Compacted bentonite as a source of substrates for sulfate-reducing microorganisms in a simulated excavation-damaged zone of a spent nuclear fuel repository

ABSTRACTThe role of excavation damaged zone (EDZ) in a KBS-3 type repository for spent nuclear fuel depends significantly on the design of the engineered barrier systems such as tunnel backfill since one obvious function of the backfill is to prevent the growth of EDZ. Main results of EDZ studies based on using 14C-PMMA method carried out at Äspö Hard Rock Laboratory in Sweden, and at Research Tunnel at Olkiluoto in Finland by Posiva and SKB in co-operation are presented. The significance of the results is evaluated quantitatively and qualitatively. The EDZ around the deposition hole on migration of radionuclides diffusing out of a waste canister was found unlikely to be a significant migration route in the absence of large hydraulic gradients. According to the study the EDZ caused by state-of-the-art drill and blast excavation adjacent to walls and roof of deposition tunnels was found negligible, however the EDZ adjacent to deposition tunnel floor is evidently more extensive and more significant.

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The Effect of the Excavation Damaged Zone Adjacent to the Walls of Deposition Holes on the Migration of Radionuclides

MRS Proceedings ◽

10.1557/proc-663-645 ◽

2000 ◽

Vol 663 ◽

Cited By ~ 1

Author(s):

J. Autio ◽

A. Hautojärvi ◽

J-P. Salo

Keyword(s):

Hydraulic Conductivity ◽

Nuclear Waste ◽

Nuclear Waste Repository ◽

Migration Route ◽

Compacted Bentonite ◽

Excavation Damaged Zone ◽

Damaged Zone ◽

Hydraulic Gradients ◽

Waste Repository ◽

And Diffusion

ABSTRACTThe excavation damaged rock zone (EDZ) adjacent to the surface of deposition holes in a nuclear waste repository has been considered to be a potential pathway for the flow of water and the migration of radionuclides diffusing out of a waste canister via the bentonite barrier. The properties of the excavation-damaged rock zone adjacent to the surface of experimental deposition holes in the Research Tunnel at Olkiluoto on the southwest coast of Finland have been measured and are used in this study to evaluate the effect of the excavation damaged rock zone on the transport of radionuclides escaping from a waste canister. Since the hydraulic conductivity of compacted bentonite is low, the predominant mode of migration of nuclides through such material will be diffusion. The effect of the excavation-damaged rock zone on the transport of radionuclides was analyzed by comparing two different cases: 1) diffusion through the bentonite and 2) transport through the excavation damaged rock zone by the processes of advection and diffusion. According to this study, hydraulic gradients three orders of magnitude higher than those estimated to currently exist would be required to achieve the transfer of significant quantities of non-sorbing neutral nuclides through the excavation-damaged rock zone. According to this evaluation, the excavation damaged rock zone is unlikely to be a significant migration route in normal cases in the absence of large hydraulic gradients.

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Convective processes in spent nuclear fuel canisters

10.1615/ihtc12.4380 ◽

2002 ◽

Author(s):

Glenn E. McCreery ◽

Keith G. Condie ◽

Randy C. Clarksean ◽

Donald M. McEligot

Keyword(s):

Nuclear Fuel ◽

Spent Nuclear Fuel ◽

Convective Processes ◽

Nuclear Fuel Canisters

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A new approach to spent nuclear fuel recycling for light water reactors in the frame of remix concept

Izvestiya Wysshikh Uchebnykh Zawedeniy Yadernaya Energetika ◽

10.26583/npe.2020.1.07 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 67-77

Author(s):

Nikita Vladimirivich Kovalyov ◽

Boris Yakovlevich Zilberman ◽

Nikolay Dmitrievich Goletskiy ◽

Andrey Borisovich Sinyukhin

Keyword(s):

Nuclear Fuel ◽

Spent Nuclear Fuel ◽

Light Water Reactors ◽

New Approach ◽

Light Water ◽

Water Reactors

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Small nuclear power plants for power supply to the arctic regions: spent nuclear fuel radioactivity assessment

Izvestiya Wysshikh Uchebnykh Zawedeniy Yadernaya Energetika ◽

10.26583/npe.2018.1.08 ◽

2018 ◽

Vol 2018 (1) ◽

pp. 75-86

Author(s):

Vadim Alekseevich Naumov ◽

Sergey Andreevich Gusak ◽

Andrey Vadimovich Naumov

Keyword(s):

Nuclear Fuel ◽

Power Supply ◽

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Spent Nuclear Fuel ◽

The Arctic ◽

Arctic Regions

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Safety of Extended Dry Storage of Spent Nuclear Fuel SEDS2020: International online-workshop

Kerntechnik ◽

10.3139/124.020061 ◽

2020 ◽

Vol 85 (6) ◽

pp. 412-412

Author(s):

M. Stuke

Keyword(s):

Nuclear Fuel ◽

Spent Nuclear Fuel ◽

Dry Storage

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Development of Criticality Accident Alarm System to Ensure Safe Retrieval of Spent Nuclear Fuel from Lepse Floating Maintenance Base

ANRI ◽

10.37414/2075-1338-2020-100-1-45-53 ◽

2020 ◽

pp. 45-53

Author(s):

A. Lachugin ◽

M. Kocherygin ◽

A. Gayazov ◽

Yury Martynyuk ◽

A. Vasil'ev

Keyword(s):

System Design ◽

Nuclear Fuel ◽

Spent Nuclear Fuel ◽

Alarm System ◽

Criticality Accident ◽

Hazardous Area ◽

Key Features

The paper presents basic results of development of a criticality accident alarm system to ensure safe retrieval of the spent nuclear fuel from the Lepse Floating Maintenance Base. The key features and engineering aspects of the system design are described. Locations of criticality detector units and selected alarm level settings are justified, hazardous area boundaries were identified, and parameters to identify inadequately protected zones were calculated. The SRKS-01D criticality accident alarm system by SPC “Doza” was selected as base equipment. The system was commissioned in 2019 and has been successfully operated for more than 6 months.

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