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A trip abroad
Hash Hashemian president@ans.org
In my August column in Nuclear News, I reflected on the importance of ANS’s annual conferences for bringing together our nuclear community at the national level. In September, after speaking at Tennessee’s Nuclear Opportunities Workshop, I focused my NN column that month on the value of state-level conferences.
Also in September, alongside ANS Executive Director/CEO Craig Piercy, I shifted my focus to another key front in nuclear collaboration, the international stage, by attending the General Conference of the International Atomic Energy Agency in Vienna.
The timing of the IAEA’s General Conference could not have been better; it took place the same week the U.S. and U.K. kicked off a new wave of transatlantic partnerships in the nuclear sector between both government and industry. This fortuitous overlapping gave us a timely and concrete reminder of international collaboration’s unparalleled benefits.
The General Conference was an expectedly busy event. To cover as much ground as possible, Piercy and I took turns attending either the U.S. delegation meetings with other countries or the General Assembly of the IAEA, where the American Nuclear Society has a seat among other critical nongovernmental organizations.
We listened to presentations by several of the 180 IAEA member states, including, of course, the United States. Aside from ANS, the U.S. presence at the conference included U.S. Secretary of Energy Chris Wright, NRC Chair David Wright, and DOE Assistant Secretary of Nuclear Energy Ted Garrish.
U.S. representation was further bolstered by an industry delegation that included 65 participants from 32 companies, many of whom used the opportunity to report progress on their plans for the international expansion of their nuclear fleets. Meetings of that industry delegation were coordinated by the Nuclear Energy Institute.
Aside from the main conference, Piercy and I also attended the embedded meetings of the International Nuclear Society Council. INSC exists to facilitate knowledge-sharing and collaboration between 18 different member nuclear societies from around the world.
The INSC meetings within the General Conference brought together the presidents and senior members of those societies to give presentations and explore new opportunities. I made a presentation on the state of nuclear in North America, covering the latest developments and deployments in the U.S. and Canada.
This presentation emphasized the new nuclear lift in the U.S. that is being heavily supported by the Trump administration. I recapped the four executive orders issued by President Trump in May, the recent momentum at the DOE, and how these changes are capitalizing on a broader groundswell in both industry development and public support.
I also pointed out the success of our neighbor Canada in progressing on the first water-cooled small modular reactor in North America using BWRX-300 technology, which was supplied by an American firm and international partners—a perfect symbol of the value of global nuclear collaboration.
In all, I have now represented ANS at the state, national, and international levels, gaining useful insight into the work that needs to be done at each. From this vantage point, it’s clear to me that the path forward from the country to the globe is to, above all else, keep working together and supporting each other to bring about the next age of nuclear.
Kifah J. Takrouri, John C. Luxat, Mohamed S. Hamed
Nuclear Technology | Volume 208 | Number 3 | March 2022 | Pages 520-538
Technical Paper | doi.org/10.1080/00295450.2021.1935164
Articles are hosted by Taylor and Francis Online.
Rewetting a hot dry surface is the establishment of wet contact between the hot surface and a liquid at a lower temperature. Rewetting occurs after destabilizing a vapor film that exists between the hot surface and the liquid. Situations involving rewetting heat transfer are encountered in a number of postulated accidents in Canada Deuterium Uranium (CANDU) reactors, such as rewetting of a hot dry calandria tube in a critical break loss-of-coolant accident (LOCA). It is also encountered in improving metals’ mechanical properties in metallurgical industries. One of the important parameters in rewetting cooling is the rewetting delay time, which is the time interval from starting to cool the surface by the liquid to the establishment of the wet contact. Determining the rewetting delay time is very important for limiting the extent of core damage during the early stages of reactor severe accidents and is essential for predicting the period after which the coolant effectively cools an overheated core. If the rewetting delay time is relatively long, an escalation in the calandria surface temperature can occur, and if the temperature was not reduced by the establishment of the wet contact, this may lead to failure of the fuel channel. Although there is increasing interest in literature in estimating the rewetting delay time of hot flat surfaces, very limited studies exist on rewetting of curved surfaces, such as tubes. In this study, experimental tests were carried out to measure the rewetting delay time at the stagnation point of hot horizontal tubes cooled by a vertical rectangular water jet. The tubes were heated to initial temperatures between 400°C and 740°C, then rapidly cooled to the jet temperature. The two-phase flow behavior was visualized using high-speed imaging, and the moment at which the vapor film collapses was captured. In addition to studying the effect of initial surface temperature on the delay time, effects of water subcooling in the range 15°C to 80°C and jet velocity in the range 0.17 to 1.43 m/s were studied and a correlation for the delay time was developed and validated. The delay time was found to strongly increase by increasing initial surface temperature and surface curvature and by decreasing water subcooling and jet velocity. The effects of solid material and tube wall thickness were also studied.
