SLAC Radioactive Air (NESHAPs) Program · SLAC Radioactive Air (NESHAPs) Program Henry Tran ......

1

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)

2

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

3

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.

4

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

5

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

7

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

8

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 #11 Asymmetric B-Factory, Region 08 (PEP-II-R08) 1195 -229




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

11

Souce & MEI Locations (Main Campus)

12

Souce & MEI Location (Mid Section)

13

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

17

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

6

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

6

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





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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


(a) BAD : (b) BAD : nγ


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