The two new units at the V.C. Summer site in South Carolina are finally beginning to take physical shape and are scheduled to be online within the next four to six years. Given the retirement plans for coal-fired generation in the same service territory, that new capacity may become available just in time.
On Mar. 30, 2012, South Carolina Electric & Gas Co. (SCE&G), principal subsidiary of SCANA Corp., and Santee Cooper, South Carolina’s state-owned electric and water utility, received approval for combined construction and operating licenses (COLs) from the Nuclear Regulatory Commission (NRC) for the V.C. Summer Nuclear Station (VCSNS) Units 2 and 3. The new units will be constructed near Jenkinsville, S.C., in Fairfield County, approximately 26 miles northwest of Columbia. One month earlier, the NRC had approved two COLs for Southern Nuclear’s Plant Vogtle Units 3 and 4 in Georgia ( POWER, “Vogtle Gets Green Light,” May 2012).
The VCSNS process started almost four years to the day in 2008, when SCE&G submitted its application in accordance with 10 CFR Part 52 (Licenses, Certifications, and Approvals for Nuclear Power Plants) for two 1,107-MW Westinghouse AP1000 advanced pressurized water reactor (APWR) units. The AP1000 features proven technology, innovative safety systems, and modular construction. Activities that had to be done in a specific sequence in the past are now performed in parallel, similar to ship building, thus reducing the construction schedule. The NRC-certified design requires 50% fewer safety-related valves, 80% less safety-related piping, and 85% less control cable. Its simplified design should make the new plants easier and less expensive to build, operate, and maintain.
To support the COL, the Final Environmental Impact Statement and Final Safety Evaluation Report were issued in April and August 2011, respectively. The total projected cost for both units is $9 billion. Unit 2 is expected to come online in late 2017 or early 2018, followed by Unit 3 about a year later. The COL is valid for 40 years and can be renewed for an additional 20 years. The application utilized, to the extent practical, the standard content identified in the Final Safety Analysis Report contained in Tennessee Valley Authority’s Bellefonte Units 3 and 4 application. The Bellefonte application was developed by NuStart Energy Development LLC as the AP1000 reference plant application.
The Need for Electricity
The two new units will undeniably be needed. Currently, SCE&G’s established reserve margin target is 12% to 18% of forecasted peak demand. If the nuclear plants are not built, the company’s reserve margin will decline to 2% by 2016 and –3.9% by 2019.
Contributing to this drop, SCE&G has plans to retire up to six coal-fired units at three locations by the end of 2018 as part of its annual integrated resource plan. The units range in age from 45 to 57 years and are SCE&G’s oldest and smallest coal-fired units. In addition, the U.S. Environmental Protection Agency in recent years has issued a series of increasingly stringent regulations targeting coal-fired plants. Since 2008, SCE&G has installed more than $600 million in environmental equipment at its largest coal-fired power plants, significantly reducing emissions of sulfur dioxide, nitrogen oxides, and mercury. However, the company determined that adding costly environmental control equipment to these older plants to ensure compliance with the new regulations is not cost-effective.
SCE&G is creating a diverse energy system that can perform best in the widest range of conditions over the coming decades. By adding nuclear generation, SCE&G’s generation mix in 2019 will be 31% nuclear, 27% coal, 28% natural gas, and 14% hydro/biomass, and it will reduce carbon emissions by 54% compared to 2005 levels. SCE&G will be in a secure position if carbon taxes, cap-and-trade systems, or other regulatory mechanisms impose costs on carbon emissions.
Adding equivalent solar and wind generation was not an option. To produce as much electricity as the VCSNS, a solar-powered plant would require panels covering an area the size of Columbia, S.C. Wind generation would require hundreds of turbines stretching across the entire South Carolina coast, the only place in the state with enough wind to power them. By comparison, VCSNS takes up only a few square miles and is not dependent on the weather.
Financing strategies will minimize rate increases to SCE&G’s customers. Legislation passed in 2007 allows SCE&G to recover some costs during construction rather than in one lump sum at the end of the project, dramatically reducing overall costs of the new units by about $1 billion. Estimates indicate this reduction will save SCE&G’s customers approximately $4 billion in electric rates over the life of the new units. This is a far less expensive way of financing a project compared to a large rate increase at the end of the construction cycle.
Unit 1 Gets New Neighbors
Within the boundaries of the 3,600-acre site, the two new units will be located in a laydown area used during the construction of the operating VCSNS Unit 1, a 966-MW three-loop Westinghouse PWR that achieved commercial operation in 1984. That unit is currently supplying 21% of SCE&G’s electricity. In 2004, the NRC extended the plant’s operating license for 20 years, through 2042. Combined, the three units will be capable of generating 3,200 MW.
The existing nuclear unit, auxiliary facilities such as the training center, and transmission line corridors occupy approximately 492 acres of the VCSNS site, and another 784 acres extend into the Monticello Reservoir. The Monticello Reservoir will provide the water requirements for Units 2 and 3. The Monticello Reservoir was formed in 1977 by damming Frees Creek, a small tributary of the Broad River that flowed into Parr Reservoir approximately 1 mile upstream from the Parr Shoals Dam. Most of the remaining VCSNS site area is mixed forest, some of which is managed for timber production. The VCSNS site is located in a sparsely populated, largely rural area, with forests and small farms.
The site is not vulnerable to the natural threats that destroyed the Fukushima nuclear plant. Based on previous and existing environmental assessments, the site—primarily featuring low rolling hills—has no active or capable fault lines in the vicinity of the plant. This was demonstrated during Unit 1 construction and licensing the two new reactors. A tsunami is not going to be a factor because the site is 435 feet above sea level and located more than 100 miles from the ocean.
With the nuclear revival in the Southeast, the region already has a strong technical college system, and two state universities have started nuclear engineering programs. South Carolina State University has an undergraduate nuclear program, while the University of South Carolina has a graduate program. SCE&G and parent company SCANA Corp. are working with Midlands Technical College on a program to train nuclear plant operators.
The construction project continues to recruit and utilize the majority of employees from a skilled craft workforce in South Carolina. More than half of these local workers are from Fairfield, Lexington, Richland, and Newberry counties. Approximately 1,600 Westinghouse/CB&I personnel and contractor and subcontractor personnel are employed on site. As of June 2013, SCE&G had completed hiring slightly over one-half of the operational staffing positions identified as mission critical. The hiring goal for 2013 is to fill approximately 100 such positions. CB&I plans to employ approximately 3,000 to 3,500 employees during the project, a number that is expected to fluctuate during different phases of construction activity.
When they are connected to the grid, the two new units will create about 800 permanent jobs for Fairfield County.
Site Preparation and Recent Progress
Many of the initial activities required to construct a nuclear power plant are not within the NRC’s regulatory authority and are grouped under the term “preconstruction.” These activities started in 2009 and consisted of clearing and grading, excavating, erecting support buildings and transmission lines, and other non-nuclear safety–related activities. These preconstruction activities can occur before, during, and after the COL application is submitted or, in some cases, concurrently with NRC-regulated construction. Although certain preconstruction activities may be outside the NRC’s regulatory authority, many of them can be within the regulatory authority of local, state, or other federal agencies, including certain activities requiring permits.
By 2010, for example, the 13-story module assembly building where structural modules will be assembled prior to actual installation—including administrative and office buildings, training facilities, testing labs, tool shops, and warehouses—had been completed. In addition, more than 6.5 million cubic yards of earth has been excavated in early site preparation for the power block area, the circulating water system, and the switchyard area for Unit 2. Work was also under way on fabricating the reactor pressure vessel and the steam generators, the largest and heaviest components of the AP1000.
Many suppliers are involved in this massive project (Table 1) and the activities outlined below. These status notes are based on the June 2013 quarterly report.
|Table 1. Companies supporting construction and future operation of VCSNS Units 2 and 3. Source: SCE&G|
Plant Design Packages. As of June 30, 2013, the Units 2 and 3 plant design packages issued for construction are 82.4% complete. SCE&G is focusing on nuclear island civil structural design packages, piping design packages, pipe support design packages, electrical cable routing, and conduit design delivery. Monthly oversight meetings have recognized improvements in the pace of producing these packages.
Unit 2 Containment Vessel Bottom Head. On May 22, 2013, the Unit 2 containment vessel bottom head (CVBH) was set in place on its foundation in the nuclear island using the Bigge Heavy Lift Derrick (Figure 1). The CVBH is the steel bowl that forms the base of the containment vessel. With the rigging required for its lifting and placement, the CVBH weighed approximately 990 tons. The CVBH rests on a steel frame and concrete pedestals that had been placed on the Unit 2 nuclear island basemat in April 2013.
|1. A strong foundation. On May 22, 2013, the Unit 2 containment vessel bottom head was set in place on its foundation in the nuclear island. Courtesy: SCANA/SCE&G|
Unit 2 Turbine Building Basement and Condenser B. Placement of the 12-foot-high east, south, and west walls for the Unit 2 turbine building basement has been completed. Backfilling around the Unit 2 turbine building was under way. Work was also nearing completion on the lower section of Condenser B, which is the first of three condensers that will be installed in the Unit 2 turbine building basement. To control vibrations in the turbine building, the condensers will be isolated from remaining structures in the building by a system of GERB springs.
Unit 3 Nuclear Island Basemat. By June the team had completed placement of the upper mudmat for the Unit 3 nuclear island. Form work, rebar installation, and the installation of drain piping and other fittings are under way to support placement of the Unit 3 basemat in 2013.
Containment Vessel (CV) Rings. Fabrication of Unit 2 CV Ring 1 and installation of internal stiffeners is largely complete, with limited welding remaining to the upper equipment hatch. CB&I Services has welded the seams of the first three courses of plates that will form Unit 2 CV Ring 2. The individual welds on the Units 2 and 3 CVBH and CV Rings are subject to radiographic testing for quality. Overall acceptance rates remain above 99%.
Reactor Vessel (RV) and Closure Head. Hydrostatic testing of the Unit 2 reactor vessel and closure head was conducted at the Doosan manufacturing facility in South Korea, and this equipment was delivered to the site this summer (Figure 2). The Unit 2 RV and closure head, together weighing approximately 450 tons, passed through the Port of Charleston and were delivered to the site by train.
Steam Generators. Unit 2 steam generators have completed hydrostatic testing and were being prepared for shipment during the second quarter, when it was decided to send the reactor coolant pump casings to South Korea for installation on the steam generators at the factory prior to shipment. Welding the casings in the controlled environment of the Doosan facilities was determined to be preferable to performing the work on site. Doosan has proven capabilities to perform this work, having completed similar operations for China’s AP1000 project. Machining, cladding, and welding of components of the Unit 3 steam generators continues with no significant issues.
Reactor Coolant Loop Piping (RCL). The Unit 2 RCL surge lines are on site. The Unit 2 RCL cold and hot legs are currently undergoing installation of fittings and instrumentation access points. Work is expected to be completed in the third quarter of 2013. These pipes will then be shipped to the site. Final fabrication work on the Unit 3 RCL cold leg piping and surge lines is under way and is expected to be completed in the fourth quarter of 2013.
Core Make-Up Tanks and Accumulator Tanks. Fabrication and painting of Unit 2 core make-up tanks is occurring along with the successful hydrostatic testing of the Unit 2 accumulator tank. Quality assurance data package reviews are under way in preparation for shipping them to the site in the third quarter of 2013.
Deaerator. During the second quarter of 2013, the Unit 2 deaerator was successfully received on site, off-loaded, and placed in storage. The deaerator is approximately 148 feet long and weighs in excess of 300 tons. It was shipped from South Korea to the Port of Charleston and then barged to a facility on Lake Marion. There it was offloaded and brought to the site by road using a special pusher-puller truck. The deaerator’s length prevented its shipment by rail (Figures 3 and 4). Fabrication of the Unit 3 deaerator is progressing as expected.
Moisture Separator Reheaters. The two Unit 2 moisture separator reheaters have been received on site. The Unit 3 moisture separator reheaters are being fabricated as expected.
Cooling Towers and Cooling Water Pump Stations. As of June 30, 2013, approximately 75% of the precast panels that make up Cooling Tower 2A and 25% of the precast panels that make up Cooling Tower 3A had been set in place. Fans, fan shrouds, electrical equipment, and other equipment were being installed in both cooling towers.
During the second quarter of 2013, installation of foundation pilings for Cooling Tower 2B was completed, and form work and rebar installation to support placing concrete for the foundation and basin of Cooling Tower 2B were under way. The foundations and basins for Cooling Tower 3B were completed, and the unit has been handed over to the cooling tower contractor for the precast panels to be set.
Mudmats for the Unit 2 and 3 cooling water system pump houses were placed. Form work and rebar installation were under way for the placement of the basemat for the Unit 2 pump house.
Turbine Generator. The main generator stator, high-pressure turbine casings and rotors, and low-pressure turbine casings and rotors for the Unit 2 turbine generator were delivered to the site during the second quarter of 2013. Fabrication of the Unit 3 turbine generator components is ongoing.
Safety. The project continues to maintain an excellent safety record that exceeds industry expectations for projects of comparable size. The construction workforce has previously attained more than 3 million manhours worked without a lost-time injury and is currently approaching 2 million manhours without a lost-time injury.
Training and Plant Reference Simulator. The implementation schedule for the Plant Reference Simulator (PRS) continues to support the schedule for training and licensing the AP1000 reactor operators that are required for the initial fuel load for Unit 2 to take place. The four teams created to oversee validation and testing of the PRS began their work during the second quarter of 2013. In June 2013, a combined Westinghouse Electric Co., SCE&G, and Southern Nuclear Co. team conducted a readiness assessment to evaluate the performance of each team and to gauge success. The results of the assessment will be available in the third quarter of 2013.
Initial Licensed Operator Training. Twenty-four students continue in the Initial Licensed Operator (ILO) class that began in 2012. The duration of this class is approximately two years and will culminate with an NRC written exam in August 2014 and a simulator demonstrative exam in December 2014. During the review period, the NRC reported that all 24 students passed the Generic Fundamentals Examination, which is the first step in NRC licensing. Those students are now preparing for site-specific systems exams. A second class of 24 students began the ILO training in June 2013. A third class of 18 students is anticipated to begin in December 2013.
Non-Licensed Operator Training. Eighteen students are enrolled in the Non-Licensed Operator (NLO) program and will complete the program in July 2013. A second NLO class was to begin in August 2013.
Construction Reactor Oversight Process (cROP). While the Operating Reactor Oversight program focuses on the performance of existing nuclear plants, regulatory oversight for new reactors focuses on the construction period between licensing and initial operation. The cROP (as described in IMC 2506, Construction Reactor Oversight Process General Guidance and Basis Document) is implemented when an applicant announces its intent to continue construction on a previously suspended project or submits an application for an early site permit, a limited work authorization, a construction permit, and/or a COL. The cROP remains in effect until regulatory oversight for the plant is transitioned to the Reactor Oversight Process.
For example, the NRC conducted an inspection of SCE&G’s quality assurance program and reported no more than minor findings. The NRC also made routine quality assurance implementation inspections at the site. Certain matters were captured in the Corrective Action Program for the site, but no violations were required to be documented in any reports.
Poised for the Future
SCE&G (55% ownership) and Santee Cooper (45%) will jointly own the facility and share in the costs, output, and eventual decommissioning of the facility. SCE&G will retain sole responsibility for operation of VCSNS Units 2 and 3 after completing all licensing requirements. ■
—James Hylko is a POWER contributing editor.