Emplacement operations

A further documentation has to be compiled after the emplacement operations have finished and the repository closed. The documentation which is needed for a near surface repository is presented in the next paper [10]. 

The behaviour of the sections of the disposal facility already backfilled should be observed during the continuing operational phase until closure of the repository. The aim of these observations is to confirm the predictions and to draw conclusions on long-term safety. These conclusions shall support the final demonstration of long-term safety which in required for the decision to close the repository (see next paper [10]). In order to strengthen the conclusions, the observations may be prolonged for a limited period of time after the end of emplacement operations. The needs or merits of a surveillance period after closure of the disposal facility will also be addressed in the next paper and in paper 21 [11]. 

In a 1997 estimate provided by the vendor, the cost of permeable barrier installed during one year that operates for approximately 20 years would be about 682,000. This estimate was prepared for the Denver Creek site, in the Coeur d Alene district of Idaho. The apatite was assumed to cover a depth of about 5 yd, and the emplacement trench was assumed to be approximately 30 yd across and 8 yd thick. The flow rate through the site was estimated to be 2 ft /sec. For this estimate, design costs were determined to be 48,000 feasibility study costs 110,000 health and safety costs were estimated to be 112,000 the cost of the apatite was placed at 210,000 and monitoring well emplacement and operation, including samples... 

The proposed Swiss repository for SF, HLW, and ILW is situated in the Opalinus Clay of the Zurcher Weinland in northern Switzerland, where an exploratory borehole was drilled near the village of Benken (Nagra 2002a). The Opalinus Clay formation consists of a well-consolidated clay shale, which is suitable for the construction of small, unlined tunnels and larger, lined tunnels at depths of several hundred metres. The engineered barrier system includes the waste containers and the backfill of construction, operation, and emplacement... 

For different operational purposes the weapon system can be made available on a variety of platforms — as a towed trailer, on a self-propelled land vehicle, or mounted permanently on a ship or in a static air defense gun emplacement. The main functional units are the same in each case, however, and the description that follows relates to the towed trailer version of the system... 

Describe the conditions of waste disposal. Wastes in specified physical and chemical forms and having certain compositions or ranges of compositions of hazardous substances are assumed to be emplaced in certain ways in a disposal site having specified characteristics. The disposal site can be a real location or generic with hypothetical characteristics typical of real sites. The exposure assessment usually assumes that disposal operations have been completed and the site is closed, although the... 

A continuous supply of clay material from the source bed to the shear zone can be maintained, given the necessary plastic properties of the material, if a driving horizontal stress difference between distant parts of the source bed and the immediate vicinity of the fault can be maintained. This requires some mechanism of horizontal stress relief to operate at the fault intersection of a source bed. Preferably, the same mechanism should be capable of resolving the space problem implied by the emplacement of massive clay smears. 

Mechanical equipment used in combat operations to clear mines includes armored vehicles equipped with devices such as plows, flails, and rollers. This equipment clears a path by pushing mines aside or detonating them. It is not effective in rough or rocky terrain and against more advanced, off-route or wide-area mines. However, these advanced mines do not yet make up a large portion of the landmines already emplaced in Third World countries. For these reasons, and because of the potential environmental impact, such as pollution and soil erosion, heavy mechanical equipment is of limited use for wide-area clearance. 

The M8A1 Automatic Chemical Agent Alarm electronically monitors for hazardous levels of nerve agent vapor. While sensitive, it is also prone to false positive responses due to high concentrations of various organic compormds including some pesticides and vehicle exhausts. Operators must be trained to use care in emplacing the device to minimize the chance of false alarms. 

Fig- 2 -9. A battery of dug-in Livens projectors, with one gas shell and its propellant charge shown in the foreground. Electrically controlled salvo firing was the usual mode of operation. Emplacement was a slow process, and it limited the surprise factor for attack. Photograph Chemical and Biological Defense Command Historical Research and Response Team, Aberdeen Proving Ground, Md. 

Overall, the Lasagna process has proven to be a very safe method to treat high concentrations of chlorinated solvent. No contaminated material is removed from the site. All materials are emplaced directly into the contaminated soil by the mandrel system, minimizing exposures to the workers. The contamination is degraded below grade and very httle, if any, vapor reaches the site worker or nearby residents during construction and operation. 

The rows of treatment zones were spaced at 1.5-m intervals between the electrode rows. This was determined to be the most cost-effective spacing based on operational time and installation costs. Extra treatment zone emplacements were made in areas of known or suspected DNAPL levels of TCE. As the contaminated pore water travels by electroosmosis through the treatment zones, the iron filings (zero-valent iron) act to degrade the chlorinated organics. Based on the electroos-motic velocity of 0.5cm/day, the retention time in the 2.5-cm-thick treatment zones is about 120 h. This is more than sufficient time to degrade nearly all TCE to ethane and chloride, especially at the elevated temperature observed. 

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