USDOE Issues Funding Opportunity Announcement for SMRs

The US Department of Energy (USDOE) issued a draft Funding Opportunity Announcement (FOA) this week, intended to support activities related to the design and licensing of Small Modular Reactors (SMRs), defined as reactors with an electric output of 300MWe or less; which can be manufactured remotely, transported to point of construction, with on-site assembly largely limited to system integration of components for operation.

Importantly, the USDOE is interested in designs with passive safety (e.g., against consequences of a nuclear accident) as well as inherent safety (e.g., against natural catastrophes such as earthquakes, windstorms or floods), in addition to designs with long inter-refueling periods, low capital cost outlays, low maintenance and operating costs, and high proliferation resistance. The stated intention is to support up to 2 reactor designs through the USNRC design and licensing process, with the ability to be deployed ‘expeditiously’ being an important merit criterion. 2022, a decade from now, is the target year for commercial operation.

Proponents may choose to pursue licensing from the USNRC under either 10 CFR 50 or 10 CFR 52. Stakeholders are encouraged to form consortia, and proponents are encouraged to form design-centered working groups (DCWGs) across the supply and value chains e.g., SMR manufacturers, power utilities, local bodies; and the activities funded by USDOE are required to draw at least 50% of their total resources required, from internal sources. The total amount of funding available from USDOE is estimated to be $452 M, subject to Congressional appropriations. The current draft FOA will be issued in final form after feedback from, and consultation with, stakeholders.

IAEA Course on Natural Circulation Phenomena - Harbin, China

The IAEA is conducting a course on Natural Circulation Phenomena and Passive Safety Systems in Advanced Water-Cooled Reactors at the College of Nuclear Science and Technology of the Harbin Engineering University at Harbin in Northern China, July 11-15, 2011.

Several recent advanced reactor designs (both large reactors like the ESBWR and the AP-1000, and integral pressurized water reactor [iPWR] designs in the SMR category, like mPower, NuScale and the newly announced Westinghouse SMR) propose natural circulation systems for decay heat removal. Other evolutionary designs also propose natural circulation convective systems for heat transfer in regular operation. The site of the first AP-1000 units to be constructed anywhere, the Sanmen Nuclear Power Plant (where two AP-1000 units are currently under construction) with planned in-service dates in 2013-14, is in China. China is also planning 1400 MWe and 1700 MWe variant designs based on the AP-1000, with the CAP-1400 said to be in an advanced design stage. Presumably, these will also utilize passive safety systems based on natural circulation, and this strong interest in natural circulation cooling in China is one of the main reasons that the location of this IAEA course is in Harbin.

The agenda for the course comprises both introductory and advanced lectures, by distinguished researchers in the field of natural circulation cooling, including Drs. Jose Reyes, Dilip Saha, Nusret Aksan, and F. D'Auria, among others. Particularly of interest is the lecture by Dr. Reyes on Thursday 14 July on Flow Stagnation in Single and Two-Phase Natural Circulation Loops [literature citation], which will discuss mechanisms which can interrupt natural circulation - for example, in a PWR, loss of heat sink could result in reverse heat transfer in the steam generator, interrupting single phase natural circulation. This and other mechanisms that interrupt both single- and two-phase natural circulation were studied by Dr. Reyes' group at Oregon State University in special thermalhydraulic loops constructed for the purpose. Scaling relationships are critical in understanding the applicability of results obtained from such loops to real reactor systems, and Dr. Reyes also presents a lecture on Integral System Experiment Scaling Methodology, while Dr. Dilip Saha presents a related lecture on Experimental Validation and Database of Simple Loop Facilities. Developing reliability models of passive safety systems utilizing natural circulation is critical to safety analysis of such reactors, and Prof. F. D'Auria will present a lecture on Reliability of Thermalhydraulic Passive Safety Systems. Generally speaking, studies of natural circulation phenomena are complicated by the fact that the driving force is usually quite weak, as compared, for example, to turbulence or friction that may also be present in the flow.