Nuclear power plant Krško back online after emergency repair

Parts of pipelines on both sides of the reactor vessel in the Krško nuclear plant were replaced as a precaution due to a leakage detected on the reducer section in early October. The facility was reconnected to the power network and its capacity utilization is being gradually increased.

The Krško nuclear power plant was resynchronized with the electricity grid after it was preventively shut down on October 6 due to a leak. Slovenia’s power system stability was put under an additional test with an outage of unit 6 in the Šoštanj coal-fired power plant last week because of a malfunction in the transportation of slag from the boiler. The other unit wasn’t affected.

Both facilities came back online on November 17. Combined, the nuclear and thermal power plant account for two thirds of the country’s domestic electricity output. It should also be noted that Slovenia covers 30% of its power consumption from imports.

Regular overhaul due in April

Krško was relaunched with a capacity utilization rate of 28%, which is being gradually increased, according to its operator NEK. It is a joint venture of Slovenian government-controlled utility GEN energija and Croatia’s Hrvatska Elektroprivreda (HEP Group).

Krško has 696 MW in capacity. It is scheduled for an overhaul in April. Slovenia is planning to build another nuclear power plant.

Westinghouse handles repair

As for the leakage, detected on October 4, the hole was within the primary cooling circuit, in the reducer section of the pipeline. It was on a high-pressure safety injection system, which is one of the emergency core cooling systems.

Westinghouse, the original designer and equipment supplier, repaired the malfunction, helped by domestic companies. Sections of pipelines on both sides of the reactor vessel were replaced until the check valves.

All 121 fuel elements were transferred to the spent fuel pool to enable the repair.

NEK said it is already contracting metallographic research and thermohydraulic and mechanical analyses to determine and analyze the cause of the failure. It plans to complete the examinations within one year.