The Korean Atomic Energy Research Institute (KAERI) has announced two new technological developments - a remote-controlled robot for refuelling pressurized heavy water reactors, and an indigenous reactor safety analysis system for pressurized light water reactors - that have the potential to improve reactor safety and operating efficiency.
Pressurized heavy water reactors (PHWRs) require pressure tubes containing nuclear fuel to be changed on a daily basis. This is currently done by an automated fuel loading machine, but any breakdown in the system can result in a reactor shut down, as radiation levels mean that engineers cannot go near the fuel changing chamber when the reactor is operating. "The repairs and changing of the pressure tubes can take about 10 hours and can result in considerable monetary loss," according to Jung Seung-ho, head of KAERI's nuclear robot lab.
The Kaerot M-3 robot is a fully mobile, remote-controlled robot that can change the fuel of a PHWR in a fifth of the time taken by conventional fuel loading machines. It took four years, and cost about 3 billion Won ($3.3 million), to research and develop. Weighing in at 370 kg, it has a mast-like fuel installer that can be extended to 9.5 m to change pressure tubes, and has been tested in the Wolsong nuclear power plant. KAERI has said it may look to export robots to other countries using PHWRs.
In a separate development, KAERI researchers have developed an indigenous safety analysis system that can be used in all Korea's pressurized light water reactors (PWRs) as well as in the next-generation units currently being developed.
The Multi-Purpose Integrated Assessment Code for Severe Accidents (MIDAS) aims to eliminate fundamental design or operational flaws that could potentially cause serious nuclear accidents. It is based on the US Nuclear Regulatory Commission's Methods for Estimation of Leakages and Consequences of Releases (MELCOR) code, a fully integrated code that models the progression of severe accidents in PWRs that is used around the world to check for serious problems in design and operating systems.
MIDAS, which took seven years to develop, includes the latest data on accidents and should give the user an improved ability to deal with possible accidents. "MIDAS has a graphic-user interface to make it easier to input and pull data, and run various safety simulations", said Park Seon-hee, a researcher at KAERI.
South Korea has 20 operating nuclear reactors, of which 16 are PWRs and 4 are PHWRs. Three further units are under construction, with construction due to start on a further five units within the next four years.
Korean Atomic Energy Research Institute (KAERI)
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