If dosimeters are not returned by the tenth of the month, analysis of the dosimeters will be delayed. The RSO may request more frequent exchanges for high-dose experiments or work, or if a worker is approaching a limiting dose. If your dosimeter is not returned, it becomes an ineffective tool for dose monitoring. We are required by the Center's radioactive materials license to have a working dosimetry program, and unreturned dosimeters place our permission to use radioactive material at risk.
All dosimetry reports are reviewed upon receipt by the RSO. Investigations may include visiting the lab and requesting an explanation from the person about the exposure. Records of these investigations are presented to the RSC. Annual dose reports are available for each individual monitored that year and will be sent to all workers who are required to be monitored per WAC A worker may request his or her dose and dose history at any time by contacting the RSO.
Some areas which receive exposure to radiation are monitored continuously with a dosimeter to be sure no excessive levels occur.
This is for tracking purposes or to determine regulatory compliance for public dose limits. If you would like an area monitored with a dosimeter, contact the RSO. Radiation protection regulations specify a lower dose limit for women who formally declare their pregnancy to reduce the risk to the developing embryo or fetus see Table Female workers occupationally exposed to radiation who become pregnant may declare their pregnancy to take advantage of the lower dose limit, additional monitoring and counseling.
Declaration of pregnancy is voluntary. The lower dose limit does not apply if the pregnancy is not formally declared in writing, although counseling is always available from the RSO. The pregnancy may be undeclared at any time. Declaration of pregnancy must be in writing and include the estimated date month and year of conception.
The RSO will review the worker's previous radiation exposure, order a fetal monitoring dosimeter and suggest ALARA techniques, provide counseling or additional information as requested. The worker should schedule an appointment with the RSO after the declaration of pregnancy.
The RSO will review and provide radiation protection guidelines during the appointment. Declared pregnant radiation workers are issued a fetal monitoring dosimeter. The fetal monitoring dosimeter maybel be used to evaluate the worker's monthly dose and will be exchanged monthly. The worker's regular whole body dosimeter, and ring dosimeter s if applicable will remain on a quarterly exchange cycle and will be used as the dose of record. When working with radioactive iodines I, I, and I, there is a chance the iodine may enter the body via inhalation, ingestion, or absorption through the skin.
The effective half-lives in the thyroid gland for iodines are 40 days for I, eight days for I, and 13 hours for I. The iodine that does not become incorporated in the thyroid is eliminated from the body, usually within three days.
The dose limit for the thyroid dose equivalent is 50 rem per year. Note that the thyroid gland varies in activity, shape, and size; therefore this is only an estimate for an average thyroid.
The RSO performs thyroid bioassays routinely to verify that proper safety precautions are taken by those in the thyroid bioassay program, and that those who work with radioiodines do not receive unmonitored doses. Everyone in the thyroid bioassay program should have a baseline bioassay before beginning work with radioiodine and upon termination of work with radioiodine or of employment.
As part of the RMUA process, workers who are required to have bioassays are identified. Workers may perform bioassay screenings on themselves on a frequent, routine basis. Noticeable activity twice above background levels in the thyroid should be brought to the attention of the RSO for further evaluation.
The investigation attempts to find the cause of the burden and to identify methods of prevention. This dose is added to the annual dose report for that individual. Workers may perform their own self-screening thyroid bioassays by using the following procedure.
Any questions should be addressed to the RSO or the radiation safety staff. Any self-screening that indicates greater than 8 nCi for I, 10 nCi for I, or two times background should be reported to the RSO for further evaluation. Radioactive hydrogen, usually called tritium or 3 H, is a low energy The farthest this beta particle can travel in air is only 4.
Since the beta particle is unable to penetrate the outer dead layer of skin, working with millicurie quantities of tritium does not pose an external radiation hazard. However, when tritiated compounds are ingested, injected, inhaled or absorbed through the skin, they mix with water in the body and permeate all tissue within a few hours, irradiating the body internally in a fairly uniform manner.
In water, the beta particle from tritium only travels six microns, but the diameter of a cell nucleus may be on the order of eight microns. Therefore, when tritium releases the beta particle while in the nucleus of a cell, almost all of the energy is deposited in the cell and could lead to damage.
The majority of tritium used is labeled to organic compounds. When tritiated organic compounds are ingested, the majority is catabolized broken down in the gastrointestinal tract and tritiated water is produced.
The tritiated water is then dispersed throughout the body. Injection, inhalation, or absorption through the skin of tritiated organic compounds results in less of the compound being broken down to tritiated water. Currently, utility, industrial, medical, government, and academic organizations use and dispose of radioactive materials. Because radiation is known to cause cancer, it is prudent to monitor the environment for radioactivity.
Minnesota has maintained a radioactivity monitoring program since , when measurements of radionuclides were initiated in response to atmospheric testing of nuclear weapons. The program was expanded to include monitoring around nuclear generating facilities: Elk River plant, ; Monticello plant, ; and Prairie Island plant, The Elk River reactor was decommissioned in Environmental radiation monitoring is the systematic collectionand analysis of certain environmental media, such as air, milk, and water, to determine the level of radioactivity present.
Levels of radioactivity are compared to safety standards to ensure a safe environment. The current Minnesota Department of Health's environmental radiation monitoring program objectives are:. These objectives are met by sampling various environmental pathways for human exposure and directly measuring radiation levels near the plants and at other locations around the state. Natural radioactivity originates from radioactive elements in the earth's crust as well as extraterrestrial sources, such as cosmic rays.
The normal level of natural radiation in Minnesota ranges from to millirem each year. As a rough approximation, the average is about one millirem per day. Most of our natural exposure is due to radon, a gas which emanates from the earth's crust and is present in the air we breathe. Environmental monitoring is conducted near the Monticello and Prairie Island nuclear generating plants. Monitoring includes the collection and analysis of air, water and milk. No unsafe levels of radioactivity or direct radiation have been detected near the Monticello and Prairie Island nuclear generating plants in Minnesota.
Environmental Radiation Monitoring FAQs In the s and s, atmospheric testing of nuclear weapons introduced large amounts of radioactivity into the global environment. Does Minnesota have an environmental radiation monitoring program?
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