SLAC Radioactive Air (NESHAPs) Program · SOURCE #05 Final Focus Test Beam (FFTB - ended April-06)...
Transcript of SLAC Radioactive Air (NESHAPs) Program · SOURCE #05 Final Focus Test Beam (FFTB - ended April-06)...
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SLAC Radioactive Air (NESHAPs) Program
Henry TranDosimetry Program Manager
Radiation Protection Department (RPD)Environment, Safety and Health (ES&H) Division
Stanford Linear Accelerator Center (SLAC)
DOE Environmental Radiation Protection Program Review (July 23-24, 2007)
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Regulatory Drivers
GeneralProgram
RadioactiveAir
Primary Law
10CFR83510CFR20D
DOEOrder
5400.5450.1
231.1A
5400.5
Limit 100mrem/y
10 mrem/y to MEI
Reference Level
0.1 mrem/y from each release point
Clean Air Act(42USC7401)
Secondary Regulation
40CFR61H(NESHAPs)
State &Local
BAAQMD
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1998 Memo from SLAC to EPA
• Use San Francisco International Airport meteorological data in lieu of SLAC local meteorological data for CAP88
• Only one radioactive air pollutant source pathway: activated air releases
• Confirmatory monitoring scheme: measure radioactivity concentration in the source area and compare to NESHAPs source term calculations.
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REP Radioactive Air Effluent Program
Radiological Environmental Protection (REP) Program Elements
Direct Radiation Radioactive Air Effluents Radioactive Water Programs
Activated Air from Accelerator
NESHAPs report to EPA
8 AMSPeriodic confirmatory
monitoring
Annual NESHAPS report.
Annual ASER
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SLAC NESHAPs Program Documents
• Henry Tran and James Liu, “SLAC National Emission Standards for Hazardous Air Pollutants (NESHAPs) Program Technical Manual”, SLAC Radiation Protection Department, RE-022, June 15, 2007.
• M. Kerimbaev and J. Liu, “Technical Basis Document for SLAC Air Monitoring System”, SLAC Radiation Protection Department, RE-021, May 31, 2007.
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Source Terms: Air Activation
• Beam particles strike certain accelerator components
• High energy photons & neutrons• Strike/interact air molecules • Medium Air
Radionuclide 11C, 13N, 15O
20/10/2min
Beta+(511 keV)
41Ar
Half-life 1.8 h
GammaRadiation
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Other Considered Source Terms
• Activated water products released to the Air: No open surge tanks Not Applicable
• Airborne radioactive particulates in the accelerator housing: no significant detectable contamination Not Applicable
• Machining of radioactive material: in clean room or with HEPA filter Not Applicable
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SLAC Accelerator Facilities
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SLAC Accelerators and Beamlines
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Name FACILITY / DESCRIPTIONX*
[meter]Y*
[meters]
SOURCE #01 Damping Ring (DR) -1969 -28
SOURCE #02 Positron Vault (PV) -31 -21
SOURCE #03 Accelerator Tunnel (LINAC) 780 -49
SOURCE #04 Beam Switchyard (BSY) 1119 -49
SOURCE #05 Final Focus Test Beam (FFTB - ended April-06) 1394 -49
SOURCE #06 Next Linear Collider Test Accelerator (NLCTA) 1388 -95
SOURCE #07 Beam Dump East (BDE) 1452 61
SOURCE #08 Stanford Synchrotron Radiation Lab (SSRL) 1388 61
SOURCE #09 Asymmetric B-Factory, Region 12 (PEP-II-R12) 1477 306
SOURCE #10 Asymmetric B-Factory, Region 10 (PEP-II-R10) 1223 135
SOURCE #11 Asymmetric B-Factory, Region 08 (PEP-II-R08) 1195 -229
SOURCE #12 Asymmetric B-Factory, Region 06 (PEP-II-R06) 1498 -405
SOURCE #13 Asymmetric B-Factory, Region 04 (PEP-II-R04) 1770 -245
SOURCE #14 Asymmetric B-Factory, Region 02 (PEP-II-R02) 1804 128
SOURCE #15 End Station A (ESA) 1376 23
*Distance from the center coordinates located near Sector 20 (see reference maps in Attachment #2)
Release Points
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Souce & MEI Locations (Main Campus)
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Souce & MEI Location (Mid Section)
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Source & MEI Locations (Far West)
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MEI Locations (based on SLAC Aerial Map)
Name MEI DESCRIPTION X* [meter] Y* [meters]
MEI #01 West End @ Whiskey Hill & Sand Hill -2229 -9
MEI #02 North End @ Sand Hill (600 m from Sector 4) -1697 428
MEI #03 Addison Building Area 590 159
MEI #04 North End @ Sand Hill (350 m from Sector 28) 741 336
MEI #05 North End @ Sand Hill (Close to PEP-II-R12) 1440 508
MEI #06 North North East End (between R12 & R02) 1834 410
MEI #07 North East End (close to SLC) 2056 306
MEI #08 East End (Close to SLC) 2244 -160
MEI #09 East End @ Alpine Rd. 2275 -79
MEI #10 East South East End @ Alpine Rd. 2348 -361
MEI #11 South East End @ Alpine Gate 2038 -477
MEI #12 South East End @ Horse Track Offices 1709 -449
MEI #13 North End @ Sand Hill (560 meters from Sector 20) -92 555
MEI #14 East Side of Guest House (non MEI, for place holder) -12230 -12230
MEI #15 North End @ North of Sand Hill Rd (550 m from Sector 28) 772 511
*Distance from the center coordinates located near Sector 20 (see reference maps in Attachment #2)
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SLAC NESHAPs Dose Model
• Use of EPA-approved atmospheric dispersion and dose calculation computer code, CAP88-PC Version 2
• Use SFO 5-year averaged meteorological data (fixed data)
• Use population grid data based on CY2000 census (within 80 km of SLAC)
• Use 0 meter stack height• Use default agricultural data
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NESHAPs Dose Model (Cont.)
• Generate CAP88-PC dose conversion factors for 11C, 13N, 15O, and 41Ar as a function of distances and directions (as Excel lookup table)
• Calculate (Excel) saturation activities of radionuclides (11C, 13N, 15O,and 41Ar) produced for each release point of a facility (Ci/W):– Each facility may have more than one release point– Yield (Ci/W/m) from optimum target based on IAEA Report 188– Reasonable average air path for housing– Volume & surface area of the housing– Monte Carlo calculations (e.g., using FLUKA, MARS or MCNPX)
by simulating actual geometry of beam-target-housing may be performed
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NESHAPs Dose Model (Cont.)
• Calculate (Excel) total radioactivity release per year for each release point:– Reasonable accelerator operational scenarios (length
of operation per year and annual normal beam losses)
– Reasonable air exchange rate for accelerator housing (no forced ventilation at SLAC)
• Calculate (Excel) MEI doses contributed by all source release points
• Determine (Excel) the location for the MEI with highest dose value
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Normalized CAP88 Dose Conversion Factors [mrem/Ci]
LOCATION AR-41 C-11 N-13 O-15
1000-E 1.10E-03 5.50E-04 4.20E-04 1.50E-04
1000-ENE 6.60E-04 2.60E-04 1.70E-04 3.70E-05
1000-ESE 1.40E-03 7.70E-04 6.00E-04 1.90E-04
1000-N 1.20E-03 4.30E-04 2.70E-04 4.80E-05
1000-NE 5.00E-04 1.90E-04 1.20E-04 2.30E-05
1000-NNE 5.10E-04 2.00E-04 1.30E-04 2.50E-05
1000-NNW 5.80E-04 2.20E-04 1.40E-04 2.40E-05
1000-NW 5.30E-04 2.10E-04 1.40E-04 2.80E-05
1000-S 3.00E-04 1.20E-04 8.40E-05 2.10E-05
1000-SE 4.90E-04 2.10E-04 1.50E-04 4.10E-05
1000-SSE 1.60E-04 6.10E-05 3.90E-05 8.40E-06
1000-SSW 1.40E-04 6.80E-05 4.80E-05 1.10E-05
1000-SW 1.70E-04 8.00E-05 5.50E-05 1.10E-05
1000-W 2.10E-04 1.00E-04 6.80E-05 1.40E-05
1000-WNW 3.00E-04 1.40E-04 9.50E-05 2.10E-05
1000-WSW 1.80E-04 8.70E-05 6.10E-05 1.20E-05
100-E 8.10E-02 6.30E-02 5.90E-02 4.30E-02
….. ….. ….. ….. …..
….. ….. ….. ….. …..
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RP Annual Inputs for Facility
Sub Source # FACILITY
AVERAGBEAM
POWER DURING
CY06[kW]
# DAYS OPERATED
DURING CY06
[Days]
FRACPOWER TO SAT
ACTIVITY
FREE AIR
PATH LENGH [meters]
IRR VOLUME [cm^3]
INSIDE SURFACE
AREA [cm^2]
1 North Damping Ring 1.75E-01 244.0 0.10 3.00E+00 7.40E+08 5.67E+06
2 South Damping Ring 5.00E-02 242.0 0.10 3.00E+00 7.40E+08 5.67E+06
3
4
5
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SOURCE #01 Damping Ring (DR) 2.25E-01 244.0
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Saturation Activity Calculations
Sub Source # FACILITY
AVERAGE BEAM
POWER DURING
CY06 [kW]
# DAYS OPERATED
DURING CY06 [Days]
FRAC DAYS
TO MAX [%]
NEUTRON FLUX
DENSITY [n/sec/cm^2]
SAT ACT O-15 [Ci]
SAT ACTN13 [Ci]
SAT ACTC-11 [Ci]
SAT ACT AR-41
[Ci]
1North Damping
Ring 1.75E-01 244 100.00% 3.86E+03 7.88E-05 1.47E-04 1.58E-05 1.17E-05
2South Damping
Ring 5.00E-02 242 99.18% 1.09E+03 2.23E-05 4.17E-05 4.46E-06 3.32E-06
3
4
5
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SOURCE #01Damping Ring
(DR) MAX: 244 1.01E-04 1.89E-04 2.02E-05 1.50E-05
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Facility Activity Releases
FACILITY
# DAYS OPERATED
DURING CY06[Days]
SAT ACTO-15 [Ci]
SAT ACT N13 [Ci]
SAT ACTC-11 [Ci]
SAT ACT
AR-41 [Ci]
SOURCE #01 Damping Ring (DR) 244 1.01E-04 1.89E-04 2.02E-05 1.50E-05
AIR EXCHANGE
PER DAY ASSUMPTIONS Radionuclide
Sat Activity [Ci*/Rel]
Number of
Release per Year
Activity Released
[Ci/yr]
Percent Contribution
[%]
1 No decay (conservative !) O-15 1.01E-04 244 2.47E-02 31.1%
1Sealed Facility (assume 1 air change
leakage/day) N-13 1.89E-04 244 4.60E-02 58.1%
1 C-11 2.02E-05 244 4.93E-03 6.2%
1 Ar-41 1.50E-05 244 3.67E-03 4.6%
TOTAL: 3.25E-04 7.93E-02 100.0%
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Yearly Activity CalculationsSOURCE FACILITY
O-15[Ci/yr]
N-13 [Ci/yr]
C-11 [Ci/yr]
Ar-41 [Ci/yr]
TOTAL [Ci]
Percent Contrib.
[%]
SOURCE #01 Damping Ring (DR) 2.47E-02 4.60E-02 4.93E-03 3.67E-03 7.93E-02 0.05%
SOURCE #02 Positron Vault (PV) 1.12E+01 2.09E+01 2.24E+00 1.35E-01 3.45E+01 20.43%
SOURCE #03 Accelerator Tunnel (LINAC) 2.26E-01 4.22E-01 4.53E-02 6.43E-03 7.00E-01 0.42%
SOURCE #04 Beam Switchyard (BSY) 1.66E+00 3.09E+00 3.31E-01 8.47E-02 5.16E+00 3.06%
SOURCE #05 Final Focus Test Beam (FFTB - ended April-06) 3.56E-01 6.65E-01 7.13E-02 8.77E-03 1.10E+00 0.65%
SOURCE #06 Next Linear Collider Test Accelerator (NLCTA) 2.00E-01 3.73E-01 3.99E-02 7.75E-03 6.20E-01 0.37%
SOURCE #07 Beam Dump East (BDE) 4.75E-01 8.87E-01 9.50E-02 1.03E-01 1.56E+00 0.92%
SOURCE #08 Stanford Synchrotron Radiation Lab (SSRL) 3.17E-03 5.92E-03 6.35E-04 1.00E-04 9.83E-03 0.01%
SOURCE #09 Asymmetric B-Factory, Region 12 (PEP-II-R12) 6.48E-01 1.21E+00 1.30E-01 3.69E-02 2.02E+00 1.20%
SOURCE #10 Asymmetric B-Factory, Region 10 (PEP-II-R10) 2.44E+01 4.55E+01 4.87E+00 1.39E+00 7.61E+01 45.11%
SOURCE #11 Asymmetric B-Factory, Region 08 (PEP-II-R08) 1.09E+01 2.03E+01 2.18E+00 6.20E-01 3.40E+01 20.15%
SOURCE #12 Asymmetric B-Factory, Region 06 (PEP-II-R06) 9.85E-02 1.84E-01 1.97E-02 5.61E-03 3.08E-01 0.18%
SOURCE #13 Asymmetric B-Factory, Region 04 (PEP-II-R04) 3.89E+00 7.26E+00 7.78E-01 2.22E-01 1.21E+01 7.20%
SOURCE #14 Asymmetric B-Factory, Region 02 (PEP-II-R02) 9.85E-02 1.84E-01 1.97E-02 5.61E-03 3.08E-01 0.18%
SOURCE #15 End Station A (ESA) 4.04E-02 7.54E-02 8.08E-03 4.06E-03 1.28E-01 0.08%
SOURCE #16 SABER (Future) 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00%
SOURCE #17 LCLS - Undulator (Future) 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00%
SOURCE #18 LCLS - Dump & FEE (Future) 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00%
SOURCE #19 LCLS - BTH, LINAC, BSY (Future) 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00%
SOURCE #20 SPARE (Future Source) 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00%
TOTAL: 5.42E+01 1.01E+02 1.08E+01 2.63E+00 1.69E+02 100.00%
Percent Contribution [%]: 32.10% 59.92% 6.42% 1.56% 100.00%
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MEI Dose Calculations
WHERE? CONTRIBUTE TO MEI DESCRIPTION TOTAL [mrem]
MEI #01 West End @ Whiskey Hill & Sand Hill 8.06E-04
MEI #02 North End @ Sand Hill (600 m from Sector 4) 1.55E-03
MEI #03 Addison Building Area 4.32E-02
MEI #04 North End @ Sand Hill (350 m from Sector 28) 7.27E-02
MEI #05 North End @ Sand Hill (Close to PEP-II-R12) 1.12E-01
MEI #06 North North East End (between R12 & R02) 5.26E-02
MEI #07 North East End (close to SLC) 3.75E-02
MEI #08 East End (Close to SLC) 7.48E-02
MEI #09 East End @ Alpine Rd. 5.85E-02
MEI #10 East South East End @ Alpine Rd. 5.91E-02
MEI #11 South East End @ Alpine Gate 6.41E-02
MAX MEI #12 South East End @ Horse Track Offices 1.16E-01
MEI #13 North End @ Sand Hill (560 meters from Sector 20) 3.85E-02
MEI #14 East Side of Guest House (non MEI, for reference) 1.94E-03
MEI #15 North End @ North of Sand Hill Rd (550 m from Sector 28) 5.44E-02
MEI #16 SPARE MEI (Future Use) 1.94E-03
MEI #17 SPARE MEI (Future Use) 1.94E-03
MEI #18 SPARE MEI (Future Use) 1.94E-03
MEI #19 SPARE MEI (Future Use) 1.94E-03
MEI #20 SPARE MEI (Future Use) 1.94E-03
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SLAC NESHAPs Results
• MEI doses have been much less than 10 mrem/yr regulatory limit
• All release points at SLAC are “minor sources”• Therefore, no continuous monitoring is required
for all release points• The needed Periodic Confirmatory
Measurements (PCM) have been conducted (e.g., AMS measurements at Positron Vault and BSY in CY2006 and 2007)
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Collective Dose Calculations
NuclidesCAP88 Conversion Factor
[person-rem per Ci]CY 2006 Release
[Ci/yr]CY2006 Population Dose
[person-rem/yr]
C-11 7.63E-03 10.80 0.08
N-13 4.92E-03 101.00 0.50
O-15 1.17E-03 54.20 0.06
Ar-41 2.51E-02 2.63 0.07
Total: 168.63 0.71
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Periodic Confirmatory Measurements (PCM)
• Annual evaluation of source terms• Periodic measurements using AMS• Grab air sample
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AMS Results of Saturation Activity (mCi) in Positron Vault
(1-kW beam on positron target)
Measured AMS[mCi]
Calculated IAEA[mCi]
C-11 0 0
N-13 15 40
O-15 20 74Ar-41 1 0.5
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Model Conservatism
• We calculate the amount of radioactivity in air based on the maximum possible production rates from optimum targets, although the real situation (thick targets with significant self-absorption) could not cause maximum radionuclide production.
• The release point for each facility (e.g. for the main accelerator tunnel) is chosen to be the point closest to locations occupied by members of the public.
• For facilities that are sealed from outside atmosphere we make conservative estimates of air exchange rate (minimum one per day).
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SLAC HISTORICAL NESHAPs MEI DOSE
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
CALENDAR YEAR
MEI
DO
SE [m
rem
/yr]
MEI Dose [mrem/yr] Dose Limit [mrem/yr]
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Conclusions
• Conservative dose model• SLAC NESHAPs program is fully in
compliance with the regulation for the last 20 years
• None of single release point has exceeded the 0.1 mrem/yr SLAC reference level, and also for continuous stack air monitoring requirement
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MARS15 Particle Flux Distribution for Air Activation in IR10
(a) Cu-TD: (b) Cu-TD: nγ
Particle Flux [cm sec W ]-2 -1 -1
(a) Septum: (b) Septum: nγ
Particle Flux [cm sec W ]-2 -1 -1
(a) BAD : (b) BAD : nγ
Particle Flux [cm sec W ]-2 -1 -1