The Waste Treatment Centre for Low- and Intermediate Waste (BSC - RAO) and Final Disposal of Conditioned Waste in Slovakia in Operation Since March 2000

Author(s):  
Miroslav Kövér ◽  
Werner Stich

Abstract On the site of the Slovak Nuclear Power Plant Bohunice a complete Waste Treatment Center for low and intermediate solid and liquid waste constructed. The facilities for volume reduction and further treatment are the incinerator, the high-force compactor and the evaporator. The facility for conditioning the waste is the cementation where the final product — filled concrete containers as the accepted waste package for long-term storage — is produced. The containers are transported to the Slovak Surface Repository for low and intermediate waste. Since March 2000, both projects are in hot operation. The first storage boxes are filled with the containers. First results gained during the first operation phase of the Waste Treatment Center will be discussed.

Author(s):  
Jan Medved ◽  
Ladislav Vargovcik

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.


2007 ◽  
Vol 40 (4) ◽  
pp. 796-798 ◽  
Author(s):  
Bingyun Ao ◽  
Xiaolin Wang ◽  
Yongjun Wei ◽  
Yanzhi Zhang

In order to help resolve unknowns regarding aging effects of uranium during long-term storage of tritium, a number of experiments have been carried out by several researchers. However, almost no literature is available on the structural change of uranium tritide, mainly because its high toxicity and air-sensitivity render appropriate experiments very difficult. In this paper, a simple hermetic sample holder that fits the Philips X'Pert Pro X-ray diffractometer is described. It may be used to study the aging effects of uranium tritide during storage. The sample holder mainly consists of an aluminium container for sample storage and a Mylar window for X-ray measurements. This sample holder can also be used with other air-sensitive, radioactive and toxic materials. In this paper, the first results obtained from X-ray diffraction analysis of uranium hydride are presented.


Author(s):  
Hanchung Tsai ◽  
Yung Y. Liu ◽  
Mark Nutt ◽  
James Shuler

Utilities worldwide are using dry-cask storage systems to handle the ever-increasing number of discharged fuel assemblies from nuclear power plants. In the United States and possibly elsewhere, this trend will continue until an acceptable disposal path is established. The recent Fukushima nuclear power plant accident, specifically the events with the storage pools, may accelerate the drive to relocate more of the used fuel assemblies from pools into dry casks. Many of the newer cask systems incorporate dual-purpose (storage and transport) or multiple-purpose (storage, transport, and disposal) canister technologies. With the prospect looming for very long term storage — possibly over multiple decades — and deferred transport, condition- and performance-based aging management of cask structures and components is now a necessity that requires immediate attention. From the standpoint of consequences, one of the greatest concerns is the rupture of a substantial number of fuel rods that would affect fuel retrievability. Used fuel cladding may become susceptible to rupture due to radial-hydride-induced embrittlement caused by water-side corrosion during the reactor operation and subsequent drying/transfer process, through early stage of storage in a dry cask, especially for high burnup fuels. Radio frequency identification (RFID) is an automated data capture and remote-sensing technology ideally suited for monitoring sensitive assets on a long-term, continuous basis. One such system, called ARG-US, has been developed by Argonne National Laboratory for the U.S. Department of Energy’s Packaging Certification Program for tracking and monitoring drums containing sensitive nuclear and radioactive materials. The ARG-US RFID system is versatile and can be readily adapted for dry-cask monitoring applications. The current built-in sensor suite consists of seal, temperature, humidity, shock, and radiation sensors. With the universal asynchronous receiver/transmitter interface in the tag, other sensors can be easily added as needed. The system can promptly generate alarms when any of the sensor thresholds are violated. For performance and compliance records, the ARGUS RFID tags incorporate nonvolatile memories for storing sensory data and history events. Over the very long term, to affirmatively monitor the condition of the cask interior (particularly the integrity of cover gas and fuel-rod cladding), development of enabling technologies for such monitoring would be required. These new technologies may include radiation-hardened sensors, in-canister energy harvesting, and wireless means of transmitting the sensor data out of the canister/cask.


Author(s):  
Jin Chen ◽  
Xuegang Liu ◽  
Yanchao Zhang ◽  
Qian’ge He ◽  
Jianchen Wang

High-level liquid waste (HLLW) generated from reprocessing process contains actinides, lanthanides, fission products (FP) and a significant amount of nitrate ion. The partitioning and transmutation concept has been introduced for reducing the long-term hazards of HLLW. Several chemical separation processes mainly based on solvent extraction methods have been proposed to treat HLLW. However, solids consisting mainly Mo and Zr are known to form in HLLW during its long-term storage, Solid formations influence the composition of HLLW and the downstream solvent extraction process. To understand the precipitation behavior and stability of HLLW during its long-term storage, simulated HLLW (prepared as raffinate solution from LWR spent fuel reprocessing, 1AW solution) was prepared. Preliminary studies on solid formation behaviors with regard to the precipitation formation during refluxing and aging (representing a long-term storage) were carried out. Precipitation kinetics of major FPs such as Zr, Mo, Ru, rare earth elements, and etc. have been studied; The effect of phosphate ion concentration and temperature on solids formation were also experimentally examined. The formation conditions and the mechanism of solids were discussed.


2020 ◽  
Author(s):  
Sarah Weihmann ◽  
Jobst Maßmann

<p>Nuclear power generation became popular in the 1950s in industrialised countries as an alternative to fossil energy sources to provide large amounts of low cost, low carbon energy. Currently 6% of the world’s energy supply is produced in 451 nuclear reactors across 30 countries. However, nuclear power generation has a serious disadvantage and hidden cost: the accumulation and disposal of spent fuel or high level nuclear waste (HLW) - notably highly radioactive nuclear fission products and the absence of suitable long-term storage solutions, threatening livestock and the environment. Sustainable disposal of HLW holds many challenges: fluid and heat transfer may induce strongly coupled undesirable thermal, hydrological, mechanical and chemical processes.</p><p>A crystalline rock repository construction license has been accomplished by Finland in 2015 for the first long-term HLW repository worldwide. In Germany, a consortium of federal offices is exploring the opportunity of establishing a long-term underground repository in crystalline rock for HLW as an alternative to potential repositories in salt rock and mudrock.</p><p>The aim of this research is to de-risk hypothetical storage solutions for long-term HLW repositories in Germany in crystalline rock. As no geological site must be alluded to for legal reasons during the repository site investigation process at the time being, flow is modelled for a generic fractured rock site based on academic studies of crystalline rock. An inverse problem approach is applied to investigate hydraulic site requirements for the long-term storage of HLW and provide footing for the analysis of coupled thermal, hydrological, mechanical and chemical processes. </p><p>This work demonstrates progress towards finding a long-term storage solution for HLW in Germany through evaluating hydrological processes in a generic crystalline rock site. Through Oda analysis and simulating steady-state flow and particle tracking in a synthetic discrete fracture network (DFN), degrees of fracture connectivity and hydraulic conductivity of fractures have been identified for the hydraulic (boundary) conditions in a repository in crystalline rock.</p>


2001 ◽  
Vol 6 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas ◽  
I. Juodeikienė ◽  
A. Kajalavičius

A model of moisture movement in wood is presented in this paper in a two-dimensional-in-space formulation. The finite-difference technique has been used in order to obtain the solution of the problem. The model was applied to predict the moisture content in sawn boards from pine during long term storage under outdoor climatic conditions. The satisfactory agreement between the numerical solution and experimental data was obtained.


Diabetes ◽  
1997 ◽  
Vol 46 (3) ◽  
pp. 519-523 ◽  
Author(s):  
G. M. Beattie ◽  
J. H. Crowe ◽  
A. D. Lopez ◽  
V. Cirulli ◽  
C. Ricordi ◽  
...  

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