NR_37_IOE_EN_117-185_MOD_4.pdf

Transcript

1. Medical exposures of patients must be justified by weighing the diagnostic or therapeutic benefits they may produce against the corresponding detriment, taking into account the risks and benefits of available alternative techniques that do not involve exposure.
2. Normal exposure of individuals must be restricted in such a way that neither the effective dose nor the equivalent dose in the organs or tissues of interest, caused by the possible combination of exposures arising from authorized practices, exceeds the dose limit specified in the following table, except in special circumstances, authorized by CNEN.
4. Sources of ionizing radiation, radioactive material storage sites and workplaces with exposure to ionizing radiation, whether industrial or naturally occurring, must be marked with the international symbol (trefoil) and the supplementary warning, recommended by the International Atomic Energy Agency - IAEA, as per Annex II of NR- 37.
6. When it is not possible to use methods that do not use radioactive sources, the installation operator must justify and document the decision in a report prepared by a legally qualified professional, recorded in the PGR.
7. Priorities of other standards Compliance with the requirements of this NR and NR- 34 does not exempt compliance with other provisions established by the standards of the National Nuclear Energy Commission - CNEN, or, in the absence thereof, the provisions set forth in national and international technical standards and regulations, in that order. The facility operator must ensure that contracted companies that handle or use equipment with radioactive sources are licensed by CNEN.
8. General measures For the operator: The facility operator must ensure service by Radioprotection Service - SR, including for naturally occurring radioactive material, in accordance with CNEN standards.
9. Information The SR must establish and have adequate and sufficient personnel, facilities, procedures and equipment to perform all tasks safely, as well as provide assistance in the event of an accident or emergency.
10. Supervisor The facility operator must appoint a Radiological Protection Supervisor - SPR, responsible for supervising work involving exposure to ionizing radiation.
11. CNEN The SPR must have a valid qualification certification in the area of ​ ​ activity, according to its activity and in accordance with CNEN standards.
12. The doctor responsible for the PCMSO must keep the record of each worker exposed to ionizing radiation updated, in accordance with the CNEN NN 3.01 standard and other CNEN standards.
13. Workers exposed to radiation above the limits established by CNEN standards must be removed from activities involving radiation exposure and evaluated in accordance with the PCMSO. The return of the absent worker to work involving ionizing radiation will depend on authorization from the examining physician who is a specialist in this area, through a record in the employee's ASO. Before starting work involving a radioactive source or material, the facility operator must require copies of the ASOs concerning its workers from the contractor. Before accessing supervised and controlled areas, workers must be formally authorized by the SR. The facility operator must ensure that workers exposed to ionizing radiation are trained in accordance with CNEN standards and under the responsibility of the SR.
15. The operator and the medical team The facility operator must provide a medical service specialized in the type and proportions of radioactive sources and materials present, in order to ensure medical supervision for workers exposed to ionizing radiation and appropriate treatment for those involved in accidents. Specialized medical service The specialized medical service may be provided by a legally qualified professional with proficiency in the subject or by a specialized company hired, as long as they are under the coordination of the doctor responsible for the PCMSO.
16. The installation operator must ensure the preparation and implementation of the Radiation Protection Plan - PR approved by CNEN, under the technical responsibility of the SPR duly certified by CNEN. The PR must also include: be unique to each platform; be coordinated with the PGR of the facility operator and service providers whose outsourced workers are exposed to radiation; be considered in the preparation and implementation of the PCMSO; be presented to the CIPLAT of the installation operator and outsourced companies, where applicable, with a copy attached to the minutes of that committee; be considered in the platform's Emergency Response Plan - PRE, described in chapter 37.28 of this NR; be kept up to date.
17. After the occurrence of exposures resulting from emergencies or accidents, or suspected occurrence of accidents, the facility operator must ensure that measures are taken for the immediate evaluation of workers, according to CNEN standards.
18. In order to verify its suitability and effectiveness in controlling exposure to ionizing radiation, with a view to making the necessary adjustments and establishing new goals and priorities, the PR must be evaluated: annually; when reviewing the PGR; whenever an accident occurs, emergency situations occur or illness is detected due to exposure to ionizing radiation.
19. It is forbidden to smoke, rest, eat, drink, apply cosmetics, store food, drinks and personal belongings in places where they are handled, transported, stored or where there is a risk of contamination by radioactive materials. The facility operator must ensure the hygiene and maintenance of clothing and other PPE used in activities with radioactive materials, as well as their decontamination or immediate replacement when damaged or lost. Immediately after the end of the service or after stopping for meals, the facility operator must ensure an appropriate place to change work clothes for clean ones, according to CNEN standards.
21. Services and operations with industrial radioactive sources Before starting the execution of services and operations involving ionizing radiation, the facility operator must prepare the specific PR, which, in addition to what is foreseen in the needs discussed previously in the course, must contain at least: the characteristics of the radioactive source; the characteristics of the equipment; the list of workers involved; calculation memories of physical isolation distances in open installations; the handling and storage method of the radioactive source on board; the procedures, equipment and accessories to be used in accident or emergency situations.
22. In the case of industrial operations with radioactive sources, the specific PR may be prepared by the service provider in accordance with CNEN standards, with the facility operator being responsible for ensuring compliance. NO. 37 The operator of the facility and the company responsible for services and operations involving ionizing radiation must adopt the following measures:
23. Assessment of the safety and reliability of structures and equipment associated with the radiation source; Assessment of the location, classification and signage of supervised, controlled and physically isolated areas; Installation of adequate physical means to delimit supervised and controlled areas, preventing access by unauthorized workers; Definition of alarms in the Emergency Response Plan - PRE; Identification and signage of circulation, entry and exit routes and escape routes within supervised and controlled areas; Adequate and emergency lighting in supervised areas, controlled areas and on circulation routes where services and operations involving ionizing radiation are being carried out; Signaling and physical isolation of locations intended for radioactive sources and waste.
24. In addition to the measures prescribed in the PR, during exposure to radioactive sources, the following measures must be adopted: Exposure of the smallest possible number of workers to carry out the activity; 1. Execution of the service in accordance with the instructions of the work permit; 2. Tasks may only be performed by authorized Occupationally Exposed Individuals - IOE; 3. immediate interruption of service in the event of a change in conditions that makes it potentially dangerous, in accordance with NR 37. 4. immediate interruption of activity and removal of the source for exposures above the limit established by Annex No. 5 (Ionizing Radiation) of NR-15 (Unhealthy Activities and Operations); 5. decontamination, reassessment and resizing of the area and exposure time, before restarting the activity, if the situation mentioned in the option above occurs. 6.
25. Upon completion of the service, the SR must: collect, package and store the source safely, in a segregated, locked, demarcated, signposted location, with low circulation of people and monitored for the levels of radiation emitted; assess the radiation level in the area where the service was performed, in accordance with the PR; proceed with the release of supervised and controlled areas, removing isolation and signage.
26. Upon completion of the service, the SR must: collect, package and store the source safely, in a segregated, locked, demarcated, signposted location, with low circulation of people and monitored for the levels of radiation emitted; assess the radiation level in the area where the service was performed, in accordance with the PR; proceed with the release of supervised and controlled areas, removing isolation and signage.
27. Naturally occurring radioactive materials (NORM) The contract operator must ensure that the facility operator carries out an assessment of the presence of naturally occurring radioactive materials in the work environment that may pose risks to the health of workers, in accordance with CNEN standards. The facility operator must identify the operations and locations where radiation exposure or incorporation may occur, the trajectories of the radioactive material and its means of propagation, and adopt the preventive measures prescribed in CNEN standards.
29. A monitoring plan defined by the SPR must be drawn up, the frequency of which must meet, at a minimum, the review of the PGR. Monitoring should be carried out in places where naturally occurring radioactive materials are present, especially in:
30. NORM When opening equipment, pipes, accessories and other elements of the unit, preventive measures guided by the SPR must be adopted, considering the possibility of the presence of naturally occurring radioactive materials. The removed waste must be characterized in accordance with CNEN standards. 1. Based on the analysis of the radioactive material, the facility operator must identify the types of radiation and their potential harm to humans, as well as measures to ensure the safety and health of workers exposed to ionizing radiation. 2. If collective protection and operational and administrative measures do not reduce exposure levels and incorporation to the dose values ​ ​ provided for in CNEN standards, the facility operator must reassess the platform design and implement engineering solutions to ensure compliance. 3. The facility operator must ensure that service providers carrying out cleaning activities at sites where naturally occurring radioactive materials may be present comply with CNEN standards. 4.
31. NORM When opening equipment, pipes, accessories and other elements of the unit, preventive measures guided by the SPR must be adopted, considering the possibility of the presence of naturally occurring radioactive materials. The removed waste must be characterized in accordance with CNEN standards. 1. Based on the analysis of the radioactive material, the facility operator must identify the types of radiation and their potential harm to humans, as well as measures to ensure the safety and health of workers exposed to ionizing radiation. 2. If collective protection and operational and administrative measures do not reduce exposure levels and incorporation to the dose values ​ ​ provided for in CNEN standards, the facility operator must reassess the platform design and implement engineering solutions to ensure compliance. 3. The facility operator must ensure that service providers carrying out cleaning activities at sites where naturally occurring radioactive materials may be present comply with CNEN standards. 4.
32. Radiation protection reports are an integral part of the platform's PGR and must be discussed at the CIPLAT meetings of the installation operator and service providers, with copies attached to their minutes.
33. The facility operator must implement procedures to prevent exposure and passive contamination of workers not involved in activities with naturally occurring radioactive material. Additional measures to those mentioned above must be implemented to control the risk of contamination of water, food and air conditioning by naturally occurring radioactive materials, when recognized in the PGR, in accordance with NR-09.
34. Specific areas for the decontamination of workers must be established by the SR, in accordance with specific CNEN legislation, national or international technical standards, in that order.
35. Workers are prohibited from entering houses with contaminated clothing, PPE and work equipment. If internal contamination by naturally occurring radioactive material is found, the platform's PCMSO must include blood and excreta analyses and, if necessary, a full-body counter examination to be carried out by institutions authorized by CNEN.
36. RADIOLOGICAL INCIDENTS AND ACCIDENTS INTRODUCTION Despite the increasing use of nuclear energy for peaceful purposes, both in the generation of electrical energy and in medicine, industry, agriculture and research, the acceptance of nuclear technology continues to encounter resistance within society, due to the fear of nuclear or radiological accidents. Accidents caused by technical failure have a very low probability of occurring, given the reliability of equipment and safety systems used in the nuclear sector. However, practice has shown that most serious accidents, such as those in Chernobyl and Goiânia, are caused by procedural failure, i.e. human error.
37. To this end, events are classified into 7 levels, as illustrated below. The lowest levels (1 – 3), called incidents, are nuclear occurrences restricted to the Installation area and which did not affect the external area. The highest levels (4 – 7), called accidents, reflect events whose nuclear impact reached the external area of ​ ​ the Installation. Events that have no significance from a safety point of view, classified as level 0 or below the Scale, are called deviations and may indicate the degradation of some protective barriers.
38. International Nuclear Event Scale (INES) for Prompt Communication of the Safety Significance of Events at Nuclear Facilities
39. Details of the Safety Criteria or Attributes Adopted for Classifying Events on the International Nuclear Event Scale
40. The Chernobyl and Goiânia Accidents The Chernobyl Accident
41. Of the 600 workers present at the time of the accident, 134 received high doses of radiation (0.7-13.4 Gy), with 30 workers and firefighters dying in the first few weeks after the accident; During 1986 and 1987, 200,000 people involved in decontamination work received doses between 0.01 Gy and 0.5 Gy and still require medical monitoring today; About 116,000 people were evacuated in 1986, and after that another 220,000 from neighboring regions were transferred to other locations; The incidence of thyroid cancer in individuals who were exposed as children (around 1800), particularly those from severely contaminated areas, was found to be considerably higher than expected before the accident; After 17 years, it was not possible to determine the percentage increase in the population of cancer and other diseases associated with ionizing radiation resulting from this accidental exposure of individuals. VICTIMS
42. Release into the atmosphere of a quantity of radiation equivalent to that from 500 atomic bombs of the size of the one dropped on the Japanese city of Hiroshima; Isolation of an area around Chernobyl, maintained to the present, with a radius of 30km, called the “Exclusion Zone”; Soil and water contamination in numerous European countries; In the five years following the accident, the concentration of radioactivity in plants, fish and water decreased by 90%. However, in the 1990s, contamination decreased very little and still remains high, according to measurements taken in England and Norway. ENVIRONMENTAL IMPACT
43. ECONOMIC IMPACT
44. THE GOIANIA ACCIDENT
45. 249 people (out of 112,800 monitored by CNEN) presented radiation levels above normal for the region; 20 people were hospitalized (one of them had their right forearm amputated); 4 dead in the first 2 months after the accident and another 3 dead a few years later. VICTIMS
46. 50 domestic animals sacrificed; Contamination of plants, vegetables, herbs, roots and fruits within a radius of approximately 50 meters of the main sources of contamination. Trees were uprooted and a large amount of highly contaminated soil was excavated and replaced with “clean soil”; Contamination by Cs-137, through the rainwater and sewage systems, of sections of the rivers, streams and creeks located in the vicinity of the contaminated areas. Fortunately, the water supplying the region was not affected; Around 1,700 tons of radioactive waste (packaged in containers and drums) were generated as a result of the accident, having been temporarily stored and, around ten years later, deposited in a repository built in Abadia de Goiás, 20 km from Goiânia. ENVIRONMENTAL IMPACT
47. Several products originating from the State of Goiás were rejected in other States; The export of Brazilian products was harmed; The construction and control of the Abadia de Goiás deposit cost the country around 15 million dollars; Victims of the accident have been receiving financial assistance from the government. ECONOMIC IMPACT
48. In any type of accident, saving lives, fighting the fire, isolating the area and notifying the Competent Authorities are priority actions to be taken promptly. In general, the following measures should be taken in the initial, intermediate and final phases of a radiological accident, as applicable. PHASES OF AN ACCIDENT INVOLVING RADIOACTIVE MATERIAL
49. The initial phase of an accident response includes first aid actions and an initial assessment of the severity of the event, including the characteristics of each radioactive source involved, in order to guide the measures to be taken to regain control of the situation, namely: Rescue and medical assistance to victims; Control of fire and water used in fighting fires; Establishment of a communication channel between the accident site and the Competent Authorities; Monitoring of irradiation and contamination levels; Isolation of affected areas; Preliminary evaluation of the event. INITIAL PHASE
50. The control phase begins when data is available on each radionuclide involved in the event and on the radiometric survey carried out on site, thus enabling decision-making to control the radiological emergency situation, highlighting: Control access to the accident site; Use of personal protective equipment and establishment of safety procedures for personnel involved in rescue and decontamination work; Shelter and evacuation; Personnel decontamination; Initial decontamination of areas; Food and water control. INTERMEDIATE OR CONTROL PHASE
51. Once the radioactive source is under control and after implementing measures to protect workers, the general public and the environment, the Competent Authority must declare the end of the emergency phase, using the available communication channels (newspaper, radio, television). In this phase, the final decontamination and restoration work of the affected areas, management of the radioactive waste generated, as well as medical monitoring of the victims and sending of dosimeters for reading must be continued. It is important to emphasize that IOEs exposed to radiation in an emergency situation must monitor radiation levels using radiation meters or BIP-type electronic equipment so that they do not reach regulatory limits. FINAL OR POST- EMERGENCY PHASE OR, ALSO, RECOVERY PHASE
52. EMERGENCY PLAN
53. In addition to the procedures that must be adopted by users of ionizing radiation sources to prevent, as far as possible, the occurrence of incidents and accidents, plans for action in emergency situations must be drawn up in order to limit the consequences of any abnormal occurrence, incident or accident that can be foreseen as far as possible. PROCEDURES
54. The content, characteristics and scope of emergency plans should be established based on the results of an analysis of probable accidents, taking into account lessons learned from operational experience and accidents that have occurred with similar radiation sources. CONTENT
55. Therefore, the Emergency Plan must include, in addition to the types of admissible accidents, including their detection system, the topics covered below, as appropriate. PLAN AND EVENTUALITY The Emergency Plan must demonstrate that, in the event of an incident or accident involving ionizing radiation, appropriate measures will be taken to ensure the health and safety of the public.
56. The responsibilities of each individual and organization involved in the process of responding to a radiological incident or accident must be very well established, in particular the authorities and the hierarchy to be respected, in order to enable harmonious management of the intervention process. Furthermore, the people designated to act in incidents/accidents must be adequately trained and familiar with their specific tasks. To this end, the procedures contained in the Plans must be rehearsed through periodic accident simulation exercises, and it is important that other people and authorities whose assistance may be needed in the event of a real accident participate in these simulations. RESPONSIBILITIES AND PROCEDURES FOR NOTIFICATION TO COMPETENT AUTHORITIES AND COMMUNICATION WITH THE PUBLIC
57. Prompt notification of an accident to the competent authorities is extremely important in order to limit its consequences, and instructions to be followed for communication with bodies that can provide immediate assistance (Fire Department, Hospitals, Police, etc.) must be easily accessible. RESPONSIBILITIES AND PROCEDURES FOR NOTIFICATION TO COMPETENT AUTHORITIES AND COMMUNICATION WITH THE PUBLIC
58. In this context, the National Nuclear Energy Commission, CNEN, has a structure set up to investigate radiological events, and can provide data to guide the local team involved and send specialists to assess the magnitude of the event or, if necessary, trigger its emergency response system. RESPONSIBILITIES AND PROCEDURES FOR NOTIFICATION TO COMPETENT AUTHORITIES AND COMMUNICATION WITH THE PUBLIC
59. From a communication point of view, it is extremely important and mandatory that in any emergency situation or situation that deviates from normality, CNEN is contacted immediately. RESPONSIBILITIES AND PROCEDURES FOR NOTIFICATION TO COMPETENT AUTHORITIES AND COMMUNICATION WITH THE PUBLIC
60. Levels of Intervention and Action for Immediate Protection. When the increase in dose resulting from a procedure adopted without protective action may lead to the exposure of individuals, over a given period of time, to levels of radiation that may cause serious damage, the intervention is fully justified and aims to reduce or even avoid this exposure. RESPONSIBILITIES AND PROCEDURES FOR NOTIFICATION TO COMPETENT AUTHORITIES AND COMMUNICATION WITH THE PUBLIC
61. The International Atomic Energy Agency, IAEA, based on general principles that govern the selection of intervention levels for radiological emergencies recommended internationally, suggests some values ​ ​ of intervention levels for taking urgent protective actions, as follows.
63. Isolating the area where an incident or accident has occurred is usually the first step to be taken to prevent laypeople from accessing the site, protecting the public from possible external radiation, inhalation of airborne radionuclides and inadvertent ingestion of radioactive material resulting from contact with contaminated surfaces. Area Isolation, Shielding, Evacuation
64. The possibility of shielding a radioactive source that is out of control should be considered by the technical personnel involved in the rescue. A simple example of how to regain control of a source is to use lead containers to store radioactive material that has lost its shielding. Sealed sources can also be immersed in a bucket of water or sand to reduce exposure rates. In the case of small contaminated areas, blankets, plastic or other suitable materials can be used to cover the affected area and prevent dispersion. THE POSSIBILITY OF PROVIDING SHIELDING FOR THE RADIOACTIVE SOURCE
65. When the dispersion of radioactive material is significant, the decision to evacuate people must be taken by the Competent Authority, taking into account the technical opinions of professionals in the nuclear sector. THE POSSIBILITY OF PROVIDING SHIELDING FOR THE RADIOACTIVE SOURCE
66. Decontamination of people suspected of contamination should initially be done immediately, by removing clothing and bathing them with plenty of water, and then seeking specialized medical assistance. Contaminated clothing and other materials should be collected for later decontamination or treatment as radioactive waste. DECONTAMINATION OF PERSONNEL AND AREAS
67. Establishing controls on food and water intake is also essential to prevent the spread of radioactive contamination in living beings. DECONTAMINATION OF PERSONNEL AND AREAS
68. The table below presents a summary of the methods used for decontamination of personnel. Decontamination should begin with the first method listed, i.e. the simplest, and, if necessary, continue using the others, listed in increasing order of severity.
69. Event report Any event that may expose the public or workers to radiation levels that result in doses higher than the respective primary limits established by CNEN must be notified to that Competent Authority, as a matter of urgency, and recorded in a specific book, on the same day of the occurrence, and all communications and reports must be kept on file, together with the results of the investigations carried out. Reports of abnormal occurrences must be evaluated by the Competent Authority with the aim of extracting lessons from the incident and introducing improvements in the area of ​ ​ security. The detailed situation report must contain, where applicable, at least the following information: