Radiation Characterization Summary: ACRR-FRECII Cavity Free-Field Environment at the Core Centerline (ACRR-FRECII-FF-cl)

Parma, Edward J.; Naranjo, Gerald E.; Lippert, Lance L.; Clovis, Ralph D.; Martin, Laura E.; Kaiser, K.; Emmer, Joshua; Greenberg, Joseph; Klein, James; Quirk, Thomas J.; Vehar, David W.; Griffin, P. M.

doi:10.2172/1599978

Cited by 3 publications

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“…These spectra were calculated using 5 billion particles resulting in an average total uncertainty of 0.05%. In this figure it is seen that the 1K, 10K, 50K, and the 100K results are all converging to the same curve and are higher in magnitude than the plot generated for the ACRR FF Characterization Report [1]. At the 0.5 MeV peak, the 10 Point was 112% below the characterized value, the 100 Points was 26% above the characterized value, 1K was 15% above the characterized value, 10K points was 14% above the characterized value, 50K points was 11% above the characterized value, and 100K points was 13% above the characterized value.…”

Section: Point Determinationmentioning

confidence: 68%

“…This paper expands only on the Free Field (FF) environment for the ACRR, but there were eight total environments used for the testing of this method [4]. For the ACRR, the environments tested were FF [1], 44-Inch Lead-Boron (LB44) [5], Polyethylene-Lead-Graphite (PLG) [6] and Cadmium-Polyethylene (CdPoly) [7], and for the FREC-II, the environments tested were FF with rods-up and rods-down [8] and CdPoly with rods-up and rods-down. The unique MCNP models for the analyses are found in the appendices of the characterization reports [1,[3][4][5][6][7].…”

Section: Methodsmentioning

confidence: 99%

“…The fission-product delayed gamma-ray energy spectrum used was for fast U-235 fission in the time interval from 0.2 to 0.5 seconds as given in Engle and Fisher [9] [10]. This spectrum was used since the ACRR is an epithermal system and approximately 87% of the neutron population is above 1 eV and 65% above 1 keV [1]. The total delayed gamma-ray energy released from the fission products used was 6.33 MeV per fission for U-235 fission from ENDF/B-VII.1 [11].…”

Section: Methodsmentioning

confidence: 99%

“…These integral measurements have value in validation but are not useful for spectrum adjustment. However, both passive dosimeters (e.g., TLDs) and active dosimeters (e.g., calorimeters) have some neutron and delayed gamma-ray contribution effects that make interpreting the results much more complex [1].…”

Section: Introductionmentioning

confidence: 99%

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Method for calculating delayed gamma-ray response in the ACRR Central Cavity using MCNP

Moreno

Parma

2023

EPJ Web Conf.

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This document presents the process for a new method developed for the characterization of the delayed gamma-ray radiation fields in pulse reactors like the Annular Core Research Reactor (ACRR). The environments used to test this method in the ACRR Central Cavity were various standard irradiation configurations that used various amounts of moderators and shielding. All environment configurations used the same fission product gamma-ray source energy spectrum. This method required the use of fission sites recorded in the Monte Carlo N-Particle (MCNP) KCODE source tape. A FORTRAN script was written to translate and extract the coordinates for the fission sites. The fission sites were then input into an MCNP source mode input file. Using a MATLAB script, a parametric analysis was performed and determined that 10K fission sites are an appropriate number of coordinates to converge to the correct answer. The method gave excellent results as compared to previous methods. This method can be applied to other pulse research reactors as well.

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Section: Point Determinationmentioning

confidence: 68%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Method for calculating delayed gamma-ray response in the ACRR Central Cavity using MCNP

Moreno

Parma

2023

EPJ Web Conf.

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Nuclear fuels for transient test reactors

Woolstenhulme,

Evans,

Chipman

et al. 2024

Annals of Nuclear Energy

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Neutron and Gamma-Ray Radiation Environments for the Annular Core Research Reactor

Parma

2018

Reactor Dosimetry: 16th International Symposium

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The Sandia National Laboratories’ Annular Core Research Reactor (ACRR) is a unique pool-type research reactor that can pulse up to 300 MJ in energy. The ACRR maintains a dry, 9-in. (22.9 cm) diameter central cavity that extends through the center of the core region and allows for experiment irradiations at the peak neutron flux of the core. An epithermal/fast neutron flux exists in the cavity that allows the neutron energy spectrum to be modified to meet the requirements of the experimenter. Using a moderating material such as water or polyethylene in an annular geometry in the cavity allows a greater thermal neutron energy spectrum to be attained. Using a thermal neutron-absorbing material such as boron carbide or cadmium in an annular geometry in the cavity allows for a more epithermal-fast neutron energy spectrum. The gamma-ray fluence can be decreased by adding a high-Z material such as lead in an annular geometry. The gamma-ray fluence can be enhanced by adding a radiative capture material such as cadmium or gadolinium to a moderating material. Both neutron energy spectrum modification and gamma-ray attenuation/enhancement can be attained simultaneously. Different types of spectrum-modifying “buckets” are currently available for use by experimenters, and others can be custom designed and fabricated. This paper presents the results from the neutron and prompt gamma-ray characterization work for several of the environments in the ACRR central cavity, including the free field, polyethylene-lead-graphite, lead-boron-44 in., and cadmium-polyethylene bucket environments, and for the ACRR-Fueled Ring External Cavity-II. These environments represent typical neutron and gamma-ray spectrum modifications that can be attained at the ACRR.

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Radiation Characterization Summary: ACRR-FRECII Cavity Free-Field Environment at the Core Centerline (ACRR-FRECII-FF-cl)

Cited by 3 publications

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Method for calculating delayed gamma-ray response in the ACRR Central Cavity using MCNP

Method for calculating delayed gamma-ray response in the ACRR Central Cavity using MCNP

Nuclear fuels for transient test reactors

Neutron and Gamma-Ray Radiation Environments for the Annular Core Research Reactor

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