The fast-neutron breeder fission reactor: safety issues in reactor design and operation

1990 ◽  
Vol 331 (1619) ◽  
pp. 409-418 ◽  
Keyword(s):  
Reactor Core ◽  
Liquid Sodium ◽  
Metallic Fuel ◽  
Safety Issues ◽  
Fission Reactor ◽  
Core Energy ◽  
Proper Design ◽  
Breeder Reactors ◽  
Uranium Plutonium ◽  
Safety Features

Today’s fast breeder reactors contain mixed uranium —plutonium oxide fuel and are cooled with liquid sodium. Their normal operational behaviour, including power transients, is similar to that of thermal reactors. The fact that the sodium density coefficient is positive is of no importance at normal operating temperatures because negative coefficients like Doppler or fuel expansion coefficients have compensating effects. Dangerous effects may arise when sodium boiling at much higher temperatures occur. It is shown that sodium boiling in most cases can be avoided by proper design of the reactor core. Energy releases associated with partial destruction of the core are discussed. The safety features of metallic fuel are briefly discussed, resulting in the statement that in principle, use of metallic fuel does not promise more positive safety features.

scholarly journals THE CORRELATION OF THE CATEGORIES OF “QUALITY” AND “SAFETY” OF PRODUCTS

2019 ◽  
pp. 74-78
Author(s):  
T.V. Malanchuk ◽  
E.A. Zaitsev
Keyword(s):  
Civil Rights ◽  
Legal Regulation ◽  
Poor Quality ◽  
Product Safety ◽  
Legal Rights ◽  
Safety Issues ◽  
State Supervision ◽  
Safety Features ◽  
And Control

The article analyzes the complex state of the modern legislative regulation of quality and product safety issues in the context of ensuring consumers’ rights to the proper quality of goods (works, services). It is stated that in view of the variety of different properties that make up the notion of quality, the most important are the defects, which are capable of damaging the life, health, or property of the consumer, that is, the defects, which indicate that the goods are dangerous. The safety of goods works, and services as a legal category are of particular importance and is one of the functions of the state to ensure public safety. State measures of influence on manufacturers and sellers of goods, persons who perform work and provide services should be aimed at ensuring the protection of fundamental civil rights. In most cases, these are imperative requirements for safety, which are approved by special legal acts, as well as measures of state supervision and control to ensure the safety of manufactured goods, works, and services. The legislator, when defining security, uses the term “safety of goods (works, services)”, but it would be advisable to carry out graduation of these concepts since the safety of goods is a state of goods that allows it to be sold, used, stored, transported, disposed of without harm for life, health, the property of the consumer and the environment in normal conditions, and the safety of works and services is the quality of protection of the legal rights of the consumer in carrying out the activities of persons who perform work and provide services, danger to life, health, the property should not manifest itself either in their implementation and providing or later. It is noted that quality requirements should be made mandatory when designing production specifications. It is stated that in order to ensure the effectiveness of legal regulation, the safety of a product, work, or service must be considered as a full-fledged property within the legal notion of quality. It is concluded that product safety is an integral feature of any product, work, and service, acting as an integral element of the quality category. Lack of safety features indicates that the product is of poor quality. Keywords: quality, safety, proper quality, improper quality, specifications, consumers.

Modeling the Spectral History in the Depletion of a PWR Core

2010 ◽  
Author(s):  
I. Bilodid
Keyword(s):  
Cross Sections ◽  
Uranium Oxide ◽  
Reactor Core ◽  
Actual Distribution ◽  
History Effects ◽  
Fuel Assemblies ◽  
Burnable Absorber ◽  
Uranium Plutonium ◽  
Moderator Density ◽  
Local Parameters

Codes for reactor core calculations use few-group cross sections (XS) which depend on local burnup, given in terms of the energy produced per fuel mass (MWd/kgHM). However, a certain burnup value can be reached under different spectral conditions depending on moderator density and other local parameters. Neglecting these spectral effects, i.e. applying the summary-burnup value only, can cause considerable errors in the calculated power density. This paper describes a way to take into account spectral-history effects. It is shown that the respective XS correction linearly depends on the actual Pu-239 concentration. The applicability of the method was proved not only for usual uranium oxide fuel, but also for mixed uranium/plutonium oxide (MOX) and fuel assemblies with burnable absorber. The code DYN3D was extended by new subroutines which calculate the actual distribution of Pu-239 in the core and apply a spectral-history correction for the XS.

Experimental Evaluation of Pool Fire Suppression Performance of Sodium Leak Collection Tray in Open Air

2006 ◽  
Author(s):  
F. C. Parida ◽  
P. M. Rao ◽  
S. S. Ramesh ◽  
B. Malarvizhi ◽  
V. Gopalakrishnan ◽  
...  
Keyword(s):  
Fire Protection ◽  
Collection Efficiency ◽  
Fire Suppression ◽  
Ambient Air ◽  
Thermal Fluctuations ◽  
Liquid Sodium ◽  
Drain Pipe ◽  
External Power Source ◽  
Oxygen Starvation ◽  
Breeder Reactors

In the event of sodium leakage from heat transfer circuits of fast breeder reactors (FBR), liquid sodium catches fire in ambient air leading to production of flame, smoke and heat. One of the passive fire protection methods involves immediate collection of the leaking sodium to a sodium hold-up vessel (SHV) covered with a sloping cover tray (SCT) having a few drain pipes and one vent pipe (as in Fig. 1). As soon as the liquid sodium falls on the sloping cover tray, gravity guides the sodium through drain pipes into the bottom tray in which self-extinction occurs due to oxygen starvation. This sodium fire protection equipment called leak collection tray (LCT) works without the intervention of an operator and external power source. A large number of LCTs are strategically arranged under the sodium circulating pipe lines in the FBR plants to serve as passive suppression devices. In order to test the efficacy of the LCT, four tests were conducted. Two tests were with LCT having three drain pipes and rest with one. In each experiment, nearly 40 kg of hot liquid sodium at 550 °C was discharged on the LCT in the open air. Continuous on-line monitoring of temperature at strategic locations (∼ 28 points) were carried out. Colour videography was employed for taking motion pictures of various time-dependent events like sodium dumping, appearance of flame and release of smoke through vent pipes. After self-extinction of sodium fire, the LCT was allowed to cool overnight in an argon atmosphere. Solid samples of sodium debris in the SCT and SHV were collected by manual core drilling machine. The samples were subjected to chemical analysis for determination of unburnt and burnt sodium. The results of the four tests revealed an interesting feature: LCT with three drain pipes showed far lower sodium collection efficiency and much higher sodium combustion than that with just one drain pipe. Thermal fluctuations in temperature sensor located near the tip of the drain pipe have indicated that transient freezing and remelting processes are responsible for this phenomenon. Moreover comparison of test results between present and earlier experiments has revealed that the LCT with funnel shaped SCT is superior to that with boat shaped SCT.

scholarly journals Neutron data field in a fission reactor core with fusion neutron source at pulse-periodic operation

2020 ◽  
Vol 1647 ◽  
pp. 012007
Author(s):  
I V Shamanin ◽  
V M Shmakov ◽  
D G Modestov ◽  
S V Bedenko ◽  
S D Polozkov ◽  
...  
Keyword(s):  
Neutron Source ◽  
Reactor Core ◽  
Periodic Operation ◽  
Neutron Data ◽  
Fusion Neutron ◽  
Fission Reactor ◽  
Fusion Neutron Source ◽  
Data Field

ASSESSMENT OF FAST-SPECTRUM BLANKET LATTICES FOR BREEDING FISSILE FUEL FROM THORIUM AND DEPLETED URANIUM IN AN EXTERNALLY DRIVEN SUB-CRITICAL GAS-COOLED PRESSURE TUBE REACTOR

2018 ◽  
Vol 7 (2) ◽  
pp. 201-220
Author(s):  
Blair Patrick Bromley ◽  
Jude Alexander
Keyword(s):  
Extended Period ◽  
Depleted Uranium ◽  
Square Lattice ◽  
Critical Systems ◽  
Fission Reactor ◽  
Thermal Spectrum ◽  
Fuel Bundle ◽  
Driven System ◽  
Breeder Reactors

To ensure long-term nuclear energy security, it is advantageous to consider the use of externally driven sub-critical systems for producing fissile fuel to supply fleets of thermal-spectrum reactors as an alternative to using fast-spectrum or thermal-spectrum breeder reactors. Computational/analytical neutronics and heat transfer studies have been carried out for gas-cooled fuel bundle lattices with mixtures of fertile thorium and depleted uranium (DU) that could be used in the blanket region of a sub-critical fast reactor driven either by a fusion reactor in a hybrid fusion-fission reactor (HFFR) system, or an accelerator-based spallation neutron source in an accelerator driven system (ADS). The HFFR or ADS concept envisioned is one with a simple cylindrical geometry. The annular-cylindrical blanket is approximately 10 m long, can be made 2–5 m thick (1.0 m ≤ Rblanket ≤ 3.0 m to 6.0 m), and is filled with a repeating square lattice of pressure tubes filled with 0.5 m long fuel bundles that are made of (DU,Th)O2, with various mixtures of Th and DU, and refuelled periodically online. Although using blankets made of pure DUO2 or ThO2 are viable options to analyze, mixing DUO2 with ThO2 can help alleviate any potential proliferation concerns, since any 233U produced from breeding will be denatured by the presence of 238U in (DU, Th)O2. Lattice calculations demonstrate that the total fissile content in the fuel after an extended period of burnup (50 MWd/kg) will be approximately the same, regardless of the mixture of DU and thorium used, and that the content of americium and 232U in the irradiated fuel will be <0.01 wt%/initial heavy metal.

Predictive Modeling of Acoustic Signals From Thermoacoustic Power Sensors (TAPS)

2016 ◽  
Author(s):  
Christopher M. Dumm ◽  
Jeffrey S. Vipperman ◽  
Jorge V. Carvajal ◽  
Melissa M. Walter ◽  
Luke Czerniak ◽  
...  
Keyword(s):  
Predictive Modeling ◽  
Acoustic Waves ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Signal Propagation ◽  
Acoustic Signals ◽  
Operating Conditions ◽  
Liquid Sodium ◽  
Thermoacoustic Engines ◽  
Self Powered

Thermoacoustic Power Sensor (TAPS) technology offers the potential for self-powered, wireless measurement of nuclear reactor core operating conditions. TAPS are based on thermoacoustic engines, which harness thermal energy from fission reactions to generate acoustic waves by virtue of gas motion through a porous stack of thermally nonconductive material. TAPS can be placed in the core, where they generate acoustic waves whose frequency and amplitude are proportional to the local temperature and radiation flux, respectively. TAPS acoustic signals are not measured directly at the TAPS; rather, they propagate wirelessly from an individual TAPS through the reactor, and ultimately to a low-power receiver network on the vessel’s exterior. In order to rely on TAPS as primary instrumentation, reactor-specific models which account for geometric/acoustic complexities in the signal propagation environment must be used to predict the amplitude and frequency of TAPS signals at receiver locations. The reactor state may then be derived by comparing receiver signals to the reference levels established by predictive modeling. In this paper, we develop and experimentally benchmark a methodology for predictive modeling of the signals generated by a TAPS system, with the intent of subsequently extending these efforts to modeling of TAPS in a liquid sodium environment.

Kinematic dynamo action in a network of screw motions; application to the core of a fast breeder reactor

1999 ◽  
Vol 382 ◽  
pp. 137-154 ◽  
Author(s):  
F. PLUNIAN ◽  
P. MARTY ◽  
A. ALEMANY
Keyword(s):  
Magnetic Field ◽  
Experimental Studies ◽  
Magnetic Reynolds Number ◽  
Liquid Sodium ◽  
Dynamo Action ◽  
Periodic Cell ◽  
The Core ◽  
Induction Equation ◽  
Breeder Reactors ◽  
Dynamo Effect

Most of the studies concerning the dynamo effect are motivated by astrophysical and geophysical applications. The dynamo effect is also the subject of some experimental studies in fast breeder reactors (FBR) for they contain liquid sodium in motion with magnetic Reynolds numbers larger than unity. In this paper, we are concerned with the flow of sodium inside the core of an FBR, characterized by a strong helicity. The sodium in the core flows through a network of vertical cylinders. In each cylinder assembly, the flow can be approximated by a smooth upwards helical motion with no-slip conditions at the boundary. As the core contains a large number of assemblies, the global flow is considered to be two-dimensionally periodic. We investigate the self-excitation of a two-dimensionally periodic magnetic field using an instability analysis of the induction equation which leads to an eigenvalue problem. Advantage is taken of the flow symmetries to reduce the size of the problem. The growth rate of the magnetic field is found as a function of the flow pitch, the magnetic Reynolds number (Rm) and the vertical magnetic wavenumber (k). An α-effect is shown to operate for moderate values of Rm, supporting a mean magnetic field. The large-Rm limit is investigated numerically. It is found that α=O(Rm−2/3), which can be explained through appropriate dynamo mechanisms. Either a smooth Ponomarenko or a Roberts type of dynamo is operating in each periodic cell, depending on k. The standard power regime of an industrial FPBR is found to be subcritical.

Feasibility of a Nuclear Reactor Dedicated to Desalination

2014 ◽  
Author(s):  
Yong Hun Jung ◽  
Yong Hoon Jeong ◽  
Jang Sik Moon
Keyword(s):  
Nuclear Reactor ◽  
Significant Loss ◽  
Safety Issues ◽  
Nuclear Heat ◽  
Thermal Desalination ◽  
Economic Analyses ◽  
Safety Features ◽  
Low Pressures ◽  
Current Energy ◽  
Target Country

The development of a small-sized nuclear heat-only plant with maximized safety features dedicated to seawater thermal desalination was proposed to address both a serious water crisis and nuclear safety issues, which continue to be perennial problems. In this study, the feasibility of a dedicated nuclear heat-only desalination system for a target country was evaluated in comparison with a target nuclear thermal desalination system. First, the target country was selected, and its current energy and desalination status was investigated. The suitable nuclear desalination options for the target country were then selected. Finally, using corresponding analysis tools, performance and economic analyses were conducted for a dedicated nuclear heat-only desalination system and the target nuclear thermal desalination system. The results of the analyses indicate that operating the small-sized nuclear heat-only plant at low pressures coupled with a seawater thermal desalination plant will considerably improve both the safety and economy without a significant loss in desalination performance. In conclusion, the proposed dedicated nuclear heat-only desalination system is expected to have high potential for solving both problems.

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