scholarly journals The Development of Mobile Melt-Dilute Technology for the Treatment of Former Soviet Union Research Reactor Fuel

2004 ◽  
Author(s):  
D. A. Sell ◽  
E. A. Howden ◽  
K. J. Allen ◽  
K. Marsden ◽  
B. R. Westphal ◽  
...  
Keyword(s):  
Soviet Union ◽  
Former Soviet Union ◽  
Research Reactor ◽  
Melting Process ◽  
Reactor Fuel ◽  
United States Government ◽  
Spent Fuel ◽  
Gas Treatment ◽  
Research Reactors ◽  
Enriched Uranium

United States Government funded national security nuclear non-proliferation projects have historically focused on power reactor spent fuel assemblies that contain weapons usable materials. More recently concern and emphasis have been focused on the spent fuel located at the many research reactor facilities spread throughout the Former Soviet Union. The need exists for a mobile system that can be deployed at these research reactors for the purpose of ensuring that the nuclear materials cannot be used for weapons development. On-site application of the Mobile Melt-Dilute (MMD) process offers an economical method for converting weapons usable Former Soviet Union high enriched uranium research reactor fuel to a safe and secure low enriched uranium ingot. The process will generate little waste and will be performed in a sealed canister that will contain all off-gas products generated during the melting process, eliminating the need for an off-gas treatment system. The process is modular, reusable, and readily portable to a desired reactor site or storage location. The storage canisters containing the melted ingot can be configured for compatibility with the fuel storage technologies currently available or returned to Russia for reprocessing under the Russian Research Reactor Fuel Return Program. The objective of the MMD Project is to develop the mobile melt and dilute technology in preparation for active deployment at Russian built and fueled research reactors. The project has just completed conceptual design and is beginning proof of principle experiments and integrated prototype design of the furnace and canister.

scholarly journals Material Matters

MRS Bulletin ◽  
1998 ◽  
Vol 23 (3) ◽  
pp. 6-16 ◽  
Author(s):  
W. Stoll
Keyword(s):  
Soviet Union ◽  
Former Soviet Union ◽  
Nuclear Power ◽  
The United States ◽  
Weapons Of Mass Destruction ◽  
Spent Fuel ◽  
Power Stations ◽  
The Soviet Union ◽  
Water Reactors ◽  
Enriched Uranium

The following article is based on a talk for Symposium X presented by Wolfgang Stoll, Chief Scientific Advisor and Consultant in Siemens, Germany, at the 1996 MRS Fall Meeting.Since 1941 when Glenn Seaborg first isolated plutonium in milligram quantities, the total amount converted through neutron capture in U-238 has increased worldwide to about 1,200 tons and continues to grow about 70 tons/year. What was fissioned in situ in operating nuclear power stations is roughly equivalent to 5 billion tons of black coal, while the fission energy contained in those 1,200 tons unloaded in spent fuel is equivalent to another 2 billion tons of coal. About 260 of these 1,200 tons are ready to release their energy in about 4 kg-portions each in microseconds which is equivalent to 10,000 tons of coal. Most people believe this release of energy poses a major threat of the worldwide arsenal of weapons of mass destruction (WMD). The about 20-fold overkill stored in worldwide WMD is considered superfluous after the crumbling of the Soviet Union. Options are sought to dispose of this surplus in a safe, speedy, and controllable manner. While for highly enriched uranium (HEU) (the other nuclear weapons material) dilution into low-enriched uranium and utilization in current light water reactors (LWR) poses market adaptation problems only, and while the worldwide consensus on the elimination of chemical and biological WMD is still in an initial phase, the decision of both the United States (US) and the former Soviet Union (FSU) to remove most of the plutonium out of weapons looks as if it was a firm political decision.

scholarly journals Innovative and safe supply of fuels for reactors

2020 ◽  
Vol 6 ◽  
pp. 40
Author(s):  
Stéphane Valance ◽  
Bruno Baumeister ◽  
Winfried Petry ◽  
Jan Höglund
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
High Performance ◽  
Research Reactor ◽  
Fissile Material ◽  
Nuclear Fuels ◽  
Research Reactors ◽  
Enriched Uranium ◽  
Performance Research ◽  
And Training

Within the Euratom research and training program 2014–2018, three projects aiming at securing the fuel supply for European power and research reactors have been funded. Those three projects address the potential weaknesses – supplier diversity, provision of enriched fissile material – associated with the furbishing of nuclear fuels. First, the ESSANUF project, now terminated, resulted in the design and licensing of a fuel element for VVER-440 nuclear power plant manufactured by Westinghouse. The HERACLES-CP project aimed at preparing the conversion of high performance research reactor to low enriched uranium fuels by exploring fuels based on uranium-molybdenium. Finally, the LEU-FOREvER pursues the work initiated in HERACLES-CP, completing it by an exploration of the high-density silicide fuels, and including the diversification of fuel supplier for soviet designed European medium power research reactor. This paper describes the projects goals, structure and their achievements.

scholarly journals Inverse modelling of the Chernobyl source term using atmospheric concentration and deposition measurements

2017 ◽  
Author(s):  
Nikolaos Evangeliou ◽  
Thomas Hamburger ◽  
Anne Cozic ◽  
Yves Balkanski ◽  
Andreas Stohl
Keyword(s):  
Soviet Union ◽  
Former Soviet Union ◽  
Source Term ◽  
Main Direction ◽  
Inverse Modelling ◽  
Spent Fuel ◽  
Atmospheric Concentration ◽  
The Public ◽  
The Usa ◽  
Modelling Techniques

Abstract. The present paper describes the results of an inverse modelling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the real magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modelling tools were further developed, inverse modelling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high quality measurements, that are essential for inverse modelling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations, but also deposition measurements from the most recent public dataset. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to give such kind of measurements into anyone interested. As regards to our inverse modelling results, emissions of 134Cs were estimated to be 80 PBq or 30–50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, in the same order with previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km) than previously assumed (≈ 2.2 km) in order to better match both concentration and deposition observations over Europe. The results were of the present inversion were confirmed using an independent Eulerial model, for which deposition patterns were also improved when using the estimated posterior releases. Although the independent model tends to underestimate deposition in countries that are not in the main direction of the plume, it reproduces country levels of deposition very efficiently. The results were also tested for robustness against different set-ups of the inversion through sensitivity runs. The source term data from this study are made publically available.

From High to Low Enriched Uranium Fuel in Research Reactors

2010 ◽  
Vol 73 ◽  
pp. 78-90 ◽  
Author(s):  
Sven van den Berghe ◽  
Ann Leenaers ◽  
Edgar Koonen ◽  
Leo Sannen
Keyword(s):  
Research Reactor ◽  
Current Status ◽  
Research Reactors ◽  
Dispersion Fuel ◽  
The Past ◽  
Uranium Fuel ◽  
The World ◽  
Enriched Uranium ◽  
The Moment ◽  
Global Threat

Since the 1970's, global efforts have been going on to replace the high-enriched (>90% 235U), low-density UAlx research reactor fuel with high-density, low enriched (<20% 235U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U3Si2 dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U3Si2 (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development.

The Removal, Transportation and Final Treatment and Conditioning of the THETIS Research Reactor Spent Fuel of the University of Ghent (Belgium) Achieved in 2010

2011 ◽  
Author(s):  
Hubert Thierens ◽  
Myriam Monsieurs ◽  
Vincent De pooter ◽  
Luc Noynaert ◽  
Patrick Maris ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Research Reactor ◽  
Storage Period ◽  
Disposal Site ◽  
Research Centre ◽  
Nuclear Materials ◽  
Spent Fuel ◽  
Nuclear Facilities ◽  
Enriched Uranium ◽  
Intermediate Storage

The THETIS research reactor on the site of the Nuclear Sciences Institute of the Ghent University has been in operation from 1967 until December 2003. This light-water moderated graphite-reflected low-enriched uranium pool-type reactor has been used for various purposes e.g. the production of radio-isotopes and activation analyses. During the first years its core power was 15 kW. In the early ’70, a core enlargement allowed for operation at typically 150 kW, while the maximum was allowed to be 250 kW. The fuel was 5% enriched uranium cladded with AISI304L stainless steel, with graphite plugs at both ends of the tubes. In order to decommission the reactor, the spent fuel and other nuclear materials present had to be removed from the reactor site. Ghent University entrusted SCK·CEN, the Belgian Nuclear Research Centre, with the study of the further management of the spent fuel. Various options such as reprocessing, intermediate storage awaiting final disposal were investigated. However the characteristics and the small amount of spent fuel (84.64 kg of UO2) made these solutions very expensive. In the meantime ONDRAF/NIRAS, the Belgian radioactive waste management agency, was developing together with Belgoprocess, a solution for final conditioning in 400 liter drums and further intermediate storage of the spent fuel in its nuclear facilities at the BELGOPROCESS site in Dessel. This conditioned waste is foreseen to enter the future geological disposal site after the intermediate storage period only after 2050. Finally SCK·CEN recommended this solution for the back-end of the THETIS spent fuel and Ghent University declared this spent fuel as radioactive waste. Once the feasibility for conditioning and storage was demonstrated, further actions were taken in order to unload the spent fuel out of the reactor and to transport it to the PAMELA-installation at the Belgoprocess site in Dessel. Finally after receiving all necessary licensing authorisations from the FANC/AFCN, the Belgian nuclear safety authority, the operations started at the reactor site beginning of 2010 and the spent fuel was placed into the intermediate storage building after conditioning at the Belgoprocess site at the end of 2010. The paper will focus on: - the inventarisation and characterization of the spent fuel and other nuclear materials; - the operations at Ghent University and Belgoprocess sites; - the conclusions drawn from the operations.

scholarly journals PRODUCTION OF URANIUM-MOLYBDENUM ALLOY AS A CANDIDATE FOR NUCLEAR RESEARCH REACTOR FUEL

2018 ◽  
Vol 24 (3) ◽  
Author(s):  
Ganisa Kurniati Suryaman ◽  
Muhammad Waziz Wildan ◽  
Supardjo Supardjo ◽  
Yatno Dwi Agus Susanto
Keyword(s):  
Research Reactor ◽  
Dendritic Structure ◽  
Nuclear Research ◽  
Melting Process ◽  
Reactor Fuel ◽  
Molybdenum Content ◽  
Molybdenum Alloy ◽  
Arc Melting ◽  
Examination Result ◽  
Nuclear Research Reactor

PRODUCTION OF URANIUM−MOLYBDENUM ALLOY AS A CANDIDATE FOR NUCLEAR RESEARCH REACTOR FUEL. Research and development on high density uranium for nuclear research reactor fuel is still in progress. Uranium-molybdenum alloy is one of the strongest candidates of nuclear research reactor fuel material. The properties and characteristics of U-Mo alloy is of important consideration for the selction of the fabrication techniques for the production of  the fuel. In this work, uranium-molybdenum (U-Mo) alloys with varied molybdenum content have been produced succesfully by arc melting technique. The molybdenum content variations were 7 %wt, 8 %wt, 9 %wt and 10 %wt Mo. The melting process was done 5 times to achieve homogenization. Metallographic micrograph shows the presence of dendritic structure. XRD examination result affirms the presence of 2 phases of γ-U phase and d-U2Mo phase. Microhardness Vickers test shows higher hardness value for Uranium-molybdenum alloy with higher molybdenum content.Keywords: U−Mo alloy, research reactor, fuel.

scholarly journals Interim Storage of the Dalat Nuclear Research Reactor: Radiation Safety Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Kien-Cuong Nguyen ◽  
Vinh-Vinh Le ◽  
Ton-Nghiem Huynh ◽  
Ba-Vien Luong ◽  
Nhi-Dien Nguyen ◽  
...  
Keyword(s):  
Research Reactor ◽  
Radiation Safety ◽  
Nuclear Research ◽  
Severe Case ◽  
Safety Analysis ◽  
Water Levels ◽  
Spent Fuel ◽  
Nuclear Research Reactor ◽  
Enriched Uranium ◽  
Interim Storage

Radiation safety analysis of a new interim storage of the Dalat Nuclear Research Reactor (DNRR) for keeping spent high enriched uranium (HEU) fuel bundles during the core conversion to low enriched uranium (LEU) fuel had been performed and presented. The photon source and decay heat of the spent HEU fuel bundles were calculated using the ORIGEN2.1 code. Gamma dose rates of the spent fuel interim storage were evaluated using the MCNP5 code with various scenarios of water levels in the reactor tank and cooling time. The radiation safety analysis shows that the retention of 106 spent HEU fuel bundles at the interim storage together with a core of 92 LEU fuel bundles meets the requirements of radiation safety. The results indicate that in the most severe case, i.e., the complete loss of water in the reactor tank, the operators still can access the reactor hall to mitigate the accident within a limited time. Particularly, in the control room, the dose rate of about 1.4  μ Sv / h is small enough for people to work normally.

scholarly journals Inverse modeling of the Chernobyl source term using atmospheric concentration and deposition measurements

2017 ◽  
Vol 17 (14) ◽  
pp. 8805-8824 ◽  
Author(s):  
Nikolaos Evangeliou ◽  
Thomas Hamburger ◽  
Anne Cozic ◽  
Yves Balkanski ◽  
Andreas Stohl
Keyword(s):  
Soviet Union ◽  
Inverse Modeling ◽  
Former Soviet Union ◽  
Source Term ◽  
Main Direction ◽  
Spent Fuel ◽  
Atmospheric Concentration ◽  
Modeling Tools ◽  
Data Set ◽  
Public Data

Abstract. This paper describes the results of an inverse modeling study for the determination of the source term of the radionuclides 134Cs, 137Cs and 131I released after the Chernobyl accident. The accident occurred on 26 April 1986 in the Former Soviet Union and released about 1019 Bq of radioactive materials that were transported as far away as the USA and Japan. Thereafter, several attempts to assess the magnitude of the emissions were made that were based on the knowledge of the core inventory and the levels of the spent fuel. More recently, when modeling tools were further developed, inverse modeling techniques were applied to the Chernobyl case for source term quantification. However, because radioactivity is a sensitive topic for the public and attracts a lot of attention, high-quality measurements, which are essential for inverse modeling, were not made available except for a few sparse activity concentration measurements far from the source and far from the main direction of the radioactive fallout. For the first time, we apply Bayesian inversion of the Chernobyl source term using not only activity concentrations but also deposition measurements from the most recent public data set. These observations refer to a data rescue attempt that started more than 10 years ago, with a final goal to provide available measurements to anyone interested. In regards to our inverse modeling results, emissions of 134Cs were estimated to be 80 PBq or 30–50 % higher than what was previously published. From the released amount of 134Cs, about 70 PBq were deposited all over Europe. Similar to 134Cs, emissions of 137Cs were estimated as 86 PBq, on the same order as previously reported results. Finally, 131I emissions of 1365 PBq were found, which are about 10 % less than the prior total releases. The inversion pushes the injection heights of the three radionuclides to higher altitudes (up to about 3 km) than previously assumed (≈ 2.2 km) in order to better match both concentration and deposition observations over Europe. The results of the present inversion were confirmed using an independent Eulerian model, for which deposition patterns were also improved when using the estimated posterior releases. Although the independent model tends to underestimate deposition in countries that are not in the main direction of the plume, it reproduces country levels of deposition very efficiently. The results were also tested for robustness against different setups of the inversion through sensitivity runs. The source term data from this study are publicly available.

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