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University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 12-2016 Beta-Delayed Neutron Data and Models for SCALE Kemper Dyar Talley University of Tennessee, Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Nuclear Commons, and the Nuclear Engineering Commons Recommended Citation Talley, Kemper Dyar, "Beta-Delayed Neutron Data and Models for SCALE. " PhD diss., University of Tennessee, 2016. https://trace.tennessee.edu/utk_graddiss/4170 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Kemper Dyar Talley entitled "Beta-Delayed Neutron Data and Models for SCALE." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Energy Science and Engineering. Mark L Williams, Major Professor We have read this dissertation and recommend its acceptance: Robert K. Grzywacz, Larry Townsend, Thomas Handler Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Beta-Delayed Neutron Data and Models for SCALE A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Kemper Dyar Talley December 2016 c by Kemper Dyar Talley, 2016 All Rights Reserved. ii To my friends and family without whom I would be adrift . iii Acknowledgements Thank you . Mark Williams, my advisor, for his patience and direction in this process. His knowledge and direction has been invaluable. Ian Gauld for the many conversations and his thoughts, questions, and his open door. Robert Grywacz for teaching me nuclear physics for two semesters where I learned about the fundamentals. He originally directed me to Miernik's work. William Wieselquist for development of the ORIGEN API and his help with programming which allowed me to implement various theories and experimental data. Erik Olsen, Noah Birge, and Justin Willmert my fellow graduate students in this endeavor. Witek Nazarewicz for his patience and his tutelage at the beginning this process. Without his immense knowledge and prodding I would not have learned as much. Thank you for helping even during a time when I did not know how to help myself. Larry Townsend and Thomas Handler for their teaching and for agreeing to serve on my doctoral committee. I am grateful for your time and discussions. Mark Godwin, my first physics teacher. Without your inspiration, teaching, and friendship I would never have decided to pursue a career in physics. Emil Alexov, my first research mentor, at Clemson University. I'm grateful for the chance to learn the research and publishing process from him. Finally I would like to thank Lee Riedinger, the director of the Bredesen Center for accepting me into the program and helping me find a mentor. His patience is perhaps greatest of all since we both expected this adventure to take much less time. iv The road that stretches before our feet is a challenge to the heart long before it tests the strength of our legs. -Thomas Aquinas v Abstract Recent advancements in experimental and theoretical nuclear physics have yielded new data and models that more accurately describe the decay of fission products compared to historical data currently used for many applications. This work examines the effect of the adopting the Effective Density Model theory for beta-delayed neutron emission probability on calculations of delayed-neutron production and fission product nuclide concentrations after fission bursts as well as the total delayed neutron fraction in comparison with the Keepin 6-group model. We use ORIGEN within the SCALE code package for these calculations. We show quantitative changes to the isotopic concentrations for fallout nuclides and delayed neutron production after fission bursts on the order of a few percent. We also show that the changes are larger at small times for short lived fission products, and that corrections to the cumulative fission product yields has an impact upon the total delayed neutron fraction for 235 U [Uranium 235]. The effect of modeling the β2n [beta delayed double neutron emission] decay mode is also studied but no significant changes from the single beta-delayed neutron emission is currently seen. vi Table of Contents 1 Introduction1 1.1 Nuclear Data and Motivation..........................2 1.2 Nuclear Fission and Mass Tables........................4 1.3 Beta-Decay and Delayed Neutron Emission...................7 2 Methodology 12 2.1 Beta-Delayed Neutron Emission Probability.................. 13 2.2 Kratz-Herrman Formula............................. 14 2.3 Effective Density Model............................. 17 2.3.1 Introduction................................ 17 2.3.2 Comparing EDM to KHF........................ 19 2.3.3 Multiple Neutron Emission........................ 20 2.4 ORIGEN..................................... 21 2.4.1 Introduction................................ 21 2.4.2 Neutron Sources and Decay Data in ORIGEN............. 22 2.4.3 Calculations and Benchmarks...................... 23 2.5 Verification of Data in ENDF.......................... 25 2.6 Microscopic Methods............................... 26 2.6.1 FRDM-QRPA and Hauser-Feshbach.................. 26 3 Results 28 3.1 Differences of Pn in ORIGEN, KHF, and EDM................. 28 vii 3.2 Isotopic Concentration Calculations with Varying Bursts........... 33 3.2.1 235U Fission Burst with Fast Neutrons................. 33 3.2.2 238U Fission Burst with Fast Neutrons................. 35 3.2.3 235U Fission Burst with 14 MeV Neutrons............... 38 3.2.4 239P u Fission Burst with 14MeV Neutrons............... 39 3.3 Multiple Neutron Emission with EDM..................... 39 3.3.1 238U Fission Burst with Fast Neutrons with Multiple Neutron Emission EDM.................................... 40 3.4 Delayed Neutron Sources after Fission Bursts................. 42 3.4.1 238U Fission Burst with Fast Neutrons................. 43 3.5 Discrepancies and Data Errors in ENDF.................... 48 3.5.1 Effects of FPY Changes on Delayed Neutron Fraction of 235U .... 49 4 Conclusions 51 4.1 Pn Changes and Consequences.......................... 51 4.2 Isotope Changes.................................. 51 4.3 Delayed Neutron Production........................... 52 4.4 Delayed Neutron Fraction............................ 52 4.5 General Conclusions............................... 53 4.6 Future Directions................................. 54 Bibliography 57 Appendix 64 A Fission Mass Studies at LANL 65 B Different Model Data Comparisons 67 B.1 SOURCES 4C Delayed Neutron......................... 67 B.2 England and Rider Compilation of Delayed Neutron Data........... 73 viii B.3 Delayed Neutron Fraction in Keepin 6-group Formulation........... 85 C Fallout Nuclides used for Isotopic Analysis 86 C.1 Sample ORIGEN Input.............................. 97 D EDM Data 98 Vita 99 ix List of Tables 2.1 Parameters from fits to the Kratz-Herrmann-Formula from literature..... 16 2.2 Parameters from fits to the Kratz-Herrmann-Formula in different mass regions in Pfeiffer et al................................... 16 2.3 Normalized χ2 (total χ2 divided by the number of experimental points) calculated for Pn predictions of the theoretical models............. 19 2.4 Table of Calculations Represented in this Work................ 24 3.1 235U fast neutron burst. Conc. A is the isotopic concentration in gram-atoms using ENDF/B-VII.I. Conc. B is using EDM. Concentrations given 24 hours after burst..................................... 33 3.2 235U fast neutron burst. Conc. A is the isotopic concentration in gram-atoms using ENDF/B-VII.I. Conc. B is using KHF. Concentrations given 24 hours after burst..................................... 34 3.3 235U fast neutron burst. Conc. A is the isotopic concentration in gram-atoms using ENDF/B-VII.I. Conc. B is using EDM + ENDF/B experimental data. Concentrations given 24 hours after burst.................... 34 3.4 238U fast neutron burst. Conc. A is the isotopic concentration in gram-atoms using ENDF/B-VII.I. Conc. B is using EDM. Concentrations given 24 hours after burst..................................... 35 3.5 238U fast neutron burst. Conc. A is the isotopic concentration in gram-atoms using ENDF/B-VII.I. Conc. B is using KHF. Concentrations given 24 hours after burst..................................... 36 x 3.6 238U fast neutron burst. Conc. A is the isotopic concentration in gram-atoms using ENDF/B-VII.I. Conc. B is using EDM + ENDF/B-VII.I experimental data. Concentrations given 24 hours after burst................. 36 3.7 238U fast neutron burst. Conc. A is the isotopic concentration in gram-atoms using ENDF/B-VII.I. Conc. B is using EDM + ENDF/B-VII.I experimental data. Fallout selection criteria omitted. Concentrations given 24 hours after burst........................................ 37 3.8 235U 14 MeV neutron burst. Conc. A is the isotopic concentration in gram- atoms using ENDF/B-VII.I. Conc. B is using EDM. Concentrations given 24
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