04-01-2013, 04:10 PM
Nuclear Reactors: Generation to Generation
[attachment=46527]
The Key Reactor Factors
Nuclear reactor designs are usually categorized by “generation”; that is, Generation
I, II, III, III+, and IV. The key attributes characterizing the development
and deployment of nuclear power reactors illuminate the essential differences
between the various generations of reactors. The present analysis of
existing reactor concepts focuses on six key reactor attributes:
1. Cost-effectiveness. From the customer’s perspective, a nuclear kilowatt-
hour is, aside from its cost, indistinguishable from a renewable
or fossil-fired kilowatt-hour. Nuclear power must therefore be economically
competitive. Accounting for the life-cycle costs actually
paid by the retail electricity customer has proven to be far from trivial
NUCLEAR R EACTORS : GENER 2 ATION TO GENER ATION
and is one of the more controversial elements in the discussion of
competing energy technologies. Fossil-fired power, without carbon
controls, sets the market price today and will likely continue to do so
over the next decade. What policies or initiatives might make nuclear
power more competitive with current fossil fuel prices? How can the
prospects for nuclear power plant financing be improved?
The History of Reactor Generations
Three generations of nuclear power systems, derived from designs originally
developed for naval use beginning in the late 1940s, are operating worldwide
today (Figure 1).
Generation I
Gen I refers to the prototype and power reactors that launched civil nuclear
power. This generation consists of early prototype reactors from the
1950s and 1960s, such as Shippingport (1957–1982) in Pennsylvania,
Dresden-1 (1960–1978) in Illinois, and Calder Hall-1 (1956–2003) in the
United Kingdom.
NEXT STEPS
After enduring the usual reliability growing pains, Gen I and Gen II nuclear
reactors have proven to be economically successful. According to the Nuclear
Energy Institute, U.S. nuclear power plants in 2006 supplied the secondhighest
amount of electricity in the industry’s history while achieving a
record-low average production cost of 1.66 cents/kWh. Because the capital
costs of many Gen I and Gen II reactors have been paid off, average production
costs have been below 2 cents/kWh for the past seven years. Capacity
factors have remained higher than 90 percent. Self-financing (essentially paid
off the balance sheet) is a key factor, leading to not having to pay any capital
charges and resulting in very low costs to operate these plants. Power upgrades
and improvements in operational efficiency over the past decade have
yielded the equivalent of multiple new nuclear plants. Whether this performance
platform can be extrapolated to the Gen III and III+ designs is
uncertain19 because of the significant overnight cost20 investment for the
GEN III/III+ plants.
The Move to Small Modular Reactors
As President Barack Obama pushes to revive the domestic nuclear power industry
amid mounting concerns about fossil-fired electricity generation, a new
type of small reactor is about to enter the market. Several firms are working
on Gen III and Gen III+ designs that are smaller in scale than the current designs
and in several cases also make use of modular construction techniques.
This small modular reactor (SMR) architecture is based on significant learning-
by-doing efficiencies. The vendors are planning to apply for NRC design
certification pursuant to either 10 CFR Part 50 or 10 CFR Part 52. It is
our understanding that because of new policy issues (e.g., revised emergency
planning zone and accident scenarios) updated or new regulatory criteria and
guides may be necessary. One example of SMR architecture is the mPower
125 MW module (Figure 2), an integral, advanced LWR of modular design,
in current development through an alliance of Babcock and Wilcox Nuclear
Energy Inc. (B&W NE) and Bechtel Power Corporation. The reactor is significantly
smaller than most operating PWRs but is scalable and incorporates
already existing LWR technology, a fully passive safety design, industry-standard
PWR fuel, 60-year used fuel storage, and a four-to-five-year refueling cycle.
The small B&W NE reactor is 75 feet tall and 15 feet wide. Unlike steam
generators in traditional nuclear facilities, its steam generator (the cylindrical
structure seen along the center axis of the reactor vessel in Figure 2) is integrated
within the reactor vessel.
[attachment=46527]
The Key Reactor Factors
Nuclear reactor designs are usually categorized by “generation”; that is, Generation
I, II, III, III+, and IV. The key attributes characterizing the development
and deployment of nuclear power reactors illuminate the essential differences
between the various generations of reactors. The present analysis of
existing reactor concepts focuses on six key reactor attributes:
1. Cost-effectiveness. From the customer’s perspective, a nuclear kilowatt-
hour is, aside from its cost, indistinguishable from a renewable
or fossil-fired kilowatt-hour. Nuclear power must therefore be economically
competitive. Accounting for the life-cycle costs actually
paid by the retail electricity customer has proven to be far from trivial
NUCLEAR R EACTORS : GENER 2 ATION TO GENER ATION
and is one of the more controversial elements in the discussion of
competing energy technologies. Fossil-fired power, without carbon
controls, sets the market price today and will likely continue to do so
over the next decade. What policies or initiatives might make nuclear
power more competitive with current fossil fuel prices? How can the
prospects for nuclear power plant financing be improved?
The History of Reactor Generations
Three generations of nuclear power systems, derived from designs originally
developed for naval use beginning in the late 1940s, are operating worldwide
today (Figure 1).
Generation I
Gen I refers to the prototype and power reactors that launched civil nuclear
power. This generation consists of early prototype reactors from the
1950s and 1960s, such as Shippingport (1957–1982) in Pennsylvania,
Dresden-1 (1960–1978) in Illinois, and Calder Hall-1 (1956–2003) in the
United Kingdom.
NEXT STEPS
After enduring the usual reliability growing pains, Gen I and Gen II nuclear
reactors have proven to be economically successful. According to the Nuclear
Energy Institute, U.S. nuclear power plants in 2006 supplied the secondhighest
amount of electricity in the industry’s history while achieving a
record-low average production cost of 1.66 cents/kWh. Because the capital
costs of many Gen I and Gen II reactors have been paid off, average production
costs have been below 2 cents/kWh for the past seven years. Capacity
factors have remained higher than 90 percent. Self-financing (essentially paid
off the balance sheet) is a key factor, leading to not having to pay any capital
charges and resulting in very low costs to operate these plants. Power upgrades
and improvements in operational efficiency over the past decade have
yielded the equivalent of multiple new nuclear plants. Whether this performance
platform can be extrapolated to the Gen III and III+ designs is
uncertain19 because of the significant overnight cost20 investment for the
GEN III/III+ plants.
The Move to Small Modular Reactors
As President Barack Obama pushes to revive the domestic nuclear power industry
amid mounting concerns about fossil-fired electricity generation, a new
type of small reactor is about to enter the market. Several firms are working
on Gen III and Gen III+ designs that are smaller in scale than the current designs
and in several cases also make use of modular construction techniques.
This small modular reactor (SMR) architecture is based on significant learning-
by-doing efficiencies. The vendors are planning to apply for NRC design
certification pursuant to either 10 CFR Part 50 or 10 CFR Part 52. It is
our understanding that because of new policy issues (e.g., revised emergency
planning zone and accident scenarios) updated or new regulatory criteria and
guides may be necessary. One example of SMR architecture is the mPower
125 MW module (Figure 2), an integral, advanced LWR of modular design,
in current development through an alliance of Babcock and Wilcox Nuclear
Energy Inc. (B&W NE) and Bechtel Power Corporation. The reactor is significantly
smaller than most operating PWRs but is scalable and incorporates
already existing LWR technology, a fully passive safety design, industry-standard
PWR fuel, 60-year used fuel storage, and a four-to-five-year refueling cycle.
The small B&W NE reactor is 75 feet tall and 15 feet wide. Unlike steam
generators in traditional nuclear facilities, its steam generator (the cylindrical
structure seen along the center axis of the reactor vessel in Figure 2) is integrated
within the reactor vessel.