NuScale-Safety

Report
NuScale’s Passive Safety
Approach
Update September 2011
Contact Information:
Bruce Landrey
Chief Marketing Officer
[email protected]
Dr. Jose N. Reyes, Jr.
Chief Technology Officer
[email protected]
1000 NE Circle Blvd, Suite 10310, Corvallis, OR 97330
(541) 207-3931 http://www.nuscalepower.com
© NuScale Power, Inc. 2011
Passively Safe Reactor Modules
45 MWe Reactor Module
Natural Convection for Cooling
• Inherently safe natural circulation of water
over the fuel driven by gravity
• No pumps, no need for emergency
generators
Seismically Robust
• System is submerged in a pool of water
below ground in an earthquake resistant
building
• Reactor pool attenuates ground motion
and dissipates energy
Simple and Small
• Reactor is 1/20th the size of large reactors
• Integrated reactor design, no large-break
loss-of-coolant accidents
Defense-in-Depth
• Multiple additional barriers to protect
against the release of radiation to the
environment
2
High-strength stainless
steel containment 10
times pressure capability
of a typical PWR
Water volume to thermal
power ratio is 4 times
larger resulting in better
cooling
Reactor core has only
5% of the fuel of a large
reactor
Large Pool of Water Holds Reactor Modules
12-module, 540 MWe NuScale Plant
NuScale nuclear power
reactors are housed inside
high strength steel
containment vessels and
submerged in 4 million
gallons of water below
ground level inside the
Reactor Building.
The Reactor Building is
designed to withstand
earthquakes, floods,
tornados, hurricane force
winds, and aircraft
impacts.
3
Reactor and containment are
submerged in underground
steel-lined concrete pool with
30-day supply of cooling water.
Any hydrogen released is trapped in
containment vessel with little to no
oxygen available to create a
combustible mixture.
Added Barriers Between Fuel and Environment
Conventional Designs
1.
Fuel Pellet and Cladding
2.
Reactor Vessel
3.
Containment
7
6
Ground level
NuScale’s Additional Barriers
4.
4
Water in Reactor Pool (4 million
gallons)
5.
Stainless Steel Lined Concrete
Reactor Pool
6.
Biological Shield Covers Each
Reactor
7.
Reactor Building
4
3
5
2
1
Stable Long Term Cooling
Reactor and nuclear fuel cooled indefinitely without pumps or power
WATER COOLING
5
BOILING
AIR COOLING
Spent Fuel Pool Safety
Increased Cooling Capacity
•
•
•
More water volume for cooling per fuel assembly than
current designs
Pool can accommodate high density fuel racks that meet
NRC and EPRI requirements or low density racks that
meet NRC requirements and also offer the potential for
long term air-cooling.
Redundant, cross-connected reactor and refueling pool
heat exchangers provide full back-up cooling to spent fuel
pool.
External Coolant Supply Connections
•
Auxiliary external water supply connections are easily
accessible to plant personnel and away from potential
high radiation zones (current problem in Japan)
Below Ground, Robust Deep-Earth Structure.
•
•
•
•
7
Below ground spent fuel pool is housed in a seismically
robust reactor building
Stainless steel refueling pool liners are independent
from concrete structure to retain integrity
Pool wall located underground is shielded from tsunami
wave impact and damage
Construction of structure below ground in engineered
soil limits the potential for any leakage
Protection Against Extreme Events
Events and Threats
EARTHQUAKES, FLOODS, TORNADOS,
AIRCRAFT IMPACT
COMPLETE STATION BLACKOUT/ LOSS OF
OFFSITE POWER
NuScale Plant Design Features
• Deeply embedded reactor building provides robust seismic and external hazards
protection.
• Passively Safe Nuclear Fuel and Containment Cooling Systems do not require onsite
power, offsite power or diesel generators for safety.
• No external water required for safety.
• Containments submerged in underground stainless steel-lined concrete pool filled
with 30 day supply of cooling water.
EMERGENCY
CORE COOLING
• Air cooling adequate for indefinite period of decay heat removal beyond 30 days.
CONTAINMENT INTEGRITY
AND ULTIMATE HEAT SINK
• No combustible mixture of hydrogen and oxygen inside containment.
• Unlimited performance window: No need for external intervention.
• Housed in underground protected structure.
SPENT FUEL POOL INTEGRITY
8
AND
COOLING
• Has approximately 4 times the water volume of conventional spent fuel pools per MW
of thermal power.
Jose N. Reyes, Jr.
Chief Technology Officer
1000 NE Circle Blvd, Suite 10310
Corvallis, OR 97330
541-207-3931
http://www.nuscalepower.com
10

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