Basic Experimental Study on Effectiveness of Nuclear Waste Long-Term Storage Containers With PAR for Reducing Concentration of Hydrogen Gas: Part 2 — Hydrogen Behavior in a Small-Scale Modeled Container

2018 ◽  
Author(s):  
Y. Hiraki ◽  
G. Takase ◽  
Y. Suzuki ◽  
Y. Tanaka ◽  
K. Takase
Keyword(s):  
Hydrogen Concentration ◽  
Nuclear Power ◽  
Hydrogen Gas ◽  
Small Scale ◽  
Storage Container ◽  
Long Term Storage ◽  
Waste Storage ◽  
Experimental Apparatus ◽  
Hydrogen Supply

As for the decommissioning of Fukushima Dai-ichi nuclear power plant (1F), a long-term waste storage container with high safety is requested to store radioactive materials such as fuel debris for a long period of time. Since hydrogen is generated by radioactive decomposition of water, it is important to keep the concentration of hydrogen gas below the explosion limit in order to ensure the safety of the container. Then, use of passive autocatalytic recombiner (PAR) was proposed to reduce the hydrogen concentration. PAR is installed in the container. In order to experimentally confirm the reduction of hydrogen concentration by PAR and hydrogen behavior in the container, an experimental apparatus consisting of a small-scale modeled container and a hydrogen supply system was provided. Preliminary experiments were begun for confirming fundamental performance of the experimental apparatus under the conditions that PAR and simulated fuel debris are not installed in the container. Moreover, the hydrogen behavior in the container was analyzed numerically. In addition, the steam behavior generated by the chemical reaction of hydrogen and oxygen by PAR was also predicted. This paper describes both results of the preliminary experiments and numerical simulations. The experimental results showed that the hydrogen behavior can be predicted using the temperature distributions in the container. The analysis results clarified the controlling factors on the hydrogen behavior and the steam distribution in the container by PAR.

Basic Experimental Study on Effectiveness of Nuclear Waste Long-Term Storage Containers With PAR for Reducing Concentration of Hydrogen Gas: Part 1 — Research Plan and Preliminary Simulation Results

2017 ◽  
Author(s):  
Y. Tanaka ◽  
Y. Suzuki ◽  
K. Takase
Keyword(s):  
Natural Convection ◽  
Radioactive Waste ◽  
Hydrogen Gas ◽  
Small Scale ◽  
Storage Container ◽  
Waste Storage ◽  
Experimental Apparatus ◽  
Flammable Gas ◽  
Research Plan

In the decommissioning of nuclear power plants, the long-term management of radioactive waste of fuel debris, etc. are necessary. In the process, hydrogen which is the flammable gas is generated by the decomposition of water by radiation. Therefore, it is important to ensure the safety of the waste storage container to reduce the concentration of hydrogen gas, and to keep below the explosion limit (4%). Consequently, a basic experiment to investigate the effectiveness of the waste storage container with the flammable gas concentration reduction mechanism using the passive autocatalytic recombiner (PAR) has been planned. The present study describes the research plan to use a small modeled experimental apparatus. In addition, in order to clarify quantitatively natural convection behavior of hydrogen gas due to the decay heat of radioactive materials in the long-term waste storage container, preliminary analyses were performed on the system of a small-scale experimental apparatus in which specification of the long-term radioactive waste storage container is simply simulated. From the present results, the perspective which can predict natural convection phenomena in the long-term waste storage container numerically was obtained.

Fundamental Experiments on Reduction of Hydrogen Concentration in a Long-Term Waste Storage Container with PAR

2018 ◽  
Vol 2018.23 (0) ◽  
pp. C112
Author(s):  
Kazuyuki TAKASE ◽  
Yoshihisa HIRAKI ◽  
Gaku TAKASE ◽  
Yota SUZUKI ◽  
Yusei TANAKA
Keyword(s):  
Hydrogen Concentration ◽  
Storage Container ◽  
Waste Storage

Assessment of Package Performance During Long-Term Storage of Intermediate-Level Radioactive Waste

2003 ◽  
Author(s):  
A. V. Chambers ◽  
W. R. Rodwell ◽  
M. Kelly ◽  
A. R. Hoch ◽  
A. J. Baker
Keyword(s):  
Extended Period ◽  
Intermediate Level ◽  
Passive Safety ◽  
Long Term Storage ◽  
Waste Storage ◽  
Disposal Option ◽  
Intermediate Level Radioactive Waste ◽  
The Uk ◽  
The Impact

In the UK, the need for the long-term management of intermediate-level radioactive wastes arises from the absence of an established deep disposal option. As a consequence there is a requirement to demonstrate the ‘passive safety’ of waste packages in stores over a necessarily lengthy period (perhaps 150 years or more). ‘Passive safety’ is taken here to imply that the waste packages themselves would remain safe without intervention; it is assumed however, that the store building and associated infrastructure would need to be actively maintained and that the store may need to be ventilated. Importantly, methods for waste storage also need to ensure that possible future options for disposal are not foreclosed. An extended period of storage suggests that emphasis will need to be placed by waste producers on understanding a number of issues such as: • the impact of corrosion on container integrity; • the assessment of container vents and other features as a pathway for the release of radioactivity; • the extent to which wastes are conditioned for storage and the selection of appropriate methods; • the generation and behaviour of toxic or flammable gases in the storage facility; and the mitigating steps that might be needed to address adverse impacts (e.g. the type of ventilation that the store requires). In this paper, we review the requirements and current state of knowledge relevant to the assessment of operational releases of radioactive, flammable and toxic gases from wastes in long-term interim storage.

scholarly journals An automated system to mount cryo-cooled protein crystals on a synchrotron beamline, using compact sample cassettes and a small-scale robot

2002 ◽  
Vol 35 (6) ◽  
pp. 720-726 ◽  
Author(s):  
Aina E. Cohen ◽  
Paul J. Ellis ◽  
Mitchell D. Miller ◽  
Ashley M. Deacon ◽  
R. Paul Phizackerley
Keyword(s):  
Synchrotron Radiation ◽  
Industrial Robot ◽  
Automated System ◽  
Small Scale ◽  
Compact Sample ◽  
Long Term Storage ◽  
Radiation Laboratory ◽  
And Storage ◽  
Term Storage

An automated system for mounting and dismounting pre-frozen crystals has been implemented at the Stanford Synchrotron Radiation Laboratory (SSRL). It is based on a small industrial robot and compact cylindrical cassettes, each holding up to 96 crystals mounted on Hampton Research sample pins. For easy shipping and storage, the cassette fits inside several popular dry-shippers and long-term storage Dewars. A dispensing Dewar holds up to three cassettes in liquid nitrogen adjacent to the beamline goniometer. The robot uses a permanent magnet tool to extract samples from, and insert samples into a cassette, and a cryo-tong tool to transfer them to and from the beamline goniometer. The system is simple, with few moving parts, reliable in operation and convenient to use.

scholarly journals Pressure Indication of 3013 Inner Containers Using Digital Radiography

2004 ◽  
Author(s):  
S. J. Hensel
Keyword(s):  
Digital Radiography ◽  
Lower Surface ◽  
Department Of Energy ◽  
Storage Container ◽  
Digital Radiography System ◽  
Long Term Storage ◽  
Radiography System ◽  
Bearing Materials ◽  
Non Destructive

Plutonium bearing materials packaged for long term storage per the Department of Energy Standard 3013 (DOE-STD-3013) are required to be examined periodically in a non-destructive manner (i.e. without compromising the storage containers) for pressure buildup. Radiography is the preferred technology for performing the examinations. The concept is to measure and record the container lid position. As a can pressurizes the lid will deflect outward and thus provide an indication of the internal pressure. A radiograph generated within 30 days of creation of each storage container serves as the baseline from which future surveillance examinations will be compared. A problem with measuring the lid position was discovered during testing of a digital radiography system. The solution was to provide a distinct feature upon the lower surface of the container lid from which the digital radiography system could easily track the lid position.

Decommissioning of the A-1 NPP Long-Term Storage Facility

2009 ◽  
Author(s):  
Jan Medved ◽  
Ladislav Vargovcik
Keyword(s):  
Nuclear Power ◽  
Water Jet ◽  
Stage I ◽  
Stage Ii ◽  
Storage Facility ◽  
Spent Fuel ◽  
Special Equipment ◽  
Long Term Storage ◽  
Term Storage

The paper deals with experience, techniques and new applied equipment durig undergoing decommissioning process of the A-1 NPP long-term pool storage and the follow-up decommissioning plan. For rad-waste disposal of the long-term pool storage (where most of the contaminants had remained following the removal of spent fuel) special equipment has been developed, designed, constructed and installed. The purpose of this equipment is the restorage, drainage and fragmentation of cartridges (used as a spent fuel case), as well as treatment of sludge (located at the pool bottom) and of the remaining liquid radwaste. The drainage equipment for cartridges is designed for discharging KCr2 solution from cartridges with spent fuel rods into the handling storage tank in the short-term storage facility and adjustment of the cartridges for railway transport, prior to the liquidation of the spent fuel rod. The equipment ensures full remote visual control of the process and exact monitoring of its technical parameters, including that of the internal nitrogen atmosphere concentration value. Cartridges without fuel and liquid filling are transferred to the equipment for their processing which includes fragmentation into smaller parts, decontamination, filling into drums with their sealed closing and measurement of radioactive dose. For the fragmentation, special shearing equipment is used which leaves the pipe fragment open for the following decontamination. For cleaning the cartridge bottom from radioactive sludge water jet system is used combined with slow speed milling used for preparing the opening for water jet nozzle. The sludge from the cartridge bottom is fixed into ceramic matrix. Nuclear Power Plant JE A-1 (since 1980 in decommissioning) is situated in the locality of Jaslovske´ Bohunice. So far the decommissioning of the Long-term storage was carried out within Stage I of A-1NPP decommissioning. This year the Stage I of decommissioning finished, and the performance of Stage II of decommissioning was started. Decommissioning of the long-term storage facility continues within Stage II of the A-1 NPP decommissioning process.

Reprocessing Nuclear Fuel Containing Polymers

2008 ◽  
Author(s):  
Fiquet Olivier ◽  
Boivinet Raynal ◽  
Trabuc Pierre
Keyword(s):  
Thermal Treatment ◽  
Nuclear Fuel ◽  
Thermal Cycle ◽  
Hydrogen Gas ◽  
Second Phase ◽  
Gas Treatment ◽  
R And D ◽  
Long Term Storage ◽  
Term Storage

Organic radiolysis generates enough hydrogen gas to question the safety of radioactive fuel transportation and long-term storage. A safety analysis points out the absolute necessity to get rid of all organic substances in nuclear fuel long-term storage. In the past decades, R and D activities have been producing quantities of rod fuel samples embedded in polymer resins for characterization purposes. Until recently, resin has not been removed from samples and today large sample quantities have to be reprocessed. The “STAR” nuclear facility at CEA Cadarache in France devoted to used fuel stabilization and conditioning, recently decided to implement in the hot cell a particular process to achieve the safety requirements. In order to define a versatile process, efficient for any kind of polymer, thermal treatment has been chosen over a chemical or mechanical process. The definition of this particular thermal treatment must take into account; the hot cell environment, the nuclear safety rules and the behavior of resins. A prototypic furnace has been built for study purposes and thermal cycle validation. Today, the thermal cycle has been defined in two phases as follow: First phase: pyrolysis is used to transform resin into residues and gases. A post gas treatment will be added to the furnace for total gas oxidation. Second phase: Air thermal treatment will achieve the complete residue oxidation and guarantee a hydrogen free product. The final equipment will be available in 2009 for testing and validation cycles with a radioactive free simulator before it is to be implemented in the hot cell in 2010.

Process of Drying Post-Harvest Hops (Humulus lupulus) for Small-Scale Producers Using a Novel Drying Rig

EDIS ◽  
2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Sean M. Campbell ◽  
Brian J. Pearson
Keyword(s):  
Plant Material ◽  
Humulus Lupulus ◽  
The State ◽  
Small Scale ◽  
Post Harvest ◽  
Long Term Storage ◽  
Term Storage

Fresh horticultural goods often require drying post-harvest to preserve quality and allow for successful long-term storage of plant material. Given the influx of hops cultivation in the state of Florida, this 5-page publication will help Florida hops growers and hobby brewers to understand how to efficiently dry hops prior to storage. Written by Sean Campbell and Brian Pearson and published by the UF/IFAS Environmental Horticulture Department, January 2019. http://edis.ifas.ufl.edu/ep568

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