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Title: ORALLOY (93.15 235U) METAL ANNULI WITH BERYLLIUM CORE

Abstract

A variety of critical experiments were constructed of enriched uranium metal during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, two were performed that consisted of uranium metal annuli with a solid beryllium metal core. The outer diameter of the annuli was approximately 13 or 15 inches with an inner diameter of 7 inches. The diameter of the core was approximately 7 inches. The critical height of the configurations was approximately 5 and 4 inches, respectively. The uranium annuli consisted of multiple stacked rings with diametral thicknesses of approximately 2 inches apiece and varying heights. The 15-inch experiment was performed on June 4, 1963, and the 13-inch experiment on July 12, 1963 by J. T. Mihalczomore » and R. G. Taylor (Ref. 1) with accompanying logbook. Both detailed and simplified model specifications are provided in this evaluation. Both of these fast-spectra experiments were determined to represent acceptable benchmarks. The calculated eigenvalues for both the detailed and simple models are within approximately 0.6% of the benchmark values, but significantly greater than 3s from the benchmark value because the uncertainty in the benchmark is very small: <±0.0004 (1s). There is significant variability between results using different neutron cross section libraries, the greatest being a ?keff of ~0.67%. Unreflected and unmoderated experiments with the same highly enriched uranium metal parts were performed at the Oak Ridge Critical Experiments Facility in the 1960s and are evaluated in HEU MET FAST 051. Thin graphite reflected (2 inches or less) experiments also using the same highly enriched uranium metal parts are evaluated in HEU MET FAST 071. Polyethylene-reflected configurations are evaluated in HEU-MET-FAST-076. A stack of highly enriched metal discs with a thick beryllium reflector is evaluated in HEU-MET-FAST-069.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org.:
DOE - NE
OSTI Identifier:
1004261
Report Number(s):
INL/EXT-10-18065
TRN: US1100957
DOE Contract Number:  
DE-AC07-05ID14517
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 97 MATHEMATICS AND COMPUTING; BENCHMARKS; BERYLLIUM; CALCULATION METHODS; CASTING; CRITICALITY; CROSS SECTIONS; EIGENVALUES; ENRICHED URANIUM; GRAPHITE; HIGHLY ENRICHED URANIUM; NEUTRONS; OR-CEF REACTOR; POLYETHYLENES; SAFETY; SPECIFICATIONS; STORAGE; URANIUM; VERIFICATION; Y-12 PLANT; benchmark; beryllium; critical experiments; highly enriched uranium; ICSBEP; oralloy

Citation Formats

Bess, John D., Montierth, Leland M., Reed, Raymond L., and Mihalczo, John T.. ORALLOY (93.15 235U) METAL ANNULI WITH BERYLLIUM CORE. United States: N. p., 2010. Web. doi:10.2172/1004261.
Bess, John D., Montierth, Leland M., Reed, Raymond L., & Mihalczo, John T.. ORALLOY (93.15 235U) METAL ANNULI WITH BERYLLIUM CORE. United States. https://doi.org/10.2172/1004261
Bess, John D., Montierth, Leland M., Reed, Raymond L., and Mihalczo, John T.. 2010. "ORALLOY (93.15 235U) METAL ANNULI WITH BERYLLIUM CORE". United States. https://doi.org/10.2172/1004261. https://www.osti.gov/servlets/purl/1004261.
@article{osti_1004261,
title = {ORALLOY (93.15 235U) METAL ANNULI WITH BERYLLIUM CORE},
author = {Bess, John D. and Montierth, Leland M. and Reed, Raymond L. and Mihalczo, John T.},
abstractNote = {A variety of critical experiments were constructed of enriched uranium metal during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, two were performed that consisted of uranium metal annuli with a solid beryllium metal core. The outer diameter of the annuli was approximately 13 or 15 inches with an inner diameter of 7 inches. The diameter of the core was approximately 7 inches. The critical height of the configurations was approximately 5 and 4 inches, respectively. The uranium annuli consisted of multiple stacked rings with diametral thicknesses of approximately 2 inches apiece and varying heights. The 15-inch experiment was performed on June 4, 1963, and the 13-inch experiment on July 12, 1963 by J. T. Mihalczo and R. G. Taylor (Ref. 1) with accompanying logbook. Both detailed and simplified model specifications are provided in this evaluation. Both of these fast-spectra experiments were determined to represent acceptable benchmarks. The calculated eigenvalues for both the detailed and simple models are within approximately 0.6% of the benchmark values, but significantly greater than 3s from the benchmark value because the uncertainty in the benchmark is very small: <±0.0004 (1s). There is significant variability between results using different neutron cross section libraries, the greatest being a ?keff of ~0.67%. Unreflected and unmoderated experiments with the same highly enriched uranium metal parts were performed at the Oak Ridge Critical Experiments Facility in the 1960s and are evaluated in HEU MET FAST 051. Thin graphite reflected (2 inches or less) experiments also using the same highly enriched uranium metal parts are evaluated in HEU MET FAST 071. Polyethylene-reflected configurations are evaluated in HEU-MET-FAST-076. A stack of highly enriched metal discs with a thick beryllium reflector is evaluated in HEU-MET-FAST-069.},
doi = {10.2172/1004261},
url = {https://www.osti.gov/biblio/1004261}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2010},
month = {9}
}