Five cracks found in a reactor head at the V.C. Summer nuclear plant in Jenkinsville, SC, are under repair, but S.C. Electric & Gas (SCE&G) officials said the company plans to replace the aging vessel head in 2017.
The five cracks, uncovered in inspections last week during a routine plant shutdown, did not penetrate the wall of the reactor head, the utility said, and posed no danger to workers at the site or the public.
Located about 25 miles north of Columbia, V.C. Summer in Fairfield County has been in shutdown – a regularly scheduled outage for maintenance and refueling – since April 4.
The plant undergoes such an outage, which lasts an average of 46 days, every 18 months.
The five areas SCE&G identified for repair were small and virtually undetectable by normal eyesight, officials with the chief subsidiary of Cayce-based energy giant SCANA Corp. said. Robotic inspection and ultrasound testing verified the presence of the cracks.
“These pre-emptive inspections and repairs are designed to detect and correct even the slightest imperfections to prevent an actual problem,” said James Patrick Flynn, an SCE&G spokesman, in response to questions about the discovery of new cracks. “It is not unusual to detect additional small indications (cracks) after 18 months of operation. The detection technology allows us to catch these tiny indications early before they become problems.”
The discovery and repair of the new cracks should not significantly impact the duration of the maintenance outage, Flynn said.
During an outage at the Summer plant, SCE&G, one of the largest utilities in the state, depends on its other generating facilities to produce electricity for its 678,000 electrical customers.
V.C. Summer’s 966-megawatt reactor has been generating electricity since January 1984. In that time, the SCANA-owned subsidiary said the plant has undergone 21 routine maintenance and refueling outages and would undergo two additional outage shutdowns under the 2017 replacement time frame.
SCE&G is building two new reactors at the V.C. Summer plant in a nearly $10 billion project. They are among only a handful of new reactors permitted in recent years. The new reactors will use a different design and are going up in conjunction with Santee Cooper, the state-owned utility. Those reactors should go online in late 2017 and 2018, respectively.
In the fall of 2012, the Summer plant’s previous outage, inspections turned up flaws in four welded holes in the reactor vessel head and those problems ended up repaired, the company said.
Even before the current inspections, SCE&G said its long-range plans were to replace the reactor vessel head.
“We ordered a new reactor vessel head before the start of our current outage,” Flynn said. “Because of the highly specialized production process, reactor vessel heads take years to be produced.”