Radioactive Waste Disposal at UVM

UNIVERSITY OF VERMONT

RADIATION SAFETY OFFICE

STANDARD OPERATING PROCEDURES

FOR

RADIOACTIVE WASTE DISPOSAL

INTRODUCTION

The use of radioactive materials results in a certain amount of waste. UVM is the second largest producer of radioactive waste in Vermont. We handle about 900 cubic feet per year out of which only 250 cubic feet are sent for burial. The cost of disposal for burial is very high. Since 1/1/89, we have been unable to ship the waste and it must be stored on campus until the State of Vermont finds a solution. Careful planning on the part of research laboratories will reduce the volume of waste and the cost of disposal.

IS IT RADIOACTIVE ?

All packages containing radioactive materials are received at the RSO and checked for contamination. The outer package and packing materials are discarded as non-radioactive waste. Only the vial containing the radioactive chemical is radioactive and must be handled carefully. Store the radioactive material in a protected place along with the log sheet provided by the RSO. Use the log sheet whenever you remove radioactive solution from the container. The log sheet must be brought to the RSO when that radioactive container is finished along with all of its radioactive waste.

Do not discard non-contaminated trash such as coffee cups, soda containers into radioactive waste containers. Use disposable gloves while handling any radioactivity. Use trays and absorbent papers to minimize the spread of contamination in work areas.

All laboratory equipment used with isotopes can become contaminated. All contaminated materials must be discarded as radioactive waste if they cannot be decontaminated.

A liquid scintillation counter with wipe testing is necessary to check for contamination from low energy beta emitters like ³H, ¹⁴C, and ³⁵S. A survey meter with a Geiger-Müller (GM) detector may be used to check contamination due to high energy beta emitters like ³²P and a Sodium Iodide (NaI) crystal detector may be used for gamma emitters like ⁵¹Cr and ¹²⁵I. Any reading above background must be considered radioactive. Take a "background" reading of the instrument at a location away from the radiation sources.

CAN RADIOACTIVE WASTE BE DISPOSED THROUGH SANITARY SEWER, NORMAL TRASH, OR INCINERATION ?

The University's administration does not permit any radioactive materials to be disposed through sanitary sewer or by incineration. Any exceptions requires specific approval from the University Radiation Safety Committee, the University Provost, and the Vermont State Commissioner of Health.

INTO WHAT CATEGORIES SHOULD WASTE BE SORTED ?

A. WASTE FOR BURIAL - LONG LIVED WASTE (HALF LIFE >90 DAYS)

DRY WASTE

(Ultimate destination: burial site)

half-lifes > 90 days
Solid waste (gloves, pipettes, absorbant paper, plastics, glassware, etc.)
No absorbed or pourable liquid of any kind
No animal carcasses
No biological material
No viable pathogenic or infectious agents
No organic solvent contamination
< 0.1% chelating agents (i.e. EDTA, DTPA)

WET WASTE

(Ultimate destination: burial site)

half-lifes > 90 days
Solid waste with a small volume of liquid associated with it (less than 50 ml/vial or tube)
No viable pathogenic or infectious agents
No organic solvents
< 0.1% chelating agents (i.e. EDTA, DTPA)

ANIMAL WASTE

(Ultimate destination: burial site)

Solid animal carcasses only
< 0.1% chelating agents (i.e. EDTA, DPTA)

LIQUID WASTE

(Ultimate destination: burial site)

half-life > 90 days
bulk liquid (greater than 50 ml)
Aqueous liquid waste only with a pH between 6 and 9
may include excreta
No liquid scintillation fluids or organics
< 0.1% chelating agents (i.e. EDPA, DTPA)

B. WASTE FOR INCINERATION - LOW LEVEL (SCINTILLATION FLUID)

EXEMPT LIQUID SCINTILLATION VIALS OR BULK LIQUID

(Destination: Quadrex in Florida).

Liquid scintillation cocktail containing ≤ 0.05 μCi/ml. (111,000 disintegrations/ minute/milliliter) of ³H or ¹⁴C.

MIXED LIQUID SCINTILLATION VIALS

(Destination: Quadrex in Florida)

Waste consisting entirely of vials containing liquid scintillation fluid containing;

³H and ¹⁴C in concentrations ≤ 0.05 μCi/ml.

²²Na, ³²P, ³⁵S, ⁴⁵Ca, ⁵¹Cr, ⁵⁷Co, ⁵⁹Fe, ⁶⁵Zn, ⁷⁵Se, ¹⁰⁹Cd, ¹²⁵I, ¹³¹I and ¹⁴¹Ce in concentrations ≤ 0.001 μCi/ml.

REGULATED LIQUID SCINTILLATION VIALS

(Destination: Quadrex in Florida)

Waste consisting entirely of vials containing liquid scintillation fluid containing;

³H and ¹⁴C in concentrations ≤ 0.05 uCi/ml.

²²Na, ³²P, ³⁵S, ⁴⁵Ca, ⁵¹Cr, ⁵⁷Co, ⁵⁹Fe, ⁶⁵Zn, ⁷⁵Se, ¹⁰⁹Cd, ¹²⁵I, ¹³¹I and ¹⁴¹Ce in concentrations ≤ 300 μCi/ml.

C. WASTE FOR DECAY - SHORT LIVED (HALF LIFE <90 DAYS)

LIQUID WASTE

(Ultimate destination:normal trash-landfill)

half-life ≤ 90 days
Aqueous liquid waste only with a pH between 6 and 9.
may include excreta.
No liquid scintillation fluids
< 0.1% chelating agents.

SOLID WASTE

(Ultimate destination: normal trash-landfill)

half-life ≤ 90 days
Solid waste
No animal carcasses
No biological material
No pathogenic or infectious agents
No organic solvent contamination

If there is space available in your laboratory, you can store short-lived radioactive waste and allow it to decay to background at no cost. We prefer, however, that you bring all radioactive waste to the RSO. If you do not have the space to store, you can bring the waste to the RSO and it will be stored for decay at the Spear Street Low-Level Radioactive Waste Facility.

The general rule is that you have to store the material for at least ten half-lives. The fraction of activity remaining after ten half-lives is equal to 1/1000 of the original activity. For example, if the original activity equals 1 mCi, after ten half-lives of decay the activity will be equal to 0.001 mCi (or 1 microcurie).

The following table illustrates the activity remaining after ten half-lives of decay:

Original Activity	Remaining Activity - after 10 half-lives	remaining activity in dpm
10 mCi	10 uCi	22,200,000.
1 mCi	1 uCi	2,220,000.
100 uCi	0.1 uCi	222,000.
10 uCi	0.01 uCi	22,200.
1 uCi	0.001 uCi	2,220.

Following is a list of short-lived radioisotopes with half-lives less than 90 days which may be stored for decay:

Radionuclide	Half-live in days	Elapsed Time for 10 Half-lives
Be-7	53.3 days	1 year, 5 months and 18 days
P-32	14.3 days	4 months and 23 days
S-35	87.2 days	2 years, 4 months and 22 days
Cr-51	27.7 days	9 months and 7 days
I-125	60.2 days	1 year, 7 months and 27 days

WHAT ARE THE PROCEDURES TO FOLLOW TO STORE & DISPOSE OF

SHORT-LIVED WASTE IN YOUR OWN LABORATORY ?

The following procedure must be followed if you want to store radioactive waste of short-lived isotopes before disposing as "non-radioactive" waste :

Use copies of the "Decayed Radioactive Waste to Normal Trash" (attached) form to manifest the bags or bottles of radioactive waste being stored for decay.
Store the solid waste in yellow 5, 20, or 32 gallon plastic containers provided by the RSO. Deface all radioactive signs before disposing any waste into the bag. When the bag is full, close the bag and put a "Caution Radioactive Materials" label with date, isotope, approximate radioactivity, and surface radiation level.
Store liquid waste in 5 gallon plastic containers provided by the RSO and label with a "Caution Radioactive Materials" sign. When full, label them with date, isotope, counts per minute per milliliter.
Store the radioactive waste for at least ten half-lives in a safe place.
On the disposal day, survey the solid waste bag with a suitable instrument for external radiation levels. For liquid waste count a milliliter of liquid in a suitable counter.
The activity and the radiation level must be equal to background.
Remove or deface all "Caution Radioactive Materials" signs, labels, and tape.
Depending upon the chemicals involved, dispose the decayed waste appropriately. If toxic or hazardous chemicals are involved, then the waste must be disposed through UVM hazardous chemical pick-up. Contact the Risk Management (656-3242). If there is no toxic or hazardous chemicals and if the radioactivity is equal to background, then the waste can be disposed through normal trash or sewer.
Record all the data on the "Decayed Radioactive Waste to Normal Trash" form and send a copy to RSO.

C. NON-DISPOSABLE RADIOACTIVE WASTE: (No disposal or recycling sites available.)

At present, low level (liquid scintillation cocktail) waste containing concentrations of ³H or ¹⁴C > 0.05 uCi/ml, and the isotopes ⁷Be, ⁵⁵Fe, ⁶⁰Co, ⁶³Ni and ⁹⁵Nb are not acceptable by commercial vendors for disposal.

Please make every attempt to avoid using these isotopes in liquid scintillation fluid. If you must use them, contact the RSO for further details.

WHO SHOULD HANDLE THE WASTE ?

The investigator must appoint an individual who is certified to use radioactive materials to be responsible for the waste in the lab.

WHERE DO YOU STORE WASTE ?

Store the radioactive waste in a place away from all personnel and counting instruments. Inform the other workers and housekeeping staff about the radioactive waste storage areas.

Store the liquid waste in gallon bottles away from traffic with sufficient absorbent materials around it to contain any spill. Do not store the bottles on the floor.

The waste storage area must be wipe tested monthly to make sure that there is no significant contamination and an area survey should be made to measure the radiation level (see RSO).

HOW FREQUENTLY SHOULD WASTE BE BROUGHT TO THE RSO ?

Do not accumulate radioactive waste indefinitely. The cost of disposal continues to increase dramatically. The longer you wait to dispose the more it will cost. Keep your lab clean by bringing the waste to RSO every Friday.

HOW DO YOU TO STORE THE WASTE ?

Dry, Wet and/or Solid: in 5, 20, or 32 gallon size yellow plastic containers provided by the RSO. Also, specialized plexiglass boxes for P-32can be used.

Animal: in thick plastic bags of 1 gallon size(in freezer).

Liquid: in 1 gallon screw cap glass bottle or 5 gallon white plastic containers (depending on the category of Waste.

Liquid Scintillation Vials: in cardboard carrier trays.

WHAT LABELS SHOULD BE USED WITH WASTE ?

Use "Caution Radioactive Materials" and "Caution Radioactive Waste Do Not Empty" labels on radioactive waste containers (available from RSO). It will help other personnel in the lab and the housekeeping staff to be cautious about those containers.

APPOINTMENTS

Phone the RSO 656-2570 several days in advance to make appointments to bring the waste. Time slots are available every half-hour during normal working hours on Fridays. When Friday falls on a holiday, waste will be handled on the next regular work day.

HOW DO YOU TRANSPORT WASTE TO THE RSO ?

You will not need to transport the radioactive waste. Call the RSO and we will come and pickup the waste for you. Just let us know what category and volume of radioactive waste you have to be picked up.

HOW DO YOU FILL OUT THE MANIFEST ?

The upper section is for solid short lived radioactive waste only.

The middle section is for dry, wet, or animal long lived radioactive waste.

The lower portion is for bulk liquid and liquid scintillation vials. Fill out the chemical form, vial size (if applicable), isotope, average counts per minute/ml, counting efficiency, disintegration per minute/ml, concentration (in microcuries/ml) and the number of gallons or vials.

WHAT CAN BE COMPACTED BY RSO ?

The RSO has a compactor for use with 55 gallon barrels. It reduces waste volume by approximately 50%. Dry waste will be compacted by RSO.

Try to reduce the volume of wet solid waste (much more expensive than dry!) by pouring out any liquid from test tubes or vials into bulk liquid waste containers and discarding the tubes and vials into dry waste.

NRC regulations forbid the disposable of radioactive materials (even slightly contaminated items) into the normal trash.

WHAT IS THE BILLING PROCESS ?

The cost to the user depends upon the category (long lived, short lived or low level) and the volume of the waste and not the quantity of radioactivity. The investigator's budget # is charged for the waste disposal.