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Title: Criticality Potential of Waste Packages Containing DOE SNF Affected by Igneous Intrusion

Abstract

The Department of Energy (DOE) is currently preparing an application to submit to the U.S. Nuclear Regulatory Commission for a construction authorization for a monitored geologic repository. The repository will contain spent nuclear fuel (SNF) and defense high-level waste (DHLW) in waste packages placed in underground tunnels, or drifts. The primary objective of this paper is to perform a criticality analysis for waste packages containing DOE SNF affected by a disruptive igneous intrusion event in the emplacement drifts. The waste packages feature one DOE SNF canister placed in the center and surrounded by five High-Level Waste (HLW) glass canisters. The effective neutron multiplication factor (k{sub eff}) is determined for potential configurations of the waste package during and after an intrusive igneous event. Due to the complexity of the potential scenarios following an igneous intrusion, finding conservative and bounding configurations with respect to criticality requires some additional considerations. In particular, the geometry of a slumped and damaged waste package must be examined, drift conditions must be modeled over a range of parameters, and the chemical degradation of DOE SNF and waste package materials must be considered for the expected high temperatures. The secondary intent of this calculation is to present amore » method for selecting conservative and bounding configurations for a wide range of end conditions.« less

Authors:
;
Publication Date:
Research Org.:
Yucca Mountain Project, Las Vegas, Nevada
Sponsoring Org.:
USDOE
OSTI Identifier:
893931
Report Number(s):
NA
MOL.20060711.0199, DC# 46889; TRN: US0700080
DOE Contract Number:
NA
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; CONSTRUCTION; CONTAINERS; CRITICALITY; GEOMETRY; GLASS; MULTIPLICATION FACTORS; NEUTRONS; NUCLEAR FUELS; POSITIONING; WASTES

Citation Formats

D.S. Kimball, and C.E. Sanders. Criticality Potential of Waste Packages Containing DOE SNF Affected by Igneous Intrusion. United States: N. p., 2006. Web. doi:10.2172/893931.
D.S. Kimball, & C.E. Sanders. Criticality Potential of Waste Packages Containing DOE SNF Affected by Igneous Intrusion. United States. doi:10.2172/893931.
D.S. Kimball, and C.E. Sanders. Tue . "Criticality Potential of Waste Packages Containing DOE SNF Affected by Igneous Intrusion". United States. doi:10.2172/893931. https://www.osti.gov/servlets/purl/893931.
@article{osti_893931,
title = {Criticality Potential of Waste Packages Containing DOE SNF Affected by Igneous Intrusion},
author = {D.S. Kimball and C.E. Sanders},
abstractNote = {The Department of Energy (DOE) is currently preparing an application to submit to the U.S. Nuclear Regulatory Commission for a construction authorization for a monitored geologic repository. The repository will contain spent nuclear fuel (SNF) and defense high-level waste (DHLW) in waste packages placed in underground tunnels, or drifts. The primary objective of this paper is to perform a criticality analysis for waste packages containing DOE SNF affected by a disruptive igneous intrusion event in the emplacement drifts. The waste packages feature one DOE SNF canister placed in the center and surrounded by five High-Level Waste (HLW) glass canisters. The effective neutron multiplication factor (k{sub eff}) is determined for potential configurations of the waste package during and after an intrusive igneous event. Due to the complexity of the potential scenarios following an igneous intrusion, finding conservative and bounding configurations with respect to criticality requires some additional considerations. In particular, the geometry of a slumped and damaged waste package must be examined, drift conditions must be modeled over a range of parameters, and the chemical degradation of DOE SNF and waste package materials must be considered for the expected high temperatures. The secondary intent of this calculation is to present a method for selecting conservative and bounding configurations for a wide range of end conditions.},
doi = {10.2172/893931},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Feb 07 00:00:00 EST 2006},
month = {Tue Feb 07 00:00:00 EST 2006}
}

Technical Report:

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  • The purpose of this document is to evaluate the potential for criticality for the fissile material that could accumulate in the near-field (invert) and in the far-field (host rock) beneath the U.S. Department of Energy (DOE) spent nuclear fuel (SNF) codisposal waste packages (WPs) as they degrade in the proposed monitored geologic repository at Yucca Mountain. The scope of this calculation is limited to the following DOE SNF types: Shippingport Pressurized Water Reactor (PWR), Enrico Fermi, Fast Flux Test Facility (FFTF), Fort St. Vrain, Melt and Dilute, Shippingport Light Water Breeder Reactor (LWBR), N-Reactor, and Training, Research, Isotope, General Atomicsmore » reactor (TRIGA). The results of this calculation are intended to be used for estimating the probability of criticality in the near-field and in the far-field. There are no limitations on use of the results of this calculation. The calculation is associated with the waste package design and was developed in accordance with the technical work plan, ''Technical Work Plan for: Department of Energy Spent Nuclear Fuel and Plutonium Disposition Work Packages'' (Bechtel SAIC Company, LLC [BSC], 2002a). This calculation is subject to the Quality Assurance Requirements and Description (QARD) per the activity evaluation under work package number P6212310Ml in the technical work plan TWP-MGR-MD-0000 10 REV 01 (BSC 2002a).« less
  • The purpose of this model report is to assess the potential impacts of igneous intrusion on waste packages and waste forms in the emplacement drifts at the Yucca Mountain Repository. The model is based on conceptual models and includes an assessment of deleterious dynamic, thermal, hydrologic, and chemical impacts. This constitutes the waste package and waste form impacts submodel of the Total System Performance Assessment for the License Application (TSPA-LA) model assessing the impacts of a hypothetical igneous intrusion event on the repository total system performance. This submodel is carried out in accordance with Technical Work Plan for Waste Formmore » Degradation Modeling, Testing, and Analyses in Support of SR and LA (BSC 2003a) and Total System Performance Assessment-License Application Methods and Approaches (BSC 2002a). The technical work plan is governed by the procedures of AP-SIII.10Q, Models. Any deviations from the technical work plan are documented in the TSPA-LA approach to implementing the models for waste package and waste form response during igneous intrusion is based on identification of damage zones. Zone 1 includes all emplacement drifts intruded by the basalt dike, and Zone 2 includes all other emplacement drifts in the repository that are not in Zone 1. This model report will document the following model: (1) Impacts of magma intrusion on the components of engineered barrier system (e.g., drip shields and cladding) of emplacement drifts in Zone 1, and the fate of waste forms. (2) Impacts of conducting magma heat and diffusing magma gases on the drip shields, waste packages, and cladding in the Zone 2 emplacement drifts adjacent to the intruded drifts. (3) Impacts of intrusion on Zone 1 in-drift thermal and geochemical environments, including seepage hydrochemistry. The scope of this model only includes impacts to the components stated above, and does not include impacts to other engineered barrier system (EBS) components such as the invert and waste package pallet.« less
  • The purpose of this model report is to assess the potential impacts of igneous intrusion on waste packages and waste forms in the emplacement drifts at the Yucca Mountain Repository. The models are based on conceptual models and includes an assessment of deleterious dynamic, thermal, hydrologic, and chemical impacts. The models described in this report constitute the waste package and waste form impacts submodel of the Total System Performance Assessment for the License Application (TSPA-LA) model assessing the impacts of a hypothetical igneous intrusion event on the repository total system performance. This submodel is carried out in accordance with Technicalmore » Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of LA (BSC 2004 [DIRS:167796]) and Total System Performance Assessment-License Application Methods and Approaches (BSC 2003 [DIRS: 166296]). The technical work plan was prepared in accordance with AP-2.27Q, Planning for Science Activities. Any deviations from the technical work plan are documented in the following sections as they occur. The TSPA-LA approach to implementing the models for waste package and waste form response during igneous intrusion is based on identification of damage zones. Zone 1 includes all emplacement drifts intruded by the basalt dike, and Zone 2 includes all other emplacement drifts in the repository that are not in Zone 1. This model report will document the following model assessments: (1) Mechanical and thermal impacts of basalt magma intrusion on the invert, waste packages and waste forms of the intersected emplacement drifts of Zone 1. (2) Temperature and pressure trends of basaltic magma intrusion intersecting Zone 1 and their potential effects on waste packages and waste forms in Zone 2 emplacement drifts. (3) Deleterious volatile gases, exsolving from the intruded basalt magma and their potential effects on waste packages of Zone 2 emplacement drifts. (4) Post-intrusive physical-chemical environment and seepage water alteration by reaction with intruded basalt. The scope of this model only includes impacts to the components stated above, and does not include impacts to other engineered barrier system (EBS) components such as the waste package pallet. The results of this model report will be used in TSPA for several parameters including (1) temperature of magma (used for the temperature of the waste form after an intrusion) (2) temperature increase in Zone 2 due to intrusion to evaluate impact to Zone 2 waste packages; (3) effects of exsolved gases reaching Zone 2 to evaluate impact to Zone 2 waste packages; and (4) pH and ionic strength of water reacted with basalt to be used in conjunction with ''Dissolved Concentration Limits of Radioactive Elements'' (BSC 2003 [DIRS: 163152]) to determine solubility of spent fuel within the basalt. Ionic strength will also be used in conjunction with ''Waste Form and In-Drift Colloids-Associated Radionuclide Concentrations: Abstraction and Summary'' (BSC 2003 [DIRS: 166845]) for stability of colloids.« less
  • This paper describes a parametric evaluation of the fraction of the pressurized water reactor (PWR) assembly waste stream with the potential for the criticality threshold in a flooded 21 PWR waste package (WP). The parameters considered were: (1) fuel isotopics (i.e., burnup, enrichment, and age), (2) time of WP breach, (3) the degree of basket degradation, (4) the distribution of the resulting corrosion products, and (5) the infiltration rate. For this evaluation, a k{sub eff} of 0.93 was chosen as the threshold for criticality based on the 5% margin of safety required by 10CFR60.131(h), plus an additional 2% to allowmore » for the expected bias and uncertainty in the method of calculation. This and similar evaluations will be used to support probabilistic analyses of WP criticality and the development of WP loading curves.« less