Physics of Americium Transmutation

Wallenius, Janne

doi:10.5516/net.01.2012.505

Cited by 20 publications

(12 citation statements)

References 9 publications

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“…7). Those are in agreement with further investigations of those reactivity effects which are presented in different works [2,12,17,20,22,28,29,31].…”

Section: Discussionsupporting

confidence: 80%

“…In this case additional differences between delayed and prompt neutrons spectra are crucial. Effective delayed neutron fraction is lower than  because in typical fast spectrum delayed neutrons have lower probability to cause fi ssion than prompt neutrons for even nuclides [28]. Moreover, minor actinides (mainly americium) have few times higher capture cross-sections for average energies of delayed neutrons in comparison to 238 92 U [21].…”

Section: Discussionmentioning

confidence: 99%

“…On the contrary, the main plutonium isotopes present in the analyzed fuel: (Table 3) 239 94 Pu generates 2.93 neutrons and  equals 215 pcm, 240 94 Pu generates 3.07 neutrons and  equals 310 pcm for the same fast spectrum [2]. The most abundant minor actinide -241 95 Am in case of 1 MeV incident neutron produces 3.37 neutrons and  equals about 130 pcm [28].…”

Section: Discussionmentioning

confidence: 99%

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Minor actinides impact on basic safety parameters of medium-sized sodium-cooled fast reactor

Darnowski

Uzunow

2015

Nukleonika

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Abstract. An analysis of the infl uence of addition of minor actinides (MA) to the fast reactor fuel on the most important safety characteristics was performed. A special emphasis was given to the total control rods worth in order to describe qualitatively and quantitatively its change with MA content. All computations were performed with a homogeneous assembly model of modifi ed BN-600 sodium-cooled fast reactor core with 0, 3 and 6% of MA. A model was prepared for the Monte Carlo neutron transport code MCNP5 for fresh fuel in the beginning-of--life (BOL) state. Additionally, some other parameters, such as Doppler constant, sodium void reactivity, delayed neutron fraction, neutron fl uxes and neutron spectra distribution, were computed and their change with MA content was investigated. Study indicates that the total control rods worth (CRW) decreases with increasing MA inventory in the fuel and confi rms that the addition of MA has a negative effect on the delayed neutron fraction.

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“…7). Those are in agreement with further investigations of those reactivity effects which are presented in different works [2,12,17,20,22,28,29,31].…”

Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Minor actinides impact on basic safety parameters of medium-sized sodium-cooled fast reactor

Darnowski

Uzunow

2015

Nukleonika

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“…However, transmuting MAs in fast reactors has significant effects on the safety performance of reactor cores . The absence of uranium leads to both very low delayed neutron fraction and small Doppler reactivity coefficient.…”

Section: Introductionmentioning

confidence: 99%

Reactor core transient analysis of an innovative high-level nuclear waste transmuter with metal fuel

Zheng

Cao

et al. 2017

Int. J. Energy Res.

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Summary For the sustainable development of nuclear energy, reducing high‐level nuclear wastes in spent fuels discharged from commercial nuclear power plants is very important. Partitioning and transmutation of minor actinides from these spent fuels are critical for the effective disposal of high‐level wastes. However, transmutation in current operational reactors is not efficient and brings some safety problems. Therefore, a dedicated accelerator‐driven subcritical transmuter named highly efficient industrial transmuter (HEIT) was newly proposed to solve the problems. This system utilizes the uranium‐free metallic dispersion fuel and is of high power density. This paper focuses on the transient analysis of HEIT to prove that it is feasible for the future nuclear industry. Temperatures, cladding stresses, and cumulative creep damage fractions are analyzed. Furthermore, the burnup dependence is also investigated. Three typical transients including the unprotected loss of flow, the beam overpower (BOP), and the unprotected transient overpower are evaluated. Numerical results conclude that in the reactivity insertion transient and the BOP transient, this new system exhibits excellently in safety. However, the shut‐down system is required in flow loss case which lasts more than half an hour. The safety margin changes with core depletion. For unprotected loss of flow, the end of lifetime case is the most important one to care. While for BOP and unprotected transient overpower, both the beginning and end of lifetime should be accommodated. The conclusions will be useful in the future design of HEIT and similar systems. Copyright © 2017 John Wiley & Sons, Ltd.

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“…For instance, it was shown in [5,6] that reducing core power was necessary to keep safety margins acceptable when homogeneously loading a core with americium. A detailed description of the impact of americium loading in a core can be found in Wallenius [7]. The entire fuel cycle is also "polluted" with minor actinides to some extent.…”

Section: Introductionmentioning

confidence: 99%

Analysis and optimization of minor actinides transmutation blankets with regards to neutron and gamma sources

Kooyman

Buiron

Rimpault

2017

EPJ Nuclear Sci. Technol.

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Abstract. Heterogeneous loading of minor actinides in radial blankets is a potential solution to implement minor actinides transmutation in fast reactors. However, to compensate for the lower flux level experienced by the blankets, the fraction of minor actinides to be loaded in the blankets must be increased to maintain acceptable performances. This severely increases the decay heat and neutron source of the blanket assemblies, both before and after irradiation, by more than an order of magnitude in the case of neutron source for instance. We propose here to implement an optimization methodology of the blankets design with regards to various parameters such as the local spectrum or the mass to be loaded, with the objective of minimizing the final neutron source of the spent assembly while maximizing the transmutation performances of the blankets. In a first stage, an analysis of the various contributors to long-and short-term neutron and gamma source is carried out whereas in a second stage, relevant estimators are designed for use in the effective optimization process, which is done in the last step. A comparison with core calculations is finally done for completeness and validation purposes. It is found that the use of a moderated spectrum in the blankets can be beneficial in terms of final neutron and gamma source without impacting minor actinides transmutation performances compared to more energetic spectrum that could be achieved using metallic fuel for instance. It is also confirmed that, if possible, the use of hydrides as moderating material in the blankets is a promising option to limit the total minor actinides inventory in the fuel cycle. If not, it appears that focus should be put upon an increased residence time for the blankets rather than an increase in the acceptable neutron source for handling and reprocessing.

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Physics of Americium Transmutation

Cited by 20 publications

References 9 publications

Minor actinides impact on basic safety parameters of medium-sized sodium-cooled fast reactor

Minor actinides impact on basic safety parameters of medium-sized sodium-cooled fast reactor

Reactor core transient analysis of an innovative high-level nuclear waste transmuter with metal fuel

Analysis and optimization of minor actinides transmutation blankets with regards to neutron and gamma sources

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