scholarly journals Study of natural uranium fuel for a new reactor design TEPLATOR

2021 ◽  
Vol 253 ◽  
pp. 07012
Author(s):  
Tomas Peltan ◽  
Eva Vilimova ◽  
Radek Skoda

The TEPLATOR is a new type of nuclear reactor which the main purpose is producing heat for district heating. It is designed as a special thermal reactor with 55 fuel channels for fuel assemblies, which is moderated and cooled by heavy water and operated around atmospheric pressure. The TEPLATOR DEMO is designed for the use of irradiated fuel from PWR or BWR reactors. Using heavy water as the moderator and coolant in this reactor concept allows to use natural uranium as an alternative fuel in case that the irradiated fuel is not available for some reason. This solution is suitable because of the price of natural uranium and the absence of costly fuel enrichment. This article is focused on deeper analyses of alternative suitable fuel for TEPLATOR based on natural uranium and new fuel geometries. This work builds on previous research on alternative fuel material and geometry for the TEPLATOR. It is mainly concerned with the neutronic development of fuel assemblies, the possibility of manufacturing of developed fuel types, and optimization of fuel management and uranium consumption. This article contains predetermined candidates for suitable fuel geometries and new untested fuel geometry types with some new advantages. Finally, optimization of the whole reactor core and number of fuel channels was made in terms of increased safety and higher fuel burn-up. Presented calculations were performed by Monte Carlo code Seprent.

2020 ◽  
Vol 225 ◽  
pp. 03007
Author(s):  
Tanja Goričanec ◽  
Domen Kotnik ◽  
Žiga Štancar ◽  
Luka Snoj ◽  
Marjan Kromar

An approach for calculating ex-core detector response using Monte Carlo code MCNP was developed. As a first step towards ex-core detector response prediction a detailed MCNP model of the reactor core was made. A script called McCord was developed as a link between deterministic program package CORD-2 and Monte Carlo code MCNP. It automatically generates an MCNP input from the CORD-2 data. A detailed MCNP core model was used to calculate 3D power distributions inside the core. Calculated power distributions were verified by comparison to the CORD-2 calculations, which is currently used for core design calculation verification of the Krško nuclea power plant. For the hot zero power configuration, the deviations are within 3 % for majority of fuel assemblies and slightly higher for fuel assemblies located at the core periphery. The computational model was further verified by comparing the calculated control rod worth to the CORD-2 results. The deviations were within 50 pcm and considered acceptable. The research will in future be supplemented with the in-core and ex-core detector signal calculations and neutron transport outside the reactor core.


2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Linrong Ye ◽  
Mingjun Wang ◽  
Xin’an Wang ◽  
Jian Deng ◽  
Yan Xiang ◽  
...  

The thermal hydraulic and neutronics coupling analysis is an important part of the high-fidelity simulation for nuclear reactor core. In this paper, a thermal hydraulic and neutronics coupling method was proposed for the plate type fuel reactor core based on the Fluent and Monte Carlo code. The coupling interface module was developed using the User Defined Function (UDF) in Fluent. The three-dimensional thermal hydraulic model and reactor core physics model were established using Fluent and Monte Carlo code for a typical plate type fuel assembly, respectively. Then, the thermal hydraulic and neutronics coupling analysis was performed using the developed coupling code. The simulation results with coupling and noncoupling analysis methods were compared to demonstrate the feasibility of coupling code, and it shows that the accuracy of the proposed coupling method is higher than that of the traditional method. Finally, the fuel assembly blockage accident was studied based on the coupling code. Under the inlet 30% blocked conditions, the maximum coolant temperature would increase around 20°C, while the maximum fuel temperature rises about 30°C. The developed coupling method provides an effective way for the plate type fuel reactor core high-fidelity analysis.


2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Jawad Haroon ◽  
Leslie Kicka ◽  
Subhramanyu Mohapatra ◽  
Eleodor Nichita ◽  
Peter Schwanke

Deterministic and Monte Carlo methods are regularly employed to conduct lattice calculations. Monte Carlo methods can effectively model a large range of complex geometries and, compared to deterministic methods, they have the major advantage of reducing systematic errors and are computationally effective when integral quantities such as effective multiplication factor or reactivity are calculated. In contrast, deterministic methods do introduce discretization approximations but usually require shorter computation times than Monte Carlo methods when detailed flux and reaction-rate solutions are sought. This work compares the results of the deterministic code DRAGON to the Monte Carlo code Serpent in the calculation of the reactivity effects for a pressurized heavy water reactor (PHWR) lattice cell containing a 37-element, natural uranium fuel bundle with heavy water coolant and moderator. The reactivity effects are determined for changes to the coolant, moderator, and fuel temperatures and to the coolant and moderator densities for zero-burnup, mid-burnup [3750  MWd/t(U)] and discharge burnup [7500  MWd/t(U)] fuel. It is found that the overall trend in the reactivity effects calculated using DRAGON match those calculated using Serpent for the burnup cases considered. However, differences that exceed the amount attributable to statistical error have been found for some reactivity effects, particularly for perturbations to coolant and moderator density and fuel temperature.


Author(s):  
Robert Pool

During the 1940s and early 1950s, when atomic energy was new, it was common to hear reactors described as nuclear “furnaces.” They “burned” their nuclear fuel and left behind nuclear “ash.” Technically, of course, none of these terms made sense, since burning is a chemical process and a reactor gets its energy from fission, but journalists liked the terminology because it was easy and quick. One loaded fuel into the reactor, flipped a switch, and things got very hot. If that wasn’t exactly a furnace, it was close enough. And actually, the metaphor was pretty good—up to a point. The basement furnace burns one of several different fuels: natural gas or fuel oil or even, in some ancient models, coal. Nuclear reactors can be built to use plutonium, natural uranium, or uranium that has been enriched to varying degrees. Home furnaces have a “coolant”—the air that is circulated through the furnace and out through the rest of the house, carrying heat away from the fire. Reactors have a coolant, too—the liquid or gas that carries heat away from the reactor core to another part of the plant, where heat energy is transformed into electrical energy. There, however, the metaphor sputters out. In a nuclear reactor, the coolant not only transfers heat to a steam generator or a turbine, but it also keeps the fuel from overheating. The coolant in a furnace does nothing of the sort. And most reactors use a moderator to speed up the fission reaction. The basement burner has nothing similar. But the most importance weakness of the furnace metaphor is that it obscured just how many varieties of reactors were possible—and, consequently, obscured the difficult choice facing the early nuclear industry: Which reactor type should become the basis for commercial nuclear power? The possibilities were practically unlimited. The fuel selection was wide. The coolant could be nearly anything that has good heat-transfer properties: air, carbon dioxide, helium, water, liquid metals, organic liquids, and so on.


Author(s):  
Nineta Balas (Ghizdeanu) ◽  
Petre Ghitescu

PHWRs use natural uranium as fuel and consequently the burn-up coefficient is relatively small compared to PWRs or other existing power reactors. The small burn-up coefficient results in a high volume of irradiated fuel to be disposed, with a high concentration of plutonium and minor actinides. In Romania the irradiated fuel from the existing CANDU 6 spent fuel pool is currently transferred in the Dry Intermediate Fuel Storage Facility existing at the NPP site. Partitioning and Transmutation (P&T) techniques could contribute to reduce the radioactive inventory and its associated radio-toxicity. The use for this purpose of ADS and FBR was more studied, but HWR were not. Therefore, the paper presents different theoretical possibilities to transmute/burn the Plutonium and minor actinides in two different PHWRs — CANDU and ACR, using WIMSD code. Different types of MOX alternative fuel, with variable initial Pu content are analyzed. The results present the reactivity effects along with the isotopes concentration in spent alternative fuel and determine the optimal solution for the fuel type/composition. Thus is indicated the most suitable PHWR type of reactor for possible Plutonium and minor actinides transmutation. The simulations showed that Pu content for an irradiation period of 200 days decreases from the initial value up to 11% in a CANDU reactor and 29% in an ACR. Thus ACR can reduce the plutonium inventory from MOX fuel and could be a transmutation solution. From the economic/technical point of view this analysis also provides input for a study yet to be conducted.


Author(s):  
Frank Yee ◽  
Sermet Kuran ◽  
Mike Soulard ◽  
Zhenhua Zhang

Candu Energy, based on its highly successful CANDU 6 (C6) reactors proven on four continents, is preparing to launch its C6 referenced Generation III products: Enhanced CANDU 6 (EC6), the natural uranium optimized, and Advanced Fuel CANDU Reactor (AFCR), the alternative fuel optimized, CANDU reactors. The AFCR design is based on the EC6 design with appropriate design changes to the reactor core to cater for the alternative fuel cycles and post Fukushima improvement.. The paper reviews the common design basis of these reactors and then discusses the unique advantages and market specific features for each product. The AFCR implementation plan for China is also discussed.


2003 ◽  
Vol 125 (04) ◽  
pp. 46-48
Author(s):  
Harry Hutchinson

This article reviews that after a half century of safety testing for the nuclear industry, a key heat-transfer lab is losing its home. Columbia University’s Heat Transfer Research Facility has been the only place to go for key safety testing. Since the days of the Atoms for Peace program during the Eisenhower years, the lab has tested generations of nuclear reactor fuel assemblies. The lab’s clients over the years have included all the designers of pressurized water reactors in the United States and others from much of the world. The tests are primarily concerned with one small, but significant feature of a reactor core. A core contains as many as 3000 fuel assemblies, bundles of long, slender rods containing enriched uranium. Controlled fission among the bundles heats water to begin the series of heat-transfer cycles that send steam to the turbines that will drive generators.


2012 ◽  
Vol 27 (1) ◽  
pp. 75-83
Author(s):  
Milan Pesic

In 1958, the experimental RB reactor was designed as a heavy water critical assembly with natural uranium metal rods. It was the first nuclear fission critical facility at the Boris Kidric (now Vinca) Institute of Nuclear Sciences in the former Yugoslavia. The first non-reflected, unshielded core was assembled in an aluminium tank, at a distance of around 4 m from all adjacent surfaces, so as to achieve as low as possible neutron back reflection to the core. The 2% enriched uranium metal and 80% enriched uranium dioxide (dispersed in aluminum) fuel elements (known as slugs) were obtained from the USSR in 1960 and 1976, respectively. The so-called ?clean? cores of the RB reactor were assembled from a single type of fuel elements. The ?mixed? cores of the RB reactor, assembled from two or three types of different fuel elements, were also positioned in heavy water. Both types of cores can be composed as square lattices with different pitches, covering a range of 7 cm to 24 cm. A radial heavy water reflector of various thicknesses usually surrounds the cores. Up to 2006, four sets of clean cores (44 core configurations) have been accepted as criticality benchmarks and included into the OECD ICSBEP Handbook. The RB mixed core 39/1978 was made of 31 natural uranium metal rods positioned in heavy water, in a lattice with a pitch of 8?2 cm and 78


Author(s):  
Koichi Kitamura ◽  
Kazuya Sano ◽  
Yasuyuki Nakamura ◽  
Akira Matsushima ◽  
Hidehiko Matsuo ◽  
...  

The decommissioning program of proto-type Advanced Thermal Reactor (ATR) FUGEN has started in 2008 as first decommissioning of the commercial-scale water reactor. It consists of four periods, considering the transportation of spent fuels and the radioactive decrease of highly activated materials. It is expected that the whole program of decommissioning will be completed until 2028. Now, the decommissioning is under the first period, spent fuels and heavy water has been carrying out from FUGEN, and a part of the turbine system with relatively low radioactive contamination has been dismantled. FUGEN has a complicated core structure consisting 224 fuel channels with pressure tubes and calandria tank, etc. and used heavy water as moderator, unlike other light water reactor (LWR). The materials of the core structure were highly activated due to a long term operation, tritium and C-14 were generated, and the facilities were contaminated by them. Thus, it is important to study the dismantling technology of the reactor core and the decontamination technology, considering characteristics of FUGEN such as core structure and radioactive inventory in advance. In this presentation, the contents of the decommissioning program and its current status such as dismantling work of a part of the turbine system, the studying situation of dismantling technology of reactor core using Abrasive Water Jet (AWJ) which is a candidate of cutting technologies, the examination of tritium decontamination in heavy water system, the study of decontamination technology for C-14 will be presented mainly.


Sign in / Sign up

Export Citation Format

Share Document