Excerpt from the OH&S Canada magazine
“An Ontario power station will test additional workers for exposure to low levels of radiation as a precautionary measure,” a spokesman revealed. A memo sent to workers of Bruce Power, and a copy obtained by the Canadian Press, informed employees that due to alpha contamination discovered last year, the company would test other workers.
Last November, (2009) contamination was discovered in the reactor vault where up to 563 people had been working. The company eventually concluded that 195 workers had been exposed and ordered testing. However, as a result of that experience, the company said it will be testing 40 other employees at one of its stations, Bruce A. The memo said the highest probability of exposure to alpha was fuel handling, and the company has started to assess the dose that the workers might have received. Based on the discovery, additional employees will be tested. The spokesperson said the company normally tests for gamma radiation levels in nuclear plants, and it had previously assumed certain amounts of alpha based on those results. “The assumptions, we have learned, were not accurate, and the levels of alpha were higher,” said the spokesperson.
The Canadian Nuclear Safety Commission has been made aware of Bruce Power’s Plan.
Alpha radiation contamination can cause sickness if there are high rates of exposure. “We work with radiation all the time and our employees are very familiar and very aware of the potential hazard.”
End of report from the Canadian Press.
Health Effects on Ionizing Radiation
â— Alpha and beta particles, and X-rays and gamma rays, are forms of ionizing radiation
â— Ionizing radiation has the potential to cause cancer in many body organs
â— Many workers who are regularly exposed to radiation are required by law to wear personal dosimeters to record the cumulative radiation they are exposed to
â— Lifetime dose records for all radiation workers in Canada are maintained by the Federal Department of Health and Welfare
â— Cancer may appear after a latency period of as little as 2 to 4 years in the case of leukemia and 5 to 30 years in the case of most other types of cancers
â— Can also damage the genetic material in the sperm or egg cells, causing mutation, which may be passed down to offspring
â— The radiation dose is determined by the strength of the source, the type of radiation, the length of exposure and the distance from the source. Is measured by an international system of units (SI)
â— The energy absorbed by the body is called the ‘absorbed dose’ and is expressed in units of Gray
â— The ‘dose equivalent’ measurement is called Sievert
â— Example — x-rays penetrate body tissues
â— Health Effects on Ionizing Radiation
â— The greatest effects of ionizing radiation are on cells that are rapidly dividing
â— Example — blood forming system in the bone marrow is easily damaged
â— Example — the embryo-fetus is also vulnerable
In the control of radiation, exposure should be kept as low as possible. It can be controlled at the source by shielding equipment, it can have controls along the path by increasing the distance from the radiation source to the worker, or through the use of radiation barriers, and finally, controls at the worker involve isolating the operator, limiting the exposure and wearing appropriate PPE.
Certified members of any JHSC, who work in places where X-rays or Gamma rays are present, should become thoroughly familiar with the regulations covering their workplace. As well, radiation safety officers are required by law in many of these workplaces. It is my belief that independent contractors should be completing any assessment required during this mini crisis and in my opinion, this must have been the case. If you read between the lines, the first words out of their mouths were, “all received acceptable doses”. The next we hear that they assumed wrong and new testing was ordered. (remember what assume spells) It must have been outside independent contractors, ones with no political agenda. I am a firm believer in independent outside contractors. This is why, in the event of an occupational death, the MOL, the police association with jurisdiction, or the appropriate Federal Commission, nead to head up the investigation, and not one through internal resources.
I guess I should make my position a little clearer. I lost a dear friend a few years ago from cancer. She was only 46 years old, and she was a chemical engineer at Hydro. It was her job to flush the nuclear residue out of the lines when a reactor was shut down for maintenance. Please do not try to convince me that she didn’t receive some sort of radiation that was work-related.
Thank you for reading this blog.
Remember — In Ontario, “ALL Accidents are Preventable”
‘Work’ and ‘Play’ safe.
Daniel L. Beal
CHSEP – Foundation Level
VP & Senior Trainer