DSHW-2014-002470 - 0901a068803fff1d

State of Utah
GARYR. FIERBERT
Governor
SPENCERJ. COX
LieuEtunl Gweraor
Department of
Environmental Quality
Amanda Smith
Executive Director
DIVISION OF SOLID AND
HAZARDOUSWASTE
Scott T. Andenon
Director
Solid and Hrzrrdous Waste Control Board
Kevin ltlurray, Cluir
Dennis Riding Vice4lwir
Eugene Colc, DrPH
JeffCoombs, MPI1 LEHS
Mark Franc
Brett Mickelson
AmandaSmirh
Shanc Whimey
Dwayne Woollcy
Scoft T. Anderson
Exccative Secretary
February 18,2014
George Gooch, Manager
ATK Environmental Services
ATK Launch Systems - Promontory
P.O. Box 707
Brigharn City, UT 84302-0707
RE: Response to Comments on the Hybrid Air Dispersion Modeling Report
OB/OD Treatment Units, ATK Launch Systems - Promontory Facility
urD009081357
Dear Mr. Gooch:
The Division of Solid and Hazardous Waste has completed its review of ATK's responses to comments
on the hybrid modeling report (dated December 17,2013). ATK's responses address all of our concems
except for the issue regarding the calculation of the initial vapor cloud dimension which is discussed in
Specific Comments #8, #10 aoa +tf . Our evaluation of ATK's responses to these comments is given
below.
Evaluation of the Responses to Specific Comments 8, 10, and L3: Please refer to Section 2.6-3 of
Volume 2 of the OBODM Users Guide. Section 2.6.3 presents Equation2-7tfor calculating the radius
of a continuous sotrce with a large initial horizontal radius, rp. Equation2-7tappears to be a function
of plume rise (which is a function of wind speed and air temperature) and te initial radius (rp) of the
ro*"". Equation 2-75 of Section2.6.3 further indicates the initial radius of the source is not only a
function of heat content and quantity detonated but also air temperature. Thus, it is not clear that a
single value for the initial vapor cloud diameter is appropriate for the air modeling analysis.
As a result of discussions between ATK and the Division on February 4,2014, it was determined that
ATK will revise the discussion in the Draft Hybrid Modeling Repgrt to describe how a single value of
air temperature was specified and used in calculating the initial radius rn. This additional information
will also indicate that, based on a cursory analysis, changes in air temperature do not have a significant
impact on the value of rn.
195 North 1950 West'Salt Lakc City, UT
Mailing Address: P.O. Box l'f4S80 ' Salt Lakc City, UT 84114-4880
Telephonc (801) 536{200'Fax [phone] 'T.D-D. (801) 5364414
wttnlileq.utahgoo
Prinrcd on l00o/o rccyclcd PryerDSHW-2014{@470
(Over)
In addition, the information provided in Volume 2 of the OBODM Users Guide is not clear regarding
whether the results of Equation 2-71 or Equation 2-75 should be used as the basis for determining the
initial sigma y and sigma z values required by AERMOD.
During the February 4,2014 conference call, ATK indicated that rp is the value calculated and reported
by OBODM for the initial radius of an instantaneous (i.e., detonated) source. In addition, it is known
that OBODM is no longer supported by the model developers (or any regulatory agency). Thus, ATK
and the Division determined that the Draft Hybrid Modeling Report should be revised to identiff the
issue (regarding whether the results of Equation2-7I or Equation 2-75 should be used as the basis for
determining inputs to AES.MOD) as a source of uncertainty in the air modeling analysis. The discussion
of this issue will point out that the value of rp is the only lateral dimension reported by OBODM and that
the model itself is no longer supported by its developers or any regulatory agencies.
Please revise the Draft Hybrid Modeling Report as discussed in ATK's responses to our comments and
as discussed above for comments #8, #10 and #13 and submit the revised report by March 10,2014.
If you have any questions, please call JeffVandel at (S0l) 536-0257.
Scott T. Anderson, Director
Division of Solid and Hazardous Waste
STA/Mtjm
c: Blair Palmer; ATK Launch Systems
Paul Hancoch ATK Launch Systems
Cheryl Overstreet EPA Region 8
Lloyd c. Berentzen, MBA, Health offrcer, Bear River Health Deparhnent
Grant Koford, EHS, Environmental Health Director, Bear River Health Deparhnent
DSHW-2o14{02470