Fuel elements based on spherical fuel pellets with a protective coating for enhanced-safety reactors

Chernikov, A. S.; Permyakov, L. N.; Fedik, I. I.; Gavrilin, S. S.; Kurbakov, S. D.

doi:10.1007/bf02673541

At Energy

1999

DOI: 10.1007/bf02673541

|View full text |Cite

Fuel elements based on spherical fuel pellets with a protective coating for enhanced-safety reactors

A. S. Chernikov¹,

L. N. Permyakov²,

I. I. Fedik³

et al.

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...

Citation Types

Supporting

Mentioning

Contrasting

Year Published

2004

2018

Publication Types

Select...

Article5

Relationship

Self Cite1

Independent4

Authors

Journals

Cited by 12 publications

(1 citation statement)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In rod and tubular fuel elements with cermet fuel, the volume content of the fuel was increased to 0.7, which is made possible by the technology developed at the Research Institute of the Luch Scientific-Industrial Association [10,11]. To implement this technology, the fuel elements differ from those the conventional ceramic fuel as follows:…”

mentioning

confidence: 99%

Direct-Flow Channel Reactor with Supercritical Coolant Pressure

et al. 2005

Self Cite

View full text Add to dashboard Cite

The concept of a direct-flow channel reactor with supercritical-pressure water (CR-SCP) is presented. Neutron-physics, thermohydraulic, and strength calculations are used to substantiate the fundamental core design with a heavy-metal moderator which at supercritical pressure is competitive with other modern reactor designs with respect to fuel-cycle indicators. Two types of fuel-element and fuel-channel structures are examined. It is shown that fuel elements based on micropellets and a metal matrix are highly reliable and have higher operating characteristics (burnup, service life, geometric stability, and so on) than fuel elements with uranium-dioxide fuel. A CR-SCP design and the technological scheme of a power-generating unit are presented, and the systems which are required to ensure normal operation and safety are determined. The main technical-economic indicators of a power-generating unit with installed electric power 850 MW are estimated.The interest in supercritical coolant pressure in reactors is due to the fact the new reactors must be competitive. In the last few years a surge of interest has been observed in Japan, USA, Germany, France, Canada, and other countries [1]. Reactors with supercritical-pressure water are being considered as one direction in the international program for the development of fourth-generation reactors.Some countries are undertaking efforts to develop direct-flow water-moderated water-cooled vessel reactors with supercritical-coolant pressure. The core of these reactors can be designed to operate on thermal and fast neutrons with almost the same thermal layouts of the power-generating units and the same efficiency. It is important to note that a fast-neutron reactor makes it possible, aside from appreciably decreasing the capital costs, to improve fuel utilization [2], since it makes it possible to increase the breeding ratio of nuclear fuel up to 1 and aim at a closed fuel cycle. However, such reactors are characterized by a change in water density by a factor of 10 from the core entrance to the core exit. This is accompanied by a change in the neutron spectrum over the height of the core and makes it difficult to smooth and stabilize the energy-release fields not only

show abstract

mentioning

confidence: 99%

Direct-Flow Channel Reactor with Supercritical Coolant Pressure

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

Evolution of defects in micropellet fuel during the fabrication of HTGR compacts

Isakov¹,

Konoplev²

2005

At Energy

View full text Add to dashboard Cite

The stress distribution arising in micropellets and cylindrical fuel compacts during fabrication, the stress concentration in micropellets located near the surface of a compact, and the evolution of defects in micropellets as a function of the type of stress state are investigated. It has been found that an ensemble of micropellets with a large number of particles contains a continuous spectrum of defects in the range 10 -4 -10 2 µm. Mechanical stresses engender evolution of the defects according to the scheme accumulation of microdefects → microcracks → cracks → through defects. Recommendations are formulated for lowering the number of defects in micropellets during deposition of coatings on the micropellets and compaction.The process of obtaining uranium-graphite fuel elements (spherical, prismatic, cylindrical) for HTGR includes the operations of depositing pyrolytic carbon (PyC) and silicon carbide (SiC) coatings on fuel kernels in the fluidized-bed furnace, mixing the obtained micropellets with graphite and a binding agent, pressing the conpacts, polymerizing the binder, carbonization and high-temperature heat-treatment [1]. The samples were pressed under pressure 10 MPa at temperature 100°C, and then went through at a higher temperature a stage of polymerization of the binder (130-160°C), carbonization (200-800°C), and high-temperature heat treatment to remove the impurities (1800°C). Most technological operations involve cycles of heating and cooling of the micropellets and compacts. As a result of the low relaxational properties of pyrolytic carbon, graphite, and silicon carbide, residual stresses arise in the micropellets and compacts after each heat-treatment cycle [2]. In the present work, the distribution of stresses arising during fabrication of micropellets and cylindrical fuel compacts, the concentration of stresses in the micropellets located near the surface of a compact, and the evolution of defects in micropellet claddings were studied as a function of the type and level of the stress state.Calculation of the Stresses in a Matrix and the Micropellets of a Compact. The growth of SiC and dense PyC coatings on the curvilinear surface of micropellets with a PyC buffer layer deposited on the pellets is accompanied by stress localization on intergrain boundaries. The average grain size is 1-3 µm for PyC and 3-5 µm for SiC [3]. Intergrain stress relaxation occurs by a dislocation mechanism.Accumulations of microdefects cannot form microcracks under the conditions of isotropic compression if the stresses do not exceed the strength limit of the material σ B . At the same time, microcracks will form if the diagonal terms of the stress tensor differ in absolute value and sign. Under these conditions, a microcrack grows in length by the Griffith mechanism [4]:σ~ l -1/2 , where σ is the stress required for a crack of length l to grow. A crack can also grow by this mechanism if σ < σ B .

show abstract

Neutronic properties of high-temperature gas-cooled reactors with thorium fuel

Shamanin

Grachev

Chertkov

et al. 2018

Annals of Nuclear Energy

View full text Add to dashboard Cite

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

customersupport@researchsolutions.com

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Fuel elements based on spherical fuel pellets with a protective coating for enhanced-safety reactors

Cited by 12 publications

References 4 publications

Direct-Flow Channel Reactor with Supercritical Coolant Pressure

Direct-Flow Channel Reactor with Supercritical Coolant Pressure

Evolution of defects in micropellet fuel during the fabrication of HTGR compacts

Neutronic properties of high-temperature gas-cooled reactors with thorium fuel

Contact Info

Product

Resources

About