Effect of the migration of fission products on measurements of burnup in fuel elements

1967 ◽  
Vol 23 (2) ◽  
pp. 817-818
Author(s):  
O. A. Miller ◽  
A. M. Demidov ◽  
B. S. Galakhmatova
Keyword(s):  
Fission Products ◽  
Fuel Elements

scholarly journals Features of methods for monitoring the fuel cladding tightness in lead-cooled fast breeder reactors

2021 ◽  
Vol 7 (4) ◽  
pp. 319-325
Author(s):  
Anastasiya V. Dragunova ◽  
Mikhail S. Morkin ◽  
Vladimir V. Perevezentsev
Keyword(s):  
Liquid Metal ◽  
Fission Products ◽  
General Description ◽  
Fuel Cladding ◽  
Reactor Plant ◽  
Reactor Unit ◽  
Basic Principles ◽  
Gaseous Fission ◽  
Breeder Reactors ◽  
Fuel Elements

To timely detect failed fuel elements, a reactor plant should be equipped with a fuel cladding tightness monitoring system (FCTMS). In reactors using a heavy liquid-metal coolant (HLMC), the most efficient way to monitor the fuel cladding tightness is by detecting gaseous fission products (GFP). The article describes the basic principles of constructing a FCTMS in liquid-metal-cooled reactors based on the detection of fission products and delayed neutrons. It is noted that in a reactor plant using a HLMC the fuel cladding tightness is the most efficiently monitored by detecting GFPs. The authors analyze various aspects of the behavior of fission products in a liquid-metal-cooled reactor, such as the movement of GFPs in dissolved and bubble form along the circuit, the sorption of volatile FPs in the lead coolant (LC) and on the surfaces of structural elements, degassing of the GFPs dissolved in the LC, and filtration of cover gas from aerosol particles of different nature. In addition, a general description is given of the conditions for the transfer of GFPs in a LC environment of the reactor being developed. Finally, a mathematical model is presented that makes it possible to determine the calculated activity of reference radionuclides in each reactor unit at any time after the fuel element tightness failure. Based on this model, methods for monitoring the fuel cladding tightness by the gas activity in the gas volumes of the reactor plant will be proposed.

Post Irradiation Testing of High Temperature Reactor Spherical Fuel Elements Under Accident Conditions

2008 ◽  
Author(s):  
D. Freis ◽  
D. Bottomley ◽  
J. Ejton ◽  
W. de Weerd ◽  
H. Kostecka ◽  
...  
Keyword(s):  
High Temperature ◽  
Fission Products ◽  
General Concept ◽  
Cold Finger ◽  
Fission Gas ◽  
Accident Condition ◽  
Gas Measurement ◽  
High Temperature Reactor ◽  
Accident Conditions ◽  
Fuel Elements

A new furnace for accident condition testing of spherical High Temperature Reactor (HTR) fuel elements has been installed and is now operating in the Hot Cells of the Institute for Transuranium Elements (ITU) Karlsruhe. The recent apparatus was constructed on the basis of a former development by Forschungszentrum Ju¨lich (FzJ) [Schenk 1988] where it was named Ku¨FA, the German acronym for cold finger apparatus. In a preceding publication [Toscano 2004] the general concept and details of the device were described. The present paper reports on the first operation under hot conditions, the calibration of the fission gas measurement and of the efficiency of the cold finger, which is used to plate out solid fission products. Finally the results of fission product release and analysis of two heating tests on two fuel elements from the HFR K6 irradiation experiment [Nabielek 1993] are presented and discussed.

Diffusion of Silver in Single Crystalline 6H-SiC

2008 ◽  
Author(s):  
T. T. Hlatshwayo ◽  
N. G. van der Berg ◽  
E. Friedland ◽  
J. B. Malherbe ◽  
P. Chakraborty
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Nuclear Reactor ◽  
Fission Products ◽  
Pyrolytic Carbon ◽  
Reactor Safety ◽  
Fission Fragments ◽  
Coated Particle ◽  
Nuclear Reactor Safety ◽  
Fuel Elements

In a modern high-temperature nuclear reactor, safety is achieved by encapsulating the fuel elements by CVD-layers of pyrolytic carbon and silicon carbide (SiC) to prevent the fission products release. Some studies have raised doubts on the effectiveness of SiC layer as a diffusion barrier to fission fragments due to 110mAg released from the coated particle at high temperatures ranging from 1500°C to 1600°C [1].

Escape of radioactive fission products from leaking fuel elements into an organic coolant

1983 ◽  
Vol 55 (6) ◽  
pp. 797-800 ◽  
Author(s):  
E. I. Shkokov ◽  
V. V. Konyashov ◽  
Yu. G. Simonov ◽  
Yu. V. Chechetkin ◽  
A. D. Yurchenko ◽  
...  
Keyword(s):  
Fission Products ◽  
Organic Coolant ◽  
Fuel Elements

Release of Iodine and Noble Gas Fission Products from Defected Fuel Elements during Reactor Shutdown and Start-Up

1990 ◽  
Vol 92 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Brent J. Lewis ◽  
Roderick D. MacDonald ◽  
Hugues W. Bonin
Keyword(s):  
Noble Gas ◽  
Fission Products ◽  
Start Up ◽  
Reactor Shutdown ◽  
Fuel Elements

Study of Graphite Dust Releasing Behavior in a Depressurization Accident of HTR

2013 ◽  
Author(s):  
Wei Peng ◽  
Ya-nan Zhen ◽  
Xiao-yong Yang ◽  
Su-yuan Yu
Keyword(s):  
Reactor Core ◽  
Fission Products ◽  
Initial Pressure ◽  
Primary Circuit ◽  
Primary Loop ◽  
Fuel Pellets ◽  
Large Size ◽  
Loss Of Coolant Accident ◽  
Loop Surface ◽  
Fuel Elements

The behavior of the graphite dust has an important effect on the safety analysis of High Temperature Gas-cooled Reactors. The graphite dust with the large size will deposit at the bottom of the reactor core by gravity, while the graphite dust with the small size will flow in the primary circuit by carrying of helium. These suspended dusts can deposit in primary loop surface and influence the surface’s feature such as fouling resistance. Moreover, fission products released by fuel elements would enter primary loop and combine with dust, resulting in making the maintenance and repair of steam generator difficult. On the other hand, in the loss-of-coolant accident, when the discharge pipe of fuel pellets was broken, helium will be rejected with the speed of sound. The graphite dust with radioactive contamination will be carried by helium into the environment. The present study experimentally investigates the resuspension of graphite dust in the process of depressurization accident. The effect of both the initial pressure and the velocity of the gas on the resuspension of graphite dust were studied.

Thermal Behaviour of Xenon in a Refractory Metal for Gas Fast Reactor Fuel Elements

2008 ◽  
Vol 272 ◽  
pp. 25-30
Author(s):  
C. Viaud ◽  
G. Carlot ◽  
P. Garcia ◽  
P. Martin ◽  
N. Millard-Pinard ◽  
...  
Keyword(s):  
Fission Products ◽  
Rare Gas ◽  
Burst Release ◽  
Spectrometry Analysis ◽  
Nuclear Fuel Element ◽  
Tungsten Single Crystal ◽  
Analysis Experiment ◽  
Rare Gas Atoms ◽  
Safety Features ◽  
Fuel Elements

Helium cooled Gas Fast Reactors (GFR) are designed for producing energy more efficiently and improving safety features such as a total retention of fission products (Xe, I, Cs). This study deals with the diffusion of xenon in refractory liners dedicated to the retention of fission products produced in GFR fuels. The material (W, Mo, W-Re, Mo-Re) will be located in the heart of the nuclear fuel element, where the operating temperature is in the 1000°C- 1600°C range. For the investigation of thermally activated rare gas behaviour, a γ-spectrometry analysis experiment has been performed on the 133Xenon implanted refractory liner. Preliminary results on the 133Xenon release at 1600°C from a tungsten single crystal is presented. In spite of the low concentration of implanted gas (~ppm) and simple microstructure, the prevailing mechanism appears to be complex. One and two dimensional diffusion models are used to characterize or discriminate the highlighted phenomena: burst release, diffusion and trapping of rare gas atoms.

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