Authorized Limits Request for Release of Neutron Scattering Experiment Samples From SNS and HFIR

1. Authorized Limits Request for Release of Neutron Scattering Experiment SamplesFrom SNS and HFIR Donald C. Gregory Spallation Neutron Source Oak Ridge National Laboratory

2. 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 Presentation_name

3. The Solution • DOE allows sites to apply for specific permission (“authorized limits”) to release items with volumetric contamination • Order 5400.5 governs release to the Public and Environment • Draft Guide 441.1-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 Presentation_name

4. 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 Presentation_name

5. Initial Release Table Presentation_name

6. 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) Presentation_name

7. 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 Presentation_name

8. 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 Presentation_name

9. 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 Presentation_name

10. 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 Presentation_name