Download or read book Mixed Core Conversion Study with HEU and LEU Fuels written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of a mixed core study are presented for gradual replacement of HEU fuel with LEU fuel using the IAEA generic 10 MW reactor as an example. The key parameters show that the transition can be accomplished safely and economically.
Download or read book LEU HEU Mixed Core Conversion Thermal hydraulic Analysis and Coolant System Upgrade Assessment for the MIT Research Reactor written by Yinjie Zhao and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MIT Research Reactor (MITR) is in the process of converting from the current 93%-enriched U-235 highly-enriched uranium (HEU) fuel to the low enriched uranium (LEU, 20%-enriched U-235) fuel, as part of the global non-proliferation initiatives. A high-density, monolithic uraniummolybdenum (U-10Mo) fuel matrix is chosen. The fuel element design is changed from 15-plate finned HEU fuel to 19-plate unfinned LEU fuel with the same geometry. The reactor power increases from 6.0 MW to 7.0 MW thermal, and primary coolant flow rate increases from 2000 gpm to 2400 gpm. Detailed analyses were completed for initial LEU core with 22 fuel elements, and demonstrated both neutronic and thermal hydraulic safety requirements are met throughout equilibrium cycles. An alternative conversion strategy is proposed which involves a gradual transition from an all-HEU core to an all-LEU core by replacing 3 HEU fuel elements with fresh LEU fuel elements during each fuel cycle. The objectives of this study are to demonstrate that the primary coolant system can be safely modified for 2400 gpm operation, and to perform steady-state and loss-of-flow (LOF) transient thermal-hydraulic analyses for the MITR HEU-LEU transitional mixed cores to evaluate this alternative conversion strategy. The primary technical challenge for the 20% increase in primary flow rate with existing piping system is flow-induced vibration. Several experiments were performed to measure and quantify vibration acceleration and velocity on three main hydraulic components to determine if higher flowrates cause excessive vibration. The test results show that the maximum vibration velocity is 9.70 mm/s, the maximum vibration acceleration is 0.98 G at the current flow rate 2000 gpm and no significant spectral change in the vibration profile at 2550 gpm. Therefore, it can be concluded that the existing piping system can safely support 2400 gpm primary flow operation. Thermal hydraulics analysis was performed using RELAP5 MOD3.3 code and STAT7 code. The MITR transitional mixed core input models were constructed to simulate the reactor primary system. Two scenarios, steady-state and loss-of-flow transient were simulated at power level of 6 MW. RELAP5 results show that during steady state, there is significant safety margin ( 10 °C) to onset of nucleate boiling for both HEU and LEU fuel. The maximum core temperature occurs at HEU fuel in Mix-core 3, the maximum wall temperature reached was 89 °C. During the LOF transient case, the result shows that The HEU fuel element is more limiting than the LEU in transitional cores. Nucleate boiling is predicted to occur only in the HEU hot channel during the first 50 seconds after the pump coastdown. The peak cladding temperatures are much lower than the fuel temperature safety limit of UAl[subscript x] fuel plates, which is 450 °C. From the STAT7 calculation results, the operational limiting power at which onset of nucleate boiling (ONB) occurs in all cases show significant margins from the Limiting System Safety Setting (LSSS) over-power level. The lowest margin for LEU element during the mixed core transition is at Mix-7, 11.43 MW with a 4.03 MW power margin. For the HEU element, the lowest margin during the transition is at Mix-2, 8.51 MW with a 1.11 MW power margin. The location at which ONB is always expected to occur is F-Plate Stripe 1 and 4 for the LEU fuel element; side plate for the HEU fuel element with the HEU element is always more limiting.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Progress Challenges and Opportunities for Converting U S and Russian Research Reactors written by Russian Academy of Sciences and published by National Academies Press. This book was released on 2012-03-24 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highly enriched uranium (HEU) is used for two major civilian purposes: as fuel for research reactors and as targets for medical isotope production. This material can be dangerous in the wrong hands. Stolen or diverted HEU can be used-in conjunction with some knowledge of physics-to build nuclear explosive devices. Thus, the continued civilian use of HEU is of concern particularly because this material may not be uniformly well-protected. To address these concerns, the National Research Council (NRC) of the U.S. National Academies and the Russian Academy of Sciences (RAS) held a joint symposium on June 8-10, 2011. Progress, Challenges, and Opportunities for Converting U.S. and Russian Research Reactors summarizes the proceedings of this joint symposium. This report addresses: (1) recent progress on conversion of research reactors, with a focus on U.S.- and R.F.-origin reactors; (2) lessons learned for overcoming conversion challenges, increasing the effectiveness of research reactor use, and enabling new reactor missions; (3) future research reactor conversion plans, challenges, and opportunities; and (4) actions that could be taken by U.S. and Russian organizations to promote conversion. The agenda for the symposium is provided in Appendix A, biographical sketches of the committee members are provided in Appendix B, and the report concludes with the statement of task in Appendix C.
Download or read book Evaluation of the Thermal hydraulic Operating Limits of the HEU LEU Transition Cores for the MIT Research Reactor written by Yunzhi Diana Wang and published by . This book was released on 2009 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MIT Research Reactor (MITR) is in the process of conducting a design study to convert from High Enrichment Uranium (HEU) fuel to Low Enrichment Uranium (LEU) fuel. The currently selected LEU fuel design contains 18 plates per element, compared to the existing HEU design of 15 plates per element. A transitional conversion strategy, which consists of replacing three HEU elements with fresh LEU fuel elements in each fuel cycle, is proposed. The objective of this thesis is to analyze the thermo-hydraulic safety margins and to determine the operating power limits of the MITR for each mixed core configuration. The analysis was performed using PLTEMP/ANL ver 3.5, a program that was developed for thermo-hydraulic calculations of research reactors. Two correlations were used to model the friction pressure drop and enhanced heat transfer of the finned fuel plates: the Carnavos correlation for friction factor and heat transfer, and the Wong Correlation for friction factor with a constant heat transfer enhancement factor of 1.9. With these correlations, the minimum onset of nucleate boiling (ONB) margins of the hottest fuel plates were evaluated in nine different core configurations, the HEU core, the LEU core and seven mixed cores that consist of both HEU and LEU elements. The maximum radial power peaking factors were assumed at 2.0 for HEU and 1.76 for LEU in all the analyzed core configurations. The calculated results indicate that the HEU fuel elements yielded lower ONB margins than LEU fuel elements in all mixed core configurations. In addition to full coolant channels, side channels next to the support plates that form side coolant channels were analyzed and found to be more limiting due to higher flow resistance. The maximum operating powers during the HEU to LEU transition were determined by maintaining the minimum ONB margin corresponding to the homogeneous HEU core at 6 MW. The recommended steady-state power is 5.8 MW for all transitional cores if the maximum radial peaking is adjacent to a full coolant channel and 4.9 MW if the maximum radial peaking is adjacent to a side coolant channel.
Download or read book Reducing the Use of Highly Enriched Uranium in Civilian Research Reactors written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2016-02-12 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: The continued presence of highly enriched uranium (HEU) in civilian installations such as research reactors poses a threat to national and international security. Minimization, and ultimately elimination, of HEU in civilian research reactors worldwide has been a goal of U.S. policy and programs since 1978. Today, 74 civilian research reactors around the world, including 8 in the United States, use or are planning to use HEU fuel. Since the last National Academies of Sciences, Engineering, and Medicine report on this topic in 2009, 28 reactors have been either shut down or converted from HEU to low enriched uranium fuel. Despite this progress, the large number of remaining HEU-fueled reactors demonstrates that an HEU minimization program continues to be needed on a worldwide scale. Reducing the Use of Highly Enriched Uranium in Civilian Research Reactors assesses the status of and progress toward eliminating the worldwide use of HEU fuel in civilian research and test reactors.
Download or read book INIS Atomindeks written by and published by . This book was released on 1987 with total page 1362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1985 with total page 1026 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reducing the Use of Highly Enriched Uranium in Civilian Research Reactors written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2016-03-12 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: The continued presence of highly enriched uranium (HEU) in civilian installations such as research reactors poses a threat to national and international security. Minimization, and ultimately elimination, of HEU in civilian research reactors worldwide has been a goal of U.S. policy and programs since 1978. Today, 74 civilian research reactors around the world, including 8 in the United States, use or are planning to use HEU fuel. Since the last National Academies of Sciences, Engineering, and Medicine report on this topic in 2009, 28 reactors have been either shut down or converted from HEU to low enriched uranium fuel. Despite this progress, the large number of remaining HEU-fueled reactors demonstrates that an HEU minimization program continues to be needed on a worldwide scale. Reducing the Use of Highly Enriched Uranium in Civilian Research Reactors assesses the status of and progress toward eliminating the worldwide use of HEU fuel in civilian research and test reactors.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1994 with total page 1688 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dismantling the Bomb and Managing the Nuclear Materials written by États-Unis. Congress. Office of Technology Assessment and published by DIANE Publishing. This book was released on 1993 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Actinoid Series Elements Advances in Research and Application 2012 Edition written by and published by ScholarlyEditions. This book was released on 2012-12-26 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Actinoid Series Elements—Advances in Research and Application: 2012 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Actinoid Series Elements. The editors have built Actinoid Series Elements—Advances in Research and Application: 2012 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Actinoid Series Elements in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Actinoid Series Elements—Advances in Research and Application: 2012 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Proceedings of the 1988 International Meeting on Reduced Enrichment for Research and Test Reactors San Diego California September 19 22 1988 written by and published by . This book was released on 1993 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neutronics and Thermal Hydraulics Study for Using a Low Enriched Uranium Core in the Advanced Test Reactor 2008 Final Report written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced Test Reactor (ATR) is a high power density and high neutron flux research reactor operating in the United States. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth. Because of the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting an HEU driven reactor to a low-enriched core. The present work investigates the necessary modifications and evaluates the subsequent operating effects of this conversion. A detailed plate-by-plate MCNP ATR 1/8th core model was developed and validated for a fuel cycle burnup comparison analysis. Using the current HEU U 235 enrichment of 93.0 % as a baseline, an analysis was performed to determine the low-enriched uranium (LEU) density and U-235 enrichment required in the fuel meat to yield an equivalent K-eff versus effective full power days (EFPDs) between the HEU and the LEU cores. The MCNP ATR 1/8th core model was used to optimize the U 235 loading in the LEU core, such that the differences in K-eff and heat flux profiles between the HEU and LEU cores were minimized. The depletion methodology MCWO was used to calculate K-eff versus EFPDs in this paper. The MCWO-calculated results for the LEU demonstrated adequate excess reactivity such that the K-eff versus EFPDs plot is similar to the ATR reference HEU case study. Each HEU fuel element contains 19 fuel plates with a fuel meat thickness of 0.508 mm (20 mil). In this work, the proposed LEU (U-10Mo) core conversion case with nominal fuel meat thickness of 0.330 mm (13 mil) and U-235 enrichment of 19.7 wt% is used to optimize the radial heat flux profile by varying the fuel meat thickness from 0.191 mm (7.0 mil) to 0.330 mm (13.0 mil) at the inner 4 fuel plates (1-4) and outer 4 fuel plates (16-19). A 0.8g of Boron-10, a burnable absorber, was added in the inner and outer plates to reduce the initial excess reactivity, and the peak to average ratio of the inner/outer heat flux more effectively. Because the B-10 (n, a) reaction will produce Helium-4 (He-4), which might degrade the LEU foil type fuel performance, an alternative absorber option is proposed. The proposed LEU case study will have 6.918 g of Cadmium (Cd) mixed with the LEU at the inner 4 fuel plates (1-4) and outer 4 fuel plates (16-19) as a burnable absorber to achieve peak to average ratios similar to those for the ATR reference HEU case study.
Download or read book RRFM 97 written by and published by . This book was released on 1997 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 1992 International Meeting on Reduced Enrichment for Research and Test Reactors Roskilde Denmark September 27 October 1 1992 written by Karsten Haack and published by . This book was released on 1993 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Science Abstracts written by and published by . This book was released on 1995 with total page 1990 pages. Available in PDF, EPUB and Kindle. Book excerpt:
