Paleoclimatic controls on natural tracer profiles in biogenic sedimentary formations of the Horonobe area, Japan

Arthur, R.*; Sasamoto, Hiroshi; Alt-Epping, P.*; Tachi, Yukio

Applied Geochemistry, 155, p.105707_1 - 105707_8, 2023/08

https://doi.org/10.1016/j.apgeochem.2023.105707

The experience gained in modeling the evolution, from past to present, of natural tracer profiles in geologic media can help support safety assessment of disposal concepts for radioactive wastes in deep geologic repository. Solute-transport models were developed in the present study using a forward modeling approach constrained by boundary conditions inferred from the paleo-hydrogeological evolution of the Horonobe area in Hokkaido, Japan. Apparent differences in transport behavior at the two boreholes location considered in this study, which were situated only about 1 km apart, appear to have resulted from relatively small differences in accessible porosity and hydraulic conductivity, which in turn may have been controlled by local differences in fracture density and fracture connectivity.

Design of beam optics in the proton beam transport line from synchrotron to spallation neutron target

Meigo, Shinichiro; Noda, Fumiaki*; Fujimori, Hiroshi*; Ikeda, Yujiro

Proceedings of ICANS-XVI, Volume 3, p.967 - 976, 2003/07

In J-PARC project, spallation target is irradiated by 3 GeV proton beam of 1 MW. Due to hands on maintenance for the proton beam lines, loss of proton beam is limited less than 1 W/m. Since it is difficult to predict the phase space distribution of the proton beam, we decided that the beam line have to be larger acceptance for 324 mrad, which is determined by the collimator located in the synchrotron. Distortion of proton beam is caused by the by the instability of angle at the extraction of 3-GeV synchrotron, miss alignment of the magnet, and un-uniformity of the magnet field. In this study, the distortion is calculated. In order to fit the conditions, the stability of extraction angles should be kept smaller than 0.2 mrad. As for the magnetic field, it is found that the uniformity should be kept better 5x10 and 2x10 for bending and quadruple magnets, respectively. It is also found the error of alignments should be limited smaller than 1.0 mm and 1.0 mrad.

An Adjusted Cross Section Library for DFBR

Peter, J. Collins

PNC TN9410 97-034, 35 Pages, 1997/04

PNC-TN9410-97-034.pdf:1.07MB

While in the Reactor Physics Research Section of the Advanced Technology Division at OEC, I participated in the project to construct a data library for the demonstration fast breeder reactor (DFBR). This library would be produced using a combination of evaluated differential cross sections together with integral experimental data for fast reactors, so as to assure sufficiently accurate calculations for the DFBR designs. I had much experience of the design and use of experiments for the large-size cores at ZPPR under the title JUPITER which was performed under the USDOE/PNC joint agreement. My contribution here was mainly in extension of the experimental database to include the very-hard spectrum fast criticals from the Los Alamos National Laboratory (LANL). The data for these cores are described. Our work at ANLW with the GMADJ code, which is similar in effect to the ABLE code that we use at PNC, showed why many experiments are important in this project as well as those in the more obvious Pu/U oxide conventional cores which are of current interest for the DFBR. This point was not appreciated at PNC and is discussed here. The data from the fast spectrum critical experiments made at Los Alamos are described together with information that I have been able to find concerning the uncertainties. The main interest is these experiments has been for prediction of criticality. Consequently, the full covariance information that we would like has not been published. However, the uncertainty in the fuel content is, by far, the major contributor to the uncertainty. The LANL experiments have been a principal leg of the data testing for fast reactors for all versions of ENDF/B in the US. For our work, they provide measurements at Mev energies which are not available from the experiments in the softer-spectrum of the LMFBR.

Computer Programs for Norlinear Algebraic Equations (Development and Benchmark Test of SSL,No.1)

JAERI-M 7335, 88 Pages, 1977/10

JAERI-M-7335.pdf:2.45MB

no abstracts in English

Potential inhalation dose due to remediation activities in the Fukushima exclusion zone

Tschiersch, J.*; Yoshimura, Kazuya; Spielmann, V.*; Hurkamp, K.*; Iijima, Kazuki; Shinonaga, Taeko*; Miyahara, Kaname

no journal, , 

Inhalation dose depends on the kind and amount of inhaled radionuclides, but also on the size of radioactive particles and the solubility of the radionuclides in the lungs. Initial measurements during decontamination provide experimental data of the main parameters. These are particle size distribution with activity median aerodynamic diameter (AMAD) and geometric standard deviation and the solubility in the lungs. The dose assessment is performed according ICRP lung model using the computer code IMBA professional. Doses determined from measured parameters are compared to those using ICRP default values. Variability is studied and the range of potential inhalation dose is assessed.