Plutonium isotopic composition

C26.10 C1030-95 Standard Test Method for Determination of Plutonium Isotopic Composition by Gamma-Ray Spectrometry... 

Yamamoto M, Tsumura A, Katayama Y, Tsukatami T (1996) Plutonium isotopic composition in soil from the former semipalatinsk nuclear test site. Radiochim Acta 72 209-215 Burger M (2002) UNEP DU Post-Conflict Assessment 2001 Serbia/Montenegro. Report of the Swiss Team. Spiez Laboratory Report with 1 annex, Switzerland... 

This paper presents a set of isoreactivity curves, applicable only to mixed-oxide rods of a certain design, which permit the determination by simple inspection, rather than laborious calculation, of whether a different plutonium isotopic composition in the same rod design is more or less reactive than a base design of known reactivity for criticality safety purposes. In effect, the curves incorporate reactivity equivalency factors lor the three main isotopes of plutonium which are expected to vary as a function of recycling in reactors. An equation that predicts the percent reactivity increase of the mixed-oxide fuel rods where a certain percentage of the Pu isotope is replaced by Pu is also given. Criticality safety limits for new plutonium isotopic composition of fuel rods of the same design, therefore, may be determined more rapidly. 

The closeness of the curves shown in Fig. 1 suggests that a single isoreactivity curve could be conservatively applied to the DBF rods. This single isoreactivity curve is applicable only to the DBF rods with FuOb concentrations not exceeding 8 wt%, and for maximum content of 8Swt%. Mixed-oxide rods, similar in design to the DBF rods, whose plutonium isotopic composition can be represented by a point that falls below the Isoreactivity curve, are less reactive than the base system, and the criticality limits established for the base system are acceptable for the new rods. 

Sampson, T.E. (1991). Plutonium isotopic composition by gamma-ray spectroscopy, in Passive Nondestructive Assay... 

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. 

The calculated plutonium isotopic compositions are shown in Figure A-2. The 2 0pu isotopic content reaches 20% of total plutonium at an exposure of about 18 GWD/MT. The parasitic absorber (2 Pu plus Pu) content reaches 20% at a slightly lower exposure of about 16 GWD/ MT. Although these values can be considered representative, the plutonium content is dependent on the initial enrichment and the particular fuel management schemes employed. Current LWR operations employ initial enrichments in excess of 4% to achieve exposures in excess... 

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

Table 2.1 lists specific radionuclides that may be present in nuclear fuel rods or industrial sources used to construct a dirty bomb. It also lists the radiological half-lives of each radionuclide, whether they are present in fresh or spent fuel rods, and their potential industrial applications. Note that the actual suites of isotopes for given fuel rods will vary depending on the origin and composition of the original fuel mixture. The uranium and plutonium isotopes found in fuel rods may also be found... 

The relatively long-lived isotopes of Pu suitable for chemistry and metallurgy are those of masses 238, 239, 240, 241, 242, and 244. Plutonium formed in nuclear reactors occurs as a mixture of isotopes. A typical isotopic composition of Pu in spent fuel containing 10.4 kg of Pu/ton of fuel is given in Table VIII. 

Typical Isotopic Composition op Plutonium in Spent Reactor Fuel ... 

Meanwhile, work was being carried out to determine the parent of the supposed fission xenon component. In 1971, Calvin Alexander, working at Berkeley, measured the isotopic composition of a sample of plutonium that had been produced by a nuclear reactor. The sample was heated to release all trapped gases and then left on a shelf for 23 months to allow pure plutonium fission xenon to accumulate. The resulting precise composition of plutonium fission xenon eliminated plutonium as the parent of CCFXe. Another hypothesis, championed by Edward Anders of the University of Chicago, was that the CCFXe had been produced by fission of a super-heavy element. Nuclear physicists had presented theoretical... 

Amselfelder red wine from Kosovo has been investigated with respect to uranium and plutonium content using ICP-SFMS (Element). The microconcentric nebulizer Aridus (Cetac Technologies) was applied for solution introduction into the ICP source. In different red wine samples, uranium with a natural isotopic composition was found at a concentration of 0.145 0.011 Jigl-1, which corresponds to the normal uranium background concentration. Plutonium was not detected at a detection limit of 10-5p,gl-1.36... 

Popplewell, D.S., Ham, G.J., McCarthy, W. Morgan, M. (1989) Isotopic composition of plutonium in human tissue samples determined by mass spectrometry. Radiation Protection Dosimetry, 26, 313-16. 

Prior to beginning actual plant processing, it was necessary to flush all tanks and pipes extensively to avoid contamination of the plutonium and the americium with plutonium of a different isotopic composition or with fission products or other impurities. Processing began only after analyses of the flush solutions confirmed the product contamination would be acceptably low. 

Figure 7 The relationship between the xenon isotope compositions of the atmosphere, initial atmosphere, and the upper mantle as sampled by MORE. The line connecting the initial atmosphere (fractionated U-Xe) and the present atmosphere has a slope equal to the ratio of plutonium-derived Xe to radiogenic Xe ( Xe/ Xe) in the atmosphere. Any xenon that remained in the solid reservoir from where this was degassed must have a greater value for this ratio and so he in the shaded region (Ozima et al, 1985). While measured MORBs do so, upper-mantle compositions that have been corrected for U-derived Xe (based on MORE data of Kunz et al, 1998 and on CO2 weU gas data of Phinney et al, 1978) do not, indicating that upper-mantle xenon is not the residual left from atmosphere degassing.

Figure 8 The xenon isotope compositions of U-Xe and solar wind xenon, both nonfractionated and fractionated to match the light xenon isotopes, are compared to the value of the atmosphere. It is clear that fractionated solar wind xenon cannot serve as the non-radiogenic composition of the atmosphere since it has a higher Xe/ °Xe ratio. In order for the upper mantle to have the same Xe/ Xe ratio as the atmosphere, the nonradiogenic composition of the atmosphere must lie on the dotted lines, implying that there is very little plutonium-derived Xe. This is contrary to the inferred Pu budget of the Earth.

Large area portable detector for the isotopic analysis of weak plutonium and other samples. Measurement of the isotopic composition of weak plutonium samples. 

Aqueous Process. In 1967-68, a hot reprocessing test had been conducted using the spent fuel (ca. 600 MWD/T) from JRR-3 (Japan Research Reactor-3) (6). About 200 g of purified plutonium was recovered by a modified PUREX process from aluminum-claded uranium fuels of natural isotopic composition. 

For a given mass and isotopic composition of plutonium and contaminant concentration, neutron production rate and allowable concentration of a given contaminant can be estimated from data in Tables 8.13 and 8.14. Estimates for Pu containing 1000 ppm Pu and for containing 100 ppm are given in Table 8.15. By comparison, plutonium undergoing... 

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