The Catholic University of America

Radiation Safety Manual

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APPENDIX D: Disposal of Radioactive Waste and Surplus Radioactive Sources

D-1 Definition

Radioactive waste (radwaste) is defined to mean:

  1. Unsealed radioactive material, regardless of chemical or physical form, whose retention is no longer desired by the responsible Authorized User,
  2. Material or equipment that is contaminated , or is presumed to be contaminated because of its use in association with radioactive material (e.g., disposable gloves and other protective clothing, glassware, tray and bench covers, tools, etc.),
  3. Sealed sources of radioactive material which have been determined by the RSO to be leaking beyond allowable limits or reduced below useful activity through radioactive decay.

D-2 Introduction

This Appendix provides detailed instructions for the handling of all radwaste generated on the CUA campus, from its initial generation in the laboratories of Authorized Users until it is lawfully removed from the campus. Radwaste shall be disposed of only in accordance with the provisions of this Appendix. Specifically radwaste shall NOT be:

  1. Incinerated on the CUA campus,
  2. Buried on the CUA campus,
  3. Deposited in ordinary trash containers,
  4. Transported off campus except by duly licensed persons, or
  5. Discharged to the sewer via laboratory sinks.

D-3 Disposal to the Sewer

The RSO is authorized to release radioactive waste to the sewer in accordance with applicable regulations. Users shall not release radioactive material to the sewer except that incidental to the routine cleaning of laboratory equipment.

The RSO shall maintain a log of all radioactive waste released to the sewer. The record shall include the release date, the isotope, and the activity of the release.

D-4 Release to Ventilation Exhaust Systems

D-4.1 Release Control

All operations in which significant atmospheric radioactive contamination could be produced shall be performed using local air filtration, a glove box, a fume hood, or combination thereof as set forth in the User Authorization.

D-4.2 Releases to Outdoor Air

In the case of a duct exhausting directly to the atmosphere (e.g., fume hood or glove box exhaust), the RSO shall be notified immediately if there is a release of airborne radioactive material in concentrations which, if averaged over a period of 24 hours would exceed the limits specified for the material in 10 CFR 20, Appendix B, Table II, Column 1.

D-4.3 Permissible Averaging Time

Determinations of the average concentration of radioactive material may be made with respect to the point where the material leaves the exhaust duct. Concentrations may not be averaged over a period longer than 24 hours without prior authorization of the RSC.

D-5 Specific Disposal Instructions for Radwaste

All radwaste shall be segregated into special collection containers in accordance with the rules contained in this Section.

D-5.1 Definitions

For waste management purposes, radwaste shall be categorized by class and isotope. Five classes will used: Animal, Aqueous, Dry, LSC, and Organic

  1. Animal: Animal carcasses contaminated with radioactive material (internally and/or externally).
  2. Aqueous: Liquid radwaste whose primary solvent is water. It may contain dissolved or suspended organic matter.
  3. Dry: Radwaste, except used liquid scintillation vials, which contains no free liquid, either because the material is "dry" in the conventional sense or because an approved material has been added to absorb small quantities of free liquid which may be present.
  4. LSC: Liquid scintillation cocktail which contains radioactive material.
  5. Organic: Radwaste whose solvent(s) consist solely of organic liquid(s). It may contain dissolved or suspended inorganic matter. It shall not include scintillation cocktail, whether radioactive or not.

D-5.2 Segregation

The Authorized User is responsible for segregation of radwaste by class and within class; by isotope. LSC waste shall also be segregated by product name and labeled as "water soluble or "not water soluble."

D-5.3 Radwaste Containers in Use

  1. Containers employed for temporary accumulation of radwaste shall be:

    • Distinctively different from trash containers used for non-radioactive trash;
    • Conspicuously marked on opposite sides with the radiation symbol (10 CFR 20.1901), together with the words "Caution - Radioactive Material";
    • Conspicuously labeled to indicate the class of radwaste and the isotope which is contained;

D-5.4 Exposure Limitation

  1. Controlled Areas

    The total amount of radwaste placed in any container shall be controlled so that the radiation exposure at one foot from the container is less than 2 mrem/hr and the exposure at contact with any surface of the container is less than 5 mrem/hr.
  2. Restricted Areas

    The total amount of radwaste placed in any container shall be controlled so that the radiation exposure at one foot from the container is less than 5 mrem/hr and the exposure at contact with any surface of the container is less than 10 mrem/hr.

D-5.5 Precautions Against Chemical Reaction

Material shall not be put into a radwaste collection container if there is any possibility of a chemical reaction during storage which might cause fire or explosion, or cause the release of chemically toxic or radioactive gases. Solutions shall be adjusted to pH 6-8 prior to disposal into a liquid container.

D-5.6 Animal Carcasses

Small animal carcasses containing administered radionuclides shall be placed in sealed plastic bags, tagged with the date of disposal, animal type, the isotope and the total activity in millicuries. The carcass shall then be stored in an appropriately labeled freezer until the isotope decays to background levels or arrangements have been made with the RSO for disposal by a licensed commercial firm.

D-5.7 Labeling

Upon completion of accumulation, a radioactive material label shall be affixed to each container of radwaste. The label shall bear the following minimum information:

  • the date the package or container was prepared,
  • the name of the Authorized User,
  • the waste class, and
  • the isotopes contained and their total activity (in millicuries).
Labels on containers of LSC waste shall also include the commercial or product name of the cocktail and state whether or not the cocktail is water soluble. LSC waste containing only H-3 or C-14 activity shall also state on the label whether the activity concentration is "LOW" (<50 nCi/gm) or "HIGH" (>50 nCi/gm).

D-5.8 Removal

Radwaste properly packaged and labeled will be picked up from individual laboratories by the RSO and transported to the CUA radwaste storage and handling facility for interim management and ultimate shipment to a licensed low level waste site. Requests for pick up of radwaste can be placed with the RSO by calling the Radiation Safety Office (ext. 5206).

D-5.9 Storage

The RSO is authorized to store radwaste in the CUA Radioactive Materials Storage Facility (RMSF), for the purpose of accumulating shipments of economical size for transport to a licensed low level waste site. In the event that access to a low level waste site is denied, the RSO is authorized to store radwaste in the RMSF until site access is restored.

D-5.10 Storage for Decay

In accordance with the provisions contained in the byproduct license, the RSO is authorized to store- for-decay in the CUA Radioactive Materials Storage Facility (RMSF), radwastes that contain only isotopes of short half-life (T½ <65 days).

D-6 Disposal of Surplus Radioactive Sources

D-6.1 Sources Surplus to the Needs of an Authorized User

A radioactive source, other than consumable radioactive material, which is surplus to the needs of an Authorized User, may be transferred to another Authorized User in accordance with Section 9.2.9 of this manual, or transferred to the RSO.

D-6.2 Sources Surplus to the Needs of the University

The RSO may take the following action with respect to a radioactive source, other than consumable radioactive material, which is transferred as surplus by an Authorized User:

  1. Transfer the source to another Authorized User who has a need and an Authorization for it,
  2. Retain the source for the University,
  3. Dispose of the source in accordance with applicable regulations and/or loan agreements (in cases where the source is not owned by CUA).