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Title: Disposal criticality analysis for immobilized Pu: External configurations

Abstract

The problem of potential external criticality is defined according to the following features and issues: The environment outside the waste package is most conveniently divided into 3 zones: (1) Near-field, in the drift, external to the waste package; (2) Near far-field, several meters into the host rock immediately adjacent to the drift; (3) Far far-field, everything beyond the near far-field. These zones have different mechanisms for accumulating a critical mass from the passing waste package outflow. Fissile material can be transported outside of the waste package thereby becoming separated from the neutron absorber. Descriptions of uranium mineral deposits imply that concentrations sufficient for criticality can be accumulated by natural processes, particularly if the uranium is highly enriched. Some configurations of fissile material in the external environment have been identified as having the potential for autocatalytic criticality behavior, but without examining the likelihood of the processes necessary to achieve such configurations. The following factors limit the possibility of external criticality: absence of geologic formations in Yucca Mountain which can cause sufficient concentration, and length of time required to form the typical geologic mineral deposit. The paper summarizes the approach used to analyze criticality and gives results and conclusions of the analysis.

Authors:
 [1];  [2];  [3]
  1. TRW Environmental Safety Systems, Inc., Las Vegas, NV (United States)
  2. Framatome Cogema Fuels, Las Vegas, NV (United States)
  3. SAIC, Las Vegas, NV (United States)
Publication Date:
Research Org.:
TRW Environmental Safety Systems, Inc., Las Vegas, NV (United States)
Sponsoring Org.:
USDOE Office of Civilian Radioactive Waste Management, Washington, DC (United States)
OSTI Identifier:
658248
Report Number(s):
DOE/RW-98005824
ON: DE98005824; NC: NONE; TRN: 98:011297
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Mar 1998
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES; 05 NUCLEAR FUELS; YUCCA MOUNTAIN; RADIOACTIVE WASTE FACILITIES; WASTE FORMS; CRITICALITY; PLUTONIUM; RADIONUCLIDE MIGRATION; GEOCHEMISTRY

Citation Formats

Gottlieb, P, Goluoglu, S, and Cloke, P L. Disposal criticality analysis for immobilized Pu: External configurations. United States: N. p., 1998. Web. doi:10.2172/658248.
Gottlieb, P, Goluoglu, S, & Cloke, P L. Disposal criticality analysis for immobilized Pu: External configurations. United States. https://doi.org/10.2172/658248
Gottlieb, P, Goluoglu, S, and Cloke, P L. 1998. "Disposal criticality analysis for immobilized Pu: External configurations". United States. https://doi.org/10.2172/658248. https://www.osti.gov/servlets/purl/658248.
@article{osti_658248,
title = {Disposal criticality analysis for immobilized Pu: External configurations},
author = {Gottlieb, P and Goluoglu, S and Cloke, P L},
abstractNote = {The problem of potential external criticality is defined according to the following features and issues: The environment outside the waste package is most conveniently divided into 3 zones: (1) Near-field, in the drift, external to the waste package; (2) Near far-field, several meters into the host rock immediately adjacent to the drift; (3) Far far-field, everything beyond the near far-field. These zones have different mechanisms for accumulating a critical mass from the passing waste package outflow. Fissile material can be transported outside of the waste package thereby becoming separated from the neutron absorber. Descriptions of uranium mineral deposits imply that concentrations sufficient for criticality can be accumulated by natural processes, particularly if the uranium is highly enriched. Some configurations of fissile material in the external environment have been identified as having the potential for autocatalytic criticality behavior, but without examining the likelihood of the processes necessary to achieve such configurations. The following factors limit the possibility of external criticality: absence of geologic formations in Yucca Mountain which can cause sufficient concentration, and length of time required to form the typical geologic mineral deposit. The paper summarizes the approach used to analyze criticality and gives results and conclusions of the analysis.},
doi = {10.2172/658248},
url = {https://www.osti.gov/biblio/658248}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Mar 01 00:00:00 EST 1998},
month = {Sun Mar 01 00:00:00 EST 1998}
}