Bechtel
SAIC, LLC is a joint enterprise of Bechtel National
and Science Applications International Corporation
(SAIC). BSC is the management and operating contractor
for the Yucca Mountain Project of the U.S. Department
of Energy (DoE). Yucca Mountain, located about 100
miles northwest of Las Vegas, Nevada, is the proposed
site for the long-term geologic repository for spent
nuclear fuel and high-level radioactive waste. These
materials, now stored at 131 sites around the USA,
are a result of nuclear power generation and national
defense programs
The Challenge
Yucca Mountain, Nevada
Bechtel SAIC is tasked with performing a comprehensive
lifecycle cost analysis of the Yucca Mountain Project.
A previous analysis employed two spreadsheets, each
of 4 to 6 Megabytes, with only deterministic treatment
of operational risks and uncertainties. One spreadsheet
accumulates the full program costs. The other projects
the Nuclear Waste Fund, established by Congress
to manage payments from the electric utilities and
the defense legacy (for waste from past nuclear
weapons programs), so as to evaluate its adequacy
to cover disposal costs over the next 100 years
or so. The quantity and treatment of the data created
a sizeable effort to verify the data and analysis
in each spreadsheet, resulting in a model that was
slow and unresponsive
Why Analytica?
Bechtel SAIC chose Analytica on the basis of an
independent comparison of 12 competing software
packages, commissioned from Robert Kenley, PhD.
His 16-page study recommended against spreadsheet
add-ins because of the need for computational efficiency
in uncertainty analysis as well as the need for
simplicity and flexibility in managing multidimensional
arrays. The study made Analytica its sole recommendation
based on its array-handling, influence diagrams,
rich function set, database access, ability to handle
time series, and the quality of its documentation:
"Analytica has an exceptional tutorial, a very
good user guide, and developed the user's skill
level to the point where models could be developed
immediately."
Jim Nail, the Project Leader, said "Development
using other tools would have been a lot slower and
provided less capability. The way Analytica handles
multidimensional arrays is a huge advantage over
spreadsheets. The arrays of up to six dimensions
would be virtually unmanageable in a spreadsheet,
especially for quality control. We are so pleased
with Analytica that we're recommending it for several
other major projects at Bechtel SAIC."
The Solution
Bechtel SAIC is now using Analytica to create the
lifecycle analysis model. The Analytica model file
size is now just under 1 Megabyte, about one tenth
of the size of the two spreadsheets it replaces,
even though it has substantially expanded capabilities.
The size decrease results from replacing huge numbers
of repeated cells with simple array formulas, along
with the multidimensional array capabilities. These
make the model much easier to manage and verify.
The Analytica Lifecycle Model provides tremendously
expanded decision analysis capabilities, which would
have been very difficult or impossible in a spreadsheet.
It sets the stage for adding statistical representations
and Monte Carlo analysis of cost risk as risk data
becomes available from a new program risk analysis
effort. All of this has been accomplished while
improved cost estimating methods are producing greater
detail (and quantities of data) for use in the model
analysis.
For more...
Jim Nail,
Bechtel SAIC,
Robert Kenley, Kenley Consulting, Rob Brown, Decision
Strategies, Inc