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November 30, 2011

China connects another new nuclear reactor and Progress on the pebble bed reactor and other new reactors

1. Unit 4 of China National Nuclear Corporation's (CNNC's) Qinshan Phase II nuclear power plant was connected to the grid on 25 November – the second Chinese reactor to be connected this year. It is expected to enter commercial operation early in 2012. The reactor, a CNP-600, is a two loop domestic design rated at 650 MWe. It has taken about five years to build, with first concrete for the unit poured in January 2007.

Another Chinese reactor, Ling Ao unit 4, was connected to the grid on 3 May while unit 1 of the Ningde nuclear power plant began its cold test functions on 28 November and should enter service next year. With the addition of Qinshan Phase II unit 4, the total number of operating Chinese reactors stands at 15.

2. China's HTR-PM (high temperature pebble bed) began construction in mid 2011. This will have twin reactors, each of 250 MWt driving a single 210 MWe steam turbine. The fuel is 9% enriched (520,000 elements) giving 80 GWd/t discharge burn-up.

The projected cost is US$ 430 million (but later units falling to US$1500/kW with generating cost about 5 ¢/kWh). Start-up was scheduled for 2013, now 2015. The HTR-PM rationale is both eventually to replace conventional reactor technology for power, and also to provide for future hydrogen production. INET is in charge of R&D, and is aiming to increase the size of the 250 MWt module and also utilize thorium in the fuel. Eventually a series of HTRs, possibly with Brayton cycle directly driving the gas turbines, would be factory-built and widely installed throughout China.




3. Hyperion Power Generation

The Hyperion Power Module is a 70 MWt/25 MWe lead-bismuth cooled reactor concept using 20% enriched uranium nitride fuel. The reactor was originally conceived as a potassium-cooled self-regulating 'nuclear battery' fuelled by uranium hydridem. However, in 2009, Hyperion Power changed the design to uranium nitride fuel and lead-bismuth cooling to expedite design certification. This now classes it as a fast neutron reactor, without moderation. Hyperion claims that the ceramic nitride fuel has superior thermal and neutronic properties compared with uranium oxide. It would be installed below ground level.

Hyperion has said it plans to build a prototype by 2015, possibly with uranium oxide fuel if the nitride is not then available.

4. Russian SVBR-100

A smaller and newer Russian design is the Lead-Bismuth Fast Reactor (SVBR) of 75-100 MWe, from Gidropress. This is an integral design, with the steam generators sitting in the same Pb-Bi pool at 440-495°C as the reactor core. It is designed to be able to use a wide variety of fuels, though the reference model uses uranium enriched to 16.5%. With U-Pu MOX fuel it would operate in closed cycle. Refuelling interval is 7-8 years. The SVBR-100 unit of 260-280 MWt would be factory-made and shipped as a 4.5m diameter, 7.5m high module, then installed in a tank of water which gives passive heat removal and shielding. A power station with 16 such modules is expected to supply electricity at lower cost than any other new Russian technology as well as achieving inherent safety and high proliferation resistance. (Russia built seven Alfa-class submarines, each powered by a compact 155 MWt Pb-Bi cooled reactor, essentially an SVBR, and 70 reactor-years operational experience was acquired with these.)

The plan is to complete the design development by 2017 and put on line a 100 MWe pilot facility by 2020, with total investment by Russkiye Mashiny of RUR16 billion ($585 million). The site is to be at the Research Institute of Atomic Reactors in Dimotrovgrad, though earlier plans were to put it Obninsk. The SVBR-100 could be the first reactor cooled by heavy metal to be utilized to generate electricity. It is described by Gidropress as a multi-function reactor for power, heat or desalination.

An SVBR-10 is also envisaged, with the same design principles, a 20-year refuelling interval and generating capacity of 12 MWe, though it too is a multi-purpose unit.

5. Travelling wave and standing wave reactors

In mid 2011 Terrapower changed the design to be a standing wave reactor, since too many neutrons would be lost behind the travelling wave of the previous design and it would not be practical to remove the heat efficiently. A standing wave design would start the fission reaction at the centre of the reactor core, where the breeding wave stays, and operators would move fresh fuel from the outer edge of the core progressively to the wave region to catch neutrons, while shuffling spent fuel out of the centre to the periphery. As the wave would be surrounded by new fuel in most directions, more neutrons would be utilized compared with a traveling wave scheme. The “shuffling” would be conducted while the reactor is operating. Such a reactor could reach a fuel burn-up of “up to 30%” and run “40 to 60 years” without refueling, according to Terrapower. It would still use sodium as coolant. A demonstration TP-1 of 500 MWe was planned for China, Russia or elsewhere, to operate from 2020. A commercial version would be 1150 MWe. Another report says a 100 MWe demonstration plant is planned for 2016 construction start and operation from 2020

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