Radiation By FF Mason

1. Radiation By FF Mason

2. Incidents involving radiation are rare. However, due to the quantities of radioactive materials now used in industry and medicine there is the potential for an incident. Firefighters must train to deal with such an event. Firefighters must have knowledge of; • The risks involved • Protective measures. • Measuring apparatus required • Some radioactive materials are to varying degrees flammable or combustible and to this extent carry a fire hazard. This hazard is, however, no greater because of radioactive properties.

3. Types of Radiation There are 3 main Types of radiation; Alpha Emitted in large particles Have a short range Stopped easily Beta Smaller particles than Alpha Have a range of between 1-2 metres Stopped by thin plastic or metal Gamma Pure electromagnetic radiation Can travel large distances Only stopped by a large material (Lead)

4. Radiation is not detectable by any of the senses Measurable biological damage can be delayed for long periods Radiation cannot be destroyed, but its intensity will diminish according to the half-life of the isotope emitting the radiation. The trunk of the body contains vital organs and has more need of protection from gamma radiation Clothing/protective suits will not protect from gamma radiation There are no inherent fire hazards associated with radioactive materials in general Radiation may originate from: Sealed sources, where mainly an external hazard from gamma radiation exists. Unsealed or open sources, where in addition to the external hazard, the possibility of further hazards exists since contact could result in contamination. Features of a Radiation Hazard

5. The dosimeters used by the Brigade measure gamma radiation only. They are calibrated in milliSieverts per hour (mSv/h) Male Firefighters; 15 mSv in any one incident, or 13 week period 20 mSv per year In certain special circumstances a maximum of 50 mSv in any one incident Female Firefighters; 13 mSv in any 13 week period – (intake must be received uniformly throughout the period to protect reproductive cells) Upon declaration of pregnancy, female firefighters are to be removed from operational duties Maximum external dose

6. The effects of radiation on the human body depend on whether the source of the radiation is inside or outside the body. These are referred to as the 'internal' and 'external' hazards. Other factors affecting the degree of biological damage to the body are The size of the absorbed dose. The period over which the dose is received. The type of radiation. The sensitivity of the tissues receiving the dose. The age of the person. Proportion of the body exposed to radiation. The effects of radiation are documented in the Home Office T/B 2/1993. An example of acute whole body exposure to gamma radiation of 3 to 6 sieverts equivalent dose, is sickness and death in 4 to 6 weeks. Biological Effects of Radiation

7. Before entering the risk area, a dosemeter reading should be taken and recorded on the rear of the BA tally At an incident the B.A.E.C.O. is initially responsible for accurately recording the entry/exit dosimeter reading of personnel exposed to radiation. The Officer-in-Charge should be informed of any reading increase. This information is to be recorded on a FB10 Medical information form and FB10a Exposure to Hazardous Materials The O-I-C shall make arrangement for survey and contamination meter readings to be recorded as directed by the Radiation Protection Advisor (RPA), Hazmats officer or site radiation specialist. Recording Exposer to Radiation

8. Radiation presents either an 'internal' or 'external' hazard. At an incident involving radioactive material, it is important to protect the body from as much 'external' radiation as possible. It is particularly important when radioactive vapours, liquids and powders are involved, to prevent the 'external' hazard from entering the body and becoming an 'internal' hazard.

9. Apply the principle of TIME - DISTANCE - SHIELDING Limit Exposure Time to a minimum By limiting the time exposed to a radiation source to reduce absorption levels Keep as far away as practical from the radioactive source Shield the body from the source whenever possible Protection against “external” Radiation

10. Distance, The intensity of radiation is proportional to the inverse square of the distance travelled, If the distance is doubled the received dose is one quarter. Max Dose 1/4 Dose 1/16 Dose Shielding, Radiation will penetrate different materials to varying extents Use of shielding will reduce absorption levels

11. Wear breathing apparatus (BA) and chemical protection suits (CPS) Radioactive material may be in gas, liquid or powder form and may cover a wide area (e.g. at an RTA). Precautions must be taken to prevent the inhalation, ingestion or absorption of radioactive material. DO NOT eat drink or smoke Personnel and their equipment must be comprehensively monitored for contamination using the appropriate contamination meter before they are disrobed and or decontaminated, and are allowed to leave the 'Restricted area' and before they are allowed to eat, drink or smoke. Withdraw if you sustain open wounds Radioactive material may enter the body through open wounds and reach vital organs of the body via the bloodstream. Protection against “internal” Radiation

12. Quartz-Fibre Dosemeter Construction There are 3 main parts, which are all housed in a Tubular Aluminium Body; An Ionisation Chamber (This contains a Quartz Fibre Electroscope) The Charging End A Microscope For operational use the Dosimeter is calibrated to 0 – 50 mSv Use Read by looking through the eye piece Should be held horizontally for an accurate reading Should be worn somewhere easily accessible Testing Inspected weekly and after use Inspected to ensure that the fibre and scale calibrations are not blurred or misted When reading reaches 10 mSv, it should be reset to zero using the charging unit Unit is calibrated annually by a specialist contractor Radiation Equipment

13. Survey Meter RDS 110 The RDS 110 Survey Meter carried on Operational Support Units. It only detects gamma radiation It indicates the dose rate (the intensity of the radiation) at a given point in millisieverts per hour (mSv/h) It also has the facility to read in microsievert per hour (Sv/h) Use Initially the survey meter may be used to establish the outer limits of any "Restricted Area" at an incident involving radiation. Subsequently the BA team leader will carry the survey meter in order to identify the safest protected route to the source To detect a increase in radiation, direct the survey meter (buzzer on) to all sides of the crew as they move. Listening for any increase in the frequency of the 'bleeps' from the instrument Testing Radiation survey meters are to be inspected, and the battery condition checked weekly, and after use. An annual calibration test shall be carried out by specialist contractors

14. Electra Portable Contamination Meter The object of contamination monitoring is to ensure that all personnel and equipment are free from contamination by radioactive material when they leave the restricted area. Carried on all O.S.U. It is easily held Has a single display, Picks up alpha and beta contamination Uses 3 x C Batteries It has an audible indication of counts detected. With a specific high-pitchedtone indicating the presence of alpha radiation Use Connect probe to meter with flexi lead and insert batteries Switch on and set to detect alpha and beta Person using meter dresses in full PPE, Person being checked remains in restricted area Probe needs to be within 2-3cms of item being checked, with care being taken not to contaminate probe. If clothing/equipment is contaminated, place in a doubled heavy duty bag and leave in contaminated storage area within restricted area

15. Testing Test carried out in accordance with PIT note 48 Contamination meters shall be inspected and the battery condition checked weekly, and after use An annual calibration test shall be carried out by specialist contractors

16. Siemens EPD (Electronic Personal Dosemeters) • The EPD are carried on the IRU, and stored in the off mode. • They measure any external dose received from beta or gamma radiation. But this does not include doses to the extremities or internal. • EPDs can provide operational personnel with a early warning of the presence of radiation • It is possible radioactive material could be placed deliberately or otherwise at any incident. • EPD’s should therefore be used when responding to; • Incidents involving radiation • Incidents suspected of of involving radiation • Incidents involving known radiation hazards • Incidents involving explosions • On the instruction of the Incident Commander • Allocation • All new dimension IRU will carry 2 boxes containing 50 each.

17. Any Questions?