A CANDU core is composed of lots of fuel channels of a pressure tube type which creates an independent flow passage different from that of a LWR. Hence, most of the aging effects for a CANDU’s operating performance originate from a crept pressure tube as its operating years proceed. Since the early 1990’s, Korea Atomic Energy Research Institute (KAERI) and Atomic Energy of Canada Limited (AECL) have cooperated to develop, verify, and demonstrate an advanced CANDU fuel, called a CANFLEX-NU (CANdu FLEXible-Natural Uranium) fuel, which has been specially designed so as to compensate for a deterioration of the heat transfer rate in a crept pressure tube and also to enhance the safety margin of it by a reduction of the maximum linear element power of a fuel bundle. Now, a CANFLEX-NU fuel is ready to be commercialized in a CANDU-6 because its design and demonstration irradiation have been completed in both of Korea and Canada. Recently, some CANDU plants are being refurbished as they are approaching their life time. One of the refurbished CANDU’s is Wolsong Unit 1 in Korea. It has been operated for 25 years and the operating power at the present time is less than 90% of a full power because of a reduction of the margin for the ROP trip set point. The most appropriate way, up-to now, to overcome such a power de-rating due to a crept pressure tube is the introduction of a CANFLEX-NU fuel into a CANDU. Before commercializing a CANFLEX-NU fuel in the Wolsong Units, it was required to estimate the economic benefit analysis for a CANFLEX-NU fuel in the Wolsong Units because the Uranium price at present is very different from that during the development phase of the CANFLEX-NU fuel. The present paper proposes an economic evaluation model for a CANFLEX-NU fuel in the Wolsong Units and its result for a CANFLEX-NU fuel are compared with that for a 37-element fuel. It was found that the introduction of a CANFLEX-NU fuel into the Wolsong units would have economical benefits due to a better operating performance even where it is assumed that the fuel fabrication cost of a CANFLEX-NU fuel is 1.4 times that of a 37-element fuel. Once the final results are obtained, they will be used as one of important parameters to determine the introduction of a CANFLEX-NU fuel in the Wolsong Units, or not.

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