Click here to make tpub.com your Home Page

Page Title: Current Department of Energy Orders and Requirements
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 



DOE-STD-1024-92
Hazards Design and Evaluation Criteria for Department of Energy Facilities"
will, when published, supersede UCRL-15910. For the purpose of this standard
we will continue to use the UCRL-15910 reference with a parenthetical
reference to the future standard. The DOE Natural Phenomena Order and
associated documents establish the following requirements:
The seismic performance goals and the seismic hazard exceedance
probabilities will be based on mean probabilistic estimates; and
Site-specific seismic hazard estimates should be reviewed about every
ten years. If new information and/or methods used to compute
probabilistic seismic hazard changes then revised probabilistic estimates
should be made. In general, the TERA, Inc. seismic hazard curves do
not now represent state-of-the-art seismic hazard estimates.
Unfortunately, UCRL-15910 (DOE-STD-1020) is silent in two critical respects.
First, there is no specific guidance for DOE sites to complete a probabilistic
seismic hazard analysis at set time intervals. As a result the hazard analyses
summarized in UCRL-53582, the TERA, Inc. studies, late 1970's vintage, are
dated. Considerable research and development efforts in the fields of seismo-
tectonics and ground motion estimation since 1980 allow for better modeling of
uncertainties in analysis, more accurate determination of the major contributors
to seismic hazard, and more confidence in absolute numbers. Additionally,
significant amounts of more recent seismic information are available. At some
sites the existing TERA, Inc. results appear to be extremely high at the higher
probabilities (>IOE-3) to such an extent that results are questionable. This
Standard is needed in order to incorporate this more recent information into
seismic hazard determination as soon as possible, and to address the concerns
with the TERA, Inc. study. Unfortunately, the recent studies that have been
completed using the new information are widely divergent in hazard results.
Figure 1 illustrates the issue at hand by showing the median, mean and 85th
percentile probabilistic seismic hazard results for the Savannah River Site for,
both LLNL and EPRI. Figure 1 shows the extreme difference between the two
studies for the mean and 85th percentile and the general consistency between
the median results. This leads to the second issue related to UCRL-15910
(DOE-STD-1020), the issue of uncertainty.
UCRL-15910 (DOE-STD-1020) is silent regarding how uncertainty should be
factored into the probabilistic performance goal and seismic hazard assessment
which directly affects the selection of the peak ground acceleration. While
UCRL-15910 (DOE-STD-1020) specifies that the median response spectral
shape should be used, it does not explicitly define whether the probabilistically
defined peak ground acceleration is associated with a median or mean value,
or some other value. The existing TERA, Inc. curves are labeled "best
estimate" values which are most closely associated with median values using
current approaches. Since the TERA, Inc. values were developed by one team
3


Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business