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Division Spotlight
Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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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INL’s new innovation incubator could link start-ups with an industry sponsor
Idaho National Laboratory is looking for a sponsor to invest $5 million–$10 million in a privately funded innovation incubator to support seed-stage start-ups working in nuclear energy, integrated energy systems, cybersecurity, or advanced materials. For their investment, the sponsor gets access to what INL calls “a turnkey source of cutting-edge American innovation.” Not only are technologies supported by the program “substantially de-risked” by going through technical review and development at a national laboratory, but the arrangement “adds credibility, goodwill, and visibility to the private sector sponsor’s investments,” according to INL.
Nobuyuki Fujita, David A. Rice
Nuclear Technology | Volume 93 | Number 1 | January 1991 | Pages 36-46
Technical Paper | Nuclear Reactor Safety | doi.org/10.13182/NT91-A34516
Articles are hosted by Taylor and Francis Online.
The reactor coolant system (RCS) water level is reduced during each refueling at some plants. Decreasing the level below the top of the loop piping (midloop operation) may be necessary to work on unisolable RCS loop components. A loss of residual heat removal (RHR) under these conditions can be serious due to the reduced water inventory, air in the RCS, and openings in the RCS loops. Under certain conditions, a loss of RHR could lead to rapid core uncovery and potential fuel damage. Core boiling due to a loss of RHR during midloop operation has received little attention until recently. The transient involves complex phenomena induced by core boiling, such as inventory loss from RCS openings and differences between the downcomer and upper plenum water levels, with the reactor vessel acting like a manometer. These phenomena cannot be easily evaluated without a versatile thermal-hydraulic computer code such as RETRAN. Yankee Atomic Electric Company’s RETRAN analysis of these phenomena reveals that the time to core uncovery is shortened by the loss of coolant through RCS openings and the manometer behavior of the reactor vessel water level. This analysis points out some limitations in applying the RETRAN code to this transient. However, the results are confirmed by a Westinghouse report issued after the completion of this analysis.