6. Procedures for Work with Radioactive Materials

Everyone who uses radioactive materials is responsible for ensuring that personnel radiation exposures are kept As Low As Reasonably Achievable (ALARA). This section includes standard laboratory best practices and procedures to accomplish this. The Radiation Use Authorization (RUA) may prescribe additional specific precautions and conditions.

6.1. Procurement Procedures

Obtain prior approval using the Radiation Safety Information System (RSIS) before procuring radioactive materials, whether procurement is by purchase, transfer, loan, or gift. Each order must be within the limits listed on the RUA or the RSIS will not generate an authorization number. EH&S RST staff will verify the authorization number is present with each purchase when it arrives, as part of their receipt survey. The order must include the authorization number so that the delivery is not delayed.

6.2. Transferring Radioactive Material

Transfers of radioactive materials may be proposed between RUAs using RSIS. All proposed transfers that fall within RUA limits will be instantly approved by RSIS.

Off-campus transfers are governed by federal and state regulations; such transfers must be made through EH&S RST. You may initiate a transfer of radioactive materials to another institution through RSIS.

6.3. Receiving Radioactive Material

All radionuclide shipments are delivered by the carrier to the EH&S- Hazardous Material Facility at 1 Frank Schlessinger Way, Berkeley, CA 94720. EH&S RST inspects each package for the following:

  • Conformance with the RUA limits, previous deliveries, and lab inventory
  • Damage to or contamination of the contents or containers
  • Conformance with Department of Transportation (DOT) and Nuclear Regulatory Commission (NRC) regulations

If the shipment passes inspection, it is delivered to the RH’s laboratory or storeroom as prearranged. The transfer is formal and the recipient signs for the materials. EH&S RST maintains records of radionuclide receipts.

Prior arrangements must be made for shipments that will not conform to the procedures described above such as the acquisition of an RPM at a specific laboratory or the direct delivery of equipment that contains radioactive sources (e.g., liquid scintillation counters, gas chromatographs, etc.).

6.4. Security of Radioactive Material

The RH is responsible for the ongoing custody and security of any radioactive material under the RUA. Any loss or potential loss of radioactive material must be reported to EH&S (510) 642-3073 as soon as possible after the loss is suspected.

Rooms containing radioactive material must be locked or under the control of RUA personnel such that measures can be effectively taken to prevent the unauthorized use or removal of the material. If non-RUA authorized users are permitted to be in the room where the radioactive materials are stored, then the radioactive material must be either under constant surveillance by RUA personnel or locked such that it cannot be used or removed by an unauthorized individual.

6.5. Restricted and Controlled Areas

controlled area is one to which access can be limited to authorized personnel in order to prevent undue risk from exposure to radiation or radioactive materials. A restricted area is one to which access is always limited to authorized personnel.

All entrances to restricted areas must remain closed and locked when not under constant surveillance by an individual trained to control the radiation hazard. Members of the public are not allowed in restricted areas without the escort of laboratory staff or EH&S staff. Details may be found in the UC Berkeley policy “Access to Laboratories Containing Hazards” available on the UC Berkeley website. All visitors must be given a safety briefing, summarizing potential hazards in the area, prior to entering a restricted area. This may be done most conveniently with a safety briefing sheet that can be handed to visitors to review and discuss with the RH or authorized user.

6.6. Inventory Control and Possession Limit

RHs must keep records and inventories of all radioactive materials under their control. Each record must include the radioisotope, quantity (in millicuries or in grams for source material or SNM), activity, date, and storage location. The on-line inventory application, RSIS, must be used for this purpose.

The inventory records should also include sufficient information to help locate the materials. This may include the location of the original stock container and other secondary vials and/or material that is in waste.

The RH must ensure periodic audits are conducted to visually verify the locations of all sealed and unsealed radioactive materials. This is normally done at the time of routine RST surveys. In all cases, a record of the inventory audit is made and preserved in RSIS. Missing radioactive material must immediately be reported to the RST. The RSO will inform CDPH, as required.

If source, special nuclear material, or nationally tracked sources are used, special inventory, physical protection, and reporting requirements apply. Special nuclear material must be inventoried in January and July of each year in accordance with EH&S RST procedures. Any apparent discrepancy of more than one gram must be immediately reported to the RSO. Source material must be inventoried each September and discrepancies of more than 500 grams must be immediately reported to the RSO. Transfer or disposal of special nuclear material, source material and nationally tracked sources must be coordinated with the RSO due to special security and federal reporting requirements.

6.7. Posting Requirements for Radiation Laboratories

Approved radiation-warning signs are required where the potential for exposure to radiation exists.

At minimum, the RH must ensure the following are properly posted:

  • Caution Trefoil Signs: All entrances must be posted with a sign bearing the radiation caution symbol and the words, “CAUTION: RADIOACTIVE MATERIAL(S).” for radioactive materials laboratories.
  • Current RUA: A current approved version of the RUA or a posting which identifies where the current approved version of the RUA can be viewed must be posted in the laboratory.
  • A copy of the Radionuclide Emergency Procedures provided by EH&S RST.
  • EH&S RST may also post “CAUTION: RADIATION AREA” or “CAUTION: HIGH RADIATION AREA” signs as appropriate.

6.8. Labeling Requirements

6.8.1. Labeling Containers

  • Vials and containers must be labeled to indicate that they contain radioactive material. (planchets and vials containing counting samples are exempt from this requirement.)
  • When double containers are used, both inner and outer containers must be labeled (unless the inner label is visible from the exterior).
  • Labeling requirements also apply to radioactive waste. The radionuclide and the approximate amount of radioactivity must also be posted on the radioactive waste container.

6.8.2. Labeling Equipment

Equipment-labeling requirements depend on the relative permanence of the operation. If an apparatus emitting more than twice the background amounts of radiation will be turned on or in use for eight hours or more (or overnight), it must be labeled.

6.8.3. Labeling Work Areas

All work areas used in radionuclide procedures (including tabletops, equipment, and storage areas such as refrigerators) must be labeled. “Radioactive Material” caution tape should be used to clearly delineate the area(s) you plan to work in. At least one bench or area label should identify the radioisotope(s) being used in that area, and must contain a radiation symbol (trefoil) with text that reads, “Caution: Radioactive Material.”

6.8.4. Labeling Sealed Sources

Unless impractical, label the sealed source, its shield, or the apparatus in which the source is mounted with a permanent radiation warning sign. Unless otherwise indicated, the sealed source should also be labeled with the radioisotope, initial activity, and the date of initial activity.

6.8.5. Requirements for Removal of Labeling and Posting

Prior to sending equipment previously used in radioactive materials research (e.g., centrifuges, refrigerators, etc.) for repair or disposal, and prior to discarding packaging materials from radioactive shipments, users must:

  • Survey them appropriately and determine that they are free of contamination. Maintain records of any surveys performed to release equipment for repair or disposal. Alert the RST of your plans to return this equipment so they can confirm that the object is free of contamination.
  • Remove or deface all radiation labels and posting.

6.9. Radiation Exposure and Contamination Control in the Laboratory

The level of radiation control assigned to an RUA is determined by the RSO and reflects at least the following: (1) the internal radiotoxicity of the materials authorized under the RUA, (2) the external radiation exposure hazards, (3) the complexity of procedures, and (4) the physical and chemical characteristics of the material used. Specific controls are noted on each RUA.

6.9.1. Internal Contamination

Internally deposited radionuclides (internal contamination) are a matter of concern. Internal uptake is best avoided by using proper containment techniques, minimizing surface contamination, using appropriate personal protective equipment (PPE), and using proper engineering controls.

To prevent internal contamination, the following precautions must be taken when working with unsealed radioactive materials.

  • Do not eat, drink, smoke, or apply cosmetics in restricted areas where unsealed radioactive materials are stored or used.
  • Do not pipette radioactive materials by mouth; use mechanical methods.
  • Use a fume hood for handling any radioactive material that may become airborne.
  • Wear appropriate personal protective equipment (PPE), (e.g., safety glasses, face shield, gloves, Lab coats, closed-toed shoes, pants.)
  • Perform contamination surveys during the course of the experiment and immediately upon completion.

6.9.2. Food and Drink Policy in Laboratories that Use Radioactive Materials

Consumption or storage of food and drink is not allowed in radiation use laboratories. Exceptions may be granted on a case by case basis by the campus Radiation Safety Committee (RSC) if the use is consistent with policy on other laboratory hazards.

6.10. Best Practice: Overview: General Radiation-Control Techniques

The following are general procedures for radiation control in a radionuclide laboratory:

  • Do not bring personal belongings, other than those required for work, into the laboratory.
  • Separate radiation work and storage areas from general personnel spaces. Store your lab coat away from your personal clothing.
  • Do not eat, drink, smoke, or apply cosmetics in the laboratory where unsealed radioactive materials are present unless a designated “Clean Area” has been established.
  • Cover work areas with absorbent paper to protect against spills. Use a spill tray when working with large volumes of liquids.
  • Use appropriate shielding.
  • Put waste materials in appropriate containers and keep liquid waste in secondary containment.
  • Maintain good housekeeping in the laboratory.
  • Restrict public access and properly control access by minors.
  • Use appropriate signs.
  • Wear impervious gloves and use tongs.
  • Use mechanical (remote) pipetting techniques.
  • Do not work with radioactive materials if you have an open skin wound.
  • Wear appropriate PPE over street clothes (e.g., fire-resistant clothing if working with flammable materials).
  • Clearly label contaminated glassware or equipment until it has been decontaminated.
  • Use fume hoods when working with volatile materials.
  • Label work areas, materials, and/or containers as required.
  • Survey radiation-use areas with an appropriate survey technique (e.g., survey meter or area “wipe test”), performed and documented at the frequency specified on the RUA.
  • Use radiation-detection equipment during manipulations of unsealed radionuclides to detect and prevent the spread of contamination.
  • Check gloves, forearms, and other PPE for contamination frequently.
  • If contamination is suspected in the course of work, monitor the area using a suitable survey meter or area wipe, and decontaminate if necessary.
  • Wash your hands and check them with a suitable survey meter before leaving the laboratory.

6.11. Additional Requirements for “High” and “Very High” Radiotoxicity Nuclides

If you will be working with radionuclides with high or very high radiotoxicity, as defined in Appendix 1- Table 5, your RUA will note that fact and additional precautions will be required. The following should be considered:

  • Pre-plan the operation in detail and consult with the RST.
  • Decide on actions required in case of emergencies.
  • Perform dry runs without any radioactivity if the procedure is new or unfamiliar to you.
  • Develop the skills necessary to satisfy the special needs of the project.
  • Inform personnel working with radioactive materials (and those who could be affected by incidental exposure or accidents) of safety practices and emergency procedures.
  • Have all project participants wear personnel monitors if dosimetry is specified on the RUA.
  • Frequent monitoring of all areas and operations.

6.12. Laboratory Self-Surveys/Checks

Contamination is most easily detected by conducting routine monitoring surveys to detect excessive radiation and/or contamination levels. This alerts laboratory personnel to potential hazards. Survey requirements are specified on the RUA. Table 3 below lists methods and instruments recommended for the detection or measurement of radioactive materials.

Table 3. Recommended Radiation Detection Instruments

Radiation Type Energy Isotope examples Detector
Alpha All Am-241, Cf-252, special nuclear material

ZnS scintillation

Proportional counter


Beta < 60 KeV H-3 Wipe—LSC
≥ 60 KeV C-14, S-35, P-33, P-32, source material

Pancake GM

Proportional counter


Gamma or X-ray < 200 KeV Cr-51, I-125 Am-241

Thin Sodium Iodide scintillation


Energy compensated GM

Ion Chamber

≥ 200 KeV Na-22, I-131, Cr-51 Cs-137, Ra-226

Thick Sodium Iodide scintillation


Calibrated GM

Ion chamber

Solid state detectors

Neutron All PuBe, AmBe accelerators

Proportional counter

Neuron detectors

6.13. Survey Frequency

Routine monitoring should occur during and following all active work with dispersible sources of radioactive materials. Additionally, self-surveys shall be documented at minimum once a month or more frequently as warranted by the nature of the work. If more frequent documented self-surveys are required, it will be noted in your RUA.

6.13.1. Survey records

Keep permanent written records of all survey results, including negative results.

For radioactive materials RUAs, the surveys must include:

  • Location, date, and radiation detection instruments used (model and serial number)
  • Name of person conducting the survey.
  • Map of the surveyed area, with identifying relevant features such as active use, storage, and waste areas.
  • Measured exposure rates and/or contamination levels, keyed to a location on a map of the area.
  • Corrective action taken, if contamination or excessive exposure rates were found, and the reduced levels after corrective action.

Where required, RHs must maintain permanent written records of such surveys and tests.

6.14. Decontamination Requirements

Laboratory surfaces, equipment, and clothing may become contaminated in spite of proper precautions. Such contamination does not necessarily present a serious hazard. This is especially true if it is (1) detected promptly, (2) not allowed to spread or be ingested, and (3) removed, to prevent cross-contamination to other surfaces and objects.

The RH or designee is responsible for seeing that decontamination is carried out properly and that personnel are instructed in decontamination procedures. EH&S RST provides assistance or supervision in cases of personal contamination or significant levels of contamination. When decontaminating:

  • Wear appropriate protective clothing (gloves, lab coats, etc.).
  • Confine the spread of contamination, starting from areas of low contamination and working toward areas of higher contamination.
  • When cleaning a work surface with a decontamination solution, always clean from the outside of the contaminated area working inward towards the center. Use a fresh paper towel with each pass and don’t wipe the area in a circular fashion.
  • Carefully remove all loose or easily removable contamination, then wash with soap, detergent, or special solvents.
  • Place used cleaning materials (e.g., absorbent materials, gloves, etc.) in a labeled radioactive waste container.

Glassware and other contaminated equipment should be cleaned using laboratory detergents, acids, or cleaning solutions as appropriate. Contaminated equipment (e.g., pipettes, centrifuge rotors, etc.) can be soaked in a decontamination solution overnight to improve the removability of contamination. All equipment that is to be disposed of and is contaminated with long-lived radionuclides, and that cannot be cleaned to acceptable levels, must be disposed of as radioactive waste. Equipment contaminated with short-lived radionuclides and being stored to allow for radioactive decay must be clearly identified and stored in a secure location.

Material and equipment exposed to unsealed radioactive material must be thoroughly decontaminated and properly surveyed to confirm the absence of residual radioactive material before it is released for unrestricted use. Proper survey equipment and techniques must be used and the results documented before the material is released. The RST should be consulted for any questionable situations or complex equipment like liquid scintillation counters and gas chromatographs that might contain sealed sources or contamination.

Hazardous and radioactive materials cannot be sent to Overstock for release to the public.

Contact the RST for questions related to the disposal of radioactive material.

6.15. UC Berkeley Contamination Limits

Levels of contamination on radioactive work surfaces, equipment, and facilities should be kept as low as reasonably achievable (ALARA). Maximum acceptable levels of contamination are listed in Table 4 below. These levels can be determined by the use of an appropriate survey meter or area wipe. Workplace surfaces and floors that cannot be decontaminated to acceptable levels should be brought to the attention of the RSO to determine how they will be addressed.

Table 4. UC Berkeley Contamination Limits

Type of Surface
(All values in dpm/100 cm2 )

Total Removable and Fixed Removable α Removable β, X or γ
High and Very High Toxicity*
Removable β, X or γ
Low and Moderate Toxicity*
Restricted and Controlled Areas
Within posted radioactive materials zones 1,000 α
10,000 β, X or γ
200 2,000 10,000
Outside posted radioactive materials zones 100 α
1,000 β, X or γ
20 200 1,000
Skin, personal clothing, and protective clothing Not statistically different from background. Typically this means less than twice the background count rate with an appropriate sensitive contamination survey instrument.
Unrestricted Areas
All surfaces, including items removed from restricted and controlled areas and “trash” Not statistically different from background.

*See Appendix A section 1.2 for specific radiotoxicity values.

α = alpha

β = beta

X = X-ray

γ = gamma

6.16. Sealed Sources

  • A physical inventory of licensed sealed sources is required to be completed and documented once every six months.
  • Most sealed sources must be leak tested every six months. The RST will perform these tests and advise the RH of the results and any actions that should be taken.
  • In many cases, only vendor representatives are authorized to remove or replace sealed sources installed in manufactured devices. Contact EH&S RST for assistance.