NuScale upper module mock-up completed

Posted by World Nuclear News on 31 March 2015 in WNN

NuScale Power has completed fabrication and assembly of a full-scale upper module mock-up of its NuScale small modular reactor (SMR).

The major components of the mock-up are: the upper portion of the containment vessel; the reactor vessel head; major piping (including steam and feedwater); the control rod drive mechanisms; major values (including isolation valves); and, the module access platform.

NuScale said the availability of a full-scale mock-up will give its engineers “important insights into the inspection and maintenance activities that are essential to plant operation.” This will help in supporting radiation protection planning to minimize exposure time for refuelling and maintenance workers, it noted. The mock-up will also support customer and regulator inquiries regarding reactor module configuration.

NuScale chief operating officer and chief nuclear officer Dale Atkinson said, “The fabrication of this full-scale upper module mock-up is an important step in the continued support of our reactor design. It provides our engineers with an important opportunity for in-service inspection evaluations which are scheduled to begin in May.”

A full-scale, first-of-a-kind helical coil steam generator (HCSG) for use in NuScale’s SMR is currently undergoing performance tests in Italy. That component will convert nuclear heat into process steam in the reactor.

NuScale’s self-contained SMR design houses the reactor core, pressuriser and steam generator inside a single containment vessel. It relies on gravity, not pumps, to circulate the water in the primary circuit up through a riser above the core and down through the HCSG, which as its name suggests contains tubes in a spiral configuration. After passing through the HCSG, the cooled water is pulled down by gravity to the bottom of the reactor pressure vessel where it is drawn through the core again. A single module can generate 50 MWe (gross) of electricity and is just under 25m in length, 4.6m in diameter and weighing around 450 tonnes. A power plant could include as many as 12 NuScale modules to produce as much as 600 MWe (gross).

In December 2013, the US Department of Energy selected NuScale’s SMR to receive federal funding for up to half of the cost of developing, licensing and commercialising the reactor.
NuScale plans to apply in the second half of 2016 for design certification by the US Nuclear Regulatory Commission. It envisages the first planned combined construction and operating licence (COL) application will be submitted in 2017 by the Utah Associated Municipal Power Systems Carbon Free Power Project, with the project commercially operational in late 2023.