{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85938"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85938","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Advances in the Theory of Persistent Neutron Chains","abstract":"The probability of initiating a persistent neutron chain in a multiplying assembly is calculated by solving the trunking problem associated with the Markov process of nuclear fission. For half a century, this problem has been solved by truncating fission multiplicities at two, an action known to reduce accuracy for both uranium and plutonium, which typically release between two and three neutrons per fission on average, with more possible for increasing neutron energy. The contributions of fission reactions which release larger number of neutrons are thus underestimated. This work extends the fission multiplicity up to fifth order, demonstrates that that upper limit is sufficient to provide confident estimates of initiation probabilities, extends Bell theory to allow for multiple neutron release in a single source event, provides estimates of the errors in current predictive models, and suggests an alternative method of extracting information from a probability distribution function.","abstract_html":"The probability of initiating a persistent neutron chain in a multiplying assembly is calculated by solving the trunking problem associated with the Markov process of nuclear fission. For half a century, this problem has been solved by truncating fission multiplicities at two, an action known to reduce accuracy for both uranium and plutonium, which typically release between two and three neutrons per fission on average, with more possible for increasing neutron energy. The contributions of fission reactions which release larger number of neutrons are thus underestimated. This work extends the fission multiplicity up to fifth order, demonstrates that that upper limit is sufficient to provide confident estimates of initiation probabilities, extends Bell theory to allow for multiple neutron release in a single source event, provides estimates of the errors in current predictive models, and suggests an alternative method of extracting information from a probability distribution function.","abstract_has_math":false,"creators":["Hill, James Lloyd"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Nuclear Engineering","degree_department":null,"school":null,"contributors":["Axford, Roy A."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-28T14:51:21Z","date_published":"2015-09-28T14:51:21Z","updated_at":"2026-07-22T22:26:26Z","subjects":["Engineering, Nuclear"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9834689"],"render_values":[{"text":"(MiAaPQ)AAI9834689","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/85938","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Axford, Roy A."]},{"key":"dc:creator","label":"Author","values":["Hill, James Lloyd"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-28T14:51:21Z","10000-01-01","1998"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Nuclear Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"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":["Engineering, Nuclear"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/85938","(MiAaPQ)AAI9834689"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The probability of initiating a persistent neutron chain in a multiplying assembly is calculated by solving the trunking problem associated with the Markov process of nuclear fission. For half a century, this problem has been solved by truncating fission multiplicities at two, an action known to reduce accuracy for both uranium and plutonium, which typically release between two and three neutrons per fission on average, with more possible for increasing neutron energy. The contributions of fission reactions which release larger number of neutrons are thus underestimated. This work extends the fission multiplicity up to fifth order, demonstrates that that upper limit is sufficient to provide confident estimates of initiation probabilities, extends Bell theory to allow for multiple neutron release in a single source event, provides estimates of the errors in current predictive models, and suggests an alternative method of extracting information from a probability distribution function.","Made available in DSpace on 2015-09-28T14:51:21Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9834689.pdf: 2403657 bytes, checksum: 00f347e2d214c0d6d01f37f51c75cb03 (MD5) Previous issue date: 1998","Embargo set by: Seth Robbins for item 87219 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","101 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998."]},{"key":"dc:title","label":"Title","values":["Advances in the Theory of Persistent Neutron Chains"]}]}],"canonical_facts":{"dc:contributor":["Axford, Roy A."],"dc:creator":["Hill, James Lloyd"],"dc:date":["2015-09-28T14:51:21Z","10000-01-01","1998"],"dc:description":["The probability of initiating a persistent neutron chain in a multiplying assembly is calculated by solving the trunking problem associated with the Markov process of nuclear fission. For half a century, this problem has been solved by truncating fission multiplicities at two, an action known to reduce accuracy for both uranium and plutonium, which typically release between two and three neutrons per fission on average, with more possible for increasing neutron energy. The contributions of fission reactions which release larger number of neutrons are thus underestimated. This work extends the fission multiplicity up to fifth order, demonstrates that that upper limit is sufficient to provide confident estimates of initiation probabilities, extends Bell theory to allow for multiple neutron release in a single source event, provides estimates of the errors in current predictive models, and suggests an alternative method of extracting information from a probability distribution function.","Made available in DSpace on 2015-09-28T14:51:21Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 9834689.pdf: 2403657 bytes, checksum: 00f347e2d214c0d6d01f37f51c75cb03 (MD5) Previous issue date: 1998","Embargo set by: Seth Robbins for item 87219 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","101 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998."],"dc:identifier":["http://hdl.handle.net/2142/85938","(MiAaPQ)AAI9834689"],"dc:language":["eng"],"dc:subject":["Engineering, Nuclear"],"dc:title":["Advances in the Theory of Persistent Neutron Chains"],"dc:type":["text"],"thesis:degree_discipline":["Nuclear Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:26Z"}