The final post-Fukushima stage
Brunswick Nuclear safety cited, begins vent hardening
North Carolina's oldest nuclear power plant is back at full power after a late winter, early spring that included beginning the final stage of the seven-year post-Fukushima modification effort.
Along the way, a note from the Nuclear Regulatory Commission stating the Brunswick Nuclear Plant operated safely during 2016 and met commission requirements, ending the year with no inspection findings or performance indicators outside the normal band.
Last week, NRC staff journeyed to the nuclear power plant on Southport's north side for an open house to discuss last year's safety performance.
This week an NRC note stating the other eastern Tar Heel State nuclear power plant operated safely during 2016 and met NRC requirements.
An open house is planned for May 22 in Holly Springs, NC To discuss the 2016 safety performance of the Harris Nuclear Plant located near New Hill.
Early the day following the Southport open house, Duke Energy's daily Power Reactor Status report to the NRC showed both Brunswick reactors at 100 percent power for the first time since early February.
A Coast-Down to Refueling, Vent Hardening
On February 5, Unit 2 – the oldest of the plant's two reactors by a year -- began a six week coast-down to its 21st biannual refueling, a four week session that featured Phase I of the plant's final post-Fukushima modification.
After a tsunami damaged the Fukushima I Nuclear Power Plant in March 2011, operators were unable to successfully vent the Mark I containment building, inhibiting efforts to cool the boiling water reactor (BWR) core.
Based on the NRC's Lessons-Learned Task Force's recommendations in the second half of 2011, the commission issued orders in March 2012 to make modifications in operating U.S. reactors, most of which have been completed.
This year and next, operators of 29 GE BWRs with Mark I or Mark II containment buildings – including Brunswick Nuclear – are completing Phase I of a retrofit designed to allow operation of the vents under a range of plant conditions, including a prolonged onsite and off-site loss of power and inadequate containment building cooling.
One power plant with the problem vents, the Pilgrim nuclear power plant in Massachusetts, was granted an extension until December 2019, making complying moot given Entergy said it would close the BWR June 2019, due to a negative economic environment.
Brunswick Unit 2 is one of 14 reactors to have completed Phase I vent hardening, according to NRC spokesman Scott Burnell. Five more are scheduled to complete the retrofit this year, and ten – including Brunswick Unit 1 – have set 2018 completions.
Four U.S. BWRs – Exelon's Clinton Power Station in central Illinois; FirstEnergy's Perry Nuclear Power Plant, northeast of Cleveland on Lake Erie; and Entergy's Grand Gulf Nuclear Station in Mississippi and River Bend Station in Louisiana – have Mark III containments which have different approaches to controlling pressure within containment, Burnell noted.
All 29 reactors, located at 18 plant sites, are scheduled to complete Phase II of the vent hardening retrofit by 2019, with some starting the effort this fall, NRC spokeswoman Maureen Conley said.
Duke Energy, which operates 11 reactors at six sites in the Carolinas, still expects the post-Fukushima modifications to cost $600 million, spokeswoman Karen Williams said. The figure was first released when the company outlined its plans to the NRC in November 2013.