Since its discovery 75 years ago fission has been at the forefront of nuclear science and engineering research. Although the fission process is being used worldwide to generate safe reliable power, there are several aspects of the fission process which are still not well known. One such parameter of the fission process is the prompt fission neutron spectrum (PFNS). Although the average number o...

Compensating errors between several nuclear data observables in a library can adversely impact application simulations. The EUCLID project (Experiments Underpinned by Computational Learning for Improvements Nuclear Data) set out to first identify where compensating could be hiding our libraries, and then design validation experiments optimized reduce chosen of data. Adjustment will performed as...

One of the most significant remaining challenges associated with expanded implementation of burnup credit in the United States is the validation of depletion and criticality calculations used in the safety evaluation—in particular, the availability and use of applicable measured data to support validation, especially for fission products. Applicants and regulatory reviewers have been constraine...

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....

Criticality concerns, decay heat management and radioactive waste handling are perceived as the primary, unsatisfactorily resolved technological problems of nuclear reactors. They all originate from very specific features of a fission phenomenon: self-sustained chain reaction in fissile materials, very strong radioactivity of fission products and very long half-life of some of the radioactive f...

Monitoring of transuranic actinides (TRU–includes neptunium, plutonium, americium, and curium) during the separation of used nuclear fuel has been identified as a critical research area in the U.S. Advanced Fuel Cycle Research and Development program (AFC R&D). Recycling of used fuel by chemically separating it into uranium, fission products, and TRU would be the first step in this new fuel cyc...

We present an approach to uncertainty quantification for nuclear applications, which combines the covariance evaluation of differential cross-sections data and the error propagation from matching a criticality experiment using a neutron-transport calculation. We have studied the reduction in uncertainty of Pu fission cross sections by using a one-dimensional neutron-transport calculation with t...

The fission rate during JCO criticality accident is estimated from fission-product (FP) radioactivities in a uranium solution sample taken from the preparation basin 20 days after the accident. The FP radioactivity data are taken from a report by JAERI released in the Accident Investigation Committee. The total fission number is found quite dependent on the FP radioactivities and estimated to b...