ATTACHMENT A – SMR DESIGN GOALS
Funding Opportunity Number: DE-FOA-0000371
CONSIDERATIONS IN SMR DESIGNS
SMRs hold significant promise for achieving the Administration’s priorities of reducing
greenhouse gas emissions, energy security, gaining independence from foreign energy sources, and
fostering domestic economic prosperity. These reactors also offer additional safety and security
features that improve their resistance to natural phenomena hazards, terrorism and other threats. In
order for SMRs to fulfill this promise, a number of high level goals should be achieved by the
designs. These goals can be categorized as design considerations in the following four general
areas for ease of discussion:
1.
2.
3.
4.
Safety/Licensing
Economics and Financing
Technologies
Proliferation Risk Reduction and Physical Protection
The goals associated with each of these four general areas were developed to meet expressed user
needs through the eventual deployment of the selected SMR designs. Therefore, proposed SMR
designs should consider these general areas as discussed below. A portion of the merit score will
be derived from the ability of the proposed SMR designs to favorably address these four goal areas.
Note that the initial text in each section describing the high-level goals is provided as context, not
as specific SMR design goals that must be addressed.
1. SAFETY/LICENSING
Public acceptance of nuclear energy is closely tied to the perceived safety of the nuclear plant
design and the cumulative operating experience of current nuclear plants. The worldwide
consensus on general nuclear safety objectives is to protect individuals, society, and the
environment from harm by establishing and maintaining effective defenses against radiological
hazards in all nuclear installations. These stated safety objectives are represented by goals related
to plant safety, personnel safety, and public safety. In addition, public acceptance is improved
when the reactor vendor is dedicated to working with the regulator and demonstrating an
appropriate corporate safety culture.
A. Plant Safety
Plant safety is generally evaluated by a combination of deterministic and probabilistic
approaches. Fundamentally, the safety of a given plant design is evaluated by its ability to
control reactivity, remove heat from the core, confine radioactivity, and shield radiation
following a broad spectrum of accident initiators, such as seismic or severe weather events.
SMR proposals should be optimized with regard to plant safety through the use of designs that
employ a defense-in-depth strategy, incorporate diverse systems where necessary, utilize
passive safety features, maximize simplicity, and possibly eliminate or reduce the likelihood of
certain severe accidents through the plant design.
B. Personnel Safety
Personnel safety is enhanced in reactor design primarily through engineered features such as
layout and shielding, and through the execution of a robust set of safety policies, programs and
procedures. These include a robust monitoring program and policies to support the goal of
maintaining occupational exposure as low as reasonably achievable. SMR designs should
comply with NRC regulations regarding occupational radiation exposure such that radiation
exposures are kept below prescribed limits and are further held as low as reasonably achievable.
C. Public Safety
Public safety is a shared responsibility between the plant operator and the national regulator.
An expected advantage of the proposed SMR designs is that they will have a smaller footprint,
lower power levels that yield a smaller source term, and smaller evacuation zones. This will
simplify emergency planning and reduce cost. For SMR designs that are expected to be
deployed in isolated population centers with limited infrastructure, proposals with an
emergency planning zone close to or at the site boundary would be favored. SMR designs
should be as inherently safe as possible and must comply with all U.S. regulations regarding
public exposure.
D. Regulation
The NRC has the responsibility for ensuring the health and safety of the general public, nuclear
workers, and the environment. Early and frequent interaction with the regulator to resolve
design and policy issues inherent to the SMR design is indicative of a proactive corporate safety
culture. SMR vendors should demonstrate a willingness to work with the NRC to address
potential safety concerns and to accelerate the completion of the design certification review.
2. ECONOMICS AND FINANCING
Increased domestic and world energy demand will likely be met with the most cost-effective energy
alternative available regardless of the environmental implications. It is likely that nuclear energy
will be the choice for sustainable energy generation if it maintains a life-cycle cost advantage over
the cost of energy derived from alternative energy sources (fossil fuel, solar, wind, etc.).
Competitive nuclear life-cycle costs will subsequently support pollution and climate change
considerations. Nuclear life-cycle costs include the initial capital requirements, the construction
duration with associated interest costs, and the production costs.
A. Capital Requirements
Nuclear power plants typically have a higher initial construction cost than fossil fuel-based
alternatives. Capital cost may ultimately be the biggest barrier to the deployment of additional
domestic nuclear energy capacity. The commitment to construct any reactor design may
involve a significant portion of a utility’s overall net worth. The investment required includes
the cost to adapt a design to a given site, construct the plant (including the cost of interest
during construction), test, and commission the plant. An anticipated advantage of a SMR plant
is that with a staggered build strategy, two or more reactors can be built in series, spreading the
capital cost over time, providing an earlier supply of energy, and providing for quicker return
on investment. Overall capital cost (expressed as an overnight construction cost) and the peak
capital cost per year as elements of the plant life cycle cost should be minimized in the SMR
design.
B. Construction Duration
Construction duration is closely linked with the capital requirements. Capital costs including
uncertainty in the total project cost, the cost of project delays, and any operational shortfalls
that may be associated with the initial deployment of a given design, adds to the financial risk
of the project. Also, long lead times for the acquisition of key nuclear plant components and the
potential for longer nuclear plant construction times and delays make nuclear power plant
construction riskier than fossil fuel based alternatives. As a result, the expected plant
engineering, procurement, and construction (EPC) duration is a key factor in a customer
choosing nuclear energy to meet growing regional energy needs. Current and projected power
needs may not provide the luxury of a long EPC period compared with alternative energy
sources. Interest during construction charges increase over the construction duration and no
return on the investment (revenue earned, industrialization, economic development, etc.) can
begin until the energy is available for sale to the public and private sectors. An expected
advantage of SMR designs is that they can be built in less time than a larger design and with
less investment risk. SMR designs should seek to minimize construction duration through the
demonstration of smaller plant footprints, the use of fewer components, a higher fraction of
modular factory fabrication and assembly, the implementation of process control, and
improvements in on-site construction techniques.
C. Production Costs
The big advantage of nuclear power is that production costs are traditionally lower than
alternative energy choices. The payback for the large upfront capital requirements associated
with nuclear energy is the production costs. Therefore, solid designs that support longer plant
lifetimes and low production costs, paired with rising prices associated with fossil fuel
alternatives, combine to make nuclear power a favorable energy option. SMR designs should
be optimized with regard to operations and maintenance costs, security costs, fuel and fuel
management costs, and decommissioning costs in order to maintain a competitive life-cycle
cost. It is also important that SMR designs incorporate innovative features and system
simplification in order to offset the economy-of-scale penalty for smaller plant sizes.
D. Resource Utilization
All power plants based on a steam cycle make prolonged demands on mineral and water
resources. Resource utilization should consider longer time scales for the use of SMR assets
and a decrease in the impact on the ecosystem per unit of energy production. SMR plants
should maximize resource utilization through the design with regards to fuel consumption and
heat rejection per unit of electrical or thermal energy produced.
3. TECHNOLOGIES
There are a large number of SMR reactor concepts and technologies that have been proposed that
are currently in various states of development. Goals related to technology include use of proven
technology or assurance that novel technologies are viable, standardization, flexibility of use, ease
of capacity growth, ease of construction, ease of operation and maintenance, expected conversion
efficiency, and plant life.
A. Proven Technology or Assurance that Novel Technologies are Viable
Utilities choosing nuclear energy for the first time desire a lower risk investment based on
reactor designs that employ viable technologies. Chosen technologies should be based on
engineering practices that are proven by testing and operational experience.
B. Standardization
Closely aligned with proven technology is plant standardization. Plant standardization is a goal
of the NRC 10 Code of Federal Regulations (CFR) Part 52 design certification process.
Standardized plant designs will minimize the magnitude of site-specific changes required to
incorporate a certified design, allow components and spare parts to be shared between plants,
help assure the availability of fuel and critical parts, lead to improved construction schedules,
and allow users groups to share data. Proposed vendors and parts suppliers are available to
assure plant longevity and to support the plant over its useful life.
C. Flexibility of Use
The primary objective of the proposed SMR plants should be to supply electricity to the
national grid. However, it may be advantageous to also use nuclear energy in other applications
such as desalinization or other co-generation applications. It is conceivable that the same
nuclear plant may be directed to different applications over time (daily, monthly, seasonally,
etc.). It is also possible that the utility customer may not want to operate the SMR unit full-time
as a base load generator. Therefore, the SMR plant proposals should identify any additional
capability that the designs have to operate efficiently at variable power levels and provide for
applications beyond electricity production.
D. Ease of Capacity Growth
Energy demand growth will eventually lead to the need to consider the expansion of available
nuclear energy. Efficiencies in cost and security can be realized by expanding at an existing
reactor site. A step-wise investment in nuclear energy may also be a more affordable option.
SMR plant designs should have a small footprint and lend themselves to the establishment of a
multi-unit or multi-module site.
E. Ease of Construction
Efficiencies in cost can be realized based on the ease of reactor construction. Advanced
manufacturing techniques and improved logistics can radically affect the construction duration
and cost. Applying quality assurance to the manufacturing process as opposed to the product
can also have a significant effect on the construction duration and cost. SMR plant designs
should aim to streamline and simplify the construction process.
F. Ease of Operation and Maintenance
Reactor plants that are cumbersome to operate and difficult to maintain may not be competitive
with alternate energy sources. Integrated plant designs, providing an effective human-machine
interface, will reduce operational cost, reduce occupational exposures, and facilitate repair and
replacement of equipment. These factors will improve overall plant availability/reliability. The
use of simulators and a robust training program will also enhance operation and maintenance of
the plant. Technologies such as on-line monitoring and maintenance will simplify plant
operations, reduce work force requirements, and shorten outage durations. The number of
active and passive safety components will impact the operation, testing, and maintenance
requirements of the plant. SMR plants should integrate operations, testing, and maintenance
requirements into the design to maximize efficiencies.
G. Plant Life
The high cost of the initial plant construction demands that SMR plants be designed for as long
a lifetime as is technically and economically feasible, because longer lived plants are more cost
competitive with alternative energy sources. Plant aging programs should also be part of the
design process. SMR plants should be designed for an estimated plant life that is consistent
with or can exceed current Generation III+ designs.
H. Electrical Grid
Current reactor plants rely on offsite power as part of the defense-in-depth safety scheme.
Therefore, the stability of the grid, given a trip or shutdown of the reactor, potentially impacts
one layer in the overall safety scheme for a reactor design. Additionally, extreme fluctuations
in the grid could cause a turbine trip in an operating reactor plant. SMR plants should be
designed to be resilient to grid fluctuations and have sufficient safety resources given a loss of
offsite power.
4. PROLIFERATION RISK REDUCTION AND PHYSICAL PROTECTION
SMR designs need to be sensitive to concerns regarding the theft or diversion of fissile material,
particularly since there may be a burgeoning international market for these designs once they are
certified by the NRC. The design of SMRs should be such that the potential for the diversion of
weapon-usable nuclear material or undeclared production of weapon-usable material is eliminated.
Further, the SMR designs should be such that the potential for the theft of fissile material is
minimized. Appropriate controls should be incorporated in the design of SMR plants to ensure the
deterrence of proliferation or nuclear terrorism wherever the nuclear reactors are deployed.
A. Spent Fuel and Waste Management
All nuclear power plants generate long-lived radioactive materials. SMR proposals should
optimize the plant design to manage nuclear waste, including collection, conditioning, storage,
shipping, and disposal. Spent fuel and high-level wastes are certainly a priority; however, all
waste streams should be evaluated, such as activated materials. SMR designs should minimize
the environmental impact of waste associated with plant operation and spent fuel management.
B. Prevention of Diversion, Theft, and Covert Misuse
The attractiveness of nuclear materials used in a reactor design should be as low as reasonably
achievable to deter seizure and overt misuse. A reactor plant should incorporate technical
features and provisions to impede and detect the diversion, theft or covert misuse of all nuclear
materials. SMR plants should be designed in accordance with national and international
guidelines on non-proliferation.
C. Prevention of Sabotage and Physical Protection
A reactor plant should incorporate technical features and provisions to protect against sabotage
and acts of terrorism through the integration of plant siting, facility, arrangements, and system
configuration with the plant security design. SMR plants should be designed in accordance
with national and international guidelines addressing sabotage events.