TVA’s Watts Bar Unit 2 is on track to be the first new nuclear generation in the United States in the 21st Century.

The work to complete the unit is building on proven technology, using established engineering and design standards, and taking advantage of the extensive operating and construction experience available in TVA and the nuclear industry.

TVA’s work will provide a two-unit nuclear power plant with• consistent licensing and design bases for both units;• construction and operational similarities between the units with minimal, known differences that

are addressed through comprehensive training; and• a second unit that is made like new through a comprehensive refurbishment effort that rebuilds or

replaces systems, structures, and components using modern materials and current technology.

The skilled workers performing the work rigorously adhere to – and deliver – high standards of safety and quality. And systems are being completed, tested, and made operationally ready according to a logical schedule that supports key milestones that must be achieved to be ready to load fuel in the reactor and eventually reach commercial operation.

Ultimately, the safe and quality completion of Watts Bar Unit 2 – and its successful transition into TVA’s operating nuclear fleet – will provide an additional 1,150 megawatts of safe, clean, and reliable energy to fuel jobs, businesses, and homes across the region.

Made Like New 1W A T T S B A R U N I T 2

SAFE

PROGRESS

CLEAN

2 W A T T S B A R U N I T 2

ContainmentSystems, structures, and components associated with nuclear safety and reactor cooling have been rebuilt, refurbished, or replaced.

Rebuilt reactor coolant pump motors

New reactor coolant pumps

3W A T T S B A R U N I T 2

New wiring on pressurizer heater

New safety injection system vent valves will reduce radiation dose to employees performing routine jobs while the unit is online.

4 W A T T S B A R U N I T 2

Auxiliary Building

Refurbished and rebuilt residual heat removal system pumps

Replaced residual heat removal system heat exchanger

Systems, structures, and components associated with nuclear safety and reactor cooling have been rebuilt, refurbished, or replaced.

5W A T T S U N I T B A R 2

Refurbished safety injection system pumps

New primary water pumps and motors Replaced switches on chemistry sample valve junction box

Digital Upgrades6 W A T T S B A R U N I T 2

Many instruments and controls that monitor operation of key components of the secondary plant have been replaced and upgraded with digital controls for greater reliability and enhanced monitoring capability.

New digital, dual channel voltage regulator for main

generator and exciter

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New digital supervisory instrumentation for main turbine New local instrument control panel for generator stator cooling hydrogen

Control Building Panels, Boards, and Auxiliary Controls

Relay panel for common station service transformer 6.9 kV shutdown boards for supplying electrical power to safety-related equipment

8 W A T T S B A R U N I T 2

Electrical systems connecting the main control room and the plant equipment have been upgraded and refurbished with digital components and new cabinets.

Auxiliary control room remote shutdown panel controls have been replaced or reconditioned.

Relay panel for the 500 kV switchyard – supporting reliable generation and grid reliability

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Local Controls in the Turbine Building

Panel for component controls in the Turbine Building heater drains and vents system

New hydrogen gas dryer in the generator cooling system

10 W A T T S B A R U N I T 2

Controls for non-nuclear equipment have been upgraded and refurbished to better ensure reliable power generation.

Instrument control panel for components in the raw cooling water system

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Local Controls in the Turbine Building

Turbine Building motor operated valve motor control center

The condenser circulating water motor control center (MCC) breakers were replaced. The MCC controls the system’s refurbished motors and pumps. Unit identification was maintained by painting common controls white and Unit 2 controls blue.

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Main Control Room14 W A T T S B A R U N I T 2

Unit 2 main control room recorders and indicators were replaced and switches reconditioned while minimizing differences between the units. New, digital instrumentation and reorganized control panels provide operators more information and improved ease of operation.

New control panels for steam generator indicator/recorder and upgraded digital instrumentation for common qualified post accident sampling (Common Q) for monitoring reactor water level

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Digital control system display New Westinghouse in-core information surveillance and engineering (WINCISE) system

Unit 2 main control room upgrades required more than 15 miles of electrical wiring.

Secondary Systems Supporting Steam Supply and Power Conversion

The condenser circulating water system uses four large refurbished pumps driven by these refurbished electric motors to circulate water from the cooling towers to the condensers and back. Each pump is capable of circulating 100,000 gallons of water per minute.

Replaced original moisture separator reheater high pressure by-pass valves with more reliable, larger valves

17W A T T S B A R U N I T 2

Pumps, motors, controls, and other components of non-nuclear systems in the Turbine Building that work together to safely and reliably generate electricity have been made like new with the same diligence that has been given to nuclear cooling and safety-related systems.

18 W A T T S B A R U N I T 2

Secondary Systems Supporting Steam Supply and Power Conversion

The standby main feedwater pump in the feedwater system was refurbished offsite by vendor and reinstalled.

New, corrosion-resistant feedwater piping

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New stator coolant heat exchangers in the generator cooling system

Level control isolation valve refurbished – removed original packing containing asbestos, disassembled, refurbished, reassembled, and tested

20 W A T T S B A R U N I T 2

Moisture Separator/ReheatersMoisture separator/reheaters (MSRs) ensure the humidity and temperature of the steam going into the turbine meet design criteria. The Unit 2 MSRs are an upgraded design to support the new main turbine. The original Unit 2 MSRs have been removed, refurbished, and used on Unit 1.

Installation of a new moisture separator/reheater

21W A T T S B A R U N I T 2

Enhanced covers over outdoor control valves help minimize heat-related failures.

Main Turbine and Generator22 W A T T S B A R U N I T 2

The Unit 2 turbine has been upgraded to improve efficiency and power output. The newer design offers increased margin in operating parameters for Watts Bar operators.

Reconditioned main generator

23W A T T S B A R U N I T 2

New low pressure turbine rotors

The electric hydraulic control fluid tank in the turbine/generator control system was refurbished by the vendor.Main turbine oil tank – cleaned and coated inside and out

Transformer Yard Upgrades and Painting

24 W A T T S B A R U N I T 2

Bus ducts and bus duct cooling

cabinets

Painted bus ducts from the Turbine Building

Inspected, upgraded, and refurbished the two station service transformers, three main bank transformers, and associated electrical buses and ducts

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Station service transformer instrumentation was refurbished.

Painting a main transformerStation service transformer 2A

Fukushima Response Modifications26 W A T T S B A R U N I T 2

The FLEX concept for Fukushima modifications provides additional response capability – such as portable generators, water pumps, hoses, and batteries – to add layers of defense against unlikely events that are considered outside the scope of what a plant should be designed or regulated to withstand.

The new FLEX Equipment Storage Building is built to withstand tornadoes, floods, and earthquakes. It contains portable pumps, generators, valves, pipes, and other emergency response equipment.

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Portable water pumps ensure flexible options for cooling

28 W A T T S B A R U N I T 2

One of four new diesel-powered auxiliary generators

Specially built tornado and seismically protected enclosures on top of the Auxiliary Building house auxiliary generators.

Fukushima ModificationsFukushima modifications include FLEX equipment such as additional pumps, generators, batteries, and other equipment located in diverse locations throughout the plant site.

29W A T T S B A R U N I T 2

Lifting an auxiliary generator

A new, seismically protected 500,000 gallon auxiliary feedwater supply tank provides additional water for the auxiliary feedwater system.

Breaker/switch panel connects auxiliary generators to battery chargers.

30 W A T T S B A R U N I T 2

Nitrogen bottle storage station

Example of a new tap

Fukushima ModificationsNew pipes, valves, and instruments have been installed that connect FLEX equipment to existing systems to provide additional cooling water, electrical power, information, and controls.

31W A T T S B A R U N I T 2

Auxiliary feedwater supply tank feeds to auxiliary feedwater supply

Essential raw cooling water system

New instrumentation monitors spent fuel pool water level and temperature.

33W A T T S B A R 2

• Ensure the public’s health and safety

• Protect the safe operation of Watts Bar Unit 1

• Maintain a consistent, predictable, and transparent process for completing and licensing Watts Bar Unit 2

• Establish design basis fidelity with Watts Bar Unit 1

• Make systems, structures, and components like new

Watts Bar Unit 2 Guiding Principles

SAFE CLEAN PROGRESS

www.tva.com/wattsbar2

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