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Division Spotlight
Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Nuclear Science and Engineering
August 2024
Nuclear Technology
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Latest News
Vogtle-3 shuts down for valve issue
One of the new Vogtle units in Georgia was shut down unexpectedly on Monday last week for a valve issue that has since been investigated and repaired. According to multiple local news outlets, Georgia Power reported on July 17 that Unit 3 was back in service.
Southern Company spokesperson Jacob Hawkins confirmed that Vogtle-3 went off line at 9:25 p.m. local time on July 8 “due to lowering water levels in the steam generators caused by a valve issue on one of the three main feedwater pumps.”
Daniel A. Mattes, Da?istan ?ahin (NIST)
Proceedings | Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technolgies (NPIC&HMIT 2019) | Orlando, FL, February 9-14, 2019 | Pages 733-735
Three gaseous effluent monitor systems collect air within the National Bureau of Standards Reactor (NBSR) confinement building. The normal air channel measures air sampled from the normal air, process room air, and emergency ventilation systems. The irradiated air channel measures air sampled from the irradiated air, confinement hoods, and emergency recirculating systems. All the collected air is combined and re-measured by the stack channels. Each of these channels provides radiation alarms and protective safety actions. Furthermore, these systems provide redundant protection against personnel exposure and uncontrolled release of radioactive material to the environment. The normal air channel continuously monitors the exhaust air leaving the building for gaseous radioactive release. A vacuum pump draws air, from a sample tap in the normal air duct downstream of the HEPA filters, through a shielded detector chamber. The existing analog system utilizes a Geiger-Mueller probe sensitive to the beta-gamma radiation emitted by the gaseous airborne radioactivity (predominately AR-41). A pre-amplifier connects the detector to the counting circuits in the log-count ratemeter. The ratemeter has alarm outputs that actuate the major scram circuits and the annunciator system. The building exhaust activity high alarm alerts the reactor operator to a high activity condition in the normal air monitoring system. The new system selected to replace the normal air channel is comprised of a digital ratemeter and scintillation detector which, based on the company provided documentation, has been through a rigorous analysis for use in safety-related nuclear systems. As utilized at the NBSR, the unit does not have digital communication and is used for its intended purpose without modification to the ratemeter. The digital unit does not change how the design function of the normal air channel is performed, i.e. the new unit measures radioactive isotope concentrations in the gas samples using a radiation detector. The new radiation detector is similar with regards to radiation detection capabilities and has a greater dose rate range capability compared to the existing detector. A detailed assessment of existing and the new detector capabilities was conducted to identify differences. The most significant deviation was that the new normal air monitoring channel introduces a digital logic for the quantification of radiation levels. The use of digital equipment (hardware and software) therefore has the potential of creating a new type of malfunction that was not previously considered and needed to be analyzed to determine the impact on the pertinent design functions as a safety system.