Nuclear power companies in Japan are working to extend operational periods between mandatory inspections.
In a bid to improve long term performance and profitability, Japanese utility Tokyo Electric Power Company (Tepco) has said it will apply to increase intervals between regular inspections for Fukushima Daini 3, from 13 months to 16 months. The decision on whether to extend the interval will be made by the Nuclear and Industrial Safety Authority, the Japanese regulator, and is due by the end of the plant's next regular inspection in September this year.
Under Japanese regulations the default period between inspections is 13 months, but changes made in January 2009 allow operators to apply to increase this to 18 months. Subject to approval, a five year introductory period would follow, after which the limit could be raised to 24 months between inspections.
In a 12 January statement Tepco said that it believes Fukushima Daini is physically capable of operating for 26 months between inspections, but is applying for the 16 months interval in accordance with the current requirements and to help prevent possible public misgivings at the change. With a fuel and maintenance outage included, the time between inspections is more likely to be 18 months.
Tepco is the second utility to apply for such an extension, after Tohoku Electric Power Company applied for a similar extension – from 13 months to 16 months – for Higashi Dori 1 in November last year. The decision on this unit is due after its next regular inspection in June.
The median capacity factor for Japanese plants is about 70% - compared to over 90% for the best performers worldwide - with the country's inspection requirements a contributing factor to this gap. Most other countries conduct regulatory checks so that utilities can operate their power plants almost all the time that refuelling or major maintenance is not taking place.
Reducing regulatory outages will increase profitability as well as reduce the amount of carbon dioxide produced by fossil fuel alternatives that are stepped up when nuclear plants are not in operation.
Currently about 25% of Japan's electricity comes from nuclear plants, with almost 65% coming from coal, oil and gas. While nuclear's contribution is likely to grow with new plants as well as the return of earthquake-hit units at Kashiwazaki Kariwa, increasing performance at existing power plants will help. Official targets are for 40% of electricity generation to be nuclear by 2018.
Researched and written
by World Nuclear News