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《Journal of Nuclear Science and Technology》2013,50(5):442-450
The present study focuses on the exploration of the effect of minor actinide (MA) addition into uranium oxide fuels of different enrichment (5% 235U and 20% 235U) as ways of increasing fraction of even-mass-number plutonium isotopes. Among plutonium isotopes, 238Pu, 240Pu and 242Pu have the characteristics of relatively high decay heat and spontaneous fission neutron rate that can improve proliferation-resistant properties of a plutonium composition. Two doping options were proposed, i.e. doping of all MA elements (Np, Am and Cm) and doping of only Np to observe their effect on plutonium proliferation-resistant properties. Pressurized water reactor geometry has been chosen for fuels irradiation environment where irradiation has been extended beyond critical to explore the subcritical system potential. Results indicate that a large amount of MA doping within subcritical operation highly improves the proliferation-resistant properties of the plutonium with high total plutonium production. Doping of 1% MA or Np into 5% 235U enriched uranium fuel appears possible for critical operation of the current commercial light water reactor with reasonable improvement in the plutonium proliferation-resistant properties. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(5):715-723
The present paper is prepared for the peaceful use of nuclear energy. Proliferation resistance of plutonium can be enhanced by increasing the decay heat of plutonium. For example, it can be enhanced by increasing the isotopic fraction of 238Pu, which has the largest decay heat among plutonium isotopes. In the present paper, the proliferation resistance of plutonium was evaluated based on decay heat with a physical assessment model. New criteria were proposed to evaluate the proliferation resistance based on isotopic compositions of plutonium from the viewpoint of decay heat. The present criteria were applied to evaluate the proliferation resistance of plutonium produced in typical Light Water Reactor and Fast Breeder Reactor based on an evaluation function “Attractiveness” as case studies. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(6):393-407
Fission product decay heat of 235U was calculated for short cooling-time on the basis of a preliminary version of a new decay data library recently completed by the Japanese Nuclear Data Committee. It was shown that a full adoption of recent publications of decay schemes to derive average energies of β- and γ-rays, ēβ, and ēγ, leads to a large underestimation of the γ-ray component of the decay heat and to an overestimation of the β-ray component. In order to remedy this, theoretical values of ēβ and ēγ were introduced for high Q-value decays, which were obtained with a gross theory of β-decay. It improved remarkably the agreement between calculation and experiment not only for the 235U decay heat but for 239Pu and 241Pu as well. It was concluded that a large part of decay schemes recently published for high Q-value nuclides are inappropriate to use in calculations of ēβ and ēγ, because they fail to reproduce the effect of β- strengths at high excitations, which makes ēβ small and ēγ large. The use of the gross theory introduces this effect correctly into the values of ēβ and ēγ and, hence, leads to a quite good prediction of both β- and γ-ray components of the decay heat. 相似文献
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Material attractiveness evaluations based on isotopic Plutonium barrier compositions have been investigated for evaluating intrinsic features of proliferation resistance such as decay heat (DH), spontaneous fission neutron (SFN), as well as attractiveness concepts of figure of merit (FOM) and “attractiveness” (ATTR) as a function of diluted fraction of even mass Plutonium to Pu-239 composition. The DH and SFN compositions increase significantly with increasing diluted fraction of even mass Plutonium, except for DH of Pu-242. It shows that diluted fraction of Pu-238 contributes most significantly to the DH ad SFN compositions at certain diluted fractions. Only diluted fraction of Pu-238 can reach a DH composition level of MOX fuel for small diluted fraction and an SFN level of MOX fuel can be reached by all diluted fractions of even mass Plutonium. It requires more than 80% of diluted Pu-238 fraction to achieve a low material attractiveness based on FOM1 formula and there is no available diluted fraction for Pu-240 and Pu-242 for reaching it. It is easier to reach a low material attractiveness by using FOM2 than that of FOM1 caused by additional contribution of the SFN component, as well as ATTR, which also considers both DH and SFN components. The material attractiveness of FOM2 and ATTR as a function of diluted even mass Plutonium fractions are shown in similar trend, which requires some diluted fraction depending on even mass Plutonium for achieving low material attractiveness of FOM 2 and practically unusable level of ATTR. 相似文献