Managed by UT-Battelle for the Department of Energy Authorized Limits Request for Release of Neutron Scattering Experiment Samples From SNS and HFIR Donald C. Gregory Spallation Neutron Source Oak Ridge National Laboratory

2Managed by UT-Battelle for the Department of Energy Presentation_name The Problem  Thousands of User-supplied experimental samples will be exposed to neutrons at SNS and HFIR every year during experiments –Materials include powders, liquids, crystals, and solids –Many samples weigh grams to 10s of grams  DOE has no Authorized Limits for release of materials activated in bulk – no matter how slight!  Samples are often examined after exposure, or used in additional experiments at other facilities  It is highly inconvenient to require license information and special handling for items that are not measurably activated

3Managed by UT-Battelle for the Department of Energy Presentation_name The Solution  DOE allows sites to apply for specific permission (“authorized limits”) to release items with volumetric contamination –Order governs release to the Public and Environment –Draft Guide XX outlines the application process  Key requirements –Maximally exposed individual < 1 mrem/y –Collective dose < 10 person-rem/y –Total activity less than other regulatory triggers –Independent verification –Stakeholder communication  Apply to local DOE office –DOE-HQ has a chance to comment or review –In practice, DOE consults during application development

4Managed by UT-Battelle for the Department of Energy Presentation_name ORNL Proposal  Qualifying samples from SNS and HFIR will be released without radiological restrictions  Release is based on total activity in the sample, based on both PK and measurement  Activity categories for isotope-specific release thresholds are based on pathway analysis  Methodology to add isotopes is detailed

5Managed by UT-Battelle for the Department of Energy Presentation_name Initial Release Table Radionuclide Group Description Authorized Limit for Release for Unrestricted Use Group AUranium Isotopes: U-234, U-235, U µCi Group BHigh Dose Beta-Gamma Emitters: Na-22, Si-32, Mn-54, Co-60, Fe-60, Zn-65, Sr-90, Nb-94, Ru- 106, Ag-110m, Sb-124, I-129, Cs-134, Cs-137, Eu-152, Eu-154, Ir-192, and others (a) 0.1 µCi Group CLow Dose Beta-Gamma Emitters: Cr-51, Co-58, Fe-59, Sr-89, Cd-109, In-111, I-125, I-131, Ce- 144, and others (a) 1.0 µCi Group DOther Beta-Gamma Emitters: C-14, S-35, Cl-36, Ca-45, Fe-55, Ni-59, Ni-63, Tc-99, Pm-147, and others (a) 10.0 µCi Group ETritium H µCi

6Managed by UT-Battelle for the Department of Energy Presentation_name Pathway Analysis Scenarios (using RESRAD-BUILD)  Average researcher –2 hr/day in lab with sample (1.4 m average distance) –External gamma exposure, inhalation, ingestion  Extended researcher –8 hr/day in lab with sample (1.4 m distance) –External gamma exposure, inhalation, ingestion  Spill/Release Conditions –Spilled sample (powder or liquid) –Contaminates 1 m2 area –Exposure for a work-month (160 hrs)

7Managed by UT-Battelle for the Department of Energy Presentation_name Basis for Release - PK  Sample Activation Calculation Tool –User initiated as part of application process –Input - sample composition (elements by %) –Input - beamline, exposure duration, and power –Program supplies neutron energy profile –Program calculates activation products –Total activity, product isotope list, and decay time to 2 mrem/h is supplied in the output –Additional specialized output can be developed

8Managed by UT-Battelle for the Department of Energy Presentation_name Basis for Release - Measurement  RCTs confirm total activity using standard survey instruments –Typically NaI to detect gammas  If PK and/or measurements indicate total activity near the release limit, additional verification will be employed  Exploring Activation Tool output options to predict measurement results

9Managed by UT-Battelle for the Department of Energy Presentation_name Speed Bumps  DOE has never (to my knowledge) approved an application of this kind for release without restriction –Activation Tool is a unique and powerful advantage for this application  DOE typically reviews implementing procedures –Revisions to the measurement process are anticipated with experience

10Managed by UT-Battelle for the Department of Energy Presentation_name Where are We Now?  Draft application is being reviewed by ORNL and DOE  Implementing procedures are in flow- diagram stage  Final submittal is anticipated in October  The entire application process has been led by George Stephens of ORNL’s Nuclear and Radiological Protection Division