|
| DOE-STD-1024-92
LLNL-5
Slope b.
The slope was selected to be 3.5 after the work of Dr. Robert P. Kennedy.
This parameter exhibits a good stability across studies and across sites.
However, it does vary substantially between ground motion levels, and it does
vary somewhat, but less, between regions.
For example, I took some very rough estimates of the slope b from the mean
hazard curves in the LLNL-EUS study for two hazard levels for 6 sites,
arbitrarily chosen.
around 2 x 10-4
3.8 at 2 x 10-3
Milestone
b = 2.3
Pilgrim
1.9
3.4
Shearron Harris
2.5
4.3
Calvert Cliffs
3.8
5.4
Browns Ferry
1.0
1.8
Susquehanna
3.2
4.0
These numbers show two things:
1.
The slope of b = 3.5 recommended by Dr. Kennedy seems appropriate
within the context of the proposed interim procedure for hazard levels
around 2 x 10-4.
2.
The slope should be increased for higher hazard levels. A slope of
about 4.5 to 5.5 would be appropriate, from the above data (obtained
by multiplying 3.5 by the average of the ratios of b at 2 x 10-3 and 2 x
10-4 above.)
LLNL-6
If the interim document is intended to be distributed to all DOE offices for
actual engineering use, it would be beneficial to clarify some of the technical
language used i.e., geometric mean, ratios, ratios of ratios, etc. A simple
graphical display of the procedure would also facilitate a quick understanding.
LLNL-7
We have reviewed the interim position and find it generally acceptable with
the comments listed below.
The resolution of LLNL versus EPRI hazard curve methodology is very important
since it will affect the guidance for and execution of hazard determination at
DOE sites as required by DOE Order 5480.NPH. The interim guidance does not
resolve the methodology differences but intends to provide a mechanism to use
the results of the LLNL/EPRI studies which were conducted for nuclear power
A-6
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |