Radiation exposure risks with

One feature of reprocessing plants which poses potential risks of a different nature from those ia a power plant is the need to handle highly radioactive and fissionable material ia Hquid form. This is necessary to carry out the chemical separations process. The Hquid materials and the equipment with which it comes ia contact need to be surrounded by 1.5—1.8-m thick high density concrete shielding and enclosures to protect the workers both from direct radiation exposure and from inhalation of airborne radioisotopes. Rigid controls must also be provided to assure that an iaadvertent criticahty does not occur. 

Compare the risk of evacuation with that of radiation exposure at TMI-2,... 

The response to a nuclear explosion differs dramatically from the response to an attack with conventional explosives. When conventional explosives such as dirty bombs disperse radiological materials, the health hazards from the radiation exposure are secondary to the explosion (flying shrapnel, debris, fire, and smoke). In the case of a nuclear explosion, the risks of death, serious short-term health effects, and serious long-term health effects are no longer secondary to the explosion. 

Tb a considerable extent, these risk estimates and risk comparisons are merely exposure comparisons. Their interpretation is aided by comparing them with natural background radiation exposure and its variations or comparison to the other risks of a particular activity or to the risks associated with safe industry . 

Table 8.3—Various activities involving radiation exposure, with estimates of the associated risks of cancer mortality...

Additionally, before the first study with radiolabeled test substance in man can be started, a risk assessment of a human radiokinetic study is mandatory. The estimation of the radiation exposure in humans given a radiolabeled dose is based on exposure data obtained typically from QWBA studies in animals. 

Alternatively, a threshold of concern could be assumed for the risk of serious effects, such as cancer and hereditary disease or serious impairment of the intellectual ability (loss of more than 10 IQ points). One option might be that lifetime exposure entails a lifetime risk of 10 in one million of suffering such a serious effect. This is the level of cancer risk associated with the WHO guidelines for drinking water for the sake of comparison, it is about 400 times stricter than the risk for cancer and hereditary disease associated with radiation exposures at the dose limit for the public (ICRP 2008). 

The test is performed according to the Ph.Eur/USP monograph on Sterility tests [13,14], but with an important modification. Small batch sizes, typical for radiopharmaceuticals, make it necessary to use smaller test volumes than required in the monographs. Also the risk for radiation exposure supports this modification. 

When we are concerned about the long-term effects of radiation exposure, it is important to understand how much DNA damage is caused by the radiation, so the quality of the radiation must also be considered. Because of this, we measure radiation dose in units of Sv (or rem) when we are considering, for example, the risk that someone will develop cancer as a result of their radiation exposure. This is why regulations and radiation dosimeter reports use units of Sv or rem they are concerned with protecting us against the risk of developing cancer several decades later in our lives. 

In this chapter, we will follow this convention of using units of Gy and rad when we are concerned about the short-term risk of skin burns, radiation sickness, or fatal radiation injury that results from acute radiation exposure and using units of Sv and rem when we discuss the risk of developing cancer many years or decades after the radiation exposure, or when we are discussing compliance with radiation safety regulations. 

Effective dose was a parameter used to assess biological risk related to radiation exposure, from dual-energy X-ray absorptiometry (DXA). Children are a worst case estimate because they absorb higher doses than adults. With the exception of the hip scans in 1- and 5-year-old children, the effective doses were below the negligible individual dose limit of 1 mrem per year (Thomas et al, 2005). 

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