Structural Integrity

1. INDIAN STRUCTURAL INTEGRITY SOCIETY
WORKSHOP
Structural Integrity Assessment of Nuclear Energy Assets
9th – 10th May 2018
AERB Auditorium,Niyamak Bhavan-B Mumbai .

2. An Overview of Technology
Development
(Posers & Challenges for Structural
Analysis Community)
SF Vhora,ED(TD),NPCIL
9 May 2018

3. R&D Facilities
R&D activities related to following promote
structural integrity of NPP Structures, Systems
& Components.
• Passive Decay Heat Removal System
• Containment Spray System
• Passive Catalytic Recombiners
• Containment Filtered Vent System
• Pressure Tube burst test studies

4. Remote Tooling
• Remote Tooling activities such as following
promote structural integrity of critical
components and equipment:
• BARCIS Inspection
• Steam generator inspection and debris removal
• Heat exchanger in-service inspection
• Installation, Repair & Refurbishment of reactor
component
• Use of automated welding

5. Indigenization
• Indigenisation promotes structural integrity as
critical raw materials such as steam generator,
pressurizer forgings, end shield tube sheet
plates get manufactured within the country
under regime of strict NPCIL QA coverage.

6. Construction Time Minimization
Certain type of modular construction has
tendency to create conditions which enhance
quality of construction and therefore
structural integrity.
• Preformed Ring Liner, Structural steel floor &
Integral dome modules have proven this
• ESCIA is one prime example of this
• New approach to Speedy fabrication is arrived

7. Posers & Challenges

8. Nuclear Industry Biggest Challenge
• Economic viability of Operating Units & New
Projects in the face of disruptive Renewables
technological & economical advances
• Operating Units – Major Issues
- In service health of critical components
- Plant Life Extension
New Projects :
- Issues coming up during construction which
can significantly delay

9. Regulatory review of Issues during
Project Construction
• Experience world over seems to indicate that the delay
caused by incidents which ultimately impact structural
integrity e.g. Concrete quality, weld quality, Cal vault
• Examples of EPRs at OL3 & FM3 , AP1000 at VC Summer
show huge financial implications & bankruptcies
• Average Construction time of India (9.0y) is about 3-4 years
greater than Korea (5.3y)& China(6.0y)
• For 700 PHWR certain proposed modifications are
worrisome as to further erode economic viability
• Therefore ready analysis capabilities in place with full
models could be a great investment as a time saver
• This Workshop can promote such an approach

10. Operating Units
KAPS-1,2 Pressure Tube issue
• Possibility of Combination of factors has not
been explored
• In-situ Pressure test after defueling – should it
have been considered?
• Why did we not think to pressure test taken
out PTs earlier?

11. Operating Units – World Over
• Wide variation in approach to life extension
• USA NRC appears to have consistent approach
• Most US plants life extended up to 60 y & thinking of
80 y
• CANDUs in Canada – mostly extending channel life has
given a breather – NPCIL needs to learn from this
approach – collaborate on channel issues
• Elsewhere picture is confused
• Armenia – shutdown after earthquake – decision
revoked when power crisis

12. R&D/TD Perspective based Proposal
• Since NPCIL is going to construct 12 units need to anticipate
likely issues which may crop up impacting structural
integrity aspects
• If two full independent models of RB can be made ready for
taking up analysis & providing results within days could
have a huge commercial benefit
• Some physical model of RB & Internals can be thought of &
tested on shake table
• Impact analysis for assumed RB internal structure & ICW
may show there may not be much of concern
• This workshop may consider proposing such an approach
• R&D/TD funds could be made available

13. Engineering Thinking & Trends which impact
safety & economic viability of 700 PHWRs
These pertain to structural integrity issues in general
Potential for erosion:
• RB diameter increase & spacing increase
• Replacement of structural steel floor with concrete
floor
• PDHRS removal
Potential for helping:
- Adoption of PRL, SSF&HA, ESCIA & Dome with rebars
also preinstalled
- Built-in shuttering cum EP in some parts of RB
- longer term – revert to structural steel option ?

14. Some 700 PHWR New Design Concepts As implemented

15. MODULAR CONSTRUCTION

16. Presentation focus on Major Modular Construction
techniques & New approaches to speed up
fabrication of critical path activities.
A Nuclear project has Nuclear Island, Conventional
Island & Balance of Plant.
Critical path goes through Reactor building.
Benchmarking has established that project completion
can happen from FPC to Commercial in about 50 to
60 months.
Adoption of New Technologies & Excellence in Project
Execution can achieve this.
(Implementation of Modular Construction Ideas were
preceded by Structural Analysis by DTD,NPCIL)

17. PRE-FORMED RING LINER (PRL)

18. Preformed Ring Liner (PRL) Concept Adoption
Backing
Truss Crane hook location
Wire Ropes
Spider
Slings
PRL
 Lesser congestion in IC wall resulting in simplified
construction due to elimination of the Out of plane
portion of backing truss from liner.
 Majority of fabrication can be done at ground,
resulting in good quality weld leading to better leak
tightness in liner.
 Availability of tower crane for other works improves.
 More parallelization in construction work can be
realized leading to substantial construction time
minimization.

19. Recent Major Modular Construction Step at KAPP-3&4

20. STRUCTURAL STEEL FLOOR & HEADER
ASSEMBLIES MODULE (SSF&HA)

21. TECHNICAL FEASIBILITY OF
INTEGRATED
ERECTION of HA &
SSFM(Cont)
ERECTION SEQUENCE

22. TECHNICAL FEASIBILITY OF INTEGRATED ERECTION
of HA & SSFM(Cont)
FEM
analysis

23. STRUCTURAL STEEL FLOOR
MODULES

24. END SHIELD CALANDRIA
INTEGRATED ASSEMBLY (ESCIA)

25. ESCIA
• This idea has the potential to radically change the way NPCIL
Builds new project.
• Concept arrived can eliminate 12 to 16 months from 700
Project schedule
• Is symbolic of addressing the only weakness of NPCIL – timely
execution of projects.
• Adopting this would also call for different approach to Supply
Chain & Project Execution.

26. Technical feasibility of ESCIA
• Feasibility established through detailed study of options
Scheme considers following steps
• Makes use of heavy duty crane to bring the assembly direct to FM vault
• Subsequently uses the current method of sliding the assembly in place
• Does not call for stoppage of civil construction on North side
• Calls for minor change in design of End Shield Calandria side flanges to be made
similar to FM side Flanges.
Why Confident? Successful Implementation of Major Modules PRL & SSFA has been
carried out, Dome in planning stage

27. TECHNICAL FEASIBILITY OF END SHIELD & CALANDRIA INTEGRATED ASSEMBLY (ESCIA)
SEQUENCE OF
ERECTION

28. TECHNICAL FEASIBILITY OF END SHIELD & CALANDRIA INTEGRATED ASSEMBLY (ESCIA)
PROVISION FOR
FULL
REHEARSAL

29. These are preliminary conceptualization views subject to further
detailing & refinement .
ESCIA Preliminary Design of Workshop

30. Vision for future construction
of 700 MWe PHWR

31. Summary
Technology Development Activities of NPCIL are:
• Contributing to Safe & Reliable Operation of NPPs.
• Addressing Supply Chain constraints
• Evolving Methodologies for Quick Construction
• These will provide Robust, Economical & therefore
Export worthy PHWR Technologies for the future
sustainability of the planet.

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INDIAN STRUCTURAL INTEGREITY SOCIETY
(InSIS)
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