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Release of Materials at ORNL

Release of Materials at ORNL. Donald C. Gregory Radiation Safety Officer SNS/ORNL. Scope of Radiological Release/Disposition. Metals From “Radiation Areas” From other areas Potentially Activated Materials Activation calculation and/or PK NaI and Pancake survey Release Criteria

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Release of Materials at ORNL

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  1. Release of Materials at ORNL Donald C. Gregory Radiation Safety Officer SNS/ORNL

  2. Scope of Radiological Release/Disposition • Metals • From “Radiation Areas” • From other areas • Potentially Activated Materials • Activation calculation and/or PK • NaI and Pancake survey • Release Criteria • Authorized Limits process for samples • In theory • In Practice

  3. Metals • Moratorium/Suspension applies, and is the responsibility of the material owner • Scrap metal for recycle is accumulated in separate dumpsters • Salvage sales of metal (including to individuals) is allowed • Recycle is not economical considering purchase price • Consistent with FAQs from EH-412

  4. Potentially Activated Materials • A specific activation calculation is preferred • Very conservative total activity limits • < 1000 dpm for powders/liquids • < 5000 dpm for solids • < 10000 dpm for tritium • Alternative – general Process Knowledge • Material is uniform composition • Likely dominant activation products are NOT alpha/beta emitters • Item was uniformly exposed or max-exposed surface is visible • Survey each item with NaI and GM • Results must be < Lc • Checking for bulk gamma and surface beta/gamma

  5. Authorized Release Limits for Samples • Release Limit most restrictive of: 1 mrem/y, DOT, NRC • Following pathway protocol used by ANSI N13.12-1999 • 39 isotopes in the original proposal • With notification to DOE, isotopes list was greatly expanded • 0.1 microcuries (default) most common limit • Public Notification includes wording changes in research agreements with participating organizations • Release requires activation calculation and a confirming measurement with shielded NaI • User is given an activation/measurement form

  6. Authorized Release Complications • Activation Calculations may be overly conservative if User does not use accurate exposure time/spectrum • Released samples may not be accepted as “non-rad” • Internal to ORNL – loss of sample identity may make it radioactive material or contamination despite release • External Institutions with Agreements – despite agreement, they may not accept ANY level of activation • Implementation requires careful coordination • Who brings all the pieces together? • Who takes responsibility? • What about samples that do not qualify for release?

  7. What is the better solution? • DOE sites need unified and consistent criteria for release of potentially activated/bulk contaminated materials • Current efforts are still site-specific and ad hoc • Adoption of ANSI N13.12-1999 for both surface and bulk material release by DOE would be an improvement • Consistent approach based on pathway analysis • DOE currently has no criteria for release of bulk material • Current DOE surface contamination limits are based on detection capability

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