Abstract
As components engineering has progressively advanced over
the past 20 years to encompass a robust element of
reliability, a paradigm shift has occurred in how complex
systems fail. While failures used to be dominated by
`component failures,' failures are now governed by other
factors such as environmental factors, integration
capability, design quality, system complexity, built in
testability, etc. Of these factors, environmental factors
are difficult to predict and assess. While test regimes
typically encompass environmental factors, significant
design changes to the system to mitigate any failures
found is not likely to occur based on the cost. The early
stages of the engineering design process offer a
significant opportunity to evaluate and mitigate risks
due to environmental factors. Systems that are expected
to operate in a dynamic and changing environment have
significant challenges for assessing environmental
factors. For example, external failure initiating event
probabilities will change with respect to time and new
types of external initiating events can be expect with
respect to time. While some of the well exercised methods
such as Probabilistic Risk Assessment (PRA) [Error!
Reference source not found.] and Failure Modes and
Effects Analysis (FMEA) [Error! Reference source not
found.] can partially address a time-dependent external
initiating event probability, current methods of
analyzing system failure risk during conceptual system
design cannot. As a result, we present our efforts at
developing a Time Based Failure Flow Evaluator (TBFFE).
This method builds upon the Function Based Engineering
Design (FBED) [Error! Reference source not found.] method
of functional modeling and the Function Failure
Identification and Propagation (FFIP) [Error! Reference
source not found.] failure analysis method that is
compatible with FBED. Through the development of TBFFE,
we have found that it can provide significant insights
into a design that is to be used in an environment with
variable probability external initiating events and
unique external initiating events. We present a case
study of the conceptual design of a nuclear power plant's
spent fuel pool undergoing a variety of external
initiating events that vary in probability based upon the
time of year. The case study illustrates the capability
of TBFFE by identifying how seasonally variable
initiating event occurrences can impact the probability
of failure on a month timescale that otherwise would not
be seen on a yearly timescale. Changing the design helps
to reduce the impact that time-varying initiating events
have on the monthly risk of system failure.
Original language | English |
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Title of host publication | 2017 Annual Reliability and Maintainability Symposium, RAMS 2017 |
Publisher | IEEE Institute of Electrical and Electronic Engineers |
ISBN (Electronic) | 978-1-5090-5284-4 |
ISBN (Print) | 978-1-5090-5285-1 |
DOIs | |
Publication status | Published - 29 Mar 2017 |
MoE publication type | A4 Article in a conference publication |
Event | Annual Reliability and Maintainability Symposium, RAMS - Orlando, United States Duration: 23 Jan 2017 → 26 Jan 2017 |
Conference
Conference | Annual Reliability and Maintainability Symposium, RAMS |
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Abbreviated title | RAMS |
Country/Territory | United States |
City | Orlando |
Period | 23/01/17 → 26/01/17 |
Keywords
- risk analysis
- functional modeling
- variable probability
- initiating event