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Division Spotlight
Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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Latest News
Commercial nuclear innovation "new space" age
In early 2006, a start-up company launched a small rocket from a tiny island in the Pacific. It exploded, showering the island with debris. A year later, a second launch attempt sent a rocket to space but failed to make orbit, burning up in the atmosphere. Another year brought a third attempt—and a third failure. The following month, in September 2008, the company used the last of its funds to launch a fourth rocket. It reached orbit, making history as the first privately funded liquid-fueled rocket to do so.
Azin Behdadi, John C. Luxat
Nuclear Technology | Volume 181 | Number 1 | January 2013 | Pages 157-169
Technical Paper | Special Issue on the 14th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-14) / Fission Reactors; Reactor Safety; Thermal Hydraulics | doi.org/10.13182/NT13-A15764
Articles are hosted by Taylor and Francis Online.
Heavy water moderator surrounding each fuel channel is one of the important safety features in CANDU reactors since it provides an in situ passive heat sink for the fuel in situations where other engineered means of heat removal from fuel channels have failed. In a critical-break loss-of-coolant-accident scenario, fuel cooling becomes severely degraded because of rapid flow reduction in the affected flow pass of the heat transport system. This can result in pressure tubes (PTs) experiencing significant heatup during early stages of the accident when coolant pressure is still high, thereby causing uniform thermal creep strain (ballooning) of the PT in contact with its calandria tube (CT). The contact of the hot PT with the CT causes rapid redistribution of stored heat from the PT to the CT and a large heat flux spike from the CT to the moderator fluid. For conditions where subcooling of the moderator fluid is low, this heat flux spike can cause dryout of the CT. This can detrimentally affect channel integrity if the CT postdryout temperature becomes sufficiently high to result in continued thermal creep strain deformation of both the PT and the CT. The focus of this work is to develop a mechanistic model to predict critical heat flux (CHF) on the CT surface following a contact with its PT. A COMSOL multiphysics model using a two-dimensional transient fluid-thermal analysis of the CT surface undergoing heatup is used to predict the flow and temperature profiles on the CT surface. A mechanistic CHF model is to be proposed based on a concept of wall dry patch formation, prevention of rewetting, and subsequent dry patch spreading.