scholarly journals Near-field/Far-field Interface of a Near-Surface Low-Level Radioactive Waste Site

2003 ◽  
Vol 807 ◽  
Author(s):  
I. R. Beadle ◽  
J. Graham ◽  
S. Boult ◽  
V. L. Hand ◽  
P. Warwick ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Iron Hydroxide ◽  
Near Field ◽  
Experimental Studies ◽  
Far Field ◽  
Near Surface ◽  
Interface Zone ◽  
Low Level ◽  
Modelling Studies ◽  
Low Level Radioactive Waste

ABSTRACTExperimental and Modelling studies have been used to investigate the biogeochemical processes occurring at the interface zone between the near-field and far-field of the Drigg Low-Level radioactive Waste (LLW) trenches. These have led to a conceptual model of interface biogeochemistry, which has subsequently been modelled by the BNFL code known as the Generalised Repository Model (GRM). GRM simulations suggest that as organic rich leachate migrates into the far-field, iron III minerals such as iron hydroxide will dissolve, and reduced iron minerals such as siderite will precipitate due to microbial processes. Batch and column experimental studies have verified this conceptual understanding. Some unexpected processes, such as the presence of nitrate enhancing sulphate reduction, were also observed

The biogeochemical behaviour of U(VI) in the simulated near-field of a low-level radioactive waste repository

2006 ◽  
Vol 21 (9) ◽  
pp. 1539-1550 ◽  
Author(s):  
James R. Fox ◽  
Robert J.G. Mortimer ◽  
Gavin Lear ◽  
Jonathan R. Lloyd ◽  
Ian Beadle ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Near Field ◽  
Radioactive Waste Repository ◽  
Low Level ◽  
Waste Repository ◽  
Low Level Radioactive Waste

BNFL Lysimeter Proaramme to Investigate the Leachina of Radlonuclides from Low-Level Radioactive Waste

1992 ◽  
Vol 294 ◽  
Author(s):  
K. Clayton ◽  
R. Clegg ◽  
R.G.G. Holmes ◽  
G.W.A. Newton
Keyword(s):  
Radioactive Waste ◽  
Near Field ◽  
Analytical Data ◽  
Nuclear Fuels ◽  
Gas Generation ◽  
Effective Technique ◽  
Low Level ◽  
Leaching Behaviour ◽  
Radionuclide Release ◽  
Low Level Radioactive Waste

ABSTRACTBritish Nuclear Fuels ple has initiated an experimental programme to measure the leaching behaviour of radionuclides from various low level radioactive waste (LLW) mareials using Lysimeters. The programme commenced in 1986 and to date 10 lysimeters have been commissioned. These have concentrated on simulating shallow trench conditions but a further programme is now planned to study concrete vault environments. The aim of the study is to provide information on leaching processes as part of the ongoing Drigg Near Field Programme, and also to yield input data for radiological assessment purposes. Towards this end, data have been gained from the lysimeters on basic chemistry, gas generation and radionuclide Release Coefficients. This paper concentrates on one of the lysimeters which has recently been decommissioned and for which interim analytical data are available. Some general comments are given on BNFL's experience using lysimeters and their applicability as a rapid and effective technique for studying near field degradation processes.

DEVELOPMENT OF VERY LOW-LEVEL RADIOACTIVE WASTE SEQUESTRATION PROCESS CRITERIA

2015 ◽  
Vol 4 (2) ◽  
pp. 119-123
Author(s):  
Nicholas Chan ◽  
Pierre Wong
Keyword(s):  
Radioactive Waste ◽  
Waste Management ◽  
Low Cost ◽  
Regulatory Control ◽  
Environmental Footprint ◽  
Near Surface ◽  
Low Level ◽  
High Degree ◽  
Low Level Radioactive Waste

Segregating radioactive waste at the source and reclassifying radioactive waste to lower waste classes are the key activities to reduce the environmental footprint and long-term liability. In the Canadian Standards Association’s radioactive waste classification system, there are 2 sub-classes within low-level radioactive waste: very short-lived radioactive waste and very low-level radioactive waste (VLLW). VLLW has a low hazard potential but is above the Canadian unconditional clearance criteria as set out in Schedule 2 of Nuclear Substances and Devices Regulations. Long-term waste management facilities for VLLW do not require a high degree of containment and isolation. In general, a relatively low-cost near-surface facility with limited regulatory control is suitable for VLLW. At Canadian Nuclear Laboratories’ Chalk River Laboratories site an initiative, VLLW Sequestration, was implemented in 2013 to set aside potential VLLW for temporary storage and to be later dispositioned in the planned VLLW facility. As of May 2015, a total of 236 m3 resulting in approximately $1.1 million in total savings have been sequestered. One of the main hurdles in implementing VLLW Sequestration is the development of process criteria. Waste Acceptance Criteria (WAC) are used as a guide or as requirements for determining whether waste is accepted by the waste management facility. Establishment of the process criteria ensures that segregated waste materials have a high likelihood to meet the VLLW WAC and be accepted into the planned VLLW facility. This paper outlines the challenges and various factors which were considered in the development of interim process criteria.

scholarly journals A study on waterproof capabilities of the bentonite-containing engineered barrier used in near surface disposal for radioactive waste

2021 ◽  
Vol 7 (1) ◽  
pp. 37-42
Author(s):  
Cao Nguyen Luu ◽  
Ba Tien Nguyen ◽  
Thu Hien Doan Thi ◽  
Van Chinh Nguyen ◽  
Huu Anh Vuong
Keyword(s):  
Radioactive Waste ◽  
Fuel Cycle ◽  
Radioactive Waste Disposal ◽  
Radioactive Material ◽  
Disposal Site ◽  
Plastic Tube ◽  
Near Surface ◽  
Low Level ◽  
Uranium Tailings ◽  
Low Level Radioactive Waste

Study of nuclear fuel cycle in Vietnam at the aspect of domestic production, the exploitation and process of uranium ore were began. These processes generated large amounts of radioactive waste overtiming. The naturally occurring radioactive material and technologically enhanced radioactive material (NORM/TENORM) waste, which would be large, needs to be managed and disposed reasonably by effectivemethods. It was therefore very important to study the model of the radioactive waste repository, where bentonite waterproofing layer would be applied for the low and very low level radioactive waste in disposal site. The aim of this study was to obtain the preliminary parameters for low-level radioactive waste disposal site suitable with the conditions of Vietnam. The investigation of the ratio between soil and bentonite was interested in the safety of the uranium tailings disposal site. The experiments with some layers of waterproofing material with the ratio of soil and bentonite are 75/25; 50/50; 25/75 were carried out to test the moving of uran nuclide through these waterproofing material layers. Waterproofing layers containing bentonite combined with soil were compacted into PVC pipes. One end of the plastic tube is sealed, the other end is embedded in a solution containing uranium nuclide. Analyzing the uranium content in each layers (0,1 cm) of material pipe is to determine the uranium nuclide adsorption from solution into the material in the different ratios at the different times: 1, 2 and 3 month. The results showed that the calculated average speeds of the migration of uranium nuclide into the soil- bentonite layer are 5.4.10-10, 5.4.10-10 and 3,85.10-10 m/s and thickness waterproofing layer (for 300 years) are 4,86 m, 4,86 m and 3,63 m for layer with the ratio of soil and bentonite are 75/25; 50/50; 25/75 respectively

Discussion on Very Low-Level Radioactive Waste near Surface Disposal

2013 ◽  
Vol 807-809 ◽  
pp. 1207-1210 ◽  
Author(s):  
Hai Ying Chen ◽  
Chun Ming Zhang ◽  
Shao Wei Wang ◽  
Qiao Feng Liu ◽  
Jing Ru Han
Keyword(s):  
Radioactive Waste ◽  
Waste Disposal ◽  
Early Period ◽  
Radioactive Waste Disposal ◽  
Nuclear Facilities ◽  
Near Surface ◽  
Barrier Materials ◽  
Low Level ◽  
Low Level Radioactive Waste ◽  
Natural Barriers

Radioactive waste disposal is one of the most sensitive environmental problems. As the arriving of decommissioning of early period nuclear facilities in China, large amounts of very low-level radioactive waste will be produced inevitably. The domestic and abroad definitions about very low-level radioactive waste and its disposal were introduced, and then siting principles of near surface disposal of very low-level radioactive waste were discussed. The near surface disposal sites’ natural barriers were analyzed from the crustal structure and the radionuclide adsorption characteristics of natural barriers. The near surface disposal sites’ engineering barriers were analyzed from the repository design and the repository barrier materials selection. Finally, the improving direction of very low-level radioactive waste disposal was proposed, which would promote the study of very low-level radioactive waste disposal in China.

Experiments and Modelling Studies Concerning Localised Corrosion of Carbon Steel and Stainless Steel Containers for Intermediate- and Low-Level Radioactive Waste

1992 ◽  
Vol 294 ◽  
Author(s):  
A.R. Hoch ◽  
C.C. Naish ◽  
S.M. Sharland ◽  
A.C. Smith ◽  
K.J. Taylor
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Radioactive Waste ◽  
Pitting Corrosion ◽  
Environmental Conditions ◽  
Crevice Corrosion ◽  
Experimental Studies ◽  
Modelling Studies ◽  
The Uk ◽  
Low Level Radioactive Waste

ABSTRACTCurrent plans for disposal of low- and intermediate-level radioactive wastes (LLW and ILW) in the UK include enclosing much of the waste in carbon steel or stainless steel containers. Modelling and experimental studies that aim to characterise the period and extent of the localised corrosion in these containers are described. The period, during which localised corrosion can be initiated and sustained in the post-closure phase of the repository is estimated. The likely modes of localised corrosion are identified, based on further consideration of the environmental conditions to which the metals are exposed. Detailed research in progress includes investigation of the rate of pitting corrosion for carbon steel, and the possible occurrence of crevice corrosion of stainless steel.

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