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Lost circulation events continue to plague drilling operations. Severe lost circulation can result in complete loss of the hole along with drilling equipment. When attempting to stop massive losses, rapid preparation and placement of a lost circulation treatment will improve the frequency of successful application. A fiber pill formulation has been developed to address common operational concerns that exist with current lost circulation pill procedures. The one-sack product is designed for rapid mixing and pumping with a minimum of equipment. This product does not require any activators, retarders, set time calculations, or temperature activation. Laboratory testing has demonstrated the ability of the fiber pill slurries to rapidly dewater/de-oil and form a sealing plug. Testing also indicates that the fiber product formulated as a weighted pill with barite will form a plug with measurable compressive strength. The fiber product can be used with a wide range of fluids including freshwater, brines, and base oils. The product, which meets environmental requirements for use in the Gulf of Mexico, can be rapidly mixed and pumped on location using standard rig equipment. The fiber formulation is compatible with all mud systems and is easily removed with standard solids control equipment. This new approach to control severe losses has been successfully applied in several field tests. A few of these field applications will be discussed in detail.

Advanced nuclear fuel cycle concept is interested in reducing separations to a simplified, one-step process if possible. This will benefit from the development of a one-step universal getter and sequestration material so as a simplified, universal waste form was proposed in this project. We have developed a technique combining a modified sol-gel chemistry and electrospinning for producing ultra-porous ceramic nanofiber membranes with controllable diameters and porous structures as the separation/sequestration materials. These ceramic nanofiber materials have been determined to have high porosity, permeability, loading capacity, and stability in extreme conditions. These porous fiber membranes were functionalized with silver nanoparticles and nanocrystal metal organic frameworks (MOFs) to introduce specific sites to capture gas species that are released during spent nuclear fuel reprocessing. Encapsulation into a durable waste form of ceramic composition was also demonstrated.

The current waste management strategy for spent nuclear fuel (SNF) mandated by the US Congress is the disposal of high-level waste (HLW) in a geological repository at Yucca Mountain. Ongoing efforts on closed-fuel cycle options and difficulties in opening and safeguarding such a repository have led to investigations of alternative waste management strategies. One potential strategy for the US fuel cycle would be to make use of fuel loadings containing high concentrations of transuranic (TRU) nuclides in the next-generation reactors. The use of such fuels would not only increase fuel supply but could also potentially facilitate prolonged operation modes (via fertile additives) on a single fuel loading. The idea is to approach autonomous operation on a single fuel loading that would allow marketing power units as nuclear batteries for worldwide deployment. Studies have already shown that high-temperature gas-cooled reactors (HTGRs) and their Generation IV (GEN IV) extensions, very-high-temperature reactors (VHTRs), have encouraging performance characteristics. This paper is focused on possible physics features of TRU-fueled VHTRs. One of the objectives of a 3-year U.S. DOE NERI project was to show that TRU-fueled VHTRs have the possibility of prolonged operation on a single fuel loading. A 3D temperature distribution was developed based on conceivable operation conditions of the 600 MWth VHTR design. Results of extensive criticality and depletion calculations with varying fuel loadings showed that VHTRs are capable for autonomous operation and HLW waste reduction when loaded with TRU fuel.

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