Welding is an important part of the maintenance work of thermal power plants, especially the maintenance of high-parameter, large-capacity generator sets, where the importance of welding work is even more prominent. Welding production workers often come into contact with various flammable and explosive gases, pressure vessels and electrical equipment. During the welding process, there are also harmful gases, dust, arc radiation, high-frequency electromagnetic fields, noise and radiation, which are harmful to the human body and the environment. Therefore, even a slight oversight can lead to equipment and personal accidents such as explosions, fires, burns, and electric shocks. Welders are also prone to occupational diseases such as poisoning, pneumoconiosis, blood diseases, photokeratitis and skin diseases. Therefore, welding safety and occupational health should be given considerable attention. [b]1 Safety and health characteristics of commonly used welding methods in thermal power plants[/b] (1) Manual arc welding: Electric welding holes often occur. Welding fumes are the main harmful factor, which can cause respiratory diseases or manganese poisoning. The risk of electric shock is also very high. (2) Argon arc welding: The intensity of arc radiation is greater than that of manual arc welding. Strong ultraviolet radiation can cause skin diseases such as erythema and small blisters. There are high-frequency electromagnetic radiation and radioactive hazards. Toxic gases ozone and nitrogen oxides can cause respiratory diseases. There is also a risk of electric shock. (3) Gas welding and gas cutting: Fire and explosion are the main dangers. When welding non-ferrous metals such as copper and aluminum, toxic gases can cause acute poisoning. (4) Carbon arc gouging: High concentration of fumes is the main harmful factor. It can cause respiratory diseases or poisoning. Sparks may fly during operation, which may cause burns or fires. (5) Plasma cutting: The concentration of arc radiation, ozone and nitrogen oxides is higher than that of argon arc welding. There are also harmful factors such as noise, high-frequency electromagnetic fields, heat radiation and radioactivity. The working conditions are poor and there is a risk of electric shock. [b]2 Examples of welding production accidents[/b] The following are examples of welding accidents that have occurred in the company. 2.1 Burns and Scalds Accidents Minor burns and scalds are very common during maintenance work, mainly due to inadequate personal protective measures, such as failure to wear protective clothing and shoes. Because sparks and molten iron splashes are unavoidable during welding and cutting, ordinary work clothes are ineffective in providing safety protection, resulting in a large number of minor burns and scalds. In recent years, the company has gradually purchased some welder-specific protective clothing and shoes, reducing such accidents. 2.2 Manganese Poisoning Accident From April to July 1996, the boiler maintenance division was manufacturing impellers for a pulverizer. Two welders were assigned to be responsible for all welding work, using ordinary J422 and J507 welding rods. During the welding process, due to long continuous working hours and the welders' lack of attention to personal safety protection, such as failing to wear masks or work intermittently, after several months of welding work, a subsequent medical examination revealed that both welders had manganese poisoning, and they were subsequently hospitalized for treatment. 2.3 Smoke and Dust Damage Accidents In May 1995, during a minor overhaul of the unit, a welder entered the flue to perform welding repairs. Due to the extremely poor welding environment and dense smoke and dust, and the welder's lack of sufficient attention to safety precautions, he suffocated and fainted a few minutes after welding began. He was rescued from the scene by the supervisor and survived. Later, the company developed detailed preventive measures for this incident and provided gas masks, ensuring that similar accidents did not occur again. [b]3 Types of Welding Accidents in Thermal Power Plants and Preventive Measures[/b] 3.1 Fires The main sources of fire hazards include: gas welding flames, electric arcs, molten slag, molten iron splashes, and spontaneous combustion of gases. Fires occur when these hazards come into contact with flammable or combustible materials. Therefore, the main fire prevention measures include: Welding work areas must not contain wood (shavings), grease, or other flammable or combustible materials; these items should generally be at least 10 meters away from the work site; outdoor welding and cutting operations must be protected against wind to prevent sparks from flying; welding and cutting operations should not be carried out when the wind force exceeds level 5; regardless of whether working on flat ground or at height, measures must be taken to prevent the splashing and falling of molten metal slag; before leaving the site, a check must be conducted to confirm that no embers remain; the use and maintenance of gas cylinders and pressure regulators during gas welding must be carried out in accordance with relevant regulations and procedures, and they must not be exposed to heat, impact, or contaminated with grease; when welding near potential fire hazards, necessary fire-fighting equipment must be readily available. 3.2 Explosion The main hazardous factors for explosions include: improper use of gas cylinders and pressure regulators, improper operation of gas welding and cutting, improper welding and cutting of fuel containers and pipelines, and improper welding and cutting of pressurized containers and pipelines. Explosions mainly occur due to violations of relevant safety management regulations, procedures, or safe operating procedures during work. Therefore, the main preventative measures against explosions include: oxygen cylinders and acetylene cylinders should be inspected regularly as required; cylinders that have reached their expiration date or failed inspection should not be used; oxygen cylinders should not be transported in the same vehicle as acetylene cylinders or other flammable cylinders or materials; during transportation, storage, and use, avoid violent vibrations and collisions to prevent brittle fracture and explosion; cylinders should have caps and shock-absorbing rings; cylinders should be protected from direct heat or sunlight exposure; during operation, oxygen cylinders should be kept at least 5 meters away from acetylene cylinders, open flames, or heat sources; during transportation, storage, and use, avoid contaminating oxygen cylinders and pressure regulators with grease; gas welding and cutting operations are prohibited when explosive dust or other hazardous factors are present at the work site; flammable and explosive materials should be kept at least 10 meters away from the work area. Outside of a certain distance (m), metal materials must not be cut directly on cement surfaces. In the event of backfire during gas welding or cutting, appropriate measures must be taken immediately to shut off the oxygen and acetylene regulating valves. If an oxygen or acetylene hose or pressure regulator burns or explodes, the main valve of the gas cylinder must be immediately shut off. Welding and cutting of fuel containers and pipelines, as well as pressurized containers and pipelines, must be carried out only with strict and feasible accident prevention measures; otherwise, it is prohibited. 3.3 Electric Shock The main hazards of electric shock include: easily conductive welding work environments (such as dampness, metal containers, etc.), and leaky welding equipment and tools. Electric shock mainly occurs due to violations of relevant safety management procedures and regulations during operation, resulting in contact between the human body and a conductive body. Therefore, the main preventive measures against electric shock include: When welding inside metal containers or on other metal structures, or welding in humid environments, it is crucial to strengthen personal protection. Insulated shoes, leather gloves, and rubber mats or other insulating pads must be worn, and a supervisor must be present. In case of danger, the power supply should be immediately cut off. During operation, it is strictly forbidden to touch conductive materials indiscriminately, especially when the body is sweaty or clothing is damp. Develop a good habit of conducting safety checks before work, first checking whether the grounding and neutral connections are intact and reliable, and then checking whether the insulation protection is in place and whether the contact points are reliably insulated. When changing welding machine joints, reconnecting secondary circuits, moving the welding machine, replacing fuses, or repairing the welding machine, the power supply should be cut off before proceeding with other work. 3.4 Burns and Scalds The main risk factors for burns and scalds include: gas welding flames, electric arcs, molten slag, molten iron splashes, and spontaneous combustion of gases. These risk factors are not only the source of fires but also the source of burns and scalds. Burns and scalds occur when these hazards come into contact with the human body. Therefore, in addition to the same preventive measures as for fire, precautions for burns and scalds should also include: taking necessary protective measures before work, such as wearing protective clothing and shoes; paying attention to standing position at the work site, especially avoiding standing directly below welding or cutting points; ensuring the welding nozzle is not pointed at people when igniting gas welding; and avoiding welding or cutting operations directly on concrete surfaces to prevent sparks from flying. 3.5 Arc Radiation The main hazard of arc radiation is the arc light itself, which can cause glare, photokeratitis (commonly known as "spotting"), dermatitis, etc. The arc radiation intensity of argon arc welding is greater than that of shielded metal arc welding, and strong ultraviolet radiation can cause serious skin diseases such as erythema and blisters. Therefore, preventive measures against arc radiation mainly include: strengthening personal protective measures, such as wearing work clothes and goggles; setting up protective screens at the work site to block arc light; and using non-reflective materials that absorb light for interior wall finishes when working indoors. 3.6 High-Frequency Electromagnetic Radiation The main hazard of high-frequency electromagnetic radiation is the high-frequency electromagnetic field generated during the arc ignition of argon arc welding. The main harms of high-frequency electromagnetic radiation to the human body are neurasthenia and autonomic nervous system dysfunction, and in severe cases, abnormal blood pressure. Although the duration of each high-frequency oscillator activation during argon arc welding is only 2-3 seconds, and its impact on the human body is relatively small, protective measures are still necessary. Protective measures against high-frequency electromagnetic radiation mainly include: reducing the duration of high-frequency electrical contact; if the oscillator is used for arc ignition, the oscillator circuit should be immediately disconnected after arc ignition; ensuring proper grounding of the workpiece can greatly reduce high-frequency current; the closer the grounding point is to the workpiece, the better the situation; reducing the oscillator frequency without affecting usage; and shielding the welding cable and flexible wire. 3.7 Poisoning and Fume Damage The hazards of poisoning and fume damage are the fumes and toxic gases generated during the welding process. The main hazards of welding fumes include welder's pneumoconiosis, manganese poisoning, and metal fume fever. Toxic gases can damage the respiratory system and even the entire body. Protective measures against poisoning and dust damage mainly include: ensuring proper ventilation and dust removal during welding, especially when welders enter confined spaces; using welding rods or wires with low dust generation, provided the welding materials can guarantee their process and mechanical properties; and ensuring welders take personal protective measures, especially wearing protective masks. 3.8 Radiation Damage The main hazard of radiation damage is the thorium-tungsten electrode used in argon arc welding. Thorium is a naturally occurring radioactive substance that emits alpha, beta, and gamma rays, which can cause chronic radiation damage and various diseases in the human body. Although the radioactivity concentration is relatively low at the welding site, it is significantly higher at locations where thorium-tungsten electrodes are sharpened, repaired, and especially stored. Therefore, protective measures are also necessary. Protective measures against radiation damage mainly include: washing hands with running water and soap after handling thorium-tungsten rods, and frequently washing work clothes and gloves; using dedicated grinding wheels to sharpen thorium-tungsten rods, and the grinding machine should be equipped with dust removal equipment; storing thorium-tungsten rods in sealed lead boxes with ventilation devices installed in the storage location; and selecting appropriate process specifications to avoid excessive burning of thorium-tungsten rods. 3.9 Noise Damage Noise sources are mainly naturally generated at the welding site or during the welding process. The main hazards of noise are its impact on the nervous system and damage to hearing. Protective measures against noise mainly include: welders wearing soundproof covers or earplugs; using sound-absorbing or sound-insulating materials at the work site and on welding equipment. 3.10 Equipment Damage Equipment damage is mainly caused by violations of relevant safety regulations or prolonged overload use during welding production, resulting in damage to the equipment being welded, welding machines used in welding and cutting processes, and electrical equipment used in processing. [b]4 Conclusion[/b] To ensure safe welding production, a multi-pronged approach is necessary. In addition to the specific accident prevention measures analyzed above, emphasis should be placed on management, particularly on safety education and training for employees, especially temporary workers and migrant workers, to ensure they consciously comply with all safety regulations and operating procedures. If the importance of welding safety is recognized in people's minds, welding accidents can certainly be avoided.