Determination of scale deposition in a flare line by neutron back-diffusion

2021 ◽  
Vol 168 ◽  
pp. 109424
Author(s):  
Salah Al-Smairat ◽  
Mohammed M. Damoom ◽  
Mohammed S. Al-Johani ◽  
Samir Abdul-Majid
Keyword(s):  
Back Diffusion ◽  
Scale Deposition

Determination of the Porosity, Permeability and Diffusivity of Rock in the Excavation-Disturbed Zone Around Full-Scale Deposition Holes Using the He-Gas Method

1999 ◽  
Vol 556 ◽  
Author(s):  
J. Autio ◽  
J. Timonen ◽  
T. Aaltonen ◽  
M. Laajalahti ◽  
K. Kuoppamäki ◽  
...  
Keyword(s):  
Nuclear Waste ◽  
Granitic Rock ◽  
Nuclear Waste Repository ◽  
Direction Parallel ◽  
Disturbed Zone ◽  
Excavation Disturbed Zone ◽  
Waste Repository ◽  
Effective Diffusivities ◽  
Scale Deposition

AbstractIn a nuclear waste repository, rock in the excavation-disturbed zone adjacent to the walls of deposition holes for waste canisters is a potential pathway for the transport of corrosive agents and radionuclides. Three experimental holes the size of deposition holes in a KBS-3 type repository (depth 7.5 m and diameter 1.5 m) were bored in hard granitic rock in the Research Tunnel at Olkiluoto and the porosities, effective diffusivities and permeabilities of rock in the excavation-disturbed zone were determined in a direction parallel to the disturbed surface using He-gas methods. Permeability and diffusivity in a direction parallel to the rock schistosity was found to be clearly larger than in a direction perpendicular to it.

Determination of radon emanation and back diffusion characteristics of building materials in small chamber tests

1997 ◽  
Vol 32 (4) ◽  
pp. 355-362 ◽  
Author(s):  
Christopher Y.H. Chao ◽  
Thomas C.W. Tung ◽  
Daniel W.T. Chan ◽  
John Burnett
Keyword(s):  
Building Materials ◽  
Radon Emanation ◽  
Back Diffusion ◽  
Small Chamber ◽  
Diffusion Characteristics

Determination of the Structure and Porosity of Rock in the Disturbed Zone Around Experimental Full-Scale Deposition Holes Using the 14C-PMMA Method

1997 ◽  
Vol 506 ◽  
Author(s):  
J. Autio ◽  
M. Slltari-Kauppi
Keyword(s):  
Granitic Rock ◽  
Gradual Transition ◽  
Nuclear Waste Repository ◽  
Gas Release ◽  
The Novel ◽  
Transport Pathway ◽  
Bentonite Buffer ◽  
Disturbed Zone ◽  
Scale Deposition

ABSTRACTIn a nuclear waste repository the disturbed rock zone adjacent to the deposition holes of waste canisters is a potential transport pathway of radionuclides. The properties of the disturbed zone may also play an important role in the saturation of the bentonite buffer and in gas release.Three experimental holes of the size of deposition holes (depth 7.5 m and diameter 1.5 m) in a KBS-3 type repository were bored in hard granitic rock in the Research Tunnel at Olkiluoto. The disturbed rock zone caused by the boring was analyzed including determination of the porosity and structure of the disturbed and intact rock. These were studied in the laboratory using core samples by using the novel 14C-polymethylmethacrylate (14C-PMMA) method. In addition the structure of the disturbed zone was also examined using scanning electron and optical microscopy. A distinct zone of disturbance adjacent to the surface of the deposition holes was found. This disturbed zone was further divided into three separate sub-zones with gradual transition between the zones. It was also observed that the machine and tool factors have effect on the properties of the disturbed zone.

DETERMINATION OF THE MEAN FREE PATH OF SLOW ELECTRONS BY THE MEASUREMENT OF BACK-DIFFUSION IN HELIUM AND ARGON

1965 ◽  
Vol 43 (3) ◽  
pp. 422-431 ◽  
Author(s):  
O. J. Orient
Keyword(s):  
Energy Distribution ◽  
Free Path ◽  
Electron Energy ◽  
Field Intensity ◽  
Mean Free Path ◽  
Back Diffusion ◽  
Test Device ◽  
The Mean ◽  
Slow Electrons

In the theoretical examination of back-diffusion Varney found a relationship between the extent of the back-diffusion of electrons starting from the cathode and the distance to the cathode. When adequate conditions are ensured the dependence of back-diffusion on distance permits the determination of the mean free path of the electrons. A test device has been developed to measure back-diffusion as a function of the distance to the cathode, for electrons that have an energy distribution corresponding to the specified pressure and the field intensity. From the dependence on distance, mean free paths for helium and argon gases in the range from X/p = 0.5 volt/cm. mm Hg to X/p = 5 volts/cm. mm Hg have been determined. The results are in fair accordance with the mean free paths computed by Barbiere from electron-energy distribution values. Variances have been found, however, with Townsend's and Bailey's data, particularly in the case of argon, where the free path of electrons depends greatly on velocity.

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