The document discusses the management of ageing assets at Sellafield using a systems engineering approach. It notes that Sellafield has a large number of ageing assets and is shifting from a reactive to proactive approach through system engineer ownership of plant systems. Key aspects of the new approach include categorizing assets by importance to prioritize condition assessments, using mathematical models to predict asset aging over time, and taking a "condition and system health" approach to maintenance planning. The goal is to consistently manage risk across all assets and identify issues early through rigorous monitoring of critical systems.

2. Management of Ageing Assets at
Sellafield as part of a Systems
Engineering Approach
2

3. The concept of “Ageing”
The effects of environment and
service will in time degrade assets to a
level of physical condition or
performance where actions over and
above routine maintenance are
required to keep the asset fit-for-
service for the remainder of its
intended life. This is the concept of an
‘ageing asset’.
Source HSE RR912 “Management of ageing -
A framework for nuclear chemical facilities” (2012)

4. RR912 Headline Paragraphs
• Managing ageing plant effectively requires a paradigm shift in
the way that asset condition is regarded, assessed and
maintained.
• The conventional approach to asset management is often
reactive.
• The focus is on carrying out work that must be done now,
rather than work that will prevent future problems.
• The result is often unanticipated failures, long backlogs of
maintenance work and no time to carry out the preventative
maintenance which would alleviate many of the problems
4

5. Quick Figures - Sellafield by
numbers
That’s a lot of Assets

6. Sellafield Today
NO MARKING REQUIRED

7. Pre-Systems Engineering
• Preventative Maintenance identified, scheduled and
delivered with a focus on demonstrating maintenance of
nuclear safety functions
• Asset Condition assessment conducted by Asset
Management team with aim to identify and deal with
degraded asset condition
• Technical teams delivering bespoke ageing management for
specific key assets
• High level and broad ranging asset categorisation process
that was suboptimal at focussing priority and rigour of the
above activities
7

8. Systems Engineering Developments
• System Engineer “ownership” of Plant Based Systems
• Periodic (Plant Based) System Health Reporting
• Top down Asset Importance Categorisation process to drive
a consistent and graded approach
• Graded Asset Condition Assessment process driven by asset
importance categorisation
• System Engineers engage in appropriate ageing
management as a requirement of the Asset Condition
Assessment process
• Graded System Health Monitoring set to takeover from
System Health Reporting
8

9. Organisational Strategic Planning Elements
NDA Client Specification, Strategic Objectives, Decision Calendars, New Build, Wiring Diagrams, Scope and Context,
Performance Plan
Socio Economic
Environment
Risk & Review
Safety Case,
Risk
Management,
Asset Risk /
QRP,
Business
Continuity,
Condition /
System
Health,
Compliance &
Audit,
Asset
Management
Group and
Governance
Committee,
etc
Asset Management
Strategy & Planning
Asset Management Policy
& Strategy, Integrated
Waste Strategy including
Decommissioning.
Magnox & Oxide
Operating Plans, etc
Asset Management
Decision Making
Strategic Modelling,
Sellafield Site
Remediation Model,
etc
Organisation
& People
Enablers
Sellafield Ltd
Organisational
Design,
Asset
Management
Roles &
Accountabiliti
es (R2A2s),
Sellafield Ltd
Training Policy
(ISO 9001).
Asset Information
Information Strategy, Information Categorisation,
Information Systems, Information R2A2’s
Domestic /
Overseas
Customers
Regulators / Legal
Requirements
Asset Owner
(Government /
NDA)
Lifecycle Delivery
Asset Care &
Contingency
Plans
Dispose Maintain
Acquire
Operate
AMP
Based on the IAM Conceptual Model for Asset Management
ScopeofSellafieldAssetManagementSystem

10. 10
A System Health
Approach

11. 11
• With the significant number of assets delivering a diverse
range of missions
• Where should you go proactively looking for risk first?
• Are resources aligned to the areas where priority attention is
required?
“To help Sellafield apply appropriate and consistent levels of
rigour to their assets so that risk to programme delivery can
be identified and managed early enough to keep both risk and
cost at tolerable levels.”
Asset Importance
Categorisation – why
do it?

12. General Categorisation Considerations
• Functional Importance Categorisation - Not Risk – The output from
categorisation helps prioritise where and how hard we go looking for risk.
• Categorisation cannot be all things to all people – it should guide further
activities/rigour but never prevent us from doing the right thing.
• Statutory/Regulatory requirements must be carried out regardless of
Importance Categorisation output.
• We are legally required to routinely
• Test fire alarms
• Inspect ladders and lifting equipment etc.
• This process is intended to identify what we are going to do over and beyond
our “business as usual” requirements
• Otherwise everything becomes “important” and the process fails to provide
sufficient discrimination to help us prioritise additional rigour.
12

13. 13
• The Asset Categorisation process is applied by the System
Engineer using the Asset Management Database
• A discrete question set helps to identify how a loss of asset
function impacts on key themes including:
• Nuclear safety
• Productivity
• Emergency response
• Environmental Protection
• The functional importance ranking assesses how
dramatically a loss of function could impact these themes
• A separate resilience score captures if the loss of function
can be delivered by other assets or means (…….or ultimately
whether we have resilience from within)
Application of Importance Categorisation

14. Application of Asset Categorisation
14
• Ideally everything on site would be categorised down to
nuts and bolts
• This would be very time consuming and severely hamper
benefit delivery
• A top down approach was adopted to help focus attention
from the start

15. 15
Plant Based System
Functional
Area
Functional
Area
Functional
Area
Sub-
system
Sub-
system
Sub-
system
Sub-
system
Sub-
system
SSC
SSC
SSC
SSC
SSC
SSC
SSC
StrategicObjectives
SystemEngineerAnalysis
Top-down approach to Asset
Importance Categorisation
LineofSight
Functional Plant
Building
Functional Group

16. Resilience
Importance
Single point
vulnerability
Back up system exists Several levels of
redundancy
High importance • Detailed maintenance
strategy, top priority to carry
out
• Full understanding of ageing
(modelled, expert input)
• Full reporting of performance
• Detailed maintenance
strategy, top priority to carry
out
• Full understanding of ageing
(modelled, expert input)
• Full reporting of performance
• Generic maintenance strategy
exists
• Some understanding of ageing
(modelled)
• Some reporting of
performance
Moderate importance • Detailed maintenance
strategy, top priority to carry
out
• Full understanding of ageing
(modelled, expert input)
• Full reporting of performance
• Generic maintenance strategy
exists
• Some understanding of ageing
(modelled)
• Legal requirements only
Low importance • Generic maintenance strategy
exists
• Legal requirements only • Legal requirements only
16

17. Ageing Management Circle
17
• For the suitably important assets, the System Engineer follows the
Ageing Management Circle1 for their assets
1- C Pickford, M Niblett, How do I Assess Structure System or Component (SSC) Condition and Manage
Ageing?, SLP 1.06.03.04, Issue 3, April 2016, Sellafield Ltd

18. Asset Condition Assessment - comes
with (or without) Confidence
18
rget
nfidence
Degradation
Mechanisms
Identified
Degradation
Mechanisms
Modelled
Degradation
Mechanisms
Monitored
Confidence
Level
Achieved
Justifying Statement
(Confidence Achieved)
Action Plan to
Address Confidence
Gap
Confidence Factors
Confidence
Achieved Confidence
Show Hide
Condition Grade
A Good Condition
B Acceptable
Condition
C Poor
Condition
D Unacceptable
Condition
Required Confidence
Level
Confidence Achieved
Optimal Optimal
High High
Moderate Moderate
Low Low
Minimal Minimal
Optimal Optimal
High High
Moderate Moderate
Low Low
Minimal Minimal
Optimal Optimal
High High
Moderate Moderate
Low Low
Minimal Minimal
Optimal Optimal
High High
Moderate Moderate
Low Low
Minimal Minimal
Optimal Optimal
High High
Moderate Moderate
Low Low
Minimal Minimal
Required Confidence Level is set by
Asset Importance Categorisation
Confidence Gap RYAG relates to the
Confidence Gap and is always
reported alongside Condition Grade
……plus a future looking prediction as to how condition
will change over time

19. 19
• Large number of problems
• Little data
• Requirement to schedule interventions based on facts
• Organisation change – Introducing System Engineering
• Ownership and Responsibility
Mathematical Ageing Models

20. 20
• Ageing models are used wherever a loss of function is
intolerable (Asset Categorisation)
• The term “ageing model” is loosely applied and can mean
several things
• A prediction of when spares will run out/obsolescence kicks in
• A mathematical model predicting wear/corrosion/etc
• The purpose of an age model is to identify when an
investment in the asset is likely to be required
• Change design as spares no longer required
• Replace structural elements
• Stop production
Ageing Models

21. SEs Approach to Age Modelling
• Complete the following table for those systems which are
suitably important
• A database of starter forms exist and continues to grow
simplifying this form development
21

22. SEs Approach to Age Modelling
• This form allows us to begin to understand how to mitigate
ageing
• Remove stressors
• Change environment
• Change how it is operated
• Improve design
• New material
• New geometry
• Improve maintenance strategy
• Input to TBoM
• Crucially it doesn’t tell us how quickly the asset is going to
degrade
22

23. SEs Approach to Age Modelling
• Need to understand rate of ageing as well as mechanism
• Fundamental to this is the operating context
• How component is used
• Where it is operated
• Why are planes stored in the Nevada desert and not on the
beach at site?
• Need to understand how much the component can degrade
by and when it was installed
• Material loss
• Change in properties etc.
• Potential data management issue when assets are 70 years
old!
23

24. SEs Approach to Age Modelling
• Expecting System Engineers with different
backgrounds/disciplines to develop age models is unrealistic
• Expecting a central expertise to develop age models for all
suitably important assets on site is equally unrealistic
• A database has been developed which:
• Captures the knowledge of the central expertise
• Make use of these data simple to apply to models
• Crucially, the most important assets require any models to
be reviewed/verified by the central expertise
24

25. 25
Ageing Models Database

26. 26
Ageing Models Database

27. 27
Age model- Example

28. 28
Age model- Example

29. 29
Adding real data to the model impacts on predicted life and proposed inspection
frequencies:
Prior to data the recommendation was 0.7 /
0.1
Age model- Example

30. Ageing Models Database
• Simple tool, guides user and provides relevant points of
contact for further information
• Uses verified data to make life predictions
• Avoids spurious internet searches!
• Drives inspection frequencies
• Dependent on importance, confidence, importance and remnant
life
• As data are gathered these are refined
• Crucial that, where possible, models are verified by real
measurement data
• Increases confidence
• Refines models for others
30

31. 31
Where are we on this journey?
• Organisation Structure
• Gathering Data
• Providing tools and processes
• Challenge
Summary

32. Thank you for listening
32
Any Questions?