Development of Safety Assessment Code for Decommissioning of Nuclear Facilities  (DecDose)

Shimada, Taro; Ohshima, Soichiro; Sukegawa, Takenori

doi:10.1299/jpes.4.40

Cited by 8 publications

(4 citation statements)

References 1 publication

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“…Possible exposure pathways resulting from the discharges of radionuclides and radiation during dismantling activities under normal conditions and accidents are shown in Fig. 1 (taken from [24]).…”

Section: Analysis Of Risks Due To Events and Incidentsmentioning

confidence: 99%

Preliminary safety analysis at the decommissioning of the WWR-M research reactor

Lobach¹,

Lobach²,

Shevel³

2022

Nucl. Phys. At. Energy

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Following the demands established by the current Ukrainian legislation, the Decommissioning Concept for the WWR-M research reactor was recently approved. The Concept envisages a strategy of immediate dismantling; it identifies and justifies the main technical and organizational measures for the preparation and implementation of decommissioning, the sequence of planned works and activities, as well as the necessary conditions and infrastructure. Decommissioning requires proper planning and demonstration that all planned dismantling works will be carried out safely. Presented safety assessment is a mandatory component of the Concept and the most important element of the overarching technological scheme. The purpose of the safety analysis is to provide input for detailed planning on how to ensure safety during decommissioning. Based on the results of the safety analysis, the measures to ensure radiation protection are defined while justifying their necessity and sufficiency.

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Section: Analysis Of Risks Due To Events and Incidentsmentioning

confidence: 99%

Preliminary safety analysis at the decommissioning of the WWR-M research reactor

Lobach¹,

Lobach²,

Shevel³

2022

Nucl. Phys. At. Energy

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“…In the immediate aftermath of an earthquake or typhoon, broken reinforced concrete structures must be dismantled to rescue people and restore the infrastructure. Cracking the concrete structures of nuclear power plants is one such application [ 2 , 3 ]. The cracking of concrete reinforced by steel at dangerous sites with high radiation concentrations [ 4 ] and contaminated water is dangerous for workers and may cause environmental pollution [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Dismantling of Reinforced Concrete Using Steam Pressure Cracking System: Drilling and Crack Propagation

et al. 2023

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This study investigated a new dismantling system for concrete structures using a steam pressure cracking agent. We improved the mechanical systems such that it can drill through reinforcing steel bars. Therefore, the control method of the system and shape of the drill tip were improved. When the drill tip is stuck with chips and stopped, it is automatically pulled out and reinserted to recover the rotation. By changing the tip angle of the drill bit from 75° to 90°, it became possible to cut reinforcing bars, which were difficult to cut previously. In addition, we designed a crawler-type mechanical system and improved it such that it can be moved to the appropriate position and operated at any angle. This study revealed that the energy required for the drilling process accounts for more than 90% of the total dismantling energy. Through experiments using an impact hammer drill and observations of fracture surfaces using a three-dimensional scanner, we analysed the characteristics of reinforced concrete. In addition, the feasibility of the design for dismantling reinforced concrete was confirmed based on the determined energy associated with crack propagation.

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“…Demolition of large reinforced concrete structures at actual hazard sites is dangerous for workers and may cause environmental pollution. The dismantling of nuclear power plant buildings is a typical example [1,2]. The purpose of this study was to develop a total remote demolition system that is safe and does not cause environmental problems.…”

Section: Introductionmentioning

confidence: 99%

Demolition of Reinforced Concrete by Steam Pressure Cracking System

Kamiya¹,

Takahashi²,

Miyano³

et al. 2022

J. Mater. Appl.

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The authors developed an environment-friendly demolition mechanical system for a large reinforced concrete structure for an actual site. The steam pressure cracking agent (SPC, non-explosive) is a method that can safely and quickly separate concrete because it produces lesser vibration and sound than the blasting method, which uses explosives. The authors showed that the direction of cracking can be controlled by an induction hole. The principle of control is that the elastic wave of the compression stress generated from the SPC reaction changes to a tensile elastic wave at the induction hole, which initiates a crack. Furthermore, in the SPC method, a large amount of concrete powder generated by the explosion method was not produced, and there was no risk of secondary contamination by fine concrete powder. The area over which the crack propagated depends on the energy generated from the SPC. The relationship between the two is linear. For reinforced concrete, the energy of the SPC is used for both the destructive energy of the concrete and the energy of the cutting of the reinforcing steel bar, which quickly breaks with low energy. By applying an SPC to dismantle large reinforced concrete structures, controlled cracking can be achieved safely and quickly without any environmental pollution. A fracturing method using a SPC is an effective method for the decommissioning of nuclear power plants and the dismantling of concrete structures. In this report, we report a remote drilling system that can be used to remotely install loading holes and guiding holes for the SPC and perform effective controlled fracturing.

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Development of Safety Assessment Code for Decommissioning of Nuclear Facilities (DecDose)

Cited by 8 publications

References 1 publication

Preliminary safety analysis at the decommissioning of the WWR-M research reactor

Preliminary safety analysis at the decommissioning of the WWR-M research reactor

Dismantling of Reinforced Concrete Using Steam Pressure Cracking System: Drilling and Crack Propagation

Demolition of Reinforced Concrete by Steam Pressure Cracking System

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