Radiation dose limit
Writer: Sterilization Time: 2020-09-02 Browse: 605 ℃
Occupational exposure dose limit
Effective radiation dose limit
The annual average effective radiation dose for 5 consecutive years does not exceed 20msv
The effective radiation dose in any year shall not exceed 50msv
Equivalent radiation dose limit: eye lens: 150msv per year; skin: 500mSv per year.
Public radiation dose limits
Effective radiation dose limit: 1msv per year. 5msv in any 12 months.
Equivalent radiation dose limit: eye lens: 15mSv per year; skin: 50msv per year.
Radiation protection equipment
lead apron, lead collar, half body protective apron.
Health protection standard for industrial X-ray flaw detection
The main performance of the instrument is as follows
a) The minimum range is 0 ~ 10 μ Gy · H-1;
b) Energy response 30 ~ 500kev ± 30%
c) The response time of reading is less than 15s.
The area where the air kerma rate is above 40 μ Gy · H-1 is defined as the control area, and the area with the air kerma rate above 40 μ Gy · H-1 outside the boundary of the control area is designated as the management area.
Generally, the following points should be monitored around the industrial X-ray flaw detection equipment
a) The location of abnormally high radiation level was found through patrol survey;
b) 5 cm outside the door of the flaw detection room, 1 m above the ground, 3 points on the left, middle and right side of the door are measured;
c) At least two points shall be measured on each wall at 5cm away from the ground and 1m away from the wall of flaw detection room or adjacent wall
d) The radiation level at the residence side of non radiation workers around the flaw detection room should not be greater than 2.5 μ Gy · H-1. The radiation level on the resident side of radiation workers should not be greater than 2.5 μ Gy · H-1.
Industrial cobalt-60 radiation source is a kind of radiation source
Industrial cobalt-60 radiation source is a kind of radiation source, which is extremely radioactive and dangerous. If a person is exposed to the naked source, his life will be in danger immediately. Because of this, we have never been careless about the safety work. We not only require ourselves to do a good job, but also closely cooperate with the carrier and irradiation station.
Co-60 gamma rays used in irradiation processing
In fact, the energy of Co-60 gamma rays used in irradiation processing of products is only 1.17mev and 1.33mev, The average energy is 1.25 MeV. The research shows that the main elements C (carbon), O (oxygen), n (nitrogen), P (phosphorus) and S (sulfur) can be converted into radionuclides at least by more than 10 MeV of high-energy radiation, and the ability of Co-60 gamma ray is far lower than the energy threshold value that may induce radioactivity in the product, and the induced occurrence nuclides and their compounds will not be produced.
The joint expert committee of FAO, IAEA and who concluded that when the total average irradiation dose of any commercial food reaches 10 kGy, there is no toxicological hazard, and the food treated in this way does not need toxicological examination. Food irradiated with 10 kGy dose does not cause special nutritional or microbiological problems.
Treatment of three wastes
X-ray external radiation is mainly produced in the working process of the x-ray device. In addition, shielding materials can be used to shield the radiation. Due to the low energy of X-ray, no induced radioactive substances will be produced in the working process, so the treatment of radioactive "three wastes" is not considered; a small amount of ozone and nitrogen oxides will be produced in the working process, and the ventilation fan can be used for ventilation.