CONSTRUCTION EXPERIENCE FROM MODULAR NUCLEAR POWER PLANTS

CONSTRUCTION EXPERIENCE

FROM

MODULAR NUCLEAR POWER PLANTS

Presented by

W.J. (Chris) Zhang

University of Saskatchewan

Saskatoon, Canada

Outline

1. Modularization in NPP

2. Comparison of SMR and AP1000

3. Experience in Construction of AP1000 NPP

4. Conclusions

Modularization in NPP

General modular system:

1. A system is designed into a set of modules which interact through a standard interface.

2. A module can be in itself a modular system, which follows “1”, which reflects the concept of relativity in architectural

definition.

3. A module plays an unique function alone in the system defined at that module level unless otherwise redundancy.

4. The primary expected benefit of modularization: rapid

construction through parallel processing of modules and agile construction through standard interface.

Modularization in NPP

Modularization is not always right to go

1. Fact:

modularization of microelectronics product is very

successful but modularization of large

electrical-mechanical systems is not prevailing.

2. Social constraint.

3. Economic constraint.

4. Technical constraint (NPP).

 Design change deadlock due to technical,

Modularization in NPP

Modularization in NPP:

1. Expectation: Modules are constructed in the local factory, transported to, and assembled on the site.

2. Modular design construction (MDC) in the NPP refers to that expected construction of modular reactors.

3. Kasiwazaki Kariwa-7 (BWR) in Japan, Qinshan-3 in China, Shin-Kori-1 in Korea. After 2000, MDC was widely accepted and used in NPPs (both the large power plants and SMRs).

4. Most of them are under construction (e.g., ABWR in Shimane-3, AP1000 in Sanmen-1/2 and Haiyang 1/2, etc.), some are ready to be built (CAP1400, SMRs, etc.).

Steel liner of dome in Qinshan phase 2 Spray steel module in Qinshan phase 3

CV module

KB26 module (mechanical)

CA01 module

Comparison of SMR and AP1000: overall

 SMR (Nucale): electrical power less than 300 MWe; Large NPP (AP1000): electric power more than 1000 MWe.

 Table 1 shows more details of the comparison of them.

 No difference in general design (technology, safety feature, and architecture), which is the same with other light water SMRs.  SMR: Non-stop refueling.

 SMR: more automation and less human intervention and specialized operation and maintenance.

Items Nuscale AP1000

Principle PWR PWR

Safety features Passive Passive System architecture modularization Modularization

Electrical power 45 MWe X 12 1090 MWe Fuel UO2 (<4.95%) UO2 (0.74~4.235%) Refueling interval 24 months 18~24 months

Fuel assembly 37 157

Design life 60 year

AP1000 NPP overview

 SMR takes the system operation principle of more automation and integration in both physical interface and signal communication among components originally in large NPP.

 Example: in AP1000, RCS consists of one reactor pressure vessel, two steam generators, four reactor coolant pump, one pressurizer and reactor coolant lines, etc. While in Nuscale, all these components are integrated into one module called Nuscale power module.

 Further, in Nuscale, 12 power modules can be added together so that the total power capacity size can vary.

 The major difference between AP1000 and Nuscale is RCS.

Reactor building

Overall dimension of

the containment

module:

AP1000 versus

Nuscale

Items Nuscale AP1000

Construction period (NOAK) 36months 36 months

Construction cost Less than 5000$/Kwe 6000~8000 $/KWe Operation cost 3.0~3.5 ¢/k Wh

Note: The above information may be disturbed by the

fact that in construction of AP1000 in China, many mock

tests and site engineering works for construction are

made, which cause a significant amount of time and

money. With the increasing maturity of AP1000, the cost

and time for construction will be reduced.

Items Nuscale AP1000

Construction period (NOAK) 36months 36 months

Construction cost Less than 5000$/Kwe 6000~8000 $/KWe Operation cost 3.0~3.5 ¢/k Wh

The highly integrated design of RCS, namely NSSS, has

contributed to:



Construction cost reduction,



Construction lead time reduction, and



Less wastes from construction

Modular design construction (MDC) in NPP

modular

design prefabrication assembly transportation lifting installation WBS GT

MDC experience out of AP1000 NPP

Site preparation More interfaces between the two in MDC

Top opening construction technique:

 Nearly all the modules and equipment in AP1000 need to be put into the containment building the top of the building.

 This is completed by the lift crane.

 The large size modules and equipment are first transferred into the CV.

CV Heavy Lift Crane Modul e Modules to be installed

MDC experience out of AP1000 NPP

Availability of the life

crane can be a problem in MDC.

Site layout planning (site-sensitive) technique:

 The best plan is to facilitate the transportation of the wharf, site assembly yard, and the plant, e.g., to make the road straight and short.

 The best plan is also to make the road reusable, less re-work.

NPP Wharf Assembly Yard NPP Wharf Assembly Yard B+C A’

MDC experience out of AP1000 NPP

An integrated planning and scheduling is very useful, which can achieve the best plan, which thus save cost and time.

Flexible yard system technique:

 In AP1000, nearly all the structure modules are assembled on a temporary place which is called yard for the duration of several months to one year.

 Flexible and modularized yard is needed to accommodate different modules. _{IHP (integrated head package)}

module assembly yard

MDC experience out of AP1000 NPP

Yard design should take into account the assembly and non-modular

manufacturing needs, as yard severs as a temporary or buffer shop floor

Counter-deformation techniques for modules:

In AP1000, deformations of modules are serious

problems. Construction has to consider various tools

and jigs to counter deformation during the assembly,

transportation, and lift processes.

Special lift rig for CA01 module _{Special lift rig for CA03 module}

Anti-deformation tool to adjust CA03 module

Assembly interface control technique:



Use of actual dimension instead of design dimension.



Adjustable interfaces of modules are favorable.

Deformation of CA04 module leads to the unfit at interface between CA04 module

and CA04 top flange

Finished product protection technique|:

Modules before being put to the site need to be protected from harsh environments that can be created by the nature such as weather condition and engineering works nearby. Protection of the modules is thus needed in construction of AP1000.

CV

temporary cover

Conclusions

1. Promise of modular NPP (including SMR) is rapid construction and without consideration of pre-manufacturing of modules. 2. Modular NPP (including SMR) can reduce the construction cost

and thus total cost without consideration of the capacity of power generation.

3. Construction of modular NPP has more challenges in

technology, as the NPP is site-sensitive and the large size of the modules does matter, while the notion of modular is against the change due to any external reason.

4. Construction of modular NPP has more challenges in management due to parallel processing of activities.

Conclusions

5. Challenges in both technology and management to construction may compromise the benefits of construction lead time and

cost reduction.

6. Modularization of NPP seems to have missed the consideration of construction.

7. Adjustable modular architecture may be promising to modular NPP.

End and thanks

Conclusions

2.1 Pros and cons of MDC (1) Pros:

• Construction lead time has been shortened depends on the degree of modularization

• Quality of the construction has been improved

• Construction safety was improved

• Construction schedule control is relative feasible

• Work productivity was improved

2 Pros and cons of MDC

2.1 Pros and cons of MDC (2) cons:

• The design shall be completed without changes prior to assembly and installation. Design changes often lead to rework, which would be hard to execute.

• Costs of transportation, temporary assembly yards and heavy lift crane can be a large mount of investment.

• Relationships among the design, vender of materials and site contractor become much closer. Especially for the venders who should closely follow the site schedule than ever before.

• Deformation of modules caused unmatch of interfaces

• Increased depth cross construction (between civil construction and

mechanical/electrical installation) leads to challenge to project management

3 Comparison between SMR and AP1000

3.3 Differences in construction

• RCS is vital important in NPP and also hard to install on site which requires large amount of precise measurement and fit-up work, machining and welding work. It could save a lot of time and manpower during construction. So it is a breakthrough in Nuscale to integrated the RCS into one power module. Because so many

important components in the Nuscale power module, the fabrication might be a difficult.

• Except for the RCS, the other facilities are nearly the same between the two NPPs. The construction methods will be described in following chapter.

3 Comparison between SMR and AP1000

3.4 Difference in environment friendliness

• Global environmental deterioration has been a focus for long time, as is known to all, nuclear is the one non-carbon resource which is classified as clean energy. In the following table, we can see the tons of carbon dioxide equivalent per GWeH is very low of 17.

• Then during the construction of NPP, with the MDC, the numbers of

components and site construction activities were decreased, which