and vapor-phase compositions will depend upon the extent of vaporization of a sample with overall composition given by 0/Pu = 2 - x. 

Green, D. W. Fink, J. K. Leibowitz, L. "Vapor Pressures- and Vapor Compositions in Equilibrium with Hypostoichiometric Uranium-Plutonium Dioxide at High Temperatures," presented at the 8th European Conference on Thermophysical Properties, Baden-Baden, September 27 - October 1, 1982 to be published in High Temperatures-High Pressures. 

Photodecomposition. A greyish-white film of solid material slowly formed along the bottom of the sample cell in PuF6 cells irradiated at 1064 nm. A similar film formed considerably faster in sample cells irradiated at 532 nm with the film forming on the entrance face of the cells as well as along the walls of the cell. Film formation was evident after less than a minute of irradiation at a laser fluence of 5 J/cm2 at 532 nm. The exact chemical composition of the film has not yet been determined. It is known that it contains plutonium and... 

Rain in equilibrium with atmospheric C02, but uncontaminated by industrial emissions, should have a pH of 5.7. However, atmospheric pollution from burning fossil fuels has resulted in acid rain of pH as low as 3.5 (24). If this condition continues for a long time, it may lead to a change in groundwater composition, which may considerably change the migration of plutonium in nature. 

Ground-Water Composition and Its Relationship to Plutonium Transport Processes... 

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