{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/45583"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/45583","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Fail-safe source-driven fission and fusion-fission hybrid reactor configurations","abstract":"A source-driven nuclear reactor configuration with a unity infinite medium multiplication factor fission core (1k), is investigated for both fission and fusion-fission hybrid systems. Suchaconfiguration is thought to offer adesirable fail-safe reactor alternative in that the loss of the fission or the fusion neutron sourceswould automatically lead to a shut-down of the system into a stable subcritical statewith an effective multiplication factor of less than unity (1effk). This is sosincethe fission core cannot sustain a chain reactionwithout the presence of the neutron source. A circulating liquid molten salt using the Th-233Ufuel cycle,where the fission products are continuously extracted,further contributes to the fail-safe characteristic by avoiding the cooling neededfor the decay heat or afterheat after reactor shut-down. Through the extraction of the 233Parelatively long-lived12( 27 )T daysprecursorisotope,and allowing it sufficient time to decay intoits 233Udaughter, breeding in either thermal orfast neutron spectrais a distinct possibility.The presence of trace amounts of 232Uand thestrong gamma-emitting 208Tldaughter isotope offers a desirable non-proliferation characteristicfor the cycle.As a proof of principle, a simplifiedanalytical one-group neutronics analysis isfirstattemptedfor the pure fission core system. This is then supplemented withnumerical one-group criticality calculationsusing an iterative finite-difference methodology. Further, amore detailed continuous energyMonte Carlo neutronics analysis of the fission core reactor driven by a 233Ufissionneutron source, Deuterium-Tritium(DT) and Deuterium-Deuterium (DD) fusion neutron sourceswas conducted usingthe MCNP5computer code.The first system studiedwas a spherical reactor core with a unity infinite medium multiplication factor (1k)and surrounded by a reflector. A 232Th and 233U FLiBe molten salt wasused as the fuel in the core. The reactor is made criticalwith the addition of a thin region of FLiBe salt with a spike of fissile material (233U). With a kin the core and total system effkof unity, the flux profile for the system becomes flat, resulting in uniform fuel burnup andpower profile. Such a configuration was found to have a conversion ratio of 1.4 in the core. However, 233U production in the core would not be able to replace the 233U consumed in the fissile source iiiregionwithout exceeding a 3-5 percent concentration. This maybe possibly achievedusing other stockpiled fissile materials such as 235Uor Pu239at higher enrichment levels.Alternatively, the fissile source region can be replaced by a fusion neutron source such as from DT or DD fusion. The systemstudiedconsisted of a cylindrical core surroundedby a fusion source. It is envisioned that the source could be provided by several cylindrical electrodynamic inertial fusion generators. A small 318 MWthsystem can be driven by a 22.3 MWDT source or a 9 MW DD source. A DT system would be able to achieve fissile breeding at the expenseof requiring an outside source of tritium. Alternatively, a DD system can use a sodium-based moltensalt and breed 233U witha doubling time of 9.2 years.The results of the investigationsuggestthat source-driven systemsassociated with a molten-saltcan be contemplatedwith substantialfail-safe benefits. Running a subcritical reactor eliminates the need for excessive reactivity control systems and providessafety in a loss of power transient situation. Furthermore, utilizing a fissile neutron source yieldsbeneficial power and flux profiles. Lastly, such systems can breed fissile material and support afuture alternative Th-233Uthorium fuel cycle.","abstract_html":"A source-driven nuclear reactor configuration with a unity infinite medium multiplication factor fission core (1k), is investigated for both fission and fusion-fission hybrid systems. Suchaconfiguration is thought to offer adesirable fail-safe reactor alternative in that the loss of the fission or the fusion neutron sourceswould automatically lead to a shut-down of the system into a stable subcritical statewith an effective multiplication factor of less than unity (1effk). This is sosincethe fission core cannot sustain a chain reactionwithout the presence of the neutron source. A circulating liquid molten salt using the Th-233Ufuel cycle,where the fission products are continuously extracted,further contributes to the fail-safe characteristic by avoiding the cooling neededfor the decay heat or afterheat after reactor shut-down. Through the extraction of the 233Parelatively long-lived12( 27 )T daysprecursorisotope,and allowing it sufficient time to decay intoits 233Udaughter, breeding in either thermal orfast neutron spectrais a distinct possibility.The presence of trace amounts of 232Uand thestrong gamma-emitting 208Tldaughter isotope offers a desirable non-proliferation characteristicfor the cycle.As a proof of principle, a simplifiedanalytical one-group neutronics analysis isfirstattemptedfor the pure fission core system. This is then supplemented withnumerical one-group criticality calculationsusing an iterative finite-difference methodology. Further, amore detailed continuous energyMonte Carlo neutronics analysis of the fission core reactor driven by a 233Ufissionneutron source, Deuterium-Tritium(DT) and Deuterium-Deuterium (DD) fusion neutron sourceswas conducted usingthe MCNP5computer code.The first system studiedwas a spherical reactor core with a unity infinite medium multiplication factor (1k)and surrounded by a reflector. A 232Th and 233U FLiBe molten salt wasused as the fuel in the core. The reactor is made criticalwith the addition of a thin region of FLiBe salt with a spike of fissile material (233U). With a kin the core and total system effkof unity, the flux profile for the system becomes flat, resulting in uniform fuel burnup andpower profile. Such a configuration was found to have a conversion ratio of 1.4 in the core. However, 233U production in the core would not be able to replace the 233U consumed in the fissile source iiiregionwithout exceeding a 3-5 percent concentration. This maybe possibly achievedusing other stockpiled fissile materials such as 235Uor Pu239at higher enrichment levels.Alternatively, the fissile source region can be replaced by a fusion neutron source such as from DT or DD fusion. The systemstudiedconsisted of a cylindrical core surroundedby a fusion source. It is envisioned that the source could be provided by several cylindrical electrodynamic inertial fusion generators. A small 318 MWthsystem can be driven by a 22.3 MWDT source or a 9 MW DD source. A DT system would be able to achieve fissile breeding at the expenseof requiring an outside source of tritium. Alternatively, a DD system can use a sodium-based moltensalt and breed 233U witha doubling time of 9.2 years.The results of the investigationsuggestthat source-driven systemsassociated with a molten-saltcan be contemplatedwith substantialfail-safe benefits. Running a subcritical reactor eliminates the need for excessive reactivity control systems and providessafety in a loss of power transient situation. Furthermore, utilizing a fissile neutron source yieldsbeneficial power and flux profiles. Lastly, such systems can breed fissile material and support afuture alternative Th-233Uthorium fuel cycle.","abstract_has_math":false,"creators":["Singh, Monish"],"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":["Ragheb, Magdi"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-08-22T16:48:35Z","date_published":"2013-08-22T16:48:35Z","updated_at":"2026-07-22T22:25:36Z","subjects":["Fusion-Fission Hybrid","Fail-Safe Reactor","Liquid Fluoride Thorium Reactor (LFTR)","Thorium Reactor"],"languages":["en"],"rights":["Copyright 2013 Monish Singh"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/45583","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Ragheb, Magdi"]},{"key":"dc:creator","label":"Author","values":["Singh, Monish"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-08-22T16:48:35Z","2015-08-22T10:00:54Z","2013-08"]},{"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":["Fusion-Fission Hybrid","Fail-Safe Reactor","Liquid Fluoride Thorium Reactor (LFTR)","Thorium Reactor"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2013 Monish Singh"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/45583"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["A source-driven nuclear reactor configuration with a unity infinite medium multiplication factor fission core (1k), is investigated for both fission and fusion-fission hybrid systems. Suchaconfiguration is thought to offer adesirable fail-safe reactor alternative in that the loss of the fission or the fusion neutron sourceswould automatically lead to a shut-down of the system into a stable subcritical statewith an effective multiplication factor of less than unity (1effk). This is sosincethe fission core cannot sustain a chain reactionwithout the presence of the neutron source. A circulating liquid molten salt using the Th-233Ufuel cycle,where the fission products are continuously extracted,further contributes to the fail-safe characteristic by avoiding the cooling neededfor the decay heat or afterheat after reactor shut-down. Through the extraction of the 233Parelatively long-lived12( 27 )T daysprecursorisotope,and allowing it sufficient time to decay intoits 233Udaughter, breeding in either thermal orfast neutron spectrais a distinct possibility.The presence of trace amounts of 232Uand thestrong gamma-emitting 208Tldaughter isotope offers a desirable non-proliferation characteristicfor the cycle.As a proof of principle, a simplifiedanalytical one-group neutronics analysis isfirstattemptedfor the pure fission core system. This is then supplemented withnumerical one-group criticality calculationsusing an iterative finite-difference methodology. Further, amore detailed continuous energyMonte Carlo neutronics analysis of the fission core reactor driven by a 233Ufissionneutron source, Deuterium-Tritium(DT) and Deuterium-Deuterium (DD) fusion neutron sourceswas conducted usingthe MCNP5computer code.The first system studiedwas a spherical reactor core with a unity infinite medium multiplication factor (1k)and surrounded by a reflector. A 232Th and 233U FLiBe molten salt wasused as the fuel in the core. The reactor is made criticalwith the addition of a thin region of FLiBe salt with a spike of fissile material (233U). With a kin the core and total system effkof unity, the flux profile for the system becomes flat, resulting in uniform fuel burnup andpower profile. Such a configuration was found to have a conversion ratio of 1.4 in the core. However, 233U production in the core would not be able to replace the 233U consumed in the fissile source iiiregionwithout exceeding a 3-5 percent concentration. This maybe possibly achievedusing other stockpiled fissile materials such as 235Uor Pu239at higher enrichment levels.Alternatively, the fissile source region can be replaced by a fusion neutron source such as from DT or DD fusion. The systemstudiedconsisted of a cylindrical core surroundedby a fusion source. It is envisioned that the source could be provided by several cylindrical electrodynamic inertial fusion generators. A small 318 MWthsystem can be driven by a 22.3 MWDT source or a 9 MW DD source. A DT system would be able to achieve fissile breeding at the expenseof requiring an outside source of tritium. Alternatively, a DD system can use a sodium-based moltensalt and breed 233U witha doubling time of 9.2 years.The results of the investigationsuggestthat source-driven systemsassociated with a molten-saltcan be contemplatedwith substantialfail-safe benefits. Running a subcritical reactor eliminates the need for excessive reactivity control systems and providessafety in a loss of power transient situation. Furthermore, utilizing a fissile neutron source yieldsbeneficial power and flux profiles. Lastly, such systems can breed fissile material and support afuture alternative Th-233Uthorium fuel cycle.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-07-08T15:13:55Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 SINGH_MONISH.docx: 4397896 bytes, checksum: 92835462d73dcea263b905b99b2a6884 (MD5) SINGH_MONISH.pdf: 2776083 bytes, checksum: 2cb8d004a685b5c6b85e5277d142234d (MD5)","Made available in DSpace on 2013-08-22T16:48:35Z (GMT). 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Suchaconfiguration is thought to offer adesirable fail-safe reactor alternative in that the loss of the fission or the fusion neutron sourceswould automatically lead to a shut-down of the system into a stable subcritical statewith an effective multiplication factor of less than unity (1effk). This is sosincethe fission core cannot sustain a chain reactionwithout the presence of the neutron source. A circulating liquid molten salt using the Th-233Ufuel cycle,where the fission products are continuously extracted,further contributes to the fail-safe characteristic by avoiding the cooling neededfor the decay heat or afterheat after reactor shut-down. Through the extraction of the 233Parelatively long-lived12( 27 )T daysprecursorisotope,and allowing it sufficient time to decay intoits 233Udaughter, breeding in either thermal orfast neutron spectrais a distinct possibility.The presence of trace amounts of 232Uand thestrong gamma-emitting 208Tldaughter isotope offers a desirable non-proliferation characteristicfor the cycle.As a proof of principle, a simplifiedanalytical one-group neutronics analysis isfirstattemptedfor the pure fission core system. This is then supplemented withnumerical one-group criticality calculationsusing an iterative finite-difference methodology. Further, amore detailed continuous energyMonte Carlo neutronics analysis of the fission core reactor driven by a 233Ufissionneutron source, Deuterium-Tritium(DT) and Deuterium-Deuterium (DD) fusion neutron sourceswas conducted usingthe MCNP5computer code.The first system studiedwas a spherical reactor core with a unity infinite medium multiplication factor (1k)and surrounded by a reflector. A 232Th and 233U FLiBe molten salt wasused as the fuel in the core. The reactor is made criticalwith the addition of a thin region of FLiBe salt with a spike of fissile material (233U). With a kin the core and total system effkof unity, the flux profile for the system becomes flat, resulting in uniform fuel burnup andpower profile. Such a configuration was found to have a conversion ratio of 1.4 in the core. However, 233U production in the core would not be able to replace the 233U consumed in the fissile source iiiregionwithout exceeding a 3-5 percent concentration. This maybe possibly achievedusing other stockpiled fissile materials such as 235Uor Pu239at higher enrichment levels.Alternatively, the fissile source region can be replaced by a fusion neutron source such as from DT or DD fusion. The systemstudiedconsisted of a cylindrical core surroundedby a fusion source. It is envisioned that the source could be provided by several cylindrical electrodynamic inertial fusion generators. A small 318 MWthsystem can be driven by a 22.3 MWDT source or a 9 MW DD source. A DT system would be able to achieve fissile breeding at the expenseof requiring an outside source of tritium. Alternatively, a DD system can use a sodium-based moltensalt and breed 233U witha doubling time of 9.2 years.The results of the investigationsuggestthat source-driven systemsassociated with a molten-saltcan be contemplatedwith substantialfail-safe benefits. Running a subcritical reactor eliminates the need for excessive reactivity control systems and providessafety in a loss of power transient situation. Furthermore, utilizing a fissile neutron source yieldsbeneficial power and flux profiles. Lastly, such systems can breed fissile material and support afuture alternative Th-233Uthorium fuel cycle.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-07-08T15:13:55Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 SINGH_MONISH.docx: 4397896 bytes, checksum: 92835462d73dcea263b905b99b2a6884 (MD5) SINGH_MONISH.pdf: 2776083 bytes, checksum: 2cb8d004a685b5c6b85e5277d142234d (MD5)","Made available in DSpace on 2013-08-22T16:48:35Z (GMT). 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