Transactions of the American Nuclear Society 

About: Transactions of the American Nuclear Society is an academic journal. The journal publishes majorly in the area(s): Neutron & Monte Carlo method. It has an ISSN identifier of 0003-018X. Over the lifetime, 8239 publications have been published receiving 31892 citations.

Active control of oxygen in molten lead-bismuth eutectic systems to prevent steel corrosion and coolant contamination

Abstract: There is a strong resurgent interest worldwide in heavy-liquid metals as nuclear coolant and spallation neutron target material. The continuing research and development (R and D) in accelerator-driven systems and accelerator-driven transmutation of waste have brought attention to the lead-bismuth eutectic (LBE) nuclear coolant technology. Around the world R and D organizations are investigating the LBE technology in the areas of materials and corrosion, coolant quality control, thermal hydraulics, and nuclear data. There have also been concerted efforts to develop very long lived core, lead-alloy-cooled, proliferation-resistant, super safe, and transportable reactors. In this paper, the thermodynamic basis for controlling oxygen level in lead-bismuth to prevent steel corrosion and coolant contamination is examined. The operational conditions, including the thermodynamic activity of oxygen, cover-gas oxygen partial pressure, mixtures of H{sub 2} and H{sub 2}O (steam) for obtaining such low oxygen partial pressure, and the voltage signals of one type of oxygen sensors (with solid electrolyte and molten bismuth electrode) are calculated. These results provide the guidance to implement the oxygen control technique. The authors are performing laboratory experiments to verify this understanding and building an LBE material and thermal-hydraulic test facility to further develop LBE technology for accelerator transmutation of wastes applications.

Accident source terms for light-water nuclear power plants

Abstract: This paper presents a discussion of current U.S. Nuclear Regulatory Commission (NRC) activities regarding the proposed revision of accident source terms for light-water nuclear power plants, particularly since the issuance of draft revised source terms in July 1992. The NRC's current reactor site criteria require that an accident fission product release within containment, or [open quotes]source term,[close quotes] be postulated to occur and that its radiological dose consequences be evaluated. The current source term, derived from a 1962 report 2 TID-14844, postulates the instantaneous appearance within containment of 10% of the core inventory of noble gases, 50% of the core inventory of iodine (with half of this assumed to plate out very rapidly on interior surfaces), and 10% of the remaining fission products. This source term has also been used to evaluate other important plant performance requirements, such as control room habitability, postaccident access, and sampling and equipment qualification, and consequently has played an important role in nuclear power plant licensing. Aspects of this source term have long been recognized as being inconsistent with a realistic understanding of severe accident behavior. Because NRC review of advanced reactor designs showed the need for a more realistic understanding of accident mitigation capability,more » it became clear that the current source term should be updated.« less

Risk management guidelines

Abstract: Northeast Utilities (NU) has developed and implemented a comprehensive probabilistic safety assessment (PSA) program in support of nuclear power plant engineering and operations. Included in this program is a formal policy statement on nuclear safety goals; formalized procedures for review of all plant design changes; a formal procedure for prioritizing new projects; and at least level 1 probabilistic safety studies on all four NU-operated nuclear units. A procedure on risk communication to senior management has also been implemented. This procedure was recently amended to provide quantitative guidelines for determining the acceptability of issues affecting risk. The guidelines described are believed to be unique to the utility industry. The guidelines provide consistency and delineation of authority in making risk management decisions. They are also intended to complement, rather than substitute for, other means of determining the acceptability of plant changes and conditions. Implementation of these guidelines illustrates the strong support that NU senior management has for PRA methods.