Summary
Currently about 11% of the world's energy is produced in nuclear power plants; this implies the processing of uranium in order to enrich it to be suitable for “burning” in a nuclear reactor. Besides other environmental and monetary costs involved in the whole nuclear fuel cycle, the enrichment process has the disadvantage of producing depleted uranium as a sub‐product that has no wide use and is essentially stockpiled. One strategy to deal with this issue is to design a nuclear reactor that can run mostly on depleted uranium by breeding its own fissile fuel from it. Even though this concept could sound innovative or new, the truth is that it has been in the thought of the nuclear engineers since the 50s. In the present paper, the breed & burn (B&B) reactor concept is reviewed, as well as its origins, evolution up to present, and its main technical features. The objectives of this review are as follows: (1) to summarize the history of the development of B&B reactors, (2) to compare different B&B concepts based on a systematic approach under selected technical features, and (3) to bring out current trends and future directions on this technology. It is expected that this review will help the nuclear engineering community in general, and newcomer researchers in the field, to get an overview about the B&B reactors and how to direct a research in this direction.
IntroductionLeiomyosarcomas (LMS) involving the inferior vena cava (IVC) is a clinically rare entity, accounting for approximately 0.5% of all adult sarcomas.Case presentationA 67-year-old male presented to the emergency department with mild back and lower abdominal pain. During the workup, a computed tomography scan without contrast showed an area of decreased attenuation within the liver adjacent to the intrahepatic IVC. Magnetic resonance imaging confirmed the involvement of the retro-hepatic IVC; biopsy confirmed the diagnosis of LMS. Given the location of the involvement of the retro-hepatic IVC, liver explantation was deemed necessary for adequate tumor resection. The superior extension of the tumor toward the heart necessitated Cardio-Pulmonary (CPB). The patient successfully underwent a complex surgical procedure involving liver explantation with ex vivo back-table resection of the retro-hepatic LMS, replacement of the retro-hepatic vena cava with a ringed Gore-Tex graft, liver re-implantation, and hepatic vein-atrial reconstruction under cardiopulmonary bypass. There were no intraoperative or post-op complications.DiscussionThe role of vascular reconstruction of the IVC varies depending on the level and extent of the tumor, with options ranging from primary repair, ligation, or reconstruction dictated. Surgical resection with negative margins remains the treatment of choice due to the lack of efficacy of adjuvant therapies. Importantly, liver explantation offers a chance for complete surgical resection and reconstruction. Similarly, the complex nature of the tumor necessitated a pioneering approach involving direct hepato-atrial venous anastomosis.ConclusionTo the best of our knowledge, this is the first reported case in which the hepatic veins were anastomosed directly to the right atrium while also replacing the native vena cava with a separate graft.
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