The flux and the spectrum of reactor antineutrinos depend not only on the current reactor state, which is specified by the power level and the isotope composition of the nuclear fuel used, but also on the preceding evolution of the fuel. The spectrum of antineutrinos produced in the beta decay of fission products and other radioactive nuclei accumulated in the reactor core begin to evolve towar...

So far 22 criticality accidents have been reported (McLaughlin et al., 2000) including JCO accident in Japan. All cases took place with fuel solution or slurry except one case of metal fuel. It was not clear that what was actually happening during those criticality accidents except the JCO accident, for which a fission power profile was reproduced from a gammaray monitoring data (Tonoike et al....

One of the techniques of minor actinides transmutation is to recycle these nuclides into fission reactors. Two concepts of a minor actinides burner reactor with very hard neutron energy spectrum as well as very high neutronjlux me discussed. The fuel cycle facilities for these burner reactors am assessed to discuss the technical feasibili~ of these reactors. Transmutation of minor actinide in b...

This work presents experimental results on the distribution of irradiated reactor uranium from fallout after the accident at Chernobyl Nuclear Power Plant (NPP) in comparison to natural uranium distribution in different soil types. Oxidation processes and vertical migration of irradiated uranium in soils typical of the 30 km relocation area around Chernobyl NPP were studied using 236U as the tr...

Geomagnetic field reversals and changes in intensity are understandable from an energy standpoint as natural consequences of intermittent and/or variable nuclear fission chain reactions deep within the Earth. Moreover, deep-Earth production of helium, having (3)He/(4)He ratios within the range observed from deep-mantle sources, is demonstrated to be a consequence of nuclear fission. Numerical s...

Nuclear fission is capable of meeting global needs for carbon-free energy for millennia. However, the siting and implementation of waste repositories for spent fuel is becoming increasingly problematic from a financial and political perspective. We have performed initial studies of a novel concept for the permanent disposal of longlived fission waste, where “permanent” is defined as being on th...

In reactor calculations, a detailed 3-D power density distribution is required for core optimization studies and safety analyses. The general Monte Carlo based neutral particle transport tool, MCNP [1], has the capability to obtain detailed power density distribution in a reactor through its criticality calculation mode (KCODE mode). However, there is no standard tally type in MCNP that is able...

The technical principles and practices of the civil nuclear industry are described with particular reference to fission and its products, natural and artificial radioactivity elements principally concerned and their relationships, main types of reactor, safety issues, the fuel cycle, waste management, issues related to weapon proliferation, environmental considerations and possible future devel...

In Japan, since plutonium is to be used as a nuclear fuel material under the nuclear energy policy, the objective of partitioning and transmutation (P&T) is oriented to removal and transmutation of mainly MA and long-lived fission products. Under the OMEGA (option making of extra gain from actinides and fission products transmutation) programme, on the basis of the double-strata fuel cycle conc...