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Title: Benchmark test of neutron transport calculations: Indium, nickel, gold, europium, and cobalt activation with and without energy moderated fission neutrons by iron simulating the Hiroshima atomic bomb casing

Abstract

A benchmark test of the Monte Carlo neutron and photon transport code system (MCNP) was performed using a bare- and energy-moderated {sup 252}Cf fission neutron source which was obtained by transmission through 10-cm-thick iron. An iron plate was used to simulate the effect of the Hiroshima atomic bomb casing. This test includes the activation of indium and nickel for fast neutrons and gold, europium, and cobalt for thermal and epithermal neutrons, which were inserted in the moderators. The latter two activations are also to validate {sup 152}Eu and {sup 60}Co activity data obtained from the atomic bomb-exposed specimens collected at Hiroshima and Nagasaki, Japan. The neutron moderators used were Lucite and Nylon 6 and the total thickness of each moderator was 60 cm or 65 cm. Measured activity data (reaction yield) of the neutron-irradiated detectors in these moderators decreased to about 1/1,000th or 1/10,000th, which corresponds to about 1,500 m ground distance from the hypocenter in Hiroshima. For all of the indium, nickel, and gold activity data, the measured and calculated values agreed within 25%, and the corresponding values for europium and cobalt were within 40%. From this study, the MCNP code was found to be accurate enough for themore » bare- and energy-moderated {sup 252}Cf neutron activation calculations of these elements using moderators containing hydrogen, carbon, nitrogen, and oxygen. 18 refs., 10 figs., 4 tabs.« less

Authors:
; ; ; ; ;  [1];  [2]
  1. Hiroshima Univ., Higashi-Hiroshima (Japan)
  2. Kure Women`s College, Hiroshima-ken (Japan)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
54456
Resource Type:
Journal Article
Resource Relation:
Journal Name: Health Physics; Journal Volume: 67; Journal Issue: 4; Other Information: PBD: Oct 1994
Country of Publication:
United States
Language:
English
Subject:
56 BIOLOGY AND MEDICINE, APPLIED STUDIES; PHOTON TRANSPORT; MEASURING METHODS; NEUTRON TRANSPORT; MONTE CARLO METHOD; VALIDATION; NUCLEAR WEAPONS; SIMULATION; EUROPIUM 152; CALIFORNIUM 252; NEUTRON SOURCES; COBALT 60; MODERATING DETECTORS; FISSION SPECTRA

Citation Formats

Iwatani, Kazuo, Shizuma, Kiyoshi, Hasai, Hiromi, Hoshi, Masaharu, Hiraoka, Masayuki, Hayakawa, Norihiko, and Oka, Takamitsu. Benchmark test of neutron transport calculations: Indium, nickel, gold, europium, and cobalt activation with and without energy moderated fission neutrons by iron simulating the Hiroshima atomic bomb casing. United States: N. p., 1994. Web. doi:10.1097/00004032-199410000-00006.
Iwatani, Kazuo, Shizuma, Kiyoshi, Hasai, Hiromi, Hoshi, Masaharu, Hiraoka, Masayuki, Hayakawa, Norihiko, & Oka, Takamitsu. Benchmark test of neutron transport calculations: Indium, nickel, gold, europium, and cobalt activation with and without energy moderated fission neutrons by iron simulating the Hiroshima atomic bomb casing. United States. doi:10.1097/00004032-199410000-00006.
Iwatani, Kazuo, Shizuma, Kiyoshi, Hasai, Hiromi, Hoshi, Masaharu, Hiraoka, Masayuki, Hayakawa, Norihiko, and Oka, Takamitsu. 1994. "Benchmark test of neutron transport calculations: Indium, nickel, gold, europium, and cobalt activation with and without energy moderated fission neutrons by iron simulating the Hiroshima atomic bomb casing". United States. doi:10.1097/00004032-199410000-00006.
@article{osti_54456,
title = {Benchmark test of neutron transport calculations: Indium, nickel, gold, europium, and cobalt activation with and without energy moderated fission neutrons by iron simulating the Hiroshima atomic bomb casing},
author = {Iwatani, Kazuo and Shizuma, Kiyoshi and Hasai, Hiromi and Hoshi, Masaharu and Hiraoka, Masayuki and Hayakawa, Norihiko and Oka, Takamitsu},
abstractNote = {A benchmark test of the Monte Carlo neutron and photon transport code system (MCNP) was performed using a bare- and energy-moderated {sup 252}Cf fission neutron source which was obtained by transmission through 10-cm-thick iron. An iron plate was used to simulate the effect of the Hiroshima atomic bomb casing. This test includes the activation of indium and nickel for fast neutrons and gold, europium, and cobalt for thermal and epithermal neutrons, which were inserted in the moderators. The latter two activations are also to validate {sup 152}Eu and {sup 60}Co activity data obtained from the atomic bomb-exposed specimens collected at Hiroshima and Nagasaki, Japan. The neutron moderators used were Lucite and Nylon 6 and the total thickness of each moderator was 60 cm or 65 cm. Measured activity data (reaction yield) of the neutron-irradiated detectors in these moderators decreased to about 1/1,000th or 1/10,000th, which corresponds to about 1,500 m ground distance from the hypocenter in Hiroshima. For all of the indium, nickel, and gold activity data, the measured and calculated values agreed within 25%, and the corresponding values for europium and cobalt were within 40%. From this study, the MCNP code was found to be accurate enough for the bare- and energy-moderated {sup 252}Cf neutron activation calculations of these elements using moderators containing hydrogen, carbon, nitrogen, and oxygen. 18 refs., 10 figs., 4 tabs.},
doi = {10.1097/00004032-199410000-00006},
journal = {Health Physics},
number = 4,
volume = 67,
place = {United States},
year = 1994,
month =
}
  • The /sup 152/Eu activity depth profile of a granite pillar of the Motoyasu bridge located 132 m from the Hiroshima atomic bomb hypocenter was assessed. The pillars each measured 82 cm in depth, 82 cm in width and 193 cm in height. One of the pillars was bored and 6.8-cm-diameter core samples were removed and cut into 2-cm-thick disks. Two gamma rays of /sup 152/Eu, 122 keV and 344 keV, in each disk were measured using a low background, gamma-ray spectrometer, and the activity distribution was determined as a function of depth in the granite. A concentration of stable Eumore » in the granite was determined by activation analysis. The specific radioactivity of /sup 152/Eu and /sup 154/Eu at the pillar surface was determined to have been 117 and 24 Bq per mg Eu, respectively, at the time of detonation. The value of /sup 152/Eu agrees within 20% of that calculated by Loewe. The depth profile of /sup 152/Eu in granite demonstrates a distinct difference from the estimates made only by thermal neutrons. Present data provide valuable information for the analysis of the neutron spectrum of the Hiroshima atomic bomb and its intensity.« less
  • Iron is the most fundamental composition of structural and shield material for fusion reactors. Neutron spectra below 10 keV in an iron shield assembly bombarded by deuterium-tritium neutrons are measured with accuracy between 5 and 13% by adopting the slowing-down time method. The measurement supplemented previous spectrum measurements for higher energies so that the neutron spectrum in the whole energy range from 14 MeV down to 0.3 eV is now available. Benchmark tests of iron data in JENDL-3.1, JENDL-3.2, JENDL fusion file, and FENDL/E-1.0 were carried out in the whole energy range with experimental uncertainty at {approximately}10% by utilizing themore » present and previous experiments. As a result, it was found that cross-section data in the newer versions of JENDL were improved in terms of agreement with the experiment. Calculation with JENDL fusion file and FENDL/E-1.0 could predict neutron fluxes in the whole energy range within 20 and 15%, respectively. Possible over- and underestimations for nonelastic and elastic cross sections, respectively, at 14 MeV in all JENDLs were pointed out. It was confirmed that low-energy neutron fluxes were very sensitive to Q values for discrete inelastic cross sections of natural iron and {sup 57}Fe(n,n{prime}{sub 1}) reaction, which were not adequately treated in JENDL-3.1.« less
  • Several fast-neutron activation reactions for copper, europium, hafnium, iron, nickel, silver, terbium and titanium that are important to fusion energy have been investigated in three distinct neutron fields generated by accelerators at Argonne National Laboratory ANL and Los Alamos National Laboratory (LANL), U.S.A., and Japan Atomic Energy Research Institute (JAERI), Tokai, Japan. The experimental data acquired from this collaboration, which has been organized by the International Atomic Energy Agency, include both differential cross sections at 10.0 and 14.7 MeV and integral cross sections for the Be(d,n) thick-target spectrum produced by 7-MeV deuterons. {sup 58}Ni(n,p){sup 58g + m}Co and {sup 93}Nbmore » (n,2n){sup 92m}Nb were used as neutron fluence standards, and the {sup 238}U(n,f) cross section was measured at 10.0 MeV to validate the experimental techniques. Measured differential cross sections are compared with corresponding experimental data from the literature and with values obtained from nuclear model calculations and evaluations. Measured integral cross sections are compared with some earlier experimental results from ANL and with calculated values based on available differential cross-section excitation functions and various representations of the Be(d,n) neutron spectrum. Reasonably good agreement is observed in many of these comparisons.« less