2026-09-19T12:53:33Zhttps://dspace.mit.edu/server/oai/request

oai:dspace.mit.edu:1721.1/416922022-01-13T07:54:37Zcom_1721.1_7582com_1721.1_7581col_1721.1_131024

Mujid Kazimi. Reese, Drew A. (Drew Amelia) Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering. Massachusetts Institute of Technology. Department of Nuclear Science and Engineering 2008-05-19T16:09:09Z 2008-05-19T16:09:09Z 2007 2007 http://hdl.handle.net/1721.1/41692 221276787 Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007. Includes bibliographical references (p. 33). As the increasing demand for nuclear energy results in larger spent fuel volume, implementation of longer fuel cycles incorporating higher burnup are becoming common. Understanding the effect of higher burnup on the spent fuel composition and radioactive properties is essential to ensure that spent fuel receives proper cooling in storage before it is sent to a disposal site or proper treatment and reprocessing if its useful content is to be extracted prior to disposal. Using CASMO-4, a standard Westinghouse 4-loop pressurized water reactor model was created and simulated with a three batch fuel cycle. U-235 enrichment was adjusted to achieve fuel burnups of 30, 50, 70 and 100 MWD per kg of initial uranium. These burnups demanded reload enrichments of 3.15%, 4.63%, 6.26% and 9.01% U-235 w/o respectively. The resultant spent fuel transuranic isotopic compositions were then provided as input into ORIGEN to study the decay behavior of the spent fuel. It was found that when burnup increased from 30 MWD/kg to 100 MWD/kg, the activity more than doubled due to the decreased Pu-241 content and the increased Np-239 presence. More importantly, the activity per MWD significantly decreased despite absolute increases in unit mass. The net result is that the half-life of high burnup fuels is greatly increased in comparison to low burnup fuels for the first decade of life. Beginning from day 14 after shutdown and until 10 years later, the 100 MWD/kg fuel has a half-life of 129 days while the 30 MWD/kg spent fuel has a half life of 5 days. Previous work has suggested that different trends dominate decay behavior from years 10 to 100 years following discharge. by Drew A. Reese. S.B. 53 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Nuclear Science and Engineering. Dependence of transuranic content in spent fuel on fuel burnup Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="ba88479b-9f38-492c-9501-f2a73d1965f2"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Dependence of transuranic content in spent fuel on fuel burnup</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2007</PublicationDate> <Authors> <Author> <DisplayName>Reese, Drew A. (Drew Amelia)</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Nuclear Science and Engineering.</Keyword> <Abstract>As the increasing demand for nuclear energy results in larger spent fuel volume, implementation of longer fuel cycles incorporating higher burnup are becoming common. Understanding the effect of higher burnup on the spent fuel composition and radioactive properties is essential to ensure that spent fuel receives proper cooling in storage before it is sent to a disposal site or proper treatment and reprocessing if its useful content is to be extracted prior to disposal. Using CASMO-4, a standard Westinghouse 4-loop pressurized water reactor model was created and simulated with a three batch fuel cycle. U-235 enrichment was adjusted to achieve fuel burnups of 30, 50, 70 and 100 MWD per kg of initial uranium. These burnups demanded reload enrichments of 3.15%, 4.63%, 6.26% and 9.01% U-235 w/o respectively. The resultant spent fuel transuranic isotopic compositions were then provided as input into ORIGEN to study the decay behavior of the spent fuel. It was found that when burnup increased from 30 MWD/kg to 100 MWD/kg, the activity more than doubled due to the decreased Pu-241 content and the increased Np-239 presence. More importantly, the activity per MWD significantly decreased despite absolute increases in unit mass. The net result is that the half-life of high burnup fuels is greatly increased in comparison to low burnup fuels for the first decade of life. Beginning from day 14 after shutdown and until 10 years later, the 100 MWD/kg fuel has a half-life of 129 days while the 30 MWD/kg spent fuel has a half life of 5 days. Previous work has suggested that different trends dominate decay behavior from years 10 to 100 years following discharge.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>