An estimated 3.5±0.7×10(15) Bq of (137)Cs is thought to have been discharged into the ocean following the melt down at Fukushima Dai-ichi Nuclear Power Plant (F1NPP). While efforts have been made to monitor seafloor radiation levels, the sampling techniques used cannot capture the continuous distribution of radionuclides. In this work, we apply in situ measurement techniques using a towed gamma ray spectrometer to map the continuous distribution of (137)Cs on the seafloor within 20 km of the F1NPP. The results reveal the existence of local (137)Cs anomalies, with levels of (137)Cs an order of magnitude higher than the surrounding seafloors. The sizes of the anomalies mapped in this work range from a few meters to a few hundreds of meters in length, and it is demonstrated that the distribution of these anomalies is strongly influenced by meter scale features of the terrain.
An overview is presented of recent nuclear data evaluations performed for the JENDL high-energy (JENDL-HE) file, in which neutron and proton cross sections for energies up to 3 GeV are included for the whole 132 nuclides. The current version of the JENDL-HE file consists of neutron total cross sections, nucleon elastic scattering cross sections and angular distributions, nonelastic cross sections, production cross sections and double-differential cross sections of secondary light particles (n, p, d, t, 3 He, α, and π) and gamma-rays, isotope production cross sections, and fission cross sections in the ENDF6 format. The present evaluations are performed on the basis of experimental data and theoretical model calculations. For the cross section calculations, we have constructed a hybrid calculation code system with some available nuclear model codes and systematics-based codes, such as ECIS96, OPTMAN, GNASH, JQMD, JAM, TOTELA, FISCAL, and so on. The evaluated cross sections are compared with available experimental data and the other evaluations. Future plans of our JENDL-HE project are discussed along with prospective needs for high-energy cross section data.
The JENDL Dosimetry File based on Japanese Evaluated Nuclear Data Library Version 3 (JENDL-3) was compiled, and integral tests of the dosimetry cross section data were performed by the Dosimetry Integral Test Working Group of the Japanese Nuclear Data Committee. Sixty-one reaction cross sections and their covariance data are stored in the JENDL Dosimetry File. The cross sections were mainly taken from JENDL-3 and the covariances from IRDF-85. The data are given in the neutron energy region below 20 MeV in point and group files in the ENDF/B-V format.
In order to confirm reliability of data in the JENDL Dosimetry File, several integral tests were carried out: comparison with average cross sections measured in fission neutron and fast reactor spectra, DT, and Li(d,n) neutron fields. As a result, it has been found that the calculated and the measured average cross sections are in general agreement with each other. However, some of the dosimetry cross sections still showed marked discrepancies between the measured and the calculated data. These discrepant cross sections have been reevaluated and the integral tests have been repeated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.