EMERSONWestinghouse Small Modular Reactor: Taking Proven Technology to the Next Level

Westinghouse Small Modular Reactor: 

Taking Proven Technology to the Next 

Level

Presented to the IAEA INPRO Dialogue Forum

Vienna, October 2011

Dr. Nick Shulyak

Westinghouse Electric Company

Westinghouse SMR - Market Overview

Market Informed Sizing – 225MWe

• Some market observations that contributed:

– Incremental base load additions typically range from 200 to 300 

MWe - based on coal and combined cycle natural gas units

– Greenhouse gas emissions reductions such as coal retirements 

average 150 to 250 MWe - based on actual shutdowns and recent 

public announcements

• Allows Use of Existing Infrastructure of Non-Nuclear 

Stations - Nuclear Option for Non-Nuclear Companies

• Provides Option for Small Underserved Markets

Aging Fossil Plants

District Heating

Remote Markets

Small Grid Markets

Desalinization

Process Heat

SMR Product Specification

Specifications

Thermal Output 800 MWt

Electrical Output >225 MWe

Passive Safety Systems No operator intervention required for 7 days

Core Design 17x17 Robust Fuel Assembly

8.0 ft / 2.4 m Active Length

< 5% Enriched U235

89 Assemblies

Soluble Boron and 37 Internal CRDMs

24 month refueling cycle

Reactor Vessel Size Outer Diameter: 11.5 ft / 3.5 m

Height: 81 ft / 24.7 m

Upper Vessel Package 280 Tons

Containment Vessel 

Size Outer Diameter: 32 ft / 9.7 m

Height: 89 ft / 27.1 m

Fully Modular Construction

Reactor Coolant 

Pumps 8 External, Horizontally-Mounted Pumps

Sealless Configuration

Steam Generator Recirculating, Once-Through, Straight Tube

Pressurizer Integral to Vessel

Instrumentation and 

Control OVATION®-based Digital Control System

What It Is…

• An integral PWR

• Innovative packaging of proven 

components

• The highest levels of safety with 

fewer accident scenarios

• Industry-proven equipment designs

• Compact reactor coolant system and

containment

• An engineered solution for today’s 

clean energy challenges

Pressurizer

Steam 

Generator

Reactor Coolant 

Pumps

Internal Control 

Rod Drives

…Simplicity in Design

SMR Fuel Design: Proven Features, Ease of Licensing3

Westinghouse SMR Reactor Vessel Internals

• Design driven by 

interfaces

– Steam generator

– Coolant pumps

– Reactor vessel

• Utilize AP1000®

component designs – e.g. 

guide tubes, support 

plates and columns, flow 

skirt, vortex suppression, 

etc.

Integral CRDM Design

• Latch assemblies, controls, and interfaces with fuel are all 

based on existing, proven designs

• Three-coil magnetic jack based AP1000® design 

with modifications

– High-temperature

coil winding design

– Sealed, stainless steel 

coil stack housing

– Sealed power conduit 

with leak detection

• Test program initiated

Recirculating Steam Generator

• Straight-tube steam generator 

– Flow from top to bottom of tubes

• Hot leg located in center of tube 

bundle 

– Transfers hot water to the upper 

tube sheet

• Main steam and two feedwater

piping connections

• Recirculating steam generator 

with steam/water mixture 

delivered to steam drum outside 

containment

Steam Generator and Steam Drum System

SMR Reactor Coolant Pumps

• Eight reactor coolant pumps 

providing 12,500 gpm at 100 ft 

of head (no seal injection)

• Each motor ~350 hp

– (460 V, 3 phase)

• Total flow 100,000 gpm

• Driven with 2 variable 

frequency drives (VFD)

• Mount horizontally through 

pressure boundary below 

closure flange

SMR Containment Vessel

• Compact containment

– High pressure

• Size 32-ft diameter and approximately 

89-ft height

• Target is to operate containment at 

vacuum to:

– Increase heat transfer inside containment

– Reduce insulation needs

– Reduce challenge of containment overpressure

• Water cooled on outside of containment

– Annulus flooded

• In vessel retention accomplished by draining 

tanks of water to flood lower reactor vessel