The operation rate of Korea’s nuclear power plants fell to a 25-year low this year at about 75 percent, data showed Sunday.

The dip in the operation rate apparently came as a result of a series of shutdowns of nuclear power plants due to mechanical problems or renewal.

According to a report from the state-run Korea Electric Power Corp., the nation’s 23 nuclear power plants produced 115 million megawatt-hours of electricity from January to October, operating at 75.2 percent of total operation capacity.

It is the first time since 1990 for the operation rate to dip to below 80 percent. This year marked the lowest level since 73.0 percent in 1988. Korea launched the commercial operation of its first nuclear power plant in 1978.

Industry watchers said it was unlikely that the rate will rise by year-end as six of the 23 nuclear plants have been suspended due to malfunction or checks on the use of substandard parts.

Three nuclear plants, including Shin-Kori 1, which are undergoing maintenance to replace faulty parts, are expected to resume operations as early as the end of this month.

From 2000 to 2011, the nation’s nuclear power plants operated at 90 percent capacity and above, and dropped to 82.3 percent last year.

The nation’s 75 percent operation rate this year is lower than the global average of 78.9 percent recorded in the first half of 2011. There are 437 nuclear power plants in operation worldwide.

To avoid a possible blackout, the government recently announced a package of measures to cut power consumption, including an increase in electricity fees for both individuals and companies.

By Kim Joo-hyun (jhk@heraldcorp.com)