{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/101045"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/101045","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"A kinetic transport model of uranium molecular species formation in a laser ablated plasma plume","abstract":"Nuclear forensics is a technical field of study concerned with the characterization and interpretation of nuclear materials. A central issue in nuclear forensics is the attribution of nuclear devices based on analysis of post-detonation nuclear debris. The issue is complicated by fractionation processes that result in the formation of nuclear debris whose composition does not directly reflect that of the source weapon. Furthermore, the volatility of uranium in atmospheric environments results in complex fractionation patterns that are currently not well understood. Therefore, there is a need to understand uranium chemical fractionation in terms of both the early-stage formation of uranium molecular species and the later-stage debris condensation. In this work, we focus on tackling only the former problem by developing a plasma-chemistry model of uranium molecular species formation during the early stages of nuclear fireball expansion. The model features a newly constructed U$_x$O$_y$ reaction mechanism that consists of 30 reaction channels for 11 uranium molecular species, supplemented by a detailed description of oxygen plasma chemistry. Both the selection of reaction channels and calculation of corresponding rate coefficients is accomplished via a comprehensive literature review and application of basic reaction rate theory. The reaction mechanism is used to model an atmospheric laser ablated uranium plume via both a 0D (global) model and a 2D compressible, reactive multi-species fluid model. The global model is mainly used to provide a detailed kinetic analysis of the early stages of plume evolution, showing both the dissociation and ionization of molecular oxygen and uranium during the pulse heating stage, as well as the sequential formation of increasingly larger uranium molecular oxides that follows in the aftermath of the laser pulse. The 2D fluid model is used to analyze both the kinetics and dynamics of a uranium laser ablation plume during the initial highly reactive stages of expansion, providing a detailed picture of both the complex evolution of internal shocks in the wake of the supersonic shock front expansion and the stratification of the ablation plume into regions of varying reactivity and molecular composition due to multi-species transport. The fluid model also shows that strong reactive heating takes place within the ablation plume, with a high flame temperature of around 8000 K, and that turbulent transport at the plume-material interface plays an important role in cooling the plume down towards ambient conditions.","abstract_html":"Nuclear forensics is a technical field of study concerned with the characterization and interpretation of nuclear materials. A central issue in nuclear forensics is the attribution of nuclear devices based on analysis of post-detonation nuclear debris. The issue is complicated by fractionation processes that result in the formation of nuclear debris whose composition does not directly reflect that of the source weapon. Furthermore, the volatility of uranium in atmospheric environments results in complex fractionation patterns that are currently not well understood. Therefore, there is a need to understand uranium chemical fractionation in terms of both the early-stage formation of uranium molecular species and the later-stage debris condensation. In this work, we focus on tackling only the former problem by developing a plasma-chemistry model of uranium molecular species formation during the early stages of nuclear fireball expansion. The model features a newly constructed U<span class=\"etd-inline-math\"><sub>x</sub></span>O<span class=\"etd-inline-math\"><sub>y</sub></span> reaction mechanism that consists of 30 reaction channels for 11 uranium molecular species, supplemented by a detailed description of oxygen plasma chemistry. Both the selection of reaction channels and calculation of corresponding rate coefficients is accomplished via a comprehensive literature review and application of basic reaction rate theory. The reaction mechanism is used to model an atmospheric laser ablated uranium plume via both a 0D (global) model and a 2D compressible, reactive multi-species fluid model. The global model is mainly used to provide a detailed kinetic analysis of the early stages of plume evolution, showing both the dissociation and ionization of molecular oxygen and uranium during the pulse heating stage, as well as the sequential formation of increasingly larger uranium molecular oxides that follows in the aftermath of the laser pulse. The 2D fluid model is used to analyze both the kinetics and dynamics of a uranium laser ablation plume during the initial highly reactive stages of expansion, providing a detailed picture of both the complex evolution of internal shocks in the wake of the supersonic shock front expansion and the stratification of the ablation plume into regions of varying reactivity and molecular composition due to multi-species transport. The fluid model also shows that strong reactive heating takes place within the ablation plume, with a high flame temperature of around 8000 K, and that turbulent transport at the plume-material interface plays an important role in cooling the plume down towards ambient conditions.","abstract_has_math":true,"creators":["Finko, Mikhail"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Nuclear, Plasma, Radiolgc Engr","degree_department":null,"school":null,"contributors":["Curreli, Davide","Allain, Jean Paul"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2018,"date_issued":"2018-09-04T20:27:24Z","date_published":"2018-09-04T20:27:24Z","updated_at":"2026-07-22T22:24:38Z","subjects":["laser ablation","uranium fractionation","plasma chemistry","atmospheric pressure plasma"],"languages":["en"],"rights":["Copyright 2018 Mikhail Finko"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/101045","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Curreli, Davide","Allain, Jean Paul"]},{"key":"dc:creator","label":"Author","values":["Finko, Mikhail"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-09-04T20:27:24Z","2018-04-24","2018-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear, Plasma, Radiolgc Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["laser ablation","uranium fractionation","plasma chemistry","atmospheric pressure plasma"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2018 Mikhail Finko"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/101045"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Nuclear forensics is a technical field of study concerned with the characterization and interpretation of nuclear materials. A central issue in nuclear forensics is the attribution of nuclear devices based on analysis of post-detonation nuclear debris. The issue is complicated by fractionation processes that result in the formation of nuclear debris whose composition does not directly reflect that of the source weapon. Furthermore, the volatility of uranium in atmospheric environments results in complex fractionation patterns that are currently not well understood. Therefore, there is a need to understand uranium chemical fractionation in terms of both the early-stage formation of uranium molecular species and the later-stage debris condensation. In this work, we focus on tackling only the former problem by developing a plasma-chemistry model of uranium molecular species formation during the early stages of nuclear fireball expansion. The model features a newly constructed U$_x$O$_y$ reaction mechanism that consists of 30 reaction channels for 11 uranium molecular species, supplemented by a detailed description of oxygen plasma chemistry. Both the selection of reaction channels and calculation of corresponding rate coefficients is accomplished via a comprehensive literature review and application of basic reaction rate theory. The reaction mechanism is used to model an atmospheric laser ablated uranium plume via both a 0D (global) model and a 2D compressible, reactive multi-species fluid model. The global model is mainly used to provide a detailed kinetic analysis of the early stages of plume evolution, showing both the dissociation and ionization of molecular oxygen and uranium during the pulse heating stage, as well as the sequential formation of increasingly larger uranium molecular oxides that follows in the aftermath of the laser pulse. The 2D fluid model is used to analyze both the kinetics and dynamics of a uranium laser ablation plume during the initial highly reactive stages of expansion, providing a detailed picture of both the complex evolution of internal shocks in the wake of the supersonic shock front expansion and the stratification of the ablation plume into regions of varying reactivity and molecular composition due to multi-species transport. The fluid model also shows that strong reactive heating takes place within the ablation plume, with a high flame temperature of around 8000 K, and that turbulent transport at the plume-material interface plays an important role in cooling the plume down towards ambient conditions.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2018-08-31 without embargo terms","The student, Mikhail Finko, accepted the attached license on 2018-04-24 at 13:30.","The student, Mikhail Finko, submitted this Thesis for approval on 2018-04-24 at 13:41.","This Thesis was approved for publication on 2018-04-24 at 16:07.","DSpace SAF Submission Ingestion Package generated from Vireo submission #12424 on 2018-08-31 at 17:14:14","Made available in DSpace on 2018-09-04T20:27:24Z (GMT). No. of bitstreams: 3 FINKO-THESIS-2018.pdf: 10261360 bytes, checksum: e58a129d4bac85079982b8a801f83779 (MD5) m-finko-ms.zip: 11869605 bytes, checksum: 3b46f9a9736df67c38e4c4cd2920308f (MD5) LICENSE.txt: 4210 bytes, checksum: 6e6b17ecc03f288082c8271c4122a2b9 (MD5) Previous issue date: 2018-04-24"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["A kinetic transport model of uranium molecular species formation in a laser ablated plasma plume"]}]}],"canonical_facts":{"dc:contributor":["Curreli, Davide","Allain, Jean Paul"],"dc:creator":["Finko, Mikhail"],"dc:date":["2018-09-04T20:27:24Z","2018-04-24","2018-05"],"dc:description":["Nuclear forensics is a technical field of study concerned with the characterization and interpretation of nuclear materials. A central issue in nuclear forensics is the attribution of nuclear devices based on analysis of post-detonation nuclear debris. The issue is complicated by fractionation processes that result in the formation of nuclear debris whose composition does not directly reflect that of the source weapon. Furthermore, the volatility of uranium in atmospheric environments results in complex fractionation patterns that are currently not well understood. Therefore, there is a need to understand uranium chemical fractionation in terms of both the early-stage formation of uranium molecular species and the later-stage debris condensation. In this work, we focus on tackling only the former problem by developing a plasma-chemistry model of uranium molecular species formation during the early stages of nuclear fireball expansion. The model features a newly constructed U$_x$O$_y$ reaction mechanism that consists of 30 reaction channels for 11 uranium molecular species, supplemented by a detailed description of oxygen plasma chemistry. Both the selection of reaction channels and calculation of corresponding rate coefficients is accomplished via a comprehensive literature review and application of basic reaction rate theory. The reaction mechanism is used to model an atmospheric laser ablated uranium plume via both a 0D (global) model and a 2D compressible, reactive multi-species fluid model. The global model is mainly used to provide a detailed kinetic analysis of the early stages of plume evolution, showing both the dissociation and ionization of molecular oxygen and uranium during the pulse heating stage, as well as the sequential formation of increasingly larger uranium molecular oxides that follows in the aftermath of the laser pulse. The 2D fluid model is used to analyze both the kinetics and dynamics of a uranium laser ablation plume during the initial highly reactive stages of expansion, providing a detailed picture of both the complex evolution of internal shocks in the wake of the supersonic shock front expansion and the stratification of the ablation plume into regions of varying reactivity and molecular composition due to multi-species transport. The fluid model also shows that strong reactive heating takes place within the ablation plume, with a high flame temperature of around 8000 K, and that turbulent transport at the plume-material interface plays an important role in cooling the plume down towards ambient conditions.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2018-08-31 without embargo terms","The student, Mikhail Finko, accepted the attached license on 2018-04-24 at 13:30.","The student, Mikhail Finko, submitted this Thesis for approval on 2018-04-24 at 13:41.","This Thesis was approved for publication on 2018-04-24 at 16:07.","DSpace SAF Submission Ingestion Package generated from Vireo submission #12424 on 2018-08-31 at 17:14:14","Made available in DSpace on 2018-09-04T20:27:24Z (GMT). No. of bitstreams: 3 FINKO-THESIS-2018.pdf: 10261360 bytes, checksum: e58a129d4bac85079982b8a801f83779 (MD5) m-finko-ms.zip: 11869605 bytes, checksum: 3b46f9a9736df67c38e4c4cd2920308f (MD5) LICENSE.txt: 4210 bytes, checksum: 6e6b17ecc03f288082c8271c4122a2b9 (MD5) Previous issue date: 2018-04-24"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/101045"],"dc:language":["en"],"dc:rights":["Copyright 2018 Mikhail Finko"],"dc:subject":["laser ablation","uranium fractionation","plasma chemistry","atmospheric pressure plasma"],"dc:title":["A kinetic transport model of uranium molecular species formation in a laser ablated plasma plume"],"dc:type":["text"],"thesis:degree_discipline":["Nuclear, Plasma, Radiolgc Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:38Z"}